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1

Voyager 1 Has Entered Interstellar Space  

NASA Astrophysics Data System (ADS)

"We made it," Voyager project scientist Ed Stone announced at a 12 September briefing at NASA headquarters in Washington, D. C. NASA's Voyager 1 spacecraft, the most distant human-made object, is now the first such object to enter interstellar space, the space between the stars. "The 36-year-old probe is now sailing the uncharted waters of a new cosmic sea, and it has brought us along for the journey," Stone said.

Showstack, Randy

2013-09-01

2

The Voyager Journey to Interstellar Space  

NASA Astrophysics Data System (ADS)

Launched in 1977 to explore Jupiter, Saturn, Uranus, and Neptune, the two Voyager spacecraft continued their journeys beyond the planets as they searched for the heliopause, the boundary between the solar wind and the local interstellar medium. After traveling more than 23 billion kilometers, Voyager 1 left the heliosphere on August 25, 2012, and began returning the first in-situ observations of local interstellar space. Voyager 1 found a wall of interstellar plasma beyond the heliopause with a density forty times greater than inside and an interstellar magnetic field that is compressed and wrapped around the outside. Voyager 1 also observed the energy spectrum of low energy galactic cosmic ray protons that are excluded from the heliosphere by solar modulation, finding a peak intensity at ˜30 MeV. that is ten times the maximum intensity at 1 AU that occurs at ˜300 MeV. An overview of the journey and the new aspects of the interaction of the sun and the nearby region of the Milky Way will be discussed.

Stone, E. C.

3

Voyager mission support  

NASA Technical Reports Server (NTRS)

Mission support provided by Deep Space Network for Project Voyager is discussed. Mission operations covered include for Voyager 1 the far encounter 2, Saturn near encounter, and the post encounter phase, and for Voyager 2 the Jupiter Saturn cruise phase.

Fanelli, N.; Nance, H. E.

1981-01-01

4

Interstellar Probe: Impact of the Voyager and IBEX results on science and strategy  

NASA Astrophysics Data System (ADS)

The ongoing Voyager Interstellar Mission (VIM) and recent observations from the Interstellar Boundary Explorer (IBEX) and Cassini missions are providing significant new information about the interaction of the heliosphere with the very local interstellar medium (VLISM). With new observations have come significant new puzzles for describing the interaction physics. Direct measurements of the shocked, solar-wind flow speed are now possible (from Voyager 2) and show the flow remains supersonic. This is one more piece of evidence supporting the idea that the bulk of the energy density in the plasma resides in a non-thermal component that extends to very high energies. There are both quantitative and qualitative implications for the overall heliospheric structure. Observations of energetic neutral atoms (ENAs) by IBEX (in Earth orbit) from the interaction region(s) of the solar wind and the VLISM show unexpected structure on a variety of scales. In addition to the general “glow” of the sky in ENAs, IBEX data show a relatively narrow “ribbon” of atomic hydrogen emission from ˜200 to ˜6 keV, roughly circular, but asymmetric in intensity, and centered on an ecliptic longitude ˜221 degrees and ecliptic latitude of 39 degrees. The ribbon may be ordered by the interstellar magnetic field. It passes through, rather than being centered on, the “nose” from which the local, neutral interstellar wind enters the Heliosphere, indicating that the flow is not the primary driver of the system as had been thought previously. The neutrals from both the glow and ribbon are also characterized by non-thermal distribution functions. ENAs are observed at higher energies as well by the Ion and Neutral Camera (INCA) on Cassini (in orbit about Saturn). A “belt” of emission, broader than the ribbon but similar to it, is seen up to ˜50 keV. These observations emphasize the need for in situ measurements to understand the global nature of our local galactic environment, which is much more complex than previously thought. Only an interstellar probe with modern instruments and measurement requirements better defined by these recent observations can provide the new information required. Even more importantly, the broader scale of the interaction as revealed in these measurements suggests much greater flexibility in scientifically allowable, asymptotic trajectories from the heliosphere for the probe. This is a significant relaxation in the trajectory requirements that open up the trade space for Jupiter gravity assists to increase the flyout speeds.

McNutt, Ralph L.; Gruntman, Mike; Krimigis, Stamatios M.; Roelof, Edmond C.; Wimmer-Schweingruber, Robert F.

2011-11-01

5

Einstein's Symphony: A Gravitational Wave Voyage Through Space and Time  

NASA Astrophysics Data System (ADS)

Einstein's Symphony: A Gravitational Wave Voyage Through Space and Time is a gravitational wave astronomy planetarium show in production by a collaboration of scientists, filmmakers, and artisits from the Center for Gravitational Wave Astonomy (CGWA) at the University of Texas at Brownsville (UTB) and Montana State University (MSU). The project builds on the success of the interdisciplinary Celebrating Einstein collaboration. The artists and scientists who created the A Shout Across Time original film and the Black (W)hole immersive art installation for Celebrating Einstein are teaming with the Museum of the Rockies Taylor Planetarium staff and students to create a new full dome Digistar planetarium show that will be freely and widely distributed to planetaria in the US and abroad. The show uses images and animations filmed and collected for A Shout Across Time and for Black (W)hole as well as new images and animations and a new soundtrack composed and produced by the MSU School of Music to use the full capability of planetarium sound systems. The planetarium show will be narrated with ideas drawn from the Celebrating Einstein danced lecture on gravitational waves that the collaboration produced. The combination of products, resources, and team members assembled for this project allows us to create an original planetarium show for a fraction of the cost of a typical show. In addition, STEM education materials for G6-12 students and teachers will be provided to complement and support the show. This project is supported by the Texas Space Grant Consortium (TSGC), Montana Space Grant Consortium (MSGC), and the American Physical Society (APS).

Shapiro Key, Joey; Yunes, Nico; Grimberg, Irene

2015-01-01

6

Space Probe Launch  

NASA Technical Reports Server (NTRS)

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.

1970-01-01

7

Simplistic propulsion analysis of a breakthrough space drive for Voyager  

Microsoft Academic Search

When considering exploration beyond our solar system, speed is a critical factor. With the speeds achievable with current propulsion technology, interstellar distances cannot be traversed within a human life span. For example, the Voyager spacecraft would take approximately 80,000 years to traverse 4.3 light-years - the distance to our nearest neighboring star. In 1996 NASA established the Breakthrough Propulsion Physics

Malcolm D. K. Boston

2000-01-01

8

Exploring the Planets: Voyager  

NSDL National Science Digital Library

This site describes the Voyager exhibit at the National Air and Space Museum and gives additional information about the Voyagers that were launched into space and the one remaining in the museum. The Voyager spacecraft displayed in the Exploring the Planets gallery is similar to the two Voyagers sent to explore Jupiter, Saturn, Uranus, and Neptune. This portion of the exhibit details the Voyager missions, the spacecraft, and its instruments. Sixteen of the Voyager components and instrumentation are discussed in detail along with its unique power supply. The Museum's spacecraft is a full-scale replica of Voyager, parts of which were used for pre-launch engineering tests. Voyager is suspended above the Outer Planets display, which highlights some of the discoveries made through data and imagery returned by Voyagers 1 and 2.

9

Future studies of planetary rings by space probes  

NASA Technical Reports Server (NTRS)

Recent space probe observations of the rings of Jupiter and Saturn have furnished a substantial enhancement of the current understanding of the outer planets' rings. Voyager 2 offers further opportunities for the study of the Neptune and Uranus ring systems. The Galileo mission to Jupiter furnishes the first opportunity for long term space probe studies of a planetary ring system. It is suggested that an appropriately instrumented Saturn orbiter would not only provide a similar opportunity for the study of the Saturn rings, but may also be the only means by which to adequately address the nature of the diverse phenomena displayed by this prototypical planetary ring system.

Stone, E. C.

1984-01-01

10

The Challenge of Space Futures: Starcomber's Galactic Voyage to Xeranthemom.  

ERIC Educational Resources Information Center

Describes a curriculum enrichment activity for gifted middle school students. Students design a long-range space travel vehicle and plan for colonizing a discovered planet. Students contact people in science and industry and produce a handbook for space travel and colonization. (DB)

Shimonauff, Jacqueline

1998-01-01

11

Nick Sagan Reflects on Voyager 1 and the Golden Record  

NASA Astrophysics Data System (ADS)

When scientists confirmed on 12 September that NASA's Voyager 1 spacecraft had entered interstellar space (Eos, 94(39), 339, doi:10.1002/2013EO390003), the probe was acknowledged as the first human-made object to travel into that realm. The probe and its twin, Voyager 2, each carry a 12-inch gold-plated copper disk, known as the Golden Record.

Showstack, Randy

2013-10-01

12

The navigation of space probes  

NASA Technical Reports Server (NTRS)

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.

Fliegel, H. F.; Ohandley, D. A.; Zielenbach, J. W.

1974-01-01

13

Interstellar Probe: Impact of the Voyager and IBEX results on science and strategy  

Microsoft Academic Search

The ongoing Voyager Interstellar Mission (VIM) and recent observations from the Interstellar Boundary Explorer (IBEX) and Cassini missions are providing significant new information about the interaction of the heliosphere with the very local interstellar medium (VLISM). With new observations have come significant new puzzles for describing the interaction physics. Direct measurements of the shocked, solar-wind flow speed are now possible

Ralph L. McNutt; Mike Gruntman; Stamatios M. Krimigis; Edmond C. Roelof; Robert F. Wimmer-Schweingruber

2011-01-01

14

PROBING THE NATURE OF THE HELIOSHEATH WITH THE NEUTRAL ATOM SPECTRA MEASURED BY IBEX IN THE VOYAGER 1 DIRECTION  

SciTech Connect

We are able to show by comparing modeled energetic neutral atoms (ENAs) spectra to those measured by Interstellar Boundary Explorer (IBEX) that the models along the Voyager 1 (V1) trajectory that best agree with the low energy IBEX data include extra heating due to ram and magnetic energy in the quasi-stagnation region or a kappa ion distribution (with ? = 2.0) in the outer heliosheath. The model explored is the multi-ion, multi-fluid (MI-MF) which treats the pick-up ions and the thermal ion fluids with separate Maxwellian distributions. These effects are included ad hoc in the modeled ENA since they are not present in the model. These results indicate that the low energy spectra of ENAs as measured by IBEX is sensitive to the physical nature of the heliosheath and to effects not traditionally present in current global models. Therefore, by comparing the low energy ENA spectra to models, we can potentially probe the heliosheath in locations beyond those probed by V1 and Voyager 2 (V2)

Opher, M.; Prested, C. [Astronomy Department, Boston University, 725 Commonwealth Avenue, Boston, MA (United States)] [Astronomy Department, Boston University, 725 Commonwealth Avenue, Boston, MA (United States); McComas, D. J. [Southwest Research Institute, San Antonio, TX 78238 (United States)] [Southwest Research Institute, San Antonio, TX 78238 (United States); Schwadron, N. A. [Department of Physics and Space Science Center, University of New Hampshire, Durham, NH 03824 (United States)] [Department of Physics and Space Science Center, University of New Hampshire, Durham, NH 03824 (United States); Drake, J. F., E-mail: mopher@bu.edu [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742 (United States)

2013-10-20

15

Voyager mission support  

NASA Technical Reports Server (NTRS)

The Deep Space Network Report on Tracking and Data Acquisition for Project Voyager is presented. Long time base observation and system scans are described. Results of adaptive tracking techniques on Voyager 2 are reported. The reporting period is December 1980 through March 1981.

Fanelli, N.; Nance, H. E.

1981-01-01

16

Galileo Space Probe News Conference  

NASA Astrophysics Data System (ADS)

This NASA Kennedy Space Center (KSC) video release presents Part 3 of a press conference from Ames Research Center (ARC) regarding the successful entry of the Galileo Space Probe into Jupiter's atmosphere. The press conference panel is comprised of twelve principal investigators and project scientists that oversee the Galileo mission. The press conference question and answer period is continued from Part 2. Atmospheric thermal structure, water abundances, wind profiles, radiation, cloud structure, chemical composition, and electricity are among the topics discussed. The question and answer period is followed by a presentation in which all of the visuals that are shown during the press conference are reviewed. The video ends with several animations depicting the entry of the probe, descent, and the first measurements of the Jovian atmosphere, historical footage of the building of the probe, and a short interview with Dr. Richard Young (Galileo Probe Scientist, ARC). Parts 1 and 2 of the press conference can be found in document numbers NONP-NASA-VT-2000001073, and NONP-NASA-VT-2000001074.

1996-01-01

17

Voyager observations of ion phase space densities in the Jovian magnetosphere  

NASA Astrophysics Data System (ADS)

Data from the Voyager low-energy charged particle experiment (LECP) were used to calculate ion phase space densities in Jupiter's magnetosphere. The calculation of F at constant mu and J(2) requires the determination of particle fluxes at specific pitch angles and energies. It is shown that the greatest uncertainties in the determination of F from LECP data arise from the fits to the measured pitch angle distributions and differential energy spectra. An estimate is provided of this uncertainty and of others arising from model radial diffusion coefficients and magnetic fields. The general nature of the curves is consistent with inward diffusion of these energetic ions from the outer magnetosphere combined with losses near but starting beyond the orbit of Io. These losses are not consistent with simple satellite sweeping by Io alone and are probably due to an Io-torus wave-particle interaction. The lifetime against loss deduced from the data is approximately 20,000 s near Io and is a value consistent with strong diffusion losses. The measured ion loss rate declines much more rapidly than the strong diffusion loss rate as L increases from 7 to 9, suggesting that the loss rate is well below the strong-diffusion rate beyond 7 Jupiter radii for ions observed by the LECP.

Paonessa, M.

1985-01-01

18

Voyager at Saturn  

NASA Technical Reports Server (NTRS)

The spacecraft design and operations and mission results of the Voyager Project are reviewed with particular emphasis on the results of the Saturn encounters. The mission was undertaken by two spacecraft: Voyager 2, launched first on August 20, 1977 on a lower energy trajectory to Jupiter, Saturn, Uranus and Neptune; and Voyager 1, launched on September 5, 1977 on a higher energy trajectory to closer flybys of Jupiter and Saturn. The Voyager spacecraft make use of earlier Mariner and Viking Orbiter design concepts, with additional capabilities for solar independent power, long-range communications and autonomy as well as equipment for the 11 science investigations. The Voyager operations system consists of a ground data system, missions operations system, and support by the Mission Control and Computer Center and Deep Space Network. Among the results of the Jupiter encounter are data concerning the magnetospheric structure and atmospheric dynamics of the planet and the surface features of the Galilean satellites. The encounters with Saturn produced scientific data concerning wind speeds, auroral emissions, and radio emissions from the planet, the fine structure of the previously known and newly discovered rings, the surface features of the satellites and the atmospheric composition and conditions of Titan. Voyager 1 is presently making field and particle measurements on its flight into interstellar space, while Voyager 2 is headed for an encounter with Uranus in January 1986 and Neptune in August 1989.

Heacock, R. L.

1981-01-01

19

Galileo Space Probe News Conference  

NASA Astrophysics Data System (ADS)

This NASA Kennedy Space Center (KSC) video release presents Part 1 of a press conference regarding the successful entry of the Galileo Space Probe into Jupiter's atmosphere. The press conference panel is comprised of twelve principal investigators and project scientists that oversee the Galileo mission. Among these panelists, William J. O'Neil (Jet Propulsion Lab.) begins the video praising all of the scientists that worked on the orbiter mission. He then presents a visual overview of Galileo's overall mission trajectory and schedule. Marcie Smith (NASA Ames Research Center) then describes the Galileo Probe mission and the overall engineering and data acquisition aspects of the Probe's Jupiter atmospheric entry. Dr. Richard Young (NASA Ames Research Center) follows with a brief scientific overview, describing the measurements of the atmospheric composition as well as the instruments that were used to gather the data. Atmospheric pressure, temperature, density, and radiation levels of Jupiter were among the most important parameters measured. It is explained that these measurements would be helpful in determining among other things, the overall dynamic meteorology of Jupiter. A question and answer period follows the individual presentations. Atmospheric thermal structure, water abundances, wind profiles, radiation, cloud structure, chemical composition, and electricity are among the topics discussed. Parts 2 and 3 of the press conference can be found in document numbers NONP-NASA-VT-2000001074, and NONP-NASA-VT-2000001075.

1996-01-01

20

Gravity Probe B Space Vehicle  

NASA Technical Reports Server (NTRS)

The space vehicle for Gravity Probe B (GP-B) arrives at the launch site at Vandenburg Air Force Base. GP-B is the relativity experiment being developed at Stanford University to test two extraordinary predictions of Albert Einstein's general theory of relativity. The experiment will measure, very precisely, the expected tiny changes in the direction of the spin axes of four gyroscopes contained in an Earth-orbiting satellite at a 400-mile altitude. So free are the gyroscopes from disturbance that they will provide an almost perfect space-time reference system. They will measure how space and time are very slightly warped by the presence of the Earth, and, more profoundly, how the Earth's rotation very slightly drags space-time around with it. These effects, though small for the Earth, have far-reaching implications for the nature of matter and the structure of the Universe. GP-B is among the most thoroughly researched programs ever undertaken by NASA. This is the story of a scientific quest in which physicists and engineers have collaborated closely over many years. Inspired by their quest, they have invented a whole range of technologies that are already enlivening other branches of science and engineering. Scheduled for launch in 2003 and managed for NASA by the Marshall Space Flight Center, development of the GP-B is the responsibility of Stanford University, with major subcontractor Lockheed Martin Corporation.

2003-01-01

21

Titan: Evidence for seasonal change - A comparison of Hubble Space Telescope and Voyager images  

Microsoft Academic Search

A comparison of images of Titan obtained by the HST in August, 1990 with Voyager 1 and 2 images respectively obtained 10 and 9 years earlier has indicated a reversal of the seasonal hemispheric brightness asymmetry near 440 and 550 nm wavelengths; the northern hemisphere is in the more recent observations the brighter of the two, by about 10 percent.

John Caldwell; Cindy C. Cunningham; David Anthony; H. P. White; E. J. Groth; H. Hasan; K. Noll; P. H. Smith; M. G. Tomasko; H. A. Weaver

1992-01-01

22

Space Systems Failures: Disasters and Rescues of Satellites, Rocket and Space Probes  

NASA Astrophysics Data System (ADS)

In the 1960s and 1970s deep space missions were dispatched in pairs in case one was lost in launch or failed during its journey. Following the triumphs of the Viking landings on Mars in 1976 and both Voyagers spacecraft successfully surveying the outer giant planets of the Solar System, it was decided by NASA to cut costs and send out just a single probe. Although Magellan successfully mapped Venus by radar, it suffered from problems during the flight. Then came the loss of Mars Observer, whose engine exploded as it was preparing to enter Mars' orbit because it was using technology designed for Earth's satellites and the engine was not suited to spending several months in space.

Harland, David M.; Lorenz, Ralph

23

Exploring the Galaxy using space probes  

Microsoft Academic Search

This paper investigates the possible use of space probes to explore the Milky Way, as a means both of finding life elsewhere in the Galaxy and as finding an answer to the Fermi paradox. I simulate exploration of the Galaxy by first examining how long time it takes a given number of space probes to explore 40,000 stars in a

R. Bjørk

24

Exploring the Galaxy using space probes  

Microsoft Academic Search

This paper investigates the possible use of space probes to explore the Milky Way, as a means both of finding life elsewhere in the Galaxy and as finding an answer to the Fermi paradox. Exploration of the Galaxy is simulated by first examining how long time it takes a given number of space probes to explore 40000 stars in a

R. Bjørk

2007-01-01

25

Megabit memory for Helios space probe  

Microsoft Academic Search

A new 0.5 Mbit random access ferrite core memory has been developed that overcomes the disadvantages of conventional magnetic tape memories when used in deep space probes. It will be used in the Helios space probe to be launched at the end of 1974.

M. Florjancic; H. Reiner

1974-01-01

26

NASA Facts, Voyager.  

ERIC Educational Resources Information Center

This document is one of a series of publications of the National Aeronautics and Space Administration (NASA) on facts about the exploration of Jupiter and Saturn. This NASA mission consists of two unmanned Voyager spacecrafts launched in August and September of 1977, and due to arrive at Jupiter in 1979. An account of the scientific equipment…

National Aeronautics and Space Administration, Washington, DC. Educational Programs Div.

27

Voyager 2 Jupiter encounter  

NASA Technical Reports Server (NTRS)

A NASA News Release is presented which contains the following: (1) general release; (2) two views of Voyager 2 flight past Jupiter; (3) Voyager mission summary; (4) Voyager 1 science results; (5) Jupiter science objectives; (6) Jupiter the planet and its satellites; (7) Voyager experiments; (8) planet comparison; (9) a list of Voyager science investigators and (10) the Voyager team.

1979-01-01

28

Gigapan Voyage for Robotic Recon  

NASA Technical Reports Server (NTRS)

Gigapan Voyage (GV) is a self-contained remotely-operable Gigapan capturing system that is currently being developed by the Intelligent Robotics Group (IRG) at NASA Ames Research Center. Gigapan Voyage was primarily designed to be integrated onto Johnson Space Center s Lunar Electric Rovers (LER). While on LER, Gigapan Voyage was used by scientists and astronauts during the 2009 and 2010 Desert RATS field tests. The concept behind Gigapan Voyage is to merge all the sub-components of the commercial GigaPan system into an all-in-one system that can capture, stitch, and display Gigapans in an automated way via a simple web interface. The GV system enables NASA to quickly and easily add remote-controlled Gigapan capturing capability onto rovers with minimal integration effort. Key Words: Geology, NASA, Black Point Lava Flow, Robot, K10, LER, Gigapan Voyage, Desert RATS, Intelligent Robotics Group

Lee, Susan Y.; Moorse, Theodore Fitzgerald; Park, Eric J.

2010-01-01

29

Exploring the Galaxy using space probes  

Microsoft Academic Search

This paper investigates the possible use of space probes to explore the Milky\\u000aWay, as a means both of finding life elsewhere in the Galaxy and as finding an\\u000aanswer to the Fermi paradox. I simulate exploration of the Galaxy by first\\u000aexamining how long time it takes a given number of space probes to explore\\u000a40,000 stars in a

Rasmus Bjoerk

2007-01-01

30

Voyager design and flight loads comparison  

NASA Technical Reports Server (NTRS)

Estimates of flight loads for Voyager 1 and Voyager 2 are summarized. These member loads are obtained by using the measured flight accelerations at the launch vehicle/spacecraft interface as forcing functions for the Voyager mathematical model. The flight loads are compared to the Voyager design loads obtained from the shock spectra/impedance method and to the loads obtained using space vehicle transient loads analysis. Finally, based on these data, an assessment of the shock spectra/impedance loads method used for Voyager is presented.

Chen, J. C.; Garba, J. A.; Day, F. D., III

1979-01-01

31

Voyager Cartography  

NASA Technical Reports Server (NTRS)

The Jovian and Saturnian satellites are being mapped at several scales from Voyager 1 and 2 data. The maps include specially formatted color mosaics, controlled photomosaics, and airbrush maps. More than 500 Voyager images of the Jovian and Saturnian satellites were radiometrically processed in preparation for cartographic processing. Of these images, 235 were geometrically transformed to map projections for base mosaic compilations. Special techniques for producing hybrid photomosaic/airbrush maps of Callisto are under investigation. The techniques involve making controlled computer mosaics of all available images with highest resolution images superimposed on lowest resolution images. The mosaics are then improved by airbrushing: seams and artifacts are removed, and image details enhanced that had been lost by saturation in some images. A controlled mosaic of the northern hemisphere of Rhea is complete, as is all processing for a similar mosaic of the equatorial region. Current plans and status of the various series are shown in a table.

Batson, R. M.; Bridges, P. M.; Mullins, K. F.

1985-01-01

32

Ocean Voyagers  

NSDL National Science Digital Library

Ocean Voyagers is an educational outreach initiative consisting of an interdisciplinary curriculum program. It is designed to allow middle school teachers and students to gain real-world knowledge about oceanographic science, social science, maritime cultures, communication, literature, and the language arts. This site includes: integrated lesson plans on oceanographic science, maritime life and lore, technology and communications, and profiles of the Navy oceanographic survey fleet.

33

Space Place: What is the Secret Code Used by the Voyager Spacecraft?  

NSDL National Science Digital Library

This module from the Space Place Web site allows students to learn the secret code spacecraft use to send images back from space. It introduces the language of computers and spacecraft. Binary and hexadecimal notations are explained. The Space Place is an educational NASA site for children and adults with activities and facts related to the exploration of space â past, current and future. Some activities are computer-interactive and many are real-world-interactive.

2011-01-01

34

Encounter with Jupiter. [Pioneer 10 space probe  

NASA Technical Reports Server (NTRS)

Pioneer 10 space probe's encounter with the Jupiter is discussed in detail. Tables are presented which include data on the distances during the encounter, times of crossing satellite orbits, important events in the flight near Jupiter, and time of experiments. Educational study projects are also included.

1975-01-01

35

Ka band TWTA for space probes  

Microsoft Academic Search

Thales electron devices has many years of experience in the manufacture of traveling wave tube amplifiers (TWTA) for space probes, which must send large quantities of data back to Earth. The application of TWTA have traditionally used the X band, around 8 GHz, with RF power ranging from 20 to 40 watts. However, the upcoming generation of spacecraft will also

F. Andre; A. Gallien; P. Boone

2003-01-01

36

Voyager's decade of wonder  

SciTech Connect

The development and implementation of the Voyager missions are reviewed. The interplanetary missions preceding Voyager are discussed, focusing on the technological development leading up to the Voyager spacecraft. The main results from Voyager observations of Jupiter, Saturn, and Uranus are outlined. Also, consideration is given to the prospects for observations of Neptune.

Mclaughlin, W.I. (California Institute of Technology, Pasadena (USA))

1989-07-01

37

NASA Facts: Voyager  

NASA Technical Reports Server (NTRS)

A news release on NASA's Voyager project is presented. The spacecraft, science instrumentation, experiments and a mission profile are described. A drawing identifying Voyager's major components and instrumentation was included along with diagrams showing the path of Voyager 1 (JST trajectory) past Jupiter, and the path of Voyager 2 (JXT trajectory) during its encounter with Jupiter. An exercise for student involvement was also provided.

1977-01-01

38

Summary of Voyager Design and Flight Loads  

NASA Technical Reports Server (NTRS)

Estimates of flight loads for Voyager 1 and Voyager 2 are summarized and compared to the Voyager design loads obtained from the shock spectra/impedance method and to the loads obtained using space vehicle transient loads analysis. These estimates were obtained by using the measured flight accelerations at the launch vehicle/spacecraft interface as forcing functions for the Voyager mathematical model. Based on these data, an assessment of the shock spectra/impedance loads method used for Voyager is presented. The following conclusions were reached: (1) the shock spectra approach provided reasonable conservative design loads for Voyager, (2) care has to be executed to insure that all critical events are accounted for in constructing shock spectra envelopes, (3) the selection of critical events is not always obvious, especially for those flight events wherein the spacecraft dynamic characteristics are important, and (4) the success of the method is strongly dependent on the analysts' experience and judgement.

Chen, J. C.; Garba, J. A.; Day, F. D., III

1978-01-01

39

What do space voyagers value? a thematic analysis of the narratives of spaceflight veterans  

NASA Astrophysics Data System (ADS)

Values are desired outcomes, differing in importance, that guide people's lives. Considerable anecdotal evidence suggests that astronauts and cosmonauts experience changes in values as a consequence of their experiences in space. Among the most frequently mentioned changes are a greater appreciation of the unity of Earth and humanity, and an increase in self-confidence. Two preliminary studies by the author have confirmed significant changes in values among (a) four Apollo-era American astronauts and (b) ten male astronauts from the Apollo, Mercury, and Gemini programs, three female veterans of the Shuttle-Mir, and two male high-ranking NASA administrators. The current study expanded the database to 104 space veterans from the US, Russia, and other nations, whose narratives (memoirs, media interviews, and oral histories) were subjected to thematic content analysis for references to Schwartz's well-established value categories. Significant pre-flight differences were found related to nationality, space age era (through vs. later than 1975), and longest flight duration. Comparing references from the pre-flight period with those to the time of the mission and then to post-return from space, we found a U-shaped curve for the values of Achievement, Power, and Self-Direction, and steady increases across periods for Enjoyment and Universalism. Compared to multicultural norms, astronauts showed higher values placed on Achievement, Enjoyment (their two primary values), and Power (after the mission only), and lower values on Security, Self-Direction (after the mission), Universalism, and Tradition.

Suedfeld, Peter

40

Thermodynamic considerations in the support of life for long space voyages  

NASA Technical Reports Server (NTRS)

The essential requirements for the maintenance of life, particularly human life, on isolated space missions of long duration were investigated through the study of extended irreversible thermodynamics. The characterization of a four trophic level system was developed. Questions of stability are discussed.

Iberall, A. S.; Cardon, S. Z.

1979-01-01

41

What do space voyagers value? a thematic analysis of the narratives of spaceflight veterans  

Microsoft Academic Search

Values are desired outcomes, differing in importance, that guide people's lives. Considerable anecdotal evidence suggests that astronauts and cosmonauts experience changes in values as a consequence of their experiences in space. Among the most frequently mentioned changes are a greater appreciation of the unity of Earth and humanity, and an increase in self-confidence. Two preliminary studies by the author have

Peter Suedfeld

2008-01-01

42

The Voyager Neptune travel guide  

NASA Technical Reports Server (NTRS)

The Voyager mission to the giant outer planets of our solar system is described. Scientific highlights include interplanetary cruise, Jupiter, Saturn, Uranus, and their vast satellite and ring systems. Detailed plans are provided for the August 1989 Neptune encounter and subsequent interstellar journey to reach the heliopause. As background, the elements of an unmanned space mission are explained, with emphasis on the capabilities of the spacecraft and the scientific sensors. Other topics include the Voyager Grand Tour trajectory design, deep-space navigation, and gravity-assist concepts. The Neptune flyby is animated through the use of computer-generated, flip-page movie frames that appear in the corners of the publication. Useful historical information is also presented, including facts associated with the Voyager mission. Finally, short summaries are provided to describe the major objectives and schedules for several space missions planned for the remainder of the 20th century.

Kohlhase, Charles (editor)

1989-01-01

43

The Voyager Neptune travel guide.  

NASA Astrophysics Data System (ADS)

This publication describes, with numerous illustrations, the Voyager mission to explore the giant outer planets of our solar system. Scientific highlights include interplanetary cruise, Jupiter, Saturn, Uranus, and their vast satellite and ring systems. Detailed plans are provided for the August 1989 Neptune encounter and subsequent interstellar journey to reach the heliopause. As background, the elements of an unmanned space mission are explained, with emphasis on the capabilities of the spacecraft and the scientific sensors. Other topics include the Voyager Grand Tour trajectory design, deep-space navigation, and gravity-assist concepts. The Neptune flyby is animated through the use of computer-generated, flip-page movie frames. Useful historical information is also presented, including remarkable or gee-whiz facts associated with the Voyager mission. Finally, short summaries are provided to describe the major objectives and schedules for several exciting space missions planned for the remainder of the 20th century.

Kohlhase, C.

1989-06-01

44

Exploring the Galaxy using space probes  

E-print Network

This paper investigates the possible use of space probes to explore the Milky Way, as a means both of finding life elsewhere in the Galaxy and as finding an answer to the Fermi paradox. I simulate exploration of the Galaxy by first examining how long time it takes a given number of space probes to explore 40,000 stars in a box from -300 to 300 pc above the Galactic thin disk, as a function of Galactic radius. I then model the Galaxy to consist of $\\sim{}260,000$ of these 40,000 stellar systems all located in a defined Galactic Habitable Zone and show how long time it takes to explore this zone. The result is that with 8 probes, each with 8 subprobes $\\sim{}4%$ of the Galaxy can be explored in $2.92\\cdot{}10^{8}$ years. Increasing the number of probes to 200, still with 8 subprobes each, reduces the exploration time to $1.52\\cdot{}10^{7}$ years.

Rasmus Bjoerk

2007-04-23

45

The Voyager Interstellar Mission.  

PubMed

The Voyager Interstellar Mission began on January 1, 1990, with the primary objective being to characterize the interplanetary medium beyond Neptune and to search for the transition region between the interplanetary medium and the interstellar medium. At the start of this mission, the two Voyager spacecraft had already been in flight for over twelve years, having successfully returned a wealth of scientific information about the planetary systems of Jupiter, Saturn, Uranus, and Neptune, and the interplanetary medium between Earth and Neptune. The two spacecraft have the potential to continue returning science data until around the year 2020. With this extended operating lifetime, there is a high likelihood of one of the two spacecraft penetrating the termination shock and possibly the heliopause boundary, and entering interstellar space before that time. This paper describes the Voyager Interstellar Mission--the mission objectives, the spacecraft and science payload, the mission operations system used to support operations, and the mission operations strategy being used to maximize science data return even in the event of certain potential spacecraft subsystem failures. The implementation of automated analysis tools to offset and enable reduced flight team staffing levels is also discussed. PMID:11540770

Rudd, R P; Hall, J C; Spradlin, G L

1997-01-01

46

Galileo Space Probe News Conference. Part 1  

NASA Technical Reports Server (NTRS)

This NASA Kennedy Space Center (KSC) video release presents Part 1 of a press conference regarding the successful entry of the Galileo Space Probe into Jupiter's atmosphere. The press conference panel is comprised of twelve principal investigators and project scientists that oversee the Galileo mission. Among these panelists, William J. O'Neil (Jet Propulsion Lab.) begins the video praising all of the scientists that worked on the orbiter mission. He then presents a visual overview of Galileo's overall mission trajectory and schedule. Marcie Smith (NASA Ames Research Center) then describes the Galileo Probe mission and the overall engineering and data acquisition aspects of the Probe's Jupiter atmospheric entry. Dr. Richard Young (NASA Ames Research Center) follows with a brief scientific overview, describing the measurements of the atmospheric composition as well as the instruments that were used to gather the data. Atmospheric pressure, temperature, density, and radiation levels of Jupiter were among the most important parameters measured. It is explained that these measurements would be helpful in determining among other things, the overall dynamic meteorology of Jupiter. A question and answer period follows the individual presentations. Atmospheric thermal structure, water abundances, wind profiles, radiation, cloud structure, chemical composition, and electricity are among the topics discussed. Parts 2 and 3 of the press conference can be found in document numbers NONP-NASA-VT-2000001074, and NONP-NASA-VT-2000001075.

1996-01-01

47

Voyager cartography  

NASA Technical Reports Server (NTRS)

The Jovian and Saturnian satellites are being mapped at several scales from Voyager 1 and 2 data. The maps are especially formatted color mosaics, controlled photomosaics, and airbrush maps. At 1:5,000,000 scale, mapping of Io, Europa, and Ganymede is complete. At 1:15,000,000 scale, mapping of Io and Europa is complete, and mapping of Ganymede is approximately complete. A controlled mosaic of Rhea has been compiled as a Digital Image Model (DIM) in the same format as is being used for Mars. The mosaic is being formatted for publication as a two-sheet set (Lambert Azimuthal Equal Area, Mercator, and Polar Stereographic projections). Magnetic tape copies of the DIM have been distributed to regional Planetary Image Facilities and other interested users. The DIM has a scale of 1/16 degree/pixel, corresponding to approximately 833 m/pixel on Rhea. Details of the status of the various map series are reported quarterly to Planetary Geology Principal Investigators.

Batson, R. M.; Lee, E. M.; Mullins, K. F.

1987-01-01

48

Employment of Asteroids for Movement Space Ship and Probes  

NASA Technical Reports Server (NTRS)

At present, rockets are used to change the trajectory of space ships and probes. This method is very expensive and requires a lot of fuel, which limits the feasibility of space stations, interplanetary space ships, and probes. Sometimes space probes use the gravity field of a planet. However, there are only 9 planets in our solar system and they are separated by great distances. There are tens of millions of asteroids in outer space. The author offers a revolutionary method for changing the trajectory of space probes. This method uses the kinetic or rotary energy of asteroids, meteorites or other space bodies (small planets, natural planet satellites, etc.). to increase (to decrease) ship (probe) speed up to 1000 m/sec (or more) and to get any new direction in outer space. The flight possibilities of space ships and probes are increased by a factor of millions.

Bolonkin, Alexander

2002-01-01

49

"Voyager": An Educational Card Game  

ERIC Educational Resources Information Center

"Voyager" is an educational card game involving scientific satellites, developed for use in schools with children aged 9 to 13 years. The idea of the game is to improve pupils' knowledge about the large number of scientific satellites there are in space in a fun way, while also practising numeracy skills. Several copies of the game were produced…

Smith, David Ryan

2003-01-01

50

Voyager mission support  

NASA Technical Reports Server (NTRS)

Tracking and data acquisition for Project Voyager are discussed for the period of April through June 1981. Voyager 1 was in the extended mission phase of operations. Voyager 2 completed the cruise phase of its operations and on 5 June entered the observatory phase of the Saturn encounter operations.

Fanelli, N.; Nance, H. E.

1981-01-01

51

Voyager's Last Encounter  

NASA Technical Reports Server (NTRS)

This video describes Voyager 2's encounter with Neptune. Computer animation and actual data convey Voyager's discoveries such as turbulent storms and dark spots in Neptune's atmosphere, six new moons, Neptune's three rings, and the presence of frozen methane on Triton, as researchers at NASA's Jet Propulsion Laboratory describe Voyager's achievements.

1989-01-01

52

Optical Checkout of Large Antennas for Deep Space Probes  

Microsoft Academic Search

Optical measurements of the reflecting surface of deep space probes have proven to be one of the best methods of maintaining the necessary surface accuracy required. This type of checkout equipment is a necessary system for any deep space probe. The present optical checkout systems need to be improved, and with sufficient research they can be.

George W. Godfrey; E. W. McDonald; L. F. Hesse

1963-01-01

53

Voyager program. Voyager 1 encounter at Jupiter, 5 March 1979  

NASA Technical Reports Server (NTRS)

Highlights of Voyager 1 activity during the observatory and far-encounter phases are summarized. Daily sequence of events for the spacecraft during the period of greatest encounter activity (Feb. 26 through Mar. 7) the near-encounter phase is given. Times shown designate the time of signal reception at Deep Space Network stations. Events listed emphasize activities pertaining to the four remote sensing instruments on the scan platforms. However, the other 7 experiments will continuously collect data throughout the encounter period.

1979-01-01

54

Voyage of the Challenger  

NSDL National Science Digital Library

Learn more about the historic voyage of the H.M.S. Challenger. Scientists from all disciplines set out on December 21, 1872 for a four year research cruise to map the sea and its contents. This voyage paved the way for the development of marine biology, as we know it today. Site contains information on the instrumentation and laboratories used during the voyage and some of the important scientists that made the journey.

55

Voyager at Uranus: 1986  

NASA Technical Reports Server (NTRS)

The voyager 2 spacecraft begins its initial observations of Uranus November 4, 1985, and makes its final observation February 25, 1996. The data from the infrared interfermometer spectrometer, photopolarimeters, plasma wave, plasma detecter, and ultraviolet spectrometer will be processed to add a large block of infermation to the small amount already known. The trajectory of Voyager 2 is also discussed.

1986-01-01

56

Voyage to Jupiter.  

ERIC Educational Resources Information Center

This publication illustrates the features of Jupiter and its family of satellites pictured by the Pioneer and the Voyager missions. Chapters included are: (1) "The Jovian System" (describing the history of astronomy); (2) "Pioneers to Jupiter" (outlining the Pioneer Mission); (3) "The Voyager Mission"; (4) "Science and Scientsts" (listing 11…

Morrison, David; Samz, Jane

57

The Voyager flights to Jupiter and Saturn  

NASA Technical Reports Server (NTRS)

The results of the mini-Grand Tour to Jupiter and Saturn by the Voyager 1 and 2 spacecraft are highlighted. Features of the spacecraft are depicted including the 11 instruments designed to probe the planets and their magnetic environments, the rings of Saturn, the fleets of satellites escorting the planets, and the interplanetary medium. Major scientific discoveries relating to these phenomena are summarized.

1982-01-01

58

Médecine des voyages  

PubMed Central

Résumé Objectif Définir la pratique de la médecine des voyages, présenter les éléments fondamentaux d’une consultation complète préalable aux voyages à des voyageurs internationaux et aider à identifier les patients qu’il vaudrait mieux envoyer en consultation auprès de professionnels de la médecine des voyages. Sources des données Les lignes directrices et les recommandations sur la médecine des voyages et les maladies liées aux voyages publiées par les autorités sanitaires nationales et internationales ont fait l’objet d’un examen. Une recension des ouvrages connexes dans MEDLINE et EMBASE a aussi été effectuée. Message principal La médecine des voyages est une spécialité très dynamique qui se concentre sur les soins préventifs avant un voyage. Une évaluation exhaustive du risque pour chaque voyageur est essentielle pour mesurer avec exactitude les risques particuliers au voyageur, à son itinéraire et à sa destination et pour offrir des conseils sur les interventions les plus appropriées en gestion du risque afin de promouvoir la santé et prévenir les problèmes médicaux indésirables durant le voyage. Des vaccins peuvent aussi être nécessaires et doivent être personnalisés en fonction des antécédents d’immunisation du voyageur, de son itinéraire et du temps qu’il reste avant son départ. Conclusion La santé et la sécurité d’un voyageur dépendent du degré d’expertise du médecin qui offre le counseling préalable à son voyage et les vaccins, au besoin. On recommande à ceux qui donnent des conseils aux voyageurs d’être conscients de l’ampleur de cette responsabilité et de demander si possible une consultation auprès de professionnels de la médecine des voyages pour tous les voyageurs à risque élevé.

Aw, Brian; Boraston, Suni; Botten, David; Cherniwchan, Darin; Fazal, Hyder; Kelton, Timothy; Libman, Michael; Saldanha, Colin; Scappatura, Philip; Stowe, Brian

2014-01-01

59

Some Aspects of Satellite and Space Probe Reliability  

Microsoft Academic Search

It is becoming a recognized fact that many of the electronic piece parts used in present day ballistic missile and space probes are inadequate for the long-life space programs of the near future. Realization of the major differences of life and reliability requirements resulting from short and long term exposures to the space environment has led to a four point

T. W. Gross; H. C. Werner

1961-01-01

60

Aerodynamics problems of space probes in comet atmosphere  

Microsoft Academic Search

The paper deals with aerodynamic problems connected with a space probe moving in a rarefied gas-dust Halley's comet atmosphere on exposure to electromagnetic solar radiation. Their relative approach velocity will be 78 km\\/s.

Iu. A. Ryzhov; V. P. Bass; V. P. Kariagin; V. M. Kovtunenko; K. N. Kuzovkin

1985-01-01

61

Voyager 1 Image of Ganymede  

NASA Technical Reports Server (NTRS)

Voyager 1 took this picture of Ganymede from a distance of 1.6 million miles. Ganymede is Jupiter's largest satellite with a radius of approximately 2600 kilometers, about 1.5 times that of Earth's Moon. Ganymede is the seventh and largest of Jupiter's known satellites and is the third of the Galilean moons. Discovered in 1610 by Galileo and Marius, Ganymede is the largest satellite in the Solar System. It was named after the Greek mythical character, Ganymede, a handsome Trojan boy that Zeus took to Olympus to be a cupbearer for the gods (one of the only humans in Greek mythology who became immortal). Ganymede is larger than Mercury but has only half Mercury's mass. It has a bulk density of only two grams per cubic centimeter, almost half that of Earth's Moon. Ganymede is most likely composed of a mixture of rock and ice. The long white filaments resemble rays associated with impacts on the lunar surface. The various colors of different regions probably represent differing surface materials. Several dots of a single color (blue, green, and orange) on the picture are the result of markings on the camera used for pointing determinations and are not physical markings. Voyager scientists discovered that Ganymede has its own magnetosphere embedded inside Jupiter's large one. JPL manages and controls the Voyager Project for NASA's Office of Space Science.

1979-01-01

62

Voyages to Saturn  

NASA Technical Reports Server (NTRS)

The Voyager mission to Saturn is explained in detail. A history of Saturn observations from ancient times to the present is given. The Voyager spacecraft and their instruments are described. An overview of planetary astronomy is presented. The text is supplemented by numerous black and white and color photographs. The Saturn satellites are discussed in detail, and preliminary pictorial maps of the satellites are given.

Morrison, D.

1982-01-01

63

Novel Time Synchronization techniques for Deep Space Probes  

Microsoft Academic Search

New initiatives both for manned and unmanned exploration of the Moon and Mars have stimulated investigations on time synchronization due to its central role in communication, navigation and time stamping of scientific experiments. In the framework of the European Space Agency (ESA) project Novel Time Synchronization Techniques for Deep Space Probes (Syndee) two novel algorithms are proposed for locking a

E. Re; A. Di Cintio; G. Busca; D. Giunta; M. Sanchez

2009-01-01

64

Autonomy capabilities of European deep space probes  

Microsoft Academic Search

The European Space Agency ESA is currently preparing the two deep space missions, Huygens and Rosetta. This paper reviews the related requirements for autonomous operations in a poorly known environment. While for Huygens emphasis is on the control of the descent through Titan's atmosphere, for Rosetta the safe drilling of material samples in the microgravity environment of a comet is

Klaus Schilling; J. Lafontaine; Hubert Roth

1996-01-01

65

Black Hole Probes of Automorphic Space  

NASA Astrophysics Data System (ADS)

Over the past few years the arithmetic Langlands program has proven useful in addressing physical problems. In this paper it is shown how Langlands' reciprocity conjecture for automorphic forms, in combination with a representation theoretic notion of motives, suggests a framework in which the entropy of automorphic black holes can be viewed as a probe of spacetime that is sensitive to the geometry of the extra dimensions predicted by string theory. If it were possible to produce black holes with automorphic entropy in the laboratory their evaporation would provide us with information about the precise shape of the compact geometry.

Schimmrigk, Rolf

2012-10-01

66

Voyager Encounter Highlights  

NASA Technical Reports Server (NTRS)

The following are presented: computer animation of trajectories for both Voyagers 1 and 2; view of Jupiter during one orbit of Ganymede; computer animation of Voyager 2's encounter with Jupiter and its satellites; time lapse of the planet's rotation and its satellites; stroboscopic sequence of selected frames; cloud motion; Jupiter's Great Red Spot (4/25 - 5/24, 1979) through a violet filter; and the Great Red Spot through a blue filter by Voyager 1. The dynamics of Jupiter's clouds are shown - the whole planet is shown first, then two closer looks are repeated several times. Also included are pans of stills of Jupiter's satellites and a computer simulation tour of Saturn system from POV just behind Voyager, made of 116 images of Saturn through a green filter and of 516 images taken by Voyager 1 (9/12 - 9/14, 1980). Frames are enhanced to show the motion of features in Saturn's rings. Pans of stills of Saturn's satellites are shown. There is computer animation of the planet's system, rings, and Sigma Sagittari. Images on January 14, 1986 are through an orange filter. Uranus's satellites are shown as is computer animation of an August 1989 encounter.

1989-01-01

67

Solar system as space-probe  

Microsoft Academic Search

The characteristics of the movement of the solar system through space are examined and the possibility is considered that in their circulation around the Galaxy center the stars and clouds move through the spiral arms of the Galaxy. In such an event, the solar system would pass through interstellar clouds and the sun's luminosity would temporarily increase due to an

W. H. McCrea

1975-01-01

68

Participatory Sensing in Public Spaces: Activating Urban Surfaces with Sensor Probes  

E-print Network

Participatory Sensing in Public Spaces: Activating Urban Surfaces with Sensor Probes Stacey currency and political change. Keywords Participatory sensing, public spaces, urban probes INTRODUCTION and political discourse presents a new design space for enabling public participation and expression. We explore

Paulos, Eric

69

Has Voyager 1 left the heliosphere?  

NASA Astrophysics Data System (ADS)

In the past few years, scientists have vigorously debated the location of the Voyager 1 spacecraft: Has it left the Sun's vast heliosphere and reached interstellar space? Although the spacecraft has detected fewer and fewer accelerated particles, Gloeckler and Fisk note that magnetic field readings suggest it remains within the heliopause—a region that separates the heliosphere from the interstellar medium.

Wendel, JoAnna

2014-11-01

70

Voyager electronic parts radiation program, volume 1  

NASA Technical Reports Server (NTRS)

The Voyager spacecraft is subject to radiation from external natural space, from radioisotope thermoelectric generators and heater units, and from the internal environment where penetrating electrons generate surface ionization effects in semiconductor devices. Methods for radiation hardening and tests for radiation sensitivity are described. Results of characterization testing and sample screening of over 200 semiconductor devices in a radiation environment are summarized.

Stanley, A. G.; Martin, K. E.; Price, W. E.

1977-01-01

71

The Gulf Stream Voyage  

NSDL National Science Digital Library

The Gulf Stream Voyage is an online multidisciplinary project which utilizes both real time data and primary source materials to help guide students to discover the science and history of the Gulf Stream. Students will investigate this great ocean current, how it affects the Atlantic Ocean and some of mankind's experiences dealing with it. This voyage includes activities for marine science, earth science, chemistry, physics, biology, math, history and language arts. All may be easily used in today's technology enhanced classroom including access to real time ocean data, atmospheric data and historical primary source materials.

2000-01-01

72

Mission to Jupiter. [Pioneer 10 and 11 space probes  

NASA Technical Reports Server (NTRS)

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.

1975-01-01

73

Gravitational Experiments in Space: Gravity Probe B and STEP  

Microsoft Academic Search

We describe two space based gravitational physics experiments, the Gravity Probe B Relativity Mission (GPB) and the Satellite Test of the Equivalence Principle (STEP). GP-B will perform precision tests of two independent predictions of general relativity, the geodetic effect and frame dragging. STEP will provide a precision test of a foundation of general relativity, the Equivalence Principle.

J. Mester; S. Buchman; A. M. Cruise; D. Debra; H. Dittus; C. W. F. Everitt; B. Foulon; G. M. Keiser; B. J. Kent; J. Lipa; N. Lockerbie; J. M. Lockhart; F. Loeffler; B. Muhlfelder; B. Parkinson; C. Pegrum; M. Sandford; C. C. Speake; T. J. Sumner; M. Taber; R. Torii; P. Touboul; J. Turneaure; S. Vitale; W. Vodel; P. W. Worden

2004-01-01

74

The Evolving Space Weather System—Van Allen Probes Contribution  

NASA Astrophysics Data System (ADS)

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.

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

75

Van Allen Probes: Exploring the Extremes of Space Weather  

NSDL National Science Digital Library

This is a poster about radiation in space. Learners can read about the Van Allen belts and how NASA's Van Allen Probes are investigating the influence of the Sun's energy on Earth. The activity version also includes math problems, a vocabulary matching game, a communication research challenge, and a toolbox of web resources.

2013-07-14

76

Ocean Voyagers Lesson Plans  

NSDL National Science Digital Library

Ocean Voyagers is an educational outreach initiative consisting of an interdisciplinary curriculum program. It is designed to allow middle school teachers and students to gain real-world knowledge about oceanographic science, social science, maritime cultures, communication, literature, and the language arts. This collection features lesson plans on physical and biological oceanography, ecology, maritime heritage and culture.

77

Measurement of vacuum space potential by an emissive probe  

NASA Technical Reports Server (NTRS)

The use of an electron-emitting probe (Langmuir and Compton, 1931) to measure the space potential in the vacuum between parallel metal plates is demonstrated, extending the inflection-point interpretation technique of Smith et al. (1979) to the vacuum case. Measurements are made at the off half cycle of during half-wave-rectified sine-wave heating of 3-mm-long 30-micron-diameter W probes positioned with 1-mm precision between 18 x 23-cm Al or Cu plates 7.6 cm apart. The results are presented graphically: potentials of up to + or 30 V are measured with accuracy + or - 0.4 V.

Cho, M. H.; Chan, C.; Hershkowitz, N.; Intrator, T.

1984-01-01

78

VOYAGER OBSERVATIONS OF THE DIFFUSE FAR-ULTRAVIOLET RADIATION FIELD  

SciTech Connect

The two Voyager spacecraft have completed their planetary exploration mission and are now probing the outer realms of the heliosphere. The Voyager ultraviolet spectrometers continued to operate well after the Voyager 2 Neptune encounter in 1989. We present a complete database of diffuse radiation observations made by both Voyagers: a total of 1943 spectra (500-1600 A) scattered throughout the sky. These include observations of dust-scattered starlight, emission lines from the hot interstellar medium, and a number of locations where no diffuse radiation was detected, with the very low upper limit of about 25 photons cm{sup -2} s{sup -1} sr{sup -1} A{sup -1}. Many of these observations were from late in the mission when there was significantly less contribution from interplanetary emission lines and thus less contamination of the interstellar signal.

Murthy, Jayant [Indian Institute of Astrophysics, Bengalooru 560 034 (India); Henry, Richard Conn [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Holberg, Jay B., E-mail: jmurthy@yahoo.com [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States)

2012-03-01

79

Primary processing of magnetic field data aboard a space probe  

Microsoft Academic Search

The real-time processing of magnetometric data on a space probe is examined. The design and components of the three-component vector magnetometer used in this study are discussed. The on-board computer used to digitize the three signal components consists of: a processor; memory; and input, control, calibration, time, output, and interrupt ports. The functions of these components and the tasks of

D. Lenners; H. J. Linthe

1987-01-01

80

A Whaling Voyage  

NSDL National Science Digital Library

This activity relates a sailing ship's route to ocean currents. The route is taken from a true account of a whaling voyage on the ship Lucy Ann in 1847-1848. The ship sailed from Long Island, New York, to the Pacific, searching in different parts of the ocean, called "whaling grounds" where whales were known to be found at certain times of year. Since whaling vessels of that time were powered by sail, captains had to take advantage of predictable winds and currents to reach their destinations as quickly as possible. As sailors traveled throughout the worldâs oceans, they carefully recorded wind and sea conditions in logbooks, hour by hour. This information was assembled to plot the oceanâs prevailing winds and currents around the globe. In this activity students will plot the track of the whaling voyage of the Lucy Ann and relate it to wind direction and ocean currents.

81

Triton - Voyager's finale  

NASA Technical Reports Server (NTRS)

The investigation of the Neptunian satellite Triton by the Voyager 2 is described with interpretations of the object's nature and composition. The orbit, seasonal cycle, and southern-hemisphere solstice are described, and the composition of the satellite is discussed. Triton's mass and radius are known, and the objects is made up of about 70 percent rock and organics and 30 percent ice by mass. Triton's interior is warm and geologically active considering its distance from the sun, and large amounts of frozen methane and nitrogen are theorized to contribute to the object's high reflectivity. Also noted in the Voyager color images are creeping ice, cryogenic lava, and dark streaks on the south polar cap from nitrogen gas leaks driven by a type of greenhouse effect. Triton represents a class of satellite that has not been observed previously: a moon-sized body in a retrograde inclined orbit from the class of objects that coalesced to form Neptune.

Brown, R. H.

1992-01-01

82

Voyager: Giant Kelp  

NSDL National Science Digital Library

The Birch Aquarium at Scripps Institution of Oceanography offers this Web site as part of the Aquarium's online educational series, Voyager Science. Geared toward younger kids, this site introduces the kelp forest and related concepts with great photos, informative descriptions, and a few interactive activities. Giant Kelp focuses on the kelp plant itself, including the many (and often surprising) commercial uses of kelp products. Simple at-home experiments and online activities are also included.

Criqui, Nan

83

Voyager: The Sheltering Forest  

NSDL National Science Digital Library

The Birch Aquarium at Scripps Institution of Oceanography offers this Web site as part of the Aquarium's online educational series, Voyager Science. Geared toward younger kids, this site introduces the kelp forest and related concepts with great photos, informative descriptions, and a few interactive activities. The Sheltering Forest focuses on the many animals that make their home in the kelp forest, emphasizing the interdependence of organisms in the kelp ecosystem. Simple at-home experiments and online activities are also included.

Criqui, Nan

84

Voyager 1 'Blue Movie'  

NASA Technical Reports Server (NTRS)

This is the original Voyager 'Blue Movie' (so named because it was built from Blue filter images). It records the approach of Voyager 1 during a period of over 60 Jupiter days. Notice the difference in speed and direction of the various zones of the atmosphere. The interaction of the atmospheric clouds and storms shows how dynamic the Jovian atmosphere is.

As Voyager 1 approached Jupiter in 1979, it took images of the planet at regular intervals. This sequence is made from 66 images taken once every Jupiter rotation period (about 10 hours). This time-lapse movie uses images taken every time Jupiter longitude 68W passed under the spacecraft. These images were acquired in the Blue filter from Jan. 6 to Feb. 3 1979. The spacecraft flew from 58 million kilometers to 31 million kilometers from Jupiter during that time.

This time-lapse movie was produced at JPL by the Image Processing Laboratory in 1979.

2000-01-01

85

46 CFR Sec. 2 - Voyage numbers.  

Code of Federal Regulations, 2011 CFR

...with voyage No. 1 having the prefixed designation NSA and followed by the General Agents' abbreviated designation and voyage number, as NSA-1/ABC-1. (b) The continuity of NSA voyage numbers shall not change with berth...

2011-10-01

86

46 CFR Sec. 2 - Voyage numbers.  

Code of Federal Regulations, 2012 CFR

...with voyage No. 1 having the prefixed designation NSA and followed by the General Agents' abbreviated designation and voyage number, as NSA-1/ABC-1. (b) The continuity of NSA voyage numbers shall not change with berth...

2012-10-01

87

46 CFR Sec. 2 - Voyage numbers.  

...with voyage No. 1 having the prefixed designation NSA and followed by the General Agents' abbreviated designation and voyage number, as NSA-1/ABC-1. (b) The continuity of NSA voyage numbers shall not change with berth...

2014-10-01

88

46 CFR Sec. 2 - Voyage numbers.  

Code of Federal Regulations, 2010 CFR

...with voyage No. 1 having the prefixed designation NSA and followed by the General Agents' abbreviated designation and voyage number, as NSA-1/ABC-1. (b) The continuity of NSA voyage numbers shall not change with berth...

2010-10-01

89

46 CFR Sec. 2 - Voyage numbers.  

Code of Federal Regulations, 2013 CFR

...with voyage No. 1 having the prefixed designation NSA and followed by the General Agents' abbreviated designation and voyage number, as NSA-1/ABC-1. (b) The continuity of NSA voyage numbers shall not change with berth...

2013-10-01

90

Space Audio  

NSDL National Science Digital Library

This site offers the "sounds of space" processed from signals received by University of Iowa instruments on various spacecraft. The collection includes sounds from Saturn collected by the Cassini probe, sounds from the edge of the solar system collected by the Voyager probe, as well as radio bursts from solar flares and sounds created by Earth's magnetosphere. There are also descriptions of several types of sounds (whistlers, choruses, and auroral radio emissions) and sample sounds produced by processed data received from specific spacecraft (Galileo, Polar, Cassini, Cluster, and others).

91

Voyager 1 examines Jupiter  

NASA Technical Reports Server (NTRS)

An overview of the Voyager mission to Jupiter, Saturn, and possibly Uranus is presented. Scientific instruments onboard the spacecraft are described as well as methods used for their calibration and evaluation during the cruise phase of the mission. Experiments to be performed cover the following areas: imaging science, radio science, cosmic rays, ultraviolet spectroscopy, photopolarimetry, planetary radio astronomy, magnetic fields, low-energy charged particles, plasma science, and infrared radiometry and spectroscopy. A list of the satellites of Jupiter and their diameters, distances, and periods is included.

1979-01-01

92

Jules Verne Voyager, Jr.  

NSDL National Science Digital Library

This interactive map tool enables students and scientists to better understand the relationships between geophysical and geological processes, structures, and measurements with high-precision GPS data. It contains prepared images taken from the Jules Verne Voyager. Users can choose from a variety of base maps, add a number of geographic and geophysical overlays (e.g. plate boundaries, earthquake and volcano locations), and then superimpose crustal motion velocity vectors to observe how the tectonic plates move in relation to one another. The tool can be used to explore topics such as plate tectonics, seafloor spreading, and seasonal land and ocean productivity.

Chuck Meertens

93

IEC Thrusters for Space Probe Applications and Propulsion  

SciTech Connect

Earlier conceptual design studies (Bussard, 1990; Miley et al., 1998; Burton et al., 2003) have described Inertial Electrostatic Confinement (IEC) fusion propulsion to provide a high-power density fusion propulsion system capable of aggressive deep space missions. However, this requires large multi-GW thrusters and a long term development program. As a first step towards this goal, a progression of near-term IEC thrusters, stating with a 1-10 kWe electrically-driven IEC jet thruster for satellites are considered here. The initial electrically-powered unit uses a novel multi-jet plasma thruster based on spherical IEC technology with electrical input power from a solar panel. In this spherical configuration, Xe ions are generated and accelerated towards the center of double concentric spherical grids. An electrostatic potential well structure is created in the central region, providing ion trapping. Several enlarged grid opening extract intense quasi-neutral plasma jets. A variable specific impulse in the range of 1000-4000 seconds is achieved by adjusting the grid potential. This design provides high maneuverability for satellite and small space probe operations. The multiple jets, combined with gimbaled auxiliary equipment, provide precision changes in thrust direction. The IEC electrical efficiency can match or exceed efficiencies of conventional Hall Current Thrusters (HCTs) while offering advantages such as reduced grid erosion (long life time), reduced propellant leakage losses (reduced fuel storage), and a very high power-to-weight ratio. The unit is ideally suited for probing missions. The primary propulsive jet enables delicate maneuvering close to an object. Then simply opening a second jet offset 180 degrees from the propulsion one provides a 'plasma analytic probe' for interrogation of the object.

Miley, George H.; Momota, Hiromu; Wu Linchun; Reilly, Michael P. [Dept. of Nuclear, Plasma and Radiological Engineering, University of Illinois, Urbana, IL (United States); Teofilo, Vince L. [Lockheed Martin Space Systems Co., Advanced Technology Center, Palo Alto, CA (United States); Burton, Rodney [Dept. of Aerospace Engineering, University of Illinois, Urbana, IL (United States); Dell, Richard; Dell, Dick [Advanced Aerospace Resource Center (AARC), Raleigh, NC (United States); Hargus, William A. [Air Force Research Laboratory, Edwards AFB, CA 217-333-3772 (United States)

2009-03-16

94

Voyager Spacecraft Moves Towards Edge of Solar System  

NSDL National Science Digital Library

Traveling at 334 million miles per year, the Voyager 1 Spacecraft continues to return vast amounts of important astronomical data to researchers back on Earth, and has done so since its initial launch on September 5, 1977. Most recently, Voyager 1 has been in the news because it is rapidly approaching the boundary of the solar system, and will shortly reach interstellar space. Using measurements of the solar wind sent back from the craft, scientists at the Applied Physics Lab at Johns Hopkins University suggest that Voyager 1 has in fact already passed the terminal shock boundary that demarcates the transition from the solar system to interstellar space. Another piece of research conducted by a team of scholars at the University of Maryland suggest that Voyager 1 is nearing the termination shock boundary, but has yet to hit it. It is now estimated that Voyager 1 will reach the star next door to our own in about 40,000 years, though the spacecraft is thought to only have enough power to continue transmitting data until the year 2020. The first link will take visitors to a November 6, 2003 article in the Washington Post about the recent realization that the Voyager 1 will soon reach the end of the solar system. The second link leads to a joint press release released November 5, 2003 from the Jet Propulsion Laboratory in Pasadena, California and the Goddard Space Flight Center in Greenbelt, Maryland about the progress of the spacecraft. The third link leads to a rather comprehensive and intriguing website designed by NASA to provide the web-browsing public with material about the spacecraft. The site includes details about the technical specifications of the Voyager and a number of amazing images taken during its 26-year journey. The fourth link leads to an 8-page fact sheet provided by NASA that offers a nice overview of the spacecraft's mission and its observations of the other planets in the solar system, including Jupiter and Uranus. The fifth link will take visitors to the USGS Astrogeology homepage of the Voyager, which again provides yet another perspective on the important work of this spacecraft. The last link lets visitors learn about the Golden Record that is onboard the Voyager 1. Designed to convey a bit of information about the planet Earth to any other sentient life forms that the Voyager may encounter, the Record contains greetings from various political figures, such as Kurt Waldheim (the former secretary of the United Nations) and different samples of nature sounds and pieces of music.

Grinnell, Max

95

Take a Voyage of Discovery  

NSDL National Science Digital Library

On December 27, 1831, the H.M.S. Beagle left Plymouth Harbor for a round-the-world voyage. On board was would-be botanist Charles Darwin, the best tour guide biology has ever known. In 2009, we will celebrate Darwin's 200 th birthday and the 150 th anniversary of The Origin of Species publication. What better way to prepare for this celebration than to plan your own voyage of discovery this summer? As in summers past, we have once again asked the reviewers of NSTA Recommends to help you plan that voyage by suggesting the best summer reading for teachers.

Texley, Juliana

2008-07-01

96

GALILEO PROBE MEASUREMENTS OF D/H AND 3HE/4HE IN JUPITER'S ATMOSPHERE  

E-print Network

Goddard Space Flight Center, Greenbelt, MD 20771, USA Abstract. The Galileo Probe Mass Spectrometer to the mass peak at 3 amu. The D/H ratio is consistent with Voyager and ground based data and recent for D/H when compared with that for hydrogen in the local interstellar medium 1:6 0:12 10,5 implies

Atreya, Sushil

97

Electric Field Double Probe Measurements for Ionospheric Space Plasma Experiments  

NASA Technical Reports Server (NTRS)

Double probes represent a well-proven technique for gathering high quality DC and AC electric field measurements in a variety of space plasma regimes including the magnetosphere, ionosphere, and mesosphere. Such experiments have been successfully flown on a variety of spacecraft including sounding rockets and satellites. Typical instrument designs involve a series of trades, depending on the science objectives, type of platform (e.g., spinning or 3-axis stabilized), expected plasma regime where the measurements will be made, available telemetry, budget, etc. In general, ionospheric DC electric field instruments that achieve accuracies of 0.1 mV/m or better, place spherical sensors at large distances (10m or more) from the spacecraft body in order to extend well beyond the spacecraft wake and sheath and to achieve large signal-to-noise ratios for DC and long wavelength measurements. Additional sets of sensors inboard of the primary, outermost sensors provide useful additional information, both for diagnostics of the plasma contact potentials, which particularly enhance the DC electric field measurements on non-spinning spacecraft, and for wavelength and phase velocity measurements that use the spaced receiver or "interferometer" technique. Accurate attitude knowledge enables B times V contributions to be subtracted from the measured potentials, and permits the measured components to be rotated into meaningful geophysical reference frames. We review the measurement technique for both DC and wave electric field measurements in the ionosphere discussing recent advances involving high resolution burst memories, multiple baseline double probes, new sensor surface materials, biasing techniques, and other considerations.

Pfaff, R.

1999-01-01

98

Voyager to the Seventh Planet.  

ERIC Educational Resources Information Center

Presents recent findings obtained by the Voyager 2 mission on Uranus. Updates information on the planet's moons, rings, atmosphere, and magnetic field. Illustrations and diagrams of selected aspects of Uranus are included. (ML)

Gold, Michael

1986-01-01

99

The Voyager 2 Neptune encounter  

SciTech Connect

The findings made by the Voyager 2 Neptune encounter are reviewed. Data on the bowshock, magnetic field, magnetosphere, rings, plasma sheet, aurora, moons, and dust of Neptune are discussed. Findings made concerning Triton are summarized.

Tsurutani, B.T. (JPL, Pasadena, CA (USA))

1989-10-01

100

Planetary radio astronomy from Voyager  

NASA Technical Reports Server (NTRS)

The technique of radio astronomy makes it possible for a remote observer to detect the presence of magnetic fields and plasmas in planetary environments. Prior to the flights of the Voyager spacecraft, radio astronomical studies of Jupiter from earth and from earth orbit had correctly predicted the strength and orientation of Jupiter's magnetic field and trapped radiation belts. The Voyager Planetary Radio Astronomy investigations have now provided measurements of the complete spectrum of low frequency radio emissions from both planets. Each Voyager instrument consists of a pair of orthogonal, 10-m, electric monopole antennas which are connected to a step-tuned, superheterodyne receiver operating over the frequency range from 1.2 kHz to 40.5 MHz. The Voyager trajectory provided observations from above both the sunlit and nightside hemispheres of Jupiter. Saturn's nonthermal radio emission has been observed at frequencies as low as 3 kHz and as high as 1.2 MHz.

Alexander, J. K.

1983-01-01

101

Virtual Voyages for Introductory Oceanography  

NSDL National Science Digital Library

These Virtual Voyages were created as one-hour homework assignments for a freshman-level oceanography course at San Francisco State University (SFSU). Each voyage is structured around real-world images and includes five multiple-choice questions and five short-answer questions. Topics include seafloor bathymetry west of San Francisco, Earthquakes, Hawaiian hot spot, ocean waves, tides in San Francisco Bay, interaction of fresh and salt water in San Francisco Bay, ocean currents, sediments, and habitats for life.

Karen Grove

1998-12-10

102

Analysis of Alfvén eigenmodes in stellarators using non-evenly spaced probes  

Microsoft Academic Search

Eigenmodes play an important role in the dynamics of spatially extended systems. Using arrays of probes, it is possible to measure the spatial structure of experimentally observed fluctuations. But the interpretation of the measured data becomes very difficult if the number of probes is low, the probes are not evenly spaced or different sample rates are used. This is a

Stefan Zegenhagen; Andreas Werner; Arthur Weller; Thomas Klinger

2006-01-01

103

Floating Potential Probe Deployed on the International Space Station  

NASA Technical Reports Server (NTRS)

In the spring and summer of 2000, at the request of the International Space Station (ISS) Program Office, a Plasma Contactor Unit Tiger Team was set up to investigate the threat of the ISS arcing in the event of a plasma contactor outage. Modeling and ground tests done under that effort showed that it is possible for the external structure of the ISS to become electrically charged to as much as -160 V under some conditions. Much of this work was done in anticipation of the deployment of the first large ISS solar array in November 2000. It was recognized that, with this deployment, the power system would be energized to its full voltage and that the predicted charging would pose an immediate threat to crewmembers involved in extravehicular activities (EVA's), as well as long-term damage to the station structure, were the ISS plasma contactors to be turned off or stop functioning. The Floating Potential Probe was conceived, designed, built, and deployed in record time by a crack team of scientists and engineers led by the NASA Glenn Research Center in response to ISS concerns about crew safety.

Ferguson, Dale C.

2001-01-01

104

Magnetic field studies at Jupiter by Voyager 1: preliminary results  

Microsoft Academic Search

Results obtained by the Goddard Space Flight Center magnetometers on Voyager 1 concerning the large scale configuration of the Jovian bow shock and magnetopause, and the magnetic field in both the inner and outer magnetosphere are highlighted. There is evidence that a magnetic tail extending away from the planet on the nightside is formed by the solar wind-Jovian field interaction.

N. F. Ness; M. H. Acuna; R. P. Lepping; L. F. Burlaga; K. W. Behannon; F. M. Neubauer

1979-01-01

105

Imaging Narrow Angle The Voyager Spacecraft  

E-print Network

three times farther away from Earth and the Sun than is Pluto. The Voyagers are involved in a mis- sion for meeting several science objectives of NASA's Heliophysics System Observa- tory. The Voyagers are the only

Waliser, Duane E.

106

The Voyage of the Odyssey  

NSDL National Science Digital Library

PBS Online presents the Ocean Alliance's Voyage of the Odyssey, a multi-year project that is gathering baseline data on ocean health, using whales, albatrosses, and pelagic fish as environmental indicators. Students can read or listen to daily logs from the ship and track the voyage, while Science from the Field offers several video and audio reports. Be sure not to pass by the Interactive Ocean portion of the site, which offers a unique opportunity to experience some of the sights and sounds beneath the surface. The Class from the Sea section is still under construction but will offer exciting ways to interact with the voyage, including virtual teleconferencing with the ship's crew. This site is a cool multimedia resource for captivating the attention of students and also a more general audience.

2002-01-01

107

The Voyage of the Beagle  

NSDL National Science Digital Library

As part of Knowledge Matters' useful Online Literature Library, interested viewers may now access the full text of Charles Darwin's work The Voyage of the Beagle. From St. Jago and the Cape de Verd Islands to Mauritius and back to England, Darwin describes the voyage (and his thoughts on evolution) herein. The text is reproduced in full, and includes hyperlinked references and footnotes. Students may also access The Origin of Species and The Descent of Man (web version still in process) by clicking on Darwin's name.

Darwin, Charles, 1809-1882.

1999-01-01

108

46 CFR 80.15 - Ocean voyage.  

...Shipping 3 2014-10-01 2014-10-01 false Ocean voyage. 80.15 Section 80.15 Shipping...SAFETY STANDARDS AND COUNTRY OF REGISTRY § 80.15 Ocean voyage. An ocean voyage for the purposes of this part means:...

2014-10-01

109

46 CFR 80.15 - Ocean voyage.  

Code of Federal Regulations, 2011 CFR

...Shipping 3 2011-10-01 2011-10-01 false Ocean voyage. 80.15 Section 80.15 Shipping...SAFETY STANDARDS AND COUNTRY OF REGISTRY § 80.15 Ocean voyage. An ocean voyage for the purposes of this part means:...

2011-10-01

110

46 CFR 80.15 - Ocean voyage.  

Code of Federal Regulations, 2012 CFR

...Shipping 3 2012-10-01 2012-10-01 false Ocean voyage. 80.15 Section 80.15 Shipping...SAFETY STANDARDS AND COUNTRY OF REGISTRY § 80.15 Ocean voyage. An ocean voyage for the purposes of this part means:...

2012-10-01

111

46 CFR 80.15 - Ocean voyage.  

Code of Federal Regulations, 2010 CFR

...Shipping 3 2010-10-01 2010-10-01 false Ocean voyage. 80.15 Section 80.15 Shipping...SAFETY STANDARDS AND COUNTRY OF REGISTRY § 80.15 Ocean voyage. An ocean voyage for the purposes of this part means:...

2010-10-01

112

46 CFR 80.15 - Ocean voyage.  

Code of Federal Regulations, 2013 CFR

...Shipping 3 2013-10-01 2013-10-01 false Ocean voyage. 80.15 Section 80.15 Shipping...SAFETY STANDARDS AND COUNTRY OF REGISTRY § 80.15 Ocean voyage. An ocean voyage for the purposes of this part means:...

2013-10-01

113

Voyager to Jupiter and Saturn  

NASA Technical Reports Server (NTRS)

The NASA Voyager mission to explore planets of the outer solar system is summarized. The mission schedule and profiles for encounters with Jupiter and Saturn, and possibly with Uranus and Pluto are included along with a description of the spacecraft and its trajectories. Scientific investigations to be made and the instruments carried are also discussed.

1977-01-01

114

november 2009 Darwin Virtual Voyage  

E-print Network

, an art show on UC's campus celebrating Charles Darwin's legacy through linkages of science and artResearchUC november 2009 Darwin Virtual Voyage 4-D | Fashion Annual Report Edition #12;UC Wel. Darwin-inspired works-- almost all created specifically for the show--highlighted Darwin's theory

Papautsky, Ian

115

Space-Based Passing Time Estimation on a Freeway Using Cell Phones as Traffic Probes  

Microsoft Academic Search

This paper examines the usability of mobile cellular networks to obtain traffic information on a freeway. The question of whether a mobile station (cell phone) can play an acceptable role as a probe for collecting traffic information on a freeway is examined. A space-based approach, wherein the probe vehicles transmit information to roadside devices as they pass through reference points,

Keemin Sohn; Keeyeon Hwang

2008-01-01

116

Has Voyager 1 really crossed the heliopause?  

NASA Astrophysics Data System (ADS)

The Voyager 1 spacecraft is currently in the vicinity of the heliopause, which separates the heliosphere from the local interstellar medium. There has been a precipitous decrease in particles accelerated in the heliosphere, and a substantial increase in galactic cosmic rays (GCRs). The evidence is unclear, however, as to whether Voyager 1 has crossed the heliopause into the local interstellar medium, or remains within the heliosheath. In this paper we propose a test that will determine whether Voyager 1 has crossed the heliopause: If Voyager 1 remains in the heliosheath, the high plasma densities must be due to compressed solar wind, with the consequence that Voyager 1 will encounter another current sheet, where the polarity of the magnetic field reverses. Voyager 1 observations can be used to predict that the next current sheet crossing is likely to occur during 2015. A prediction is also provided as to what the Voyager 2 plasma detector will measure in the next few years.

Gloeckler, G.; Fisk, L. A.

2015-01-01

117

Early Results from the Floating Potential Probe on the International Space Station  

NASA Technical Reports Server (NTRS)

This viewgraph presentation provides information on the Floating Potential Probe (FPP) on the International Space Station (ISS). The FPP measures the body voltage (electric potential) of the, and the measurements are then transmitted to Earth.

Morton, Thomas L.; Ferguson, Dale C.

2001-01-01

118

Enabling interstellar probe  

NASA Astrophysics Data System (ADS)

The scientific community has advocated a scientific probe to the interstellar medium for over 30 years. While the Voyager spacecraft have passed through the termination shock of the solar wind, they have limited lifetimes as their radioisotope power supplies decay. It remains unclear whether they can reach the heliopause, the boundary between shocked solar wind and interstellar plasmas, and, in any case, they will not reach the undisturbed interstellar medium. As with most exploratory space missions, their ongoing observations continue to raise even more questions about the nature of the interaction of our heliosphere and the interstellar medium. Scientific questions including: What is the nature of the nearby interstellar medium? How do the Sun and galaxy affect the dynamics of the heliosphere? What is the structure of the heliosphere? How did matter in the solar system and interstellar medium originate and evolve? can only be answered by an "interstellar precursor" probe. Such a mission is required to make in situ measurements in the interaction region and interstellar medium itself at distances far from the Sun, but in a finite mission lifetime. By launching a probe toward the incoming "interstellar wind," whose direction is known, the distance to be traveled can be minimized but is still large. The current consensus is that a scientifically compelling mission must function to at least a distance of 200 astronomical units (AU) from the Sun and return a reasonable stream of data during the voyage. The central problem is that of providing a means of propulsion to accelerate a probe from the Solar System. Even with a low-mass payload and spacecraft, achieving the high speeds needed, even with gravity assists, have remained problematic. Voyager 1, the fastest object ever to leave the system is now traveling ˜3.6 AU/yr, and a credible probe must reach at least 2-3 times this speed. The use of an Ares V is an approach for enabling a fast interstellar precursor mission. Maximum capability uses the combination of an Ares V, two-engine Centaur upper stage, close fly-by of Jupiter, and radioisotope electric propulsion (REP). Deletion of any of these pieces does not disable the mission, but does increase the flyout time to a given distance. This approach is more robust and provides a faster probe than an earlier alternative, designed for launch by a Delta IV 4050H plus twin Star 48A upper stages.

McNutt, Ralph L.; Wimmer-Schweingruber, Robert F.; International Interstellar Probe Team

2011-04-01

119

Data link relay design. [space probe with entry at Uranus  

NASA Technical Reports Server (NTRS)

The data link for the Ames baseline probe as applied to the MJU spacecraft specifically with an entry at Uranus is analyzed. A frequency analysis, a trajectory analysis, and a discussion of the effects on the spacecraft design by the data link are presented. The possibilities of a two-way link are considered.

Parsons, P.

1974-01-01

120

Voyager: The grandest tour. The mission to the outer planets  

NASA Technical Reports Server (NTRS)

A history and general accomplishments of the Voyager 1 and 2 missions to the outer planets are presented. Over the course of 12 years, these spacecraft drew back the curtain on nearly half the solar system. They brought into sharp focus the faces of the four giant outer planets - Jupiter, Saturn, Uranus, and Neptune - and their families of disparate moons. The Voyagers showed us unimagined worlds: frozen beauty in the rings of Saturn, and molten violence in the explosive sulfur volcanoes on Jupiter's moon Io. They brought us close-ups of the florid and intricate storms of Jupiter itself. Voyager 2 went on to reveal the peculiarities of cockeyed Uranus and its equally skewed rings and moons. Then finally, Neptune, nearly invisible from earth, was unveiled in all its big, blue splendor, circled by shadowy rings and a bright pastel moon called Triton. Both Voyagers are headed toward the outer boundary of the solar system in search of the heliopause, the region where the sun's influence wanes and the beginning of interstellar space can be sensed.

1991-01-01

121

Changes around Marduk between Voyager, and Galileo's first two orbits  

NASA Technical Reports Server (NTRS)

Detail of changes around Marduk on Jupiter's moon Io as seen by Voyager 1 in 1979 (upper left) and NASA's Galileo spacecraft between June 1996 (lower left) and September 1996 (upper and lower right). The new dark red linear feature extending southeast from Marduk is about 250 kilometers long and may be a volcanic fissure. The flow-like feature at the bottom of the images is distinct in the Voyager data, indistinct in the June Galileo data, but distinct again in the September Galileo data. This may be due to the different lighting conditions rather than volcanic activity. The Voyager 1 image uses the green, blue, and violet filters. The upper right September 1996 image from Galileo uses the violet and green filters of the solid state imaging system aboard the Galileo spacecraft and a synthetic blue to simulate Voyager colors. The lower June and September, 1996 Galileo images use the imaging system's near-infrared (756 nm), green, and violet filters. North is to the top in all frames.

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

1996-01-01

122

Radio science investigations with Voyager  

NASA Technical Reports Server (NTRS)

Radio links to and from the Voyager spacecraft will be used for occultation measurements of planetary and satellite atmospheres and ionospheres, the rings of Saturn, the solar corona, and the general-relativistic time delay for radio wave propagation through the solar gravity field. In addition, the radio link measurements may provide information on the gravity fields of the planets, the masses of the satellites, properties of the interplanetary medium, and long-wavelength gravitational radiation propagation in the solar system.

Eshleman, V. R.; Tyler, G. L.; Anderson, J. D.; Fjeldbo, G.; Levy, G. S.; Wood, G. E.; Croft, T. A.

1977-01-01

123

Take a Voyage of Discovery  

ERIC Educational Resources Information Center

On December 27, 1831, the "H.M.S. Beagle" left Plymouth Harbor for a round-the-world voyage. On board was would-be botanist Charles Darwin, the best tour guide biology has ever known. In 2009, we will celebrate Darwin's 200th birthday and the 150th anniversary of "The Origin of Species" publication. What better way to prepare for this celebration…

Texley, Juliana

2008-01-01

124

Applications of Doppler Measurements to Problems in Relativity, Space Probe Tracking, and Geodesy  

Microsoft Academic Search

This paper begins with a discussion of the precision with which the Doppler shift in the signal received from a space vehicle can be measured, using existing atomic frequency standards on the ground, and a proposed transponder system on the vehicle. Applications of Doppler methods to measuring the gravitational redshift, to tracking space probes and measuring certain astronomical constants, and

Robert Newton

1960-01-01

125

MARINER 9 SPACE PROBE UNDERGOES FINAL CHECKS PRIOR TO ENCAPSULATION  

NASA Technical Reports Server (NTRS)

A technician checks the Mariner I spacecraft prior to its encapsulation for launch to Mars. An Atlas-Centaur rocket successfully launched the mars-bound spacecraft from Cape Kennedy at 6:23 p.m. EDT, May 30, 1971. Designated Mariner 9 following launch, the probe will arrive at Mars in mid-November. It will transmit scientific data about that planet's surface and atmosphere.

1971-01-01

126

Vacuum Fluctuations as Quantum Probes in FRWL space-times  

E-print Network

Vacuum fluctuations related a massless conformally coupled scalar field in Friedman-Robertson-Walker-Lemaitre (FRWL) space-times are investigated. Point-slitting regularization is used and a specific renormalization proposal is discussed. Applications to generic black holes and FRWL form of the de Sitter space-time are presented.

Sergio Zerbini

2014-11-03

127

Voyage of Discovery - Duration: 1:35.  

NASA Video Gallery

These animations show NASA's Voyager spacecraft encountering Jupiter, Saturn, Uranus and Neptune on their grand tour through the solar system. The artist's renderings were made based on navigationa...

128

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

NASA Technical Reports Server (NTRS)

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.

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

2010-01-01

129

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

130

Probing chemical space with alkaloid-inspired libraries.  

PubMed

Screening of small-molecule libraries is an important aspect of probe and drug discovery science. Numerous authors have suggested that bioactive natural products are attractive starting points for such libraries because of their structural complexity and sp(3)-rich character. Here, we describe the construction of a screening library based on representative members of four families of biologically active alkaloids (Stemonaceae, the structurally related cyclindricine and lepadiformine families, lupin and Amaryllidaceae). In each case, scaffolds were based on structures of the naturally occurring compounds or a close derivative. Scaffold preparation was pursued following the development of appropriate enabling chemical methods. Diversification provided 686 new compounds suitable for screening. The libraries thus prepared had structural characteristics, including sp(3) content, comparable to a basis set of representative natural products and were highly rule-of-five compliant. PMID:24451589

McLeod, Michael C; Singh, Gurpreet; Plampin, James N; Rane, Digamber; Wang, Jenna L; Day, Victor W; Aubé, Jeffrey

2014-02-01

131

Probing chemical space with alkaloid-inspired libraries  

NASA Astrophysics Data System (ADS)

Screening of small-molecule libraries is an important aspect of probe and drug discovery science. Numerous authors have suggested that bioactive natural products are attractive starting points for such libraries because of their structural complexity and sp3-rich character. Here, we describe the construction of a screening library based on representative members of four families of biologically active alkaloids (Stemonaceae, the structurally related cyclindricine and lepadiformine families, lupin and Amaryllidaceae). In each case, scaffolds were based on structures of the naturally occurring compounds or a close derivative. Scaffold preparation was pursued following the development of appropriate enabling chemical methods. Diversification provided 686 new compounds suitable for screening. The libraries thus prepared had structural characteristics, including sp3 content, comparable to a basis set of representative natural products and were highly rule-of-five compliant.

McLeod, Michael C.; Singh, Gurpreet; Plampin, James N.; Rane, Digamber; Wang, Jenna L.; Day, Victor W.; Aubé, Jeffrey

2014-02-01

132

Probing Chemical Space with Alkaloid-Inspired Libraries  

PubMed Central

Screening of small molecule libraries is an important aspect of probe and drug discovery science. Numerous authors have suggested that bioactive natural products are attractive starting points for such libraries, due to their structural complexity and sp3-rich character. Here, we describe the construction of a screening library based on representative members of four families of biologically active alkaloids (Stemonaceae, the structurally related cyclindricine and lepadiformine families, lupin, and Amaryllidaceae). In each case, scaffolds were based on structures of the naturally occurring compounds or a close derivative. Scaffold preparation was pursued following the development of appropriate enabling chemical methods. Diversification provided 686 new compounds suitable for screening. The libraries thus prepared had structural characteristics, including sp3 content, comparable to a basis set of representative natural products and were highly rule-of-five compliant. PMID:24451589

McLeod, Michael C.; Singh, Gurpreet; Plampin, James N.; Rane, Digamber; Wang, Jenna L.; Day, Victor W.; Aubé, Jeffrey

2014-01-01

133

New developments at Hunveyor and Husar space probe model constructions in Hungarian Universities and Colleges: status report of 2008  

NASA Astrophysics Data System (ADS)

Introduction Hunveyor and Husar space probe models are the main school robotics program in Hungary in the last decade initiated by our Cosmic Materials Space research Group (CMSRG). As a new form of planetary science education in Hungary students build their lander and rover robots and test them on test tables, carry out simulations, and go with their instruments to field works of planetary geology analog sites. Recently 10 groups work in this program and here is a status report about the new results. Planetary robot construction and simulations steps We summarized in 10 steps the main "constructional and industrial research and technology" description of planetary material studying and collecting by space probes (landers, rovers). We focused on the activity we began and teach to carry out at those steps. (Main planets considered were the Moon and Mars): 1. Reconnaissance and survey of the surface of a planet by orbital space probes (i.e. Lunar Orbiter, MGS, MRO etc.) Our studies: photogeology, geomorphology, preparations to cartography. 2. Mapping of the surface of the selected planet with geographical and stratigraphical methods. We (CMSRG) prepared thematic maps on Moon, Mercury, Mars, Venus [1] and Atlas (3) in the series [2,3]. 3. Identification of various surface materials by albedo, spectroscopic [4], thermal IR, identification and selection of the target sites. (in terrestrial analog sites during field works) 4. Planning the space probe system lander and rover working together (MPF-Sojourner type assembly). Planning of the Hunveyor and Husar models. 5. Construction and manufacturing lander and rover units. All Hunveyor groups built their models [5]. 6. Launching and traveling the space probes to the planetary surface. (No rocket building, we simulate [6] some events during the voyage only). 7. Measuring the planetary surface environment on the surface of target planet [7]. (CMSRG) groups carry out test-table measurements [8] and simulations, and later they go to geological type planetary analog field works in terrestrial conditions [9]. 8. Transmitting data. At CMSRG groups at field observations to the "terrestrial control" receives data. 9. Studies on planetary material samples. We can study real NASA Lunar Sample, real Hungarian and NIPR meteorite samples. 10. Comparative planetology. CMSRG's outreach studies are summarized in the Concise atlas series notebooks. Husar-2 rover developments The Husar-2 developments of the Pécs University were focused on a rover type to use it in the MDRS program. After systematic developments of Husars from LEGO Husar till the Husar-2a, -2b, -2c variants the final version Husar-2d visited the MDRS crew 71. in Utah, USA in 2008. Two years ago H. Hargitai used Husar-2b in Utah, in the works of the MRDS crew 42. where dry badlands surface forms are excellent analogs to Martian landscape. Hunveyor-4 ice surface visitor The new developments in Hunveyor-4 focused on the winter Balaton surface measurements. The triangular arrangement for the measuring arrangement of the three sound frequency range sensors with a hanged on hydrophone was planned [7]. Husar-5 developments The Husar-5 developments focused on LEGO modelling, and one measurement is for soil vibrations, the other is for the conductivity of the soil. It is in construction at Széchenyi István High School, Sopron. Husar-6 developments The Husar-6 is another LEGO based modelling, built at Zsigmondy Vilmos High School, Dorog. Hunveyor-9 and Husar-9 It is one of the newest construction at the Eötvös József High School in Tata. The Hunveyor-9 have been built with camera and a telescopic arm instrumentation, and a magnetic carpet experiment. Magnetic carpet is a sensor of the magnetic components of a planetary dust mixture transported by the wind. The mixing ratio of the magnetic and nonmagnetic components were measured with various slope angles of the carpet unrolled from Hunveyor-9. Hunveyor-10 The Neumann János Computer Science Society developed the last Hunveyor system. It was a meteorological station w

Hegzi, S.; Bérczi, Sz.; Hudoba, Gy.; Magyar, I.; Lang, A.; Istenes, Z.; Weidinger, T.; Tepliczky, I.; Varga, T.; Hargitai, H.

2008-09-01

134

Voyager at Neptune - A preliminary report  

SciTech Connect

Data obtained from the Voyager mission to Neptune are discussed. The atmosphere and magnetosphere of Neptune are described. Specific attention is given to Neptune's Great Dark Spot and its systems of thin, dark rings. The Voyager data regarding Neptune's satellites, in particular Triton and Nereid, are examined.

Kaufmann, W.J. (San Diego State Univ., CA (USA) Illinois Univ., Urbana (USA))

1989-12-01

135

The Atmosphere of Jupiter: An Analysis of the Voyager Radio Occultation Measurements  

Microsoft Academic Search

Coherently related S (2.3 GHz) and X band (8.4 GHz) signals transmitted from Voyager 1 and 2 have been used to probe the Jovian atmosphere during occultations of the spacecraft by Jupiter. The observations have yielded profiles in height of the gas refractivity, molecular number density, pressure, temperature, and microwave absorption in the troposphere and stratosphere of Jupiter at latitudes

G. F. Lindal; G. E. Wood; G. S. Levy; J. D. Anderson; D. N. Sweetnam; H. B. Hotz; B. J. Buckles; D. P. Holmes; P. E. Doms; V. R. Eshleman; G. L. Tyler; T. A. Croft

1981-01-01

136

Voyager 2 plasma observations in the heliosheath  

NASA Astrophysics Data System (ADS)

Voyager 2 is now 20 AU deep into the heliosheath; if the width is similar to that in the Voyager 1 direction it is 2/3 of the way to the heliopause. We present recent observations, compare with observations from Voyager 1, and compare with model predictions. The speed of the flows observed by Voyager 2 in the heliosheath have been, on average, remarkably constant at 150 km/s. The flow angle has changed dramatically, however, and is now 60 degrees from radial, with more of the turning occurring in the RT than RN planes. After 2011, the average density and temperature of the plasma have also not changed. These flows are very different than at V1, where the speed was always below 100 km/s and decreased across the heliosheath. Models predict VR at Voyager 2 well, the the flow angle predictions differ from the observations.

Richardson, John

137

Voyager Briefing: Expectations of the Neptune Encounter  

NASA Astrophysics Data System (ADS)

This NASA KSC video release presents a news briefing held Aug. 4, 1989 at NASA Headquarters three weeks after Voyager 2's official "encounter" with Neptune began. The video is comprised of two slide presentations followed by a short question and answer period. The press conference is moderated by Charles Redmond, (NASA Public Affairs), includes an introduction by Dr. Geoffrey A Briggs (Dir., Solar System Exploration Div.), and features Norman R. Haynes (Voyager Project Manager, JPL) and Dr. Edward C. Stone (Voyager Project Scientist, Cal Tech). Mr. Haynes' presentation centers on Voyager's history, engineering changes, and spacecraft trajectories while Dr. Stone presents the scientific aspects of Voyager, including the 11 scientific investigations planned for the mission, instruments used, and imaging techniques.

1989-08-01

138

Voyager Briefing: Expectations of the Neptune Encounter  

NASA Technical Reports Server (NTRS)

This NASA KSC video release presents a news briefing held Aug. 4, 1989 at NASA Headquarters three weeks after Voyager 2's official "encounter" with Neptune began. The video is comprised of two slide presentations followed by a short question and answer period. The press conference is moderated by Charles Redmond, (NASA Public Affairs), includes an introduction by Dr. Geoffrey A Briggs (Dir., Solar System Exploration Div.), and features Norman R. Haynes (Voyager Project Manager, JPL) and Dr. Edward C. Stone (Voyager Project Scientist, Cal Tech). Mr. Haynes' presentation centers on Voyager's history, engineering changes, and spacecraft trajectories while Dr. Stone presents the scientific aspects of Voyager, including the 11 scientific investigations planned for the mission, instruments used, and imaging techniques.

1989-01-01

139

IEC Thrusters for Space Probe Applications and Propulsion  

Microsoft Academic Search

Earlier conceptual design studies (Bussard, 1990; Miley et al., 1998; Burton et al., 2003) have described Inertial Electrostatic Confinement (IEC) fusion propulsion to provide a high-power density fusion propulsion system capable of aggressive deep space missions. However, this requires large multi-GW thrusters and a long term development program. As a first step towards this goal, a progression of near-term IEC

George H. Miley; Hiromu Momota; Linchun Wu; Michael P. Reilly; Vince L. Teofilo; Rodney Burton; Richard Dell; William A. Hargus

2009-01-01

140

Improved concatenated coding\\/decoding for deep space probes  

Microsoft Academic Search

Coding and decoding alternatives to improve the energy efficiency of the concatenated Reed-Solomon (RS) convolutional coding scheme used in deep space missions, as recommended by the CCSDS, are discussed. It is shown via decoder simulations that a nonuniform RS code profile, combined with state pinning in the inner trellis decoder, can improve performance about 0.6 dB at Pb=10-3 relative to

Dale C. Linne von Berg; Stephen G. Wilson

1992-01-01

141

Probing Planckian physics in de Sitter space with quantum correlations  

NASA Astrophysics Data System (ADS)

We study the quantum correlation and quantum communication channel of both free scalar and fermionic fields in de Sitter space, while the Planckian modification presented by the choice of a particular ?-vacuum has been considered. We show the occurrence of degradation of quantum entanglement between field modes for an inertial observer in curved space, due to the radiation associated with its cosmological horizon. Comparing with standard Bunch-Davies choice, the possible Planckian physics causes some extra decrement on the quantum correlation, which may provide the means to detect quantum gravitational effects via quantum information methodology in future. Beyond single-mode approximation, we construct proper Unruh modes admitting general ?-vacua, and find a convergent feature of both bosonic and fermionic entanglements. In particular, we show that the convergent points of fermionic entanglement negativity are dependent on the choice of ?. Moreover, an one-to-one correspondence between convergent points Hc of negativity and zeros of quantum capacity of quantum channels in de Sitter space has been proved.

Feng, Jun; Zhang, Yao-Zhong; Gould, Mark D.; Fan, Heng; Sun, Cheng-Yi; Yang, Wen-Li

2014-12-01

142

Oberon at Voyager Closest Approach  

NASA Technical Reports Server (NTRS)

This Voyager 2 picture of Oberon is the best the spacecraft acquired of Uranus' outermost moon. The picture was taken shortly after 3:30 a.m. PST on Jan. 24, 1986, from a distance of 660,000 kilometers (410,000 miles). The color was reconstructed from images taken through the narrow-angle camera's violet, clear and green filters. The picture shows features as small as 12 km (7 mi) on the moon's surface. Clearly visible are several large impact craters in Oberon's icy surface surrounded by bright rays similar to those seen on Jupiter's moon Callisto. Quite prominent near the center of Oberon's disk is a large crater with a bright central peak and a floor partially covered with very dark material. This may be icy, carbon-rich material erupted onto the crater floor sometime after the crater formed. Another striking topographic feature is a large mountain, about 6 km (4 mi) high, peeking out on the lower left limb. The Voyager project is managed for NASA by the Jet Propulsion Laboratory.

1986-01-01

143

Means to remove electrode contamination effect of Langmuir probe measurement in space  

SciTech Connect

Precaution to remove the serious effect of electrode contamination in Langmuir probe experiments has not been taken in many space measurements because the effect is either not understood or ignored. We stress here that one should pay extra attention to the electrode contamination effect to get accurate and reliable plasma measurements so that the long time effort for sounding rocket/satellite missions does not end in vain or becomes less fruitful. In this paper, we describe two main features of voltage-current characteristic curves associated with the contaminated Langmuir probe, which are predicted from the equivalent circuit model, which we proposed in 1970's. We then show that fast sweeping dc Langmuir probes can give reliable results in the steady state regime. The fast sweeping probe can also give reliable results in transient situations such as satellite moves through plasma bubble in the ionosphere where the electron density drastically changes. This fact was first confirmed in our laboratory experiment.

Oyama, K.-I.; Lee, C. H.; Fang, H. K.; Cheng, C. Z. [Plasma and Space Science Center, National Cheng Kung University, No.1 Ta-Hsueh Rd., Tainan 70101, Taiwan (China)

2012-05-15

144

Means to remove electrode contamination effect of Langmuir probe measurement in space.  

PubMed

Precaution to remove the serious effect of electrode contamination in Langmuir probe experiments has not been taken in many space measurements because the effect is either not understood or ignored. We stress here that one should pay extra attention to the electrode contamination effect to get accurate and reliable plasma measurements so that the long time effort for sounding rocket/satellite missions does not end in vain or becomes less fruitful. In this paper, we describe two main features of voltage-current characteristic curves associated with the contaminated Langmuir probe, which are predicted from the equivalent circuit model, which we proposed in 1970's. We then show that fast sweeping dc Langmuir probes can give reliable results in the steady state regime. The fast sweeping probe can also give reliable results in transient situations such as satellite moves through plasma bubble in the ionosphere where the electron density drastically changes. This fact was first confirmed in our laboratory experiment. PMID:22667663

Oyama, K-I; Lee, C H; Fang, H K; Cheng, C Z

2012-05-01

145

Space probe/satellite ejection apparatus for spacecraft  

NASA Technical Reports Server (NTRS)

An ejection apparatus for spinning and propelling objects for ejection from a spacecraft at a desired velocity and rotational speed is discussed. The apparatus includes a launch cradle on which the space object to be ejected rests. The cradle is rotatably supported by a central hub secured to the upper end of the pneumatic cylinder piston shaft. Release mechanisms consisting of a retractable pin and locking lug is utilized to hold the cradle and object to be ejected. The release mechanism has a fixed barrier member which holds the retractable pin in engagement with the locking lug until release by upward movement of the launch cradle beyond the barrier height.

Smyly, H. M.; Miller, C. D.; Cloyd, R. A.; Heller, C. (inventors)

1984-01-01

146

MARINER 8 SPACE PROBE UNDERGOES INSTALLATION OF SOLAR ARRAYS  

NASA Technical Reports Server (NTRS)

Technicians install solar panels aboard the mariner H spacecraft in a cleanroom facility at Cape Kennedy. The spacecraft will orbit Mars following a seven-month journey from Earth. Designed to function 90 days, the spacecraft, which will be designated Mariner 8 following launch, will provide data about the Red Planet's atmospheric and surface characteristics. Mariner Mars H will be launched aboard an Atlas-Centaur space vehicle no earlier than May 7, 1971, from Cape Kennedy's Launch Complex 36A. A second Mariner Mars spacecraft will be launched 10 days later.

1971-01-01

147

MARINER 8 SPACE PROBE'S SOLAR ARRAYS ARE INSTALLED  

NASA Technical Reports Server (NTRS)

Technicians prepare to install a solar panel on the Mariner H spacecraft in preparation for its launch to Mars, no earlier than May 7, 1971. The spacecraft will be launched aboard an Atlas Centaur space vehicle from Cape Kennedy's Complex 36A, and will go into orbit around Mars at the completion of a seven-month journey from Earth. It is designed to operate 90 days and return data about the planet's atmospheric and surface characteristics. Following launch, the spacecraft will be designated Mariner 8. A second Mariner Mars spacecraft is scheduled to be launched 10 days later.

1971-01-01

148

Space probe/satellite ejection apparatus for spacecraft  

NASA Technical Reports Server (NTRS)

An ejection apparatus for spinning and propelling objects for ejection from a spacecraft at a desired velocity and rotational speed is discussed. The apparatus includes a launch cradle on which the space object to be ejected rests. The cradle is rotatably supported by a central hub secured to the upper end of the pneumatic cylinder piston shaft. Release mechanisms consisting of a retractable pin and locking lug is utilized to hold the cradle and object to be ejected. The release mechanism has a fixed barrier member which holds the retractable pin in engagement with the locking lug until release by upward movement of the launch cradle beyond the barrier height.

Smyly, H. M.; Miller, C. D.; Cloyd, R. A.; Heller, C. (inventor)

1985-01-01

149

Gravity Probe B Experiment in 7D Space-and-Time Continuum  

E-print Network

This study deals with application of field equations in seven-dimensional space-and-time continuum to calculate geodetic and orbital gyroscope precession. It was demonstrated that unlike the classic theory the assumptions made completely correspond to the Gravity Probe B findings.

Yu. A. Portnov

2012-04-24

150

APPLICATION OF HIGH STABILITY OSCILLATORS TO RADIO SCIENCE EXPERIMENTS USING DEEP SPACE PROBES  

Microsoft Academic Search

The microwave telecommunication linkr between the earth and deep space probes have long been used to conduct rudio science experiments which take advantage 01 the phme coherency and stability of these links. These experiments measure changes in the pke delay of the signab to infer ekctrical, magnetic and gravitationalproperties of the sohr system environment and beyond through which the spacecraft

E. R. Kursinski

151

Time and space resolved Langmuir probe measurements of a pulsed vacuum arc plasma  

Microsoft Academic Search

The time and space evolution of pulsed vacuum arc plasma parameters have been measured using a single cylindrical Langmuir probe in a free expansion cup. Electron density ne, effective electron temperature Teff and electron energy distribution function (EEDF) are derived from the I–V curves using Druyvesteyn method. Results show that during the discharge time, the electron density ne is between

Lei Chen; Dazhi Jin; Xiaohua Tan; Jingyi Dai; Liang Cheng; Side Hu

152

Launch summary for 1978 - 1982. [sounding rockets, space probes, and satellites  

NASA Technical Reports Server (NTRS)

Data pertinent to the launching of space probes, soundings rockets, and satellites presented in tables include launch date, time, and site; agency rocket identification; sponsoring country or countries; instruments carried for experiments; the peak altitude achieved by the rockets; and the apoapsis and periapsis for satellites. The experimenter or institution involved in the launching is also cited.

Hills, H. K.

1984-01-01

153

83Gravity Probe-B : Testing Einstein Again! Space Math http://spacemath.gsfc.nasa.gov  

E-print Network

predictions of Albert Einstein's relativistic theory of gravity called General Relativity. The pointing83Gravity Probe-B : Testing Einstein Again! Space Math http://spacemath.gsfc.nasa.gov Copyright's theory of gravity were correct, the pointing direction should stay absolutely the same. If Einstein

154

Voyager II Encounter with Neptune: Voyager/Neptune Briefing  

NASA Technical Reports Server (NTRS)

The main focus of this lecture is to discuss the relative size of the planets, the formation of the solar system, details of atmospheric motion (atmospheric dynamics), the aspects of the magnetic fields, different ring systems, and the Triton satellite. The study evolves around the planets of Jupiter, Saturn, Uranus, and Neptune. Their temperature and absorption properties of the ice are discussed. Two of the chemicals being absorbed by the ice are ammonia and methane. Also discussed are the belt and zonal circulation models, jet streams, plumes and clouds, magnetic fields, planetary rings, the pressure on Triton, the atmosphere of Titan, Callisto, Aria, Ganymede, Ariel, Miranda, Io, Europa, Amalthea, Rhea, Dione, Tethys, Enceladus, Mimas, Hyperion, Oberon, Titania, and Umbriel. The lecture also contained some computerized simulation and various images from Voyager.

1989-01-01

155

46 CFR 46.05-20 - Great Lakes voyage.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 2013-10-01 false Great Lakes voyage. 46.05-20 Section 46.05-20 ...Definitions Used in This Part § 46.05-20 Great Lakes voyage. A Great Lakes voyage is any voyage from a United States port...

2013-10-01

156

46 CFR 46.05-20 - Great Lakes voyage.  

Code of Federal Regulations, 2012 CFR

... 2012-10-01 2012-10-01 false Great Lakes voyage. 46.05-20 Section 46.05-20 ...Definitions Used in This Part § 46.05-20 Great Lakes voyage. A Great Lakes voyage is any voyage from a United States port...

2012-10-01

157

46 CFR 46.05-20 - Great Lakes voyage.  

Code of Federal Regulations, 2010 CFR

... 2010-10-01 2010-10-01 false Great Lakes voyage. 46.05-20 Section 46.05-20 ...Definitions Used in This Part § 46.05-20 Great Lakes voyage. A Great Lakes voyage is any voyage from a United States port...

2010-10-01

158

46 CFR 46.05-20 - Great Lakes voyage.  

Code of Federal Regulations, 2011 CFR

... 2011-10-01 2011-10-01 false Great Lakes voyage. 46.05-20 Section 46.05-20 ...Definitions Used in This Part § 46.05-20 Great Lakes voyage. A Great Lakes voyage is any voyage from a United States port...

2011-10-01

159

The Galilean satellites and Jupiter - Voyager 2 imaging science results  

Microsoft Academic Search

Continuous global observations of Jupiter were made by Voyager 2 for a period of 63 days. Voyager 2 provided images that both complement and supplement the Voyager 1 images. The combined Voyager 1 and 2 observations of Jupiter provide an almost continuous record, over a 6-month period, of the behavior of the Jovian atmosphere at a resolution far better than

B. A. Smith; L. A. Soderblom; R. Beebe; J. Boyce; G. Briggs; M. Carr; S. A. Collins; T. V. Johnson; A. F. Cook II; G. E. Danielson; D. Morrison; A. INGERSOLL; H. MASURSKY; J. MCCAULEY; T. OWEN; C. SAGAN; E. M. SHOEMAKER; R. STROM; V. E. SUOMI; J. VEVERKA

1979-01-01

160

Planetary radio astronomy observations from Voyager 2 near Jupiter  

Microsoft Academic Search

The Voyager 2 Planetary Radio Astronomy experiment to Jupiter has confirmed and extended to higher zenomagnetic latitudes results from the identical experiment carried by Voyager 1. The kilometric emissions discovered by Voyager 1 often extended to 1 megahertz or higher on Voyager 2 and often consisted of negatively, or less frequently, positively drifting narrowband bursts. On the basis of tentative

J. W. Warwick; J. B. Pearce; A. C. Riddle; J. K. Alexander; M. D. Desch; M. L. Kaiser; J. R. Thieman; T. D. Carr; S. Gulkis; A. Boischot; Y. LEBLANC; B. M. PEDERSEN; D. H. STAELIN

1979-01-01

161

Voyager 2 Jupiter Eruption Movie  

NASA Technical Reports Server (NTRS)

This movie records an eruptive event in the southern hemisphere of Jupiter over a period of 8 Jupiter days. Prior to the event, an undistinguished oval cloud mass cruised through the turbulent atmosphere. The eruption occurs over avery short time at the very center of the cloud. The white eruptive material is swirled about by the internal wind patterns of the cloud. As a result of the eruption, the cloud then becomes a type of feature seen elsewhere on Jupiter known as 'spaghetti bowls'.

As Voyager 2 approached Jupiter in 1979, it took images of the planet at regular intervals. This sequence is made from 8 images taken once every Jupiter rotation period (about 10 hours). These images were acquired in the Violet filter around May 6, 1979. The spacecraft was about 50 million kilometers from Jupiter at that time.

This time-lapse movie was produced at JPL by the Image Processing Laboratory in 1979.

2000-01-01

162

Voyager 1 Red Spot Movie  

NASA Technical Reports Server (NTRS)

This movie shows the portion of Jupiter around the Great Red Spot as it swirls through more than 60 Jupiter days. Notice the difference in speed and direction of the various zones of the atmosphere. The interaction of the atmospheric clouds and storm shows how dynamic the Jovian atmosphere is.

As Voyager 1 approached Jupiter in 1979, it took images of the planet at regular intervals. This sequence is made from 66 images taken once every Jupiter rotation period (about 10 hours). This time-lapse movie uses images taken every time Jupiter longitude 68W passed under the spacecraft. These images were acquired in the Blue filter from Jan. 6 to Feb. 3 1979. The spacecraft flew from 58 million kilometers to 31 million kilometers from Jupiter during that time.

This time-lapse movie was produced at JPL by the Image Processing Laboratory in 1979.

2000-01-01

163

The Argonne Voyager multimedia server  

SciTech Connect

With the growing presence of multimedia-enabled systems, one will see an integration of collaborative computing concepts into the everyday environments of future scientific and technical workplaces. Desktop teleconferencing is in common use today, while more complex desktop teleconferencing technology that relies on the availability of multipoint (greater than two nodes) enabled tools is now starting to become available on PCs. A critical problem when using these collaboration tools is the inability to easily archive multistream, multipoint meetings and make the content available to others. Ideally one would like the ability to capture, record, playback, index, annotate and distribute multimedia stream data as easily as one currently handles text or still image data. While the ultimate goal is still some years away, the Argonne Voyager project is aimed at exploring and developing media server technology needed to provide a flexible virtual multipoint recording/playback capability. In this article the authors describe the motivating requirements, architecture implementation, operation, performance, and related work.

Disz, T.; Judson, I.; Olson, R.; Stevens, R. [Argonne National Lab., IL (United States). Mathematics and Computer Science Div.

1997-07-01

164

Probing interactions through space using spin-spin coupling.  

PubMed

The series of eight 5-(TeY)-6-(SePh)acenaphthenes (Y = Fp (2), Tol (3), An-p (4), An-o (5), Tp (6), Mes (7), Tip (8), Nap (9)) were prepared and structurally characterised by X-ray crystallography, solution and solid-state NMR spectroscopy and density functional theory (DFT/B3LYP) calculations. All members of the series, except 5, adopt a BA type configuration comparable to the parent compound 1 (Y = Ph), aligning the Te-C(Y) bond along the mean acenaphthene plane and promoting a nonbonded Se···Te-C(Y) 3c-4e type interaction to form to stabilise the molecule (G-dependence). 5 (Y = An-o) adopts a BC type conformation in the solid but DFT calculations show this optimises to BA. Indication of strong through-space peri-interactions between Te and Se are observed in the (77)Se and (125)Te NMR spectra, with J(Te,Se) spin-spin coupling constants (SSCCs) in the range -688 to -748 Hz. Evidence supporting the presence of this interaction was also found in solid-state NMR spectra of some of the compounds which exhibit an indirect spin-spin coupling on the same order of magnitude as observed in solution. In order to quantify the steric bulk of the aryl groups (Y), we introduce the crystallographic steric parameter (?), the cone angle measured from the furthest H atoms lying on the edges of the cone to the Te atom located at its vertex. Modification to Y has no apparent influence over the conformation of the molecule, the degree of molecular distortion occurring in the acenaphthene backbone or the extent of 3c-4e interaction; peri-distances for all eight compounds are within 0.08 Å and no apparent correlation is observed between the steric bulk of Y (?) and the (77)Se chemical shifts or J(Te,Se) SSCCs. In contrast, a good correlation is found between ? and (125)Te chemical shifts. DFT calculations performed on all members of the series confirm the comparable covalent bonding between Te and Se in the series, with WBIs of ca. 0.1 obtained. Natural bond orbital analysis shows a noticeable donor-acceptor interaction between a p-type lone pair on Se and a ?*(Te-C) antibonding orbital, confirming the onset of 3c-4e type bonding. PMID:24623141

Stanford, Martin W; Knight, Fergus R; Athukorala Arachchige, Kasun S; Sanz Camacho, Paula; Ashbrook, Sharon E; Bühl, Michael; Slawin, Alexandra M Z; Woollins, J Derek

2014-05-01

165

46 CFR Sec. 4 - Voyage terminations.  

Code of Federal Regulations, 2011 CFR

46 Shipping 8 2011-10-01 2011-10-01... Sec. 4 Section 4 Shipping MARITIME ADMINISTRATION...TRANSPORTATION A-NATIONAL SHIPPING AUTHORITY VOYAGE DATA...Final discharge of cargo or ballast. (2) Paying off of...

2011-10-01

166

46 CFR Sec. 4 - Voyage terminations.  

Code of Federal Regulations, 2010 CFR

46 Shipping 8 2010-10-01 2010-10-01... Sec. 4 Section 4 Shipping MARITIME ADMINISTRATION...TRANSPORTATION A-NATIONAL SHIPPING AUTHORITY VOYAGE DATA...Final discharge of cargo or ballast. (2) Paying off of...

2010-10-01

167

46 CFR Sec. 4 - Voyage terminations.  

46 Shipping 8 2014-10-01 2014-10-01... Sec. 4 Section 4 Shipping MARITIME ADMINISTRATION...TRANSPORTATION A-NATIONAL SHIPPING AUTHORITY VOYAGE DATA...Final discharge of cargo or ballast. (2) Paying off of...

2014-10-01

168

46 CFR Sec. 4 - Voyage terminations.  

Code of Federal Regulations, 2013 CFR

46 Shipping 8 2013-10-01 2013-10-01... Sec. 4 Section 4 Shipping MARITIME ADMINISTRATION...TRANSPORTATION A-NATIONAL SHIPPING AUTHORITY VOYAGE DATA...Final discharge of cargo or ballast. (2) Paying off of...

2013-10-01

169

46 CFR Sec. 4 - Voyage terminations.  

Code of Federal Regulations, 2012 CFR

46 Shipping 8 2012-10-01 2012-10-01... Sec. 4 Section 4 Shipping MARITIME ADMINISTRATION...TRANSPORTATION A-NATIONAL SHIPPING AUTHORITY VOYAGE DATA...Final discharge of cargo or ballast. (2) Paying off of...

2012-10-01

170

Voyager: Perils of advanced planning, 1960 - 1967  

NASA Technical Reports Server (NTRS)

Contract proposals; phased project planning; budgetary problems; Saturn 1 B-Centaur versus Saturn V; mission guidelines and management assignments; and the origins of the Voyager project are discussed.

1984-01-01

171

A 3D Radiative Transfer Simulation of Lyma-alpha Backscatter Intensity Reduced From Voyager’s Ultraviolet Spectrometer  

NASA Astrophysics Data System (ADS)

Models of the heliosphere have evolved for the past few decades to fit observations made by a large number of spacecraft. Voyager missions have provided unique in-situ measurements that have proven to be essential for model testing. Lyman-alpha backscatter intensity has been reduced from measurements taken by the ultraviolet spectrometers on board both Voyager spacecraft. We have developed a 3D Monte Carlo radiative transfer code to simulate this backscatter intensity by generating millions of photons from the sun to scatter within a neutral hydrogen distribution resulting from a state-of-the-art 3D MHD-kinetic neutral heliospheric model, both of which have been developed within the Center for Space Physics and Aeronomic Research at the University of Alabama in Huntsville. While many have attempted to simulate the Voyager observations, we are the first to achieve agreement with our results. In this presentation, we will discuss the core mechanisms driving the radiative transfer code, the statistical quantities collected, and the interpretation of the results relative to the spacecraft data.

Fayock, Brian; Zank, Gary; Heerikhuisen, Jacob

2014-06-01

172

On the detection of a cometary mass distribution. [by perturbations on space probe orbits  

NASA Technical Reports Server (NTRS)

The problem of detecting a possible cometary distribution on the fringes of the solar system is examined. The acceleration of a space probe due to a hypothetical cometary mass distribution with the surface density rising to a maximum and subsequently falling off with increasing distance from the sun is analyzed. The total minimum detectable cometary mass for the Pioneer and Mariner spacecraft is estimated on the basis of this model to be on the order of 1000 earth masses. Precision tracking of deep space probes is less sensitive by three orders of magnitude for the detection of an unseen cometary mass distribution at the fringes of the solar system than are the secular perturbations of long-period comets.

Boss, A. P.; Peale, S. J.

1976-01-01

173

Physical limitations in sensors for a drag-free deep space probe  

NASA Technical Reports Server (NTRS)

The inner perturbing forces acting on sensors were analyzed, taking into account the technological limitations imposed on the proof mass position pickup and proof mass acquisition system. The resulting perturbing accelerations are evaluated as a function of the drag-free sensor parameters. Perturbations included gravitational attraction, electrical action, magnetic action, pressure effects, radiation effects, and action of the position pickup. These data can be used to study the laws of guidance, providing an optimization of the space probe as a whole.

Juillerat, R.

1971-01-01

174

Time and Space-Resolved Optical Probing of Femtosecond-Laser-Driven Shock Waves in Aluminum  

Microsoft Academic Search

We present the first measurements of particle velocity histories at the interface between an aluminum sample shocked by a 120 fs laser-driven pressure pulse and a fused silica window. Frequency-domain interferometry is used to provide space- and time-resolved measurements of the phase shift of a pair of probe pulses backscattered at the shocked interface. Pressures of 1-3 Mbar are inferred

R. Evans; A. D. Badger; F. Falliès; M. Mahdieh; T. A. Hall; P. Audebert; J.-P. Geindre; J.-C. Gauthier; A. Mysyrowicz; G. Grillon; A. Antonetti

1996-01-01

175

The Deep Space Network. An instrument for radio navigation of deep space probes  

NASA Technical Reports Server (NTRS)

The Deep Space Network (DSN) network configurations used to generate the navigation observables and the basic process of deep space spacecraft navigation, from data generation through flight path determination and correction are described. Special emphasis is placed on the DSN Systems which generate the navigation data: the DSN Tracking and VLBI Systems. In addition, auxiliary navigational support functions are described.

Renzetti, N. A.; Jordan, J. F.; Berman, A. L.; Wackley, J. A.; Yunck, T. P.

1982-01-01

176

Telecommunications and data acquisition systems support for Voyager missions to Jupiter and Saturn, 1972-1981, prelaunch through Saturn encounter  

NASA Technical Reports Server (NTRS)

The Deep Space Network has supported the Voyager Project for approximately nine years, during which time implementation, testing, and operational support was provided. Four years of this time involved testing prior to launch; the final five years included network operations support and additional network implementation. Intensive and critical support intervals included launch and four planetary encounters. The telecommunications and data acquisition support for the Voyager Missions to Jupiter and Saturn are summarized.

Traxler, M. R.; Beauchamp, D. F.

1983-01-01

177

Voyages Through Time: Everything Evolves  

NASA Astrophysics Data System (ADS)

The SETI Institute, the California Academy of Sciences, and NASA Ames Research Center are developing standards-based curriculum materials for a one-year high school science course centered on the unifying theme of evolution. Scientists, teachers, curriculum writers, and media specialists are currently developing six modules that integrate astronomical, geological, and biological sciences as well as the history of science and technology. The sequence of lessons in each module will be designed to promote students' understanding and skills as defined by the National Science Education Standards and Benchmarks for Science Literacy. The modules cover: Cosmic Evolution, Planetary Evolution, Origin of Life, Diversification of Life, Hominid Evolution, and the Evolution of Technology. The core lessons for all six modules will be provided via CD-ROM, including instructional guidelines, science background information, and additional resources (print, audiovisual, software, WWW sites, databases, and telecommunications projects). These products will be published as a complete set for use as a year-long science course and will also be available as individual modules for use in discipline-based courses. Evolutionary change is a powerful framework for studying our world and our place therein. It is a story of epic size, capable of inspiring awe and of expanding our sense of time and place. This story is the basis of Voyages Through Time.

Tarter, Jill; Pendleton, Y.; DeVore, E.; O'Sullivan, K.; Taylor, S.

178

Voyages Through Time: Everything Evolves  

NASA Astrophysics Data System (ADS)

The SETI Institute, the California Academy of Sciences, NASA Ames Research Center, and San Francisco State University have developed standards-based curriculum materials for a one-year high school integrated science course centered on the unifying theme of evolution. Scientists, teachers, curriculum writers, and media specialists are currently finalizing six modules that integrate astronomical, geological, and biological sciences as well as the history of science and technology. The sequence of lessons in each module is designed to promote students' understanding and skills as defined by the National Science Education Standards and Benchmarks for Science Literacy. The modules cover: Cosmic Evolution, Planetary Evolution, Origin of Life, Evolution of Life, Hominid Evolution, and the Evolution of Technology. The core lessons for all six modules are provided via CD-ROM, including instructional guidelines, science background information, and additional resources (print, audiovisual, software, WWW sites, and databases). These products will be published as a complete set for use as a yearlong science course and will also be available as individual modules for use in discipline-based courses. Evolutionary change is a powerful framework for studying our world and our place therein. It is a story of epic size, capable of inspiring awe and of expanding our sense of time and place. This story is the basis of Voyages Through Time.

Fisher, Jane; Tarter, Jill; Devore, Edna; Pendleton, Yvonne; O'Sullivan, Kathleen; Burke, Meg

2004-06-01

179

Ancient Voyaging and Polynesian Origins  

PubMed Central

The “Polynesian motif” defines a lineage of human mtDNA that is restricted to Austronesian-speaking populations and is almost fixed in Polynesians. It is widely thought to support a rapid dispersal of maternal lineages from Taiwan ?4000 years ago (4 ka), but the chronological resolution of existing control-region data is poor, and an East Indonesian origin has also been proposed. By analyzing 157 complete mtDNA genomes, we show that the motif itself most likely originated >6 ka in the vicinity of the Bismarck Archipelago, and its immediate ancestor is >8 ka old and virtually restricted to Near Oceania. This indicates that Polynesian maternal lineages from Island Southeast Asia gained a foothold in Near Oceania much earlier than dispersal from either Taiwan or Indonesia 3–4 ka would predict. However, we find evidence in minor lineages for more recent two-way maternal gene flow between Island Southeast Asia and Near Oceania, likely reflecting movements along a “voyaging corridor” between them, as previously proposed on archaeological grounds. Small-scale mid-Holocene movements from Island Southeast Asia likely transmitted Austronesian languages to the long-established Southeast Asian colonies in the Bismarcks carrying the Polynesian motif, perhaps also providing the impetus for the expansion into Polynesia. PMID:21295281

Soares, Pedro; Rito, Teresa; Trejaut, Jean; Mormina, Maru; Hill, Catherine; Tinkler-Hundal, Emma; Braid, Michelle; Clarke, Douglas J.; Loo, Jun-Hun; Thomson, Noel; Denham, Tim; Donohue, Mark; Macaulay, Vincent; Lin, Marie; Oppenheimer, Stephen; Richards, Martin B.

2011-01-01

180

Interagency telemetry arraying for Voyager-Neptune encounter  

NASA Technical Reports Server (NTRS)

The reception capability of the Deep Space Network (DSN) has been improved over the years by increasing both the size and number of antennas at each complex to meet spacecraft-support requirements. However, even more aperture was required for the final planetary encounters of the Voyager 2 spacecraft. This need was met by arraying one radio astronomy observatory with the DSN complex in the United States and another with the complex in Australia. Following a review of augmentation for the Uranus encounter, both the preparation at the National Radio Astronomy (NRAO) Very Large Array (VLA) and the Neptune encounter results for the Parkes-Canberra and VLA-Goldstone arrays are presented.

Brown, D. W.; Brundage, W. D.; Ulvestad, J. S.; Kent, S. S.; Bartos, K. P.

1990-01-01

181

J. Phys. Chem. 1989, 93, 8149-8162 8149 Ultrafast Pump-Probe Spectroscopy: Femtosecond Dynamics in Liouville Space  

E-print Network

J. Phys. Chem. 1989, 93, 8149-8162 8149 Ultrafast Pump-Probe Spectroscopy: Femtosecond Dynamics in Liouville Space Yi Jing Yan, Laurence E. Fried,?and Shad Mukamel*9f Chemistry Department, University of Rochester, Rochester, New York 14627 (Received:May 23, 1989) A theory for ultrafast pump-probe

Mukamel, Shaul

182

Comparison of Galileo Probe and Earth-Based Translation Rates of Jupiter's Equatorial Clouds  

PubMed

The Doppler wind speeds derived from Galileo probe data are comparable with the maximum translation speeds observed in the equatorial zone by Voyager 1 and the Hubble Space Telescope. Slower published values of east-west winds are based on measurements of larger features and should be interpreted as translation rates of large weather systems interacting with the wind. The nature of the hot-spot region that the Galileo probe entered is compatible with a high-speed jet at 6 degrees north. The hot spot is associated with an equatorial weather system that spans 5 degrees of latitude and translates at 103 meters per second. PMID:8662572

Beebe; Simon; Huber

1996-05-10

183

Observations of the Jovian UV aurora by Voyager  

NASA Technical Reports Server (NTRS)

The observations of the Jovian aurora made by the Voyager UV spectrometer (UVS) during 1979 are analyzed, with special consideration given to the model fitting process. Several different estimates of the function specifying auroral arc geometry were tried, with the Broadfoot et al. (1981) estimate, found by probing with the tip of the UVS slit, giving the best agreement; this agreement is slightly better than the agreement with the Io torus footprint computed by Roederer et al. (1977). The results suggest that the UVS observations are more sensitive to the surface field geometry than are the Voyager flyby in situ observations. The results of a study of intensity maximum positions indicate that the particles exciting the spatially variable portion of the aurora are drifting west, implying either that these particles are electrons or that they are positive ions drifting east more slowly than the corotation lag of the Io torus region carries them to the west. The latter case is most consistent with the high-energy charged particle measurements.

Herbert, Floyd; Sandel, B. R.; Broadfoot, A. L.

1987-01-01

184

Voyager planetary radio astronomy studies  

NASA Technical Reports Server (NTRS)

Analysis of nonthermal radio emission data obtained by the Planetary Radio Astronomy (PRA) spectrometers on the Voyager 1 and 2 spacecraft was performed. This PRA data provided unique insights into the radio emission characteristics of the outer planets because of PRA's unique spectral response below the terrestrial ionospheric plasma frequency and its unprecedented proximity to the source. Of those results which were documented or published, this final report surveys only the highlights and cites references for more complete discussions. Unpublished results for Uranus, Neptune, and theoretical Ionian current distributions are presented at greater length. The most important conclusion to be drawn from these observations is that banded spectral emission is common to the radio emission below 1-2 MHz observed from all four Jovian planets. In every case multiple spectral features evolve on time scales of seconds to minutes. To the extent these features drift in frequency, they appear never to cross one another. The Neptunian spectral features appear to drift little or not at all, their evolution consisting principally of waxing and waning. Since other evidence strongly suggests that most or all of this radio emission is occurring near the local magnetospheric electron cyclotron frequency, this implies that this emission preferentially occurs at certain continually changing planetary radii. It remains unknown why certain radii might be favored, unless radial electric field components or other means serve to differentiate radially the magnetospheric plasma density, particle energy vectors, or particle coherence. Calculation of the spatial distribution and intensity of the Io-generated magnetospheric currents are also presented; these currents may be limited principally by wave impedance and local field strengths.

Staelin, David H.; Eikenberry, Stephen S.

1993-01-01

185

The deep space network. [tracking and communication support for space probes  

NASA Technical Reports Server (NTRS)

The objectives, functions, and organization of the deep space network are summarized. Progress in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations is reported. Interface support for the Mariner Venus Mercury 1973 flight and Pioneer 10 and 11 missions is included.

1974-01-01

186

Voyager 2 Observes Energetic Electrons - Duration: 0:15.  

NASA Video Gallery

This animation shows the Voyager 2 observations of energetic electrons. Voyager 2 detected a dramatic drop of the flux of electrons as it left the sector region. The intense flux came back as soon ...

187

Voyager - Humanity's Farthest Journey - Duration: 3:11.  

NASA Video Gallery

After 33 years, NASA's twin Voyager spacecraft are still going strong and still sending home information. This video features highlights of the Voyager journeys to the outer planets, and looks at t...

188

Research of flexible beam impact dynamics based on space probe-cone docking mechanism  

NASA Astrophysics Data System (ADS)

The issue considered in this paper is the dynamic behavior of flexible probe based on space probe-cone docking mechanism in the docking process. The theoretical model of docking impact dynamics based on flexible beam is built according to the Lagrange Analytical Mechanics theory. The contact problem is solved by using Hertz point-surface contact model. Assumed Modes Method is introduced to describe the deformation of flexible beam. Runge-Kutta numerical method is used to solve this theoretical model. Results of the theoretical model show a good agreement with the experimental and MSC.Patran/Dytran simulation results. Moreover, the influence of flexible beam parameter on docking impact process is analyzed based on the theoretical model.

Zhang, Xiang; Huang, Yiyong; Han, Wei; Chen, Xiaoqian

2012-03-01

189

Combined Lick-Voyager Reference Star Catalogue (Dunham 1986)  

Microsoft Academic Search

The catalogue contains accurate equatorial coordinates for stars in several bands of sky against which cameras of Voyager spacecraft were pointed for observations in the regions of Jupiter, Saturn, Uranus and Neptune during the flyby. This catalogue is compiled by combining the four reference star catalogues for Voyager mission: Uranus-Voyager Reference Star Catalogue Klemola A.R., Owen Jr. W.M. Neptune-Voyager Reference

D. W. Dunham

1995-01-01

190

Voyager 1 encounter with the Saturnian system  

NASA Technical Reports Server (NTRS)

The Voyager 1 Saturn flyby mission of March 1979 is reviewed, with brief discussions of its flight, trajectory, science plan formulation and telemetered data. Analytical results of such data with respect to Saturn's atmosphere, rings, icy satellites, Titan satellite atmosphere and the Saturn magnetosphere, are summarized. The Voyager science investigations comprise imaging science (ISS), infrared radiation (IRIS), photopolarimetry (PPS), ultraviolet spectroscopy (UVS), radio science (RSS), magnetic fields (MAG), plasma particles (PLS), plasma waves (PWS), planetary radio astronomy (PRA), low energy charged particles (LECP), and cosmic-ray particles (CRS).

Stone, E. C.; Miner, E. D.

1981-01-01

191

Darwin: Voyage of Discovery (ScienceWorld)  

NSDL National Science Digital Library

This online article is from the Museum's Science Explorations, a collaboration between AMNH and Scholastic designed to promote science literacy. Written for students in grades 6-10, this article from Science World magazine has an interview with AMNH paleontologist Niles Eldredge, in which he explains how the eye-opening sights Charles Darwin encountered during his five-year voyage on the HMS Beagle inspired his thinking about the diversity of life on Earth. There are Web links that offer further opportunities for learning about Darwin and his years after the voyage.

192

Advanced Receiver tracking of Voyager 2 near solar conjunction  

NASA Technical Reports Server (NTRS)

The Advanced Receiver (ARX) was used to track the Voyager 2 spacecraft at low Sun-Earth-Probe (SEP) angles near solar conjunction in December of 1987. The received carrier signal exhibited strong fluctuations in both phase and amplitude. The ARX used spectral estimation and mathematical modeling of the phase and receiver noise processes to set an optimum carrier tracking bandwidth. This minimized the mean square phase error in tracking carrier phase and thus minimized the loss in the telemetry signal-to-noise ratio due to the carrier loop. Recovered symbol SNRs and errors in decoded engineering data for the ARX are compared with those for the current Block 3 telemetry stream. Optimum bandwidths are plotted against SEP angle. Measurements of the power spectral density of the solar phase and amplitude fluctuations are also given.

Brown, D. H.; Hurd, W. J.; Vilnrotter, V. A.; Wiggins, J. D.

1988-01-01

193

Geometry of Schroedinger Space-Times II: Particle and Field Probes of the Causal Structure  

E-print Network

We continue our study of the global properties of the z=2 Schroedinger space-time. In particular, we provide a codimension 2 isometric embedding which naturally gives rise to the previously introduced global coordinates. Furthermore, we study the causal structure by probing the space-time with point particles as well as with scalar fields. We show that, even though there is no global time function in the technical sense (Schroedinger space-time being non-distinguishing), the time coordinate of the global Schroedinger coordinate system is, in a precise way, the closest one can get to having such a time function. In spite of this and the corresponding strongly Galilean and almost pathological causal structure of this space-time, it is nevertheless possible to define a Hilbert space of normalisable scalar modes with a well-defined time-evolution. We also discuss how the Galilean causal structure is reflected and encoded in the scalar Wightman functions and the bulk-to-bulk propagator.

Matthias Blau; Jelle Hartong; Blaise Rollier

2010-05-05

194

Near Earth Asteroid Rendezvous - A Pictorial Voyage  

NSDL National Science Digital Library

This site offers students an opportunity to participate in a pictorial voyage that follows the NEAR spacecraft from its inception through the cruise phase to asteroid 433 Eros. They will learn about the rationale for visiting an asteroid, the instruments and construction of the spacecraft, and follow its flyby of the asteroid Mathilde, swingby of Earth, and encounter with Eros.

195

Voyager: Exploring through the Public Eye  

E-print Network

Voyager: Exploring through the Public Eye Giny Cheong George Mason University September 25 2012 n began ding jupspacecraft data atmosphere solar m giant orbit times plan ace ct exp s time bill closest scientist euver million gency anetary manager early f webster o udy navig orbits ntire eastern lo

196

Voyager 2 at Neptune - Imaging science results  

Microsoft Academic Search

Neptune's atmosphere is revealed by Voyager 2 images to contain clouds of methane ice above a lower deck of hydrogen sulfide or ammonia ices, and to be dominated by an anticyclonic storm system designated the 'Great Dark Spot'; this bears both similarities and differences to the Great Red Spot of Jupiter. Like the rings of Uranus, those of Neptune are

B. A. Smith; L. A. Soderblom; D. Banfield; C. Barnet; R. F. Beebe; A. T. Bazilevskii; K. Bollinger; J. M. Boyce; G. A. Briggs; A. Brahic; E. M. Shoemaker; G. E. Danielson; E. DeJong; C. Howell; A. P. Ingersoll; J. Schwartz; D. I. Kuehn; A. T. Basilevsky; R. H. Brown; Crisp Collins; J. Goguen; H. Hammel; C. J. Hansen; T. V. Johnson; W. Owen; D. Rudy; S. P. Synnott; R. J. Terrile; I. Grenier; B. Sicardy; C. Chyba; C. P. Helfenstein; C. Sagan; D. Simonelli; P. Thomas; W. R. Thompson; J. Veverka; A. Verbiscer; P. Rogers; M. Showalter; J. Spencer; L. A. Sromovsky; C. Stoker; R. G. Strom; V. E. Suomi; S. P. Synott

1989-01-01

197

Voyager Photometry of Saturn's A Ring  

Microsoft Academic Search

Saturn's A Ring samples a wide range of dynamical environments, from the relatively unperturbed, optically thick inner region to the outer part of the ring, which contains numerous density waves. We analyze Voyager images of the A Ring to determine how the reflectivity of different radial regions varies with lighting and viewing geometry. We model our data with a classical

Luke Dones; Jeffrey N. Cuzzi; Mark R. Showalter

1993-01-01

198

Ultraviolet spectrometer experiment for the Voyager mission  

Microsoft Academic Search

The Voyager Ultraviolet Spectrometer (UVS) is an objective grating spectrometer covering the wavelength range of 500–1700 Å with 10 Å resolution. Its primary goal is the determination of the composition and structure of the atmospheres of Jupiter, Saturn, Uranus and several of their satellites. The capability for two very different observational modes have been combined in a single instrument. Observations

A. L. Broadfoot; B. R. Sandel; D. E. Shemansky; S. K. Atreya; T. M. Donahue; H. W. Moos; J. L. Bertaux; J. E. Blamont; J. M. Ajello; D. F. Strobel; J. C. McConnell; A. Dalgarno; R. Goody; M. B. McElroy; Y. L. Yung

1977-01-01

199

The Hemispheric Roots of the Columbian Voyages.  

ERIC Educational Resources Information Center

Urges that the search for origins of European exploration extend to Africa and East Asia and their international trade. Cites contributions of India and the Arabs, Chinese, and Malaysians. Emphasizes the importance of mathematics, navigation, and sailing technology. Argues that without these contributions the European voyages would not have been…

Shaffer, Lynda N.

1991-01-01

200

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

NASA Astrophysics Data System (ADS)

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 scientists and engineers may alleviate some common stereotypes about these careers. When students engage with the scientists and engineers at APL, they see first-hand that successful science and engineering requires a diverse team with multi-disciplinary backgrounds. Activities throughout the day develop student understanding about science and technology, and address the fundamental concepts that fall under the National Science Education Content Standards. Students are immersed in a hands-on experience designed to facilitate understanding of the History and Nature of Science. Throughout the day students interact with people of diverse backgrounds and interests while hearing about the specific ways various individuals and teams of people contribute to the science and technology of the mission, addressing the concepts which fall under the headings of Science as a Human Endeavor, Nature of Science, and History of Science. Getting students outside the classroom to visit APL is an exclusive opportunity; evaluations have indicated that students became interested in learning more about space science and STEM careers after attending a Space Academy event.

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

2013-12-01

201

1978 Aeronautics and Space Highlights  

NASA Technical Reports Server (NTRS)

These highlights include the space shuttle, new astronauts, Pioneers to Venus, Voyagers to Jupiter and Saturn, High Energy Astronomy Observatories Space Telescope, Landsat/Seasat, space applications, wind energy research, and aeronautics.

1978-01-01

202

Getting together in deep space - The Rosetta space probe's long trek to Comet 67/P Churyumov-Gerasimenko  

NASA Astrophysics Data System (ADS)

The countdown to Rosetta’s rendezvous in space began on 1 March 1997. At the end of February 2004, seven years and not a few headaches later, the European Space Agency (ESA) probe will at last be setting off on its journey to meet Comet Churyumov-Gerasimenko. The long-planned get-together will not however take place until the middle of 2014. A few months after arriving at the comet, Rosetta will release a small lander onto its surface. Then, for almost two years it will investigate Churyumov-Gerasimenko from close up. Dr Gerhard Schwehm, lead scientist for the Rosetta project, explains that, “With this mission we will be breaking new ground - this will be the first protracted cometary encounter.” The trip to the meeting place in space will certainly be a long one, located as it is some 4.5 astronomical units from the Sun, which translates into something like 675 million kilometres. Rosetta will be on the road for ten years, during which time it will clock up in excess of five billion kilometres. Launch in February 2004 Rosetta will be waved off on 26 February when it lifts off from the space centre in Kourou, French Guiana, aboard an Ariane 5 launcher. Shortly after the spacecraft’s release, its solar panels will be deployed and turned towards the Sun to build up the necessary power reserves. Its various systems and experiments will be gradually brought into operation and tested. Just three months into the mission the first active phase will be over, followed by final testing of the experiments in October 2004. Rosetta will then spend the following years flying a lonely path to the comet, passing by the Earth, Mars, the Earth and the Earth again. There is no alternative to this detour, for even Ariane 5, the most powerful launcher on the market today, lacks the power to hurl the probe on a direct route to the comet. To get the required momentum, it will rely on swing-by manœuvres, using the gravitation pull of Mars (in 2007) and the Earth (three times, in 2005, 2007 and 2008) to pick up speed. Asteroids for company A change is as good as a rest, and a meeting with at least one asteroid should help break the monotony for Rosetta. The spacecraft will come close to an asteroid at the end of 2008. Asteroids are, it will be remembered, rocky bodies, some as large as mountains, some even larger, that orbit the Sun in much the same way as planets. “These ‘brief encounters’ are a scientific opportunity and also a chance to test Rosetta’s instrument payload,” says Gerhard Schwehm. But asteroid exploration also serves an entirely practical purpose: “The more we find out about them, the better the prospect of being able one day to avert a possible collision.” Following a period of low-activity cruising, the probe’s course will be adjusted one last time in May 2011. From July 2011, a further two-and-a-half years' radio silence will be observed, and Rosetta, left entirely to its own resources, will fly close to the Jupiter orbit. Link-up in 2014 Finally, in January 2014, the probe will be reactivated and will, by October 2014, be only a few kilometres distant from Churyumov-Gerasimenko. This is where the dream of so many scientists becomes reality. Having deposited its precious lander cargo on the comet’s surface, Rosetta will continue to orbit Churyumov-Gerasimenko and together they will spend the next seventeen months flying towards the Sun. Rosetta was built by an international consortium led by Astrium. The lander probe was developed in Cologne under the aegis of the DLR, Germany’s space agency, with contributions from ESA and research centres in Austria, Finland, France, Hungary, Ireland, Italy and Great Britain. The comet explorer carries ten scientific instruments. Their job is to draw out the secrets of the comet’s chemical and physical composition and reveal its magnetic and electrical properties. Using a specially designed camera, the lander will take pictures in the macro and micro ranges and send all the data thus acquired back to Earth, via Rosetta. “This will be our first ever chance to

2004-02-01

203

Antenna arraying of Voyager telemetry signals by symbol stream combining  

NASA Technical Reports Server (NTRS)

Telemetry signals received from the Voyager 2 spacecraft at Deep Space Stations at Parkes and Canberra, Australia, on February 6, 1986, were combined by the method of symbol stream combining. This second demonstration of symbol stream combining followed the International Cometary Explorer (ICE) demonstration at Giacobini-Zinner encounter in September 1985. The Voyager demonstration was at a symbol rate of 43.2 ksymb/s, compared to 2 ksymb/s for ICE. Recording, playback, and combining at this higher rate were demonstrated. The average symbol signal-to-noise ratio (SNR) of the combined data was 2.84 dB, or 0.23 dB less than the sum of the SNRs of the two imput symbol streams. This 0.23 loss from ideal combining was due to use of 4-bit quantization of the input symbol stream and imperfect scaling. A practical implementation with 8-bit quantization could achieve combining losses of under 0.05 dB over a wide dynamic range of input signal levels.

Hurd, W. J.; Rabkin, J.; Russell, M. D.; Siev, B.; Cooper, H. W.; Anderson, T. O.; Winter, P. U.

1986-01-01

204

Wall current probe: A non-invasive in situ plasma diagnostic for space and time resolved current density distribution measurement  

SciTech Connect

In the context of low temperature plasma research, we propose a wall current probe to determine the local charged particle fluxes flowing to the chamber walls. This non-intrusive planar probe consists of an array of electrode elements which can be individually biased and for which the current can be measured separately. We detail the probe properties and present the ability of the diagnostic to be used as a space and time resolved measurement of the ion and electron current density at the chamber walls. This diagnostic will be relevant to study the electron transport in magnetized low-pressure plasmas.

Baude, R.; Gaboriau, F.; Hagelaar, G. J. M. [Université de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d’énergie), 118 route de Narbonne, F-31062 Toulouse Cedex 9, France and CNRS, LAPLACE, F-31062, Toulouse (France)] [Université de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d’énergie), 118 route de Narbonne, F-31062 Toulouse Cedex 9, France and CNRS, LAPLACE, F-31062, Toulouse (France)

2013-08-15

205

Time-resolved HAXPES at SACLA: probe and pump pulse-induced space-charge effects  

NASA Astrophysics Data System (ADS)

Time-resolved hard x-ray photoelectron spectroscopy (trHAXPES) is established using the x-ray free-electron laser SACLA. The technique extends time-resolved photoemission into the hard x-ray regime and, as a core-level spectroscopy, combines element and atomic-site specificity and sensitivity to the chemical environment with femtosecond time resolution and bulk (sub-surface) sensitivity. The viability of trHAXPES using 8 keV x-ray free-electron-laser radiation is demonstrated by a systematic investigation of probe and pump pulse-induced vacuum space-charge effects on the V 1s emission of VO2 and the Ti 1s emission of SrTiO3. The time and excitation energy dependencies of the measured spectral shifts and broadenings are compared to the results of N-body numerical simulations and simple analytic (mean-field) models. Good agreement between the experimental and calculated results is obtained. In particular, the characteristic temporal evolution of the pump pulse-induced spectral shift is shown to provide an effective means to determine the temporal overlap of pump and probe pulses. trHAXPES opens a new avenue in the study of ultrafast atomic-site specific electron and chemical dynamics in materials and at buried interfaces.

Oloff, L.-P.; Oura, M.; Rossnagel, K.; Chainani, A.; Matsunami, M.; Eguchi, R.; Kiss, T.; Nakatani, Y.; Yamaguchi, T.; Miyawaki, J.; Taguchi, M.; Yamagami, K.; Togashi, T.; Katayama, T.; Ogawa, K.; Yabashi, M.; Ishikawa, T.

2014-12-01

206

Gravity Probe B: final results of a space experiment to test general relativity.  

PubMed

Gravity Probe B, launched 20 April 2004, is a space experiment testing two fundamental predictions of Einstein's theory of general relativity (GR), the geodetic and frame-dragging effects, by means of cryogenic gyroscopes in Earth orbit. Data collection started 28 August 2004 and ended 14 August 2005. Analysis of the data from all four gyroscopes results in a geodetic drift rate of -6601.8±18.3??mas/yr and a frame-dragging drift rate of -37.2±7.2??mas/yr, to be compared with the GR predictions of -6606.1??mas/yr and -39.2??mas/yr, respectively ("mas" is milliarcsecond; 1??mas=4.848×10(-9)??rad). PMID:21702590

Everitt, C W F; DeBra, D B; Parkinson, B W; Turneaure, J P; Conklin, J W; Heifetz, M I; Keiser, G M; Silbergleit, A S; Holmes, T; Kolodziejczak, J; Al-Meshari, M; Mester, J C; Muhlfelder, B; Solomonik, V G; Stahl, K; Worden, P W; Bencze, W; Buchman, S; Clarke, B; Al-Jadaan, A; Al-Jibreen, H; Li, J; Lipa, J A; Lockhart, J M; Al-Suwaidan, B; Taber, M; Wang, S

2011-06-01

207

Gravity Probe B: Final Results of a Space Experiment to Test General Relativity  

E-print Network

Gravity Probe B, launched 20 April 2004, is a space experiment testing two fundamental predictions of Einstein's theory of General Relativity (GR), the geodetic and frame-dragging effects, by means of cryogenic gyroscopes in Earth orbit. Data collection started 28 August 2004 and ended 14 August 2005. Analysis of the data from all four gyroscopes results in a geodetic drift rate of -6,601.8+/- 18.3 mas/yr and a frame-dragging drift rate of -37.2 +/- 7.2 mas/yr, to be compared with the GR predictions of -6,606.1 mas/yr and -39.2 mas/yr, respectively (`mas' is milliarc-second; 1mas = 4.848 x 10-9 rad).

C. W. F. Everitt; D. B. DeBra; B. W. Parkinson; J. P. Turneaure; J. W. Conklin; M. I. Heifetz; G. M. Keiser; A. S. Silbergleit; T. Holmes; J. Kolodziejczak; M. Al-Meshari; J. C. Mester; B. Muhlfelder; V. Solomonik; K. Stahl; P. Worden; W. Bencze; S. Buchman; B. Clarke; A. Al-Jadaan; H. Al-Jibreen; J. Li; J. A. Lipa; J. M. Lockhart; B. Al-Suwaidan; M. Taber; S. Wang

2011-05-17

208

Scalar Field Probes of Power-Law Space-Time Singularities  

E-print Network

We analyse the effective potential of the scalar wave equation near generic space-time singularities of power-law type (Szekeres-Iyer metrics) and show that the effective potential exhibits a universal and scale invariant leading x^{-2} inverse square behaviour in the ``tortoise coordinate'' x provided that the metrics satisfy the strict Dominant Energy Condition (DEC). This result parallels that obtained in hep-th/0403252 for probes consisting of families of massless particles (null geodesic deviation, a.k.a. the Penrose Limit). The detailed properties of the scalar wave operator depend sensitively on the numerical coefficient of the x^{-2}-term, and as one application we show that timelike singularities satisfying the DEC are quantum mechanically singular in the sense of the Horowitz-Marolf (essential self-adjointness) criterion. We also comment on some related issues like the near-singularity behaviour of the scalar fields permitted by the Friedrichs extension.

Matthias Blau; Denis Frank; Sebastian Weiss

2006-03-01

209

The Neptune System in Voyager's Afterglow.  

PubMed

Any time the view of a planet leaps from a fuzzy dot accompanied by two pinpoints of light to the riveting details of swirling clouds, rings, cratered moonlets, and even individual dust particles, planetary science is going to be in for some upheaval. Voyager 2's encounter with Neptune was no exception. Something as seemingly innocuous as an hour or two shift in the new length of a Neptunian day is giving meteorologists and physicists fits. And Neptune's canted, complex magnetic field found by Voyager knocks into a cocked hat most ideas about why a similar field at Uranus was unique. But there were more reassuring discoveries as well. Here are samplings of both sorts of findings. PMID:17776790

Kerr, R A

1989-09-29

210

Analysis of clumps in Saturn's F ring from Voyager and Cassini  

NASA Astrophysics Data System (ADS)

Saturn's F ring is subject to dynamic structural changes over short periods. Among the observed phenomena are diffuse extended bright clumps (ECs) ?3-40° in longitudinal extent. These ECs appear, evolve, and disappear over a span of days to months. ECs have been seen by the two Voyager spacecraft, the Cassini Orbiter, and various ground- and space-based telescopes. Showalter (Showalter, M.R. [2004]. Icarus 171, 356-371) analyzed all Voyager images of the F ring and found that there were 2-3 major and 20-40 minor ECs present in the ring at any given time. We expand upon these results by comparing the ECs seen by Voyager to those seen by Cassini in 2004-2010. We find that the number of minor ECs has stayed roughly constant and the ECs have similar distributions of angular width, absolute brightness, and semimajor axis. However, the common exceptionally bright ECs seen by Voyager are now exceedingly rare, with only two instances seen by Cassini in the 6 years, and they are now also much dimmer relative to the mean ring background. We hypothesize that these bright ECs are caused by the repeated impacts of small moonlets with the F ring core, and that these moonlets have decreased in number in the 25 years between missions.

French, Robert S.; Hicks, Shannon K.; Showalter, Mark R.; Antonsen, Adrienne K.; Packard, Douglas R.

2014-10-01

211

Spectrophotometry of Io - Preliminary Voyager 1 results  

Microsoft Academic Search

Multispectral images of Io acquired with the Voyager 1 narrow-angle camera agree with earth-based spectrophotometry to better than 10%. Although the surface materials have general spectral properties similar to various allotropes of sulfur, their ultraviolet (UV) reflectances are much higher. It is likely that varying amounts of SO2 frost mixed with or absorbed on sulfur-rich materials raises the UV reflectance.

L. Soderblom; T. Johnson; D. Morrison; E. Danielson; B. Smith; J. Veverka; A. Cook; C. Sagan; P. N. Kupferman; D. Pieri; J. A. Mosher; C. Avis; J. Gradie; T. Clancy

1980-01-01

212

Fourier spectroscopy on planetary missions including Voyager  

NASA Technical Reports Server (NTRS)

In the last dozen years spaceborne Fourier transform spectrometers have obtained infrared emission spectra of Earth, Mars, Jupiter, Saturn and Titan as well as of the Galilean and other Saturnian satellites and Saturn's rings. Intercomparisons of the properties of planetary atmospheres and of the characteristics of solid surfaces are now feasible. The principles of remotely sensing the environment on a planetary body are dicussed. Special consideration is given to the most recent results obtained by the Voyager infrared investigation on the Saturn system.

Hanel, R. A.

1981-01-01

213

Voyager 2 Movie of Saturn's Moon: Phoebe  

NASA Technical Reports Server (NTRS)

Voyager 2 took this photo sequence of Saturn's outer satellite, Phoebe, on Sept. 4, 1981, from 2.2 million kilometers (1.36 million miles) away. The top image is the normal version and the bottom is an enhanced version to increase resolution. This sequence lasts 23.4 hours and contains 35 images. The early images were taken about 43 minutes apart, while the later ones are about 29 minutes apart. There are two significant gaps in the sequence: images 7 and 8 are separated by 2.3 hours and images 19 and 20 are separated by 2.8 hours.

Because the sunlight is coming from the left, mountains and ridges can best be seen as they reflect the sunlight near the terminator (right side of Phoebe). Other intrinsically bright spots can be seen rotating across the whole disk. In this time-lapse sequence, Phoebe appears to be a lumpy spheroid with possible large mountains sometimes showing on the limb (left side of Phoebe). The photos show that Phoebe is about 220 kilometers (132 miles) in diameter. Its rotation period (length of day) was determined from this set of images to be 9.4 hours (see Thomas, P., et al, 'Phoebe: Voyager 2 Observations', Journal of Geophysical Research, vol. 88, p. 8736, 1 November 1983).

These images were processed by the Multimission Image Processing Laboratory of the Jet Propulsion Laboratory. The Voyager Project is managed for NASA by the Jet Propulsion Laboratory.

2000-01-01

214

Experimental and computational probes of the space in a self-assembled capsule  

PubMed Central

Self-assembled capsules are hosts that recognize and surround smaller molecule guests of appropriate size, shape, and chemical surfaces. The space available inside is a cage of fixed solvent molecules, many of which are aromatic. These aromatics provide anisotropic shielding to guests, and a map of induced magnetic shielding for the inner space can be obtained through nucleus-independent chemical shift calculations. Experimental values of the magnetic environment can be determined by NMR spectra of the guests inside. We describe here the environment in a cylindrical capsule with tapered ends. A series of terminal acetylenes—the narrowest of organic structures—was synthesized and used to probe the magnetic shielding of the capsule’s ends. Their NMR spectra showed that the acetylenic hydrogen experiences deshielding as it is forced deeper into the tapered end of the capsule where four benzene rings converge. Modeling and density functional theory calculations provided excellent agreement with the experimental values and established a molecular ruler to explore steric and magnetic environments inside the capsule. PMID:16751271

Ajami, Dariush; Iwasawa, Tetsuo; Rebek, Julius

2006-01-01

215

Application of high stability oscillators to radio science experiments using deep space probes  

NASA Technical Reports Server (NTRS)

The microwave telecommunication links between the earth and deep space probes have long been used to conduct radio science experiments which take advantage of the phase coherency and stability of these links. These experiments measure changes in the phase delay of the signals to infer electrical, magnetic and gravitational properties of the solar system environment and beyond through which the spacecraft and radio signals pass. The precision oscillators, from which the phase of the microwave signals are derived, play a key role in the stability of these links and therefore the sensitivity of these measurements. These experiments have become a driving force behind recent and future improvements in the Deep Space Network and spacecraft oscillators and frequency and time distribution systems. Three such experiments which are key to these improvements are briefly discussed and relationship between their sensitivity and the signal phase stability is described. The first is the remote sensing of planetary atmospheres by occultation in which the radio signal passes through the atmosphere and is refracted causing the signal pathlength to change from which the pressure and the temperature of the atmosphere can be derived. The second experiment is determination of the opacity of planetary rings by passage of the radio signals through the rings. The third experiment is the research for very low frequency gravitational radiation. The fractional frequency variation of the signal is comparable to the spatial strain amplitude the system is capable of detecting. A summary of past results and future possibilities for these experiments are presented.

Kursinski, Emil R.

1990-01-01

216

Magnetically insulated baffled probe for real-time monitoring of equilibrium and fluctuating values of space potentials, electron and ion temperatures, and densities  

SciTech Connect

By restricting the electron-collection area of a cold Langmuir probe compared to the ion-collection area, the probe floating potential can become equal to the space potential, and thus conveniently monitored, rather than to a value shifted from the space potential by an electron-temperature-dependent offset, i.e., the case with an equal-collection-area probe. This design goal is achieved by combining an ambient magnetic field in the plasma with baffles, or shields, on the probe, resulting in species-selective magnetic insulation of the probe collection area. This permits the elimination of electron current to the probe by further adjustment of magnetic insulation which results in an ion-temperature-dependent offset when the probe is electrically floating. Subtracting the floating potential of two magnetically insulated baffled probes, each with a different degree of magnetic insulation, enables the electron or ion temperature to be measured in real time.

Demidov, V. I.; Koepke, M. E. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States); Raitses, Y. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

2010-10-15

217

HUBBLE SPACE TELESCOPE NICMOS OBSERVATIONS OF T DWARFS: BROWN DWARF MULTIPLICITY AND NEW PROBES OF THE L/T TRANSITION  

E-print Network

HUBBLE SPACE TELESCOPE NICMOS OBSERVATIONS OF T DWARFS: BROWN DWARF MULTIPLICITY AND NEW PROBES-type field brown dwarfs. Five are resolved as binary systems with angular separations of 0B05Y0B35-unity mass ratios--are consistent with previous results for field brown dwarf binaries. Three of the binaries

Burgasser, Adam J.

218

Voyager 1 UVS measurements of Galactic cosmic rays  

NASA Astrophysics Data System (ADS)

Detectors of the Ultra-Violet Spectrographs (UVS) on board the Voyagers provide independent measurements of galactic cosmic ray (GCR) fluxes. The energy and angular response are derived from correlative studies with other Voyager Instruments. We show the evolution of the GCR flux and anisotropy during and after the abrupt increases in 2012. Using data from UVS and other instruments we show strong evidence for the end of the GCR heliospheric modulation in the 300 MeV range at the present location of Voyager 1, in line with the flux steadiness since September 2012. This suggests that Voyager already entered the interstellar medium, and we discuss potential reasons.

Lallement, R.; Quemerais, E.; Bertaux, J.; Sandel, B. R.

2013-12-01

219

Xenprobus, a Lightweight User-Space Probing Framework for Xen Virtual Machine  

Microsoft Academic Search

This paper presents Xenprobes, a lightweight framework to probe the guest kernels of Xen Virtual Machine. Xen- probes is useful for various purposes such as as moni- toring real-time status of production systems, analyzing performance bottlenecks, logging specific events or trac- ing problems of Xen-based guest kernel. Compared to other kernel probe solutions, Xenprobes introduces some unique advantages. To name

Anh-quynh Nguyen; Kuniyasu Suzaki

2007-01-01

220

Organic Molecules in the Interstellar Medium, Comets, and Meteorites: A Voyage from Dark Clouds to the Early Earth  

Microsoft Academic Search

Our understanding of the evolution of organic molecules, and their voyage from molecular clouds to the early solar system and Earth, has changed dramatically. Incorporating recent observational results from the ground and space, as well as laboratory simulation experiments and new methods for theoretical modeling, this review recapitulates the inventory and distribution of organic molecules in different environments. The evolution,

Pascale Ehrenfreund; Steven B. Charnley

2000-01-01

221

Voyager UVS observations of the Hydrogen Wall  

NASA Astrophysics Data System (ADS)

We compare new results of models of the interplanetary H Lyman alpha intensity background in the outer heliosphere with scans performed by the Voyager 1/2 UVS instruments between 1993 and 2003. This study shows that the excess intensity initially reported by Quemerais et al. (1995) can be explained by models of the hydrogen atoms distribution including effects of the heliospheric interface. The models of the hydrogen atom distribution in the interplanetary medium used in this work have been developed following the numerical scheme presented by Baranov and Malama (1993). Recent improvements are described by Izmodenov et al. (2005). Radiative transfer computations of the interplanetary Lyman alpha intensity are made following a Monte-Carlo approach presented by Quemerais (2000) and Quemerais and Izmodenov (2002). We find that the upwind intensity excess observed in the outer heliosphere and initially reported by Quemerais et al. (1995) can be explained by a full radiative transfer computation. This computation must include a full description of the velocity distributions of the different hydrogen populations that enter the heliosphere after crossing the interface. The excess upwind intensity observed by UVS on Voyager 1 and Voyager 2 can be explained as an emission of the decelerated hydrogen atoms near the stagnation point of the heliopause. Because those atoms are slowed down relative to the main hydrogen flow, photons scattered by them suffer less absorption and are visible at a much larger distance than it is the case for photons scattered by atoms in the main flow. The shape and extent of the excess emission gives information about the decelerated population near the heliopause stagnation point. A detailed comparison between the data and our present model does not show a complete agreement. The modeled intensity excess is larger than the observed one. We will discuss possible improvements to the H distribution model.

Quemerais, E.; Sandel, B. R.; Lallement, R.

2009-12-01

222

Darwin: Voyage of Discovery (SuperScience)  

NSDL National Science Digital Library

This online article is from the Museum's Science Explorations, a collaboration between AMNH and Scholastic designed to promote science literacy. Written for students in grades 3-6, this article from SuperScience magazine has an interview with AMNH paleontologist Niles Eldredge, in which he explains how the eye-opening sights Charles Darwin encountered during his five-year voyage on the HMS Beagle inspired his thinking about the diversity of life on Earth. There is a hands-on activity, Iguana Puzzle, that challenges students to use clues and photographs to distinguish between a marine and a land iguana.

223

Expedition on the Bay Virtual Voyage  

NSDL National Science Digital Library

This site from Don Reed of San Jose State University is a virtual research cruise that takes viewers on a virtual expedition to acquire and interpret a survey of the San Francisco Bay floor using high resolution seafloor mapping data. The site includes interviews, articles, maps, images, definitions, data acquisition methods, explanations and a site evaluation as the "voyage" proceeds. A student worksheet accompanies the tour of the website. There are also links available for more in-depth study of San Francisco Bay.

Reed, Don; University, San J.

224

Voyager imaging of Triton's clouds and hazes  

NASA Technical Reports Server (NTRS)

Results are presented from a detailed analysis of Voyager images of Triton obtained at the highest solar phase angles; these have been fit to Mie scattering models in order to obtain the mean particle sizes, number densities, and the vertical extent of the two different scattering components of the Triton atmosphere. The 0.001-0.01 optical depths of about 0.17 micron particles are vertically distributed with scale heights of about 10 km throughout Triton. A number of properties of the haze particles in question suggest that they are composed of photochemically produced gases which have condensed in the cold lower atmosphere of Triton.

Rages, Kathy; Pollack, James B.

1992-01-01

225

Introducing krypton NMR spectroscopy as a probe of void space in solids.  

PubMed

A wealth of information about porous materials and their void spaces has been obtained from the chemical shift data in (129)Xe NMR spectroscopy during the past decades. In this contribution, the only NMR active, stable krypton isotope (83)Kr (spin I = (9)/(2)) is explored as a novel probe for porous materials. It is demonstrated that (83)Kr NMR spectroscopy of nanoporous or microporous materials is feasible and straightforward despite the low gyromagnetic ratio and low abundance of the (83)Kr isotope. The (83)Kr line width in most of the studied cases is quadrupolar dominated and field-strength independent. A significant exception was found in calcium-exchanged zeolites where the field dependence of the line width indicates a distribution of isotropic chemical shifts that may be caused by long-range disorder in the zeolite structure. The (83)Kr chemical shifts observed in the investigated materials display a somewhat different behavior than that of their (129)Xe counterparts and should provide a great resource for the verification or refinement of current (129)Xe chemical shift theory. In contrast to xenon, krypton with its smaller atomic radius has been demonstrated to easily penetrate the porous framework of NaA. Chemical shifts and line widths of (83)Kr are moderately dependent on small fluctuations in the krypton loading but differ strongly between some of the studied samples. PMID:15701030

Horton-Garcia, Charlene F; Pavlovskaya, Galina E; Meersmann, Thomas

2005-02-16

226

Plasma observations near Jupiter: initial results from Voyager 1  

Microsoft Academic Search

Extensive measurements of low-energy positive ions and electrons were made throughout the Jupiter encounter of Voyager 1. The bow shock and magnetopause were crossed several times at distances consistent with variations in the upstream solar wind pressure measured on Voyager 2. During the inbound pass, the number density increased by six orders of magnitude between the innermost magnetopause crossing at

H. S. Bridge; J. W. Belcher; A. J. Lazarus; J. D. SULLIVAN; R. L. MCNUTT; F. BAGENAL; J. D. SCUDDER; E. C. SITTLER; G. L. SISCOE; V. M. VASYLIUNAS; C. K. GOERTZ; C. M. YEATES

1979-01-01

227

Radio detection of Uranian lightning by Voyager 2  

Microsoft Academic Search

Within distances of ?600,000 km from Uranus, the Planetary Radio Astronomy experiment aboard the Voyager 2 spacecraft detected impulsive (100 - 300 ms) bursts of broad-band (<=900 kHz to ?40 MHz) radio emission. This emission is very different from the uranian magnetospheric radio component, also discovered during the recent Voyager - Uranus encounter. By analogy with the Saturn electrostatic discharges

P. Zarka; B. M. Pedersen

1986-01-01

228

Plasma waves near Saturn: initial results from Voyager 1  

Microsoft Academic Search

The Voyager 1 encounter with Saturn provided the first opportunity to investigate plasma wave interactions in the magnetosphere of Saturn. An overview of the principal results from the Voyager 1 plasma wave instrument is presented starting with the initial detection of Saturn and ending about four weeks after closest approach. A survey plot of the electric field intensities detected during

D. A. Gurnett; W. S. Kurth; F. L. Scarf

1981-01-01

229

Plasma observations near Neptune - Initial results from Voyager 2  

Microsoft Academic Search

The plasma science experiment on Voyager 2 made observations of the plasma environment in Neptune's magnetosphere and in the surrounding solar wind. Because of the large tilt of the magnetic dipole and fortuitous timing, Voyager entered Neptune's magnetosphere through the cusp region, the first cusp observations at an outer planet. Thus the transition from the magnetosheath to the magnetosphere observed

J. W. Belcher; H. S. Bridge; B. Coppi; G. S. Gordon Jr.; A. J. Lazarus; R. L. McNutt Jr.; F. Bagenal; O. Divers; A. Eviatar; K. W. Ogilvie; L. Villanueva; M. Zhang; E. C. Jr. Sittler; G. L. Siscoe; V. M. Vasyliunas

1989-01-01

230

Spectrophotometric probe  

DOEpatents

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.

Prather, W.S.; O'Rourke, P.E.

1994-08-02

231

Spectrophotometric probe  

SciTech Connect

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.

Prather, William S. (Augusta, GA); O'Rourke, Patrick E. (Martinez, GA)

1994-01-01

232

DSN radio science system design and testing for Voyager-Neptune encounter  

NASA Technical Reports Server (NTRS)

The Deep Space Network (DSN) Radio Science System presently implemented within the Deep Space Network was designed to meet stringent requirements imposed by the demands of the Voyager-Neptune encounter and future missions. One of the initial parameters related to frequency stability is discussed. The requirement, specification, design, and methodology for measuring this parameter are described. A description of special instrumentation that was developed for the test measurements and initial test data resulting from the system tests performed at Canberra, Australia and Usuda, Japan are given.

Ham, N. C.; Rebold, T. A.; Weese, J. F.

1989-01-01

233

A voyage to Mars: A challenge to collaboration between man and machines  

NASA Technical Reports Server (NTRS)

A speech addressing the design of man machine systems for exploration of space beyond Earth orbit from the human factors perspective is presented. Concerns relative to the design of automated and intelligent systems for the NASA Space Exploration Initiative (SEI) missions are largely based on experiences with integrating humans and comparable systems in aviation. The history, present status, and future prospect, of human factors in machine design are discussed in relation to a manned voyage to Mars. Three different cases for design philosophy are presented. The use of simulation is discussed. Recommendations for required research are given.

Statler, Irving C.

1991-01-01

234

Voyager engineering improvements for Uranus encounter  

NASA Technical Reports Server (NTRS)

Engineering changes made on the Voyager spacecraft during their explorations of the outer solar system are discussed. A recovery from a scan actuator fault, achieved by ground testing, in flight capability enhancement and testing, conservation of actuator usage and a set of contingency plans to substitute roll motion of the spacecraft for motion of the scan platform in the AZ direction, is discussed. General engineering improvements made are addressed, including a scan platform anticreep patch modification, an improvement of dynamic performance during maneuvers, and adaptive control of the attitude control deadband. Changes made in the power management are described. Finally, engineering improvements made in order to enhance scientific findings at the Uranus encounter are reviewed in detail. The two most important were the increased gyro drift turn rate capability to accommodate image motion compensation for the close fly-by of Miranda and the reduction in spacecraft rates to accommodate increased imaging exposure times without incurring excessive image smear.

Marderness, H. P.

1986-01-01

235

Color Voyager 2 Image Showing Crescent Uranus  

NASA Technical Reports Server (NTRS)

This image shows a crescent Uranus, a view that Earthlings never witnessed until Voyager 2 flew near and then beyond Uranus on January 24, 1986. This planet's natural blue-green color is due to the absorption of redder wavelengths in the atmosphere by traces of methane gas. Uranus' diameter is 32,500 miles, a little over four times that of Earth. The hazy blue-green atmosphere probably extends to a depth of around 5,400 miles, where it rests above what is believed to be an icy or liquid mixture (an 'ocean') of water, ammonia, methane, and other volatiles, which in turn surrounds a rocky core perhaps a little smaller than Earth.

1990-01-01

236

Voyager 1 Jupiter Southern Hemisphere Movie  

NASA Technical Reports Server (NTRS)

This movie shows a portion of Jupiter in the southern hemisphere over 17Jupiter days. Above the white belt, notice the series of atmospheric vortices headed west. Even these early approach frames show wild dynamics in the roiling environment south of the white belt. Notice the small tumbling white cloud near the center.

As Voyager 1 approached Jupiter in 1979, it took images of the planet at regular intervals. This sequence is made from 17 images taken once every Jupiter rotation period (about 10 hours). These images were acquired in the Blue filter around Feb. 1, 1979. The spacecraft was about 37 million kilometers from Jupiter at that time.

This time-lapse movie was produced at JPL by the Image Processing Laboratory in 1979.

2000-01-01

237

EarthScope Voyager: Did You Know?  

NSDL National Science Digital Library

Visitors to this site will learn about some of the most geologically active areas in North America, such as the Long Valley Caldera of California and the Basin and Range province of the Western United States. Each study area features information on its tectonic and volcanic history as well as its geologic hazards. For example, users learn that thousands of people every year ski on an active volcano in the Long Valley Caldera, and that toxic gases generated by this volcano are seeping out of the ground. The 'Explore!' section for each study area has questions for users to explore in the EarthScope Voyager interactive map tool. A final section describes the scientific problems that the EarthScope Project is investigating in the area. EarthScope is a bold undertaking to apply modern observational, analytical, and telecommunications technologies to investigate the structure and evolution of the North American continent and the physical processes controlling earthquakes and volcanic eruptions.

238

Voyages and Travels: Ancient and Modern  

NSDL National Science Digital Library

Sir Walter Raleigh was a man who liked to travel the globe. He was in good company, as persons stretching all the way back to Herodotus (and before) had a certain wanderlust that could only be quenched by seeking out new lands and experiences. Some of their musings on the places they explored can be found within the electronic pages of the volume presented here by Bartleby.com. The Voyages and Travels work was originally part of the Harvard Classics series, and it contains seven accounts of travel and exploration. These accounts include "An Account of Egypt" by Herodotus, Sir Walter Raleigh's "The Discovery of Guiana", and a narrative of Sir Humphrey Gilbert's trip to Newfoundland in the 16th century.

239

Ultraviolet spectrometer experiment for the Voyager mission  

NASA Technical Reports Server (NTRS)

An objective grating spectrometer covering the wavelength range of 500 to 1700 A with a 10-A resolution is employed for the Voyager ultraviolet spectrometer experiment. In determining the composition and structure of the atmospheres of Saturn, Jupiter and several satellites, the ultraviolet spectrometer will rely on airglow mode observations to measure radiation from the atmospheres due to resonant scattering of solar flux, and the occultation mode for assessments of the atmospheric extinction of solar or stellar radiation as the spacecraft enters shadow zones. Since it is capable of prolonged stellar observations in the 500 to 1000 A wavelength range, the spectrometer is expected to make important contributions to exploratory studies of UV sources.

Broadfoot, A. L.; Sandel, B. R.; Shemansky, D. E.; Atreya, S. K.; Donahue, T. M.; Moos, H. W.; Bertaux, J. L.; Blamont, J. E.; Ajello, J. M.; Strobel, D. F.

1977-01-01

240

The RF Probe: providing space situational awareness through broad-spectrum detection and characterization  

Microsoft Academic Search

AeroAstro's patented RF Probe is a system designed to address the needs of spacecraft developers and operators interested in measuring and analyzing near-field RF emissions emanating from a nearby spacecraft of interest. The RF Probe consists of an intelligent spectrum analyzer with digital signal processing capabilities combined with a calibrated, wide-bandwidth antenna and RF front end that covers the 50

Raymond Zenick; Kimberly Kohlhepp; Russell Partch

2004-01-01

241

New Developments in the Hunveyor-Husar Educational Space Probe Model System of Hungarian Universities: New Atlas in the Series of the Solar System  

Microsoft Academic Search

The new atlas on Hunveyor-Husar models studies: 1) The system of planetary materials research and constructive works with space probes, 2) Hunveyor developments, 3) Husar developments, 4) Mars analog site studies in Hungary and Utah.

S. Hegyi; Gy. Hudoba; H. Hargitai; Z. Balogh; T. Biró; I. Bornemisza; A. Kókány; A. Geresdi; G. Sasvári; R. Senyei; T. Varga; Sz. Bérczi

2007-01-01

242

On the accuracy of the relativistic parameters beta, gamma, and the solar oblateness coefficient J2, as deduced from ranging data of a drag-free space probe  

NASA Technical Reports Server (NTRS)

Motion in the general gravity field is described mathematically. A covariance analysis, based on two simple models, is presented. Two drag-free space probes were considered, for which the orbital elements are given.

Roth, E. A.

1971-01-01

243

Chemistry Experiments — For Comparative Analyses for Demonstrating Environmental Differences on Venus, Earth, Mars and Titan, — Built on Educational Space Probes Hunveyor and Husar  

NASA Astrophysics Data System (ADS)

We compared chemical environments of Venus, Earth, Mars and Titan by experiments planned for selection to realize them on educational space probe landers and rovers (Hunveyor and Husar) built by Hungarian universities and high schools.

Bérczi, Sz.; Róka, A.; Nyíri, Z.; Varga, T.; Fabriczy, A. Sz.; Peták, Cs.; Hudoba, Gy.; Hegyi, S.; Lang, A.; Gyollai, I.; Gucsik, A.

2014-11-01

244

Saturn radio emission and the solar wind - Voyager-2 studies  

NASA Technical Reports Server (NTRS)

Voyager 2 data from the Plasma Science experiment, the Magnetometer experiment and the Planetary Radio Astronomy experiment were used to analyze the relationship between parameters of the solar wind/interplanetary medium and the nonthermal Saturn radiation. Solar wind and interplanetary magnetic field properties were combined to form quantities known to be important in controlling terrestrial magnetospheric processes. The Voyager 2 data set used in this investigation consists of 237 days of Saturn preencounter measurements. However, due to the immersion of Saturn and the Voyager 2 spacecraft into the extended Jupiter magnetic tail, substantial periods of the time series were lacking solar wind data. To cope with this problem a superposed epoch method (CHREE analysis) was used. The results indicate the superiority of the quantities containing the solar wind density in stimulating the radio emission of Saturn - a result found earlier using Voyager 1 data - and the minor importance of quantities incorporating the interplanetary magnetic field.

Desch, M. D.; Rucker, H. O.

1985-01-01

245

The Voyager Spacecraft. [Jupiter-Saturn mission investigations  

NASA Technical Reports Server (NTRS)

The configuration of the Voyager spacecraft is described as well as the subsystems for power, temperature control, attitude control, and propulsion. Major features of Jupiter and Saturn including their atmospheres, surfaces, and natural satellites are discussed. The 13 onboard experiments and their scientific objectives are explained. Other aspects covered include tracking, data acquisition, and the mission control and computing center. Members of the Voyager team and subcontractors are listed.

1979-01-01

246

Lick Saturn-Voyager Reference Star Catalogue (Klemola+, 1979)  

Microsoft Academic Search

The Lick Saturn-Voyager Reference Star Catalogue was prepared for purposes of determining up-to-date, reasonably accurate, equatorial coordinates for reference stars in a band of sky against which cameras of the Voyager spacecraft were aligned for observations in the region of Saturn during the flyby. The requirements were a surface density of about three reference stars per observation frame of 24

A. R. Klemola; H. Taraji; A. Ocampo

1995-01-01

247

Triton and Nereid astrographic observations from Voyager 2  

NASA Technical Reports Server (NTRS)

This article describes the reduced astrographic observations of Triton and Nereid derived from Voyager 2 imaging data. The data set contains 496 sets of spacecraft-centered fight ascension and declination observations and includes all of the observations used in Voyager encounter operations. The details of the conversion process from imaging to astrographic observations are given. The effect of using the astrographic rather than imaging form in ephemeris improvement is evaluated.

Jacobson, R. A.

1991-01-01

248

Sealing scientific probes against deep space and the Venusian environment A tough job  

NASA Technical Reports Server (NTRS)

The Pioneer Venus mission evolved from studies conducted during the late 1960s and early 1970s. It was found that a need existed for low cost orbiters and landers to explore the planet. The considered mission was to be accomplished with six separate vehicles arriving at Venus nearly simultaneously in mid-December 1978. The probes are designed to survive entry and descent into the atmosphere. A description is presented of the approaches used to maintain sealing integrity for the large and small probes under the constraints imposed by the harsh Venusian environment. Attention is given to probe vehicle configuration, pressure vessel sealing requirements, material and configuration considerations, permanent seals, separable seals, development problems, and aspects of seal testing.

Pokras, J.; Reinert, R. P.; Switz, R. J.

1978-01-01

249

Accurate shape description of flexible beam undergoing oblique impact based on space probe-cone docking mechanism  

NASA Astrophysics Data System (ADS)

The purpose of this paper is to do some researches on the accurate shape description of flexible beam undergoing oblique impact based on space probe-cone docking mechanism. The docking dynamics model is built based on Lagrange analytical method. Accurate modal equations of rigid-flexible coupling system, which include modified modal equations and modal frequencies, are derived. The MSC.Patran/Dytran is introduced to be the simulation tool. Third models with different parameters are built by both theoretical method and finite element method to verify the correctness of the new modal equations of rigid-flexible coupling system.

Zhang, Xiang; Huang, Yiyong; Han, Wei; Chen, Xiaoqian

2013-09-01

250

Cosmic ray measurements aboard the Mars 4, 5, 6, and 7 space probes  

Microsoft Academic Search

Some of the outstanding features of the cosmic ray measurements transmitted from four Mars probes, which were launched in 1973 and either flew by Mars or orbited the planet, are pointed out. The largest increase in the solar cosmic ray flux was recorded on Sept. 7, 1973, indicating the production of particles with energies greater than 500 MeV on the

E. Ia. Volodin; I. V. Getselev; E. V. Gorchakov; A. V. Dunaevskii; V. A. Iozenas; P. P. Ignatev; N. N. Kontor; G. P. Liubimov; Iu. A. Rozental; M. V. Ternovskaia

1977-01-01

251

A Computational Analysis of Galactic Exploration with Space Probes: Implications for the Fermi Paradox  

Microsoft Academic Search

Temporal explanations to the Fermi paradox state that the vast scale of the galaxy diminishes the chances of establishing contact with an extraterrestrial technological civilization (ETC) within a certain time window. This argument is tackled in this work in the context of exploration probes, whose propagation can be faster than that of a colonization wavefront. Extensive computational simulations have been

Carlos Cotta; Álvaro Morales

2009-01-01

252

1958 NASA/USAF Space Probes (ABLE-1). Volume 3; Vehicles, Trajectories, and Flight Histories  

NASA Technical Reports Server (NTRS)

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.

1959-01-01

253

1958 NASA/USAF Space Probes (ABLE-1). Volume 2; Payload and Experiments  

NASA Technical Reports Server (NTRS)

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.

1959-01-01

254

Gravity Probe B: Examining Einstein's Spacetime with Gyroscopes. An Educator's Guide with Activities in Space Science.  

ERIC Educational Resources Information Center

This teaching guide introduces a relativity gyroscope experiment aiming to test two unverified predictions of Albert Einstein's general theory of relativity. An introduction to the theory includes the following sections: (1) "Spacetime, Curved Spacetime, and Frame-Dragging"; (2) "'Seeing' Spacetime with Gyroscopes"; (3) "The Gravity Probe B…

Range, Shannon K'doah; Mullins, Jennifer

255

The helium abundance of Jupiter from Voyager  

NASA Technical Reports Server (NTRS)

Full disk measurements recorded 31 days before the Voyager 1 encounter with Jupiter by the radiometer of the infrared instrument, IRIS, indicate a geometric albedo of 0.274 + or - 0.013. Combining this measurement with the Pioneer derived phase integral of 1.25 and our error estimate of 0.1 yields a Jovian Bond albedo of 0.343 + or - 0.032. Infrared spectra recorded at the same time by the Michelson interferometer, along with a model extrapolation to low wave numbers not covered by the instrument, yield a thermal emission of (1.359 + or - 0.014) .001 W cm to the (-2) power. As in the case of the albedo measurement, the quoted errors in the emission measurement reflect estimates of systematic effects and are uncertain while the random component is negligible. From these measurements the internal heat flux of Jupiter is estimated to be (5.444 + or - 0.425) .0001 W cm to the (-2) power, and the energy balance defined as the ratio of emitted thermal to absorbed solar energy is 1.668 + or - 0.085.

Gautier, D.; Conrath, B.; Flasar, F. M.; Hanel, R. A.; Kunde, V. G.; Chedin, A.; Scott, N.

1980-01-01

256

New Voyager radio spectrograms of Uranus  

NASA Technical Reports Server (NTRS)

New, high-resolution spectrograms of the Voyager-2 radio observations at Uranus were produced from the original, six-second Planetary Radio Astronomy (PRA) data and these show a number of new features which were not obvious in previous versions. Among these new features are the detailed structure of the so-called broadband-bursty (b-bursty) emissions, unexpected sloping striations in the smooth high-frequency (SHF) component, and the overlap of these two components during the first rotation after closest approach. In addition, a slightly different planetary rotation rate from the b-bursty emissions, was found, and at the initial onset of the SHF component, what appears to be the shadow of a Uranian plasmasphere. These new spectrograms were prepared using a special dithering algorithm to show signal strengths as gray shadings, and the data were also manually cleaned to suppress noise and interference. This produced spectrograms of exceptional quality and certain details of their production on a stand-alone personal computer are also discussed.

Calvert, W.; Tsintikidis, D.

1990-01-01

257

Radial space potential measurements in the central cell of the tandem mirror experiment with a heavy-ion-beam probe  

SciTech Connect

Spatial and temporal profiles of the space potential in the central-cell midplane of TMX have been obtained with a heavy-ion-beam probe. The absolute accuracy of measurements is +- 25 volts (with respect to the machine vacuum walls) with a resolution of approx. 2 volts. During moderate fueling with the gas boxes (i/sub gas/ approx. = 1200 Atom-Amperes D/sub 2/), the plasma potential is parabolic to at least 25 cm radius, with phi/sub e/ approx. = phi/sub max/(1-(r/32)/sup 2/) and 300 < phi/sub max/ <450 volts. With puffer-valve fueling, the space potential is relatively flat to at least 27 cm radius, with 250 < phi/sub e/ < 350 volts.

Hallock, G.A.

1983-04-11

258

What Does the Edge of the Solar System Look Like? Ask Voyager  

NSDL National Science Digital Library

After twenty six years of travel, Voyager is setting a new record -- it will soon, if not already, pass through the bubble that surrounds our solar system. At this Web site, Rachel Weintraub at NASA Goddard Space Flight Center recaps the successes of the mission, which include providing the first views of volcanoes on Jupiter and close-ups of Saturn's rings. Users will find animations that represent the image scientists have of the theoretical boundary around our solar system. The Web site also addresses two science teams' different interpretations of the data being gathered, giving visitors a sense of the uncertainty scientists cope with when they create and modify theories.

259

Voyager investigation of the cosmic diffuse background: Observations of rocket-studied locations with Voyager  

NASA Technical Reports Server (NTRS)

Attachments to this final report include 2 papers connected with the Voyager work: 'Voyager Observations of Dust Scattering Near the Coalsack Nebula' and 'Search for the Intergalactic Medium'. An appendix of 12 one-page write-ups prepared in connection with another program, UVISI, is also included. The one-page write-ups are: (1) Sky survey of UV point sources to 600 times fainter than previous (TD-1) survey; (2) Diffuse galactic light: starlight scattered from dust at high galactic latitude; (3) Optical properties of interstellar grains; (4) Fluorescence of molecular hydrogen in the interstellar medium; (5) Line emission from hot interstellar medium and/or hot halo of galaxy; (6) Integrated light of distant galaxies in the ultraviolet; (7) Intergalactic far-ultraviolet radiation field; (8) Radiation from recombining intergalactic medium; (9) Radiation from re-heating of intergalactic medium following recombination; (10) Radiation from radiative decay of dark matter candidates (neutrino, etc.); (11) Reflectivity of the asteroids in the Ultraviolet; and (12) Zodiacal light.

Henry, Richard C.

1994-01-01

260

Study of sensor positioning in the space for probe abdominal echographics  

Microsoft Academic Search

This paper describes an ultrasonic spatial localization system for a sonometric probe, to build 3D images of a fetus. The main objective of such a system is a medical diagnostic help. A method to improve accuracy of ultrasonic telemeter is developed and gives us encouraging results. We arrive to measure a distance with accuracy around 0.6 mm for 1.5 meters

Abdelmalik Taleb-Ahmed; Eric Duquenoy; Philippe Frere; Y. Beral

1996-01-01

261

Fiber-Optic Imaging Probe Developed for Space Used to Detect Diabetes Through the Eye  

NASA Technical Reports Server (NTRS)

Approximately 16 million Americans have diabetes mellitus, which can severely impair eyesight by causing cataracts, diabetic retinopathy, and glaucoma. Cataracts are 1.6 times more common in people with diabetes than in those without diabetes, and cataract extraction is the only surgical treatment. In many cases, diabetes-related ocular pathologies go undiagnosed until visual function is compromised. This ongoing pilot project seeks to study the progression of diabetes in a unique animal model by monitoring changes in the lens with a safe, sensitive, dynamic light-scattering probe. Dynamic light scattering (DLS), has the potential to diagnose cataracts at the molecular level. Recently, a new DLS fiber-optic probe was developed at the NASA Glenn Research Center at Lewis Field for noncontact, accurate, and extremely sensitive particle-sizing measurements in fluid dispersions and suspensions (ref. 1). This compact, portable, and rugged probe is free of optical alignment, offers point-and-shoot operation for various online field applications and challenging environments, and yet is extremely flexible in regards to sample container sizes, materials, and shapes. No external vibration isolation and no index matching are required. It can measure particles as small as 1 nm and as large as few micrometers in a wide concentration range from very dilute (waterlike) dispersions to very turbid (milklike) suspensions. It is safe and fast to use, since it only requires very low laser power (10 nW to 3 mW) with very short data acquisition times (2 to 10 sec).

Ansari, Rafat R.; Chenault, Michelle V.; Datiles, Manuel B., III; Sebag, J.; Suh, Kwang I.

2000-01-01

262

The Use of Langmuir Probes in Non-Maxwellian Space Plasmas  

NASA Technical Reports Server (NTRS)

Disturbance of the Maxwellian plasma may occur in the vicinity of a spacecraft due to photoemission, interactions between the spacecraft and thermospheric gases, or electron emissions from other devices on the spacecraft. Significant non-maxwellian plasma distributions may also occur in nature as a mixture of ionospheric and magnetospheric plasmas or secondaries produced by photoionization in the thermosphere or auroral precipitation. The general formulas for current collection (volt-ampere curves) by planar, cylindrical, and spherical Langmuir probes in isotropic and anisotropic non-maxwellian plasmas are examined. Examples are given of how one may identify and remove the non-maxwellian components in the Langmuir probe current to permit the ionospheric parameters to be determined. Theoretical volt-ampere curves presented for typical examples of non-maxwellian distributions include: two-temperature plasmas and a thermal plasma with an energetic electron beam. If the non-ionospheric electrons are Maxwellian at a temperature distinct from that of the ionosphere electrons, the volt-ampere curves can be fitted directly to obtain the temperatures and densities of both electron components without resorting to differenting the current. For an arbitrary isotropic distribution, the current for retarded particles is shown to be identical for the three geometries. For anisotropic distributions, the three probe geometries are not equally suited for measuring the ionospheric electron temperature and density or for determining the distribution function in the presence of non-maxwellian back-round electrons.

Hoegy, Walter R.; Brace, Larry H.

1998-01-01

263

In vitro cultured cells as probes for space radiation effects on biological systems.  

PubMed

Near future scenarios of long-term and far-reaching manned space missions, require more extensive knowledge of all possible biological consequences of space radiation, particularly in humans, on both a long-term and a short-term basis. In vitro cultured cells have significantly contributed to the tremendous advancement of biomedical research. It is therefore to be expected that simple biological systems such as cultured cells, will contribute to space biomedical sciences. Space represents a novel environment, to which life has not been previously exposed. Both microgravity and space radiation are the two relevant components of such an environment, but biological adaptive mechanisms and efficient countermeasures can significantly minimize microgravity effects. On the other hand, it is felt that space radiation risks may be more relevant and that defensive strategies can only stem from our deeper knowledge of biological effects and of cellular repair mechanisms. Cultured cells may play a key role in such studies. Particularly, thyroid cells may be relevant because of the exquisite sensitivity of the thyroid gland to radiation. In addition, a clone of differentiated, normal thyroid follicular cells (FRTL5 cells) is available in culture, which is well characterized and particularly fit for space research. PMID:10631337

Meli, A; Perrella, G; Curcio, F; Ambesi-Impiombato, F S

1999-12-01

264

Voyager 2 observations of plasma in the heliosheath  

NASA Astrophysics Data System (ADS)

Voyager 2 is now at 96 AU and provides the only direct observations of plasma in the heliosheath. I will present the most recent plasma observations and try to assimilate them with other Voyager measurements and observations at 1 AU. The heliosheath is highly variable on scales of tens of minutes in both plasma and magnetic field parameters. The distribution of plasma parameters is Gaussian; this enables us to determine flow directions as the flow angles approach the instrument cutoff. The plasma speeds observed at Voyager 2 remain well above those inferred at Voyager 1 at similar distances into the heliosheath. The Voyager 2 flows continue to divert toward the heliotail. The direction of flow is more in the T than N direction (using the RTN coordinate system). The density and temperature have decreased across the heliosheath until the beginning of 2011; since then the density has increased by a factor of 2 and the speed and temperature have also increased. These results will be compared to model predictions.

Richardson, J. D.

2011-12-01

265

Improvements in Electron-Probe Microanalysis: Applications to Terrestrial, Extraterrestrial, and Space-Grown Materials  

NASA Technical Reports Server (NTRS)

Improvement in the accuracy of electron-probe microanalysis (EPMA) has been accomplished by critical assessment of standards, correction algorithms, and mass absorption coefficient data sets. Experimental measurement of relative x-ray intensities at multiple accelerating potential highlights errors in the absorption coefficient. The factor method has been applied to the evaluation of systematic errors in the analysis of semiconductor and silicate minds. Accurate EPMA of Martian soil stimulant is necessary in studies that build on Martian rover data in anticipation of missions to Mars.

Carpenter, Paul; Armstrong, John

2004-01-01

266

Gamma ray burst delay times probe the geometry of momentum space  

E-print Network

We study the application of the recently proposed framework of relative locality to the problem of energy dependent delays of arrival times of photons that are produced simultaneously in distant events such as gamma ray bursts. Within this framework, possible modifications of special relativity are coded in the geometry of momentum space. The metric of momentum space codes modifications in the energy momentum relation, while the connection on momentum space describes possible non-linear modifications in the laws of conservation of energy and momentum. In this paper, we study effects of first order in the inverse Planck scale, which are coded in the torsion and non-metricity of momentum space. We find that time delays of order Distance * Energies/m_p are coded in the non-metricity of momentum space. Current experimental bounds on such time delays hence bound the components of this tensor of order 1/m_p. We also find a new effect, whereby photons from distant sources can appear to arrive from angles slightly off the direction to the sources, which we call gravitational lensing. This is found to be coded into the torsion of momentum space.

Laurent Freidel; Lee Smolin

2011-03-29

267

33 CFR 169.210 - Where during its international voyage must a ship transmit position reports?  

...Where during its international voyage must a ship transmit position reports? 169.210...CONTINUED) PORTS AND WATERWAYS SAFETY SHIP REPORTING SYSTEMS Transmission of Long...Where during its international voyage must a ship transmit position reports? The...

2014-07-01

268

33 CFR 169.210 - Where during its international voyage must a ship transmit position reports?  

Code of Federal Regulations, 2011 CFR

...Where during its international voyage must a ship transmit position reports? 169.210...CONTINUED) PORTS AND WATERWAYS SAFETY SHIP REPORTING SYSTEMS Transmission of Long...Where during its international voyage must a ship transmit position reports? The...

2011-07-01

269

33 CFR 169.210 - Where during its international voyage must a ship transmit position reports?  

Code of Federal Regulations, 2013 CFR

...Where during its international voyage must a ship transmit position reports? 169.210...CONTINUED) PORTS AND WATERWAYS SAFETY SHIP REPORTING SYSTEMS Transmission of Long...Where during its international voyage must a ship transmit position reports? The...

2013-07-01

270

33 CFR 169.210 - Where during its international voyage must a ship transmit position reports?  

Code of Federal Regulations, 2010 CFR

...Where during its international voyage must a ship transmit position reports? 169.210...CONTINUED) PORTS AND WATERWAYS SAFETY SHIP REPORTING SYSTEMS Transmission of Long...Where during its international voyage must a ship transmit position reports? The...

2010-07-01

271

33 CFR 169.210 - Where during its international voyage must a ship transmit position reports?  

Code of Federal Regulations, 2012 CFR

...Where during its international voyage must a ship transmit position reports? 169.210...CONTINUED) PORTS AND WATERWAYS SAFETY SHIP REPORTING SYSTEMS Transmission of Long...Where during its international voyage must a ship transmit position reports? The...

2012-07-01

272

15 CFR 970.2501 - Notice of pre-license exploration voyages.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Notice of pre-license exploration voyages. 970.2501...MINING REGULATIONS FOR EXPLORATION LICENSES Pre-license Exploration § 970.2501 Notice of pre-license exploration voyages. (a)...

2010-01-01

273

Probing Galaxy Formation and Evolution with Space Born Sub-Millimeter Telescopes  

NASA Technical Reports Server (NTRS)

A major unresolved question in cosmology is how the complex system of galaxies we see in the present universe evolved from an almost perfectly smooth beginning. Multiwavelength observations of galaxies have revealed that a significant fraction of their UV-visible starlight is absorbed and reradiated by dust at infrared JR) and submillimeter wavelengths. The cumulative IR-submm. emission from galaxies since the epoch of recombination, the cosmic IR background, has recently been recorded by the COBE satellite. The COBE observations in combination with recent submm surveys conducted with the SCUBA on the 15 m JCMT have shown that most of the radiation from star formation that has taken place in the early stages of galaxy evolution is reradiated by dust at submm wavelengths. Therefore, submm telescopes offer a unique probe of the early stages of galaxy formation and evolution. This talk will: (1) consider the impact of telescope diameter on the depth of the survey (what redshift can be probed) at different wavelengths; (2) discuss the relative scientific merits of high-resolution narrow-field surveys versus lower resolution deep surveys; and (3) show how both strategies offer complementary information crucial to our understanding of the structure and evolution of galaxies in the universe.

Dwek, Eli; Arendt, Richard G.; Moseley, Harvey; Benford, Dominic; Shafer, Richard; Mather, John; Oegerle, William (Technical Monitor)

2002-01-01

274

Probing phase-space noncommutativity through quantum mechanics and thermodynamics of free particles and quantum rotors  

E-print Network

Novel quantization properties related to the state vectors and the energy spectrum of a two-dimensional system of free particles are obtained in the framework of noncommutative (NC) quantum mechanics (QM) supported by the Weyl-Wigner formalism. Besides reproducing the magnetic field aspect of a Zeeman-like effect, the momentum space NC parameter introduces mutual information properties quantified by the quantum purity related to the relevant coordinates of the corresponding Hilbert space. Supported by the QM in the phase-space, the thermodynamic limit is obtained, and the results are extended to three-dimensional systems. The noncommutativity imprints on the thermodynamic variables related to free particles are identified and, after introducing some suitable constraints to fix an axial symmetry, the analysis is extended to two- and- three dimensional quantum rotor systems, for which the quantization aspects and the deviation from standard QM results are verified.

Catarina Bastos; Alex E. Bernardini; Jonas F. G. Santos

2014-11-11

275

Probing phase-space noncommutativity through quantum mechanics and thermodynamics of free particles and quantum rotors  

E-print Network

Novel quantization properties related to the state vectors and the energy spectrum of a two-dimensional system of free particles are obtained in the framework of noncommutative (NC) quantum mechanics (QM) supported by the Weyl-Wigner formalism. Besides reproducing the magnetic field aspect of the Zeeman effect, the momentum space NC parameter introduces mutual information properties quantified by the linear entropy related to the relevant Hilbert space coordinates. Supported by the QM in the phase-space, the thermodynamic limit is obtained, and the results are extended to three-dimensional systems. The noncommutativity imprints on the thermodynamic variables related to free particles are identified and, after introducing some suitable constraints to fix an axial symmetry, the analysis is extended to two- and- three dimensional quantum rotor systems, for which the quantization aspects and the deviation from standard QM results are verified.

Bastos, Catarina; Santos, Jonas F G

2014-01-01

276

Astrographic observations of the major Uranian satellites from Voyager 2  

NASA Technical Reports Server (NTRS)

This article provides the reduced astrographic observations of the major Uranian satellites derived from star-satellite imaging data acquired by the Voyager 2 spacecraft. The data set contains 445 sets of spacecraft-centered right ascension and declination observations and includes all of the observations used in Voyager encounter operations. The conversion process from imaging to astrographic observations was identical to that used for the Neptunian satellites (Jacobson 1991). The effect of using the astrographic rather than imaging form in ephemeris improvement is evaluated.

Jacobson, R. A.

1992-01-01

277

Astrographic observations of the major Uranian satellites from Voyager 2  

NASA Astrophysics Data System (ADS)

This article provides the reduced astrographic observations of the major Uranian satellites derived from star-satellite imaging data acquired by the Voyager 2 spacecraft. The data set contains 445 sets of spacecraft-centered right ascension and declination observations and includes all of the observations used in Voyager encounter operations. The conversion process from imaging to astrographic observations was identical to that used for the Neptunian satellites (Jacobson 1991). The effect of using the astrographic rather than imaging form in ephemeris improvement is evaluated.

Jacobson, R. A.

1992-12-01

278

Magnetic field studies at Jupiter by Voyager 2: Preliminary results  

NASA Technical Reports Server (NTRS)

The Voyager 2 magnetic field experiment is described and compared to the Voyager 1 experiment and data. The magnetosphere, the bow shock, the magnetopause, and the extended magnetic tail of Jupiter are discussed. Two crossings of the near equatorial current sheet were observed in the magnetosphere and its tail every 10 hour rotation period of the planet. A definitive mapping of the geometry and character of these enhanced plasma and depressed magnetic field regions is discussed. The interaction of the satellite Ganymede with the Jovian magnetosphere, which leads to disturbances as the Jovian magnetosphere corotates with the planet past the satellite is analyzed.

Ness, N. F.; Acuna, M. H.; Lepping, R. P.; Burlaga, L. F.; Behannon, K. W.; Neubauer, F. M.

1979-01-01

279

Performance model of the Argonne Voyager multimedia server  

SciTech Connect

The Argonne Voyager Multimedia Server is being developed in the Futures Lab of the Mathematics and Computer Science Division at Argonne National Laboratory. As a network-based service for recording and playing multimedia streams, it is important that the Voyager system be capable of sustaining certain minimal levels of performance in order for it to be a viable system. In this article, the authors examine the performance characteristics of the server. As they examine the architecture of the system, they try to determine where bottlenecks lie, show actual vs potential performance, and recommend areas for improvement through custom architectures and system tuning.

Disz, T.; Olson, R.; Stevens, R. [Argonne National Lab., IL (United States). Mathematics and Computer Science Div.

1997-07-01

280

Radio science ground data system for the Voyager-Neptune encounter, part 1  

NASA Technical Reports Server (NTRS)

The Voyager radio science experiments at Neptune required the creation of a ground data system array that includes a Deep Space Network complex, the Parkes Radio Observatory, and the Usuda deep space tracking station. The performance requirements were based on experience with the previous Voyager encounters, as well as the scientific goals at Neptune. The requirements were stricter than those of the Uranus encounter because of the need to avoid the phase-stability problems experienced during that encounter and because the spacecraft flyby was faster and closer to the planet than previous encounters. The primary requirement on the instrument was to recover the phase and amplitude of the S- and X-band (2.3 and 8.4 GHz) signals under the dynamic conditions encountered during the occultations. The primary receiver type for the measurements was open loop with high phase-noise and frequency stability performance. The receiver filter bandwidth was predetermined based on the spacecraft's trajectory and frequency uncertainties.

Kursinski, E. R.; Asmar, S. W.

1991-01-01

281

Considerations Affecting Satellite and Space Probe Research with Emphasis on the "Scout" as a Launch Vehicle  

NASA Technical Reports Server (NTRS)

This report reviews a number of the factors which influence space flight experiments. Included are discussions of payload considerations, payload design and packaging, environmental tests, launch facilities, tracking and telemetry requirements, data acquisition, processing and analysis procedures, communication of information, and project management. Particular emphasis is placed on the "Scout" as a launching vehicle. The document includes a description of the geometry of the "Scout" as well as its flight capabilities and limitations. Although oriented toward the "Scout" vehicle and its payload capabilities, the information presented is sufficiently general to be equally applicable to most space vehicle systems.

Posner, Jack (Editor)

1961-01-01

282

Availability of feature-oriented scanning probe microscopy for remote-controlled measurements on board a space laboratory or planet exploration Rover.  

PubMed

Prospects for a feature-oriented scanning (FOS) approach to investigations of sample surfaces, at the micrometer and nanometer scales, with the use of scanning probe microscopy under space laboratory or planet exploration rover conditions, are examined. The problems discussed include decreasing sensitivity of the onboard scanning probe microscope (SPM) to temperature variations, providing autonomous operation, implementing the capabilities for remote control, self-checking, self-adjustment, and self-calibration. A number of topical problems of SPM measurements in outer space or on board a planet exploration rover may be solved via the application of recently proposed FOS methods. PMID:19566423

Lapshin, Rostislav V

2009-06-01

283

The atmosphere of Titan - an analysis of the Voyager 1 radio occultation measurements  

NASA Astrophysics Data System (ADS)

The equatorial atmosphere of Titan was probed by means of two coherently related radio signals transmitted from Voyager 1 at 13.0 and 3.6 cm wavelengths during the November 12, 1980 occultation of the spacecraft by the Saturn satellite. An analysis of the differential dispersive frequency measurements did not reveal any ionization layers in the upper atmosphere of Titan. The gas refractivity data, which extend from the surface to about 200 km altitude, were interpreted in two different ways. In the first, it is assumed that N2 makes up virtually all of the atmosphere, with small amounts of CH4 and other hydrocarbons present. In the second interpretation of the refractivity data, it is assumed that the 3.5 km altitude level corresponds to the bottom of a CH4 cloud layer and that N2 and CH4 were perfectly mixed below this level.

Lindal, G. F.; Wood, G. E.; Hotz, H. B.; Sweetnam, D. N.; Eshleman, V. R.; Tyler, G. L.

1983-02-01

284

Photons with sub-Planckian energy cannot efficiently probe space-time foam  

NASA Astrophysics Data System (ADS)

Extra-galactic sources of photons have been used to constrain space-time quantum fluctuations in the Universe. In these proposals, the fundamental "fuzziness" of distance caused by space-time quantum fluctuations has been directly identified with fluctuations in optical paths. Phase-front corrugations deduced from these optical-path fluctuations are then applied to light from extra-galactic point sources, and used to constrain various models of quantum gravity. However, when a photon propagates in three spatial dimensions, it does not follow a specific ray, but rather samples a finite, three-dimensional region around that ray—thereby averaging over space-time quantum fluctuations all through that region. We use a simple, random-walk type model to demonstrate that, once the appropriate wave optics is applied, the averaging of neighboring space-time fluctuations will cause much less distortion to the phase front. In our model, the extra suppression factor due to diffraction is the wave length in units of the Planck length, which is at least 1029 for astronomical observations.

Chen, Yanbei; Wen, Linqing; Ma, Yiqiu

2014-09-01

285

Cosmic rays and TeV photons as probes of quantum properties of space-time  

E-print Network

It has been recently observed that small violations of Lorentz invariance, of a type which may arise in quantum gravity, could explain both the observations of cosmic rays above the GZK cutoff and the observations of 20-TeV gamma rays from Markarian 501. We show here that different pictures of the short-distance structure of space-time would lead to different manifestations of Lorentz-invariance violation. Specifically, the deformation of Lorentz invariance needed to resolve these observational paradoxes can only arise within commutative short-distance pictures of space-time. In noncommutative space-times there is no anomalous effect, at least at leading order. Also exploiting the fact that arrival-time delays between high energy photons with different energies would arise in both the commutative and the noncommutative Lorentz-violation pictures, we describe an experimental programme, based on time-of-arrival analysis of high energy photons and searches of violations of GZK and TeV-photon limits, which could discriminate between alternative scenarios of Lorentz-invariance breakdown and could provide and unexpected window on the (quantum) nature of space-time at very short distances.

Giovanni Amelino-Camelia; Tsvi Piran

2000-06-19

286

Demonstration of a Quantile System for Compression of Data from Deep Space Probes  

Microsoft Academic Search

This paper describes the theory and design of an advanced engineering prototype of a quantile system of data compression for space telemetry. The basic idea is to transmit a few quantiles (or percentage points, as they are sometimes called) of a histogram of experimental values formed aboard a spacecraft. Only these quantiles are transmitted to Earth, and yet a large

Tage O. Anderson; Isidore Eisenberger; Warren A. Lushbaugh; Edward C. Posner

1967-01-01

287

Proposal for a Fabry-Perot coupled modular monochromator suitable for rocket payloads or space probes  

Microsoft Academic Search

The tendency of optimizing the weight of spectroscopic space experiments has resulted in the design of a multiple modular spectrometer which is superior to a single big one. The modular monochromator presented here can record a spectrum from 1050 to 8000 Å with 20 to 70 Å resolution. A Fabry-Pérot plate gives access to higher resolution when needed. An advanced

M. Henrist; R. Duysinx; A. Monfils

1974-01-01

288

Probing the Validity of Intelligence Tests for Preschool Children: A Smallest Space Analysis  

Microsoft Academic Search

This study investigates the intra- and inter-test associations between subtest scores on two preschool intelligence measures using Guttman's smallest space analysis (SSA). A sample of 168 Israeli preschoolers from both upper- and lower-class background from nine different kindergartens were tested under controlled conditions on two intelligence test batteries, purporting to assess similar abilities. Notwithstanding the fact that group means on

Moshe Zeidner; Dina Feitelson

1989-01-01

289

Heat stress: a major contributor to poor animal welfare associated with long-haul live export voyages.  

PubMed

Recent investigations by the Australian Department of Agriculture, Fisheries and Forestry into high mortalities on live export voyages from Australia to the Middle East during the Northern hemisphere summer suggest that animal welfare may be compromised by heat stress. The live export industry has generated a computer model that aims to assess the risk of heat stress and to contain mortality levels on live export ships below certain arbitrary limits. Although the model must be complied with under Australian law, it is not currently available for independent scientific scrutiny, and there is concern that model and the mandated space allowances are inadequate. This review appraises the relevant literature on heat stress in sheep and cattle, including laboratory studies aimed at mimicking the ambient temperatures and humidity levels likely to be encountered on live export voyages. Animal welfare is likely to be very poor as a result of heat stress in some shipments. PMID:24157340

Caulfield, Malcolm P; Cambridge, Heather; Foster, Susan F; McGreevy, Paul D

2014-02-01

290

Participatory sensing in public spaces: activating urban surfaces with sensor probes  

Microsoft Academic Search

Recent convergence between low-cost technology, artform and political discourse presents a new design space for enabling public participation and expression. We explore non-experts' use of place-based, modular sensors to activate, author and provoke urban landscapes. Our work with communities of bicyclists, students, parents, and homeless people suggests design opportunities for merging grassroots data collection with public expressions and activism. Members

Stacey Kuznetsov; Eric Paulos

2010-01-01

291

A Tracking Polarimeter for Measuring Solar and Ionospheric Faraday Rotation of Signals from Deep Space Probes  

Microsoft Academic Search

A tracking polarimeter implemented on the 64-m National Aeronautics and Space Administration\\/Jet Propulsion Laboratories (NASA\\/JPL) paraboloid antenna at Goldstone, Calif., is described. Its performance is analyzed and compared with measurements. The system was developed to measure Faraday rotation in the solar corona of the telemetry carrier from the Pioneer VI spacecraft as it was occulted by the sun. It also

John E. Ohlson; Gerald S. Levy; Charles T. Stelzried

1974-01-01

292

Apsis:. AN Artificial Planetary System in Space to Probe Extra-Dimensional Gravity and MOND  

Microsoft Academic Search

A proposal is made to test Newton's inverse-square law using the perihelion shift of test masses (planets) in free fall within a spacecraft located at the Earth-Sun L2 point. Such an artificial planetary system in space (APSIS) will operate in a drag-free environment with controlled experimental conditions and minimal interference from terrestrial sources of contamination. We demonstrate that such a

Varun Sahni; Yuri Shtanov

2008-01-01

293

Probing the Allende meteorite with a miniature laser-ablation mass analyser for space application  

NASA Astrophysics Data System (ADS)

We measured the elemental composition on a sample of Allende meteorite with a miniature laser ablation mass spectrometer. This laser mass spectrometer (LMS) has been designed and built at the University of Bern in the Department of Space Research and Planetary Sciences with the objective of using such an instrument on a space mission. Utilising the meteorite Allende as the test sample in this study, it is demonstrated that the instrument allows the in situ determination of the elemental composition and thus mineralogy and petrology of untreated rocky samples, particularly on planetary surfaces. In total, 138 measurements of elemental compositions have been carried out on an Allende sample. The mass spectrometric data are evaluated and correlated with an optical image. It is demonstrated that by illustrating the measured elements in the form of mineralogical maps, LMS can serve as an element imaging instrument with a very high spatial resolution of ?m scale. The detailed analysis also includes a mineralogical evaluation and an investigation of the volatile element content of Allende. All findings are in good agreement with published data and underline the high sensitivity, accuracy and capability of LMS as a mass analyser for space exploration.

Neuland, M. B.; Meyer, S.; Mezger, K.; Riedo, A.; Tulej, M.; Wurz, P.

2014-10-01

294

The Voyages of Columbus: A Turning Point in World History.  

ERIC Educational Resources Information Center

The far-reaching and transforming interactions of the Old World and the New are known today as "the Columbian Exchange." Part 1 of this booklet is an introduction by John J. Patrick dealing with teaching about the voyages of Christopher Columbus. Part 2, "Columbus and Ecological Imperialism," by Alfred W. Crosby, provides an ecological perspective…

Crosby, Alfred W.; Nader, Helen

295

Voyages of Discovery: Experiencing the Emotion of History  

ERIC Educational Resources Information Center

Guiding students through a dramatic exploration of an historical event can elicit strong emotional reactions that can deepen student understanding and interest in the subject matter. This article describes an integrated third grade lesson plan that focuses on Henry Hudson's voyages in the early 1600s. The students take on the roles of Hudson's…

Kelin, Daniel A., II

2005-01-01

296

Uranus and Neptune data analysis for Voyager 1 and 2  

Microsoft Academic Search

With the successful completion of the Neptune and Triton encounters in 1989, we have focussed on a variety of aspects of the atmospheres of those bodies. At the same time, we have pursued comparative studies of the four outer planets visited by Voyager. Our program of FUV and EUV astrophysical observations has remained active as well. We have used emission

A. L. Broadfoot

1991-01-01

297

Planetary radio astronomy observations from Voyager 1 near Saturn  

Microsoft Academic Search

The Voyager 1 planetary radio astronomy experiment detected two distinct kinds of radio emissions from Saturn. The first, Saturn kilometric radiation, is strongly polarized, bursty, tightly correlated with Saturn's rotation, and exhibits complex dynamic spectral features somewhat reminiscent of those in Jupiter's radio emission. It appears in radio frequencies below about 1.2 megahertz. The second kind of radio emission, Saturn

J. W. Warwick; J. B. Pearce; D. R. Evans; T. D. Carr; J. J. Schauble; J. K. Alexander; M. L. Kaiser; M. D. Desch; M. Pedersen; A. Lecacheux; G. Daigne; A. Boischot; C. H. Barrow

1981-01-01

298

Magnetic field studies by Voyager 2 - Preliminary results at Saturn  

NASA Technical Reports Server (NTRS)

Results of Voyager 2 studies of the magnetosphere and planetary magnetic field of Saturn are presented. Magnetometer studies have confirmed the results obtained by Voyager 1, indicating the magnetic field to be that of a centered dipole of moment 0.21 gauss Saturn radii-cubed, tilted approximately 0.8 deg from the rotation axis and a maximum measured field intensity of 1187 nT at latitude 17.3 deg N just before periapsis. Voyager 2 observed multiple bow shock and magnetopause crossings during its inbound and outbound trajectories, which were complementary to those of Voyager 1, including magnetopause crossing at 18.5 Saturn radii on the inbound trajectory, and at 48.4-50.9 Saturn radii outbound indicative of magnetospheric expansion due to changing solar wind conditions. Throughout the outbound passage, the magnetospheric field was observed to be relatively steady and smooth, with no evidence for any azimuthal asymmetry or magnetic anomaly. Results thus are incapable of accounting for the observed periodic modulation of the Saturnian kilometric radio emissions.

Ness, N. F.; Acuna, M. H.; Behannon, K. W.; Burlaga, L. F.; Connerney, J. E. P.; Lepping, R. P.; Neubauer, F. M.

1982-01-01

299

Recent Particle Measurements from Voyagers 1 and 2  

NASA Astrophysics Data System (ADS)

We summarize recent measurements made by the LECP instrument on Voyager 1 near its crossing of the heliopause and entry into the interstellar medium on or about day 238 of 2012 at 121.6 AU, and on Voyager 2 mainly during the period 2012-2014.4 characterized by large variations in the intensities and angular distributions of low-energy heliosheath ions and the reappearance of low-energy heliosheath electrons. Results from Voyager 1 not previously published include the energy dependence of ion intensity decreases prior to the heliopause crossing and a quantitative measure of the evolution of low-energy heliosheath proton pitch angle distributions that extend across the heliopause. For Voyager 2 we describe the evolution in time and with ion energy of the tangential streaming of ions directed from the nose toward the tail of the heliosheath, summarize the recovery of low-energy heliosheath ion intensities since their decline to minimum levels during 2013.0-3013.3, and discuss the effects of this intensity minimum and subsequent recovery on the ion partial pressure in the heliosheath and on its magnitude relative to that of the thermal plasma and the magnetic field.

Decker, R. B.; Krimigis, S. M.; Roelof, E. C.; Hill, M. E.

2015-01-01

300

Jupiter plasma wave observations: an initial Voyager 1 overview  

Microsoft Academic Search

The Voyager 1 plasma wave instrument detected low-frequency radio emissions, ion acoustic waves, and electron plasma oscillations for a period of months before encountering Jupiter's bow shock. In the outer magnetosphere, measurements of trapped radio waves were used to derive an electron density profile. Near and within the Io plasma torus the instrument detected high-frequency electrostatic waves, strong whistler mode

F. L. Scarf; D. A. Gurnett; W. S. Kurth

1979-01-01

301

Whistlers observed by Voyager 1: Detection of lightning on Jupiter  

Microsoft Academic Search

During the Voyager 1 encounter with Jupiter a number of discrete signals were identified in the wideband plasma wave data with characteristics similar to whistlers generated by lightning. In this paper we show that the calculated whistler-mode travel times from Jupiter to the spacecraft are in good agreement with the measured dispersion characteristics, thereby confirming that the signals are caused

D. A. Gurnett; R. R. Shaw; R. R. Anderson; W. S. Kurth; F.L. Scarf

1979-01-01

302

Overview of the Voyager Ultraviolet Spectrometry Results Through Jupiter Encounter  

Microsoft Academic Search

The Voyager ultraviolet spectrometers (UVS) have been making almost continuous observations, in the 500-A to 1700-A wavelength range, of sources in the solar system and galaxy since launch in 1977. Due to their sensitivity, stability, and dynamic range, the spectrometers have made a remarkable number of discoveries pertaining to the Jupiter system, the interstellar medium, astronomical, and astrophysical sources. The

A. L. Broadfoot; B. R. Sandel; D. E. SHEMANSKY; J. C. McConnell; G. R. Smith; J. B. Holberg; S. K. Atreya; T. M. Donahue; D. F. Strobel; J. L. Bertaux

1981-01-01

303

The Jupiter system through the eyes of Voyager 1  

Microsoft Academic Search

The cameras aboard Voyager 1 have provided a closeup view of the Jupiter system, revealing heretofore unknown characteristics and phenomena associated with the planet's atmosphere and the surfaces of its five major satellites. On Jupiter itself, atmospheric motions - the interaction of cloud systems - display complex vorticity. On its dark side, lightening and auroras are observed. A ring was

B. A. Smith; L. A. Soderblom; T. V. Johnson; A. P. Ingersoll; S. A. Collins; E. M. Shoemaker; G. E. Hunt; H. Masursky; M. H. Carr; M. E. Davies; A. F. Cook; J. M. Boyce; T. Owen; G. E. Danielson; C. Sagan; R. F. Beebe; J. Veverka; J. F. McCauley; R. G. Strom; D. Morrison; G. A. Briggs; V. E. Suomi

1979-01-01

304

Voyager 1 planetary radio astronomy observations near Jupiter  

Microsoft Academic Search

Results are reported from the first low frequency radio receiver to be transported into the Jupiter magnetosphere. Dramatic new information was obtained both because Voyager was near or in Jupiter's radio emission sources and also because it was outside the relatively dense solar wind plasma of the inner solar system. Extensive radio arcs, from above 30 MHz to about 1

J. W. Warwick; J. B. Pearce; A. C. Riddle; J. K. Alexander; M. D. Desch; M. L. Kaiser; J. R. Thieman; T. B. Carr; S. Gulkis; A. Boischot; C. C. Harvey; B. M. Pedersen

1979-01-01

305

Voyager Interactive Web Interface to EarthScope  

Microsoft Academic Search

Visualization of data is essential in helping scientists and students develop a conceptual understanding of relationships among many complex types of data and keep track of large amounts of information. Developed initially by UNAVCO for study of global-scale geodynamic processes, the Voyager map visualization tools have evolved into interactive, web-based map utilities that can make scientific results accessible to a

S. C. Eriksson; C. M. Meertens; L. Estey; M. Weingroff; M. W. Hamburger; W. E. Holt; G. A. Richard

2004-01-01

306

Uranus satellites - Hapke parameters from Voyager disk-integrated photometry  

Microsoft Academic Search

An attempt is presently made to obtain improved determinations of the geometric albedos and phase integrals of Miranda, Ariel, Umbriel, Titania, and Oberon, by fitting Hapke's (1981, 1984, 1986) photometric theory to Voyager whole-disk observations of these satellites. It is analytically established that while Umbriel, Titania and Oberon have large-scale roughness comparable to that of the earth's moon, Ariel is

P. Helfenstein; J. Ververka; P. C. Thomas

1988-01-01

307

Voyager measurement of the rotation period of Saturn's magnetic field  

Microsoft Academic Search

We determine Saturn's radio rotation period using measurements made by the Planetary Radio Astronomy experiment onboard the Voyager spacecraft. The sidereal period deduced is 10 hr 39 min 24 sec +- 7 sec. The radio rotation period is presumably that of the planet's magnetic field. We propose a provisional Saturn longitude convention, and we provide equations to compute a longitude

M. D. Desch; M. L. Kaiser

1981-01-01

308

Plasma observations near Saturn - Initial results from Voyager 1  

Microsoft Academic Search

The Voyager 1 encounter with Saturn and its satellites yielded extensive measurements of magnetospheric low-energy plasma electrons and positive ions, both heavy and light, probably of hydrogen and nitrogen or oxygen. At radial distances between 15 and 7 Saturn radii on the inbound trajectory, the plasma appears to corotate with a velocity within 20% of that theoretically expected for rigid

H. S. Bridge; J. W. Belcher; A. J. Lazarus; S. Olbert; J. D. Sullivan; F. Bagenal; P. R. Gazis; R. E. Hartle; K. W. Ogilvie; J. D. Scudder; E. C. Sittler; A. Eviatar; G. L. Siscoe; C. K. Goertz; V. M. Vasyliunas

1981-01-01

309

Voyager 2 in the Uranian system - Imaging science results  

Microsoft Academic Search

Details of the characteristics of the Uranian atmosphere and the surface features and projected formation processes of the Uranian moons are surveyed on the basis of 7000 images obtained by Voyager 2. Brightness distribution curves are provided for the CH4 Uranian atmosphere, and various anomalies, e.g., banding, that are apparent are discussed. Attention is given to the detectable cloud structure,

B. A. Smith; L. A. Soderblom; R. Beebe; D. Bliss; R. H. Brown; S. A. Collins; J. M. Boyce; G. A. Briggs; A. Brahic; J. N. Cuzzi; D. Morrison; G. E. DANIELSON; M. E. DAVIES; T. E. DOWLING; D. GODFREY; C. J. HANSEN; C. HARRIS; G. E. HUNT; A. P. INGERSOLL; T. V. JOHNSON; R. J. KRAUSS; H. MASURSKY; T. OWEN; J. B. PLESCIA; J. B. POLLACK; C. C. PORCO; K. RAGES; C. SAGAN; E. M. SHOEMAKER; L. A. SROMOVSKY; C. STOKER; R. G. STROM; V. E. SUOMI; S. P. SYNNOTT; R. J. TERRILE; P. THOMAS; W. R. THOMPSON; J. VEVERKA

1986-01-01

310

Encounter with Saturn - Voyager 1 imaging science results  

Microsoft Academic Search

As Voyager 1 flew through the Saturn system it returned photographs revealing many new and surprising characteristics of this complicated community of bodies. Saturn's atmosphere has numerous, low-contrast, discrete cloud features and a pattern of circulation significantly different from that of Jupiter. Titan is shrouded in a haze layer that varies in thickness and appearance. Among the icy satellites there

B. A. Smith; L. Soderblom; R. F. Beebe; J. M. Boyce; G. Briggs; A. Bunker; S. A. Collins; C. J. HANSEN; T. V. Johnson; J. L. Mitchell; R. J. Terrile; M. H. Carr; A. F. Cook; J. N. Cuzzi; J. B. Pollack; G. E. Danielson; A. P. Ingersoll; M. E. Davies; G. E. Hunt; H. Masursky; E. M. Shoemaker; D. Morrison; T. Owen; C. Sagan; J. Veverka; R. Strom; V. E. Suomi

1981-01-01

311

Extreme ultraviolet observations from Voyager 2 encounter with Jupiter  

Microsoft Academic Search

The extensive Voyager 2 EUV spectral observations of the Jovian planetary system have produced a number of significant results. The positions of the auroral zones have been defined with the aid of support imaging to the extent that the aurora is now known to correspond to the location of the planetary magnetic field lines intersecting the Io plasma torus. The

B. R. Sandel; D. E. Shemansky; A. L. Broadfoot; J. L. Bertaux; J. E. Blamont; M. J. S. Belton; J. M. Ajello; J. B. Holberg; S. K. Atreya; T. M. Donahue

1979-01-01

312

Voyager 1 and 2 Atlas of Six Saturnian Satellites  

NASA Technical Reports Server (NTRS)

Maps, compiled with data gathered primarily by Voyager 1 and 2 spacecraft, are presented which show the diversity among six of the Saturnian moons. Mimas and Enceladus are mapped in detail. Prelimary maps are given for the other four satellites. Diameter, density, albedo, and distance from mother planet, among much more data, is given for each moon.

Batson, R. M.

1984-01-01

313

Voyager radio science observations of Neptune and triton  

Microsoft Academic Search

The Voyager 2 encounter with the Neptune system included radio science investigations of the masses and densities of Neptune and Triton, the low-order gravitational harmonics of Neptune, the vertical structures of the atmospheres and ionospheres of Neptune and Triton, the composition of the atmosphere of Neptune, and characteristics of ring material. Demanding experimental requirements were met successfully, and study of

G. L. Tyler; V. R. Eshleman; D. L. Gresh; E. M. Gurrola; D. P. Hinson; E. A. Marouf; P. A. Rosen; R. A. Simpson; D. N. Sweetnam; J. D. Anderson; S. E. Borutzki; J. K. Campbell; E. R. Kursinski; G. S. Levy; G. F. Lindal; J. R. Lyons; G. E. Wood; N. Kawashima

1989-01-01

314

Probing space charge and resolving overlimiting current mechanisms at the micro-nanochannel interface  

E-print Network

We present experimental results demonstrating that a primary mechanism for the over-limiting conductance in micro-nanochannel devices is the structure of the extended space charge developing at the depleted interface under high currents. This is correlated with a distinctive maximum in the differential dc resistance. At high voltage, a local minimum is observed in some cases. Based on numerical simulations, this minimum appears to result from surface conduction. Lastly, anomalously sharp resistance minima are observed in devices with shorter nanochannels. These results indicate electroconvective instability plays a minimal role in driving the over-limiting current in these devices.

Schiffbauer, Jarrod; Liel, Uri; Park, Sinwook; Yossifon, Gilad

2014-01-01

315

Probing the Depths of Space Weathering: A Cross-sectional View of Lunar Rock 76015  

NASA Technical Reports Server (NTRS)

The term "space weathering" refers to the cumulative effects of several processes operating at the surface of any solar system body not protected by a thick atmosphere. These processes include cosmic and solar ray irradiation, solar wind implantation and sputtering, as well as melting and vaporization due to micrometeorite bombardment. Space weathering discussions have generally centered around soils but exposed rocks will also incur the effects of weathering. Rocks have much longer surface lifetimes than an individual soil grain and thus record a longer history of exposure. By studying the weathering products which have built up on a rock surface, we can gain a deeper perspective on the weathering process and better assess the relative importance of various weathering components. The weathered coating, or patina, of the lunar rock 76015 has been previously studied using SEM and TEM. It is a noritic breccia with both "glazed" (smooth glassy) and "classic" (microcratered and pancake-bearing) patina coatings. Previous TEM work on 76015 relied on ultramicrotomy to prepare cross sections of the patina coating, but these sections were limited by the "chatter" and loss of material in these brittle samples. Here we have used a focused ion beam (FIB) instrument to prepare cross sections in which the delicate stratigraphy of the patina coating is beautifully preserved.

Noble, Sarah K.; Keller, L. P.; Stroud, Rhonda

2007-01-01

316

A new way of probing reaction networks: analyzing multidimensional parameter space.  

PubMed

Technically relevant partial oxidation reactions represent complex reaction networks. Establishing a kinetic model for a system of multiple consecutive and parallel reaction steps is a challenging goal. The synthesis of acrylic acid by oxidation of propane using MoVTeNb mixed oxide as catalyst is such a reaction network. In an on-going study, a 10- fold parallel reactor set-up is used to vary systematically reaction conditions in a broad range over a single, well-defined MoVTeNb oxide. Selectivity and product yield in a multidimensional parameter space can give insight into the reaction network. Apparent activation energies and reaction orders of propane are derived for several conditions. Optimum reaction conditions within the investigated parameter space are specified. The results presented within this contribution contain about 200 data points measured in steady states each corresponding to reaction conditions that differ in temperature, contact time, and propane feed concentration. The fact that this data was collected in less than two months shows clearly the advantage of parallel screening of reaction conditions for mechanistic studies. PMID:22023149

d'Alnoncourt, Raoul Naumann; Kolen'ko, Yury V; Schlogl, Robert; Trunschke, Annette

2012-02-01

317

Emission-Line Galaxies from the Hubble Space Telescope Probing Evolution and Reionization Spectroscopically (PEARS) Grism Survey. I. The South Fields  

Microsoft Academic Search

We present results of a search for emission-line galaxies (ELGs) in the southern fields of the Hubble Space Telescope Probing Evolution And Reionization Spectroscopically (PEARS) grism survey. The PEARS South Fields consist of five Advanced Camera for Surveys pointings (including the Hubble Ultra Deep Field) with the G800L grism for a total of 120 orbits, revealing thousands of faint object

Amber N. Straughn; Norbert Pirzkal; Gerhardt R. Meurer; Seth H. Cohen; Rogier A. Windhorst; Sangeeta Malhotra; James Rhoads; Jonathan P. Gardner; Nimish P. Hathi; Rolf A. Jansen; Norman Grogin; Nino Panagia; Sperello di Serego Alighieri; Caryl Gronwall; Jeremy Walsh; Anna Pasquali; Chun Xu

2009-01-01

318

Comparison of Pioneer 10, Voyager 1, and Voyager 2 Ultraviolet Observations with Anti-solar Lyman-alpha Backscatter Simulations  

NASA Astrophysics Data System (ADS)

Observations made by ultraviolet (UV) detectors on board Pioneer 10, Voyager 1, and Voyager 2 can be used to analyze the distribution of neutral hydrogen throughout the heliosphere, including the interaction regions of the solar wind and local interstellar medium. Previous studies of the long-term trend of decreasing intensity with increasing heliocentric distance established the need for more sophisticated heliospheric models. Here we use state-of-the-art three-dimensional (3D) magnetohydrodynamic (MHD) neutral models to simulate Lyman-alpha backscatter as would be seen by the three spacecrafts, exploiting a new 3D Monte Carlo radiative transfer code under solar minimum conditions. Both observations and simulations of the UV backscatter intensity are normalized for each spacecraft flight path at ~15 AU, and we focus on the slope of decreasing intensity over an increasing heliocentric distance. Comparisons of simulations with Voyager 1 Lyman-alpha data results in a very close match, while the Pioneer 10 comparison is similar due to normalization, but not considered to be in agreement. The deviations may be influenced by a low resolution of photoionization in the 3D MHD-neutral model, a lack of solar cycle activity in our simulations, and possibly issues with instrumental sensitivity. Comparing the slope of Voyager 2 and the simulated intensities yields an almost identical match. Our results predict a large increase in the Lyman-alpha intensity as the hydrogen wall is approached, which would signal an imminent crossing of the heliopause.

Fayock, B.; Zank, G. P.; Heerikhuisen, J.

2013-09-01

319

Recent Observations of Anomalous Cosmic Rays as Voyager 1 Approaches the Heliopause  

NASA Astrophysics Data System (ADS)

The Voyager 1 spacecraft crossed the termination shock of the solar wind on 16 December 2004 at 94 AU from the Sun and is now approaching the heliopause, the final boundary between the heliosphere and interstellar space. Two recent particle intensity events suggest this crossing will be accomplished in a series of steps through a structured boundary region. Beginning 7 May 2012, the >70 MeV counting rate (mainly galactic cosmic ray protons) began increasing over a 30 day period to a level about 10% higher than it had been. At the same time, the intensity of ~7-60 MeV/nuc particles, dominated by anomalous cosmic ray (ACR) H, dropped by about the same percentage, suggesting Voyager 1 had entered a new region with reduced ACR intensity. A second particle intensity event that began on 28 July 2012 was even more dramatic, with larger intensity changes over shorter periods of time. The further increases in the GCR intensities were accompanied by decreases in the intensity of ACRs, and the counting rate of >0.5 MeV particles, dominated by termination shock particles, dropped by a factor of two in less than 18 hours. Significant anisotropies are sometimes observed in the ACRs and termination shock particles, and there are ~6-day periodicities in MeV electron rates. The latest observations will be presented at the meeting. This work was supported by NASA under contract NAS7-03001.

Cummings, A. C.; Stone, E. C.; McDonald, F. B.; Heikkila, B.; Lal, N.; Webber, W. R.

2012-12-01

320

Determination of the position of Jupiter from radio metric tracking of Voyager 1  

NASA Technical Reports Server (NTRS)

The Voyager 1 spacecraft flew by Jupiter on March 5, 1979. Spacecraft navigation was performed with radio tracking data from NASA's Deep Space Network. In the years since then, there has been a great deal of progress in the definition of celestial reference frames and in determining the orbit and orientation of the Earth. Using these improvements, the radio metric range and Doppler data acquired from the Voyager 1 spacecraft near its encounter with Jupiter have been reanalyzed to determine the plane-of-sky position of Jupiter with much greater accuracy than was possible at the time of the encounter. The position of Jupiter at the time of encounter has been determined with an accuracy of 40 nrad in right ascension and 140 nrad in declination with respect to the celestial reference frame defined by the International Earth Rotation Service. This position estimate has been done to improve the ephemeris of Jupiter prior to the upcoming encounter of the Galileo spacecraft with Jupiter.

Folkner, W. M.; Haw, R. J.

1995-01-01

321

Endeavour's Final Voyage - Duration: 9:23.  

NASA Video Gallery

After nearly two decades of achievements in space, Endeavour makes one last reach for the stars on its 25th and final mission, STS-134. This webcast examines the mission to come and explores the st...

322

Tone-Based Command of Deep Space Probes using Ground Antennas  

NASA Technical Reports Server (NTRS)

A document discusses a technique for enabling the reception of spacecraft commands at received signal levels as much as three orders of magnitude below those of current deep space systems. Tone-based commanding deals with the reception of commands that are sent in the form of precise frequency offsets using an open-loop receiver. The key elements of this technique are an ultrastable oscillator and open-loop receiver onboard the spacecraft, both of which are part of the existing New Horizons (Pluto flyby) communications system design. This enables possible flight experimentation for tone-based commanding during the long cruise of the spacecraft to Pluto. In this technique, it is also necessary to accurately remove Doppler shift from the uplink signal presented to the spacecraft. A signal processor in the spacecraft performs a discrete Fourier transform on the received signal to determine the frequency of the received signal. Due to the long-term drift in the oscillators and orbit prediction model, the system is likely to be implemented differentially, where changes in the uplink frequency convey the command information.

Bokulic, Robert S.; Jensen, J. Robert

2008-01-01

323

Gravity field estimation from future space missions - TOPEX/POSEIDON, Gravity Probe B, and ARISTOTELES  

NASA Technical Reports Server (NTRS)

Accurate knowledge of the gravity field is a firm requirement in any study of Planet Earth. Space techniques have so far demonstrated their superiority in the global mapping of the gravity field based on ground tracking and altimeter data mostly. Numerical and analytical simulation studies of the upcoming geophysically relevant missions that will most likely carry GPS receivers, indicate significant improvements in the accuracy as well as the resolution of the gravity field. TOPEX will improve by some two orders of magnitude the long wavelength part (to degree about 20), while GP-B will contribute in the long as well as medium wavelength part of the spectrum (up to degree about 60). The gradiometer measurements on ARISTOTELES will contribute in the medium and short wavelength regions (from degree 30 up); GPS tracking of the spacecraft though will provide additional information for the long wavelength gravity and will help resolve it to accuracies comparable to those obtained from GP-B. With the mean rms coefficient error per degree kept below 10 exp -10, geophysical signals such as the post-glacial rebound, tidal variations, and secular and periodic variations of the zonal field rise above the noise level and become readily observable processes.

Pavlis, Erricos C.

1992-01-01

324

Voyager Saturn encounter attitude and articulation control experience  

NASA Technical Reports Server (NTRS)

The Voyager attitude and articulation control system is designed for a three-axis stabilized spacecraft; it uses a biasable sun sensor and a Canopus Star Tracker (CST) for celestial control, as well as a dry inertial reference unit, comprised of three dual-axis dry gryos, for inertial control. A series of complex maneuvers was required during the first of two Voyager spacecraft encounters with Saturn (November 13, 1980); these maneuvers involved rotating the spacecraft simultaneously about two or three axes while maintaining accurate pointing of the scan platform. Titan and Saturn earth occulation experiments and a ring scattering experiment are described. Target motion compensation and the effects of celestial sensor interference are also considered. Failure of the CST, which required an extensive reevaluation of the star reference and attitude control mode strategy, is discussed. Results analyzed thus far show that the system performed with high accuracy, gathering data deeper into Saturn's atmosphere than on any previous planetary encounter.

Carlisle, G.; Hill, M.

1981-01-01

325

Plasma waves near Saturn: Initial results from Voyager 1  

NASA Technical Reports Server (NTRS)

The Voyager 1 encounter with Saturn provided the first opportunity to investigate plasma wave interactions in the magnetosphere of Saturn. An overview of the principal results from the Voyager 1 plasma wave instrument is presented starting with the initial detection of Saturn and ending about four weeks after closest approach. A survey plot of the electric field intensities detected during the Saturn encounter is shown starting shortly before the inbound shock crossing and ending shortly after the outbound magnetopause crossing. Many intense waves were observed in the vicinity of Saturn. To provide a framework for presenting the observations, the results are discussed more or less according to the sequence in which the data were obtained.

Gurnett, D. A.; Kurth, W. S.; Scarf, F. L.

1981-01-01

326

The Voyage of the James Caird by Ernest Shackleton  

NSDL National Science Digital Library

This is an excerpt from Ernest Shackleton's book, "The Voyage of the James Caird". It provides a firsthand report of Ernest Shackleton's epic 800-mile ocean crossing in a twenty-two foot lifeboat, the "James Caird", to find help after his specially constructed ship, the "Endurance", was trapped and crushed by the Antarctic pack ice. The material includes biographic information about Shackleton, who made four voyages to Antarctica and was knighted for one of his expeditions, his account of the rescue journey he embarked on with five men to obtain help for his stranded crew, and his report of sailing aboard the Chilean steamer Yelcho to rescue the rest of his crew on Elephant Island after 105 days.

327

The galilean satellites and Jupiter: Voyager 2 imaging science results  

USGS Publications Warehouse

Voyager 2, during its encounter with the Jupiter system, provided images that both complement and supplement in important ways the Voyager 1 images. While many changes have been observed in Jupiter's visual appearance, few, yet significant, changes have been detected in the principal atmospheric currents. Jupiter's ring system is strongly forward scattering at visual wavelengths and consists of a narrow annulus of highest particle density, within which is a broader region in which the density is lower. On Io, changes are observed in eruptive activity, plume structure, and surface albedo patterns. Europa's surface retains little or no record of intense meteorite bombardment, but does reveal a complex and, as yet, little-understood system of overlapping bright and dark linear features. Ganymede is found to have at least one unit of heavily cratered terrain on a surface that otherwise suggests widespread tectonism. Except for two large ringed basins, Callisto's entire surface is heavily cratered. Copyright ?? 1979 AAAS.

Smith, B.A.; Soderblom, L.A.; Beebe, R.; Boyce, J.; Briggs, G.; Carr, M.; Collins, S.A.; Cook, A.F., II; Danielson, G.E.; Davies, M.E.; Hunt, G.E.; Ingersoll, A.; Johnson, T.V.; Masursky, H.; McCauley, J.; Morrison, D.; Owen, T.; Sagan, C.; Shoemaker, E.M.; Strom, R.; Suomi, V.E.; Veverka, J.

1979-01-01

328

The European Voyages of Exploration: The Fifteenth and Sixteenth Centuries  

NSDL National Science Digital Library

This richly illustrated (yet quickly loading) tutorial from the Applied History Research Group at the University of Calgary guides users through the European voyages of exploration and conquest in the fifteenth and sixteenth centuries. Focusing on Spain and Portugal, the site explores the economic, political, and cultural factors that sustained and advanced exploration. Users will find brief histories of the two kingdoms and overviews of their voyages to the Atlantic, Africa, Asia, the Caribbean, and the Americas. The tutorial includes numerous maps, in addition to discussions of issues such as cartography, navigation, warfare, religion, slavery, and communication, in the Knowledge & Power section. Secondary School or freshman-level university instructors teaching courses on exploration or Early Modern Europe may find this a useful resource for students.

Chastko, Paul.

329

Formation of relief on Europa's surface and analysis of a melting probe movement through the ice  

NASA Astrophysics Data System (ADS)

These days, studies of planetary bodies' are of great interest. And of special interest are the icy moons of the giant planets like Jupiter and Saturn. Analysis of 'Voyager 1', 'Voyager 2', 'Galileo' and 'Cassini' spacecraft data showed that icy covers were observed on Jupiter's moons Ganymede, Europa and Calisto, and Saturn's moons Titan and Enceladus. Of particular interest is the relatively smooth surface of Europa. The entire surface is covered by a system of bands, valleys, and ridges. These structures are explained by the mobility of surface ice, and the impact of stress and large-scale tectonic processes. Also conditions on these moons allow speculation about possible life, considering these moons from an astrobiological point of view. To study the planetary icy body in future space missions, one of the problems to solve is the problem of design of a special device capable of penetrating through the ice, as well as the choice of the landing site of this probe. To select a possible landing site, analysis of Europa's surface relief formation is studied. This analysis showed that compression, extention, shearing, and bending can influence some arbitrarily separated section of Europe's icy surface. The computer simulation with the finite element method (FEM) was performed to see what types of defects could arise from such effects. The analysis showed that fractures and cracks could have various forms depending on the stress-strained state arising in their vicinity. Also the problem of a melting probe's movement through the ice is considered: How the probe will move in low gravity and low atmospheric pressure; whether the hole formed in the ice will be closed when the probe penetrates far enough or not; what is the influence of the probe's characteristics on the melting process; what would be the order of magnitude of the penetration velocity. This study explores the technique based on elasto-plastic theory and so-called 'solid water' theory to estimate the melting velocity and to study the melting process. Based on this technique, several cases of melting probe motion are considered, the velocity of the melting probe is estimated, the influence of different factors are studied and discussed, and an easy way to optimize the parameters of the probe is proposed.

Erokhina, O. S.; Chumachenko, E. N.; Dunham, D. W.; Aksenov, S. A.; Logashina, I. V.

2013-12-01

330

Evidence from Voyager II photometry for early resurfacing of Umbriel  

NASA Astrophysics Data System (ADS)

New Voyager II albedo maps of Umbriel are presented which reveal that its surface is subdivided into low-contrast, crudely polygonal areas ranging in size from tens to hundreds of km. The largest polygons are elongate with systematically trending northeast-southwest boundaries. Some of the polygonal areas form topographic depressions several km in depth. It is suggested that this newly discovered global albedo pattern is a relic of the early tectonic disruption of Umbriel's surface.

Helfenstein, P.; Thomas, P. C.; Veverka, J.

1989-03-01

331

Detection of Titan's Ionosphere from Voyager 1 Radio Occultation Observations  

Microsoft Academic Search

Evidence for a marginal detection of the Titan ionosphere has been obtained from a new analysis of the dual-frequency Doppler data recorded during the Voyager 1 occultation in 1980. The original report by Lindal et al. (1983, Icarus 53, 348-363) gave only upper bounds on the peak electron density of 3000 cm^-3 during ingress (evening terminator) and 5000 cm^-3 during

M. K. Bird; R. Dutta-Roy; S. W. Asmar; T. A. Rebold

1997-01-01

332

Mapping the Galilean satellites of Jupiter with Voyager data.  

USGS Publications Warehouse

The four Galilean satellites of Jupiter are being mapped using image data from the Voyager 1 and 2 spacecraft. The maps are published at several scales and in several versions. Preliminary maps at 1:25,000,000-required for mission planning and preliminary science reports-were compiled within three weeks of data acquisition and have been published. Later maps incorporate Rand Corporation photogrammetric triangulations. - from Authors

Batson, R.M.

1980-01-01

333

Extreme ultraviolet observations from Voyager 1 encounter with Jupiter  

Microsoft Academic Search

Observations of the optical extreme ultraviolet spectrum of the Jupiter planetary system during the Voyager 1 encounter have revealed previously undetected physical processes of significant proportions. Bright emission lines of S(+2), S(+3), O(+2) indicating an electron temperature of 100,000 K have been identified in preliminary analyses of the Io plasma torus spectrum. Strong auroral atomic and molecular hydrogen emissions have

A. L. Broadfoot; M. J. Belton; P. Z. Takacs; B. R. Sandel; D. E. Shemansky; J. B. Holberg; J. M. Ajello; H. W. Moos; S. K. Atreya; T. M. Donahue; J. L. Bertaux; J. E. Blamont; D. F. Strobel; J. C. McConnell; R. Goody; A. Dalgarno; M. B. McElroy

1979-01-01

334

The helium abundance of Uranus from Voyager measurements  

Microsoft Academic Search

Voyager radio-occultation and IR spectroscopy measurements are combined to infer an He mole fraction in the upper troposphere of Uranus of 0.152 + or - 0.033; the corresponding mass fraction is Y = 0.262 + or - 0.048. This value is in agreement with recent estimates of the solar He abundance, suggesting that He differentiation has not occurred on Uranus.

B. Conrath; R. Hanel; D. Gautier; A. Marten; G. Lindal

1987-01-01

335

Extreme and far ultraviolet astronomy from Voyagers 1 and 2  

NASA Technical Reports Server (NTRS)

The instrumental characteristics, observational capabilities and scientific results of the Voyager 1 and 2 ultraviolet spectrometers are reviewed. These instruments provide current and ongoing access to low resolution spectra for a wide variety of astronomical sources in the 500 to 1700 A band. Observations of the brightest OB stars and hot subluminous stars as faint as V = 15 mag, are possible. In the EUV, at wavelengths shortward of 900 A, several new sources have been detected and a host of potential sources ruled out. In the far UV, particularly at wavelengths between 900 and 1200 A, Voyager is capable of observing a wide range of stellar and non-stellar sources. Such observations can often provide a valuable complement to IUE and other data sets at longer wavelengths. The Voyager spectrometers have proved remarkably stable photon counting instruments, capable of extremely long integration times. The long integration times, relatively large field of view, and location in the outer solar system also provide an ideal platform for observations of sources of faint diffuse emission, such as nebulae and the general sky background.

Holberg, J. B.

1990-01-01

336

Abundances of Jupiter's Trace Hydrocarbons from Voyager and Cassini  

NASA Technical Reports Server (NTRS)

The flybys of Jupiter by the Voyager spacecraft in 1979, and over two decades later by Cassini in 2000, have provided us with unique datasets from two different epochs, allowing the investigation of seasonal change in the atmosphere. In this paper we model zonal averages of thermal infrared spectra from the two instruments, Voyager 1 IRIS and Cassini CIRS, to retrieve the vertical and meridional profiles of temperature, and the abundances of the two minor hydrocarbons, acetylene (C2H2) and ethane (C2H6). The spatial variation of these gases is controlled by both chemistry and dynamics, and therefore their observed distribution gives us an insight into both processes, We find that the two gases paint quite different pictures of seasonal change. Whilst the 2-D cross-section of C2H6 abundance is slightly increased and more symmetric in 2000 (northern summer solstice) compared to 1979 (northern fall equinox), the major trend of equator to pole increase remains. For C2H2 on tile other hand, the Voyager epoch exhibits almost no latitudinal variation, whilst the Cassini era shows a marked decrease polewards in both hemispheres. At the present time, these experimental findings are in advance of interpretation, as there are no published models of 2-D Jovian seasonal chemical variation available for comparison.

Nixon, C. A.; Achterberg, R. K.; Romani, P. N.; Allen, M.; Zhang, X.; Teanby, N. A.; Irwin, P. G. J.; Flasar, F. M.

2010-01-01

337

Plasma observations near Saturn - Initial results from Voyager 2  

NASA Technical Reports Server (NTRS)

Results of plasma measurements made by Voyager 2 in the vicinity of Saturn are discussed and compared with those made by Pioneer 11 and Voyager 1 in a more limited range of latitudes. The initial bow shock crossing on the inbound trajectory closely agreed with the shock position inferred from the external ram pressure in the solar wind, although boundaries on the outbound pass were much further out than expected. Magnetospheric plasma observations reveal the presence of (1) shocked solar wind plasma in the magnetosheath between 30 and 22 Saturn radii; (2) a variable density region between 17 Saturn radii and the magnetopause; (3) an extended thick plasma sheet between 17 and 7 Saturn radii; and (4) an inner plasma torus probably originating from local sources. The ratio of heavy to light ions was observed to vary with distance to the equatorial plane in the dayside magnetosphere, with the heavy ions, probably O(+), more closely confined to the equatorial plane. The plasma data also account for the observed inner boundary of the neutral hydrogen torus discovered by Voyager 1.

Bridge, H. S.; Bagenal, F.; Belcher, J. W.; Lazarus, A. J.; Mcnutt, R. L.; Sullivan, J. D.; Gazis, P. R.; Hartle, R. E.; Ogilvie, K. W.; Scudder, J. D.

1982-01-01

338

Changes on Io between Voyager 1 and Galileo's second orbit around an unnamed vent North of  

NASA Technical Reports Server (NTRS)

Detail of changes around a probable vent about 650 kilometers north of Prometheus on Jupiter's moon Io as seen in images obtained by the Voyager 1 spacecraft in April 1979 (left) and the imaging system aboard NASA's Galileo spacecraft on September 7th, 1996 (right). The re-arranging of dark and light radial surface patterns may be a result of plume fallout. North is to the top of both images which are approximately 400 kilometers square.

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

1996-01-01

339

46 CFR 108.209 - Hospital spaces.  

Code of Federal Regulations, 2012 CFR

...more persons on a voyage of more than three days must have a hospital space. (b) Each hospital space must be suitably separated from other spaces. (c) No hospital space may be used for any other purpose, when used for care of the...

2012-10-01

340

46 CFR 108.209 - Hospital spaces.  

...more persons on a voyage of more than three days must have a hospital space. (b) Each hospital space must be suitably separated from other spaces. (c) No hospital space may be used for any other purpose, when used for care of the...

2014-10-01

341

46 CFR 108.209 - Hospital spaces.  

Code of Federal Regulations, 2013 CFR

...more persons on a voyage of more than three days must have a hospital space. (b) Each hospital space must be suitably separated from other spaces. (c) No hospital space may be used for any other purpose, when used for care of the...

2013-10-01

342

46 CFR 108.209 - Hospital spaces.  

Code of Federal Regulations, 2011 CFR

...more persons on a voyage of more than three days must have a hospital space. (b) Each hospital space must be suitably separated from other spaces. (c) No hospital space may be used for any other purpose, when used for care of the...

2011-10-01

343

Voyager electronic parts radiation program. Volume 2: Test requirements and procedures  

NASA Technical Reports Server (NTRS)

Documents are presented outlining the conditions and requirements of the test program. The Appendixes are as follows: appendix A -- Electron Simulation Radiation Test Specification for Voyager Electronic Parts and Devices, appendix B -- Electronic Piece-Part Testing Program for Voyager, appendix C -- Test Procedure for Radiation Screening of Voyager Piece Parts, appendix D -- Boeing In Situ Test Fixture, and appendix E -- Irradiate - Anneal (IRAN) Screening Documents.

Stanley, A. G.; Martin, K. E.; Price, W. E.

1978-01-01

344

Planetary and Space Science 56 (2008) 586600 Reconstruction of the trajectory of the Huygens probe using the  

E-print Network

December 2007 Abstract The Huygens probe returned scientific measurements from the atmosphere and surface of Titan on 14 January 2005. Knowledge of the trajectory of Huygens is necessary for scientific analysis the probe's attitude during hypersonic entry, were significantly less accurate and limited by transverse

Withers, Paul

345

Energy spectra of high energy electrons and hard X-rays as observed onboard the space probe Venera 11 during the solar flare event of April 13 1979  

Microsoft Academic Search

Simultaneous observations of high-energy electron spectra and hard-X-ray spectra from the solar flare of April 13, 1979 which were obtained by the Venera 11 space probe en route to Venus are presented. Electron spectra were measured in the range 60 to 2100 keV with a time resolution of 20 minutes and compared with hard X-ray spectra measured in the range

E. I. Daibog; E. A. Devicheva; S. V. Golenetskij; Yu. A. Gur'yan; V. G. Stopovskii; S. V. Golenetskii; Iu. A. Gurian; V. G. Stolpovskii; V. G. Stolpovskij; A. Varga

1981-01-01

346

Designing the United States' initial 'Deep-Space Networks' - Choices for the Pioneer lunar-probe attempts of 1958-59  

NASA Technical Reports Server (NTRS)

The paper describes two separate networks for ground-support stations, designed, respectively, by the Space Technology Laboratories (STL) and the Jet Propulsion Laboratory (JPL), to support the series of early Pioneer lunar-probe attempts. Particular attention is given to the characteristics of an ideal ground-support station and to the criteria used for the selection of the antenna, the antenna station site, and the frequency for the STL and JPL networks.

Waff, Craig B.

1993-01-01

347

Preliminary results of a gamma-ray burst study in the KONUS experiment on the Venera-11 and Venera-12 space probes  

Microsoft Academic Search

Twenty-one gamma-ray bursts and 68 solar flares in the hard X-ray range were detected on Venera-11 and Venera-12 space probes during the initial 50-day observation period. Major characteristics of the equipment used and preliminary data on the temporal structure and energy spectra of the gamma-ray bursts are considered. The pattern of gamma-ray burst frequency distribution vs. intensity, N(S), is established.

Y. P. Mazets; S. V. Golentskiy; V. N. Ilinskiy; V. N. Panov; R. L. Aptekar; Y. A. Guryan; I. A. Sokolov; Z. Y. Sokolova; T. V. Kharitonova

1979-01-01

348

Exploring the brain, looking for thoughts: on Asimov's second Fantastic Voyage.  

PubMed

The aim of this paper is to investigate various concerns which appear in Isaac Asimov's Fantastic Voyage II: Destination Brain. I will disregard his first voyage inside a human body in Fantastic Voyage I, which the author disavows as not being his own work. In contrast, the second voyage is intricate, suggesting problems drawn from a variety of sources. In a nutshell, Asimov's explorers enter the body of a comatose man in order to read his thoughts. The story can be related both to philosophical thought-experiments, such as those of Gottfried Wilhelm Leibniz and of Herbert Feigl, as well as to personal anxieties peculiar to Asimov. PMID:21936209

Cassou-Noguès, Pierre

2011-01-01

349

Observed Coupling Between the International Space Station PCU Plasma and a FPMU Langmuir Probe Facilitated by the Geomagnetic Field  

NASA Technical Reports Server (NTRS)

Electrical charging of the International Space Station (ISS) is a matter of serious concern resulting from the possibility of vehicle arcing and electrical shock hazard to crew during extravehicular activity (EVA). A Plasma Contactor Unit (PCU) was developed and integrated into ISS in order to control the ISS floating potential, thereby, minimize vehicle charging and associated hazards. One of the principle factors affecting ISS electrical charging is the ionosphere plasma state (i.e., electron temperature and density). To support ISS electrical charging studies a Floating Potential Monitoring Unit (FPMU) is also integrated into ISS in order to measure the ionosphere properties using Langmuir probes (LP). The FPMU was located on the Starboard side of ISS. The PCU is located near the center of ISS with its plasma exhaust pointed to port. From its integration on ISS in 2006 through November of 2009, the FPMU data exhibited nominal characteristics during PCU operation. On November 21, 2009 the FPMU was relocated from the Starboard location to a new Port location. After relocation significant enhanced noise was observed in both the LP current-voltage sweeps and the derived electron temperature data. The enhanced noise only occurred when the PCU was in discharge and at unique and repeatable locations of the ISS orbit. The cause of this enhanced noise was investigated. It was found that there is coupling occurring between the PCU plasma and the FPMU LP. In this paper we shall 1) present the on-orbit data and the presence of enhanced noise, 2) demonstrate that the coupling of the PCU plasma and the FPMU measurements is geomagnetically organized, 3) show that coupling of the PCU plasma and the FPMU is primarily due to and driven by particle-wave interaction and 4) show that the ionosphere conditions are adequate for Alfven waves to be generated by the PCU plasma.

Hartman, William; Koontz, Steven L.

2010-01-01

350

PREFACE: 13th Annual International Astrophysics Conference: Voyager, IBEX, and the Interstellar Medium  

NASA Astrophysics Data System (ADS)

The 13th Annual International Astrophysics Conference was held in scenic Myrtle Beach, South Carolina, USA, during the week of 10-14 March 2014. The meeting drew nearly 80 participants from all over the world, representing a wide range of interests and expertise in the interplanetary medium, the solar wind, observations, and theory. The theme of the meeting was Voyager, IBEX, and the Interstellar Medium. This decade may one day be viewed as the golden age in the exploration of the large-scale heliosphere and the local interstellar medium (LISM). Voyager 1 and 2 and IBEX are yielding remarkable new discoveries about the boundaries of the solar wind - LISM region and the interstellar medium. Hitherto, our basic understanding of the interstellar medium has been provided by telescope observations across multiple wavelengths that are typically integrated over many parsecs. For the first time, with these three spacecraft, we are making detailed measurements of the interstellar plasma, energetic particles (charged and neutral), magnetic field, and plasma waves in situ or with very short integration distances. IBEX provides insight into the global characteristics of the very local interstellar medium and Voyager 1 has just crossed the heliopause and is now in the interstellar medium. Remarkable results can be anticipated as discoveries over the next decade are made and the physics of the interstellar medium unfolds. As described in the papers in this volume, the new observations are already challenging theoretical models. The 13th Annual International Conference focused on the physics of the solar wind - LISM boundaries and the emerging physics of the local interstellar medium. To address this, astrophysicists and space physicists assembled to share their combined expertise to address in a highly interdisciplinary fashion the physics of the interaction between the solar wind and the interstellar medium. We thank Adele Corona and ICNS for her continued excellent organization of the AIAC meetings and her help in providing the logistical support for this volume of papers. I should also like to thank Laxman Adhikari for his help with formatting a number of the submitted manuscripts.

Zank, G. P.

2015-01-01

351

Space Mission to the Moon with a Low Cost Moon Probe Nanosatellite: University Project Feasibility Analysis and Design Concepts  

NASA Astrophysics Data System (ADS)

This paper discusses the possibility of launching a 10 kg nanosatellite moon probe with a joint university effort along with industrial partners for a low cost mission to the moon. It will allow for vital experiments to take place.

Guven, U. G.; Velidi, G. V.; Datta, L. D.

2014-10-01

352

Uranus' southern circulation revealed by Voyager 2: Unique characteristics  

NASA Astrophysics Data System (ADS)

Revised calibration and processing of 1600 images of Uranus by Voyager 2 revealed dozens of discrete features south of -45° latitude, where only a single feature was known from Voyager images and none has been seen since. Tracking of these features over five weeks defined the southern rotational profile of Uranus with high accuracy and no significant gap. The profile has kinks unlike previous profiles and is strongly asymmetric with respect to the northern profile by Sromovsky et al. (Sromovsky, L.A., Fry, P.M., Hammel, H.B., de Pater, I., Rages, K.A. [2012]. Icarus 220, 694-712). The asymmetry is larger than that of all previous data on jovian planets. A spot that included the South Pole off-center rotated with a period of 12.24 h, 2 h outside the range of all previous observations of Uranus. The region between -68° and -59° latitude rotated almost like a solid body, with a shear that was about 30 times smaller than typical shears on Uranus. At lower latitudes, features were sheared into tightly wound spirals as Voyager watched. The zone at -84° latitude was exceptionally bland; reflectivity variations were only 18 ppm, consistent with a signal-to-noise ratio estimated at 55,000. The low noise was achieved by smoothing over dozens of pixels per image and averaging 1600 images. The presented data set in eight filters contains rich information about temporal evolution and spectral characteristics of features on Uranus that will be the basis for further analysis.

Karkoschka, Erich

2015-04-01

353

UVS-Voyager 1 measurements in the outer heliosphere  

NASA Astrophysics Data System (ADS)

The UVS spectrometer on Voyager 1 is still active in 2014. The only line still observed in the spectral range covered by UVS is the HI Lyman alpha transition due to the backscattering of solar photons by H atoms in the outer heliosphere. The background intensity corresponds to a few tens of rayleigh. In 2003, movements of the Voyager 1 scan platforms were stopped and since then the line of sight of UVS has been fixed. It is pointing towards a direction close to the upwind direction. Over the 2003-2010 period, IPH background data have been very constant and followed the variations of the solar illuminating flux at lyman alpha, smoothed by multiple scattering efftects between the sun and the outer heliosphere. After corrrection from solar flux variations, data obtained in this period changed by less than 10% over a distance of more than 20 AU which is difficult to explain with radiative transfer models. However, a change in the radial dependence of the data started in 2011 and lasted until the end of 2013. New measurements in early 2014 show a stabilization and a return to the previous pattern. This needs to be confirmed in the next few months. We will present the UVS-V1 data, and give special attention to possible instrumental effects linked to thermal changes in the Voyager 1 spacecraft as various heaters are switched off. We think that the changes observed since 2011 are not due to instrumental effects. We will also present some ideas that can help us to explain the UVS observations. To do this, it is necessary to modify our current picture of the distribution of hydrogen atoms in the outer heliosphere. These new results have an impact on our understanding of the heliospheric interface.

Quemerais, Eric; Sandel, Bill R.; Bertaux, Jean-Loup; Lallement, Rosine

354

Voyager and the origin of the solar system  

NASA Technical Reports Server (NTRS)

A unified model for the formation of regular satellite systems and the planetary system is outlined. The basis for this modern Laplacian theory is that there existed a large supersonic turbulent stress arising from overshooting convective motions within the three primitive gaseous clouds which formed Jupiter, Saturn, and the Sun. Calculations show that if each cloud possessed the same fraction of supersonic turbulent energy, equal to about 5% of the cloud's gravitational potential energy, then the broad mass distribution and chemistry of all regular satellite and planetary systems can be simultaneously accounted for. Titan is probably a captured moon of Saturn. Several predictions about observations made by Voyager 2 at Saturn are presented.

Prentice, A. J. R.

1981-01-01

355

Post Voyager comparisons of the interiors of Uranus and Neptune  

NASA Technical Reports Server (NTRS)

The recent Voyager flyby of Uranus and Neptune has provided refined values for the gravitational moments and rotation periods of those planets. Using these new parameters, models of the interiors of these planets show that their density distributions are very similar. This lends support to the conjecture that their compositions are similar as well. The models are indeed consistent with such a conjecture. The difference in the internal heat sources of these two planets may be due to the fact that heat transport from the interior of Uranus is inhibited by a statically stable interior.

Podolak, M.; Reynolds, R. T.; Young, R.

1990-01-01

356

Uranus satellites - Hapke parameters from Voyager disk-integrated photometry  

NASA Technical Reports Server (NTRS)

An attempt is presently made to obtain improved determinations of the geometric albedos and phase integrals of Miranda, Ariel, Umbriel, Titania, and Oberon, by fitting Hapke's (1981, 1984, 1986) photometric theory to Voyager whole-disk observations of these satellites. It is analytically established that while Umbriel, Titania and Oberon have large-scale roughness comparable to that of the earth's moon, Ariel is significantly rougher. While the particle single scattering albedo is strikingly different among the satellites, the degrees of regolith particle backscattering are very similar.

Helfenstein, Paul; Veverka, Joseph; Thomas, Peter C.

1988-01-01

357

The Jupiter system through the eyes of Voyager 1  

USGS Publications Warehouse

The cameras aboard Voyager I have provided a closeup view of the Jupiter system, revealing heretofore unknown characteristics and phenomena associated with the planet's atmosphere and the surfaces of its five major satellites. On Jupiter itself, atmospheric motions-the interaction of cloud systems-display complex vorticity. On its dark side, lightning and auroras are observed. A ring was discovered surrounding Jupiter. The satellite surfaces display dramatic differences including extensive active volcanismn on Io, complex tectonism on Ganymnede and possibly Europa, and flattened remnants of enormous impact features on Callisto. Copyright ?? 1979 AAAS.

Smith, B.A.; Soderblom, L.A.; Johnson, T.V.; Ingersoll, A.P.; Collins, S.A.; Shoemaker, E.M.; Hunt, G.E.; Masursky, H.; Carr, M.H.; Davies, M.E.; Cook, A.F., II; Boyce, J.; Danielson, G.E.; Owen, T.; Sagan, C.; Beebe, R.F.; Veverka, J.; Strom, R.G.; McCauley, J.F.; Morrison, D.; Briggs, G.A.; Suomi, V.E.

1979-01-01

358

Plasma observations near Saturn - Initial results from Voyager 1  

NASA Technical Reports Server (NTRS)

The Voyager 1 encounter with Saturn and its satellites yielded extensive measurements of magnetospheric low-energy plasma electrons and positive ions, both heavy and light, probably of hydrogen and nitrogen or oxygen. At radial distances between 15 and 7 Saturn radii on the inbound trajectory, the plasma appears to corotate with a velocity within 20% of that theoretically expected for rigid corotation. The Titan data, taken while the moon was inside the Saturn magnetosphere, shows a clear signature characteristic of the interaction between a subsonic corotating magnetospheric plasma and the atmospheric or ionospheric exosphere of Titan.

Bridge, H. S.; Belcher, J. W.; Lazarus, A. J.; Olbert, S.; Sullivan, J. D.; Bagenal, F.; Gazis, P. R.; Hartle, R. E.; Ogilvie, K. W.; Scudder, J. D.

1981-01-01

359

Voyager photometry of Triton - Haze and surface photometric properties  

NASA Technical Reports Server (NTRS)

The Voyager whole-disk observations of Triton at 0.41, 0.48, and 0.56 micron filter wavelengths are analyzed using a model which combines an improved version of Hapke's photometric equation with a thin atmospheric haze layer in the appropriate spherical geometry. The model is shown to describe accurately the phase curves over a range of phase angles and to agree with disk-resolved brightness scans along the photometric equator and mirror meridian. According to the model, the photometric parameters of Triton's regolith are reasonably typical of icy satellites, except for the extremely high (close to unity) single-scattering albedo.

Hillier, J.; Helfenstein, P.; Verbiscer, A.; Veverka, J.

1991-01-01

360

IUE and Voyager Observations of the Unusual Cataclysmic Variable S193  

Microsoft Academic Search

UV observations of S193 were obtained with Voyager and the IUE satellite during both high and low states of this unusual object. Voyager only detected the source during the high state, where the continuum looks similar to the novalike IX Vela and dwarf novae at outburst. The IUE spectra at the high state show deep absorption lines, but the line

Paula Szkody; Peter Garnavich; Jay Holberg; Andrew Silber; Lora Pastwick

1997-01-01

361

46 CFR 14.201 - Voyages upon which shipping articles are required.  

Code of Federal Regulations, 2013 CFR

... (iii) The West Indies. (2) Of 75 gross tons or more on a voyage between a port of the United States on the Atlantic Ocean and a port of the United States on the Pacific Coast; or (3) Of 50 gross tons or more on a voyage between a...

2013-10-01

362

ICARUS 88, 448-464 (1990) Reanalysis of Voyager 2 UVS Occultations at Uranus: Hydrocarbon  

E-print Network

ICARUS 88, 448-464 (1990) Reanalysis of Voyager 2 UVS Occultations at Uranus: Hydrocarbon Mixing occultation at Uranus has yielded tighter constraints on the structure and composition of the upper equatorial rcxrvcd #12;VOYAGER UVS OCCULTATIONS AT URANUS 449 occultation data at Jupiter and Saturn (Broadfoot et al

Atreya, Sushil

363

Voyager 2's encounter with Neptune answered many questions about the 'blue' planet  

SciTech Connect

Voyager 2 observations of Neptune from August 1989 are examined. Voyager 2 discovered 6 new moons around Neptune and collected information on the shape and composition of Neptune's rings. The spots and clouds detected in the planet's atmosphere are described. Consideration is given to Neptune's magnetic field and auroras.

Tsurutani, B.T. (JPL, Pasadena, CA (USA))

1990-02-01

364

Saturn’s Upper Atmosphere from the Voyager 2 Euv Solar and Stellar Occultations  

Microsoft Academic Search

The temperature and composition of The preliminary estimate of 850 ñ 100 K for the upper atmosphere of Saturn have been inferred the temperature in the upper atmosphere of Saturn from Voyager 2 ultraviolet spectrometer occulta- based on the Voyager I INS solar occultation tion measurements made by observing the sun and (Broadfoot et al., 1981) appears to be too

Gerald R. Smith; D. E. Shemansky; J. B. Holberg; A. L. Broadfoot; B. R. Sandel; John C. McConnell

1983-01-01

365

Abundances of Jupiter's Trace Hydrocarbons from Voyager and Cassini. Data Tables: Voyager IRIS Observations Planetary and Space Science, Forthcoming 2010  

NASA Technical Reports Server (NTRS)

The following six tables give the retrieved temperatures and volume mixing ratios of C2H2 and C2H6 and the formal errors on these results from the retrieval, as described in the manuscript. These are in the form of two-dimensional tables, specified on a latitudinal and vertical grid. The first column is the pressure in bar, and the second column gives the altitude in kilometers calculated from hydrostatic equilibrium, and applies to the equatorial profile only. The top row of the table specifies the planetographic latitude.

Nixon, C. A.; Achterberg, R. K.; Romani, P. N.; Allen, M.; Zhang, X.; Irwin, P. G. J.; Flasar, F. M.

2010-01-01

366

Encounter with Saturn: Voyager 1 imaging science results  

USGS Publications Warehouse

As Voyager 1 flew through the Saturn system it returned photographs revealing many new and surprising characteristics of this complicated community of bodies. Saturn's atmosphere has numerous, low-contrast, discrete cloud features and a pattern of circulation significantly different from that of Jupiter. Titan is shrouded in a haze layer that varies in thickness and appearance. Among the icy satellites there is considerable variety in density, albedo, and surface morphology and substantial evidence for endogenic surface modification. Trends in density and crater characteristics are quite unlike those of the Galilean satellites. Small inner satellites, three of which were discovered in Voyager images, interact gravitationally with one another and with the ring particles in ways not observed elsewhere in the solar system. Saturn's broad A, B, and C rings contain hundreds of "ringlets," and in the densest portion of the B ring there are numerous nonaxisymmetric features. The narrow F ring has three components which, in at least one instance, are kinked and crisscrossed. Two rings are observed beyond the F ring, and material is seen between the C ring and the planet. Copyright ?? 1981 AAAS.

Smith, B.A.; Soderblom, L.; Beebe, R.; Boyce, J.; Briggs, G.; Bunker, A.; Collins, S.A.; Hansen, C.J.; Johnson, T.V.; Mitchell, J.L.; Terrile, R.J.; Carr, M.; Cook, A.F., II; Cuzzi, J.; Pollack, J.B.; Edward, Danielson G.; Ingersoll, A.; Davies, M.E.; Hunt, G.E.; Masursky, H.; Shoemaker, E.; Morrison, D.; Owen, T.; Sagan, C.; Veverka, J.; Strom, R.; Suomi, V.E.

1981-01-01

367

Voyager 2 fine-scale velocity oscillations at 48 AU  

NASA Astrophysics Data System (ADS)

Voyager 2 solar wind speeds show unusual variations beginning on day 40 of 1996. These variations are oscillations of approximately 30 km/s with periods of about two days and are unlike any variations heretofore detected in the outer heliosphere. Several possible sources of this behavior are examined. First, this speed feature may be due to a Kelvin-Helmholtz instability on the boundary between the slow equatorial and fast high-latitude flows, although this instability has not been observed at other radial distances and latitudes. A second possibility is that these waves are due to instabilities associated with interstellar pick-up ions; at the ?48 AU distance where these oscillations are observed, the pick-up pressure far exceeds the pressure of the thermal solar wind proton population. A third possibility is that the waves are an upstream signature of the termination shock, similar to waves observed upstream of planetary bow shocks. Anomalous cosmic ray protons with 100 MeV energies satisfy the necessary cyclotron resonance conditions and carry sufficient energy density to produce the observed waves. This possibility would require magnetic connection to the shock and the presence of streaming anomalous cosmic ray ions. Plasma data alone cannot determine whether the necessary conditions for any of these possibilities exist. Further progress requires collaborative studies using all of the available particle and field data from Voyager 2.

Paularena, K. I.; Belcher, J. W.; Richardson, J. D.; Gordon, G. S., Jr.; Lazarus, A. J.

368

Multifractal Structures Detected by Voyager 1 at the Heliospheric Boundaries  

NASA Astrophysics Data System (ADS)

To better understand the dynamics of turbulent systems, we have proposed a phenomenological model based on a generalized Cantor set with two rescaling and one weight parameters. In this Letter, using recent Voyager 1 magnetic field data, we extend our two-scale multifractal analysis further in the heliosheath beyond the heliospheric termination shock, and even now near the heliopause, when entering the interstellar medium for the first time in human history. We have identified the scaling inertial region for magnetized heliospheric plasma between the termination shock and the heliopause. We also show that the degree of multifractality decreases with the heliocentric distance and is still modulated by the phases of the solar cycle in the entire heliosphere including the heliosheath. Moreover, we observe the change of scaling toward a nonintermittent (nonmultifractal) behavior in the nearby interstellar medium, just beyond the heliopause. We argue that this loss of multifractal behavior could be a signature of the expected crossing of the heliopause by Voyager 2 in the near future. The results obtained demonstrate that our phenomenological multifractal model exhibits some properties of intermittent turbulence in the solar system plasmas, and we hope that it could shed light on universal characteristics of turbulence.

Macek, W. M.; Wawrzaszek, A.; Burlaga, L. F.

2014-10-01

369

Robots Explore the Farthest Reaches of Earth and Space  

NASA Technical Reports Server (NTRS)

"We were the first that ever burst/Into that silent sea," the title character recounts in Samuel Taylor Coleridge s opus Rime of the Ancient Mariner. This famous couplet is equally applicable to undersea exploration today as surface voyages then, and has recently been applied to space travel in the title of a chronicle of the early years of human space flight ("Into That Silent Sea: Trailblazers of the Space Era, 1961-1965"), companion to the +n the Shadow of the Moon book and movie. The parallel is certainly fitting, considering both fields explore unknown, harsh, and tantalizingly inhospitable environments. For starters, exploring the Briny Deep and the Final Frontier requires special vehicles, and the most economical and safest means for each employ remotely operated vehicles (ROVs). ROVs have proven the tool of choice for exploring remote locations, allowing scientists to explore the deepest part of the sea and the furthest reaches of the solar system with the least weight penalty, the most flexibility and specialization of design, and without the need to provide for sustaining human life, or the risk of jeopardizing that life. Most NASA probes, including the historic Voyager I and II spacecraft and especially the Mars rovers, Spirit and Opportunity, feature remote operation, but new missions and new planetary environments will demand new capabilities from the robotic explorers of the future. NASA has an acute interest in the development of specialized ROVs, as new lessons learned on Earth can be applied to new environments and increasingly complex missions in the future of space exploration.

2008-01-01

370

Data analysis to separate particles of different speed regimes and charges. [lunar ejecta and meteorite experiment and pioneer space probe data  

NASA Technical Reports Server (NTRS)

Although the instruments on the lunar ejecta and meteorite experiment (LEAM) and the Pioneer 8 and 9 space probes were essentially similar, a comparison of their results indicates that different sets of particles caused the different responses. On Pioneer, the events were caused by the impact of cosmic dust, the so-called beta particles expelled from the vicinity of the sun by solar radiation pressure, augmented by extremely high energy but definitely identifiable interstellar grains. On the moon, the events were due to the impact of slowly moving, highly charged lunar dust being propelled electrostatically across the terminator. Both theoretical analysis and experimental testing confirming these conclusions are discussed.

Wolf, H.

1977-01-01

371

Heat pipe cooled probe  

NASA Technical Reports Server (NTRS)

The basic heat pipe principle is employed to provide a self-contained passively cooled probe that may be placed into a high temperature environment. The probe consists of an evaporator region of a heat pipe and a sensing instrument. Heat is absorbed as the working fluid evaporates in the probe. The vapor is transported to the vapor space of the condenser region. Heat is dissipated from the condenser region and fins causing condensation of the working fluid, which returns to the probe by gravity and the capillary action of the wick. Working fluid, wick and condenser configurations and structure materials can be selected to maintain the probe within an acceptable temperature range.

Camarda, C. J. (inventor); Couch, L. M.

1984-01-01

372

The 2010 Transient Events in the Heliosheath - Comparing the Observations of IBEX and the Voyagers  

NASA Astrophysics Data System (ADS)

In the latter part of 2010, both Voyager 1 and Voyager 2 observed significant decreases of energetic particle intensity at energies 40keV-1MeV. The onset time and decay rate of this feature were very similar at both locations. Moreover, it was observed ~1 month earlier at Voyager 2 (which is not as deep into the heliosheath as Voyager 1), suggesting a large scale propagating temporal change in the heliosheath in the vicinity of the Voyagers (even though they are separated by ~130AU). During and subsequent to the period of this transient disturbance, the Interstellar Boundary Explorer (IBEX) was viewing Energetic Neutral Atom (ENA) emission (0.5-5 keV) from the region of the sky near the Voyagers, although the ENAs arrive months later due to the travel time from the heliosheath to 1 AU. In this study, we compare the ENA data taken by IBEX (0.5 to 5 keV) with the time-shifted in situ Voyager energetic ion observations ( >40 keV).

Demajistre, R.; Decker, R. B.; Funsten, H. O.; Janzen, P. H.; Krimigis, S. M.; McComas, D. J.; Reisenfeld, D. B.; Roelof, E. C.; Schwadron, N. A.; Vanderspek, R.

2011-12-01

373

Oberon - Color photometry from Voyager and its geological implications  

NASA Astrophysics Data System (ADS)

The surface of the Uranian satellite Oberon is characterized on the basis of ground-based and Voyager photometric observations. Disk-integrated phase-curve and disk-resolved data are presented in extensive tables, graphs, maps, and black-and-white and false-color images and discussed in terms of fits to the Hapke (1986) parameters, local variations in albedo and color, and their possible geological significance. It is found that most of the leading hemisphere is covered with dark materials like those in the crater floors, while the trailing hemisphere has patches of the dark material on a surface with a higher proportion of icy materials which are spectrally neutral.

Helfenstein, P.; Hillier, J.; Weitz, C.; Veverka, J.

1991-03-01

374

Voyager 2 photopolarimeter observations of the Uranian satellites  

NASA Technical Reports Server (NTRS)

The surfaces of the principal Uranian satellites are characterized on the basis of UV and IR geometric albedos, phase curves, and phase coefficients obtained in full-disk photopolarimetric observations during the Voyager 2 encounter with Uranus in January 1986. The data are presented in tables and graphs and found to be consistent with a heavily cratered terrain and loosely packed regolith. The Bond albedos are calculated as 0.22 + or - 0.1 for Ariel, 0.07 + or - 0.05 for Umbriel, 0.16 + or - 0.12 for Titania, and 0.19 + or - 0.22 for Oberon. The characteristics of the Uranian satellites indicate compositions (and probably formation conditions and surface-modification mechanisms) distinct from those of the Saturnian and Jovian satellites.

Nelson, Robert M.; Buratti, Bonnie J.; Wallis, Brad D.; Lane, Arthur L.; West, Robert A.

1987-01-01

375

Oberon - Color photometry from Voyager and its geological implications  

NASA Technical Reports Server (NTRS)

The surface of the Uranian satellite Oberon is characterized on the basis of ground-based and Voyager photometric observations. Disk-integrated phase-curve and disk-resolved data are presented in extensive tables, graphs, maps, and black-and-white and false-color images and discussed in terms of fits to the Hapke (1986) parameters, local variations in albedo and color, and their possible geological significance. It is found that most of the leading hemisphere is covered with dark materials like those in the crater floors, while the trailing hemisphere has patches of the dark material on a surface with a higher proportion of icy materials which are spectrally neutral.

Helfenstein, Paul; Hillier, John; Weitz, Catherine; Veverka, Joseph

1991-01-01

376

Inuit and Englishman: The Nunavut Voyages of Martin Frobisher  

NSDL National Science Digital Library

Sponsored by the Canadian Museum of Civilization, this site explores the voyage of Englishman Martin Frobisher to the New World in his efforts to find the Northwest Passage to Asia. Instead, he found Baffin Bay in the Canadian Northwest and its Inuit natives. The site is rich with both archaeological and historical information gleaned from sites on and near Kodlunarn Island where Frobisher and his men set up camp, and from historical documents held in British museums. Included here are historical and contemporary maps of the area, photographs of the archaeological sites, extracts from the logs of Frobisher and his men, and more. The site's objectivity makes the ironies and injustices that resulted from this encounter of European explorers with native peoples all the more apparent.

377

Exploring Our Dynamic Planet: Jules Verne Voyager, Jr.  

NSDL National Science Digital Library

Exploring Our Dynamic Planet consists of interactive tools, curriculum, and background materials that enable students to better visualize geophysical and geological processes and structures. A classroom module explores plate tectonics using geodesy results from GPS to observe and measure crustal motion. Tools include Jules Verne Voyager, Jr., which allows students to choose from a variety of base maps, add a number of geographic and geophysical overlays (e.g. plate boundaries, earthquake and volcano locations), and then superimpose crustal motion velocity vectors to observe how the tectonic plates move in relation to one another. The tool can be used to explore topics such as plate tectonics, seafloor spreading, and seasonal land and ocean productivity.

Meertens, Chuck

2002-02-28

378

1980 Aeronautics and Space Highlights  

NASA Technical Reports Server (NTRS)

This video includes Voyager 1 to Saturn, Solar Maximum Mission, sounding rockets/balloons, Space Shuttle, GOES 4 weather satellite, Mount St. Helen's Research, wind energy, rotor systems research aircraft, quiet shorthaul aircraft, AD-1 Scissor Wing, and automated pilot advisory system.

1980-01-01

379

1981 Aeronautics and Space Highlights  

NASA Technical Reports Server (NTRS)

This video presentation covers Shuttle flights 1 and 2, Spacelab, mobile workstation, Voyager 2 Saturn, Infrared Astronomy Satellite, Hubble Space Telescope, Kuiper Airborne Observatory, High Altitude Earth Survey, Landsat, aerodynamic research, electric cars, wind energy, XV-15, Quiet Shorthaul Research Aircraft, X-14 BVTOL, 40 x 80 Wind Tunnel, and turboprop research.

1981-01-01

380

Has the Sun Significantly Impacted Recent Voyager Observations?  

NASA Astrophysics Data System (ADS)

Using our models HAFSS (HAF Source Surface) and HHMS-PI (Hybrid Heliospheric Modeling System with Pickup Protons) we have been analyzing some of the recent (e.g., July 2012, etc.) solar events to determine if the effects of the events might be seen in the outer heliosphere, heliosheath, etc. Our analyses provide insights into the phenomena in these regions. Both models are three-dimensional (3D) time dependent simulations that use solar observations as input. HAFSS is a kinematic model. HHMS-PI is a numerical magnetohydrodynamic solar wind (SW) simulation model. Both HHMS-PI and HAFSS are ideally suited for these analyses since starting from the Sun they model the slowly evolving background SW and the impulsive, time-dependent events associated with solar activity (e.g., coronal mass ejections (CMEs). HHMS-PI/HAFSS make it possible to track interplanetary shocks as they propagate, interact, and evolve en route to various spacecraft (s/c) where they are observed. Our models have been used to reproduce s/c data from ACE to Ulysses, Cassini, and Voyagers 1 and 2. Our published results in refereed scientific journals showed that: a.) Our models naturally reproduce dynamic 3D spatially asymmetric effects observed throughout the heliosphere. b.) Pre-existing SW background conditions have a strong influence on the propagation of shock waves from solar events. c.) Time-dependence is a crucial aspect of interpreting s/c data. d.) Shock interactions resulting from multiple solar events lead to complicated time-series observations at individual s/c. We believe the answer to the question in the title of this abstract is: Yes, we do think the Sun has significantly impacted recent Voyager observations.

Intriligator, D. S.; Sun, W.; Detman, T. R.; Dryer, Ph. D., M.; Deehr, C. S.; Intriligator, J.; Webber, W. R.

2013-12-01

381

Voyager 2 in the uranian system: imaging science results.  

PubMed

Voyager 2 images of the southern hemisphere of Uranus indicate that submicrometersize haze particles and particles of a methane condensation cloud produce faint patterns in the atmosphere. The alignment of the cloud bands is similar to that of bands on Jupiter and Saturn, but the zonal winds are nearly opposite. At mid-latitudes (-70 degrees to -27 degrees ), where winds were measured, the atmosphere rotates faster than the magnetic field; however, the rotation rate of the atmosphere decreases toward the equator, so that the two probably corotate at about -20 degrees . Voyager images confirm the extremely low albedo of the ring particles. High phase angle images reveal on the order of 10(2) new ringlike features of very low optical depth and relatively high dust abundance interspersed within the main rings, as well as a broad, diffuse, low optical depth ring just inside the main rings system. Nine of the newly discovered small satellites (40 to 165 kilometers in diameter) orbit between the rings and Miranda; the tenth is within the ring system. Two of these small objects may gravitationally confine the e ring. Oberon and Umbriel have heavily cratered surfaces resembling the ancient cratered highlands of Earth's moon, although Umbriel is almost completely covered with uniform dark material, which perhaps indicates some ongoing process. Titania and Ariel show crater populations different from those on Oberon and Umbriel; these were probably generated by collisions with debris confined to their orbits. Titania and Ariel also show many extensional fault systems; Ariel shows strong evidence for the presence of extrusive material. About halfof Miranda's surface is relatively bland, old, cratered terrain. The remainder comprises three large regions of younger terrain, each rectangular to ovoid in plan, that display complex sets of parallel and intersecting scarps and ridges as well as numerous outcrops of bright and dark materials, perhaps suggesting some exotic composition. PMID:17812889

Smith, B A; Soderblom, L A; Beebe, R; Bliss, D; Boyce, J M; Brahic, A; Briggs, G A; Brown, R H; Collins, S A; Cook, A F; Croft, S K; Cuzzi, J N; Danielson, G E; Davies, M E; Dowling, T E; Godfrey, D; Hansen, C J; Harris, C; Hunt, G E; Ingersoll, A P; Johnson, T V; Krauss, R J; Masursky, H; Morrison, D; Owen, T; Plescia, J B; Pollack, J B; Porco, C C; Rages, K; Sagan, C; Shoemaker, E M; Sromovsky, L A; Stoker, C; Strom, R G; Suomi, V E; Synnott, S P; Terrile, R J; Thomas, P; Thompson, W R; Veverka, J

1986-07-01

382

Voyager 2 in the Uranian system: Imaging science results  

USGS Publications Warehouse

Voyager 2 images of the southern hemisphere of Uranus indicate that submicrometersize haze particles and particles of a methane condensation cloud produce faint patterns in the atmosphere. The alignment of the cloud bands is similar to that of bands on Jupiter and Saturn, but the zonal winds are nearly opposite. At mid-latitudes (-70?? to -27??), where winds were measured, the atmosphere rotates faster than the magnetic field; however, the rotation rate of the atmosphere decreases toward the equator, so that the two probably corotate at about -20??. Voyager images confirm the extremely low albedo of the ring particles. High phase angle images reveal on the order of 10 2 new ringlike features of very low optical depth and relatively high dust abundance interspersed within the main rings, as well as a broad, diffuse, low optical depth ring just inside the main ring system. Nine of the newly discovered small satellites (40 to 165 kilometers in diameter) orbit between the rings and Miranda; the tenth is within the ring system. Two of these small objects may gravitationally confine the ?? ring. Oberon and Umbriel have heavily cratered surfaces resembling the ancient cratered highlands of Earth's moon, although Umbriel is almost completely covered with uniform dark material, which perhaps indicates some ongoing process. Titania and Ariel show crater populations different from those on Oberon and Umbriel; these were probably generated by collisions with debris confined to their orbits. Titania and Ariel also show many extensional fault systems; Ariel shows strong evidence for the presence of extrusive material. About half of Miranda's surface is relatively bland, old, cratered terrain. The remainder comprises three large regions of younger terrain, each rectangular to ovoid in plan, that display complex sets of parallel and intersecting scarps and ridges as well as numerous outcrops of bright and dark materials, perhaps suggesting some exotic composition.

Smith, B.A.; Soderblom, L.A.; Beebe, R.; Bliss, D.; Boyce, J.M.; Brahic, A.; Briggs, G.A.; Brown, R.H.; Collins, S.A.; Cook, A.F., II; Croft, S.K.; Cuzzi, J.N.; Danielson, G.E.; Davies, M.E.; Dowling, T.E.; Godfrey, D.; Hansen, C.J.; Harris, C.; Hunt, G.E.; Ingersoll, A.P.; Johnson, T.V.; Krauss, R.J.; Masursky, H.; Morrison, D.; Owen, T.; Plescia, J.B.; Pollack, J.B.; Porco, C.C.; Rages, K.; Sagan, C.; Shoemaker, E.M.; Sromovsky, L.A.; Stoker, C.; Strom, R.G.; Suomi, V.E.; Synnott, S.P.; Terrile, R.J.; Thomas, P.; Thompson, W.R.; Veverka, J.

1986-01-01

383

The Solar Wind: Probing the Heliosphere with Multiple Spacecraft John D. Richardson  

E-print Network

1 The Solar Wind: Probing the Heliosphere with Multiple Spacecraft John D. Richardson Center of the Voyager spacecraft in the outer heliosphere, Ulysses at high latitudes, and multiple solar wind monitors near Earth provides a unique opportunity to study the global structure and evolution of the solar wind

Richardson, John

384

The abundances of constituents of Titan's atmosphere from the GCMS instrument on the Huygens probe  

Microsoft Academic Search

Saturn's largest moon, Titan, remains an enigma, explored only by remote sensing from Earth, and by the Voyager and Cassini spacecraft. The most puzzling aspects include the origin of the molecular nitrogen and methane in its atmosphere, and the mechanism(s) by which methane is maintained in the face of rapid destruction by photolysis. The Huygens probe, launched from the Cassini

H. B. Niemann; S. K. Atreya; S. J. Bauer; G. R. Carignan; J. E. Demick; R. L. Frost; D. Gautier; J. A. Haberman; D. N. Harpold; D. M. Hunten; G. Israel; J. I. Lunine; W. T. Kasprzak; T. C. Owen; M. Paulkovich; F. Raulin; E. Raaen

2005-01-01

385

Probing the Solar System  

ERIC Educational Resources Information Center

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…

Wilkinson, John

2013-01-01

386

Earth Exploration Toolbook Chapter: Investigating Earthquakes with ArcVoyager GIS  

NSDL National Science Digital Library

DATA: Recent and Historical Earthquake Data TOOL: ArcVoyager Special Edition GIS - Explore earthquake data and import them into a Geographic Information System (GIS). Analyze the data to predict where the next big earthquake will occur.

Carla McAuliffe

387

Dialectics of vision : the voyages of Louis I. Kahn, 1950-59  

E-print Network

Kahn's genre of travel sketches offers us a visual basis to map his philosophical meandering. This thesis addresses the sketches produced from Kahn's voyages around the Mediterranean in 1950-51 and 1959 with an aim to ...

Morshed, Adnan Zillur

1995-01-01

388

Voyager UVS measurements of Galactic Cosmic rays and their recent evolution  

NASA Astrophysics Data System (ADS)

Detectors of the Ultra-Violet Spectrographs on board the Voyagers have been recently found to provide independent measurements of galactic cosmic ray fluxes. Correlative studies with other Voyager Instruments show that the UVS detectors respond to the 100 MeV range. We will show the evolution of the measured flux over two solar cycles and compare it with the latitudinal and temporal variations of the solar wind derived from SOHO/SWAN data. We will include and discuss the most recent data up to Nov. 2012, in particular the recent abrupt increase observed by Voyager 1 at the beginning of May 2012 and the plateau that started. If the plateau is found to be constant, it could be the sign that Voyager 1 is measuring the genuine insterstellar cosmic flux, beyond the heliopause.

Lallement, R.; Quemerais, E.; Bertaux, J.; Sandel, B. R.; Koutroumpa, D.

2012-12-01

389

Environment-induced electrostatic discharges as the cause of Voyager 1 power-on resets  

NASA Technical Reports Server (NTRS)

The Pioneer and Voyager spacecraft all experienced anomalous behavior during their encounters with Jupiter. In particular, the Voyager 1 spacecraft experienced 42 electrical circuitry designed to protect the on-board computer from power fluctuations. Given the diversity of instrumentation and frequency of the anomalies observed by Voyager 1 in the inner magnetosphere of Jupiter, this set of data is particularly well suited as a case study. Although the nature of the anomalies clearly indicates a spacecraft-charging origin, the Voyager low-energy plasma data apparently imply absolute surface potentials of only a few tens of volts. It is thus difficult to explain the anomalies in terms of surface charging. The anomalies are, however, shown to be consistent with the hypothesis of internal charging of spacecraft parts and components.

Leung, P.; Whittlesey, A. C.; Garrett, H. B.; Robinson, P. A., Jr.

1986-01-01

390

Vertical mixing and methane photochemistry in the atmosphere of Uranus: Analysis of Voyager UVS occultation experiments  

NASA Technical Reports Server (NTRS)

Extensive capabilities were developed in the analysis of ultraviolet spectrometer (UVS) absorptive lightcurves. The application of these capabilities to the Voyager UVS data sets from Uranus and Neptune has provided significant findings regarding the stratospheres of these planets. In particular, the direct comparison between photochemical models and UVS measurements accomplished by these efforts is unique, and it helps to guarantee that the information returned by the Voyager 2 spacecraft is being used to the fullest extent possible.

Bishop, James

1991-01-01

391

In ecliptic observations of Jovian radio emissions by Ulysses - Comparison with Voyager results  

NASA Technical Reports Server (NTRS)

During the Ulysses inbound cruise to Jupiter the Unified Radio and Plasma Wave (URAP) experiment observed a variety of the planet's radio components in the frequency range below 1 MHz. Most of these emissions were already detected by the Voyager Radio Astronomy and Plasma Wave experiments, however, with much less sensitivity and different spectral coverage. These different radio components within the URAP dynamic spectra are identified, and their appearance with the previous Voyager observations are compared.

Lecacheux, A.; Pedersen, B. M.; Zarka, PH.; Aubier, M. G.; Desch, M. D.; Farrell, W. M.; Kaiser, M. L.; Macdowall, R. J.; Stone, R. G.

1992-01-01

392

VOYAGER 2 - LIFTS OFF ATOP A TITAN/CENTAUR FROM LAUNCH COMPLEX 41  

NASA Technical Reports Server (NTRS)

VOYAGER 2 - LIFTS OFF ATOP A TITAN/CENTAUR FROM LAUNCH COMPLEX 41 KSC-77PC-0269.01 101-KSC-77PC-269.1, P-19191, ARCHIVE-04107 Titan/Centaur-7 lifted off from Complex 41 at Cape Canaveral Air Force Station at 10:29 A.M. EDT today to send an 1,800-pound Voyager on an odyssey through the outer planets.

1977-01-01

393

Magnetic fields in the distant heliosphere approaching solar minimum: Voyager 1 and 2 observations during 1994  

Microsoft Academic Search

During 1994, Voyager 2 (V2) was at a heliocentric distance (R) = 43.4 AU and latitude (s\\/c) - 11.9øS, while Voyager 1 (V1) was at (R) = 56.3 AU and (s\\/c) = 32.5øN. The mean magnetic field strength observed by V1 during 1994 was 0.05 nT, the weakest and most distant magnetic field ever measured in situ. A bimodal distribution

L. F. Burlaga; N. F. Ness

1996-01-01

394

Magnetic fields in the distant heliosphere approaching solar minimum: Voyager 1 and 2 observations during 1994  

Microsoft Academic Search

During 1994, Voyager 2 (V2) was at a heliocentric distance =43.4 AU and latitude =11.9°S, while Voyager 1 (V1) was at =56.3 AU and =32.5°N. The mean magnetic field strength observed by V1 during 1994 was 0.05 nT, the weakest and most distant magnetic field ever measured in situ. A bimodal distribution of azimuthal magnetic field directions was observed by

L. F. Burlaga; N. F. Ness

1996-01-01

395

Jovian modulation of interplanetary electrons as observed with Voyagers 1 and 2  

NASA Technical Reports Server (NTRS)

The release of magnetospheric electrons from Jupiter into interplanetary space is modulated by the Jovian rotation period. The Voyager 1 and 2 observations showed that the modulation period agrees on the average with the synodic period of Jupiter (9h 55m 33.12s), but over intervals of weeks it can differ from the synodic period by several minutes. The lack of exact synchronization is attributed to changes of the plasma population in the Jovian magnetosphere. The Jovian modulation appears to be a persistent feature of the interaction between the solar wind and the magnetosphere and the disappearance of the modulation away from Jupiter is attributed to interplanetary propagation conditions. This leads to the following limits on the diffuse coefficient for interplanetary electrons: kappa perpendicular is or = 8 x 10 to the 19th power sq cm/s and kappa parallel is or = 10 to the 21st power sq cm/s. Modulation was still detectable at 3.8 A.U. behind Jupiter in the far magnetotail. This requires a mean free path in the tail 0.75 A.U. and good field connection along the tail to Jupiter.

Schardt, A. W.; Mcdonald, F. B.; Trainor, J. H.

1982-01-01

396

Outer Planets/Solar Probe Project: Solar Probe  

NASA Technical Reports Server (NTRS)

Solar Probe, the first mission to the Sun and the third of three missions in NASA's Outer Solar System/Solar Probe Program, is a voyage of exploration, discovery, and comprehension. This near-Sun flyby will provide in situ measurements in the solar corona and high-resolution pictures and magnetograms of the photosphere and polar atmosphere. These measurements are also needed as "ground truth" for interpreting the many measurements of the Sun and solar activity that have been made from a distance of 1 AU. Solar Probe is scheduled for launch in February 2007. It will arrive at the Sun along a polar trajectory perpendicular to the Sun-Earth line with a perihelion of 4 solar radii (R(sub s)) from the Sun's center. Two perihelion passages will occur, the first in 2010 (near solar sunspot maximum) and the second in 2015 (near solar minimum) ensuring measurement of both coronal hole and streamer-related solar wind properties. To reach the Sun, probe must first fly to Jupiter and use a gravity assist to lose its angular momentum about the Sun. The imaging and in situ miniaturized instruments will provide the first 3-dimensional view of the corona, high spatial- and temporal-resolutions of the magnetic fields, and helioseismic measurements of the polar regions, as well as sporadic high-spatial-resolution local sampling of plasmas and fields at all latitudes.

Tsurutani, B. T.

2000-01-01

397

Advanced radioisotope power sources for future deep space missions  

Microsoft Academic Search

The use of Radioisotope Thermoelectric Generators (RTGs) has been well established for deep space mission applications. The success of the Voyager, Galileo, Cassini and numerous other missions proved the efficacy of these technologies in deep space. Future deep space missions may also require Advanced Radioisotope Power System (ARPS) technologies to accomplish their goals. In the Exploration of the Solar System

Erik N. Nilsen

2001-01-01

398

Particles and fields measurements at Neptune with Voyager 2  

NASA Technical Reports Server (NTRS)

The first results of measurements performed on the Voyager 2 spacecraft with the Neptune system on August 24-28, 1989 are summarized. These include measurements of the magnetic field, plasma, energetic and high energy particles, plasma waves and radio emissions, and additional information relating to UV emissions. The planetary magnetic field outside about 4 R(N) may be described by an offset, tilted, dipole of moment 0.133 Gauss-R(N) exp 3; inside that distance the field is dominated by higher order terms. Plasma densities are found to be generally low (about 5 exp -3/cu cm), except at magnetic equatorial crossings when densities are up to about 1/cu cm. A variety of plasma wave emissions were seen, including chorus, hiss, electroncyclotron waves, and upper hybrid resonance in the inner magnetosphere. The measured flux of soft electrons and ions over the polar region of about 2 x 10 exp -3 erg/sq cm sec results in an estimated power input of about 3 x 10 exp 7 W, which is substantially less than that at other planets.

Krimigis, S. M.

1992-01-01

399

Voyager 2 encounter with Ganymede's wake: hydromagnetic and electrodynamic processes  

SciTech Connect

Voyager 2's passage through corotation wake region of Ganymede found disturbances in the energetic particle and magnetic field data. To explain the nature of disturbances, an investigation of the interaction of the Jovian plasma with Ganymede is carried out. A series of computer simulations, supported by appropriate theories, are made. Three different aspects of the interaction are studied: (i) A magnetic field model is proposed to describe Alfvenic disturbances caused by Ganymede. Numerical simulations show that the interaction of ensembles of ions with perturbed fields modulates the energies of the ions. The amount of modulation depends on the Alfven mach number of the ambient plasma, the ion energy, and the pitch angle of the ions. (ii) The electrodynamic processes associated with the plasma-Ganymede interaction and the plasma expansion into the cavity are simulated using a particle-in-cell method. The distribution of ions, potentials, ion and electron thermal and drift energies in the wake region are obtained. (iii) Using linear MHD theory, conditions for excitation and growth of the Kelvin-Helmholtz instability are investigated. Theoretical conditions for the existence of magnetosonic waves and transverse Alfven waves are also examined.

Tariq, G.F.

1984-01-01

400

Jupiter's Atmospheric Temperatures: From Voyager IRIS to Cassini CIRS  

NASA Technical Reports Server (NTRS)

Retrievals run on Cassini Composite Infrared Spectrometer data obtained during the distant Jupiter flyby have been used to generate global temperature maps of the planet in the troposphere and stratosphere. Similar retrievals were performed on Voyager 1 IRIS data and have provided the first detailed IRIS map of the stratosphere. In both data sets, high latitude troposphere temperatures are presented for the first time, and the meridional gradients indicate the presence of circumpolar jets. Thermal winds were calculated for each data set and show strong vertical shears in the zonal winds at low latitudes. The temperatures retrieved from the two spacecraft were also compared with yearly ground-based data obtained over the intervening two decades. Tropospheric temperatures reveal gradual changes at low latitudes, with little obvious seasonal or short-term variation (Orton et al. 1994). Stratospheric temperatures show much more complicated behavior over short timescales, consistent with quasi-quadrennial oscillations at low latitudes, as suggested in prior analyses of shorter intervals of ground- based data (Orton et al. 1991, Friedson 1999). A scaling analysis indicates that meridional motions, mechanically forced by wave or eddy convergence, play an important role in modulating the temperatures and winds in the upper troposphere and stratosphere on seasonal and shorter time scales. At latitudes away from the equator, the mechanical forcing can be derived simply from a temporal record of temperature and its vertical derivative. Ground-based observations with improved vertical resolution and/or long-term monitoring from spacecraft are required for this purpose.

Simon-Miller, Amy A.; Conrath, Barney J.; Gierasch, Peter J.; Orton, Glenn S.; Achterberg, Richard K.; Flasar, F. Michael; Fisher, Brendan

2004-01-01

401

VOYAGER UVS Lyman-alpha reanalysis: 1993-2011  

NASA Astrophysics Data System (ADS)

We present an updated analysis of Voyager UVS Lyman-alpha data recorded since 1993, and discuss three aspects. i) A new reduction of the data set has been performed. It reveals that the V1 and V2 UVS detectors have recorded an increasing background that must be due to ambient energetic particles in the MeV range. For V1, measurements are available up to present time. After a series of fluctuations corresponding to the termination shock approach and crossing, the background is now increasing smoothly again. Although the energy range influencing UVS is uncertain, those new measurements may complement other particle data. ii) The Ly-alpha signal is compared to radiative transfer calculations applied to a self-consistent two-component heliospheric model, and shown to be in excellent agreement with the expected sky pattern. iii) A new method of treatment adapted to low galactic latitudes and the presence of dust-scattered galactic UV background has been developed, in order to facilitate disentangling the major heliospheric contribution and a galactic contribution at Lyman-alpha.

Lallement, R.; Quemerais, E.; Sandel, B. R.; Izmodenov, V.; Bertaux, J.

2011-12-01

402

Magnetic field experiment for Voyagers 1 and 2  

NASA Technical Reports Server (NTRS)

The magnetic field experiment to be carried on the Voyager 1 and 2 missions consists of dual low field (LFM) and high field magnetometer (HFM) systems. The dual systems provide greater reliability and, in the case of the LFM's, permit the separation of spacecraft magnetic fields from the ambient fields. Additional reliability is achieved through electronics redundancy. The wide dynamic ranges of plus or minus 0.5G for the LFM's and plus or minus 20G for the HFM's, low quantization uncertainty of plus or minus 0.002 gamma in the most sensitive (plus or minus 8 gamma) LFM range, low sensor RMS noise level of 0.006 gamma, and use of data compaction schemes to optimize the experiment information rate all combine to permit the study of a broad spectrum of phenomena during the mission. Planetary fields at Jupiter, Saturn, and possibly Uranus; satellites of these planets; solar wind and satellite interactions with the planetary fields; and the large-scale structure and microscale characteristics of the interplanetary magnetic field are studied. The interstellar field may also be measured.

Behannon, K. W.; Aluna, M. H.; Burlaga, L. F.; Lepping, R. P.; Ness, N. F.; Neubauer, F. M.

1977-01-01

403

Current Sheets in the Heliosheath: Voyager 1, 2009  

NASA Technical Reports Server (NTRS)

We identified all of the current sheets for which we have relatively complete and accurate magnetic field (B) data from Voyager 1 (V1) from days of year (DOYs) 1 to 331, 2009, which were obtained deep in the heliosheath between 108.5 and 111.8 AU. Three types of current sheets were found: (1) 15 proton boundary layers (PBLs), (2) 10 and 3 magnetic holes and magnetic humps, respectively, and (3) 3 sector boundaries. The magnetic field strength changes across PBL, and the profile B(t) is linearly related to the hyperbolic tangent function, but the direction of B does not change. For each of the three sector boundaries, B rotated in a plane normal to the minimum variance direction, and the component of B along the minimum variance direction was zero within the uncertainties, indicating that the sector boundaries were tangential discontinuities. The structure of the sector boundaries was not as simple as that for PBLs. The average thickness of magnetic holes and humps (approx.30 RL) was twice that of the PBLs (approx.15 RL). The average thickness of the current sheets associated with sector boundaries was close to the thickness of the PBLs. Our observations are consistent with the hypothesis that magnetic holes and humps are solitons, which are initiated by the mirror mode instability, and evolve by nonlinear kinetic plasma processes to pressure balanced structures maintained by magnetization currents and proton drift currents in the gradients of B.

Burlaga, L. F.; Ness, N. F.

2011-01-01

404

The Voyage of the Slave Ship Sally: 1764-1765  

NSDL National Science Digital Library

In 1764, a one hundred ton ship called the Sally set sail from Providence, Rhode Island to West Africa on a slaving voyage. The vessel was owned by Nicholas Brown and Company, which was a local merchant firm run by four brothers. The records of this particular venture are preserved in the John Carter Brown Library at Brown University and this remarkable website offers all of the records that remain from this journey. First-time visitors should peruse the "History" area to read a few thematic essays on different aspects of the Sally's journey, which cover topics like "On the African Coast", "The Middle Passage", and "Fitting out the Sally". After that, they should visit "The Documents" area. Here they will find letters, invoices, legal documents, and trade books that tell the story of how the ship was outfitted, who sailed aboard here, and what cargo she carried. This project is another well-done endeavor created by the Center for Digital Initiatives, and it merits several visits.

405

Real space tests of the statistical isotropy and Gaussianity of the Wilkinson Microwave Anisotropy Probe cosmic microwave background data  

SciTech Connect

We introduce and analyze a method for testing statistical isotropy and Gaussianity and apply it to the Wilkinson Microwave Anisotropy Probe (WMAP) cosmic microwave background (CMB) foreground reduced temperature maps. We also test cross-channel difference maps to constrain levels of residual foreground contamination and systematic uncertainties. We divide the sky into regions of varying size and shape and measure the first four moments of the one-point distribution within these regions, and using their simulated spatial distributions we test the statistical isotropy and Gaussianity hypotheses. By randomly varying orientations of these regions, we sample the underlying CMB field in a new manner, that offers a richer exploration of the data content, and avoids possible biasing due to a single choice of sky division. In our analysis we account for all two-point correlations between different regions and also show the impact on the results when these correlations are neglected. The statistical significance is assessed via comparison with realistic Monte Carlo simulations. We find the three-year WMAP maps to agree well with the isotropic, Gaussian random field simulations as probed by regions corresponding to the angular scales ranging from 6 Degree-Sign to 30 Degree-Sign at 68% confidence level (CL). We report a strong, anomalous (99.8% CL) dipole 'excess' in the V band of the three-year WMAP data and also in the V band of the WMAP five-year data (99.3% CL). Using our statistics, we notice large scale hemispherical power asymmetry, and find that it is not highly statistically significant in the WMAP three-year data ( Less-Than-Or-Equivalent-To 97%) at scales l{<=}40. The significance is even smaller if multipoles up to l=1024 are considered ({approx}90% CL). We give constraints on the amplitude of the previously proposed CMB dipole modulation field parameter. We find some hints of foreground contamination in the form of a locally strong, anomalous kurtosis excess in the Q+V +W co-added map, which however is not significant globally. We easily detect the residual foregrounds in cross-band difference maps at rms level {approx}<7 {mu}K (at scales {approx}>6{sup o}) and limit the systematical uncertainties to {approx}<1.7 {mu}K (at scales {approx}>30{sup o})

Lew, Bartosz, E-mail: blew@a.phys.nagoya-u.ac.jp [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan) [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Department of Physics and Astrophysics, Nagoya University, Nagoya 464-8602 (Japan); Torun Centre for Astronomy, Nicolaus Copernicus University, ulica Gagarina 11, 87-100 Torun (Poland)

2008-08-15

406

Radioisotope Power: A Key Technology for Deep Space Exploration  

NASA Technical Reports Server (NTRS)

A Radioisotope Power System (RPS) generates power by converting the heat released from the nuclear decay of radioactive isotopes, such as Plutonium-238 (Pu-238), into electricity. First used in space by the U.S. in 1961, these devices have enabled some of the most challenging and exciting space missions in history, including the Pioneer and Voyager probes to the outer solar system; the Apollo lunar surface experiments; the Viking landers; the Ulysses polar orbital mission about the Sun; the Galileo mission to Jupiter; the Cassini mission orbiting Saturn; and the recently launched New Horizons mission to Pluto. Radioisotopes have also served as a versatile heat source for moderating equipment thermal environments on these and many other missions, including the Mars exploration rovers, Spirit and Opportunity. The key advantage of RPS is its ability to operate continuously, independent of orientation and distance relative to the Sun. Radioisotope systems are long-lived, rugged, compact, highly reliable, and relatively insensitive to radiation and other environmental effects. As such, they are ideally suited for missions involving long-lived, autonomous operations in the extreme conditions of space and other planetary bodies. This paper reviews the history of RPS for the U.S. space program. It also describes current development of a new Stirling cycle-based generator that will greatly expand the application of nuclear-powered missions in the future.

Schmidt, George; Sutliff, Tom; Dudzinski, Leonard

2008-01-01

407

Space  

NSDL National Science Digital Library

This unit begins by introducing students to the historical motivation for space exploration. They learn about the International Space Station, including current and futuristic ideas that engineers are designing to propel space research. Then they learn about the physical properties of the Moon, and think about what types of products engineers would need to design in order for humans to live on the Moon. Lastly, students learn some descriptive facts about asteroids, such as their sizes and how that relates to the potential danger of an asteroid colliding with the Earth.

Integrated Teaching And Learning Program

408

Climate windows for Polynesian voyaging to New Zealand and Easter Island.  

PubMed

Debate about initial human migration across the immense area of East Polynesia has focused upon seafaring technology, both of navigation and canoe capabilities, while temporal variation in sailing conditions, notably through climate change, has received less attention. One model of Polynesian voyaging observes that as tradewind easterlies are currently dominant in the central Pacific, prehistoric colonization canoes voyaging eastward to and through central East Polynesia (CEP: Society, Tuamotu, Marquesas, Gambier, Southern Cook, and Austral Islands) and to Easter Island probably had a windward capacity. Similar arguments have been applied to voyaging from CEP to New Zealand against prevailing westerlies. An alternative view is that migration required reliable off-wind sailing routes. We investigate the marine climate and potential voyaging routes during the Medieval Climate Anomaly (MCA), A.D. 800-1300, when the initial colonization of CEP and New Zealand occurred. Paleoclimate data assimilation is used to reconstruct Pacific sea level pressure and wind field patterns at bidecadal resolution during the MCA. We argue here that changing wind field patterns associated with the MCA provided conditions in which voyaging to and from the most isolated East Polynesian islands, New Zealand, and Easter Island was readily possible by off-wind sailing. The intensification and poleward expansion of the Pacific subtropical anticyclone culminating in A.D. 1140-1260 opened an anomalous climate window for off-wind sailing routes to New Zealand from the Southern Austral Islands, the Southern Cook Islands, and Tonga/Fiji Islands. PMID:25267611

Goodwin, Ian D; Browning, Stuart A; Anderson, Atholl J

2014-10-14

409

Probing the space-time geometry around black hole candidates with the resonance models for high-frequency QPOs and comparison with the continuum-fitting method  

SciTech Connect

Astrophysical black hole candidates are thought to be the Kerr black hole predicted by General Relativity. However, in order to confirm the Kerr-nature of these objects, we need to probe the geometry of the space-time around them and check that observations are consistent with the predictions of the Kerr metric. That can be achieved, for instance, by studying the properties of the electromagnetic radiation emitted by the gas in the accretion disk. The high-frequency quasi-periodic oscillations observed in the X-ray flux of some stellar-mass black hole candidates might do the job. As the frequencies of these oscillations depend only very weakly on the observed X-ray flux, it is thought they are mainly determined by the metric of the space-time. In this paper, I consider the resonance models proposed by Abramowicz and Kluzniak and I extend previous results to the case of non-Kerr space-times. The emerging picture is more complicated than the one around a Kerr black hole and there is a larger number of possible combinations between different modes. I then compare the bounds inferred from the twin peak high-frequency quasi-periodic oscillations observed in three micro-quasars (GRO J1655-40, XTE J1550-564, and GRS 1915+105) with the measurements from the continuum-fitting method of the same objects. For Kerr black holes, the two approaches do not provide consistent results. In a non-Kerr geometry, this conflict may be solved if the observed quasi-periodic oscillations are produced by the resonance ?{sub ?}:?{sub r} = 3:1, where ?{sub ?} and ?{sub r} are the two epicyclic frequencies. It is at least worth mentioning that the deformation from the Kerr solution required by observations would be consistent with the one suggested in another recent work discussing the possibility that steady jets are powered by the spin of these compact objects.

Bambi, Cosimo, E-mail: Cosimo.Bambi@physik.uni-muenchen.de [Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universität München, Theresienstraße 37, D-80333 Munich (Germany)

2012-09-01

410

Voyager 1 in the foreshock, termination shock, and heliosheath.  

PubMed

Voyager 1 (V1) began measuring precursor energetic ions and electrons from the heliospheric termination shock (TS) in July 2002. During the ensuing 2.5 years, average particle intensities rose as V1 penetrated deeper into the energetic particle foreshock of the TS. Throughout 2004, V1 observed even larger, fluctuating intensities of ions from 40 kiloelectron volts (keV) to >/=50 megaelectron volts per nucleon and of electrons from >26 keV to >/=350 keV. On day 350 of 2004 (2004/350), V1 observed an intensity spike of ions and electrons that was followed by a sustained factor of 10 increase at the lowest energies and lesser increases at higher energies, larger than any intensities since V1 was at 15 astronomical units in 1982. The estimated solar wind radial flow speed was positive (outward) at approximately +100 kilometers per second (km s(-1)) from 2004/352 until 2005/018, when the radial flows became predominantly negative (sunward) and fluctuated between approximately -50 and 0 km s(-1) until about 2005/110; they then became more positive, with recent values (2005/179) of approximately +50 km s(-1). The energetic proton spectrum averaged over the postshock period is apparently dominated by strongly heated interstellar pickup ions. We interpret these observations as evidence that V1 was crossed by the TS on 2004/351 (during a tracking gap) at 94.0 astronomical units, evidently as the shock was moving radially inward in response to decreasing solar wind ram pressure, and that V1 has remained in the heliosheath until at least mid-2005. PMID:16179469

Decker, R B; Krimigis, S M; Roelof, E C; Hill, M E; Armstrong, T P; Gloeckler, G; Hamilton, D C; Lanzerotti, L J

2005-09-23

411

COMPRESSIBLE 'TURBULENCE' OBSERVED IN THE HELIOSHEATH BY VOYAGER 2  

SciTech Connect

This paper describes the multiscale structure of the compressible 'turbulence' observed in the high-resolution (48 s) observations of the magnetic field strength B made by Voyager 2 (V2) in the heliosheath behind the termination shock from 2007 DOY 245.0-300.8 and in a unipolar region from 2008 DOY 2.9-75.6. The magnetic field strength is highly variable on scales from 48 s to several hours in both intervals. The distributions of daily averages and 48 s averages of B are lognormal in the post-termination shock (TS) region and Gaussian in the unipolar region, respectively. The amplitudes of the fluctuations were greater in the post-TS region than in the unipolar region, at scales less than several hours. The multiscale structure of the increments of B is described by the q-Gaussian distribution of nonextensive statistical mechanics on all scales from 48 s to 3.4 hr in the unipolar region and from 48 s to 6.8 hr in the post-TS region, respectively. The amplitudes of the fluctuations of increments of B are larger in the post-TS region than in the unipolar region at all scales. The probability density functions of the increments of B are non-Gaussian at all scales in the unipolar region, but they are Gaussian at the largest scales in the post-TS region. Time series of the magnitude and direction of B show that the fluctuations are highly compressive. The small-scale fluctuations are a mixture of coherent structures (semi-deterministic structures) and random structures, which vary significantly from day to day. Several types of coherent structures were identified in both regions.

Burlaga, L. F. [Geospace Physics Laboratory, Code 673, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Ness, N. F., E-mail: Leonard.F.Burlaga@NASA.go, E-mail: nfnudel@yahoo.co [Institute for Astrophysics and Computational Sciences, Catholic University of America, Washington DC 20064 (United States)

2009-09-20

412

Voyager 2 Color Image of Enceladus, Almost Full Disk  

NASA Technical Reports Server (NTRS)

This color Voyager 2 image mosaic shows the water-ice-covered surface of Enceladus, one of Saturn's icy moons. Enceladus' diameter of just 500 km would fit across the state of Arizona, yet despite its small size Enceladus exhibits one of the most interesting surfaces of all the icy satellites. Enceladus reflects about 90% of the incident sunlight (about like fresh-fallen snow), placing it among the most reflective objects in the Solar System. Several geologic terrains have superposed crater densities that span a factor of at least 500, thereby indicating huge differences in the ages of these terrains. It is possible that the high reflectivity of Enceladus' surface results from continuous deposition of icy particles from Saturn's E-ring, which in fact may originate from icy volcanoes on Enceladus' surface. Some terrains are dominated by sinuous mountain ridges from 1 to 2 km high (3300 to 6600 feet), whereas other terrains are scarred by linear cracks, some of which show evidence for possible sideways fault motion such as that of California's infamous San Andreas fault. Some terrains appear to have formed by separation of icy plates along cracks, and other terrains are exceedingly smooth at the resolution of this image. The implication carried by Enceladus' surface is that this tiny ice ball has been geologically active and perhaps partially liquid in its interior for much of its history. The heat engine that powers geologic activity here is thought to be elastic deformation caused by tides induced by Enceladus' orbital motion around Saturn and the motion of another moon, Dione.

1990-01-01

413

Plasma observations near saturn: initial results from voyager 1.  

PubMed

Extensive measurements of low-energy plasma electrons and positive ions were made during the Voyager 1 encounter with Saturn and its satellites. The magnetospheric plasma contains light and heavy ions, probably hydrogen and nitrogen or oxygen; at radial distances between 15 and 7 Saturn-radii (Rs) on the inbound trajectory, the plasma appears to corotate with a velocity within 20 percent of that expected for rigid corotation. The general morphology of Saturn's magnetosphere is well represented by a plasma sheet that extends from at least 5 to 17 Rs, is symmetrical with respect to Saturn's equatorial plane and rotation axis, and appears to be well ordered by the magnetic shell parameter L (which represents the equatorial distance of a magnetic field line measured in units of Rs). Within this general configuration, two distinct structures can be identified: a central plasma sheet observed from L = 5 to L = 8 in which the density decreases rapidly away from the equatorial plane, and a more extended structure from L = 7 to beyond 18 Rs in which the density profile is nearly flat for a distance +/- 1.8 Rs off the plane and falls rapidly thereafter. The encounter with Titan took place inside the magnetosphere. The data show a clear signature characteristic of the interaction between a subsonic corotating magnetospheric plasma and the atmospheric or ionospheric exosphere of Titan. Titan appears to be a significant source of ions for the outer magnetosphere. The locations of bow shock crossings observed inbound and outbound indicate that the shape of the Saturnian magnetosphere is similar to that of Earth and that the position of the stagnation point scales approximately as the inverse one-sixth power of the ram pressure. PMID:17783833

Bridge, H S; Belcher, J W; Lazarus, A J; Olbert, S; Sullivan, J D; Bagenal, F; Gazis, P R; Hartle, R E; Ogilvie, K W; Scudder, J D; Sittler, E C; Eviatar, A; Siscoe, G L; Goertz, C K; Vasyliunas, V M

1981-04-10

414

Probing planar defects in nanoparticle superlattices by 3D small-angle electron diffraction tomography and real space imaging.  

PubMed

We demonstrate how the acquisition and processing of 3D electron diffraction data can be extended to characterize structural features on the mesoscale, and show how lattice distortions in superlattices of self-assembled spherical Pd nanoparticles can be quantified by three-dimensional small-angle electron diffraction tomography (3D SA-EDT). Transmission electron microscopy real space imaging and 3D SA-EDT reveal a high density of stacking faults that was related to a competition between fcc and hcp arrangements during assembly. Information on the orientation of the stacking faults was used to make analogies between planar defects in the superlattices and Shockley partial dislocations in metallic systems. PMID:25292411

Mayence, Arnaud; Wang, Dong; Salazar-Alvarez, German; Oleynikov, Peter; Bergström, Lennart

2014-11-21

415

Probing planar defects in nanoparticle superlattices by 3D small-angle electron diffraction tomography and real space imaging  

NASA Astrophysics Data System (ADS)

We demonstrate how the acquisition and processing of 3D electron diffraction data can be extended to characterize structural features on the mesoscale, and show how lattice distortions in superlattices of self-assembled spherical Pd nanoparticles can be quantified by three-dimensional small-angle electron diffraction tomography (3D SA-EDT). Transmission electron microscopy real space imaging and 3D SA-EDT reveal a high density of stacking faults that was related to a competition between fcc and hcp arrangements during assembly. Information on the orientation of the stacking faults was used to make analogies between planar defects in the superlattices and Shockley partial dislocations in metallic systems.We demonstrate how the acquisition and processing of 3D electron diffraction data can be extended to characterize structural features on the mesoscale, and show how lattice distortions in superlattices of self-assembled spherical Pd nanoparticles can be quantified by three-dimensional small-angle electron diffraction tomography (3D SA-EDT). Transmission electron microscopy real space imaging and 3D SA-EDT reveal a high density of stacking faults that was related to a competition between fcc and hcp arrangements during assembly. Information on the orientation of the stacking faults was used to make analogies between planar defects in the superlattices and Shockley partial dislocations in metallic systems. Electronic supplementary information (ESI) available: Material characterization, simulated and experimental 3D reciprocal volume reconstruction and TEM bright-field images of nanoparticle superlattices. See DOI: 10.1039/c4nr04156a

Mayence, Arnaud; WangPresent Address: Department Of Chemical Engineering, Northeast Dianli University, Jilin, China., Dong; Salazar-Alvarez, German; Oleynikov, Peter; Bergström, Lennart

2014-10-01

416

A solution methodology for exact design space exploration in a three-dimensional design space  

Microsoft Academic Search

This paper describes an exact solution methodology, implemented in Rensselaer's Voyager design space exploration system, for solving the scheduling problem in a three-dimensional (3-D) design space: the usual two-dimensional (2-D) design space (which trades off area and schedule length), plus a third dimension representing clock length. Unlike design space exploration methodologies which rely on bounds or estimates, this methodology is

Samit Chaudhuri; S. A. Blthye; Robert A. Walker

1997-01-01

417

The far-ultraviolet energy distribution of Sirius B from Voyager 2  

NASA Technical Reports Server (NTRS)

Observations of Sirius obtained with the Voyager 2 ultraviolet spectrometer clearly reveal the presence of flux from the white dwarf Sirius B at wavelengths between 950 and 1100 A. These observations are in good agreement with all previous ultraviolet observations of Sirius B, and in particular with the IUE observations of Boehm-Vitense, Dettmann, and Kapranidis. A joint analysis of the Voyager 2 and IUE observations yields a temperature range of 26,000-28,000 K. A reexamination of current ultraviolet, visible, and X-ray observations produces good general agreement, but no single, mutually consistent, temperature for Sirius B. The Voyager 2 observations can be used to place a firm upper limit of 28,000 K on the temperature of Sirius B.

Holberg, J. B.; Wesemael, F.; Hubeny, I.

1984-01-01

418

Ray tracing of Jovian decametric radiation from Southern and Northern Hemisphere sources - Comparison with Voyager observations  

NASA Technical Reports Server (NTRS)

The Voyager 1 and 2 Planetary Radio Astronomy observations of Io-dependent decametric (DAM) radiation originating from the Southern Hemisphere of Jupiter were compared with the results of three-dimensional model ray tracing calculations of the DAM radiation. The ray trajectories for sources located at constant sub-Io longitudes of 260 and 300 deg were computed for both the Northern and the Southern Jovian Hemisphere sources. The model results of wave propagation agree with the Voyager observations obtained with Io located at 260 and 300 deg in Jovian system III longitude. The agreement between the Voyager observations and the model ray tracings allows identification of the origin of several of the emission components.

Menietti, J. Douglas; Green, James L.; Six, N. Frank; Gulkis, S.

1987-01-01

419

Suprathermal ions in the solar wind from the Voyager spacecraft: Instrument modeling and background analysis  

NASA Astrophysics Data System (ADS)

Using publicly available data from the Voyager Low Energy Charged Particle (LECP) instruments, we investigate the form of the solar wind ion suprathermal tail in the outer heliosphere inside the termination shock. This tail has a commonly observed form in the inner heliosphere, that is, a power law with a particular spectral index. The Voyager spacecraft have taken data beyond 100 AU, farther than any other spacecraft. However, during extended periods of time, the data appears to be mostly background. We have developed a technique to self-consistently estimate the background seen by LECP due to cosmic rays using data from the Voyager cosmic ray instruments and a simple, semi-analytical model of the LECP instruments.

Randol, B. M.; Christian, E. R.

2015-01-01

420

Interaction of Eddies and Mean Zonal Flow on Jupiter as Inferred from Voyager 1 and 2 Images  

Microsoft Academic Search

Voyager 1 and 2 narrow-angle frames were used to obtain displacements of features at resolutions of 130 km over time intervals of 1 Jovian rotation. The zonal velocity d was constant to 1.5% during the 4 months between the Voyager 1 and 2 encounters. The latitudes of the zonal jet maxima (extrema of ) are the same as inferred from

Andrew P. Ingersoll; Reta F. Beebe; Jim L. Mitchell; Glenn W. Garneau; Gary M. Yagi; Jan-Peter Müller

1981-01-01

421

C over: Voyager 2 WilS one rniliion  

E-print Network

SCribed in this report, include ASASI ENSCE and the Space Reactor Power System (SP- 700). In 7985 we reexamined our Director's Message 2 IntroductIOn 4 Flight Projects 6 Space Science 18 Geodynamics 28 Materials Science 32 and the NatIonal AeronautIcs and Space AdminIstration for the period January 7 through December 37, 7985 JET

Waliser, Duane E.

422

The magnetic-anomaly model of the Jovian magnetosphere - A post-Voyager assessment  

NASA Technical Reports Server (NTRS)

Predictions previously put forth (Dessler and Vasyliunas, 1979) as tests for the magnetic-anomaly model (in which the anomalously weak magnetic field region in the northern hemisphere of Jupiter influences the outer Jovian magnetosphere by one or more plasma interaction processes) are reexamined in the light of Voyager and other recent observations. With regard to the prediction of a restricted longitude range of enhanced interaction between Io and Jupiter's ionosphere, the longitudinal asymmetries seen both in ground-based observations of sulfur emissions from the Io torus and in Voyager observations of Jovian auroral emissions are found to agree well with the predicted asymmetries.

Vasyliunas, V. M.; Dessler, A. J.

1981-01-01

423

Our Planetary System Earth, as viewed by the Voyager spacecraft  

E-print Network

s surface Probes or Landers · Land on surface of another world · Explore surface in detail Sample Return Missions · Land on surface of another world · Gather samples · Spacecraft designed to blast off other world about a world like our Earth by studying it in context with other worlds in the solar system. · Stay

Crenshaw, Michael

424

Scanning Probe Microscopy  

NSDL National Science Digital Library

Published by the National Nanotechnology Infrastructure Network, this hour-long activity has students "simulate the function of a scanning probe microscope" by creating their own scanning probe microscope (SPM) boxes. The Teacher's Guide contains everything the instructor needs to carry out the lesson: goals and objectives, advanced preparation notes, safety considerations, materials, questions, and even variations for different classrooms. The Student Worksheet walks students through the activity by having them begin by making a prediction, giving the procedures, providing space to record observations, and asking open questions for students to respond to. This is a ready-to-use activity for classrooms looking to explore nanotechnology and scanning probe microscopes.

2009-04-14

425

A numerical study of the evolution of the solar wind from Ulysses to Voyager 2  

Microsoft Academic Search

. Voyager 2 continues to explore the outer heliosphere as Ulysses studiesthe latitudinal dependence of the solar wind. During the year 1991 these spacecraft werewithin 2#latitude and their radial separation was larger than 30 AU. This alignmentpresents a good opportunity to investigate the evolution of the solar wind and# inparticular# the e#ect of pickup ions# which are an important component

C. Wang; J. D. Richardson; J. T. Gosling

2000-01-01

426

Documentation for the machine-readable version of the lick Saturn-Voyager Reference Star Catalogue  

Microsoft Academic Search

The machine-readable version of the catalog is described. The catalog was prepared in order to determine accurate equatorial coordinates for reference stars in a band of sky against which cameras of the Voyager spacecraft were aligned for observations in the region of Saturn during the flyby. Tape contents and characteristics are described and a sample listing presented.

W. H. Warren Jr.

1982-01-01

427

Infrared polar brightening on Jupiter. III. Spectrometry from the Voyager 1 IRIS experiment  

Microsoft Academic Search

Spectra from the Voyager 1 IRIS experiment confirm the existence of enhanced infrared emission near Jupiter's north magnetic pole in March 1979. The spectral characteristics of the enhanced emission are consistent with a Planck source function. A temperature-pressure profile is derived for the region near the north magnetic pole, from which quantitative abundance estimates of minor species are made. Some

S. J. Kim; J. Caldwell; A. R. Rivolo; R. Wagener; G. S. Orton

1985-01-01

428

Voyager observations of the interaction of the heliosphere with the interstellar medium  

PubMed Central

This paper provides a brief review and update on the Voyager observations of the interaction of the heliosphere with the interstellar medium. Voyager has found many surprises: (1) a new energetic particle component which is accelerated at the termination shock (TS) and leaks into the outer heliosphere forming a foreshock region; (2) a termination shock which is modulated by energetic particles and which transfers most of the solar wind flow energy to the pickup ions (not the thermal ions); (3) the heliosphere is asymmetric; (4) the TS does not accelerate anomalous cosmic rays at the Voyager locations; and (5) the plasma flow in the Voyagers 1 (V1) and 2 (V2) directions are very different. At V1 the flow was small after the TS and has recently slowed to near zero, whereas at V2 the speed has remained constant while the flow direction has turned tailward. V1 may have entered an extended boundary region in front of the heliopause (HP) in 2010 in which the plasma flow speeds are near zero.

Richardson, John D.

2012-01-01

429

Micron-sized particle impacts detected near Uranus by the Voyager 2 plasma wave instrument  

Microsoft Academic Search

During the Voyager 2 flyby of Uranus the plasma wave and radio astronomy instruments detected a region of impulsive noise near the equatorial plane. This noise is believed to be caused by micron-sized particles hitting the spacecraft. Analysis of various coupling mechanisms shows that when a dust particle hits the spacecraft at a high velocity, the particle is instantly vaporized

D. A. Gurnett; W. S. Kurth; K. L. Scarf; J. A. Burns; J. N. Cuzzi

1987-01-01

430

The Voyage of the Beagle: Field Work Lessons from Charles Darwin.  

ERIC Educational Resources Information Center

Analyzes Charles Darwin's letters to his family during his voyage on H.M.S. Beagle. Relates the information to the development of Darwin's professional identity and the degree to which the concepts, field methods, and research methods revealed in Darwin's personal correspondence are useful to students of educational administration. (MD)

Smith, Louis M.

1987-01-01

431

Robert J. Richards What if Charles Darwin, during the Beagle voyage, had been swept  

E-print Network

Robert J. Richards What if Charles Darwin, during the Beagle voyage, had been swept overboard a counterfactual history in his provocative new book Darwin Deleted. He intends by this history principally "to undermine the claim that the theory of natural selection inspired the various forms of social Darwinism" (6

Richards, Robert J.

432

Electron densities in Jupiter's outer magnetosphere determined from Voyager 1 and 2 plasma wave spectra  

E-print Network

Electron densities in Jupiter's outer magnetosphere determined from Voyager 1 and 2 plasma wave] This paper presents an electron plasma density data set for Jupiter's outer magnetosphere derived from high of $100 Hz or better, the density measurements are among the most accurate for Jupiter's magnetosphere

Santolik, Ondrej

433

Integration of speech recognition and natural language processing in the MIT VOYAGER system  

Microsoft Academic Search

The MIT VOYAGER speech understanding system is an urban exploration and navigation system that interacts with the user through spoken dialogue, text, and graphics. The authors describe recent attempts at improving the integration between the speech recognition and natural language components. They used the generation capability of the natural language component to produce a word-pair language model to constrain the

Victor Zue; James Glass; David Goodine; Hong Leung; Michael Phillips; Joseph Polifroni; S. Seneff

1991-01-01

434

Voyager spectra of density turbulence from 1 AU to the outer heliosphere  

Microsoft Academic Search

Power spectral analyses of the plasma density measured by the Voyager 2 spacecraft are used to investigate the spectral characteristics and fluctuation level of density turbulence from 1 to 60 AU, corresponding to the period 1977 to 1999. Only periods without clear discontinuities, with less than 10% missing data, and at least 256 samples are selected, strongly limiting the number

Beau R. Bellamy; Iver H. Cairns; C. W. Smith

2005-01-01

435

A new look at the Saturn system - The Voyager 2 images  

Microsoft Academic Search

Images of the Saturn system acquired by Voyager 2 in its encounter in August 1981 are presented and information gained from the imagery on the atmosphere, satellites, and rings of Saturn is discussed. The images have shown the Saturn atmosphere to contain persistent oval clouds similar to those of Jupiter, and small irregular features indicative of a pattern of zonal

B. A. Smith; L. Soderblom; R. M. Batson; P. M. Bridges; J. L. Inge; H. Masursky; E. Shoemaker; R. F. Beebe; J. Boyce; G. Briggs; A. Bunker; S. A. Collins; C. J. HANSEN; T. V. Johnson; J. L. Mitchell; R. J. Terrile; A. F. Cook; J. N. Cuzzi; J. B. Pollack; G. E. Danielson; A. P. Ingersoll; M. E. Davies; G. E. Hunt; D. Morrison; T. Owen; C. Sagan; J. Veverka; R. Strom; V. E. Suomi

1982-01-01

436

New perspectives on Titan's upper atmosphere from a reanalysis of the Voyager 1 UVS solar occultations  

Microsoft Academic Search

We have reanalyzed the Voyager 1 UVS solar occultations by Titan to expand upon previous analyses and to resolve inconsistencies that have been noted in the scientific literature. To do so, we have developed a detailed model of the UVS detector and improved both the data reduction methods and retrieval techniques. In comparison to the values previously determined by Smith et

Ronald J. Vervack Jr.; Bill R. Sandel; Darrell F. Strobel

2004-01-01

437

Interacting with the Disappearing Computer: Evaluation of the Voyager Development Framework  

Microsoft Academic Search

We have developed a programming framework named Voyager, for making interactive applications with dynamically composed User Interfaces, consisting of remote input \\/ output elements hosted by environment devices. This framework reflects our perspective of the disappearing computer concept as an infrastructure enabling mobile uses to exploit on the fly any available proximate devices for the purposes of interaction. The evaluation

Anthony Savidis; Constantine Stephanidis

438

Direct measurements of the polarization of terrestrial kilometric radiation from Voyagers 1 and 2  

NASA Technical Reports Server (NTRS)

Terrestrial radiation measurements obtained with planetary radio astronomy experiments on Voyager-1 and 2 during the early portions of each flight show the signals to be predominantly left-hand circularly polarized. Since these emissions were most probably generated above the Northern Hemisphere auroral zone, it is concluded that the radiation is emitted primarily in the extraordinary mode.

Kaiser, M. L.; Alexander, J. K.; Riddle, A. C.; Pearce, J. B.; Warwick, J. W.

1978-01-01

439

Clouds, Bands And Discrete Features On Saturn: Comparisons Between Cassini And Voyager  

NASA Astrophysics Data System (ADS)

We examine new images returned from Cassini spacecraft's ISS camera to analyze tropospheric cloud morphology of Saturn. We compare our findings to Voyager 2 observations to search for changes in global cloud morphology. Images were acquired around the equinox and our datasets provide near-global coverage in multiple wavelength bands. We find that the clouds exhibit the highest contrasts in infrared continuum centered at 752 & 939 nm (CB2 & CB3 filters, respectively) and 727 & 890 nm methane bands (MT2 & MT3). We compare the present day location of Saturn's bands to those of the Voyager era. We reconfirm multiple features that were previously found in Voyager's visible and Cassini infrared images in the northern hemisphere. First, we examine the Ribbon wave found by the Voyager missions (Sromovsky et al. 1983; Godfrey and Moore, 1986) at multiple wavelength bands. Next, we examine the behavior of a dark vortex that exhibits many similarities to the vortex labeled by Sromovsky et al. as Brown Spot 1. Our data also shows a visible-light counterpart to the String of Pearls feature, which appeared as a series of planet encircling bright spots in 5-micron VIMS images (Momary et al. 2006), suggesting that they are cloud clearings. Our images confirm that there are indeed a string of dark cloud-free spots in the region, which enable us to study their dynamics and compare our results to the VIMS measurements by Choi et al (2009). We also compare the appearance of the north-polar hexagon at multiple wavelengths. Our data also provides good coverage in the southern hemisphere, and we compare our results to Voyager images in 1980-81 and images acquired during the early phase of Cassini mission. Supported by the Cassini Project and a Summer Undergraduate Research Fellowship from Caltech.

Muro, Gabriel; Sayanagi, K. M.; Ewald, S. P.; Ingersoll, A. P.

2010-10-01

440

EMISSION-LINE GALAXIES FROM THE HUBBLE SPACE TELESCOPE PROBING EVOLUTION AND REIONIZATION SPECTROSCOPICALLY (PEARS) GRISM SURVEY. II. THE COMPLETE SAMPLE  

SciTech Connect

We present a full analysis of the Probing Evolution And Reionization Spectroscopically (PEARS) slitess grism spectroscopic data obtained with the Advanced Camera for Surveys on board Hubble Space Telescope. PEARS covers fields within both the Great Observatories Origins Deep Survey (GOODS) North and South fields, making it ideal as a random survey of galaxies, as well as the availability of a wide variety of ancillary observations complemented by the spectroscopic results. Using the PEARS data, we are able to identify star-forming galaxies (SFGs) within the redshift volume 0 < z < 1.5. Star-forming regions in the PEARS survey are pinpointed independently of the host galaxy. This method allows us to detect the presence of multiple emission-line regions (ELRs) within a single galaxy. We identified a total of 1162 H{alpha}, [O III], and/or [O II] emission lines in the PEARS sample of 906 galaxies to a limiting flux of {approx}10{sup -18} erg s{sup -1} cm{sup -2}. The ELRs have also been compared to the properties of the host galaxy, including morphology, luminosity, and mass. From this analysis, we find three key results: (1) the computed line luminosities show evidence of a flattening in the luminosity function with increasing redshift; (2) the star-forming systems show evidence of complex morphologies with star formation occurring predominantly within one effective (half-light) radius. However, the morphologies show no correlation with host stellar mass. (3) Also, the number density of SFGs with M{sub *} {>=} 10{sup 9} M{sub Sun} decreases by an order of magnitude at z {<=} 0.5 relative to the number at 0.5 < z < 0.9, supporting the argument of galaxy downsizing.

Pirzkal, Nor; Rothberg, Barry; Ly, Chun; Grogin, Norman A.; Dahlen, Tomas; Noeske, Kai G.; Bellini, Andrea [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21210 (United States); Malhotra, Sangeeta; Rhoads, James E.; Cohen, Seth H.; Mechtley, Matthew; Windhorst, Rogier A. [School of Earth And Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States); Meurer, Gerhardt R. [International Centre for Radio Astronomy Research, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia); Walsh, Jeremy R. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany); Hathi, Nimish P. [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Holwerda, Benne W. [ESA-ESTEC, Keplerlaan 1, 2200 AG, Noordwijk (Netherlands); Straughn, Amber N. [Astrophysics Science Division, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States)

2013-07-20

441

Low-Energy Charged Particles in Saturn's Magnetosphere: Results from Voyager 1.  

PubMed

The low-energy charged particle instrument on Voyager 1 measured low-energy electrons and ions (energies >/= 26 and >/= 40 kiloelectron volts, respectively) in Saturn's magnetosphere. The first-order ion anisotropies on the dayside are generally in the corotation direction with the amplitude decreasing with decreasing distance to the planet. The ion pitch-angle distributions generally peak at 90 degrees , whereas the electron distributions tend to have field-aligned bidirectional maxima outside the L shell of Rhea. A large decrease in particle fluxes is seen near the L shell of Titan, while selective particle absorption (least affecting the lowest energy ions) is observed at the L shells of Rhea, Dione, and Tethys. The phase space density of ions with values of the first invariant in the range approximately 300 to 1000 million electron volts per gauss is consistent with a source in the outer magnetosphere. The ion population at higher energies (>/= 200 kiloelectron volts per nucleon) consists primarily of protons, molecular hydrogen, and helium. Spectra of all ion species exhibit an energy cutoff at energies >/= 2 million electron volts. The proton-to-helium ratio at equal energy per nucleon is larger (up to approximately 5 x 10(3)) than seen in other magnetospheres and is consistent with a local (nonsolar wind) proton source. In contrast to the magnetospheres of Jupiter and Earth, there are no lobe regions essentially devoid of particles in Saturn's nighttime magnetosphere. Electron pitch-angle distributions are generally bidirectional andfield-aligned, indicating closed field lines at high latitudes. Ions in this region are generally moving toward Saturn, while in the magnetosheath they exhibit strong antisunward streaming which is inconsistent with purely convective flows. Fluxes of magnetospheric ions downstream from the bow shock are present over distances >/= 200 Saturn radii from the planet. Novel features identified in the Saturnian magnetosphere include a mantle of low-energy particles extending inward from the dayside magnetopause to approximately 17 Saturn radii, at least two intensity dropouts occurring approximately 11 hours apart in the nighttime magnetosphere, and a pervasive population of energetic molecular hydrogen. PMID:17783834

Krimigis, S M; Armstrong, T P; Axford, W I; Bostrom, C O; Gloeckler, G; Keath, E P; Lanzerotti, L J; Carbary, J F; Hamilton, D C; Roelof, E C

1981-04-10

442

Jules Verne Voyager, Jr: An Interactive Map Tool for Teaching Plate Tectonics  

NASA Astrophysics Data System (ADS)

We present an interactive, web-based map utility that can make new geological and geophysical results accessible to a large number and variety of users. The tool provides a user-friendly interface that allows users to access a variety of maps, satellite images, and geophysical data at a range of spatial scales. The map tool, dubbed 'Jules Verne Voyager, Jr.', allows users to interactively create maps of a variety of study areas around the world. The utility was developed in collaboration with the UNAVCO Consortium for study of global-scale tectonic processes. Users can choose from a variety of base maps (including "Face of the Earth" and "Earth at Night" satellite imagery mosaics, global topography, geoid, sea-floor age, strain rate and seismic hazard maps, and others), add a number of geographic and geophysical overlays (coastlines, political boundaries, rivers and lakes, earthquake and volcano locations, stress axes, etc.), and then superimpose both observed and model velocity vectors representing a compilation of 2933 GPS geodetic measurements from around the world. A remarkable characteristic of the geodetic compilation is that users can select from some 21 plates' frames of reference, allowing a visual representation of both 'absolute' plate motion (in a no-net rotation reference frame) and relative motion along all of the world's plate boundaries. The tool allows users to zoom among at least three map scales. The map tool can be viewed at http://jules.unavco.org/VoyagerJr/Earth. A more detailed version of the map utility, developed in conjunction with the EarthScope initiative, focuses on North America geodynamics, and provides more detailed geophysical and geographic information for the United States, Canada, and Mexico. The ‘EarthScope Voyager’ can be accessed at http://jules.unavco.org/VoyagerJr/EarthScope. Because the system uses pre-constructed gif images and overlays, the system can rapidly create and display maps to a large number of users simultaneously and does not require any special software installation on users' systems. In addition, a javascript-based educational interface, dubbed "Exploring our Dynamic Planet", incorporates the map tool, explanatory material, background scientific material, and curricular activities that encourage users to explore Earth processes using the Jules Verne Voyager, Jr. tool. Exploring our Dynamic Planet can be viewed at http://www.dpc.ucar.edu/VoyagerJr/. Because of its flexibility, the map utilities can be used for hands-on exercises exploring plate interaction in a range of academic settings, from high school science classes to entry-level undergraduate to graduate-level tectonics courses.

Hamburger, M. W.; Meertens, C. M.

2010-12-01

443

Space Missions  

NSDL National Science Digital Library

With three levels to choose from on each page - beginner, intermediate or advanced - this site provides in formation on past and current exploration ideas and achievements. The advances science has made in the space exploration area, such as having a permanent space station in space and the hundreds of probes, satellite, and space shuttles that have been launched. Advanced telescopes have given scientists the opportunity to see far beyond we ever imagined, and new explorations are found every day. Also featured are details about the International space station and what kinds of experiments scientists do in outer space.

Russell, Randy

2004-05-10

444

Logic Probes  

NSDL National Science Digital Library

This brief interactive activity, by the Electromechanical Digital Library and Wisconsin Technical College System faculty, introduces Logic Probes. There is an overview which illustrates the probe's application and operation and how to operate a logic probe in multifamily use, steady states, and changing states. There is also a set of three review questions for students to answer at the end. This is an excellent resource, as are the others in this digital library, for reviewing fundamental concepts for electromechanical devices, systems, and applications.

Bartelt, Terry L.

2009-05-07

445

Voyagers and voyeurs: supporting asynchronous collaborative information visualization  

Microsoft Academic Search

This paper describes mechanisms for asynchronous collaboration in the context of information visualization, recasting visualizations as not just analytic tools, but social spaces. We contribute the design and implementation of sense.us, a web site supporting asynchronous collaboration across a variety of visualization types. The site supports view sharing, discussion, graphical annotation, and social navigation and includes novel interaction elements. We

Jeffrey Heer; Fernanda B. Viégas; Martin Wattenberg

2007-01-01

446

Cosmic ray modulation and the distant heliospheric magnetic field: Voyager 1 and 2 observations from 1986 to 1989  

Microsoft Academic Search

The changes in the cosmic ray intensity >70 MeV\\/nucleon observed by Voyager I (termed VI) near 30[degrees] heliographic latitude and by Voyager 2 (termed V2) near O[degrees] heliographic latitude from 1986 to 1990 were closely related to the large-scale fluctuations in the magnetic field strength at VI and V2, respectively. The decreases in the cosmic ray intensity observed by VI

L. F. Burlaga; F. B. McDonald; N. F. Ness

1993-01-01

447

Voyager 2 ultraviolet spectrometer solar occultations at Neptune - Constraints on the abundance of methane in the stratosphere  

NASA Technical Reports Server (NTRS)

The study compares Voyager 2 ultraviolet spectrometer (UVS) solar occultation lightcurves at wavelengths 125-138 nm acquired during the Neptune encounter with 1D methane photochemical transport models. For the p-T models under consideration, acceptable fits to the UVS lightcurves are obtained with eddy mixing coefficient values (K sub 1/2) near the half-light altitudes of 2-15 x 10 exp 6 sq cm/s (ingress) and 4-35 x 10 exp 6 sq cm/s (egress) and lower stratospheric methane mixing ratio values of 5-100 x 10 exp -5. For the nominal p-T models and a criterion based on replicating the spacing in altitude of the 125-138 nm UVS lightcurves, K sub 1/2 values of 10 exp 7 sq cm/s (ingress) and 1-2 x 10 exp 7 sq cm/s (egress) and methane mixing ratios of about 0.0004 (ingress and egress) are indicated.

Bishop, James; Atreya, Sushil K.; Romani, Paul N.; Sandel, Bill R.; Herbert, Floyd

1992-01-01

448

IUE and Voyager Observations of the Unusual Cataclysmic Variable S193  

NASA Astrophysics Data System (ADS)

UV observations of S193 were obtained with Voyager and the IUE satellite during both high and low states of this unusual object. Voyager only detected the source during the high state, where the continuum looks similar to the novalike IX Vela and dwarf novae at outburst. The IUE spectra at the high state show deep absorption lines, but the line ratios are not typical of disk cataclysmic variables at outburst. They are most similar to V795 Her and the SW Sex star PG0859+415. At the low state, only CIV and MgII are in emission, while the deep absorptions at SiIII and NV persist. The spectra at this state are most similar to the intermediate polar candidate H0551-819. The UV observations of S193 provide further circumstantial evidence for the existence of a disk and a magnetic white dwarf in an intermediate polar system.

Szkody, Paula; Garnavich, Peter; Holberg, Jay; Silber, Andrew; Pastwick, Lora

1997-06-01

449

Jupiter Data Analysis Program: Analysis of Voyager wideband plasma wave observations  

NASA Technical Reports Server (NTRS)

Voyager plasma wave wideband frames from the Jovian encounters are analyzed. The 511 frames which were analyzed were chosen on the basis of low-rate spectrum analyzer data from the plasma wave receiver. These frames were obtained in regions and during times of various types of plasma or radio wave activity as determined by the low-rate, low-resolution data and were processed in order to provide high resolution measurements of the plasma wave spectrum for use in the study of a number of outstanding problems. Chorus emissions at Jupiter were analyzed. The detailed temporal and spectral form of the very complex chorus emissions near L = 8 on the Voyager 1 inbound passage was compared to both terrestrial chorus emissions as well as to the theory which was developed to explain the terrestrial waves.

Kurth, W. S.

1983-01-01

450

Voyager 2 Observations of Plasmas and Flows out to 104 AU  

NASA Astrophysics Data System (ADS)

Voyager 2 has crossed through 20 AU of the heliosheath; assuming the same heliosheath thickness as at Voyager 1, it is now two-thirds of the way to the heliopause. The plasma data are generally of good quality, although the increasing flow angle of the plasma makes analysis more difficult. The average plasma speed has remained constant but the flow angles have increased to almost 60° in the RT plane and to almost 30° in the RN plane. The average density and thermal speed have been constant since a density increase observed in 2011. Comparison of V2 plasma flows derived from plasma science experiment (PLS) data and Low Energy Charged Particle (LECP) proton anisotropies give good agreement except when heavy ion contributions or non-convective proton anisotropies are observed in the LECP data.

Richardson, J. D.; Decker, R. B.

2014-09-01

451

SkyServer Voyages: Next-Generation Educational Activities using the Sloan Digital Sky Survey  

NASA Astrophysics Data System (ADS)

The Sloan Digital Sky Survey (SDSS) “SkyServer” has long included online educational materials designed to enable students and the public to discover the fundamentals of modern astronomy using real observations from the SDSS database. Efforts are now being made to update and expand these activities to reflect new data from additional generations of the survey (e.g., SDSS-III), advances in web capabilities and changing trends in science education. The new site, “SkyServer Voyages”, aims to provide access to quality astronomy, astrophysics and engineering materials to educators with a particular focus on those seeking to implement the new Next Generation Science Standards (NGSS) in the US. We provide an overview of the design and development of Skyserver Voyages and discuss ways to apply this resource at the K-12 and university levels.

Meredith, Kate; Raddick, J.; Lundgren, B.

2014-01-01

452

Relating IBEX and Voyager Data through Global Modeling of the Heliospheric Interface  

NASA Astrophysics Data System (ADS)

The combination of the Interstellar Boundary Explorer (IBEX) all-sky maps of the energetic neutral atom fluxes with the Voyager in situ measurements gives us a unique opportunity to learn more about the physics governing the solar wind (SW) interaction with the local interstellar medium (LISM). Moreover, since the position of the ribbon of an enhanced ENA flux in the sky strongly depends on the LISM properties, we are able to constrain those by comparing numerical simulations with the IBEX observations. In this paper, we discuss the current status of the Huntsville model of the SW-LISM interaction, compare numerical results with the IBEX and Voyager observations, and discuss the importance of taking into account time-dependent phenomena, particularly the solar cycle effects.

Pogorelov, N. V.; Heerikhuisen, J.; Borovikov, S. N.; Zank, G. P.; Ebert, R. W.; McComas, D. J.; Richardson, J. D.; Suess, S. T.

2010-12-01

453

Absolute far-ultraviolet spectrophotometry of hot subluminous stars from Voyager  

NASA Technical Reports Server (NTRS)

Observations, obtained with the Voyager ultraviolet spectrometers, are presented of absolute fluxes for two well-known hot subluminous stars: BD + 28 deg 4211, an sdO, and G191 - B2B, a hot DA white dwarf. Complete absolute energy distributions for these two stars, from the Lyman limit at 912 A to 1 micron, are given. For BD + 28 deg 4211, a single power law closely represents the entire observed energy distribution. For G191 - B2B, a pure hydrogen model atmosphere provides an excellent match to the entire absolute energy distribution. Voyager absolute fluxes are discussed in relation to those reported from various sounding rocket experiments, including a recent rocket observation of BD + 28 deg 4211.

Holberg, J. B.; Ali, B.; Carone, T. E.; Polidan, R. S.

1991-01-01

454

A new spectrum of Triton near the time of the Voyager encounter  

NASA Technical Reports Server (NTRS)

A 5200-10,000 A spectrum of Triton that was telescopically obtained during the summer of 1989, just before the Voyager II encounter with the Neptune system, exhibits a measurable 8900 A CH4 ice absorption band. A combination of these data with those of Voyager indicates that the absorption is caused solely by Triton surface CH4 ice. A Hapke-type model for the Triton spectrum (1) sets a 20-micron lower limit on the CH4 ice's mean grain size (although it is suspected that actual grain size is closer to 100 microns), and (2) indicates that CH4 ice is widely distributed on the southern-hemisphere surface of Triton.

Grundy, William M.; Fink, Uwe

1991-01-01

455

Energetic Particle Composition and Anisotropy in the Termination Foreshock and Heliosheath: Voyagers 1 and 2 Compared  

NASA Astrophysics Data System (ADS)

Voyager 1 (V1) traveled from the termination foreshock (TFS) into the heliosheath (HS) by crossing the termination shock (TS) on 16 December 2004. Likewise, Voyager 2 (V2) made this transition on 1 September 2007. Now with two encounters at very different regions of the TS, we will compare the anisotropy and composition of 30 keV- -1 MeV and 1--50 MeV/nuc particles, seeking the common and peculiar features of the TFS and HS regions at the two Voyager locations, ~100AU apart. The Voyager 1 spectra in both the TFS and HS are organized by total energy. The anisotropy in the TFS is however velocity dependent and directed along -T (in spacecraft RTN- coordinates) while, by contrast, during a rare period of non-negligible anisotropy in the HS from 6--26 March 2005, the anisotropy was organized by total energy, peaked at ~20 MeV, and directed in the +T direction. This may indicate that the TFS is nearly scatter free while the HS is a high-scattering region at V1. At V2 from January to August 2007, before the TS crossing, it appears that below ~0.5-MeV the anisotropies are predominantly in the +T direction and above they are in the -T direction. We are so far unable to distinguish between total energy and velocity dependence in the V2 data, but the reversal of the anisotropy at a particular energy may be related to the reflection of upstream and transmission of downstream particles. We will continue our analysis of the V2 data and report on the comparison between the anisotropies and composition at the positions of V1 and V2.

Hill, M. E.; Decker, R. B.; Hamilton, D. C.; Krimigis, S. M.; Roelof, E. C.

2008-05-01

456

Zonal mean properties of Jupiter's upper troposphere from Voyager infrared observations  

NASA Astrophysics Data System (ADS)

Voyager IRIS spectra of Jupiter are used to derive zonal averages for 270- and 150-mb temperatures, as well as optical depths through the troposphere at two temperatures, ammonia concentrations near the 680-mb level, and the parahydrogen fraction near the 270-mb level. Simple modeling of an axisymmetric circulation incorporating the linear damping of perturbations from a uniform state for both winds and temperature yields results that are consistent with observed thermal wind shears and with the vertical motion field.

Gierasch, P. J.; Magalhaes, J. A.; Conrath, B. J.

1986-09-01

457

The Gulf Stream Voyage: Using Real Time Data in the Classroom  

NSDL National Science Digital Library

This paper describes the Gulf Stream Voyage, an Internet-based multidisciplinary project which utilizes both real time data and primary source materials to help guide students to discover the science and history of the Gulf Stream. There are several advantages of using real time data in the classroom, including: the infusion of inquiry-based learning; fostering problem solving skills; addressing several learning styles; and student relevance.

Hotaling, Liesl

458

A Survey of the Plasma Electron Environment of Jupiter: A View From Voyager  

Microsoft Academic Search

A survey of the plasma environment within Jupiter's bow shock is presented in terms of the in situ, calibrated electron plasma measurements made between 10 eV and 5.95 keV by the Voyager Plasma Science Experiment (PLS). These measurements have been analyzed and corrected for spacecraft potential variations; the data have been reduced to nearly model independent macroscopic parameters of the

J. D. Scudder; E. C. Sittler; H. S. Bridge

1981-01-01

459

From Alexander von Humboldt to Frederic Edwin Church: Voyages of Scientific Exploration and Creativity  

E-print Network

.......................................................................................................13 „From Humboldt to F. E. Church“ (F. Baron) 2HiN VI, 10 (2005) Humboldt im Netz From Alexander von Humboldt to Frederic Edwin Church: Voyages of Scientific Exploration and Creativity Frank Baron Abstract Stephen Jay Gould wrote recently that „when.... Zusammenfassung Der amerikanische Wissenschaftshistoriker Stephen Jay Gould stellte fest, daß Alexander von Humboldt um die Mitte des neunzehnten Jahrhunderts vielleicht der berühmteste und einflußreichste Intellektuelle gewesen sei. Zu diesem Zeitpunkt bietet...

Baron, Frank

2005-01-01

460

Some dynamical properties of vortex streets in Saturn's atmosphere from analyses of Voyager images  

NASA Technical Reports Server (NTRS)

The first observations of a vortex street in an atmosphere other than that of the earth are presented, made from a sequence of images of Saturn taken by Voyager 2 in August 1981. The analysis of these images shows that the feature sits at the maximum of the westward jet and suggests that it may be produced by material rising up from below the level of the visible clouds.

Godfrey, D.; Hunt, G. E.; Suomi, V. E.

1983-01-01

461

Properties of scatterers in the troposphere and lower stratosphere of Uranus based on Voyager imaging data  

Microsoft Academic Search

Scalar and vector radiative transfer and microphysical models are presently constructed from photometrically and geometrically corrected Voyager images of Uranus defining spatially-resolved intensities over a range of phase angles for two latitude bands. The methane ice cloud occupying 1.2-1.3 bar is of 0.7 optical depth at 22.5 deg S, rising to 2.4 at 65 deg S; the volume absorption coefficient

K. Rages; J. B. Pollack; M. G. Tomasko; L. R. Doose

1991-01-01

462

A Study of Saturn's E-Ring Particles Using the Voyager 1 Plasma Wave Instrument  

NASA Technical Reports Server (NTRS)

The flyby of Voyager 1 at Saturn resulted in the detection of a large variety of plasma waves, e.g., chorus, hiss, and electron cyclotron harmonics. Just before the outbound equator crossing, at about 6.1 R(sub s), the Voyager 1 plasma wave instrument detected a strong, well-defined low-frequency enhancement. Initially it was suggested that plasma waves might be responsible for the spectral feature but more recently dust was suggested as at least a partial contributor to the enhancement. In this report we present evidence which supports the conclusion that dust contributes to the low-frequency enhancement. A new method has been used to derive the dust impact rate. The method relies mainly on the 16-channel spectrum analyzer data. The few wide band waveform observations available (which have been used to study dust impacts during the Voyager 2 ring plane crossing) were useful for calibrating the impact rate from the spectrum analyzer data. The mass and, hence, the size of the dust particles were also obtained by analyzing the response of the plasma wave spectrum analyzer. The results show that the region sampled by Voyager 1 is populated by dust particles that have rms masses of up to few times 10(exp -11) g and sizes of up to a few microns. The dust particle number density is on the order of 10(exp -3) m(exp 3). The optical depth of the region sampled by the spacecraft is 1.04 x 10(exp -6). The particle population is centered about 2500 km south of the equatorial plane and has a north-south thickness of about 4000 km. Possible sources of these particles are the moons Enceladus and Tethys whose orbits lie within the E-ring radial extent. These results are in reasonable agreement with photometric studies and numerical simulations.

Tsintikidis, D.; Kurth, W. S.; Gurnett, D. A.; Barbosa, D. D.

1993-01-01

463

Survey of low energy plasma electrons in Saturn's magnetosphere: Voyagers 1 and 2  

Microsoft Academic Search

The low energy plasma electron environment within Saturn's magnetosphere was surveyed by the Plasma Science Experiment (PLS) during the Voyager encounters with Saturn. Over the full energy range of the PLS instrument (10 eV to 6 keV) the electron distribution functions are clearly non-Maxwellian in character. They are composed of a cold (thermal) component with Maxwellian shape and a hot

E. C. Jr. Sittler; K. W. Ogilvie; J. D. Scudder

1983-01-01

464

Io’s Hot Plasma Torus—A Synoptic View from Voyager  

Microsoft Academic Search

A study of the morphology of Io's hot plasma torus has encompassed hundreds of Voyager UVS measurements of torus intensity. The long-term average stateøof the torus can be characterized by an axial asymmetry in the brightness of the prominent SIII 685-A feature manifested as an enhancement in brightness whose peak is fixed near 1900 local time. No long-term correlation of

B. R. Sandel; A. L. Broadfoot

1982-01-01

465

Interplanetary Lyman ? Observations: Intensities from Voyagers and Line Profiles from HST/STIS  

NASA Astrophysics Data System (ADS)

We present an analysis of Voyager UVS data obtained between 1993 and mid-2007. These data are used to study the interplanetary background and the hydrogen number density in the outer heliosphere. Two types of observations are studied, first the heliospheric scans performed until 2003 and then the fixed line of sight observations, close to the upwind direction, which are still performed at the end of 2007.

Quémerais, Eric; Lallement, Rosine; Sandel, Bill R.; Clarke, John T.

466

Heliospheric magnetic field strength out to 66 AU: Voyager 1, 1978–1996  

Microsoft Academic Search

We discuss Voyager 1 (V1) observations of the heliospheric magnetic field strength from 1978 through 1996. During this period the distance of V1 from the Sun increased from 3 AU to 66 AU and its heliographic latitude increased from 5øS to 33øN. The magnetic field strength profile observed by V1 is consistent with Parker's spiral field model when one considers

L. F. Burlaga; N. F. Ness; Y.-M. Wang; N. R. Sheeley

1998-01-01

467

Heliospheric magnetic field strength out to 66 AU: Voyager 1, 1978-1996  

Microsoft Academic Search

We discuss Voyager 1 (V1) observations of the heliospheric magnetic field strength from 1978 through 1996. During this period the distance of V1 from the Sun increased from ~3 AU to 66 AU and its heliographic latitude increased from ~5°S to 33°N. The magnetic field strength profile observed by V1 is consistent with Parker's spiral field model when one considers

L. F. Burlaga; N. F. Ness; Y.-M. Wang; N. R. Sheeley

1998-01-01

468

Jupiter's magnetopause, bow shock, and 10-hour modulated magnetosheath: Voyagers 1 and 2  

NASA Technical Reports Server (NTRS)

Fine scale magnetic field data from the Voyager 1 and 2 magnetopause and bow shock crossings at Jupiter were analyzed. Explicit models of the dawnside magnetopause and bow shock in Jupiter's orbital plane employ an axisymmetric parabola and hyperbola, respectively, and are determined separately for the encounters. A new phenomenon was discovered in the magnetosheath. It is manifested as (5 or) 10 hour quasi-periodic modulation of the direction of the magnetic field in the outbound magnetosheath, predominantly in the northward (N) and southward (S) directions. It was seen to occur during both encounters and appears most evident in Voyager 2 outbound observations, probably due to the extreme tailward extent of the Voyager 2 trajectory through the magnetosheath. The durations of the N to and from S transitions range from tens of minutes to approximately 3 hours. The directional variation of the field during these transitions is fairly well restricted to a plane parallel to the local model magnetopause location. These signatures may be due to magnetosheath field line draping modulated by the large scale motion of the magnetospheric plasma disk.

Lepping, R. P.; Burlaga, L. F.; Klein, L. W.

1980-01-01

469

Voyager observations of O(+6) and other minor ions in the solar wind  

NASA Technical Reports Server (NTRS)

The plasma science (PLS) experiments on the Voyager 1 and 2 spacecraft began making measurements of the solar wind shortly after the two launches in the fall of 1977. In reviewing the data obtained prior to the Jupiter encounters in 1979, we have found that the large dynamic range of the PLS instrument generally allows a clean separation of signatures of minor ions (about 2.5% of the time) during a single instrument scan in energy per charge. The minor ions, most notably O(+6), are well separated from the protons and alpha particles during times when the solar wind Mach number (ratio of streaming speed to thermal speed) is greater than approximately 15. During the Earth to Jupiter cruise we find that the average ratio of alpha particle number density to that of oxygen is 66 +/- 7 (Voyager 1) and 71 +/- 17 (Voyager 2). These values are consistent with the value 75 +/- 20 inferred from the Ion Composition Instrument on ISEE 3 during the period spanning 1978 and 1982. We have inferred an average coronal temperature of (1.7 +/- 0.1) x 10(exp 6) K based on the ratio of O(+7) to O(+6) number densities. Our observations cover a period of increasing solar activity. During this time we have found that the alpha particle to proton number density ratio is increasing with the solar cycle, the oxygen to proton ratio increases, and the alpha particle to oxygen ratio remains relatively constant in time.

Villanueva, Louis; Mcnutt, Ralph L., Jr.; Lazarus, Alan J.; Steinberg, John T.

1994-01-01

470

Antenna arraying performance for deep space telecommunications systems  

NASA Technical Reports Server (NTRS)

Antenna arraying is a crucial Deep Space Network technique in maximizing the science return of planetary and comet encounters. The equations which describe the total figure of merit for a multiple system of arrayed antennas are developed. An example is given for three Canberra DSN antennas and the Parkes 64-m antenna to be arrayed for the Voyager 2 Uranus flyby.

Stelzried, C. T.; Berman, A. L.; Noreen, G. K.

1983-01-01

471

Interagency arraying. [Voyager 2/Neptune telemetry and data reception  

NASA Technical Reports Server (NTRS)

Activities performed to match ground aperture requirements for the Neptune encounter in August 1989 with the expected capabilities of the JPL Deep Space Network (DSN) are discussed. Ground aperture requirements, DSN capabilities, and the capabilities of other agencies are reviewed. The design and configurations of the receiver subsystem, combiner subsystem, monitor and control subsystem, recording subsystem, and supporting subsystems are described. The implementation of the Very Large Array-Goldstone Telemetry Array is discussed, and the differences involved with the Parkes-Canberra Telemetry Array implementation are highlighted. The operational concept is addressed.

Cox, Henry G.

1987-01-01

472

Going from lectures to expeditions: Creating a virtual voyage in undergraduate ocean science education  

NASA Astrophysics Data System (ADS)

The WWW provides for new collaborations in distributed learning in higher education. The lead author has developed a highly successful online course at the undergraduate level with an enrollment of more than 300 non-science majors each year, We are currently initiating a new focus for the course by emphasizing sea-going research, primarily in the northeastern Pacific Ocean, through the development of a virtual oceanographic voyage over the WWW. The "virtual voyage" courseware combines elements of experiential learning with anytime, anywhere access of the WWW to stimulate inquiry-based learning in the ocean sciences. The first leg of the voyage is currently being synthesized from contemporary ocean research sponsored by a collaboration of U.S. government agencies, including NSF, NOAA, and the USGS. The initial portion of this effort involves transforming portions of USGS Circular 1198, Beyond the Golden Gate -- Oceanography, Geology, Biology, and Environmental Issues in the Gulf of the Farallones, into an interactive expedition by which students participate as scientists aboard a research vessel departing from San Francisco. Virtual experiments on the voyage are patterned after research cruises over the past decade in two national marine sanctuaries and include the technologies of data acquisition and data analysis, as well as providing insight into the methodologies of working marine scientists. Real-time data for monitoring the marine environment are embedded into several modules; for example, students will analyze data from offshore buoys and satellite imagery to assess ocean conditions prior to departing from port. Multibeam sonar is used to create seafloor maps near the Golden Gate Bridge and sediment cores provide evidence of sea-level change in the region. Environmental studies in the region include locating canisters of low-level radioactive waste and assessing potential sites for the disposal for dredged materials from the San Francisco Bay. Upon completion of these studies, the voyage turns northward to examine the seismic potential of the Cascadia subduction zone and hydrothermal vent communities on the Juan de Fuca Ridge. Although the project takes advantage of the natural interest of students in California through a geographic focus, it may also serve as a template for creating similar learning environments based elsewhere in the world.

Reed, D.; Garfield, N.; Locke, J.; Anglin, J.; Karl, H.; Edwards, B.

2003-04-01

473

Gravity Probe B Inspection  

NASA Technical Reports Server (NTRS)

The space vehicle Gravity Probe B (GP-B) is the relativity experiment developed at Stanford University to test two extraordinary predictions of Albert Einstein's general theory of relativity. The experiment will measure, very precisely, the expected tiny changes in the direction of the spin axes of four gyroscopes contained in an Earth-orbiting satellite at a 400-mile altitude. So free are the gyroscopes from disturbance that they will provide an almost perfect space-time reference system. They will measure how space and time are very slightly warped by the presence of the Earth, and, more profoundly, how the Earth's rotation very slightly drags space-time around with it. These effects, though small for the Earth, have far-reaching implications for the nature of matter and the structure of the Universe. GP-B is among the most thoroughly researched programs ever undertaken by NASA. This is the story of a scientific quest in which physicists and engineers have collaborated closely over many years. Inspired by their quest, they have invented a whole range of technologies that are already enlivening other branches of science and engineering. In this photograph, engineer Gary Reynolds is inspecting the inside of the probe neck during probe thermal repairs. GP-B is scheduled for launch in April 2004 and managed for NASA by the Marshall Space Flight Center. Development of the GP-B is the responsibility of Stanford University along with major subcontractor Lockheed Martin Corporation. (Image credit to Russ Leese, Gravity Probe B, Stanford University)

2000-01-01

474

Europe's First Moon Probe Enters Lunar Orbit  

NSDL National Science Digital Library

This web page provides milestones of the European Space Agency's first space probe to the moon. The ESA's ion driven SMART-1 probe entered lunar orbit on 2004 Nov 16 after an 80 million kilometer, 13 month journey. Mission and spacecraft details, as well as images, are provided.

475

Multispectral imaging probe  

DOEpatents

A multispectral imaging probe delivers a range of wavelengths of excitation light to a target and collects a range of expressed light wavelengths. The multispectral imaging probe is adapted for mobile use and use in confined spaces, and is sealed against the effects of hostile environments. The multispectral imaging probe comprises a housing that defines a sealed volume that is substantially sealed from the surrounding environment. A beam splitting device mounts within the sealed volume. Excitation light is directed to the beam splitting device, which directs the excitation light to a target. Expressed light from the target reaches the beam splitting device along a path coaxial with the path traveled by the excitation light from the beam splitting device to the target. The beam splitting device directs expressed light to a collection subsystem for delivery to a detector.

Sandison, David R. (Moriarty, NM); Platzbecker, Mark R. (Albuquerque, NM); Descour, Michael R. (Tucson, AZ); Armour, David L. (Albuquerque, NM); Craig, Marcus J. (Albuquerque, NM); Richards-Kortum, Rebecca (Austin, TX)

1999-01-01

476

Multispectral imaging probe  

DOEpatents

A multispectral imaging probe delivers a range of wavelengths of excitation light to a target and collects a range of expressed light wavelengths. The multispectral imaging probe is adapted for mobile use and use in confined spaces, and is sealed against the effects of hostile environments. The multispectral imaging probe comprises a housing that defines a sealed volume that is substantially sealed from the surrounding environment. A beam splitting device mounts within the sealed volume. Excitation light is directed to the beam splitting device, which directs the excitation light to a target. Expressed light from the target reaches the beam splitting device along a path coaxial with the path traveled by the excitation light from the beam splitting device to the target. The beam splitting device directs expressed light to a collection subsystem for delivery to a detector. 8 figs.

Sandison, D.R.; Platzbecker, M.R.; Descour, M.R.; Armour, D.L.; Craig, M.J.; Richards-Kortum, R.

1999-07-27

477

Burstman: A portable GRB detector for really long voyages  

SciTech Connect

The renewal of the Ulysses mission to the year 2001, and the failure of Mars Observer, once more leave the Interplanetary Network with only two widely spaced components. We have therefore developed and begun to build a small GRB detector for the Russian Mars '96 mission. The first flight unit has now been delivered to Russia for spacecraft tests. Three interesting features of this experiment are first, that it measures both particles and gamma rays, second, that it is not much larger than a Walkman (hence the name), and third, that it is being constructed with support only from discretionary funds at a number of institutes. We discuss the types of measurements that Burstman will make, as well as the quantity and quality of the small error boxes that will be obtained during the two year (nominal) Mars '96 mission.

Hurley, K.; Primbsch, J. H.; Berg, P.; Ziock, K.; Mitrofanov, I.; Anfimov, D.; Chernenko, A.; Dolidze, V.; Loznikov, V.; Pozanenko, A.; Tonshev, A.; Ushakov, D.; Cline, T.; Baker, R.; Stilwell, D.; Sheppard, D.; Madden, N. [UC Berkeley Space Sciences Laboratory, Berkeley, California 94720-7450 (United States); Lawrence Livermore National Laboratory, L-296, Livermore, California 94550 (United States); Institute for Space Research Profsoyouznaya 34/32, 117810 Moscow (Russian Federation); NASA/Goddard Space Flight Center, Greenbelt, Maryland 20771 (United States); Lawrence Berkeley Laboratory, 29-204, Berkeley, California 94720 (United States)

1996-08-01

478

Space engineering  

NASA Technical Reports Server (NTRS)

Human productivity was studied for extravehicular tasks performed in microgravity, particularly including in-space assembly of truss structures and other large objects. Human factors research probed the anthropometric constraints imposed on microgravity task performance and the associated workstation design requirements. Anthropometric experiments included reach envelope tests conducted using the 3-D Acoustic Positioning System (3DAPS), which permitted measuring the range of reach possible for persons using foot restraints in neutral buoyancy, both with and without space suits. Much neutral buoyancy research was conducted using the support of water to simulate the weightlessness environment of space. It became clear over time that the anticipated EVA requirement associated with the Space Station and with in-space construction of interplanetary probes would heavily burden astronauts, and remotely operated robots (teleoperators) were increasingly considered to absorb the workload. Experience in human EVA productivity led naturally to teleoperation research into the remote performance of tasks through human controlled robots.

Alexander, Harold L.

1991-01-01

479

Optical probe  

DOEpatents

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.

Hencken, Kenneth (Pleasanton, CA); Flower, William L. (Livermore, CA)

1999-01-01

480

An unmanned probe to Pluto  

NASA Technical Reports Server (NTRS)

Now that Voyager II has completed its grand tour of the solar system, all the planets in the solar system, with the exception of Pluto, have been studied. Even now, missions to return to Mercury, Venus, Mars Jupiter, and Saturn are currently flying or are planned. However, a mission to explore Pluto is not, at the present time, being considered seriously. The design problem presented to the students was very general, i.e., design an unmanned mission to Pluto with a launch window constraint of the years 2000 to 2010. All other characteristics of the mission, such as mission type (flyby, orbiter, lander, penetrator), scientific objectives and payload, and the propulsion system were to be determined by the design teams. The design studies exposed several general problems to be solved. Due to the extreme distance to Pluto (and a corresponding travel time in the range of 10 to 25 years), the spacecraft had to be lighter and more robust than current spacecraft designs. In addition, advanced propulsion concepts had to be considered. These included the new generation of launch vehicles and upper stages and nuclear electric propulsion. The probe design offered an abundance of synthesis and analysis problems. These included sizing trade studies, selection of subsystem components, analysis of spacecraft dynamics, stability and control, structural design and material selection, trajectory design, and selection of scientific equipment. Since the characteristics of the mission, excluding the launch window, were to be determined by the design teams, the solutions varied widely.

1990-01-01

481

Effect of mid-oceanic ballast water exchange on virus-like particle abundance during two trans-Pacific voyages.  

PubMed

Ballast water is a potential source of invasive species, including viruses that target a variety of hosts. We sampled ballast during two trans-Pacific voyages and analyzed the efficacy of mid-oceanic exchange in reducing virus-like particle (VLP) abundance. Exchange did not significantly reduce virus abundance during the first voyage (P=0.874), whereas it reduced viral abundance 3.9-fold from 1.8 × 10(7) to 0.47 × 10(7) VLP mL(-1) during the second voyage (P<0.0001). Despite the impact of exchange during the second voyage, virus abundances were not significantly different between exchanged and unexchanged tanks upon arrival in Canada (P=0.363) and Canadian port water samples (P=0.502). Regressions between environmental parameters and VLP abundance uncovered negative correlations between salinity and viral abundance during one, and dissolved oxygen and viral abundance during the second voyage. In summary, ballast tanks are highly variable with respect to total virus abundance, and the efficacy of exchange requires investigation into the dynamics of specific viruses. PMID:21345458

Leichsenring, Jonas; Lawrence, Janice

2011-05-01

482

Preliminary estimation of color inhomogeneities on the surface of Venus according to the television images obtained by the VENERA-13 and VENERA-14 automated space probes  

NASA Technical Reports Server (NTRS)

Digital processing of images obtained by the Venera 13 and Venera 14 probes led to the discovery of faint color differences of some areas of the observed surface. Maximum color differences were observed in the right part of 14-1 panorama. Color anomaly is associated with the bedrock outcrop having slightly higher albedo than the surrounding. Possible causes of the discovered color differences are discussed.

Shkuratov, Yu. G.; Kreslavskiy, M. A.; Bazilevskiy, A. T.

1987-01-01

483

Construction of the Hunveyor-Husar space probe model system for planetary science education and analog studies and simulations in universities and colleges of Hungary  

Microsoft Academic Search

Several teachers and students had the possibility to visit International Space Camp in the vicinity of the MSFC NASA in Huntsville Alabama USA where they learned the success of simulators in space science education To apply these results in universities and colleges in Hungary we began a unified complex modelling in planetary geology robotics electronics and complex environmental analysis by

Sz. Bérczi; S. Hegyi; Gy. Hudoba; H. Hargitai; A. Kokiny; B. Drommer; A. Gucsik; A. Pintér; Zs. Kovács

2006-01-01

484

A three dimensional probe positioner  

SciTech Connect

In order to sort out the physics that is important in many plasma experiments, data in three dimensions (3D) are becoming necessary. Access to the usual cylindrical vacuum vessel is typically restricted to radially or axially insertable probes that can pivot. The space that can be explored usually has significant restrictions either because probe travel must be along a travel path, or a 'wobbly' probe positioner requires one to map between a moveable coordinate system and a preferred laboratory coordinate system. This could for example introduce errors in measurements of vector quantities such as magnetic field or flow. We describe the design and implementation of a 3D probe positioner that slides in two dimensions on a double O-ring seal and radially inserts along the third dimension. The net result is that a 3D space can be explored in a laboratory Cartesian reference frame.

Intrator, T.; Sun, X.; Furno, I. [Los Alamos National Laboratory, Los Alamos, New Mexico, 87545 (United States); Dorf, L. [Applied Materials, 3050 Bowers Avenue, Santa Clara, California 95054-3299 (United States); Lapenta, G. [Centrum voor Plasma-Astrofysica, Katholieke Universiteit Leuven, 3001 Belgium (Belgium)

2008-10-15

485

Exploring steric constraints on protein mutations using MAGE0PROBE  

E-print Network

. The interactive MAGE0PROBE system lets the biologist explore conformational space for the mutant side chain function in PROBE systematically explores that same conformational space, outputting contact scores at eachExploring steric constraints on protein mutations using MAGE0PROBE J. MICHAEL WORD,1,3 ROBERT C

Richardson, David

486

Study of dust in the vicinity of Dione using the Voyager 1 plasma wave instrument  

NASA Technical Reports Server (NTRS)

The flyby of Voyager 1 at Saturn yielded the detection of a large variety of plasma waves, for example, chorus, hiss, and electron cyclotron harmonics. Just before the outbound equator crossing, the Voyager 1 plasma wave instrument detected a strong, well-defined low-frequency enhancement in signal levels. Initially, it was thought that this enhancement was due to plasma waves, but more recently it was suggested that dust impacts might be at least partial contributors. In this report we present evidence that dust impacts are partly responsible for the low-frequency enhancement. A new method of analysis which relies mainly on the 16-channel spectrum analyzer has been used to derive the dust impact rate. The available wideband waveform observations (which have been used previously to study dust impacts) were useful for calibrating the impact rate from the spectrum analyzer data. The mass and hence size of the dust particles were also obtained by analyzing the response of the plasma wave spectrum and analyzer. The results show that the region sampled by Voyager 1 is populated by dust particles that have rms masses of up to a few times 10(exp -11) g and sizes of up to a few microns. The dust particle number density is of the order of 10(exp -3)/cu m. The optical depth of the region sampled by the spacecraft is approximately 10(exp -6). The particle population is centered at 2470 (+/- 150) km south of the equatorial plane and has a north-south FWHM (full-width, half-maximum) thickness of 4130 (+/- 450) km. The dust may be part of the E ring or a localized ringlet assoicated with Dione.

Tsintikidis, D.; Kurth, W. S.; Gurnett, D. A.; Barbosa, D. D.

1995-01-01

487

Estimation of a genetically viable population for multigenerational interstellar voyaging: Review and data for project Hyperion  

NASA Astrophysics Data System (ADS)

Designing interstellar starships for human migration to exoplanets requires establishing the starship population, which factors into many variables including closed-ecosystem design, architecture, mass and propulsion. I review the central issues of population genetics (effects of mutation, migration, selection and drift) for human populations on such voyages, specifically referencing a roughly 5-generation (c. 150-year) voyage currently in the realm of thought among Icarus Interstellar's Project Hyperion research group. I present several formulae as well as concrete numbers that can be used to help determine populations that could survive such journeys in good health. I find that previously proposed such populations, on the order of a few hundred individuals, are significantly too low to consider based on current understanding of vertebrate (including human) genetics and population dynamics. Population genetics theory, calculations and computer modeling determine that a properly screened and age- and sex-structured total founding population (Nc) of anywhere from roughly 14,000 to 44,000 people would be sufficient to survive such journeys in good health. A safe and well-considered Nc figure is 40,000, an Interstellar Migrant Population (IMP) composed of an Effective Population [Ne] of 23,400 reproductive males and females, the rest being pre- or post-reproductive individuals. This number would maintain good health over five generations despite (a) increased inbreeding resulting from a relatively small human population, (b) depressed genetic diversity due to the founder effect, (c) demographic change through time and (d) expectation of at least one severe population catastrophe over the 5-generation voyage.

Smith, Cameron M.

2014-04-01

488

Energetic Particles in the Heliosheath: A Report from Voyagers 1 and 2 (Invited)  

NASA Astrophysics Data System (ADS)

Both Voyager spacecraft are now in the heliosheath and observing several populations of energetic particles. At the lowest energies, there is a population, which we refer to as Termination Shock Particles (TSPs), which we attribute to local acceleration at the termination shock in the vicinity of where the spacecraft crossed it. At Voyager 1 (V1), this population has been very steady for the last four years, since about a year after shock crossing. At Voyager 2 (V2), the TSP spectrum has been variable, particularly at energies of a few MeV, for about 1.5 years since the shock crossing in August-September 2007. Recently, the variations have become smaller and the intensity vs. time profiles resemble those at V1. At mid-energies, the anomalous cosmic ray (ACR) energy spectra continue to evolve, responding to decreasing solar modulation and to motion through a spatial gradient. The ACR source must be beyond the position of V1 and could be near the heliopause or on the termination shock somewhere other than where V1 and V2 crossed it. At the highest energies, galactic cosmic ray (GCR) ions appear to have a very small spatial gradient. Since the measured GCR ion intensities are well below the intensities thought to be present just outside the heliosphere, there may be a region of enhanced modulation beyond V1. We will report the latest observations of these particle populations in order to better understand their source and propagation characteristics. This work was supported by NASA under contract NAS7-0301.

Cummings, A. C.; Stone, E. C.; McDonald, F. B.; Heikkila, B. C.; Lal, N.; Webber, W. R.

2009-12-01

489

Radiation Transport of Heliospheric Lyman-alpha from Combined Cassini and Voyager Data Sets  

NASA Technical Reports Server (NTRS)

Heliospheric neutral hydrogen scatters solar Lyman-alpha radiation from the Sun with '27-day' intensity modulations observed near Earth due to the Sun's rotation combined with Earth's orbital motion. These modulations are increasingly damped in amplitude at larger distances from the Sun due to multiple scattering in the heliosphere, providing a diagnostic of the interplanetary neutral hydrogen density independent of instrument calibration. This paper presents Cassini data from 2003-2004 obtained downwind near Saturn at approximately 10 AU that at times show undamped '27-day' waves in good agreement with the single-scattering models of Pryor et al., 1992. Simultaneous Voyager 1 data from 2003- 2004 obtained upwind at a distance of 88.8-92.6 AU from the Sun show waves damped by a factor of -0.21. The observed degree of damping is interpreted in terms of Monte Carlo multiple-scattering calculations (e.g., Keller et al., 1981) applied to two heliospheric hydrogen two-shock density distributions (discussed in Gangopadhyay et al., 2006) calculated in the frame of the Baranov-Malama model of the solar wind interaction with the two-component (neutral hydrogen and plasma) interstellar wind (Baranov and Malama 1993, Izmodenov et al., 2001, Baranov and Izmodenov, 2006). We conclude that multiple scattering is definitely occurring in the outer heliosphere. Both models compare favorably to the data, using heliospheric neutral H densities at the termination shock of 0.085 cm(exp -3) and 0.095 cm(exp -3). This work generally agrees with earlier discussions of Voyager data in Quemerais et al., 1996 showing the importance of multiple scattering but is based on Voyager data obtained at larger distances from the Sun (with larger damping) simultaneously with Cassini data obtained closer to the Sun.

Pryor, W.; Gangopadhyay, P.; Sandel, B.; Forrester, T.; Quemerais, E.; Moebius, E.; Esposito, L.; Stewart, I.; McClintock, W.; Jouchoux, A.; Colwell, J.; Izmodenov, V.; Malama, Y.; Shemansky, D.; Ajello, J.; Hansen, C.; Bzowski, M.

2008-01-01

490