Note: This page contains sample records for the topic voyager space probes from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

Voyager at the Edge of Interstellar Space  

NASA Astrophysics Data System (ADS)

Following encounters with Jupiter, Saturn, Uranus, and Neptune, the two Voyager spacecraft continued exploring the outer heliosphere as they searched for the heliopause, the boundary between the solar wind and the local interstellar medium. On August 25, 2012, Voyager 1 entered an unexpected region near the boundary in which the spiral solar magnetic field lines appear to be well connected to interstellar space, allowing the escape of energetic ions from inside the heliosphere and the entry of low energy galactic cosmic rays from outside. These observations have revealed new aspects of the boundary region of the heliosphere and provide a first view of what is outside.

Stone, Edward C.

2013-10-01

2

Voyager 1 encounters new region of space  

NASA Astrophysics Data System (ADS)

Voyager 1, which left Earth in 1977 and is now about 10 billion miles away, has entered a region of space with strange anomalies, according to project scientist Ed Stone, former director of the Jet Propulsion Laboratory. The spacecraft has encountered magnetic potholes and bumps-areas where the magnetic field of the heliosheath either nearly vanishes or doubles, respectively. It also has encountered `anomalous cosmic rays' that are less energetic, and thus less dangerous, than galactic cosmic rays. In addition, the solar wind in the heliosheath has been slower than scientists had expected, only about 54,700 kilometers per hour compared with the predicted 322,000-483,000 kilometers per hour. Voyager 1 is expected to reach the edge of the heliosheath in about 10 years.

Zielinski, Sarah

2006-10-01

3

Simplistic propulsion analysis of a breakthrough space drive for Voyager  

NASA Astrophysics Data System (ADS)

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 program to search for further advances in physics to circumvent these limitations. One of the goals of this program is to discover a new method of propulsion that eliminates the need for propellant. A simplistic analysis is offered in this paper to assess the trip-time benefit of this single goal, using the Voyager spacecraft as a basis. The existing propulsion performance of the Voyager spacecraft is compared to its performance assuming it was equipped with a breakthrough physics space drive that could convert energy directly into kinetic energy. Given that the physics does not yet exist for such a space drive, these comparisons are at the most rudimentary level, based on energy comparisons. Specifically, the velocity and distance covered by the Voyager spacecraft are compared to that achievable by a hypothetical space drive using the same energy available to the existing Voyager. The additional benefit of having the Voyager's Radioisotope Thermoelectric Generators (RTGs) supply propulsion power is also considered. .

Boston, Malcolm D. K.

2000-01-01

4

Deep space observations of the east-west asymmetry of solar energetic storm particle events: Voyagers 1 and 2  

Microsoft Academic Search

Measurements of energetic proton (E\\/sub p\\/ > or =520 keV) intensities by The Johns Hopkins University Applied Physics Laboratory instruments on board the Voyagers 1 and 2 deep space probes, during solar flare-induced shock waves, indicate that the formation of solar energetic storm particle (ESP) events depends critically on the heliolongitudes of different locations on the large-scale shock front with

E. T. Sarris; R. B. Decker; S. M. Krimigis

1985-01-01

5

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

6

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

7

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

8

Probing the Nature of the Heliosheath with the Neutral Atom Spectra Measured by IBEX in the Voyager 1 Direction  

NASA Astrophysics Data System (ADS)

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.; McComas, D. J.; Schwadron, N. A.; Drake, J. F.

2013-10-01

9

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

10

Anatomy of a Space Probe  

Microsoft Academic Search

\\u000a Robotic space probes usually do not look like people or animals. Rather than resembling the human-looking science fiction\\u000a movie robots C3PO and Data, they have more in common with the squat, cylindrical R2D2. Like this famous robot from Star Wars, our spacecraft normally do not sport arms, legs, eyes and ears as we do, but they nevertheless function very well

Michel Pelt

11

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

12

Confronting Observations and Modeling: The Role of the Interstellar Magnetic Field in Voyager 1 and 2 Asymmetries  

Microsoft Academic Search

Magnetic effects are ubiquitous and known to be crucial in space physics and astrophysical media. We have now the opportunity\\u000a to probe these effects in the outer heliosphere with the two spacecraft Voyager 1 and 2. Voyager 1 crossed, in December 2004,\\u000a the termination shock and is now in the heliosheath. On August 30, 2007 Voyager 2 crossed the termination shock, providing\\u000a us for the

M. Opher; J. D. Richardson; G. Toth; T. I. Gombosi

2009-01-01

13

Confronting Observations and Modeling: The Role of the Interstellar Magnetic Field in Voyager 1 and 2 Asymmetries  

Microsoft Academic Search

Magnetic effects are ubiquitous and known to be crucial in space physics and astrophysical media. We have now the opportunity\\u000a to probe these effects in the outer heliosphere with the two spacecraft Voyager 1 and 2. Voyager 1 crossed, in December 2004,\\u000a the termination shock and is now in the heliosheath. On August 30, 2007 Voyager 2 crossed the termination shock, providing\\u000a us for the

M. Opher; J. D. Richardson; G. Toth; T. I. Gombosi

14

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. Bjřrk

15

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. Bjřrk

2007-01-01

16

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

17

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

18

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.

19

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.

20

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

21

Risk of nuclear powered space probes  

Microsoft Academic Search

In recent years, three probes have been sent into outer space: Galileo, Ulysses and Cassini. Each has used for its electricity power source, a radioactive thermoelectric generator (RTG), heated by a source of plutonium 238. Cassini, launched in October 1997, will reach its scientific objective in late June or early July 2004, concurrent with PSAM7. The authors of this paper

W. E Kastenberg; Richard Wilson

2004-01-01

22

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

23

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

24

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

25

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

26

Maiden voyage.  

PubMed

The scientific debate which developed during the eighteenth century, proposed and diffused new theories on the generation not only within the scientific community. Microscopic investigation and various experimental campaigns fostered daring models attempting to unveil the natural phenomena from which life originates. Besides the famous scientific and philosophical works that marked the age, in the second part of the century two pamphlets appeared that well represent the importance of the querelle about embryological systems defining the concept of generation as a voyage within the human body. Lucina sine concubitu and Juno abortans, respectively published in England and in Germany between 1750 and 1760, narrate the odd and imaginary adventures of two doctors who are trying to interrupt and modify the embryos' journey towards the body of the mother. PMID:21936203

De Santis, Dario

2011-01-01

27

Voyager cartography  

NASA Astrophysics Data System (ADS)

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.

1987-05-01

28

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

29

Huygens space probe ready to leave Europe  

NASA Astrophysics Data System (ADS)

Over the past year, the Huygens probe has been integrated and extensively tested at the facilities of Daimler Benz Aerospace Dornier Satellitensysteme in Ottobrunn near Munich. It was designed and developed for ESA by a European industrial consortium led by Aerospatiale (F) as prime contractor. The European activities have been successfully completed and this is to be formalised by the Flight Acceptance Review which will release the probe for shipment to the USA. To mark this important milestone a press briefing is scheduled for Wednesday, 26 March at 10.00 hours at Daimler-Benz Aerospace Dornier Satellitensysteme in Ottobrunn. The detailed programme of the press briefing is attached. If you wish to attend the press briefing, please complete the attached accreditation form and return it, preferably by fax, to : Daimler Benz Aerospace Dornier Satellitensysteme Mr. Mathias Pikelj, Fax. + 49 7545 8 5589, Tel. + 49 7545 8 9123 NOTE FOR THE EDITORS: Background facts about the Cassini Huygens mission Huygens is a medium-sized mission of ESA's Horizons 2000 programme for space science, and a contribution to the joint NASA ESA Cassini mission. Christiaan Huygens discovered Saturn s moon Titan in 1655, and the mission named after him aims to land a 343 kilogram probe on Titan carrying a package of scientific instruments through the atmosphere. Six sets of instruments will analyse the chemical composition of the atmosphere, observe the weather and topography of Titan, and examine the nature of its surface. Titan is larger than the planet Mercury, and its unique atmosphere, rich in nitrogen and hydrocarbons, may resemble the atmosphere of the primitive Earth, before life began. Nominal dates for the Huygens mission are as follows: * launch, 6 October 1997 * arrival at Saturn, 1 July 2004 * release of Huygens, 6 November 2004 * entry into Titan's atmosphere, 27 November 2004. The Saturn Orbiter, the other element in the Cassini mission, will relay the signals from Huygens to the Earth, before settling down to prolonged observations of Saturn and its rings and moons. European and American scientists are partners in all the experiments, both in the Orbiter and in the Huygens Probe. Farthest out for Europe Huygens will travel to a greater distance from the Sun than any previous ESA mission, out to the orbit of Saturn at 1400 million kilometres, or nearly ten times the Sun Earth distance. For comparison, the farthest ranging mission at present is Ulysses, orbiting over the poles of the Sun and out to the orbit of Jupiter, 800 million kilometres from the Sun. As no other mission planned or contemplated by ESA at present will go as far as Saturn, Huygens is likely to hold the European record for many years. HUYGENS READY TO LEAVE EUROPE PRESS BRIEFING Wednesday 26 March, 10:00 hrs. Location : Daimler-Benz Aerospace/ Dornier Satellitensysteme Gate 2, Building 5.1 Ludwig-B>lkow-Allee Ottobrunn (Munich) Programme: 10h00 Registration of press 10h15 Huygens video introduction 10h20 Welcoming addresses: Klaus Ensslin, President, Dornier Satellitensysteme Roger Bonnet, Director of Science, ESA Michel Delaye, President, Aerospatiale Espace & Defense 10h30 NASA News and Cassini status Wesly T. Huntress, Associate Administrator of Space Science, NASA Richard Spehalski, Head of Cassini Project, NASA/JPL 10h40 The Huygens Project: Hamid Hassan, Head of the Huygens Project, ESA/ESTEC Hans-Joachim Hoffman, Head of the Huygens Project, Dornier Satellitensysteme Gerard Huttin, Head of the Huygens Project, Aerospatiale 11h00 The Huygens Scientific Programme: Jean-Pierre Lebreton, Huygens Project Scientist, ESA supported by European and American scientists. 11h15 The ESA Science programme, current and future missions Roger Bonnet, Director of Science, ESA 11h25 Question and Answer session 11h55 Visit to the Huygens spacecraft (access inside the clean room limited to photographers and TV teams only). 12h45 Buffet lunch 14h00 End of activties HUYGENS READY TO LEAVE EUROPE PRESS BRIEFING Wednesday 26 March, 10:00 hrs. Location : Daimler-Benz Aerospace

1997-03-01

30

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.

31

Voyager-1 Observations of MeV Ions and Electrons in the Vicinity of the Heliospheric Termination Shock  

NASA Astrophysics Data System (ADS)

Beginning in 2002.5 at a heliospheric distance of some 85AU, the CRS (Cosmic Ray Subsystem) experiment on Voyager-1 observed two large increases in MeV ions and electrons accompanied by more modest increases in Galactic and Anomaloous cosmic rays (GCR and ACRs). The first event persisted for some 6.5 months and was terminated by the passage of a large outward moving interplanetary disturbance. The second event, which began in 2003.62, is still in progress more than a year later. We have interpreted these events as the expected energetic particle precursors as Voyager-1 approaches the heliospheric termination shock and we have termed them TSP (Termination Shock Particle) increases. There are small, but significant, differences between TSP 1 and 2 both in the time history of the ions and electrons and in the short term (13 - 52 day) variations. In addition the GCR and ACR flux levels are somewhat smaller for the 2nd event. These TSP events have not yet been observed at Voyager-2, which is at a heliocentric distance some 18AU less than Voyager-1. However, at Voyager-2 there is a remarkable series of solar/interplanetary energetic particle events associated with specific episodes of solar activity. The effects of these interplanetary transients is clearly evident in the time history of the Voyager-1 TSPs, thus providing another means of probing this new region of space.

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

2004-12-01

32

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

33

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

34

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

35

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

36

Probing Protein Fold Space with a Simplified Model  

Microsoft Academic Search

We probe the stability and near-native energy landscape of protein fold space using powerful conformational sampling methods together with simple reduced models and statistical potentials. Fold space is represented by a set of 280 protein domains spanning all topological classes and having a wide range of lengths (33–300 residues) amino acid composition and number of secondary structural elements. The degrees

Peter Minary; Michael Levitt

2008-01-01

37

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

38

The Huygens probe—space history in many ways  

Microsoft Academic Search

The European Space Agency's Huygens probe, developed under the prime contractorship of Alcatel Alenia Space, has on the 14th January 2005 arrived at its final destination, Saturn's largest Moon Titan. This event provides a major step in our solar system exploration activities and represents a significant contribution to the exploration of Titan, an Earth-like body in many respects. The road

Anne Marie Schipper; Jean-Pierre Lebreton

2006-01-01

39

Space Exploration; Power Sources for Deep Space Probes.  

National Technical Information Service (NTIS)

The National Aeronautics and Space Administration (NASA) launched its nuclear powered Cassini spacecraft on October 15, 1997, on a 12 year mission to Saturn. You asked that we review the use of nuclear power systems for Cassini and other space missions. A...

1998-01-01

40

Space telescopes, interstellar probes and directed panspermia  

NASA Astrophysics Data System (ADS)

Giant telescopes in interplanetary space can measure the distances, velocities, and atmospheric composition of extrasolar planets. Such telescopes can very dramatically reduce the cost of unpeopled interstellar missions much as ground based astronomy has reduced the cost of interplanetary exploration. A long (not less than 100,000 km) linear accelerator located in interplanetary space can accurately propel pods containing trillions of living spores into interstellar space. Together the telescopes and the accelerator should make it possible to hit all interesting planets within a 100 light year radius of the sun. If, as is often argued, there are numerous long-lived technical civilizations in the Milky Way galaxy, then life on earth may well have originated elsewhere.

Zuckerman, B.

1981-09-01

41

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

42

Voyager at Uranus: 1986.  

National Technical Information Service (NTIS)

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 ultraviol...

1986-01-01

43

Infrared spectrometer for Voyager  

Microsoft Academic Search

The Voyager IR investigation is described, which uses a Michelson interferometer in the 180-2500\\/cm range, and a single-channel radiometer for the visible and near-IR, sharing a 50-cm diameter telescope. Emphasis is placed on the differences between the Voyager and the previous designs, including reductions in the field of view and in the noise equivalent spectral radiance of the instrument. Attention

R. Hanel; D. Crosby; L. Herath; D. Vanous; D. Collins; H. Creswick; C. Harris; M. Rhodes

1980-01-01

44

Stochastic voyages into uncharted chemical space produce a representative library of all possible drug-like compounds.  

PubMed

The "small molecule universe" (SMU), the set of all synthetically feasible organic molecules of 500 Da molecular weight or less, is estimated to contain over 10(60) structures, making exhaustive searches for structures of interest impractical. Here, we describe the construction of a "representative universal library" spanning the SMU that samples the full extent of feasible small molecule chemistries. This library was generated using the newly developed Algorithm for Chemical Space Exploration with Stochastic Search (ACSESS). ACSESS makes two important contributions to chemical space exploration: it allows the systematic search of the unexplored regions of the small molecule universe, and it facilitates the mining of chemical libraries that do not yet exist, providing a near-infinite source of diverse novel compounds. PMID:23548177

Virshup, Aaron M; Contreras-García, Julia; Wipf, Peter; Yang, Weitao; Beratan, David N

2013-05-02

45

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

46

Jovian magnetosphere: a post-Voyager view  

SciTech Connect

Results of observational and theoretical work presented at the Rice University Conference on the Physics of the Jovian Magnetosphere (February 27-29, 1980) are summarized and used to elucidate the post-Voyager status of the understanding of Jovian magnetosphere dynamics. Works considered treat earth-based and Voyager observations of the Io torus, decametric and kilometric radio emissions, corotation of magnetospheric plasma with the magnetic field, and theoretical studies of mechanisms of particle acceleration, diffusion and loss in the magnetosphere and interplanetary space. Issues remaining to be resolved by future research are also indicated, particularly questions of the discrepancy between plasma flow measurements obtained on the two plasma experiments on each Voyager spacecraft, and the localization of the source of torus plasma.

Hill, T.W.

1981-01-20

47

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

48

Two Voyagers to Saturn  

NASA Astrophysics Data System (ADS)

The pages which follow may be taken as a celebration of the impending encounter of Voyager 2 with Saturn and are a pointer to the richness of data likely to be gathered in the next few days and weeks. Although there may be some to whom the work of these two remarkable spacecraft will be proof of how even more remarkable would have been the Grand Tour of the Solar System planned in the 1960s but executed only in the form of the two Voyagers, to most people the encounters with Jupiter and Saturn will seem exciting enough for the time being. Yet there are Uranus and Neptune to come. This group of scientific articles includes some of the first detailed attempts to make sense of last year's Voyager 1 observations of Saturn-and Nature acknowledges its debt to Dr G. E. Hunt of University College, London for having helped to recruit these articles and to give shape to the ground they cover. The scope is necessarily restricted, for there is hardly a branch of planetary astronomy which has not been changed in some way by the data from Voyager 1-and which is not about to be changed again.

1981-08-01

49

Pu-powered space probes face uncertain future  

SciTech Connect

When fragments of comet Shoemaker-Levy 9 crashed into the gas clouds of Jupiter in July, the only representatives of humankind with a good view were a trio of spacecraft, Voyager 2, Galileo, and Ulysses. Radioisotope thermoelectric generators (RTGs) supplied by the Department of Energy provided the power to run the observing instruments on these spacecraft, but now that source of power-and all deep-space missions-may be in jeopardy. Despite the fact that the recently passed congressional appropriations bill increased funding for the RTG program by nearly 20 percent, from $51 million in 1994 to $61 million in 1995, rumors persist that the program is in danger of being discontinued. Peter Ulrich, chief of the Flight Programs Branch of the Solar System Exploration Division of the Office of Space Science at NASA, was confident that the program would stay alive through NASA`s next mission. RTGs will be on board the Cassini spacecraft scheduled to blast off in 1997 for an exploration of Saturn and its rings and moons. RTG`s use the heat produced by the alpha decay of plutonium-238 to heat a thermocouple, which generates electricity. Cassini is designed to carry three RTGs, producing a total of 750 W of electricity initially, decreasing to about 600 W by the time it reaches Saturn seven years after launch. The RTGs on Cassini will carry a total of about 70 lb of plutonium oxide. RTGs have no moving parts. They are simple, rugged, and reliable. According to Ulrich, {open_quotes}It`s really a very well-matched power source for something like a remote mission.{close_quotes} The political situation is less clear, though. {open_quotes}What I hear unofficially is funding looks dime,{close_quotes} said the DOE spokesperson, {open_quotes}and the lights are being turned off for these missions.{close_quotes} If that happens, the lights will go out on NASA`s deep-space missions to other parts of our solar system.

NONE

1994-10-01

50

The Radiation Belt Storm Probes (RBSP) and Space Weather  

NASA Astrophysics Data System (ADS)

Following the launch and commissioning of NASA's Radiation Belt Storm Probes (RBSP) in 2012, space weather data will be generated and broadcast from the spacecraft in near real-time. The RBSP mission targets one part of the space weather chain: the very high energy electrons and ions magnetically trapped within Earth's radiation belts. The understanding gained by RBSP will enable us to better predict the response of the radiation belts to solar storms in the future, and thereby protect space assets in the near-Earth environment. This chapter details the presently planned RBSP capabilities for generating and broadcasting near real-time space weather data, discusses the data products, the ground stations collecting the data, and the users/models that will incorporate the data into test-beds for radiation belt nowcasting and forecasting.

Kessel, R. L.; Fox, N. J.; Weiss, M.

2012-12-01

51

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

52

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.

53

Voyager mission telecommunication firsts  

NASA Astrophysics Data System (ADS)

The communications breakthroughs achieved during the NASA Voyager mission are discussed. The dual-spacecraft mission to Jupiter, Saturn, Uranus, Neptune, and their moons and rings was launched in 1977 and completed interplanetary phase some 12 years later with the Voyager 2 Neptune encounter in August 1989. The radio telemetry, coding, and navigation equipment of the spacecraft are examined in detail. Firsts achieved in the radio science area are also discussed. These include the fact that it was the first mission specifically designed to obtain radio-science data. It had very exacting requirements for radio system stability, both at S- and X-bands, and for frequency and timing system stability, both flight and ground.

Posner, Edward C.; Madsen, Boyd D.; Rauch, Lawrence L.

1990-09-01

54

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

55

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

56

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

57

IEC Thrusters for Space Probe Applications and Propulsion  

NASA Astrophysics Data System (ADS)

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.; Teofilo, Vince L.; Burton, Rodney; Dell, Richard; Dell, Dick; Hargus, William A.

2009-03-01

58

An Interesting Voyage  

NASA Astrophysics Data System (ADS)

My life has been an interesting voyage. I became an astronomer because I could not imagine living on Earth and not trying to understand how the Universe works. My scientific career has revolved around observing the motions of stars within galaxies and the motions of galaxies within the Universe. In 1965, if you were very lucky and interested in using telescopes, you could walk into a research laboratory that was building instruments that reduced exposure times by a factor of 10 and end up making remarkable discoveries. Women generally required more luck and perseverance than men did. It helped to have supportive parents and a supportive husband.

Rubin, Vera C.

2011-09-01

59

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.

Meertens, Chuck

60

Engineering the Voyager Uranus mission  

Microsoft Academic Search

Several factors that affected the continuing expedition of Voyager 2 to Uranus are discussed. The hydrazine propellant and electrical power supplies on the spacecraft, and the radio signal strength and sun sensor and star tracker sensitivities are examined. The use of the on-board computer to steady the spacecraft and reduce image smear is described. The Voyager employs radiometric and optical

R. P. Laeser

1986-01-01

61

Voyager photometry of Io  

SciTech Connect

Detailed disk-integrated and disk-resolved photometric studies of the Jovian moon Io were carried out using Voyager images. Disk-integrated properties derived from the Voyager data, such as phase curves, rotation curves, geometric albedos, phase integrals, and the Bond albedo, are generally consistent with earth-based estimates. Near-opposition limb-darkening behavior, as parameterized by the Minnaert photometric function, has been accurately measured for regions on the surface of Io in three distinct color classes: Bright (white), Average (orange), and Polar (brown). The limb-darkening results allow derivation of accurate near-opposition disk-resolved phase curves, revealing substantial differences in opposition surge among the color classes. Modeling of the phase curves using the Hapke photometric function supports the contention that the uppermost layer of the Ionian surface is on average extremely porous, and suggests that this layer is substantially more porous in Average and Polar areas than in the Bright regions, a difference consistent with models of Io's surface layer. Combination of limb-darkening and phase information leads to determination of accurate normal reflectance spectra for the color classes; careful comparison with laboratory data supports earlier claims that the spectra of Ionian materials can be explained by mixtures of sulfur and SO/sub 2/ frost, although this is not a unique diagnostic identification.

Simonelli, D.P.

1987-01-01

62

Amalthea - Voyager imaging results  

NASA Astrophysics Data System (ADS)

Voyager images of Amalthea are presented, which reveal an irregular satellite in synchronous rotation relative to Jupiter with dimensions of 270 x 165 x 150 km. The surface appears scarred by large craters and sharp ridges to indicate a history of cosmic battering. Amalthea'a normal surface reflectance is 5-6% with a very red color and a mean opposition angle magnitude of +14. The phase coefficient between phase angles of 0.8 and 42 deg of 0.042 + or - 0.004 mag/deg indicates that the phase integral does not exceed 0.3 and the Bond Albedo is less than 0.02. Several prominent bright spots of 10-50 km across occur on local slopes and ridges, have albedos several times higher than the background, and have a greenish color where the spectrum bends down beyond 0.56 microns.

Ververka, J.; Thomas, P.; Davies, M. E.; Morrison, D.

1981-09-01

63

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

64

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

65

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

66

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

67

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.

Grove, Karen

1998-12-10

68

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

69

Engineering the Voyager Uranus mission  

NASA Astrophysics Data System (ADS)

Several factors that affected the continuing expedition of Voyager 2 to Uranus are discussed. The hydrazine propellant and electrical power supplies on the spacecraft, and the radio signal strength and sun sensor and star tracker sensitivities are examined. The use of the on-board computer to steady the spacecraft and reduce image smear is described. The Voyager employs radiometric and optical data to navigate. The changes required to improve the transmission capabilities of the spacecraft and to eliminate the on-board hardware failures are analyzed.

Laeser, R. P.

1986-10-01

70

Aeronautics and Space Report - 1979.  

National Technical Information Service (NTIS)

This report includes the following titles from the year 1979: Aircraft Spin Tests; The Voyagers; Electric Car Tests; Astronaut Ana L. Fisher; Space Shuttle Columbia; Voyager One, Early Results; Apollo 11, The First Step; Advances in Avionics; Wind Power; ...

1994-01-01

71

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

72

Voyager 1 Explores the Heliosheath  

NASA Astrophysics Data System (ADS)

Since crossing the inward moving termination shock at 94 AU on December 16, 2004, Voyager 1 has revealed both expected and unexpected aspects of the heliosheath. The magnetic field was compressed by a factor of 3 across the shock, indicating a weak shock. However, for >5 solar rotations the magnetic polarity at Voyager 1 was unexpectedly positive, corresponding to the south polar magnetic field even though Voyager 1 is at 34 degrees north. This suggests that the radial speed of the heliosheath plasma convecting the magnetic filed must be comparable to that of Voyager 1 (17 km/s). A low speed is also evident in the small radial anisotropy of low energy ions and could result from a high inward shock speed or from a significant meridional deflection of the plasma flow. The shock is a steady source low energy (<3.5 MeV/nuc) termination shock particles (TSPs) with a spectrum consistent with diffusive acceleration at a weak shock. The TSP spectrum is also consistent with shock heating of interstellar pickup ions. In contradiction to expectations, the intensity of anomalous cosmic rays (ACRs) with >10 MeV/nuc did not peak at the shock, but continued to increase in the heliosheath, indicating that the ACR source is yet to be found. The intensities of galactic cosmic ray nuclei and electrons have also increased since crossing the shock as the effects of solar modulation continue to decrease. These and other recent results will be summarized.

Stone, E. C.

2005-12-01

73

The Voyage of the MIMI.  

ERIC Educational Resources Information Center

The Voyage of MIMI is a major educational project housed at Bank Street College (New York) which is directed toward the development of extensive television, computer software, videodisc, and print materials for use in science and mathematics education in grades 5-7. The first series has been completed, and includes a 13-part dramatic television…

Gibbon, Sam; Hooper, Kristina

1986-01-01

74

European Space Agency studies of the solar probe  

Microsoft Academic Search

The feasibility and scientific objectives of a solar probe were studied by a Mission Definition Group in 1975 and 1976. The orbit analysis program was developed and an extended study of the orbit analysis was done in 1977. The results of these studies are in the Report of the Mission Definition Study (1976) and an E.S.O.C. report (1978), and the

I. W. Roxburgh

1978-01-01

75

Probing Galactic Dynamics with the Space Interferometry Mission  

Microsoft Academic Search

The Space Interferometry Mission will be the first spatial long-baseline optical interferometer in space. SIM, scheduled to launch in 2005, is designed to perform wide-angle astrometry with 4 mu arcsec precision on objects as faint as V = 20, using a 10-meter baseline. This level of precision will allow SIM to measure stellar parallax distances to 10% and transverse velocities

Stephen C. Unwin

1998-01-01

76

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

77

Endeavour's Final Voyage  

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 storied flying career for the youngest of NASA's shuttle orbiters.

KSC Web Team

2011-04-28

78

Reagent based DOS: A "Click, Click, Cyclize" strategy to probe chemical space†  

PubMed Central

The synthesis of small organic molecules as probes for discovering new therapeutic agents has been an important aspect of chemical-biology. Herein we report a reagent-based, diversity-oriented synthetic (DOS) strategy to probe chemical and biological space via a “Click, Click, Cyclize” protocol. In this DOS approach, three sulfonamide linchpins underwent cyclization protocols with a variety of reagents to yield a collection of structurally diverse S-heterocycles. In silico analysis is utilized to evaluate the diversity of the compound collection against chemical space (PC analysis), shape space (PMI) and polar surface area (PSA) calculations.

Rolfe, Alan; Lushington, Gerald. H.

2010-01-01

79

Reagent based DOS: a "Click, Click, Cyclize" strategy to probe chemical space.  

PubMed

The synthesis of small organic molecules as probes for discovering new therapeutic agents has been an important aspect of chemical-biology. Herein we report a reagent-based, diversity-oriented synthetic (DOS) strategy to probe chemical and biological space via a "Click, Click, Cyclize" protocol. In this DOS approach, three sulfonamide linchpins underwent cyclization protocols with a variety of reagents to yield a collection of structurally diverse S-heterocycles. In silico analysis is utilized to evaluate the diversity of the compound collection against chemical space (PC analysis), shape space (PMI) and polar surface area (PSA) calculations. PMID:20401396

Rolfe, Alan; Lushington, Gerald H; Hanson, Paul R

2010-03-16

80

The Voyager program at APL  

SciTech Connect

An overview is presented of the structure and function of the Applied Physics Laboratory's low-energy charged particle (LECP) instrument used in NASA's Voyager program. The LECP experiment was designed to measure the intensity, energy spectra, composition, angular distributions, and spatial and temporal characteristics of ions and electrons that are encountered by the spacecraft. Scientific findings of previous planetary encounters are noted, and color energy-time spectrograms that summarize the LECP results at each planet are presented and analyzed. Some details of the encounter by Voyager 2 of Neptune are provided, noting that the characteristics of the trajectory that was used provided for close observation of Triton, observations of particle structures, and exploration of Neptune's polar cap. A schematic of Neptune's magnetosphere is provided and analyzed. 11 refs.

Mauk, B.H.; Keath, E.P.; Krimigis, S.M. (Johns Hopkins Univ., Laurel, MD (USA))

1990-06-01

81

Voyager color photometry of Saturn's main rings: a correction  

NASA Astrophysics Data System (ADS)

We correct a calibration error in our earlier analysis of Voyager color observations of Saturn's main rings at 14° phase angle (Estrada and Cuzzi, 1996, Icarus 122, 251) and present thoroughly revised and reanalyzed radial profiles of the brightness of the main rings in the Voyager green, violet, and ultraviolet filters and the ratios of these brightnesses. These results are consistent with more recent HST results at 6° phase angle, once allowance is made for plausible phase reddening of the rings (Cuzzi et al., 2002, Icarus 158, 199). Unfortunately, the Voyager camera calibration factors are simply not sufficiently well known for a combination of the Voyager and HST data to be used to constrain the phase reddening quantitatively. However, some interesting radial variations in reddening between 6 and 14° phase angles are hinted at. We update a ring-and-satellite color vs albedo plot from Cuzzi and Estrada (1998, Icarus 132, 1) in several ways. The A and B rings are still found to be in a significantly redder part of color-albedo space than Saturn's icy satellites.

Estrada, Paul R.; Cuzzi, Jeffrey N.; Showalter, Mark R.

2003-11-01

82

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

NASA Astrophysics Data System (ADS)

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.

1991-04-01

83

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

84

Checkout and Countdown of the Larger Space Probe Missiles  

Microsoft Academic Search

While it is obvious that missiles for different space programs carry widely different electronic equipment, it is not so apparent that missiles on the same program may carry just as wide a variety of equipment. Checkout and countdown equipment must be versatile, not only because of the variety of electronic airborne equipment, but because of the special needs of research

W. O. Campbell

1960-01-01

85

Probing Lorentz Violating (Stringy) Quantum Space-Time Foam  

NASA Astrophysics Data System (ADS)

Quantum Space Time may be characterized by a plethora of novel phenomena, such as Lorentz violations and non-trivial refractive indices, stochastic metric fluctuation effects leading to decoherence of quantum matter and non-commutativity of space-time coordinates. In string theory, which is one of the major approaches to quantum gravity, such coordinate non-commutativities arise naturally in many instances. In the talk I review one such instance, which arises in the modern context of D-brane defects in the background space time, over which string matter propagates. This serves as a prototype of space-time foam in this context. I chose this model, over many others, because it may actually have some unique features that can be falsified experimentally either by means of high-energy astrophysical observations or in some particle-interferometers, such as neutral meson factories. In particular, the model may explain the recent observations of the FERMI Gamma-Ray Telescope on delayed emission of 30 GeV photons from a distant Gamma-Ray-Burst 090510, in agreement with previous observations from the MAGIC and HESS Telescopes, but can also lead to falsifiable predictions for quantum foam effects in forthcoming upgrades of certain ``particle interferometers'', such as neutral meson factories.

Mavromatos, Nick E.

2009-12-01

86

Probing Interstellar Dust with Space-based Coronagraphs  

Microsoft Academic Search

We show that space-based telescopes such as the proposed Terrestrial Planet Finder Coronagraph will be able to detect the light scattered by the interstellar grains along lines of sight passing near stars in our Galaxy. The relative flux of the scattered light within 1\\

N. J. Turner; K. Grogan; J. B. Breckinridge

2008-01-01

87

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

88

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

89

Probing reionization with LOFAR using 21-cm redshift space distortions  

NASA Astrophysics Data System (ADS)

One of the most promising ways to study the epoch of reionization (EoR) is through radio observations of the redshifted 21-cm line emission from neutral hydrogen. These observations are complicated by the fact that the mapping of redshifts to line-of-sight positions is distorted by the peculiar velocities of the gas. Such distortions can be a source of error if they are not properly understood, but they also encode information about cosmology and astrophysics. We study the effects of redshift space distortions on the power spectrum of 21-cm radiation from the EoR using large-scale N-body and radiative transfer simulations. We quantify the anisotropy introduced in the 21-cm power spectrum by redshift space distortions and show how it evolves as reionization progresses and how it relates to the underlying physics. We go on to study the effects of redshift space distortions on LOFAR observations, taking instrument noise and foreground subtraction into account. We find that LOFAR should be able to directly observe the power spectrum anisotropy due to redshift space distortions at spatial scales around k ˜ 0.1 Mpc-1 after ?1000 h of integration time. At larger scales, sample errors become a limiting factor, while at smaller scales detector noise and foregrounds make the extraction of the signal problematic. Finally, we show how the astrophysical information contained in the evolution of the anisotropy of the 21-cm power spectrum can be extracted from LOFAR observations, and how it can be used to distinguish between different reionization scenarios.

Jensen, Hannes; Datta, Kanan K.; Mellema, Garrelt; Chapman, Emma; Abdalla, Filipe B.; Iliev, Ilian T.; Mao, Yi; Santos, Mario G.; Shapiro, Paul R.; Zaroubi, Saleem; Bernardi, G.; Brentjens, M. A.; de Bruyn, A. G.; Ciardi, B.; Harker, G. J. A.; Jeli?, V.; Kazemi, S.; Koopmans, L. V. E.; Labropoulos, P.; Martinez, O.; Offringa, A. R.; Pandey, V. N.; Schaye, J.; Thomas, R. M.; Veligatla, V.; Vedantham, H.; Yatawatta, S.

2013-10-01

90

Probing Interstellar Dust With Space-Based Coronagraphs  

Microsoft Academic Search

We show that space-based telescopes such as the proposed Terrestrial Planet\\u000aFinder Coronagraph will be able to detect the light scattered by the\\u000ainterstellar grains along lines of sight passing near stars in our Galaxy. The\\u000arelative flux of the scattered light within one arcsecond of a star at 100 pc\\u000ain a uniform interstellar medium of 0.1 H atoms

N. J. Turner; K. Grogan; J. B. Breckinridge

2008-01-01

91

46 CFR 42.05-45 - International voyage.  

Code of Federal Regulations, 2011 CFR

...of the 1966 Convention, an international voyage means a sea voyage...every territory for the international relations of which any specific Contracting...considered as being on an international voyage for the purpose...

2011-10-01

92

Probing Interstellar Dust with Space-based Coronagraphs  

NASA Astrophysics Data System (ADS)

We show that space-based telescopes such as the proposed Terrestrial Planet Finder Coronagraph will be able to detect the light scattered by the interstellar grains along lines of sight passing near stars in our Galaxy. The relative flux of the scattered light within 1" of a star at 100 pc in a uniform interstellar medium of 0.1 H atoms cm-3 is about 10-7. The halo increases in strength with the distance to the star and is unlikely to limit the coronagraphic detection of planets around the nearest stars. Grains passing within 100 AU of Sun-like stars are deflected by radiation, gravity, and magnetic forces, leading to features in the scattered light that can potentially reveal the strength of the stellar wind, the orientation of the stellar magnetic field and the relative motion between the star and the surrounding interstellar medium.

Turner, N. J.; Grogan, K.; Breckinridge, J. B.

2008-07-01

93

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

94

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

95

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

96

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

97

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

NASA Astrophysics Data System (ADS)

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.

2012-05-01

98

What Voyager SAW - Jupiter's dazzling realm  

NASA Astrophysics Data System (ADS)

The paper examines recent findings of the Voyager I and Voyager II satellites, including information concerning Jupiter's moons and their atmospheres. Various illustrations and photographs are presented that indicate intriguing features of Io, Europa, Ganymede, and Callisto. Among the discoveries is the witnessing of a volcanic eruption on Io's surface, indicating existing molecular structures.

Gore, R.

1980-01-01

99

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

100

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

Microsoft Academic Search

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.

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

1982-01-01

101

Galactically inertial space probes for the direct measurement of the metric expansion of the universe  

NASA Astrophysics Data System (ADS)

Astrometric data from the future GAIA and OBSS missions will allow a more precise calculation of the local galactic circular speed, and better measurements of galactic movements relative to the CMB will be obtained by post-WMAP missions (ie Planck). Contemporary development of high specific impulse electric propulsion systems (ie VASIMIR) will enable the development of space probes able to properly compensate the galactic circular speed as well as the resulting attraction to the centre of our galaxy. The probes would appear immobile to an ideal observer fixed at the centre of the galaxy, in contrast of every other galactic object, which would appear moving according to their local galactic circular speed and their proper motions. Arranging at least three of these galactically static probes in an extended formation and measuring reciprocal distances of the probes over time with large angle laser ranges could allow a direct measurement of the metric expansion of the universe. Free-drifting laser-ranged targets released by the spacecrafts could also be used to measure and compensate solar system's induced local perturbations. For further reducing local effects and increase the accuracy of the results, the distance between the probes should be maximized and the location of the probes should be as far as possible from the Sun and any massive object (ie Jupiter, Saturn). Gravitational waves could also induce random errors but data from GW observatories like the planned LISA could be used to correct them.

Cagnani, Ivan

2011-02-01

102

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

103

The Atmosphere of Jupiter from Voyager's and Cassini's Infrared Observations  

NASA Astrophysics Data System (ADS)

We perform a comparative study of the structure of Jupiter's troposphere and low stratosphere based on the analysis of the Voyager/IRIS and the Cassini/CIRS observations of the Jovian infrared emission. Our results show changes in the zonal mean properties of the atmosphere, which are probably related to seasonal effects. These changes are consistent with the changed appearance of the planet at visible wavelengths. We use the brightness temperature of Jupiter at 1392 cm-1 (7.18 ? m) to determine the depth of the top cloud layer in the Jovian troposphere and an ammonia ice indicator ? =TB(? =1040) -TB(? =1060) (Wong et al. 2004) to look for correlations with the derived cloud structure. The results from the analysis of the Voyager/IRIS observations are compared with the atmospheric opacity of the atmosphere at 5 ? m and 45 ? m derived from the same data set (Conrath and Gierasch 1986). We perform a similar analysis for the structure of the Great Red Spot and map the cloud opacity, the temperature and the alpha parameter in the vicinity of the GRS. Conrath, B. J, and P. J. Gierasch 1986. Retrieval of ammonia abundances and cloud opacities on Jupiter from Voyager IRIS spectra. Icarus v. 67, p. 444-455. Wong, M. H, G. L. Bjoraker, M. D. Smith, F. M. Flasar, C. A. Nixon 2004. Identification of the 10-micron ammonia ice feature on Jupiter. Planetary and Space Science, v. 52, p. 385-395.

Matcheva, K. I.; Gierasch, P. J.; Conrath, B. J.

2005-08-01

104

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. Falličs; M. Mahdieh; T. A. Hall; P. Audebert; J.-P. Geindre; J.-C. Gauthier; A. Mysyrowicz; G. Grillon; A. Antonetti

1996-01-01

105

Heavy Neutral Beam Probe Development and Space Poten tial Measurements of Helimak  

NASA Astrophysics Data System (ADS)

The Heavy Neutral Beam Probe (HNBP) is an extension of the Heavy Ion Beam Probe that can probe plasmas with low electron temperature and densities. The HNBP's beam operates at U˜10,eV, and the probing ions, Na, are neutralized in a Cs based neutralizer. Even with Na neutrals, the signal current is low (tens of nanoAmperes), and so a phase sensitive detection system is used to raise low frequency signals out of the noise by modulating the neutral Na beam. The HNBP has been specifically developed for measuring the Helimak plasma device, which is an approximation to the infinite cylindrical slab with open field lines. We will present measurements of the plasma potential accross magnetic field lines and along the direction of various gradients including density, temperature, and magnetic field strength gradients. These are the first space potential measurements of a plasma of electron temperature below Te˜40,V; the Helimak's HNBP is extending beam probing to the Te˜10,V regime.

Garcia de Gorordo, Alvaro; Hallock, Gary A.; Gentle, Kenneth W.

2011-11-01

106

Voyager 2 and the Uranian rings  

SciTech Connect

Voyager 2 data on the Uranian disk system are presented and examined. The disk system consists of nine narrow rings, ranging in width from a few km to about 100 km. The Uranian rings are eccentric, inclined to the planet's equatorial plane, and precessing. The Uranian ring characteristics detected in the Voyager data are described and compared with those of the Saturn rings. The origin and maintenance of the rings are discussed, and the particle distribution in the ring system is studied.

Porco, C.C.

1986-12-01

107

Design of triads for probing the direct through space energy transfers in closely spaced assemblies.  

PubMed

Using a selective stepwise Suzuki cross-coupling reaction, two trimers built on three different chromophores were prepared. These trimers exhibit a D(^)A1-A2 structure where the donor D (octa-?-alkyl zinc(II)porphyrin either as diethylhexamethyl, 10a, or tetraethyltetramethyl, 10b, derivatives) through space transfers the S1 energy to two different acceptors, di(4-ethylbenzene) zinc(II)porphyrin (A1; acceptor 1) placed cofacial with D, and the corresponding free base (A2; acceptor 2), which is meso-meso-linked with A1. This structure design allows for the possibility of comparing two series of assemblies, 9a,b (D(^)A1) with 10a,b (D(^)A?1-A2), for the evaluation of the S1 energy transfer for the global process D*?A2 in the trimers. From the comparison of the decays of the fluorescence of D, the rates for through space energy transfer, kET for 10a,b (kET ? 6.4 × 10(9) (10a), 5.9 × 10(9) s(-1) (10b)), and those for the corresponding cofacial D(^)A1 systems, 9a,b, (kET ? 5.0 × 10(9) (9a), 4.7 × 10(9) s(-1) (9b)), provide an estimate for kET for the direct through space D*?A2 process (i.e., kET(D(^)A1-A2) - kET(D(^)A1) = kET(D*?A2) ? 1 × 10(9) s(-1)). This channel of relaxation represents ?15% of kET for D*?A1. PMID:23844900

Camus, Jean-Michel; Aly, Shawkat M; Fortin, Daniel; Guilard, Roger; Harvey, Pierre D

2013-07-11

108

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.

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

109

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

110

Voyager planetary radio astronomy studies  

NASA Astrophysics Data System (ADS)

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.

1993-12-01

111

Temporal fluctuations in the bosonic Josephson junction as a probe for phase space tomography  

NASA Astrophysics Data System (ADS)

We study the long-time dynamics of the reduced one-particle Bloch vector S of a two-mode Bose-Hubbard model in the Josephson interaction regime, as a function of the relative phase and occupation imbalance of an arbitrary coherent preparation. We find that the variance of the long-time fluctuations of S can be factorized as a product of the inverse participation number 1/M that depends only on the preparation, and a semiclassical function C(E) that reflects the phase space characteristics of the pertinent observable. Temporal fluctuations can thus be used as a sensitive probe for phase space tomography of quantum many-body states.

Khripkov, Christine; Cohen, Doron; Vardi, Amichay

2013-04-01

112

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

113

Measurement of electron temperatures in the lower ionosphere by detecting the space potential on the langmuir probe characteristic  

Microsoft Academic Search

Electron temperatures have been determined at Thumba on Nike Apache flight 10.11 (12 March 1967, 1857 hr IST) by the usual retarding potential analysis and by using an a.c. modulation technique for detecting the space potential on the Langmuir probe characteristic. Simultaneous measurements with the two techniques show that the space potential technique gives temperatures which are related to the

B. H. Subbaraya; Satya Prakash; S. P. Gupta; H. S. S. Sinha

1974-01-01

114

Measurement of electron temperatures in the lower ionosphere by detecting the space potential on the Langmuir probe characteristic  

Microsoft Academic Search

Electron temperatures have been determined at Thumba on Nike Apache ; flight 10.11 (March 12, 1967, 1857 hr IST) by the usual retarding potential ; analysis and by using an ac modulation technique for detecting the space ; potential on the Langmuir probe characteristic. Simultaneous measurements with ; the two techniques show that the space potential technique gives temperatures ;

B. H. Subbaraya; S. Prakash; S. P. Gupta; H. S. S. Sinha

1974-01-01

115

Observations of the Jovian UV aurora by Voyager  

NASA Astrophysics Data System (ADS)

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, F.; Sandel, B. R.; Broadfoot, A. L.

1987-04-01

116

Space-resolved fluorescence spectroscopic measurements with an optical fiber probe  

NASA Astrophysics Data System (ADS)

By monitoring of the emitted signal from a sample while varying the excitation wavelength, emission wavelength or both of them, fluorescence spectroscopy has become a powerful diagnostic technology. Fluorescence spectrometers can be used to measure and record the fluorescence spectra of a given sample, and have been successfully applied in different areas including biology, biochemistry, chemistry, medicine, environmental science, material science, food industry, and pharmaceutical industry. In order to increase the flexibility and applicability of conventional fluorescence spectrometers, we design an optic fiber probe for conducting the UV/Vis excitation light to a sample under study, and for collecting the fluorescence produced by the sample. Different excitation/emission fiber bundle arrangements have been fabricated and their performances have been evaluated and compared. Fiber adaptors which can be used for different commercial fluorescence spectrometers are also developed. In order to achieve space-resolved fluorescence spectroscopic measurements, we connect the fiber probe to a microscope which is mounted on a 3D traverse stage. Experiments and measurement results using the space-resolved fiber optic fluorescence spectrometer are presented in this paper.

Li, Enbang; Qiu, Hialin

2008-12-01

117

46 CFR 175.120 - Vessels on an international voyage.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Vessels on an international voyage. 175.120 Section 175...PROVISIONS § 175.120 Vessels on an international voyage. A mechanically propelled...carries more than 12 passengers on an international voyage must comply with the...

2011-10-01

118

46 CFR 188.10-35 - International voyage.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false International voyage. 188.10-35 Section...This Subchapter § 188.10-35 International voyage. (a) This section describes...voyages which are considered to be âinternational voyagesâ for the purposes of...

2011-10-01

119

Radio science with voyager at jupiter: initial voyager 2 results and a voyager 1 measure of the io torus.  

PubMed

Voyager 2 radio signals were observed essentially continuously during a grazing occultation of the spacecraft by the southern limb of Jupiter. Intensity data show a classic atmospheric occultation profile and the effects of turbulence and ionospheric focusing and defocusing. No reliable profile of the neutral atmosphere has yet been obtained, primarily because of a combination of large trajectory uncertainties and error multiplication effects associated with the grazing geometry of the Voyager 2 occultation. Analysis of the dispersive ionospheric refraction data yields preliminary profiles for the topside ionosphere at 66.7 degrees S (entry in the evening) and 50.1 degrees S (exit in the morning) that are reversed with respect to corresponding Voyager 1 profiles in terms of plasma concentration at a fixed altitude. Plasma scale heights and temperatures of 880 kilometers, 1200 K and 1040 kilometers, 1600 K were obtained for morning and evening conditions, respectively. Preliminary reduction of the pre-encounter occultation of Voyager 1 by the Io torus yields an average plasma density of about 1000 electrons per cubic centimeter. PMID:17733914

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

1979-11-23

120

Redshift-space distortions in deep redshift surveys as a probe of the invisible Universe  

NASA Astrophysics Data System (ADS)

Massive redshift surveys of galaxies beyond the local Universe (i.e.z>0.3) provide an exhaustive probe of the observed acceleration of cosmic expansion. While they have the ability to measure the expansion history H(z) through Baryonic Acoustic Oscillations in the galaxy power spectrum, they can at the same time probe f(z) using the redshift-space distortions introduced in the observed clustering pattern by galaxy peculiar motions. Coupling these two measurements one can in principle distinguish whether cosmic acceleration is due to a new form of `dark energy' in the cosmic budget, or rather requires a modification of General Relativity. These two radically alternative scenarios are degenerate when considering H(z) alone, as yielded, e.g., by the Hubble diagram of Type Ia supernovae. We review our recent measurements of redshift distortions at z~ 1 based on the VIMOS VLT Deep Survey ``Wide'' data and discuss the revived interest on this technique in the context of dark energy. Current results are consistent with the simplest cosmological-constant scenario, but error bars are still too large to rule out alternative models. Forecasts based both on extensive simulations and Fisher-matrix computations, show that next-generation deep surveys optimizing the combination of large volumes and good galaxy sampling will be able to use redshift distortions as a key tool to understand the physical origin of cosmic acceleration. Among these, we introduce the newly started VIMOS Public Extragalactic Redshift Survey (VIPERS) at the ESO VLT, which is building at ~0.8 a sample comparable to current local redshift surveys (105 redshifts in a volume 5×107 h-1 Mpc3). Finally, we provide an example of the exquisite accuracy that could be reached on measurements of redshift-space distortions (among many others), with a massive 20,000 deg2 near-infrared spectroscopic survey from space, as foreseen by the EUCLID mission for the ESA `Cosmic Vision' program.

Guzzo, Luigi; Le Fčvre, Olivier

2010-06-01

121

Outer Planets\\/Solar Probe Project: Solar Probe  

Microsoft Academic Search

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 \\

B. T. Tsurutani

2000-01-01

122

Electron density of local interstellar medium, based on the Voyager heliospheric-shock observations  

SciTech Connect

Some implications of a model for the solar wind-local-interstellar-medium (LISM) interaction, comprising a bow shock and a heliospheric shock with a contact interface in between, are compared against the Voyager probe data. A fit can be achieved if the LISM electron density is somewhat higher than indicated by pulsar dispersion measurements. The theory is compatible with the hydrogen densities inferred from Copernicus and from the scattering solar L-alpha radiation. 14 references.

Baranov, V.B.

1986-10-01

123

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

124

Voyager flight engineering - Preparing for Uranus  

NASA Astrophysics Data System (ADS)

Two Voyager spacecraft are currently engaged in exploration of the outer solar system with Voyager 2 scheduled to conduct the first close-up investigation of the planet Uranus during the period November 4, 1985 through March 3, 1986. Flight engineering for the Voyager project has the objectives of delivering a functioning spacecraft containing observing sequences to the right places at the right times. Due to the changing environment as the mission has progressed outward from Jupiter to Saturn to Uranus (and on to Neptune), this engineering task has included the development of significant new capabilities. The paper utilizes the case-study method to examine some new spacecraft capabilities in three subsystems: data, attitude and articulation control, and power. The implementation of a new navigational data-type, delta DOR, is also reviewed. An overview is given of the Voyager sequencing process for the cruise and encounter phases with a case study focusing on late updating of part of the near encounter sequence. The prospective mission to Neptune is previewed.

McLaughlin, W. I.; Wolff, D. M.

1985-01-01

125

New Voyager Radio Spectrograms of Uranus.  

National Technical Information Service (NTIS)

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 the...

W. Calvert D. Tsintikidis

1990-01-01

126

The Second Voyage of the Mimi.  

ERIC Educational Resources Information Center

This book includes 12 units that have been adapted from the television series "Voyage of the Mimi." Each unit includes the episode, an activity, and an expedition. The episodes introduce and accompany each episode of the television series. The activity is an extension of that episode which can be done in the classroom. Mapping skills, foreign…

Bank Street Coll. of Education, New York, NY.

127

Saturn's small satellites - Voyager imaging results  

Microsoft Academic Search

Voyagers 1 and 2 provided images of sufficient resolution for morphologic and photometric studies of Saturn's small satellites. These objects, all very difficult to observe from earth, orbit Saturn at distances of 2.3 to 6.3 Saturn radii (just outside the A ring to the orbit of Dione) and range in mean diameter from 22 to 188 km. All are irregularly

P. Thomas; J. Veverka; D. Morrison; M. Davies; T. V. Johnson

1983-01-01

128

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

129

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.

130

Enabling interstellar probe  

Microsoft Academic Search

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

Ralph L. McNutt Jr.; Robert F. Wimmer-Schweingruber

2011-01-01

131

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

NASA Astrophysics Data System (ADS)

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.

2013-08-01

132

Emissive probe diagnostics in low temperature plasma--effect of the space charge and variations of the electron saturation current  

SciTech Connect

We report on the effect of over{approx}underestimation of the plasma potential by the strongly emitting probe technique in the low temperature plasma due to the effect of the space charge of the emitted electrons; experimental data are compared with theoretical model. Further we studied the electron saturation current variations at varying probe heating and we found them to be closely related to the probe wire contamination. The study was performed in two types of low temeperature argon plasma--weakly magnetized plasma of the cylindrical magnetron and the hollow cathode plasma jet showing different trends.

Marek, A.; Jilek, M.; Pickova, I.; Kudrna, P.; Kluson, J.; Kolpakova, A.; Tichy, M. [Faculty of Mathematics and Physics, Charles University in Prague, V Holesovickach 2, 180 00 Prague (Czech Republic)

2008-03-19

133

Scalar field probes of power-law space-time singularities  

NASA Astrophysics Data System (ADS)

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 inverse square behaviour ~ x-2 in the ``tortoise coordinate'' x provided that the metrics satisfy the strict Dominant Energy Condition (DEC). This result parallels that obtained in [1] 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.

Blau, Matthias; Frank, Denis; Weiss, Sebastian

2006-08-01

134

Probing Real-Space and Time-Resolved Correlation Functions with Many-Body Ramsey Interferometry  

NASA Astrophysics Data System (ADS)

We propose to use Ramsey interferometry and single-site addressability, available in synthetic matter such as cold atoms or trapped ions, to measure real-space and time-resolved spin correlation functions. These correlation functions directly probe the excitations of the system, which makes it possible to characterize the underlying many-body states. Moreover, they contain valuable information about phase transitions where they exhibit scale invariance. We also discuss experimental imperfections and show that a spin-echo protocol can be used to cancel slow fluctuations in the magnetic field. We explicitly consider examples of the two-dimensional, antiferromagnetic Heisenberg model and the one-dimensional, long-range transverse field Ising model to illustrate the technique.

Knap, Michael; Kantian, Adrian; Giamarchi, Thierry; Bloch, Immanuel; Lukin, Mikhail D.; Demler, Eugene

2013-10-01

135

Probing real-space and time-resolved correlation functions with many-body ramsey interferometry.  

PubMed

We propose to use Ramsey interferometry and single-site addressability, available in synthetic matter such as cold atoms or trapped ions, to measure real-space and time-resolved spin correlation functions. These correlation functions directly probe the excitations of the system, which makes it possible to characterize the underlying many-body states. Moreover, they contain valuable information about phase transitions where they exhibit scale invariance. We also discuss experimental imperfections and show that a spin-echo protocol can be used to cancel slow fluctuations in the magnetic field. We explicitly consider examples of the two-dimensional, antiferromagnetic Heisenberg model and the one-dimensional, long-range transverse field Ising model to illustrate the technique. PMID:24138270

Knap, Michael; Kantian, Adrian; Giamarchi, Thierry; Bloch, Immanuel; Lukin, Mikhail D; Demler, Eugene

2013-10-04

136

Rossi and Space Physics  

NASA Astrophysics Data System (ADS)

The beginning of the Space Age opened a new realm of exploration and Bruno Rossi immediately focused on devising an instrument for studying the interplanetary environment. The modulated Faraday cup that he and his colleagues developed was launched on Explorer X on March 21, 1961. Although the lifetime of the battery-powered spacecraft was only 60 hours, that was long enough for the MIT plasma probe to reveal a hot, supersonic solar wind flowing along the flank of the Earth's magnetosphere. The legacy of that first short flight now extends outward on a 34-year journey to 98 AU where the plasma probe on Voyager 2 measures the deflection of the subsonic wind as it approaches the outer frontier of the heliosphere and contact with the interstellar plasma outside. Over the coming decade that legacy will extend inward to within 0.05 AU of the Sun as the plasma probe on Solar Probe Plus explores the region near the inner frontier and the source of the supersonic solar wind. The exploration of the solar wind from near its beginning outward to its end will be a lasting tribute to Bruno Rossi's contributions to Space Physics.

Stone, Edward

2012-03-01

137

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.

Ajami, Dariush; Iwasawa, Tetsuo; Rebek, Julius

2006-01-01

138

Voyager 2 radio observations of uranus.  

PubMed

Within distances to Uranus of about 6 x 10(6) kilometers (inbound) and 35 x 10(6) kilometers (outbound), the planetary radio astronomy experiment aboard Voyager 2 detected a wide variety of radio emissions. The emission was modulated in a period of 17.24 +/- 0.01 hours, which is identified as the rotation period of Uranus' magnetic field. Of the two poles where the axis of the off-center magnetic dipole (measured by the magnetometer experiment aboard Voyager 2) meets the planetary surface, the one closer to dipole center is now located on the nightside of the planet. The radio emission generally had maximum power and bandwidth when this pole was tipped toward the spacecraft. When the spacecraft entered the nightside hemisphere, which contains the stronger surface magnetic pole, the bandwidth increased dramatically and thereafter remained large. Dynamically evolving radio events of various kinds embedded in these emissions suggest a Uranian magnetosphere rich in magnetohydrodynamic phenomena. PMID:17812898

Warwick, J W; Evans, D R; Romig, J H; Sawyer, C B; Desch, M D; Kaiser, M L; Alexander, J K; Carr, T D; Staelin, D H; Gulkis, S; Poynter, R L; Aubier, M; Boischot, A; Leblanc, Y; Lecacheux, A; Pedersen, B M; Zarka, P

1986-07-01

139

Ultimate Challenge Voyage for Fremantle medicine students  

Microsoft Academic Search

Eight 1st year medicine students from The University of Notre Dame Australia’s Fremantle Campus participated in a five day voyage on the STS Leeuwin II in late November as part of the social justice component of their studies. Their role was to assist and support 28 participants with special physical or intellectual limitations.\\u000aAs part of their experience they were

Michelle Ebbs

2008-01-01

140

Probing gravity in interplanetary space: combined use of ISA accelerometer and next-generation tracking  

NASA Astrophysics Data System (ADS)

The Solar System is a complex laboratory for testing gravitational physics. Indeed, its scale and hierarchical structure make possible a wide range of tests for gravitational theories, studying the motion of both natural and artificial objects and comparing the predictions of different theories with experimental data. Future exploration scenarios show the possibility of placing deep-space probes near the Sun or in outer Solar System, thereby extending the range of conditions in which to test directly the theories. In particular, the Sun-Earth-Moon is the most accurately known gravitational three-body laboratory, which is undergoing a new, strong wave of research and robotic exploration. In addition, the benefits of a synergetic study of planetary science and gravitational physics are of the greatest importance (as shown by the success of the Apollo program), especially in the Earth-Moon (for example with the proposed International Lunar Network, ILN), Mars-Phobos, Jovian and Saturnian sub-systems. The availability of high-quality tracking data, to be fitted by suitable dynamic models for the spacecraft dynamics, opens critical issues regarding the quality of these models, i.e. their capability of fitting data without an excessive number of empirical hypotheses. A typical case is represented by the non-gravitational phenomena, often relevant, which in general are difficult to model. More generally, gravitation tests with Lunar Laser Ranging, inner or outer Solar System probes and the appearance of the so-called "anomalies"(like the one indicated by the Pioneers), whatever their real origin (either instrumental effects or due to new physics), show the necessity of a coordinated improvement of tracking and modelization techniques. A number of steps in this directions will be discussed, employing the use of high-sensitivity accelerometers like ISA (Italian Spring Accelerometer) — in order to measure directly non-gravitational effects — and combined microwave and laser tracking, for an efficient tracking of deep-space test masses. A case study will be presented: a multi-spacecraft mission proposal for planetary exploration and fundamental physics.

Peron, Roberto; Peron, R.; Bellettini, G.; Berardi, S.; Boni, A.; Cantone, C.; Coradini, A.; Currie, D. G.; Dell'Agnello, S.; Delle Monache, G. O.; Fiorenza, E.; Garattini, M.; Iafolla, V.; Intaglietta, N.; Lefevre, C.; Lops, C.; March, R.; Martini, M.; Nozzoli, S.; Patrizi, G.; Porcelli, L.; Reale, A.; Santoli, F.; Tauraso, R.; Vittori, R.

141

Concept Considerations for a Deep Space Gravity Probe Based on Laser-Controlled Free-Flying Reference Masses  

NASA Astrophysics Data System (ADS)

Concept considerations for a space mission with the objective of precisely testing the gravitational motion of a small test mass in the solar system environment are presented. In particular, the mission goal is an unambiguous experimental verification or falsification of the Pioneer anomaly effect. A promising concept is featuring a passive reference mass, shielded or well modeled with respect to nongravitational accelerations and formation flying with a rather standard deep space probe. The probe provides laser ranging and angular tracking to the reference mass, ranging to Earth via the radio-communication link and shielding from light pressure in the early parts of the mission. State-of-the-art ranging equipment can be used throughout, but requires in part optimization to meet the stringent physical budget constraints of a deep space mission. Mission operation aspects are briefly addressed.

Johann, Ulrich A.

142

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

143

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

PubMed

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. PMID:21033993

Demidov, V I; Koepke, M E; Raitses, Y

2010-10-01

144

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

145

Report on the Conference Future Ground-based Solar System Research: Synergies with Space Probes and Space Telescopes  

Microsoft Academic Search

An interdisciplinary workshop bringing together Solar System researchers, space mission engineers and scientists, ground- and space-based observers and theoreticians is summarised. The broad scope of the meeting covered current and future space missions, planned ground-based facilities and their closer interaction.

Hans Ulrich Käufl; Gian Paolo Tozzi

2008-01-01

146

46 CFR 180.10 - Applicability to vessels on an international voyage.  

Code of Federal Regulations, 2011 CFR

... false Applicability to vessels on an international voyage. 180.10 Section 180.10...180.10 Applicability to vessels on an international voyage. A vessel on an international voyage subject to the...

2011-10-01

147

Comparison of initial cassini/lemms and voyager 1 and 2 low energy charged particle trapped radiation observations  

NASA Astrophysics Data System (ADS)

Voyager 1 and 2 observations with the Low Energy Charged Particle instrument were used to optimize the design of the Cassini/MIMI/LEMMS instrument. Hence, initial studies of LEMMS observations during Jupiter approach and SOI will include reconciliation of the Cassini and Voyager fluxes and energy spectra of energetic electrons and ions from about 20 keV up to several MeV for electrons and from about 30 keV up to 50 MeV for protons. Predicted Cassini trajectory and modeled magnetic field will be used to establish a physical basis from comparison. Of special interest will be the values of phase space densities (PSDs) at identical values of first, second and third invariants. Voyager observed departures from the radial variation of PSDs expected for loss-free inward radial diffusion that were interpreted as distributed losses and an suggesting an interior source. This speculations will be evaluated against the initial Cassini LEMMS observations.

Armstrong, T.; Manweiler, J.; Krupp, N.; Livi, S.; Krimigis, S.; Mitchell, D.; Lanzerotti, L.

148

Voyager 2 investigates the atmosphere of Uranus  

SciTech Connect

The composition and structure of the Uranian atmosphere, as determined from Voyager data, are described. It is observed that the atmosphere contains He, CH/sub 4/, C/sub 2/H/sub 2/, HD, CH/sub 3/D, and NH/sub 3/; it has an effective temperature of -216 C; it is tilted 98 deg to the plane of the ecliptic; and the atmospheric temperature varies due to the location of the axis of rotation. Consideration is given to the clouds in the violet and orange light and the CH/sub 4/ wavelength; the motion of the weather systems; and the electroglow of the magnetosphere.

Hunt, G.

1986-12-01

149

Io plasma torus electrons - Voyager 1  

NASA Astrophysics Data System (ADS)

A thermal Maxwellian component of the electron distribution function, together with a suprathermal, non-Maxwellian one, are featured in the present analysis of in situ plasma electron observations made by the Voyager 1 plasma science experiment in the Io plasma torus. A large difference in the hot electron pressure P(H) is noted between the inbound and the outbound data; this is interpreted as a latitudinal gradient, with P(H) being maximum at the magnetic equator. The presence of a neutral corona around Io is inferred from the observed decrease and symmetry with respect to Io of the cold electron temperature.

Sittler, E. C.; Strobel, D. F.

1987-06-01

150

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.

151

Voyager Finds Magnetic Foam at Solar System's Edge  

NASA Video Gallery

The Voyager satellites are now traveling through the outer edge of the solar system, called the heliosheath. Using a computer model based on Voyager data, scientists have shown that the sun's magnetic field becomes bubbly in this region due to reconnection. Because of this, cosmic rays must slowly work their way through the magnetic foam before continuing on toward the sun.

gsfcvideo

2011-06-09

152

The VOYAGER speech understanding system: preliminary development and evaluation  

Microsoft Academic Search

Early experience with the development of the MIT VOYAGER spoken language system is described, and its current performance is documented. The three components of VOYAGER, the speech recognition component, the natural language component, and the application back-end, are described

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

1990-01-01

153

Voyager photopolarimeter observations of Saturn and Titan  

NASA Astrophysics Data System (ADS)

The Voyager 2 photopolarimeter experiment observed the intensity and polarization of scattered sunlight from the atmospheres of Saturn and Titan in the near-UV at 2640 A and in the near-IR at 7500 A. Measurements of Saturn's limb brightening and polarization at several phase angles up to 70 deg indicate that a significant optical depth of UV absorbers are present in the top 100 mbar of Saturn's atmosphere in the equatorial zone and north polar region, and possibly at other latitudes as well. UV absorbers are prominent in polar regions, suggesting that charged particle precipitation from the magnetosphere may be important in their formation. The whole-body polarization of Titan is strongly positive in both the UV and near IR. If spherical particles are responsible for the polarization, no single size distribution or refractive index can account for the polarization at both wavelengths. The model atmosphere proposed by Tomasko and Smith (1982), characterized by a gradient in particle size with altitude, seems capable of explaining the Voyager observations.

West, R. A.; Hord, C. W.; Simmons, K. E.; Hart, H.; Esposito, L. W.; Lane, A. L.; Pomphrey, R. B.; Morris, R. B.; Sato, M.; Coffeen, D.

154

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

155

[Pharmaceutical care for international voyagers: prophylaxis including chloroquine plus proguanil].  

PubMed

A pharmacotherapeutic follow-up of 42 voyagers prescribed with antimalarial chemoprophylaxis including chloroquine plus proguanil was performed. A report-based retrospective study showed 69% of chemoprophylaxis compliance. Adverse effects related to this type of medication would develop in 33% of voyagers. Adverse effects most commonly detected were mainly mild to moderate gastrointestinal (28.5% of voyagers) events. Resulting data are consistent with the safety profile of the chloroquine/proguanil combination as established in the international literature. It is concluded that antimalarial chemoprophylaxis should be initiated at 15 days before departure when prolonged stays are expected, so that potential adverse effects may be detected beforehand. PMID:15101806

Hernández Tintorer, J L; Lorduy Osés, L

156

Soviet space  

NASA Astrophysics Data System (ADS)

A profusely illustrated history of the Soviet space program is presented. The topics addressed include: early Soviet rockets, satellites and planetary probes, cosmonauts in space, space stations, international cooperation in space, and the Soviet space program today and tomorrow.

Miller, Jay

157

Spectrophotometric probe  

DOEpatents

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

158

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

159

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

Range, Shannon K'doah; Mullins, Jennifer

160

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

161

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

162

Voyager's discoveries mount on final rush to Neptune  

SciTech Connect

On its final approach to Neptune, Voyager 2 detected not only two new moons, designated 1989N5 and 1989N6, but shadows cast by high cyrrus-type clouds on a lower cloud deck in the planet's south polar region. Voyager scientists have also been carefully watching for massive features in Neptune's unexpectedly dynamic atmosphere; such similarities were noted between Jupiter's Great Red Spot and Neptune's Great Dark Spot, a feature comparable to the earth in size, as a 20-22 deg south latitude location. Voyager is programmed to fly about 25,000 miles above Triton on its way out of the plane of the ecliptic. Voyager will be imaging Triton during the end of a 100-year cycle in which its south pole has been subjected to increased solar heating.

Smith, B.A.

1989-08-01

163

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

164

Ultrahigh-Energy Photons as Probes of Lorentz Symmetry Violations in Stringy Space-Time Foam Models  

SciTech Connect

The time delays between {gamma} rays of different energies from extragalactic sources have often been used to probe quantum gravity models in which Lorentz symmetry is violated. It has been claimed that these time delays can be explained by or at least put the strongest available constraints on quantum gravity scenarios that cannot be cast within an effective field theory framework, such as the space-time foam, D-brane model. Here we show that this model would predict too many photons in the ultrahigh energy cosmic ray flux to be consistent with observations. The resulting constraints on the space-time foam model are much stronger than limits from time delays and allow for Lorentz violation effects way too small for explaining the observed time delays.

Maccione, Luca [DESY, Theory Group, Notkestrasse 85, D-22607 Hamburg (Germany); Liberati, Stefano [SISSA, Via Bonomea 265, 34136 Trieste (Italy); INFN, Sezione di Trieste, Via Valerio, 2, I-34127, Trieste (Italy); Sigl, Guenter [II. Institut fuer Theoretische Physik, Universitaet Hamburg, Luruper Chaussee 149, D-22761 Hamburg (Germany)

2010-07-09

165

ArcVoyager Makes ArcView Easy!  

NSDL National Science Digital Library

This site from ESRI features ArcVoyager. The program is a 50-mb package of carefully selected data, ArcView projects, and help files in a tiered format, available as free downloads in both Windows and Macintosh formats. The goal of ArcVoyager is to give students and teachers a ramped approach for developing their spatial thinking and learning how to employ ArcView tools.

Esri

166

Performance model of the Argonne Voyager multimedia server  

Microsoft Academic Search

The Argonne Voyager Multimedia Server is beingdeveloped in the Futures Lab of the Mathematics andComputer Science Division at Argonne National Laboratory.As a network-based service for recording andplaying multimedia streams, it is important that theVoyager system be capable of sustaining certain minimallevels of performance in order for it to be a viablesystem. In this article, we examine the performancecharacteristics of the

Terrence Disz; Robert Olson; Rick L. Stevens

1997-01-01

167

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

168

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.

169

Voyager observations of Jovian millisecond radio bursts  

SciTech Connect

Voyager Planetary Radio Astronomy data collected over 30-day intervals centered on the two close encounters with Jupiter were utilized to study the characteristics of millisecond-duration radio bursts (s-bursts) at frequencies between 5 and 15 MHz. In this frequency range, s-bursts are found to occur almost independently of Central Meridian Longitude and to depend entirely on the phase of Io with respect to the observer's planetocentric line of sight. Individual bursts typically cover a total frequency range of about 1.5 to 3 MHz, and they are usually strongly circularly polarized. Most bursts in a particular s-burst storm will exhibit the same polarization sense (either right-hand or left-hand), and there is some evidence for a systematic pattern in which one polarizations sense is preferred over the other as a function of Io phase and Central Meridian Longitude. These data are all suggestive of a radio source that is located along the instantaneous Io flux tube and that extends over a linear dimension of 5000 km along the field lines in both the northern and southern Hemispheres.

Alexander, J.K.; Desch, M.D.

1984-01-01

170

Voyager spacecraft images of Jupiter and Saturn  

NASA Astrophysics Data System (ADS)

The Voyager imaging system is described, noting that it is made up of a narrow-angle and a wide-angle TV camera, each in turn consisting of optics, a filter wheel and shutter assembly, a vidicon tube, and an electronics subsystem. The narrow-angle camera has a focal length of 1500 mm; its field of view is 0.42 deg and its focal ratio is f/8.5. For the wide-angle camera, the focal length is 200 mm, the field of view 3.2 deg, and the focal ratio of f/3.5. Images are exposed by each camera through one of eight filters in the filter wheel on the photoconductive surface of a magnetically focused and deflected vidicon having a diameter of 25 mm. The vidicon storage surface (target) is a selenium-sulfur film having an active area of 11.14 x 11.14 mm; it holds a frame consisting of 800 lines with 800 picture elements per line. Pictures of Jupiter, Saturn, and their moons are presented, with short descriptions given of the area being viewed.

Birnbaum, M. M.

1982-01-01

171

New Voyager radio spectrograms of Uranus  

NASA Astrophysics Data System (ADS)

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.

1990-06-01

172

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 Ĺ with 20 to 70 Ĺ resolution. A Fabry-Pérot plate gives access to higher resolution when needed. An advanced

M. Henrist; R. Duysinx; A. Monfils

1974-01-01

173

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

174

The Role Played by Space-based Probes in our Understanding of the Cosmos  

NASA Astrophysics Data System (ADS)

Over the last fifteen years a growing fleet of modern space-based astronomical telescopes has changed drastically our view of the universe. Most of these accomplishments build upon the work of ground-based astronomers over many decades, or even centuries. The combination of telescopes observing the universe at many different wavelengths has converted many prior hypotheses, for which supporting empirical data were scant, ambiguous and painfully difficult to obtain, into clearly and decisively demonstrated truth. But space observatories have gone well beyond that. In particular the Hubble Space Telescope with its combination of sharp images and deep dynamic range, has provided a detailed view of the unimagined complexity and diversity of the universe, as well as its startling beauty. It has yielded numerous surprises and raised new fundamental questions on the basic structure and laws that govern the universe. To answer these questions will require the efforts of ground-based and new space-based observatories working in combined programs over many years. In my talk I will illustrate some of the key discoveries that these space-based observatories have made such as: the deep imaging the distant universe; the calibration of the distance scale and the determination of the age of the universe; the discovery of the acceleration of the expansion rate of the universe, which requires a "dark energy" or new physics to explain it; the detection and measurement of supermassive black holes and the solution to the long standing problem of the nature of Quasars; the solution to the problem of whether Gamma Ray sources originated in our galaxy or at cosmological distances; the renewed interest in the problem of the birth of Stars and the formation of Planetary Systems; the death of Stars and the formation of supernovae, black holes and neutron stars and last but not least the exciting studies of the planets and satellites in our own dynamic solar system

Macchetto, Ferdinando Duccio

175

46 CFR 171.068 - Special considerations for Type I subdivision for vessels on short international voyages.  

Code of Federal Regulations, 2011 CFR

...Type I subdivision for vessels on short international voyages. 171.068 Section 171...Type I subdivision for vessels on short international voyages. (a) The calculations...065 for a vessel that makes short international voyages and is permitted under §...

2011-10-01

176

Voyager 2 at Neptune: Imaging science results  

SciTech Connect

Voyager 2 images of Neptune reveal a windy planet characterized by bright clouds of methane ice suspended in an exceptionally clear atmosphere above a lower deck of hydrogen sulfide or ammonia ices. Neptune's atmosphere is dominated by a large anticyclonic storm system that has been named the Great Dark Spot (GDS). About the same size as Earth in extent,the GDS bears both many similarities and some differences to the Great Red Spot of Jupiter. Neptune's zonal wind profile is remarkably similar to that of Uranus. Neptune has three major rings at radii of 42,000, 53,000, and 63,000 kilometers. The outer ring contains three higher density arc-like segments that were apparently responsible for most of the ground-based occultation events observed during the current decade. Like the rings of Uranus, the Neptune rings are composed of very dark material; unlike that of Uranus, the Neptune system is very dusty. Six new regular satellites were found, with dark surfaces and radii ranging from 200 to 25 kilometers. All lie inside the orbit of Triton and the inner four are located within the ring system. Triton is seen to be a differentiated body, with a radius of 1350 kilometers and a density of 2.1 grams per cubic centimeter; it exhibits clear evidence of early episodes of surface melting. A now rigid crust of what is probably water ice is overlain with a brilliant coating of nitrogen frost, slightly darkened and reddened with organic polymer material. Streaks of organic polymer suggest seasonal winds strong enough to move particles of micrometer size or larger, once they become airborne. At least two active plumes were seen, carrying dark material 8 kilometers above the surface before being transported downstream by high level winds. The plumes may be driven by solar heating and the subsequent violent vaporization of subsurface nitrogen.

Smith, B.A.; Croft, S.K.; Haemmerle, V.R.; Kargel, J.; Porco, C.C.; Strom, R.G. (Univ. of Arizona, Tucson (USA)); Soderblom, L.A.; Kirk, R.; Masursky, H.; McEwen, A.; Shoemaker, E.M. (Geological Survey, Flagstaff, AZ (USA)); Banfield, D.; Danielson, G.E.; DeJong, E.; Howell, C.; Ingersoll, A.P.; Schwartz, J. (California Institute of Technology, Pasadena (USA)); Barnet, C.; Beebe, R.F.; Kuehn, D.I. (New Mexico State Univ., Las Cruces (USA)); Basilevsky, A.T. (Vernadsky Institute for Cosmochemistry, Moscow (USSR)); Bollinger, K.; Brown, R.H.; Collins, Crisp, D.; Goguen, J.; Hammel, H.; Hansen, C.J.; Johnson, T.V.; Owen, W.; Rudy, D.; Synnott, S.P.; Terrile, R.J. (Jet Propulsion Laboratory, Pasadena, CA (USA)); Boyce, J.M.; Briggs, G.A. (NASA Headquarters, Washington, DC (USA)); Brahic, A.; Grenier, I.; Sicardy, B. (Observatoire de Paris (France)); Chyba, C.; Helfenstein, C.P.; Sagan, C.; Simonelli, D.; Thomas, P.; Thompson, W.R.; Veverka, J.; Verbiscer, A. (Cornell Univ., Ithaca,

1989-12-15

177

Disturbances observed near Ganymede by Voyager 2  

SciTech Connect

We investigated disturbances in the field and particle environment observed by Voyager 2 as it passed near the Jovian moon Ganymede in Jupiter's magnetosphere. The plasma analyzer observed at least a dozen sharply bounded depressions in density (cavities). We estimated that they probably extended at least 20 RGAMMA along the ambient magnetic field lines (R/sub G/=2635 km is the radius of Ganymede) and between 2--50 R/sub G/ in the directions transverse to B. Depressions in the magnetic field strength of the order of 5% of the ambient field strength (60nT to 135nT) were observed at the boundaries of the cavities in more than half of the cases; they were probably produced by currents flowing transverse to B on the boundaries. In some cases, the magnetic field strength inside the cavities was a few percent higher than the ambient value. This gives an upper limit on ..beta..=nkT/(B/sup 2//8..pi..) outside the cavities, viz. Beta<0.2; inmost cases ..beta.. was appreciably smaller than this. The flux of >2.5 MeV protons was strongly anti-correlated with the plasma density, the flux being higher inside the cavities than outside. One possible mechanism for the production of these flux enhancements and the cavities themselves is a local, magnetic field-aligned electric field, E. It is possible that Ganymede is responsible for the energetic protons in the cavities, in which case vertical-bar E vertical-barapprox.50 mV/m. Such a localized source implies radial motions of the magnetospheric plasma with speeds of the order of a few hundred km/s. Such motions could be produced by long-wavelength, small-amplitude Alfven waves in Jupiter's magnetosphere.

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

1980-01-01

178

Magnetic field studies by voyager 2: preliminary results at saturn.  

PubMed

Further studies of the Saturnian magnetosphere and planetary magnetic field by Voyager 2 have substantiated the earlier results derived from Voyager 1 observations in 1980. The magnetic field is primarily that of a centered dipole (moment = 0.21 gauss-RS(3); where one Saturn radius, RS, is 60,330 kilometers) tilted approximately 0.8 degrees from the rotation axis. Near closest approach to Saturn, Voyager 2 traversed a kronographic longitude and latitude range that was complementary to that of Voyager 1. Somewhat surprisingly, no evidence was found in the data or the analysis for any large-scale magnetic anomaly in the northern hemisphere which could be associated with the periodic modulation of Saturnian kilometric radiation radio emissions. Voyager 2 crossed the magnetopause of a relatively compressed Saturnian magnetosphere at 18.5 RS while inbound near the noon meridian. Outbound, near the dawn meridian, the magnetosphere had expanded considerably and the magnetopause boundary was not observed until the spacecraft reached 48.4 to 50.9 RS and possibly beyond. Throughout the outbound magnetosphere passage, a period of 46 hours (4.5 Saturn rotations), the field was relatively steady and smooth showing no evidence for any azimuthal asymmetry or magnetic anomaly in the planetary field. We are thus left with a rather enigmatic situation to understand the basic source of Saturnian kilometric radiation modulation, other than the small dipole tilt. PMID:17771278

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

1982-01-29

179

Infrared observations of the saturnian system from voyager 2.  

PubMed

During the passage of Voyager 2 through the Saturn system, infrared spectral and radiometric data were obtained for Saturn, Titan, Enceladus, Tethys, Iapetus, and the rings. Combined Voyager 1 and Voyager 2 observations of temperatures in the upper troposphere of Saturn indicate a seasonal asymmetry between the northern and southern hemispheres, with superposed small-scale meridional gradients. Comparison of high spatial resolution data from the two hemispheres poleward of 60 degrees latitude suggests an approximate symmetry in the small-scale structure, consistent with the extension of a symmetric system of zonal jets into the polar regions. Longitudinal variations of 1 to 2 K are observed. Disk- averaged infrared spectra of Titan show little change over the 9-month interval between Voyager encounters. By combining Voyager 2 temperature measurements with ground-based geometric albedo determinations, phase integrals of 0.91 +/- 0.13 and 0.89 +/- 0.09 were derived for Tethys and Enceladus, respectively. The subsolar point temperature of dark material on Iapetus must exceed 110 K. Temperatures (and infrared optical depths) for the A and C rings and for the Cassini division are 69 +/- 1 K (0.40 +/- 0.05), 85 +/- 1 K (0.10 +/- 0.03), and 85 +/- 2 K (0.07 +/- 0.04), respectively. PMID:17771275

Hanel, R; Conrath, B; Flasar, F M; Kunde, V; Maguire, W; Pearl, J; Pirraglia, J; Samuelson, R; Cruikshank, D; Gautier, D; Gierasch, P; Horn, L; Ponnamperuma, C

1982-01-29

180

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

181

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

182

A comment on "the far future of exoplanet direct characterization"--the case for interstellar space probes.  

PubMed

Following on from ideas presented in a recent paper by Schneider et al. on "The Far Future of Exoplanet Direct Characterization," I argue that they have exaggerated the technical obstacles to performing such "direct characterization" by means of fast (order 0.1c) interstellar space probes. A brief summary of rapid interstellar spaceflight concepts that may be found in the literature is presented. I argue that the presence of interstellar dust grains, while certainly something that will need to be allowed for in interstellar vehicle design, is unlikely to be the kind of showstopper suggested by Schneider et al. Astrobiology as a discipline would be a major beneficiary of developing an interstellar spaceflight capability, albeit in the longer term, and I argue that astrobiologists should keep an open mind to the possibilities. PMID:21087164

Crawford, Ian A

2010-10-01

183

Voyager in the Vicinity of the Termination Shock  

NASA Astrophysics Data System (ADS)

A new low energy component was observed beginning in mid-2002 when Voyager 1 was at 85 AU, suggesting that the spacecraft was in the vicinity of the termination shock. These termination shock particles (TSPs) are present with increased intensity as Voyager 1 approaches 95 AU, indicating this is a durable feature of this region of the heliosphere and not likely the result of occasional transient events. These observations pose a number of questions concerning the spectral differences of TSPs and anomalous cosmic rays, an apparent average anisotropy direction offset from the average magnetic field, the inferred solar wind velocity and lack of magnetic compression, and a TSP source that is radially inward of Voyager 1. These questions and further observations continue to stimulate new analysis and interpretations. This work was supported by NASA under contract NAS7-03001.

Stone, E. C.

2005-05-01

184

In situ observations of interstellar plasma with Voyager 1.  

PubMed

Launched over 35 years ago, Voyagers 1 and 2 are on an epic journey outward from the Sun to reach the boundary between the solar plasma and the much cooler interstellar medium. The boundary, called the heliopause, is expected to be marked by a large increase in plasma density, from about 0.002 per cubic centimeter (cm(-3)) in the outer heliosphere, to about 0.1 cm(-3) in the interstellar medium. On 9 April 2013, the Voyager 1 plasma wave instrument began detecting locally generated electron plasma oscillations at a frequency of about 2.6 kilohertz. This oscillation frequency corresponds to an electron density of about 0.08 cm(-3), very close to the value expected in the interstellar medium. These and other observations provide strong evidence that Voyager 1 has crossed the heliopause into the nearby interstellar plasma. PMID:24030496

Gurnett, D A; Kurth, W S; Burlaga, L F; Ness, N F

2013-09-12

185

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

186

Plasma observations near saturn: initial results from voyager 2.  

PubMed

Results of measurements of plasma electrons and poitive ions made during the Voyager 2 encounter with Saturn have been combined with measurements from Voyager 1 and Pioneer 11 to define more clearly the configuration of plasma in the Saturnian magnetosphere. The general morphology is well represented by four regions: (i) the shocked solar wind plasma in the magnetosheath, observed between about 30 and 22 Saturn radii (RS) near the noon meridian; (ii) a variable density region between approximately 17 RS and the magnetopause; (iii) an extended thick plasma sheet between approximately 17 and approximately 7 RS symmetrical with respect to Saturn's equatorial plane and rotation axis; and (iv) an inner plasma torus that probably originates from local sources and extends inward from L approximately 7 to less than L approximately 2.7 (L is the magnetic shell parameter). In general, the heavy ions, probably O(+), are more closely confined to the equatorial plane than H(+), so that the ratio of heavy to light ions varies along the trajectory according to the distance of the spacecraft from the equatorial plane. The general configuration of the plasma sheet at Saturn found by Voyager 1 is confirmed, with some notable differences and additions. The "extended plasma sheet," observed between L approximately 7 and L approximately 15 by Voyager 1 is considerably thicker as observed by Voyager 2. Inward of L approximately 4, the plasma sheet collapses to a thin region about the equatorial plane. At the ring plane crossing, L approximately 2.7, the observations are consistent with a density of O(+) of approximately 100 per cubic centimeter, with a temperature of approximately 10 electron volts. The location of the bow shock and magnetopause crossings were consistent with those previously observed. The entire magnetosphere was larger during the outbound passage of Voyager 2 than had been previously observed; however, a magnetosphere of this size or larger is expected approximately 3 percent of the time. PMID:17771279

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; Sittler, E C; Eviatar, A; Siscoe, G L; Goertz, C K; Vasyliunas, V M

1982-01-29

187

The atmospheric structure of Titan from Voyager to Cassini  

NASA Astrophysics Data System (ADS)

Titan's stratosphere has been studied in the past from the Earth and also from space with Voyager, ISO (Coustenis et al., 1998; 2003) and more recently Cassini observations. In particular, spectra recorded by the Composite Infrared Spectrometer (CIRS) aboard the Cassini spacecraft became available during the Titan flybys spanning two years now since SOI (Flasar et al., 2005; Teanby et al., 2006, Vinatier et al., 2006; Nixon et al., 2006; Coustenis et al., 2007). The spectra characterize various regions on Titan from 85°S to 80°N with a variety of emission angles. We have studied the emission observed in the CIRS detector arrays (covering the 10-1500 cm-1 spectral range with apodized resolutions of 2.54 or 0.53 cm-1). We have used temperature profiles retrieved from the inversion of the emission observed in the methane _4 band at 1304 cm-1 and a line-by-line radiative transfer code to infer the abundances of the trace constituents and some of their isotopes in Titan's stratosphere (Coustenis et al., 2007). The composite spectra show several signatures of previously identified molecules: hydrocarbons, nitriles, H2O and CO2. Besides these well-known trace species, a firm detection of benzene (C6H6) is provided by CIRS at 674 cm-1 and allows for the study of its latitudinal variations. No longitudinal variations were found for any of the gases. Information is retrieved on the meridional variations of the trace constituents and tied to predictions by dynamical-photochemical models (Hourdin et al., 2004; Lavvas et al., 2007). Molecules showing a significant enhancement at northern latitudes are the nitriles (HC3N, HCN) and the complex hydrocarbons (C4H2, C3H4). The D/H ratio on Titan was also determined from the CH3D band at 8.6 micron and found to be about 1.2 ą 0.2 10-4. We have also identified the presence of C2HD at 678 cm-1 (Coustenis et al., 2006). Constraints are also set on the vertical distribution of C2H2. We will describe the most relevant results from ground or space regarding Titan's atmospheric structure. References : Coustenis et al., 1998, A&A 336, L85; Coustenis et al., 2003, Icarus 161, 383; Coustenis et al., 2006, BAAS 38; Coustenis et al., 2007, Icarus, in press; Flasar et al., 2005, Science 308, 975 ; Hourdin et al., 2004, J. Geophys. Res. 109, E1205; Nixon et al., 2006, BAAS 38; Lavvas et al., 2007, Plan. Space Sci., submitted; Teanby et al., 2006, Icarus 181, 243; Vinatier et al., 2006, Icarus, in press.

Coustenis, A.

2007-05-01

188

Io's sodium emission cloud and the Voyager 1 encounter  

SciTech Connect

Monitoring of Io's neutral sodium emission cloud, monitored from two earth observatories during the period of the Voyager 1 encounter, demonstrated that the behavior of the cloud is complex displaying a variety of changes, both systematic and secular, which can have both time and spatial dependencies while also possessing some characteristics of stability. Dynamic models of the sodium cloud employing Voyager 1 plasma data provide a reasonable fit to the encounter images of one of the observatories. The modeling assumptions of anisotropic ejection of neutral sodium atoms from the leading, inner hemisphere of Io, with a velocity distribution characteristic of sputtering, adequately explain the overall intensity distribution of the 'near cloud'.

Goldberg, B.A.; Mekler, Y.; Carlson, R.W.; Johnson, T.V.; Matson, D.L.

1980-01-01

189

Analysis of Voyager-1 Observed High-Energy Particle Flux Using MHD Simulation of the Outer Heliosphere  

NASA Astrophysics Data System (ADS)

In situ observations of the outer heliosphere by the Voyager 1 (V1) and Voyager 2 (V2) spacecrafts show highly variable behavior of the solar wind plasma in deep interplanetary space and the heliosheath (HS). We develop a dynamic and realistic model that satisfies both V1 and V2 observed crossing times and locations of the termination shock (TS) simultaneously, by performing a three-dimensional (3D) MHD simulation that includes the effects of neutral particles (Washimi et al. (2010)). Daily values of solar-wind speed and density observed by V2 were used so that short-term dynamical effects are reproduced in this simulation. Here, we compare the V1 observed high-energy charged particle flux data in the HS (Webber et al. (2009)) with our MHD simulation results to identify the flux increase/decrease associated with the March 2006 interplanetary shock events.

Washimi, Haruichi; Zank, Gary P.; Hu, Qiang; Webb, G. M.; Shinagawa, Hiroyuki

2011-09-01

190

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

191

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

192

Voyager 2 plasma ion observations in the magnetosphere of Uranus  

Microsoft Academic Search

Positive ion measurements in the magnetosphere of Uranus have been made by the Voyager 2 plasma science experiment. The paper presents an overview of the entire data set and a detailed analysis of the observations from the inner magnetosphere which complements and extends results reported elsewhere. Densities and temperatures are obtained from an analysis which incorporates details of the instrumental

Richard S. Selesnick; Ralph L. McNutt Jr.

1987-01-01

193

Post Voyager comparisons of the interiors of Uranus and Neptune  

Microsoft Academic Search

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

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

1990-01-01

194

POST Voyager comparisons of the interiors of Uranus and Neptune  

Microsoft Academic Search

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

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

1990-01-01

195

Introducing Students to Darwin via the Voyage of HMS "Beagle"  

ERIC Educational Resources Information Center

|I use the diary that Darwin wrote during the voyage of HMS Beagle and recent images of a few of the places he visited to illustrate some comparisons between Darwin's world and ours. For today's students, increasingly committed to environmental issues, this may be an especially promising way to introduce Darwin.|

Swab, Janice C.

2010-01-01

196

The Voyager 2 Encounter with the Uranian System.  

ERIC Educational Resources Information Center

|A series of 12 reports on the Voyager Two experiments in the Uranian system. Reports are included on: (1) imaging science; (2) photometry; (3) infrared; (4) ultraviolet; (5) radio science; (6) magnetic fields; (7) plasma; (8) charged particles; (9) magnetosphere (hot plasma and radiation); (10) radion observations; and (11) plasma waves. An…

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

1986-01-01

197

A Curriculum Review: The Voyage of the Mimi.  

ERIC Educational Resources Information Center

|The curriculum package, "The Voyage of the Mimi," uses computer, videocassette, student text, and workbook for integrated study of the great whales and the impact of social actions on society and the environment. This review suggests that the package also offers many ancillary teaching opportunities. (CB)|

Johns, Kenneth W.

1988-01-01

198

Too Many Notes: Computers, Complexity and Culture in Voyager  

Microsoft Academic Search

The author discusses his computer music composition, Voyager, which employs a computer-driven, interactive & virtual improvising orchestra that analyzes an improvisor's performance in real time, generating both complex responses to the musician's playing and independent behavior arising from the program's own internal processes. The author contends that notions about the nature and function of music are embedded in the structure

George E. Lewis

2000-01-01

199

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

200

Empirical model of the Io plasma torus: Voyager measurements  

Microsoft Academic Search

We present a description of plasma conditions in the Io plasma torus, between 5 and 10 RJ, based on Voyager 1 observations obtained in March 1979. The model includes updated analyses of Plasma Science (PLS) data obtained along the spacecraft trajectory as well as Ultraviolet Spectrometer (UVS) observations of composition made remotely from Jupiter. The plasma characteristics observed along the

Fran Bagenal

1994-01-01

201

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

202

The Ocean Voyager II: an AUV designed for coastal oceanography  

Microsoft Academic Search

The Ocean Voyager II is a small long-range AUV designed for coastal oceanography. A system overview and design constraints are given with reference to the specific mission of bottom classification through light reflectance and absorption measurement. This mission requires the AUV to fly above the sea floor at a constant altitude while measuring the albedo of the bottom and the

Samuel M. Smith; Stanley E. Dunn

1994-01-01

203

A Curriculum Review: The Voyage of the Mimi.  

ERIC Educational Resources Information Center

The curriculum package, "The Voyage of the Mimi," uses computer, videocassette, student text, and workbook for integrated study of the great whales and the impact of social actions on society and the environment. This review suggests that the package also offers many ancillary teaching opportunities. (CB)

Johns, Kenneth W.

1988-01-01

204

The Polar Sea Voyage and the Northwest Passage Dispute  

Microsoft Academic Search

This study examines the Northwest Passage controversy between the United States and Canada beginning with the U.S. Coast Guard icebreaker Polar Sea voyage through the passage without permission from the Canadian Government in August 1985 to the signing of the executive agreement on Arctic cooperation in January 1988. Particular focus is placed upon U.S. national interests in the Arctic region,

Philip J. Briggs

1990-01-01

205

From Convicts to Colonists: the Health of Prisoners and the Voyage to Australia, 1823 - 1853  

PubMed Central

From 1815, naval surgeons accompanied all convict voyages from Britain and Ireland to the Australian colonies. As their authority grew, naval surgeons on convict ships increasingly used their medical observations about the health of convicts to make pointed and sustained criticisms of British penal reforms. Beyond their authority at sea, surgeons’ journals and correspondence brought debates about penal reform in Britain into direct conversation with debates about colonial transportation. In the 1830s, naval surgeons’ claims brought them into direct conflict with their medical colleagues on land, as well as with the colonial governor, George Arthur. As the surgeons continued their attempts to combat scurvy, their rhetoric changed. By the late 1840s, as convicts’ bodies betrayed the disturbing effects of separate confinement as they boarded the convict ships, surgeons could argue convincingly that the voyage itself was a space that could medically, physically, and spiritually reform convicts. By the mid 1840s, surgeons took the role of key arbiters of convicts’ potential contribution to the Australian colonies.

Foxhall, Katherine

2012-01-01

206

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

NASA Astrophysics Data System (ADS)

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.

1995-05-01

207

In-situ exploration of planetary upper atmospheres with balloons ejected from sounding rockets and space probes  

NASA Astrophysics Data System (ADS)

Balloon missions have been used extensively on Earth to study a large variety of atmospheric characteristics and phenomena. Of primary interest are in situ temperature, pressure and density profiles and wind velocities. The first planetary balloons were flown in the mid 1980s with the Vega 1 and 2 missions to Venus. Since then, balloons have been further developed and planed for, e.g., Mars and Titan. Testing those technologies first on Earth made sense because Earths upper (neutral) atmosphere provides many similarities to Mars atmosphere. The aim of this presentation is to provide a brief overview of the current state in scientific ballooning, and in particular report on the expertise obtained through the MIRIAM (Main Inflated Re-entry Into the Atmosphere Mission Test) Mars balloon near space deployment experiments. The test ballute MIRIAM was flown on board a REXUS 4 sounding rocket from ESRANGE in northern Sweden on October 22nd, 2008. The balloon was deployed at about 140 km altitude. On board were optical instruments, magnetometers, temperature sensors and barometers for atmospheric studies. The data gathered during decent was used to validate inflation, deployment concepts and planetary balloon technologies. Based on those results a new ballute probe MIRIAM-2 is under construction. Its aim is the recording atmospheric parameters which will be then compared to Earth upper atmospheric models. Finally, we address and discuss future prospects for balloon in situ exploration of Mars atmosphere.

Danielides, Michael; Griebel, Hannes; Bayler, Klaus; Herholz, J.

208

Encapsulated guest-host dynamics: guest rotational barriers and tumbling as a probe of host interior cavity space.  

PubMed

The supramolecular host assembly [Ga(4)L(6)](12-) (1; L = 1,5-bis[2,3-dihydroxybenzamido]naphthalene) encapsulates cationic guest molecules within its hydrophobic cavity and catalyzes a variety of chemical transformations within its confined interior space. Despite the well-defined structure, the host ligand framework and interior cavity are very flexible and 1 can accommodate a wide range of guest shapes and sizes. These observations raise questions about the steric effects of confinement within 1 and how encapsulation fundamentally changes the motions of guest molecules. Here we examine the motional dynamics (guest bond rotation and tumbling) of encapsulated guest molecules to probe the steric consequences of encapsulation within host 1. Encapsulation is found to increase the Ph-CH(2) bond rotational barrier for ortho-substituted benzyl phosphonium guest molecules by 3 to 6 kcal/mol, and the barrier is found to depend on both guest size and shape. The tumbling dynamics of guests encapsulated in 1 were also investigated, and here it was found that longer, more prolate-shaped guest molecules tumble more slowly in the host cavity than larger but more spherical guest molecules. The prolate guests reduce the host symmetry from T to C(1) in solution at low temperatures, and the distortion of the host framework that is in part responsible for this symmetry reduction is observed directly in the solid state. Analysis of guest motional dynamics is a powerful method for interrogating host structure and fundamental host-guest interactions. PMID:20977233

Mugridge, Jeffrey S; Szigethy, Géza; Bergman, Robert G; Raymond, Kenneth N

2010-10-26

209

The galilean satellites and jupiter: voyager 2 imaging science results.  

PubMed

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. PMID:17733910

Smith, B A; Soderblom, L A; Beebe, R; Boyce, J; Briggs, G; Carr, M; Collins, S A; Cook, A F; 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

1979-11-23

210

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.

211

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

212

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

213

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

214

Message passing support on StarT-Voyager  

Microsoft Academic Search

No single message passing mechanism can efficiently support all types of communication that commonly occur in most parallel or distributed programs. MIT's StarT-Voyager, a hybrid message passing\\/shared memory parallel machine, provides four message passing mechanisms to achieve high performance over a wide spectrum of communication types and sizes. Hardware and address translation enforced protection allows direct user-level access to message

Boon S. Ang; Derek Chiou; Larry Rudolph; Arvind

1998-01-01

215

Titan's Thermal Emission Spectrum: Reanalysis of the Voyager Infrared Measurements  

Microsoft Academic Search

We have modeled the far-infrared spectrum of Titan between 200 and 600 cm-1, including the fine structure of the H2-N2 and H2-CH4 dimers around 355 and 585 cm-1 respectively. A selection of 373 Voyager IRIS spectra recorded at low and mid-latitudes provides the observational basis for our analysis. The opacity model is significantly improved over previous work by taking into

Régis Courtin; Daniel Gautier; Christopher P. McKay

1995-01-01

216

Titan's atmospheric composition: from Voyager to Cassini and beyond  

Microsoft Academic Search

Titan's atmosphere was revealed by the Voyager missions in the 80s. The trace composition was in particular inferred from infrared spectra by the V1\\/IRIS Spectrometer. ISO gave us an opportunity to further explore this exciting milieu in 1997 (Coustenis et al., 1998; 2003) and brought the discovery of new molecules : H2O and C6H6. Our understanding of Titan's atmospheric chemical

A. Coustenis

2007-01-01

217

Voyager observations of termination shock particles in the heliosheath  

NASA Astrophysics Data System (ADS)

Both Voyager spacecraft have now crossed the termination shock (TS) of the solar wind and are in the heliosheath. Below ˜10 MeV/nuc for H and He, the energy spectra are dominated by termination shock particles (TSPs) that are convected to the spacecraft from nearby regions of the TS where they were recently accelerated. At higher energies, anomalous cosmic rays, which appear to have a source remote from the local region of the TS, and galactic cosmic rays dominate. Soon after Voyager 2 (V2) crossed the termination shock in the southern hemisphere in late August 2007, the TSP spectrum of H had a harder spectrum up to ˜3 MeV than did the concurrent spectrum of TSPs at Voyager 1 (V1) in the north. At 5 MeV, the intensity at V2 was ˜ 4 times that concurrently observed at V1. Since the V2 shock crossing, the V2 TSP spectra in the heliosheath have evolved significantly, and by February 2008 the H intensity at 5 MeV has declined to a level similar to that at V1. We will present the latest observations of the energy spectra of TSP H and He at V1 and V2 and discuss the implications for their acceleration mechanism. This work was supported by NASA under contract NAS7-03001.

Stone, Edward; Stone, Edward; Cummings, A. C.; McDonald, F. B.; Heikkila, B. C.; Lal, N.; Webber, Bill

218

Infrared observations of the jovian system from voyager 2.  

PubMed

Infrared spectra obtainedfrom Voyager 2 have provided additional data on the Jovian system, complementing those obtained from Voyager 1. The abundance ratio of ethane to acetylene in Jupiter's atmosphere appears to be about three times larger in the polar regions than at lower latitudes. A decidedly hemispherical asymmetry exists, with somewhat higher ratios prevailing in northern latitudes. An overall increase in the abundance ratio by a factor of about 1.7 appears to have occurred between the Voyager 1 and 2 encounters. Global brightness temperature maps of Jupiter at 226 and 602 cm(-1) exhibit a large amount of local- and planetary-scale structure, as well as temporal variability. Although heterogeneous cloud structure and ammonia concentration in the lower troposphere may contribute to the appearance of the 226-cm(-1) map, the detail in the 602-cm(-1) maps probably represents the actual horizontal thermal structure near the tropopause and suggests that dynamical heating and cooling processes are important. Low-latitude surface temperatures on the Galilean satellites rangefrom approximately 80 K on the dark sides to 155 K at the subsolar point on Callisto. Below a thin insulating layer, the thermal inertia of Callisto is somewhat greater than that of Earth's moon. Upper limits on the infrared optical depth of the Jovian ring rangingfrom approximately 3 x 10(-4) at 250 cm(-1) to 3 x 10(-3) at 600 cm(-1) have been found. PMID:17733912

Hanel, R; Conrath, B; Flasar, M; Herath, L; Kunde, V; Lowman, P; Maguire, W; Pearl, J; Pirraglia, J; Samuelson, R; Gautier, D; Gierasch, P; Horn, L; Kumar, S; Ponnamperuma, C

1979-11-23

219

A Novel probe for in-situ Electron density and Neutral Wind (ENWi) measurements in the near Earth space  

Microsoft Academic Search

A novel method for the in-situ measurement of thermospheric and ionospheric parameters has successfully been tried out by means of a new probe ENWi. The probe has been designed for neutral wind and electron density measurements up to ?115km. ENWi was successfully flight tested on sounding rockets from Thumba, India during the recent annular solar eclipse (January 2010) that passed

G. Manju; R. Sridharan; P. Sreelatha; Sudha Ravindran; M. K. Madhav Haridas; Tarun K. Pant; P. Pradeep Kumar; R. Satheesh Thampi; Neha Naik; N. Mridula; Lijo Jose; S. G. Sumod

220

Jules Verne Voyager: A Web Interactive Tool for Comparative Planetology  

NASA Astrophysics Data System (ADS)

A Web interactive map tool called "Jules Verne Voyager" was originally developed in 1999 by UNAVCO and continues to evolve. The Voyager tool can easily be used for comparative planetology studies by grades 8-14. Thematic mapping datasets, now totaling about 70 Gb, can be accessed by the tool and include global-scale maps of the inner solar system planets and moons, plus Jupiter and the Galilean moons. The map images are viewed on a Web browser created on demand by the server system. On the client-side, only a Java-enabled browser is required, and the Voyager Java applet runs well with common browsers like Netscape, Mozilla, Opera, and Internet Explorer. The applet sends a key-value pair URL to the http://jules.unavco.org server which queues incoming requests and sends them to a bank of computers dedicated to map image creation. The engine for map image creation makes use of the "Generic Mapping Tools" (GMT) software of Paul Wessel and Walter Smith, followed by image conversion of the GMT-created PostScript to GIF for raster image export and display back on the client browser. Because of the GMT-based engine on the server system, the student user can easily create the same type of images from real planetary data that researchers create. The tool also gives a student the ability to switch background datasets and overlay certain other thematic datasets, thus providing a minimal GIS capability. To our knowledge, the map tool has not yet formally been used in a 8-14 classroom environment, though informal use by students and teachers in these grades suggest that it would be well received. The server system is currently capable of handing a moderate level of requests that would result from classroom use; for example, as a system benchmark, over 800 Voyager images were created and served in about an hour during a DLESE 2003 annual meeting workshop. The Voyager map tool is being used by instructors in earth science and comparative planetology as a means to create customized images for classroom use, minimizing the need for Web searches to find equivalent material. We also welcome collaboration which would augment our current planetary thematic mapping datasets.

Estey, L.; Pappalardo, R.; Meertens, C.

2004-12-01

221

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-Nogučs, Pierre

2011-01-01

222

Titan's atmospheric composition: from Voyager to Cassini and beyond  

NASA Astrophysics Data System (ADS)

Titan's atmosphere was revealed by the Voyager missions in the 80s. The trace composition was in particular inferred from infrared spectra by the V1/IRIS Spectrometer. ISO gave us an opportunity to further explore this exciting milieu in 1997 (Coustenis et al., 1998; 2003) and brought the discovery of new molecules : H2O and C6H6. Our understanding of Titan's atmospheric chemical composition has recently been enhanced by the data returned by the Cassini instruments. Spectra recorded by the Composite Infrared Spectrometer (CIRS) aboard the Cassini spacecraft have been processed from the Titan flybys spanning three years now since SOI (Flasar et al., 2005; Teanby et al., 2006, Vinatier et al., 2006; Nixon et al., 2006; Coustenis et al., 2007). The spectra characterize various regions on Titan from 85°S to 80°N with a variety of emission angles. We have studied the emission observed in the CIRS detector arrays (covering the 10-1500 cm-1 spectral range with apodized resolutions of 2.54 or 0.53 cm-1). We have used temperature profiles retrieved from the inversion of the emission observed in the methane band at 1304 cm-1 and a line-by-line radiative transfer code to infer the abundances of the trace constituents and some of their isotopes in Titan's stratosphere (Coustenis et al., 2007a). The composite spectra show several signatures of previously identified molecules: hydrocarbons, nitriles, H2O and CO2. Besides these well-known trace species, a firm detection of benzene (C6H6) is provided by CIRS at 674 cm-1 and allows for the study of its latitudinal variations. No longitudinal variations were found for any of the gases. Information is retrieved on the meridional variations of the trace constituents and tied to predictions by dynamical-photochemical models (Hourdin et al., 2004; Lavvas et al., 2007). Molecules showing a significant enhancement at northern latitudes are the nitriles (HC3N, HCN) and the complex hydrocarbons (C4H2, C3H4). The D/H ratio on Titan was also determined from the CH3D band at 8.6 micron and found to be about 1.2 ą 0.2 × 10-4. We have also identified the presence of C2HD at 678 cm-1 for the first time (Coustenis et al., 2007b, in preparation). Constraints are also set on the vertical distribution of C2H2. However successful, the Cassini-Huygens mission has brought new enquiries that can only be answered by future missions to Titan. Such a mission, a collaboration between ESA and NASA in the spirit of Cassini, was recently proposed by the TANDEM Consortium in response to ESA's Cosmic Vision Call. References : Coustenis et al., 1989, Icarus 80, 54; Coustenis et al., 1998, A & A 336, L85-L89; Coustenis et al., 2003, Icarus 161, 383; Coustenis et al., 2007a, Icarus 1889, 35-62; Flasar et al., 2005, Science 308, 975 ; Hourdin et al., 2004, J. Geophys. Res. 109, E1205; Nixon et al., 2007, Icarus, in press; Lavvas et al., 2007, Plan. Space Sci., in press; Teanby et al., 2006, Icarus 181, 243; Vinatier et al., 2006, Icarus, 188, 120.

Coustenis, A.

2007-12-01

223

Analysis of Voyager images of Europa - plasma bombardment  

SciTech Connect

Voyager-derived data on the albedos of Europa are presently photometrically corrected and converted into average, single-scattering form, in order to analyze them as a function of angular distance from the apex of orbital motion. A hypothesized magnetospheric modification of the Europa surface is confirmed by the UV absorption found in the 0.35-micron filter data; this absorption directly correlates with the longitudinal ion implantation distribution in both terrain types. A red spectrum is found in both terrain types as well, and is found to be constant across the surface. A uniform increase is noted in the dark terrain absorption over that in the bright terrain. 43 references.

Johnson, R.E.; Nelson, M.L.; Nccord, T.B.; Gradie, J.C.

1988-09-01

224

Jupiter plasma wave observations: an initial voyager 1 overview.  

PubMed

The Voyager I 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 turbulence, and discrete whistlers, apparently associated with lightning. Some strong emissions in the tail region and some impulsive signals have not yet been positively identified. PMID:17800437

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

1979-06-01

225

THE LOCAL INTERSTELLAR SPECTRUM BEYOND THE HELIOPAUSE: WHAT CAN BE LEARNED FROM VOYAGER IN THE INNER HELIOSHEATH?  

SciTech Connect

The local interstellar spectrum (LIS) is one of the most important but unknown parameters used in all modeling efforts to describe the modulation of Galactic cosmic rays on their way from the galaxy through a possible bow shock, heliosheath, and heliosphere toward the Earth. Because it has not been measured thus far, several LIS models derived from numerical simulations or data on Earth were developed. A new method to determine the LIS was introduced when the Voyager spacecraft crossed the termination shock and entered the heliosheath. Webber and Higbie derived a new LIS, which is lower than all previous LIS models over the entire energy range, on the basis of these measurements. Numerical simulations by Scherer et al. showed that particles already in the outer heliosheath (OHS) are modulated, suggesting that the LIS by Webber and Higbie is a heliopause spectrum (HPS) rather than the ''true'' LIS. By using the same simplified simulation model, we estimate the diffusion coefficient in the OHS to be consistent with several 10{sup 26} to 10{sup 27} cm{sup 2} s{sup -1} for all LIS models under consideration by mapping them to this HPS and conclude that the Voyager measurements will not be able to determine the LIS in the near future. We then discuss the circumstances under which the terrestrial archive can be used to at least exclude LIS models, unless one awaits a dedicated mission like e.g., the Interstellar Probe.

Herbst, K.; Heber, B.; Kopp, A.; Sternal, O. [IEAP, Christian-Albrechts-Universitaet zu Kiel, Leibnizstrasse 11, D-24118 Kiel (Germany); Steinhilber, F., E-mail: herbst@physik.uni-kiel.de [Swiss Federal Institute of Aquatic Science and Technology, Eawag, CH-8600 Duebendorf (Switzerland)

2012-12-10

226

Discovery by Voyager-2 of Predicted Satellites Which Determine Resonance Nature of Uranian Rings (Abstract Only).  

National Technical Information Service (NTIS)

Voyager 2 data have fully confirmed the hypothesis that Uranus rings are resonant in nature and that their locations are determined by the 1:2, 2:3, and 3:4 resonances from unknown satellites. Voyager 2 discovered a number of small satellites beyond the e...

N. N. Gorkavyy A. M. Fridman

1987-01-01

227

Uranus after Voyager 2 and the origin of the solar system  

Microsoft Academic Search

The discoveries made by the Voyager 2 spacecraft at Uranus in January 1986 are discussed in the light of the modern Laplacian theory for the formation of the solar system. The most important confirmation by Voyager was the discovery of 2 new satellite groups near orbital radii 2 1\\/2 RU and 3 1\\/2 RU (RU = Uranus' equatorial radius), as

A. J. R. Prentice

1986-01-01

228

33 CFR 157.162 - Crude oil washing during a voyage.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Crude oil washing during a voyage. 157...TO TANK VESSELS CARRYING OIL IN BULK Crude Oil Washing (COW) System on Tank Vessels Cow Operations § 157.162 Crude oil washing during a voyage....

2013-07-01

229

The Columbian Voyages, the Columbian Exchange, and Their Historians. Essays on Global and Comparative History.  

ERIC Educational Resources Information Center

The 500th anniversary of the Columbian discovery of America is upon us, and with it the obligation to assess existing interpretations of the significance of the voyage and establishment of permanent links between the Old and New Worlds. The traditional, or bardic, version of the Columbian voyages and their consequences was the product of narrative…

Crosby, Alfred W.

230

Pioneer and voyager observations of the solar wind at large heliocentric distances and lattitudes  

Microsoft Academic Search

The Pioneer 10, 11, and Voyager 2 spacecraft are well suited for exploring spatial gradients in the distant solar wind. Between 1984 and 1986 Pioneer 11 and Voyager 2 were located at nearly the same heliocentric distance (approx. =20 AU) and longitude but were widely separated in latitude; Pioneer 11 was at a heliographic latitude of greater than or equal

P. R. Gazis; J. D. Mihalov; A. Barnes; A. J. Lazarus; E. J. Smith

1989-01-01

231

33 CFR 157.228 - Isolating Valves: Closed during a voyage.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Isolating Valves: Closed during a voyage. 157.228...Tanks Operations § 157.228 Isolating Valves: Closed during a voyage. (a) The...10c(c)(2) shall ensure that the valves under § 157.222(d) remain...

2013-07-01

232

Celebrating one year of atmospheric evolution on Titan since Voyager with Cassini/CIRS  

NASA Astrophysics Data System (ADS)

Seven years after Cassini's Saturn orbit insertion, we have in hand almost a complete picture of the stratospheric evolution within a Titanian year by combining Voyager 1 Infrared Radiometer Spectrometer (IRIS) measurements from 1980, Cassini Composite Infrared Spectrometer (CIRS) continuous recordings from 2004 to 2010 and the intervening ground-based and space-borne observations with ISO (Coustenis et al. 2003). We have re-analyzed the Voyager 1/IRIS data acquired during the 1980 encounter, 30 years (one Titan revolution) before 2010, with the most recent spectroscopic data releases and haze descriptions (Vinatier et al. 2010, 2012) by using our radiative transfer code (ART). The re-analysis confirms the V1/IRIS retrievals by Coustenis & Bezard (1995) and updates the abundances for all molecules and latitudes based on new temperature, haze and spectroscopic parameters. ART was also applied to all available CIRS spectral averages corresponding to more than 70 flybys binned over 10° in latitude for both medium (2.5 cm-1) and higher (0.5 cm-1) resolutions and from nadir and limb data both. In these spectra, we search for variations in temperature (following the method in Achterberg et al. 2011) and composition at northern (around 50°N), equatorial and southern (around 50°S) latitudes as the season on Titan progresses and compare them to the new V1/IRIS, ISO and other ground-based reported composition values (Coustenis et al., 2012, in prep). Other latitudes were examined in previous papers (e.g. Coustenis et al. 2010). With this study we search for interannual stratospheric thermal and chemical variations at a time when the season is exactly the same as the one of the Voyager flyby and until it moves towards northern summer solstice which will be observed by the Cassini extended Solstice mission. We find significant temperature variations, essentially a decrease with time during the Cassini mission. Little departure from the original V1/IRIS abundances at the lower latitudes, but some variations in the northern latitudes, with C2H2, HCN and CO2 presently above and the complex hydrocarbons C3H4 and C4H2 below the initial values. This allows us to set constraints on seasonal, photochemical and circulation models of Titan. References: Achterberg R., et al.: " Temporal variations of Titan’s middle-atmospheric temperatures from 2004 to 2009 observed by Cassini/CIRS". Icarus, Vol. 211, pp. 686-698, 2011. Coustenis, A., Bezard, B.: "Titan’s atmosphere from Voyager infrared observations. IV. Latitudinal variations of temperature and composition". Icarus, Vol. 115, pp. 126-140, 1995. Coustenis, A., et al.: "Titan’s atmosphere from ISO mid-infrared spectroscopy". Icarus, Vol. 161, pp. 383-403, 2003. Coustenis, A., et al.: " Titan trace gaseous composition from CIRS at the end of the Cassini-Huygens prime mission". Icarus, Vol. 207, pp. 461-476, 2010. Coustenis, A., et al.: "One Titanian Year : Temporal Variations in Stratospheric Temperature and Chemical Composition". Submitted (2012). Vinatier, S., et al. : “Analysis of Cassini/CIRS limb spectra of Titan acquired during the nominal mission II: Aerosol extinction profiles in the 600-1420 cm-1 spectral range”. Icarus 210, 852-866 (2010). Vinatier, S., et al. : “Optical constants of Titan’s stratospheric aerosols in the 70-1500 cm-1 spectral range constrained from Cassini/CIRS observations”. Icarus submitted (2012).

Coustenis, A.; Bampasidis, G.; Vinatier, S.; Achterberg, R.; Lavvas, P.; Nixon, C.; Jennings, D.; Teanby, N.; Flasar, F. M.; Carlson, R.; Orton, G.; Romani, P.; Guandique, E. A.

2012-04-01

233

Encounter with saturn: voyager 1 imaging science results.  

PubMed

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. PMID:17783827

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; Cuzzi, J; Pollack, J B; Danielson, G E; 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

1981-04-10

234

Changes in Uranus' Atmosphere Since the Voyager Encounter  

NASA Astrophysics Data System (ADS)

We propose to combine all the available WFPC2 and NICMOS images of Uranus to investigate the causes of Uranus' long- term temporal variability, including several discrete clouds which apparently have lifetimes of several months. The PI has already developed atmospheric scattering models to fit the Voyager observations of Uranus' southern hemisphere {Rages Etal 1991, Rages and Pollack 1994}, and is now modifying them to reproduce the Cycle 6 WFPC2 observations of Hammel et al. We propose to enhance the vertical resolution of the Cycle 6 models by inclusion of the Cycle 7 data of Tomasko et al., and to model observations from previous cycles to investigate the timing of possible changes in {1} the methane cloud's altitude, optical thickness, and single scattering albedo; {2} aerosol absorption below the base of the methane cloud; and {3} height of the putative H_2S cloud at 3 bars. We will examine northern latitudes up to 30degrees N to check for possible hemispheric asymmetries in the atmospheric structure. We will also study how the structure of the discrete clouds differs from that of the surrounding atmosphere. The work proposed here complements our previous Cycle 6, approved Cycle 7 and requested Cycle 8 observations of Uranus by {1} extending the wavelength range for modeling of our pre-1998 observations and {2} using data from 1994 and 1995 to partially fill the 10-year gap since the Voyager encounter.

Rages, Kathy

1999-07-01

235

Voyager observations of energetic particles near the termination shock  

NASA Astrophysics Data System (ADS)

We present new observations of spectral characteristics of low-energy particles from Voyager 1 and 2 V1 and V2 based on an improved analysis technique We find that the proton power-law index for 0 5 leq E leq 1 5 MeV as measured by V1 in the heliosheath from days 23 to 359 of 2005 has a median value of -1 7 with a daily rms variation of pm 0 1 There are transient features in the spectra both in the heliosheath and in the upstream region Strong field-aligned streaming is observed in the region just upstream of the shock where it has been suggested that the spectrum corresponds to the suprathermal tail of pickup ions in the solar wind Voyager 2 began observing termination shock particles TSPs streaming inward along the spiral magnetic field from the termination shock at sim 76 AU opposite to the streaming direction at V1 The V2 proton TSP spectra are similar to those observed by V1 with a spectral break near 3 MeV Similar spectral breaks are also observed during transient interplanetary events associated with merged interaction regions This work was supported by NASA under contract NAS7-03001

Cummings, A. C.; Stone, E. C.

236

Comparing Clumps in Saturn's F Ring from Voyager to Cassini  

NASA Astrophysics Data System (ADS)

Saturn’s F ring is unusual in that it is subject to dynamic structural changes over short periods - anywhere from days to months. Images from the Voyager and Cassini spacecraft have revealed phenomena such as kinks, fans, channels, streamers, and clumps, all of which change over these short time intervals. While the causes of some of these features have been explained and well documented, we are still attempting to learn more about others. This work focuses on the nature and behavior of clumps, diffuse bright regions that extend 3-40 degrees in longitude. Previous work by Showalter (2004, Icarus, 171, 356) showed that it was possible to analyze and track clumps with respect to the F ring's mean motion using Voyager data. Now using 6 years’ worth of Cassini images, we have developed a new method of detecting clumps using wavelet theory. We compare the physical attributes of current clumps to those analyzed in the Showalter study and find significant differences. In general, modern clumps are wider, less bright, and occur less frequently. It is becoming increasingly evident that the F ring we see today is not the same ring it was 30 years ago.

Hicks, Shannon; French, R. S.; Showalter, M. R.; Antonsen, A.; Packard, D.

2013-01-01

237

Diffuse UV Background - GALEX Imaging and Voyager Spectroscopy  

NASA Astrophysics Data System (ADS)

We propose a LEGACY project, with the aim of characterizing the diffuse ultraviolet background radiation. In order to achieve maximum impact, we propose to observe exclusively targets for which we already have in hand Voyager diffuse background spectra shortward of Lyman alpha. Our Voyager spectroscopy will allow powerful insight into the interpretation and meaning of the deep GALEX images (longward of Lyman alpha) that we propose (here) to obtain. There is good evidence that a substantial portion of the diffuse UV background at moderate and high Galactic latitudes is exotic in its origin---that is, that the radiation is not simply diffuse galactic light plus the integrated light of distant galaxies. We propose to find clues to the nature and physical origin of the diffuse ultraviolet background radiation in as comprehensive a manner as can be accomplished using GALEX. But in the course of carrying out the proposed work, we will also be creating a permanent GALEX archive of well-chosen deep images that are supported by spectroscopy---images valuable for a wide range of purposes beyond those that we propose. To speed this broader use, we waive all data rights. We successfully proved the feasibility and concept with a few exploratory pointings in Cycle 1, which support our current request for a comprehensive (Legacy) program.

Henry, Richard

238

Recalibration of the Voyager PRA antenna for polarization sense measurement  

NASA Astrophysics Data System (ADS)

The Voyager Planetary Radio Astronomy (PRA) antenna and receiver system provides an indication of the sense of elliptical or circular polarization of radiation that is not correct for all directions of incidence. The true sense could be determined for all directions if accurate calibration data were available. It was not feasible to make the calibration before the Voyagers were launched. Lecacheux & Ortega-Molina (1987), however, were able to derive such calibration data from planetary radio observations made in flight. They expressed their results in terms of the tilt of a plane (the E-plane) that divides the incident ray directions for which the indicated polarization sense is correct from those directions for which the indicated sense is reversed. We demonstrate that there are certain directions for which this calibration is itself in error, and that the surface dividing the two sets of incident rays is more complex than a tilted plane. We are able to make a crude approximation to the true surface from the limited data available.

Wang, L.; Carr, T. D.

1994-01-01

239

46 CFR 2.01-8 - Application of regulations to vessels or tankships on an international voyage.  

Code of Federal Regulations, 2011 CFR

...regulations to vessels or tankships on an international voyage. 2.01-8 Section 2...regulations to vessels or tankships on an international voyage. (a) Where, in various...stipulated specifically for vessels on an international voyage or tankships on an...

2011-10-01

240

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

241

Voyager infrared observations of the outer solar system  

SciTech Connect

During the Voyager 1 and 2 encounters with Jupiter and Neptune, global mapping sequences were obtained by the Infrared Interferometer Spectrometer (IRIS). Previously performed inversions of these spectra allow the maps to be converted to digital images of various atmospheric properties. Fourier transforms of these images indicate significant longitudinally periodic structure. Cross correlations of the Jupiter maps show that the thermal fields are dominated by large slow or stationary features, despite substantial aerosol velocities at those pressure levels. Two mechanisms are proposed as explanations for the above. The first, forcing from the nonrotating deep atmosphere, is explored analytically. For the second, horizontal influence, a numerical model is developed in which resonances within an equatorial channel are initiated by a meridional perturbation velocity at one boundary. Explanations of both theories are given.

Weir, A. L.

1990-01-01

242

Losing it in New Guinea: the voyage of HMS Rattlesnake.  

PubMed

The voyage of the HMS Rattlesnake to New Guinea and the archipelago to the east of it could have achieved so much for science. 'Make sure of what you do', enthused British hydrographer Francis Beaufort to the Rattlesnake's commander Owen Stanley in 1848. 'Do not leave interesting questions to be answered at the next visit - give names to Capes and Islands...and bring yourself and your people back without quarrels'. But for some reason Stanley wavered. There were several scientists on board the Rattlesnake desperate to ask interesting questions of these uncharted islands. But these natural historians, and in particular a young Thomas Henry Huxley, found their ambitions thwarted by their increasingly edgy captain. PMID:15935857

Goodman, Jordan

2005-06-01

243

The Voyager 2 encounter with the Neptunian system  

SciTech Connect

An overview of the Voyager 2 encounter with Neptune is presented, including a brief discussion of the trajectory, the planned observations, and highlights of the results described in the 11 companion papers. Neptune's blue atmosphere has storm systems reminiscent of those in Jupiter's atmosphere. An optically thin methane ice cloud exists near the 1.5-bar pressure level, and an optically thick cloud exists below 3 bars. Neptune's magnetic field is highly tilted and offset from the planet's center; it rotates with a period of 16.11 hours. Two narrow and two broad rings circle the planet; the outermost of these rings has three optically thicker arc segments. Six moons were discovered in circular prograde orbits, all well inside Triton's retrograde orbit. Triton has a highly reflective and geologically young surface, a thin nitrogen atmosphere, and at least two active geyser-like plumes.

Stone, E.C.; Miner, E.D. (California Institute of Technology, Pasadena (USA))

1989-12-15

244

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

245

Atmospheric Variation on Saturn: From Voyager to Cassini  

NASA Astrophysics Data System (ADS)

Here we report the combined spacecraft observations of Saturn acquired over one Saturnian year 29.5 Earth years), from the Voyager encounters (1980-81) to the new Cassini reconnaissance (2009-10). The combined observations reveal a strong temporal increase of tropic temperature 10 K) around the tropopause of Saturn (i.e., 50 mbar), which is one order-of-magnitude stronger than the seasonal variability 1-2 K). We also provide the first estimate of the zonal winds at 750 mbar, which is close to the zonal winds at 2000 mbar. The quasi-consistency of zonal winds between these two levels provides observational support to a numerical suggestion inferring that the zonal winds at pressures greater than 500 mbar do not vary significantly with depth. Furthermore, the temporal variation of zonal winds decreases its magnitude with depth, implying that the relatively deep zonal winds are stable with time.

Li, Liming; Achterberg, R.; Conrath, B.; Gierasch, P.; Smith, M.; Simon-Miller, A.; Nixon, C.; Orton, G.; Flasar, F.; Jiang, X.; Baines, K.; Morales-Juberias, R.; Ingersoll, A.; Vasavada, A.; Del Genio, A.; West, R.; Ewald, S.; CIRS Team; Cassini Team; ISS Team; VIMS Team

2013-10-01

246

The Voyager 1/Saturn encounter and the cosmogonic shadow effect  

NASA Astrophysics Data System (ADS)

The Voyager 1/Saturn mission results show that the macrostructure of the Saturnian ring system can be explained in terms of the following effect at the time of the system's formation: (1) if an electrically conducting medium such as a dusty plasma rotates around a gravitating central body, which possesses an axisymmetric dipole field, the medium will (2) be two-thirds supported by the centrifugal force and (3) one-third supported by electromagnetic forces, under the condition that the magnetic field is strong enough to control the motion. If the magnetic forces disappear, for instance through a de-ionization of the dusty plasma, the medium will (4) fall down to two-thirds of its original central distance. The result of this process will be a 'cosmogonic shadow' effect, which is described in detail. The agreement between theoretical results and observations is better than a few percent.

Alfven, H.

1981-10-01

247

The thermal structure of Triton's atmosphere - Pre-Voyager models  

NASA Astrophysics Data System (ADS)

Spectral data from earth observations have indicated the presence of N2 and CH4 on Triton. This paper outlines the use of the 1-D radiative-convective model developed for Titan to calculate the current pressure of N2 and CH4 on Triton. The production of haze material is obtained by scaling down from the Titan value. Results and predictions for the Voyager Triton encounter are as follows: A N2-CH4 atmosphere on Triton is thermodynamically self consistent and would have a surface pressure of approximately 50 millibar; due to the chemically produced haze, Triton has a hot atmosphere with a temperature of approximately 130 K; Triton's troposphere is a region of saturation of the major constituent of the atmosphere, N2.

McKay, C. P.; Pollack, J. B.; Zent, A. P.; Cruikshank, D. P.; Courtin, R.

1989-08-01

248

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

249

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

NASA Astrophysics Data System (ADS)

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 sq.arcmin of the cameras - somewhat greater that the SAO (Smithsonian Astrophsyical Observatory Staff 1966) and the AGK3 (Dieckvoss et al. 1975) densities - and a positional accuracy +/- 0.5". Visual magnitudes were also required. The completed catalog contains 4551 stars in the right ascension range 12h 40min to 14h 12min, declination zones +02deg. to -09deg. Mean errors of the positions, as derived from least squares solutions against the Perth 70 Catalogue (Hoeg and von der Heide 1976), are about 0.25"; however, individual residuals for some bright and excessively faint stars are as high as 0.5" to 1.0". The accidental error of one measurement, as deduced from a tabular histogram given in the original catalog publication (referenced below), is about 0.09". Apparent photographic and visual magnitudes were derived from iris photometer measurements, visual magnitude being approximated from a derived color-index relation using UBV stars selected from the USNO photoelectric catalog (Blanco et al. 1968) and extended with Perth 70 stars. The resulting magnitudes appear to have mean errors of at least 0.2mag - 0.3mag for the brighter stars (visual magnitude < 10mag) and uncertainties can be as much as 0.5mag for the fainter stars. The magnitudes are considered to be only approximate, especially on the faint end, because of a lack of photoelectric standards there. For additional information concerning the observations and reductions, the original publication (available from A. R. Klemola) should be consulted. (1 data file).

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

1995-05-01

250

Space Stuff  

NSDL National Science Digital Library

Students are introduced to general space science with information about astronauts, space probes, space travel, the Hubble Space Telescope, space suits, and the Columbia Shuttle accident. Biographies of important scientists and astronauts are included, and vocabulary crossword puzzles, maps, logic riddles, and coloring pages extend learning. Each page offers links to a glossary of important terms. A link to content for more advanced students is included.

251

Great SEP events and space weather, 5. Expected radiation hazard for space probes in space at different distances from the Sun, for satellites in the Earth's magnetosphere at different orbits, for airplanes at different air-lines, and on the ground in dependence of altitude and cutoff rigidity  

NASA Astrophysics Data System (ADS)

In report Applbaum et al. (2010) was described how works automatically the program allowed by using one minute data of NM and satellite data for different moments of time to determine time of ejection, diffusion coefficient in the interplanetary space and energy spectrum in source of SEP . These results were obtained for extended interval of solar CR energy, to which are sensitive NM and satellites. Then obtained results we use in equation, described SEP propagation in space, and by using method of coupling functions determine the expected radiation hazard for space probes in space at different distances from the Sun, for satellites in the Earth's magnetosphere at different orbits, for airplanes at different air-lines, and on the ground in dependence of altitude and cutoff rigidity. REFERENCES: Applbaum et al., "Great SEP events and space weather, 4. Simultaneously using of NM and satellite one minute data", Report on COSPAR 2010, Event PSW-1.

Dorman, Lev; Applbaum, David; Pustil'Nik, Lev; Sternlieb, Abraham; Zagnetko, Alexander; Zukerman, Igor

252

Small sensor probe for monitoring the space electromagnetic environments by the application of the miniaturized plasma wave receiver  

NASA Astrophysics Data System (ADS)

Plasma waves act as the medium in the transport of kinetic energies through wave-particle interactions in space plasmas. Therefore, most of the space missions to investigate space plasmas carry the onboard plasma wave receivers, which is a kind of radio receivers with very high sensitivities. Recently, the downsized satellites in science missions such as formation flights and small satellites require the further reduction of power and mass budget for onboard instruments. We also face the similar requirement from the lack of the spacecraft resources in planetary missions. To meet the requirement, we developed the very small plasma wave receiver using the analogue ASIC (Application Specific Integrated Circuit) technology. Since the plasma wave receiver needs to receive very weak signals in the various frequency ranges, it accommodates filters with different frequency responses, low noise amplifiers with high gains and oscillators. This leads to the large occupation of the board by the analogue circuits. Therefore, the breakthrough to the extreme miniaturization of the plasma wave receiver does not occur without the miniaturization of the analogue electronic circuit. We have already confirmed the feasibility in realizing six channels (three for electric fields and three for magnetic fields) of waveform receivers inside the small chip with the size of 3mm x 3mm. The developed waveform receiver shows the good feature enough for the use in scientific missions. This success in the miniaturization of plasma wave receivers allow us to develop a new system measuring plasma waves in multiple points. Based on the technology of the miniaturization of plasma wave receivers, we propose a new system for monitoring the electromagnetic environment in space. We address it MSEE (Monitor System for space Electromagnetic Environments). The MSEE is a kind of the sensor network system in space. It consists of palm-sized sensor nodes, which are randomly distributed in the target area. The sensor node carries a compact plasma wave receiver as well as other necessary components such as communications and digital processing units. The MSEE system resolves the disadvantage of the single-point (or a few points) observation in space missions. This is a very new concept for measuring the space electromagnetic environments. The important issue in the development of the MSEE is the design and development of the small sensor node. We developed the first prototype of the sensor node system. It contains the analogue ASIC of plasma wave receiver with small electric and magnetic sensors, small digital processing unit using the one-chip computer, small fluxgate sensor for the attitude detection, and GPS receiver for the location estimation. The system is controlled by the software running on the onboard one-chip computer. In the present paper, we report our design of the MSEE sensor node system as well as the development of the miniaturized plasma wave receivers. We also show the performance of our first prototype of the sensor node.

Kojima, Hirotsugu; Fukuhara, Hajime; Okada, Satoshi; Yagitani, Satoshi; Ikeda, Hirokazu; Miyake, Yohei; Usui, Hideyuki; Yamakawa, Hiroshi; Ueda, Yoshikatsu

2010-05-01

253

Analysis of Neptune's Stratospheric Haze Using High-Phase-Angle Voyager Images.  

National Technical Information Service (NTIS)

We have inverted high-phase-angle Voyager images of Neptune to determine the atmospheric extinction coefficient as a function of altitude and the scattering phase function at a reference altitude. Comparisons between theoretical model and observations hel...

J. I. Moses K. Rages J. B. Pollack

1995-01-01

254

46 CFR 185.220 - Records of a voyage resulting in a marine casualty.  

Code of Federal Regulations, 2011 CFR

...which a report is required under § 185.202 of this part shall retain all voyage records maintained by the vessel, including rough and smooth deck and engine room logs, bell books, navigation charts, navigation work books, compass deviation...

2011-10-01

255

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

256

Postcolonial Perspectives on Early Modern Canada: Champlain's Voyages de la Nouvelle France (1632)  

Microsoft Academic Search

The early modern dimension of francophone postcolonialism has yet to be fully explored. This paper adds historical depth to postcolonial studies by applying post-colonial theory to an early seventeenth-century French colonial text: Samuel de Champlain’s Voyages de la Nouvelle France (1632). A postcolonial reading of Champlain’s Voyages reveals the ambivalence latent in a text traditionally seen as a straightforward narrative

Ursula Haskins Gonthier

2012-01-01

257

Probing Very Bright End of Galaxy Luminosity Function at z >~ 7 Using Hubble Space Telescope Pure Parallel Observations  

NASA Astrophysics Data System (ADS)

We report the first results from the Hubble Infrared Pure Parallel Imaging Extragalactic Survey, which utilizes the pure parallel orbits of the Hubble Space Telescope to do deep imaging along a large number of random sightlines. To date, our analysis includes 26 widely separated fields observed by the Wide Field Camera 3, which amounts to 122.8 arcmin2 in total area. We have found three bright Y 098-dropouts, which are candidate galaxies at z >~ 7.4. One of these objects shows an indication of peculiar variability and its nature is uncertain. The other two objects are among the brightest candidate galaxies at these redshifts known to date (L>2L*). Such very luminous objects could be the progenitors of the high-mass Lyman break galaxies observed at lower redshifts (up to z ~ 5). While our sample is still limited in size, it is much less subject to the uncertainty caused by "cosmic variance" than other samples because it is derived using fields along many random sightlines. We find that the existence of the brightest candidate at z ? 7.4 is not well explained by the current luminosity function (LF) estimates at z ? 8. However, its inferred surface density could be explained by the prediction from the LFs at z ? 7 if it belongs to the high-redshift tail of the galaxy population at z ? 7. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs 11700 and 11702.

Yan, Haojing; Yan, Lin; Zamojski, Michel A.; Windhorst, Rogier A.; McCarthy, Patrick J.; Fan, Xiaohui; Röttgering, Huub J. A.; Koekemoer, Anton M.; Robertson, Brant E.; Davé, Romeel; Cai, Zheng

2011-02-01

258

Lick Jupiter-Voyager Reference Star Catalogue (Klemola+ 1978)  

NASA Astrophysics Data System (ADS)

The catalog 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 of Jovian satellites during the Jupiter flyby. The catalog contains accurate equatorial coordinates for equinox 1950.0, epoch 1978.27, photographic and visual magnitudes, AGK3 identifications and proper motions for 4983 stars. All of the reference stars are in the range 6h00m to 8h04m in right ascension (1950), declination zones +16 to +23 degrees, and 8h31m to 8h57m, zones +08 to +14 degrees. Mean errors of the positions are about 0.4 second of arc. Introduction The Lick Jupiter-Voyager Reference Star Catalogue. Klemola et al. (1978) 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 of Jovian satellites during the Jupiter flyby. The requirements were a surface density of three to four reference stars per observation frame of 24 sq. arcmin. of the cameras - somewhat greater than that provided by the AGK3 catalog (Dieckvoss et al. 1975) - and a positional accuracy approximately 0.5. Visual magnitudes were also required. The completed catalog contains 4983 stars in the right ascension ranges 6h00m to 8h04m, declination zones +16 deg. to +23 deg., and 8h31m to 8h57m, declination zones +08 deg. to +14 deg.. Mean errors of the positions, as derived from least squares solutions against the AGK3 reference stars, are about 0.4"; however, individual residuals are fairly numerous in the range 0.6" to 0.8" with some in the range 1.0" to 1.3" The accidental error of one measurement, as deduced from a tabular histogram given in the original catalog publication (referenced below), is about 0.11". Apparent photographic and visual magnitudes were derived from iris photometer measurements, m(v). being approximated from a derived color-index relation using the AGK3 reference stars. The resulting magnitudes appear to have mean errors of at least 0.2 mag while very blue and very red stars (C.I..le.0 mag, and C.I..ge.1.5, respectively) are less certain. The magnitudes are considered to be only approximate (residuals of approximately 0.5 mag are fairly common). For additional information concerning the observations and reductions, the original publication (available from A. R. Klemola) should be consulted. A copy of this document should be transmitted to any recipient of the machine-readable catalog. (1 data file).

Klemola, A. R.; Morabito, L.

1996-04-01

259

Deep space navigation systems and operations  

Microsoft Academic Search

The history of the deep space navigation system developed by NASA is outlined. Its application to Mariner, Viking and Pioneer missions is reviewed. Voyager navigation results for Jupiter and Saturn are commented on and velocity correction in relation to fuel expenditure and computer time are discussed. The navigation requirements of the Gahleo and Venus orbiting imaging radar (VOIR) missions are

J. F. Jordan

1981-01-01

260

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

NASA Astrophysics Data System (ADS)

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 ??:?r = 3:1, where ?? and ?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

2012-09-01

261

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.

262

Evidence for a Shock in Interstellar Plasma: Voyager 1  

NASA Astrophysics Data System (ADS)

Voyager 1 (V1) observed electron plasma oscillations preceding a jump by a factor of 1.4 in the magnetic field intensity B near the end of 2012. The frequency of the electron plasma oscillations gives an electron density ne = 0.05 cm–3, which implies that V1 was immersed in plasma from the interstellar medium. The last day on which plasma oscillations were observed is day 332, 2012, and the jump in the B was centered on day 335, 2012 after a data gap in the wave data. The close association between the electron plasma oscillations and the jump in B suggests a causal connection, such as that frequently observed between electron plasma oscillations and interplanetary shocks at 1 AU. Based on the observed parameters and the smooth profile of B(t), the jump in B appears to be associated with a weak, subcritical, laminar, low beta, quasi-perpendicular, resistive, collisionless shock. However, the width of the jump is of the order of 104 times that expected for such a stationary shock at 1 AU. The large width of the jump in B might be the result of differences between the structure of shocks in the interstellar medium and the plasma near 1 AU. Alternatively, the subcritical resistive shock might have decayed during a few days after producing the plasma waves, leaving a broad profile in B(t) without significantly changing ambient parameters. Another possibility is that the jump in B is a pressure wave.

Burlaga, L. F.; Ness, N. F.; Gurnett, D. A.; Kurth, W. S.

2013-11-01

263

Space 2000. Meeting the challenge of a new era  

Microsoft Academic Search

Contents: Part I: Voyaging into orbit and beyond. 1. Challenger. 2. NASA and its foreign competitors in the 1980s. 3. Highways to heaven.Part II: The practical uses of space. 4. Communications satellites. 5. The orbital high ground: weather watching, spying and star wars. 6. Earth science: a global view of a green planet. 7. Materials processing in space: making pie

H. L. Shipman

1987-01-01

264

Icy Moon Absorption Signatures: Probes of Saturnian Magnetospheric Dynamics and Moon Activity  

Microsoft Academic Search

After the first flybys at the outer planets by the Pioneer and Voyager probes, it became evident that energetic charged particle absorption features in the radiation belts are important tracers of magnetospheric dynamical features and parameters. Absorption signatures are especially important for characterizing the Saturnian magnetosphere. Due to the spin and magnetic axes' near-alignment, losses of particles to the icy

E. Roussos; N. Krupp; G. H. Jones; C. Paranicas; D. G. Mitchell; S. M. Krimigis; U. Motschmann; M. K. Dougherty; A. Lagg; J. Woch

2006-01-01

265

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

266

The extension of the Cassini spacecraft\\/Titan probe to the exploration of Neptune\\/Triton  

Microsoft Academic Search

NASA and ESA are planning a mission named 'Cassini' to place a spacecraft in Saturn orbit and deposit an atmospheric probe into the atmosphere of Titan. It is expected that the upcoming close flyby of Neptune and Triton by Voyager 2 will increase future scientific interest in more intensive exploration of that system. The purpose of this paper is to

Paul F. Wercinski; Byron L. Swenson; Alfred C. Mascy; Ray T. Reynolds

1990-01-01

267

PROBING VERY BRIGHT END OF GALAXY LUMINOSITY FUNCTION AT z {approx}> 7 USING HUBBLE SPACE TELESCOPE PURE PARALLEL OBSERVATIONS  

SciTech Connect

We report the first results from the Hubble Infrared Pure Parallel Imaging Extragalactic Survey, which utilizes the pure parallel orbits of the Hubble Space Telescope to do deep imaging along a large number of random sightlines. To date, our analysis includes 26 widely separated fields observed by the Wide Field Camera 3, which amounts to 122.8 arcmin{sup 2} in total area. We have found three bright Y{sub 098}-dropouts, which are candidate galaxies at z {approx}> 7.4. One of these objects shows an indication of peculiar variability and its nature is uncertain. The other two objects are among the brightest candidate galaxies at these redshifts known to date (L>2L*). Such very luminous objects could be the progenitors of the high-mass Lyman break galaxies observed at lower redshifts (up to z {approx} 5). While our sample is still limited in size, it is much less subject to the uncertainty caused by 'cosmic variance' than other samples because it is derived using fields along many random sightlines. We find that the existence of the brightest candidate at z {approx} 7.4 is not well explained by the current luminosity function (LF) estimates at z {approx} 8. However, its inferred surface density could be explained by the prediction from the LFs at z {approx} 7 if it belongs to the high-redshift tail of the galaxy population at z {approx} 7.

Yan Haojing [Center for Cosmology and AstroParticle Physics, The Ohio State University, 191 West Woodruff Avenue, Columbus, OH 43210 (United States); Yan Lin; Zamojski, Michel A. [Spitzer Science Center, California Institute of Technology, MS 220-6, Pasadena, CA 91125 (United States); Windhorst, Rogier A. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); McCarthy, Patrick J. [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Fan Xiaohui; Dave, Romeel [Astronomy Department, The University of Arizona, Tucson, AZ 85721 (United States); Roettgering, Huub J. A. [Leiden Observatory, University of Leiden, P.O. Box 9513, Leiden 2300 RA (Netherlands); Koekemoer, Anton M. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Robertson, Brant E. [Astronomy Department, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States); Cai Zheng [Physics Department, The University of Arizona, Tucson, AZ 85721 (United States)

2011-02-10

268

Probing the haze in the atmosphere of HD 189733b with Hubble Space Telescope/WFC3 transmission spectroscopy  

NASA Astrophysics Data System (ADS)

We present Hubble Space Telescope near-infrared transmission spectroscopy of the transiting exoplanet HD 189733b, using the Wide Field Camera 3 (WFC3). This consists of time series spectra of two transits, used to measure the wavelength dependence of the planetary radius. These observations aim to test whether the Rayleigh scattering haze detected at optical wavelengths extends into the near-infrared, or if it becomes transparent leaving molecular features to dominate the transmission spectrum. Due to saturation and non-linearity affecting the brightest (central) pixels of the spectrum, light curves were extracted from the blue and red ends of the spectra only, corresponding to wavelength ranges of 1.099-1.168 and 1.521-1.693 ?m, respectively, for the first visit, and 1.082-1.128 and 1.514-1.671 ?m for the second. The light curves were fitted using a Gaussian process model to account for instrumental systematics whilst simultaneously fitting for the transit parameters. This gives values of the planet-to-star radius ratio for the blue and red light curves of 0.156 50 ą 0.000 48 and 0.156 34 ą 0.000 32, respectively, for visit 1 and 0.157 16 ą 0.000 78 and 0.156 30 ą 0.000 37 for visit 2 (using a quadratic limb-darkening law). The planet-to-star radius ratios measured in both visits are consistent, and we see no evidence for the drop in absorption expected if the haze that is observed in the optical becomes transparent in the infrared. This tentatively suggests that the haze dominates the transmission spectrum of HD 189733b into near-infrared wavelengths, although more robust observations are required to provide conclusive evidence.

Gibson, N. P.; Aigrain, S.; Pont, F.; Sing, D. K.; Désert, J.-M.; Evans, T. M.; Henry, G.; Husnoo, N.; Knutson, H.

2012-05-01

269

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

270

Probing the steric space at the floor of the D1 dopamine receptor orthosteric binding domain: 7?-, 7?-, 8?-, and 8?-methyl substituted dihydrexidine analogues  

PubMed Central

To probe the space at the floor of the orthosteric ligand binding site in the dopamine D1 receptor, four methylated analogs of dihydrexidine (DHX) were synthesized with substitutions at the 7 and 8 positions. The 8?-axial, 8?-equatorial and 7?-equatorial were synthesized by photochemical cyclization of appropriately substituted N-benzoyl enamines, the 7?-axial analog was prepared by an intramolecular Henry reaction. All of the methylated analogs displayed losses in affinity when compared to DHX (20 nM): 8?-Meax-DHX (270 nM), 8?-Meeq-DHX (920 nM), 7?-Meeq-DHX (6540 nM), and 7?-Meax-DHX (>10000 nM). Molecular modeling studies suggest that although the disruption of an aromatic interaction between Phe2035.47 and Phe2886.51 is the cause for the 14-fold loss in affinity associated with 8?-axial substitution, unfavorable steric interactions with Ser1073.36 result in the more dramatic decreases in binding affinity suffered by the rest of the analogs.

Cueva, Juan Pablo; Gallardo-Godoy, Alejandra; Juncosa, Jose I.; Vidi, Pierre A.; Lill, Markus A.; Watts, Val J.; Nichols, David E.

2011-01-01

271

ALEX neutral beam probe  

SciTech Connect

A neutral beam probe capable of measuring plasma space potential in a fully 3-dimensional magnetic field geometry has been developed. This neutral beam was successfully used to measure an arc target plasma contained within the ALEX baseball magnetic coil. A computer simulation of the experiment was performed to refine the experimental design and to develop a numerical model for scaling the ALEX neutral beam probe to other cases of fully 3-dimensional magnetic field. Based on this scaling a 30 to 50 keV neutral cesium beam probe capable of measuring space potential in the thermal barrier region of TMX Upgrade was designed.

Pourrezaei, K.

1982-01-01

272

Determination of the solution-bound conformation of an amino acid binding protein by NMR paramagnetic relaxation enhancement: use of a single flexible paramagnetic probe with improved estimation of its sampling space.  

PubMed

We demonstrate the feasibility of elucidating the bound ("closed") conformation of a periplasmic binding protein, the glutamine-binding protein (GlnBP), in solution, using paramagnetic relaxation enhancements (PREs) arising from a single paramagnetic group. GlnBP consists of two globular domains connected by a hinge. Using the ligand-free ("open") conformation as a starting point, conjoined rigid-body/torsion-angle simulated annealing calculations were performed using backbone (1)H(N)-PREs as a major source of distance information. Paramagnetic probe flexibility was accounted for via a multiple-conformer representation. A conventional approach where the entire PRE data set is enforced at once during simulated annealing yielded poor results due to inappropriate conformational sampling of the probe. On the other hand, significant improvements in coordinate accuracy were obtained by estimating the probe sampling space prior to structure calculation. Such sampling is achieved by refining the ensemble of probe conformers with intradomain PREs only, keeping the protein backbone fixed in the open form. Subsequently, while constraining the probe to the previously found conformations, the domains are allowed to move relative to each other under the influence of the non-intradomain PREs, giving the hinge region torsional degrees of freedom. Thus, by partitioning the protocol into "probe sampling" and "backbone sampling" stages, structures significantly closer to the X-ray structure of ligand-bound GlnBP were obtained. PMID:19583434

Bermejo, Guillermo A; Strub, Marie-Paule; Ho, Chien; Tjandra, Nico

2009-07-15

273

46 CFR 35.15-1 - Notice and reporting of casualty and voyage records-TB/ALL.  

Code of Federal Regulations, 2012 CFR

... false Notice and reporting of casualty and voyage records-TB/ALL. 35.15-1 Section 35.15-1 Shipping COAST...15-1 Notice and reporting of casualty and voyage recordsâTB/ALL. The requirements for providing notice and...

2012-10-01

274

Energetic Proton and Electron Distributions in Saturn Magnetosphere as Revealed by Cassini \\/ Voyager Observations and Proposed by Models  

Microsoft Academic Search

Before the arrival of Cassini at Saturn in July 2004, our knowledge of energetic protons and electrons (energy > 10 KeV) in Saturn's magnetosphere, radial distances r < 12 Rs was mainly based on the particle observations made during the flybys of Pioneer 11 (September 1979), Voyager 1 (November 1980), and Voyager 2 (August 1981). Models of radiation belts have

S. J. Bolton; D. Santos-Costa; N. Krupp; M. Dougherty; E. Roelof; D. G. Mitchell; R. M. Thorne; M. Blanc

2004-01-01

275

Space Environment Measurements for Icy Surfaces in the Solar System and Beyond  

NASA Astrophysics Data System (ADS)

There are dozens of icy satellites orbiting the giant planets and trillions of icy comets populating the Kuiper Belt and Oort Cloud. Such objects are likely to be common throughout other planetary systems, particularly those now known to have giant plants. Interactions of the local space environment with these bodies must be taken in account for proper interpretation of photometric and spectroscopic measurements related to surface composition. Most of these bodies either are known to have, or likely have, tenuous atmospheres of volatile gases produced by internal outgassing and surface sublimation, sputtering from charged particle and UV irradiation, and diffuse dust clouds produced from meteoritic impacts. Whether or not Pluto counts as a small icy planet or a big comet, its thin and variable atmosphere also allows direct surface exposure to the space environment. Even glacial ices on the surface of (e.g., Snowball) Earth may have been exposed to much of the interplanetary solar UV flux at early times when an effective ozone shield was absent, and the Mars atmosphere is thin enough today for direct irradiation of polar cap ices by high energy cosmic ray and solar flare ions. Planetary magnetic fields reduce exposure to interplanetary charged particles but add irradiation by magnetospheric plasma and energetic particles. At Europa the intense surface irradiation from the Jovian magnetosphere might play a role via radiolytic chemistry in possible evolution of life within the putative sub-surface ocean. Although an armada of spacecraft have been measuring for many years the parameters of the solar UV, plasma, energetic particle, and dust environments of rocky bodies, large and small, in the inner solar system near Earth's orbit around the Sun, only six spacecraft with varying capabilities (Pioneer 10/11, Voyager 1/2, Galileo Orbiter, Cassini Orbiter) have yet ventured into the domain of the icy bodies near and beyond the orbit of Jupiter. The first five have collectively provided extensive measurements on the high flux plasma and energetic particle radiation environments of the jovian and saturnian magnetospheres, and the sixth will arrive to begin a long orbital tour of the Saturn system in July 2004. For the Uranus and Neptune systems we have the Voyager 2 flyby data sets. Extensive interplanetary measurements beyond Jupiter's orbit have only been provided by the Pioneer and Voyager missions into the 30 - 60 AU region of observable Kuiper Belt Objects (KBO). Of particular note are the recent report of dust in the outer solar system from interstellar grain impacts on KBOs, which may be relevant to observed color diversity of these objects, and the likely emergence of the Voyager 1 spacecraft into the heliosheath region of the heliosphere within the next eleven-year solar cycle if not in the next few years. The solar wind termination shock now sought by Voyager 1 marks the inner boundary of the heliosheath where outward solar wind flow slows down. The heliopause at a few times that shock distance in AU is the outer contact boundary for entry into the local interstellar plasma and cosmic ray environment of the outer Kuiper Belt at about 100 - 1000 AU and the Oort Cloud extending out to 100,000 AU. Interestingly, an increasing number of Scattered Kuiper Belt Objects in highly eccentric solar orbits are being detected near their perihelia with aphelia ranging out to 1000 AU, and these objects cumulatively experience different effects of space weathering in multiple heliospheric regions. The planned New Horizons and Interstellar Probe missions will further extend environmental measurements into the varying environmental domains of Pluto and the KBOs.

Cooper, J. F.

2002-12-01

276

Has the configuration of Jupiter's polar aurora changed significantly since the Voyager epoch?  

NASA Astrophysics Data System (ADS)

At Earth, over 70 percent of auroral power during active periods resides within the diffuse auroral components, despite the disproportionate interest in discrete auroral processes. At Jupiter, present day interest also resides overwhelmingly on discrete auroral processes associated with field-aligned currents driven by planetary rotation. However, during the Voyager epoch of 1979 through the 1980's, interest was focused elsewhere. It was believed that bright aurora of Jupiter extend in latitude down to the vicinity of the magnetic footprints of the plasma torus of Io, based on Voyager ultraviolet spectrometer (UVS) observations. And, it was believed that diffuse auroral processes generate this Io-associated aurora, specifically with the precipitation of energetic ions, most importantly S and O. Ion energy intensities were measured sufficient to deliver about 60 ergs per square cm over the 7 to 9 RJ region with strong wave scattering, sufficient to deliver about 30 trillion W of energy. Since that time (beginning in the early 1990's), near-Earth imaging of the aurora has revealed that the brightest aurora of Jupiter typically occurs on field lines that map along field lines to between 20 and 30 RJ, and certainly no closer to Jupiter than 15 RJ. Discussions of the differences between Voyager and more recent observations have focused on the limitations of the Voyager measurements. However, the particles that were identified during the Voyager epoch as being responsible for the bright aurora are just the same particles that in 1995 were observed by Galileo to have been dramatically depleted, by a factor of 5 in total energy density and perhaps even more for heavy ions. Could the change in the perceived configuration of the aurora since the Voyager epoch represent a true change in the configuration of Jupiter's magnetosphere? Specifically, has a key component of Jupiter's aurora, the diffuse component, dimmed dramatically since that epoch? Here we update the evidence that the configuration of Jupiter's magnetosphere has changed by showing that the depletion of the near-torus energetic ion populations have persisted and probably substantially deepened in more recent times. We review concurrent evidence that the depletion of the energetic ions is caused by enhancements in the neutral gases emanating from Io since the Voyager epoch. We argue that following the Voyager epoch, Jupiter's aurora may have become even less Earth-like than it is now in terms of the balance between diffuse and discrete components, and that the volcanoes of Io have a here-to-fore unappreciated role in establishing that balance.

Mauk, B. H.

2004-12-01

277

Study of solar wind dynamics using five spacecraft simultaneous measurements: Helios, Voyagers and IMP 8  

NASA Astrophysics Data System (ADS)

We analyzed in-situ measurements of five spacecraft: Helios 1, Helios 2, IMP 8, Voyager 1 y Voyager 2, from November 1977 to February 1978 (ascending phase of solar cycle 21). In this interval, the five spacecraft were located within angular region less to 60 degrees, conforming a unique multi-spacecraft set to study the large-scale dynamics of the solar wind. We identify 12 events: 7 interplanetary coronal mass ejections (ICMEs) and 5 stream interaction regions (SIRs). We present a qualitative and quantitative description of the 12 events to analyzed their structure and heliocentric evolution.

Romero Hernandez, E.; Gonzalez-Esparza, A.

2010-12-01

278

Space weather and deep space communications  

Microsoft Academic Search

While Pioneer 11 and Galileo are two deep space missions that experienced radio communication disruptions due to space weather, the success of a mission like Solar Probe, whose goal is to fly by the Sun within a few solar radii of its surface, may depend critically on space weather. It is therefore crucial to thoroughly understand how space weather affects

Richard Woo

2007-01-01

279

Radio science investigations of the saturn system with voyager 1: preliminary results.  

PubMed

Voyager 1 radio occultation measurements of Titan's equatorial atmosphere successfully probed to the surface, which is provisionally placed at a radius of 2570 kilometers. Derived scale heights plus other experimental and theoretical results indicate that molecular nitrogen is the predominant atmospheric constituent. The surface pressure and temperature appear to be about 1.6 bars and 93 K, respectively. The main clouds are probably methane ice, although some condensation of nitrogen cannot be ruled out. Solar abundance arguments suggest and the measurements allow large quantities of surface methane near its triple-point temperature, so that the three phases of methane could play roles in the atmosphere and on the surface of Titan similar to those of water on Earth. Radio occultation measurements of Saturn's atmosphere near 75 degrees south latitude reached a maximum pressure of 1.4 bars, where the temperature is about 156 K. The minimum temperature is about 91 K near the 60-millibar pressure level. The measured part of the polar ionosphere of Saturn has a peak electron concentration of 2.3 x 10(4) per cubic centimeter at an altitude of 2500 kilometers above the 1-bar level in the atmosphere, and a plasma scale height at the top of the ionosphere of 560 kilometers. Attenuation of monochromatic radiation at a wavelength of 3.6 centimeters propagating obliquely through Saturn's rings is consistent with traditional values for the normal optical depth of the rings, but the near-forward scattering of this radiation by the rings indicates effective scattering particles with larger than expected diameters of 10, 8, and 2 meters in the A ring, the outer Cassini division, and the C ring, respectively. Preliminary analysis of the radio tracking data yields new values for the masses of Rhea and Titan of 4.4 +/- 0.3 x 10(-6) and 236.64 +/- 0.08 x 10(-6) times the mass of Saturn. Corresponding values for the mean densities of these objects are 1.33 +/- 0.10 and about 1.89 grams per cubic centimeter. The density of Rhea is consistent with a solar-composition mix of anhydrous rock and volatiles, while Titan is apparently enriched in silicates relative to the solar composition. PMID:17783830

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

1981-04-10

280

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

281

Chronicles of the Sea: The History and Literature of Man's Voyages.  

ERIC Educational Resources Information Center

|In spring 1984, an interdisciplinary course on the history and literature of man's voyages and relationship with the sea was introduced at J. Sargeant Reynolds Community College (JSRCC). The course was team taught from the perspectives of the social sciences and English departments, incorporating fiction and non-fiction sources related to…

Roderer, Lawrence C.; Lacy, Richard

282

Jupiter's Decametric and Hectometric Radio Emissions Observed by Cassini RPWS and Voyager PRA  

NASA Astrophysics Data System (ADS)

The relationship between Jupiter's decametric (DAM) and hectometric (HOM) radio emissions is important to help understand the emission mechanism that both of them have in common, but it has remained an elusive enigma. We have investigated Jovian DAM and HOM emissions observed by the Cassini, Voyager 1 and Voyager 2 spacecraft. We made a statistical comparison of Cassini and combined Voyager 1 and 2 data for occurrence probability histograms in Central Meridian Longitude (CML) and in Io phase from 2 to 16 MHz, and a statistical analysis of Jovian HOM polarization plotted as a function of Jovian magnetic latitude and frequency below 3 MHz based on only the Cassini data. We found that (1) the position of Source B shows shifts in longitude from 10 to 16 MHz as seen in both Cassini and combined Voyager 1 and 2 data, (2) the effect of Io can be seen down to 4 MHz, (3) the occurrence probability of HOM emissions are separated into right- and left-hand polarization senses, and (4) attenuation bands make a large contribution to intensify the HOM emissions around the attenuated regions.

Imai, M.; Lecacheux, A.; Imai, K.; Higgins, C. A.; Thieman, J. R.

283

Gravity field of the Saturnian system from Pioneer and Voyager tracking data  

Microsoft Academic Search

Doppler-tracking data and star-satellite imaging from the Voyager 1 and 2 spacecraft are used along with Pioneer 11 Doppler tracking data to study the gravity field of the Saturnian system. The present analysis has yielded improved values for the masses of Rhea, Titan, and Iapetus, and Saturn. The results are consistent with the findings of Null et al. (1981) and

J. K. Campbell; J. D. Anderson

1989-01-01

284

Nature and evolution of magnetohydrodynamic fluctuations in the solar wind: Voyager observations  

Microsoft Academic Search

The magnetic field and plasma data collected by the Voyager spacecraft between 1 and 11 AU are used to study the properties of interplanetary MHD fluctuations and to attempt to answer several related questions about the Alfvenicity of solar wind fluctuations; First, to what extent are magnetic and velocity fluctuations Alfvenic. Second, does the dominant propagation direction of Alfvenic fluctuations

D. A. Roberts; L. W. Klein; M. L. Goldstein; W. H. Matthaeus

1987-01-01

285

Synoptic observations of Jupiter's radio emissions: average statistical properties observed by voyager  

Microsoft Academic Search

Observations of Jupiter's low-frequency radio emission collected over one-month intervals before and after each Voyager encounter have been analyzed to provide a synoptic view of the average statistical properties of the emissions. Compilations of occurrence probability, average power flux density, and average sense of circular polarization are presented as a function of central meridian longitude, phase of Io, and frequency.

J. K. Alexander; T. D. Carr; J. R. Thieman; J. J. Schauble; A. C. Riddle

1981-01-01

286

3D R&D technology for the future voyage in Japan  

Microsoft Academic Search

Present a collection of slides covering the following topics: 3D R&D technology for the future voyage in Japan; Moore's law limitation and possible technology solutiuons; 3DIC (dream chip) application fields: healthcare and biology, futuristic robots, advanced consumer electronics, and laptop supercomputers; communication; ubiquitous computing, autopilot for cars; capsule for inspection by CCD or CMOS camera; capsule for inspection, medication &

K. Inagaki

2010-01-01

287

Stratospheric Images of Jupiter Derived from Hydrocarbon Emissions in Voyager 1 and 2 IRIS Spectra  

NASA Astrophysics Data System (ADS)

Spectroscopic data obtained by the Infrared Interferometer Spectrometer (IRIS) aboard Voyager 1 and 2 have been re-visited. Using the spectroscopic data and footprints of the IRIS aperture on the planet, we constructed images of the stratosphere of Jupiter at the emission bands of hydrocarbons including CH4, C2H6, C2H2, C3H4, C6H6, and C2H4. Thermal emission from the hydrocarbons on Jupiter originates from a broad region of the stratosphere extending from 1 to 10 millibars. We averaged the data using a bin of 20 degrees of longitude and latitudes in order to increase signal-to-noise ratios. The resultant images show interesting wave structure in Jupiter's stratosphere. Fourier transform analyses of these images yield wavenumbers 5 - 7 at mid-Northern and mid-Southern latitudes, and these results are different from those resulted from previous ground-based observations and recent Cassini CIRS, suggesting temporal variations on the stratospheric infrared pattern. The comparisons of the Voyager 1 and 2 spectra also show evidence of temporal intensity variations not only on the infrared hydrocarbon polar brightenings of hydrocarbon emissions but also on the stratospheric infrared structure in the temperate regions of Jupiter over the 4 month period between the two Voyager encounters. Short running title: Stratospheric Images of Jupiter derived from Voyager IRIS Spectra.

Seo, Haingja; Kim, Sang Joon; Choi, W. K.; Kostiuk, T.; Bjoraker, G.

2005-12-01

288

Worlds Apart: Context, Voyages and Encounters in the Age of Exploration. Updated Edition.  

ERIC Educational Resources Information Center

This curriculum unit offers students the opportunity to become researchers of history. The curriculum is organized among three sections: (1) "Context," students are introduced to early seagoing peoples, their ideas and technologies, and to related ideas from Renaissance Europe; (2) "Voyages," students conduct individual research projects about the…

Roelofs, Anna; Millstone, David

289

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

290

Smart Voyage Planning Model Sensitivity Analysis Using Ocean and Atmospheric Models Including Ensemble Methods.  

National Technical Information Service (NTIS)

Smart Voyage Planning (SVP) has been identified as a key technology for the US Navy, capable of assisting with the fleet energy saving goals of Secretary of the Navy (SECNAV) and the Chief of Naval Operations (CNO). Commercial SVP tools use weather, waves...

S. E. Miller

2012-01-01

291

Data from NASA Rover's Voyage to Mars Aids Planning  

NASA Website

Measurements taken by NASA's Mars Science Laboratory mission as it delivered the Curiosity rover to Mars in 2012 are providing NASA the information it needs to design systems to protect human explorers from radiation exposure on deep-space ...

292

Comparison between Cassini and Voyager observations of Jupiter's decametric and hectometric radio emissions  

NASA Astrophysics Data System (ADS)

In this paper, we attempt to clarify the relationship between Jovian hectometric (HOM) and non-Io-related decametric (non-Io-DAM) radio structure. For that purpose, we extend the analysis by including more data and investigating statistical properties of the Jovian DAM and HOM radio emissions based on Cassini and Voyager observations, especially below 16 MHz. We have investigated these emissions observed by the Cassini, Voyager 1, and Voyager 2 spacecraft for specific Jovigraphic latitudes in the range of -3.7°-7.3° and local times in the range of 0.76-21.4 hours. We show a statistical comparison of Cassini, Voyager 1, and Voyager 2 data for occurrence probability in Central Meridian Longitude (CML) versus Io phase and in CML versus Frequency. The main results are as follows: (1) the detailed frequency structures of non-Io-related components can be seen for different spacecraft's local time and Jovigraphic latitude, (2) the high frequency of HOM extends up to near 10 MHz, and (3) a new DAM component, named the non-Io-D, appears from 40° to 60° CML in the frequency range of 7-11 MHz. On the basis of additional information of different behaviors of non-Io-B and non-Io-A structures in longitude depending on pre- and post-encounter of Cassini data, we improved the DAM angular beaming model that shows the cone half-angle of the emitting cone decreases as a function of frequency. We conclude that the changing beaming angle is not affected by Jovigraphic latitude of the spacecraft, but rather due to different local time of the source regions.

Imai, Masafumi; Imai, Kazumasa; Higgins, Charles A.; Thieman, James R.

2011-12-01

293

Saturn's A Ring Now and Then: a Comparison of Voyager IRIS and Cassini CIRS Observations  

NASA Astrophysics Data System (ADS)

During Cassini's successful orbital insertion manuever at Saturn earlier this summer its Composite Infrared Spectrometer (CIRS) obtained thermal spectra of Saturn's ring system at range of geometries not seen since the Voyager flybys. CIRS is a Fourier-transform spectrometer that measures infrared radiation from 7 microns out to 1 millimeter (1400 to 10 cm-1 ). Among the main rings, the A Ring was observed at the greatest range of phase angles and emission angles during Saturn orbit insertion. Scans of the lit and unlit sides of the A Ring were obtained at a spectral resolution of 15.5 cm-1 and at low ( ˜ 60o ) and intermediate ( ˜ 130o -- 140o ) phase angles. The infrared interferometer spectrometer (IRIS) experiments aboard Voyagers 1 and 2 also obtained thermal spectra of the rings. IRIS, the predecessor of the CIRS instrument, is a Michelson interferometer that records spectra between 4 and 55.5 ? m (2500 to 180 cm-1 ). Useful spectra of the lit and unlit A Ring with a resolution of 4.3 cm-1 were obtained during the Voyager flybys at phase angles somewhat lower than CIRS SOI scans ( ˜ 30o ) and at intermediate phase angles comparable to those observed by CIRS. We will present and interpret Cassini observations of the A Ring in the context of the earlier Voyager observations. The range in viewing geometries provided by the two sets of observations yields leverage in determining physical properties of the ring as a whole as well as its constituent particles. Additionally, the separation in time between the two sets of observations will allow us to identify any changes in ring temperatures between the Voyager and Cassini epochs as might be expected from, for example, differences in solar elevation angle.

Brooks, S. M.; Spilker, L. J.; Pilorz, S. H.; Edgington, S. G.; Wallis, B. D.; Pearl, J. C.; Flasar, F. M.; Ferrari, C.; Showalter, M. R.; Achterberg, R. K.; Nixon, C. A.; Simon-Miller, A. A.; Romani, P. N.; CIRS Investigation

2004-11-01

294

Automating Deep Space Network scheduling and conflict resolution  

Microsoft Academic Search

The missions supported by the DSN include all of NASA's deep space missions, such as the planetary exploration spacecraft at Mars (the Mars Exploration Rovers Spirit and Opportunity, Mars Odyssey, Mars Global Surveyor) and Saturn (Cassini-Huygens); cometary explorers such as Deep Impact and Stardust; and missions such as Voyagers 1 and 2 that are leaving the solar system entirely. Other

Mark D. Johnston; Bradley J. Clement

2006-01-01

295

Quantum-cryptographic entangling probe  

SciTech Connect

For a general entangling probe attacking the Bennett-Brassard 1984 protocol in quantum key distribution, I calculate three classes of optimized unitary transformations, all yielding the same maximum information to the probe. The simplest one corresponds to a probe having a two-dimensional Hilbert space of states, and is uniquely determined by the error rate induced by the probe in the legitimate receiver. The second class corresponds to a probe having a four-dimensional Hilbert space of states, and is determined by the error rate and two continuous angle parameters which are mutually constrained by the error rate. The third class corresponds to a probe having a four-dimensional Hilbert space, and is determined by the error rate and two continuous angle parameters, one of which is constrained by the error rate. Furthermore, I show that the simplest quantum circuit representing the optimal entangling probe consists of a single controlled-NOT gate in which the control qubit consists of two polarization-basis states of the signal, the target qubit consists of two probe-basis states, and the initial state of the probe is set by the error rate. A method is determined for measuring the appropriate correlated state of the probe. Finally, a possible implementation of the entangling probe is described.

Brandt, Howard E. [U.S. Army Research Laboratory, Adelphi, Maryland 20783 (United States)

2005-04-01

296

Nuclear Power for deep space missions  

NASA Astrophysics Data System (ADS)

Nuclear Power enables exploratory missions into deep space, where solar insolation is too weak for Solar Power to be effective. Radioisotope powered deep space platforms such as Voyager have been used for many years. Fission powered satellite have been flown also, mainly by the USSR. However these are low power systems. The high powered fission option is developing in the USA. This offers much more power to mission and platform designers. It will enhance the electric propulsion option for deep space platforms and allow much more power intensive payloads to be deployed. This paper reviews the history of Space Nuclear Reactors and describes emerging systems.

Gardner, F. J.

1994-06-01

297

Charged Kaon Interferometric Probes of Space-Time Evolution in Au+Au Collisions at sNN=200GeV  

Microsoft Academic Search

Bose-Einstein correlations of charged kaons are used to probe Au+Au collisions at sNN=200GeV and are compared to charged pion probes, which have a larger hadronic scattering cross section. Three-dimensional Gaussian source radii are extracted, along with a one-dimensional kaon emission source function. The centrality dependences of the three Gaussian radii are well described by a single linear function of Npart1\\/3

S. Afanasiev; C. Aidala; N. N. Ajitanand; Y. Akiba; J. Alexander; A. Al-Jamel; K. Aoki; L. Aphecetche; R. Armendariz; S. H. Aronson; R. Averbeck; T. C. Awes; B. Azmoun; V. Babintsev; A. Baldisseri; K. N. Barish; P. D. Barnes; B. Bassalleck; S. Bathe; S. Batsouli; V. Baublis; F. Bauer; A. Bazilevsky; S. Belikov; R. Bennett; Y. Berdnikov; M. T. Bjorndal; J. G. Boissevain; H. Borel; K. Boyle; M. L. Brooks; D. S. Brown; D. Bucher; H. Buesching; V. Bumazhnov; G. Bunce; J. M. Burward-Hoy; S. Butsyk; S. Campbell; J.-S. Chai; S. Chernichenko; J. Chiba; C. Y. Chi; M. Chiu; I. J. Choi; T. Chujo; V. Cianciolo; C. R. Cleven; Y. Cobigo; B. A. Cole; M. P. Comets; P. Constantin; M. Csanád; T. Csörgo; T. Dahms; K. Das; G. David; H. Delagrange; A. Denisov; D. D'Enterria; A. Deshpande; E. J. Desmond; O. Dietzsch; A. Dion; J. L. Drachenberg; O. Drapier; A. Drees; A. K. Dubey; A. Durum; V. Dzhordzhadze; Y. V. Efremenko; J. Egdemir; A. Enokizono; H. En'Yo; B. Espagnon; S. Esumi; D. E. Fields; F. Fleuret; S. L. Fokin; B. Forestier; Z. Fraenkel; J. E. Frantz; A. Franz; A. D. Frawley; Y. Fukao; S.-Y. Fung; S. Gadrat; F. Gastineau; M. Germain; A. Glenn; M. Gonin; J. Gosset; Y. Goto; R. Granier de Cassagnac; N. Grau; S. V. Greene; M. Grosse Perdekamp; T. Gunji; H.-Ĺ. Gustafsson; T. Hachiya; A. Hadj Henni; J. S. Haggerty; M. N. Hagiwara; H. Hamagaki; H. Harada; E. P. Hartouni; K. Haruna; M. Harvey; E. Haslum; K. Hasuko; R. Hayano; M. Heffner; T. K. Hemmick; J. M. Heuser; X. He; H. Hiejima; J. C. Hill; R. Hobbs; M. Holmes; W. Holzmann; K. Homma; B. Hong; T. Horaguchi; M. G. Hur; T. Ichihara; K. Imai; M. Inaba; D. Isenhower; L. Isenhower; M. Ishihara; T. Isobe; M. Issah; A. Isupov; B. V. Jacak; J. Jia; J. Jin; O. Jinnouchi; B. M. Johnson; K. S. Joo; D. Jouan; F. Kajihara; S. Kametani; N. Kamihara; M. Kaneta; J. H. Kang; T. Kawagishi; A. V. Kazantsev; S. Kelly; A. Khanzadeev; D. J. Kim; E. Kim; Y.-S. Kim; E. Kinney; Á. Kiss; E. Kistenev; A. Kiyomichi; C. Klein-Boesing; L. Kochenda; V. Kochetkov; B. Komkov; M. Konno; D. Kotchetkov; A. Kozlov; P. J. Kroon; G. J. Kunde; N. Kurihara; K. Kurita; M. J. Kweon; Y. Kwon; G. S. Kyle; R. Lacey; J. G. Lajoie; A. Lebedev; Y. Le Bornec; S. Leckey; D. M. Lee; M. K. Lee; M. J. Leitch; M. A. L. Leite; H. Lim; A. Litvinenko; M. X. Liu; X. H. Li; C. F. Maguire; Y. I. Makdisi; A. Malakhov; M. D. Malik; V. I. Manko; H. Masui; F. Matathias; M. C. McCain; P. L. McGaughey; Y. Miake; T. E. Miller; A. Milov; S. Mioduszewski; G. C. Mishra; J. T. Mitchell; D. P. Morrison; J. M. Moss; T. V. Moukhanova; D. Mukhopadhyay; J. Murata; S. Nagamiya; Y. Nagata; J. L. Nagle; M. Naglis; T. Nakamura; J. Newby; M. Nguyen; B. E. Norman; R. Nouicer; A. S. Nyanin; J. Nystrand; E. O'Brien; C. A. Ogilvie; H. Ohnishi; I. D. Ojha; H. Okada; K. Okada; O. O. Omiwade; A. Oskarsson; I. Otterlund; K. Ozawa; D. Pal; A. P. T. Palounek; V. Pantuev; V. Papavassiliou; W. J. Park; S. F. Pate; H. Pei; J.-C. Peng; H. Pereira; V. Peresedov; D. Yu. Peressounko; C. Pinkenburg; R. P. Pisani; M. L. Purschke; A. K. Purwar; H. Qu; J. Rak; I. Ravinovich; K. F. Read; M. Reuter; K. Reygers; V. Riabov; Y. Riabov; G. Roche; A. Romana; M. Rosati; S. S. E. Rosendahl; P. Rosnet; P. Rukoyatkin; V. L. Rykov; S. S. Ryu; B. Sahlmueller; N. Saito; T. Sakaguchi; S. Sakai; V. Samsonov; H. D. Sato; S. Sato; S. Sawada; V. Semenov; R. Seto; D. Sharma; T. K. Shea; I. Shein; T.-A. Shibata; K. Shigaki; M. Shimomura; T. Shohjoh; K. Shoji; A. Sickles; C. L. Silva; D. Silvermyr; K. S. Sim; C. P. Singh; V. Singh; S. Skutnik; W. C. Smith; A. Soldatov; R. A. Soltz; W. E. Sondheim; S. P. Sorensen; I. V. Sourikova; F. Staley; P. W. Stankus; E. Stenlund; M. Stepanov; A. Ster; S. P. Stoll; T. Sugitate; C. Suire; J. P. Sullivan; J. Sziklai; T. Tabaru; S. Takagi; E. M. Takagui; A. Taketani; K. H. Tanaka; Y. Tanaka; K. Tanida; M. J. Tannenbaum; A. Taranenko; P. Tarján; T. L. Thomas; M. Togawa; J. Tojo; H. Torii; R. S. Towell; V.-N. Tram; I. Tserruya; Y. Tsuchimoto; S. K. Tuli; H. Tydesjö; N. Tyurin; C. Vale; H. Valle; H. W. van Hecke; J. Velkovska; R. Vértesi; A. A. Vinogradov; E. Vznuzdaev; M. Wagner; X. R. Wang; Y. Watanabe; J. Wessels; S. N. White; N. Willis; D. Winter; C. L. Woody; M. Wysocki; W. Xie; A. Yanovich; S. Yokkaichi; G. R. Young; I. Younus; I. E. Yushmanov; W. A. Zajc; O. Zaudtke; C. Zhang; J. Zimányi; L. Zolin

2009-01-01

298

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

299

Educational space probe model system of lander (Hunveyor), rover (Husar) and test-terrain for planetary science education and analog studies in universities and colleges of Hungary.  

NASA Astrophysics Data System (ADS)

In 1997 we began a complex modelling program in planetary geology unifying field work robotics, electronics and complex environmental analysis by constructing an experimental space probe model system. It consists of an experimental lander HUNVEYOR (Hungarian UNiversity surVEYOR), a rover named HUSAR (Hungarian University Surface Analyser Rover) and a test terrain. For Hunveyor the idea and example was the historical Surveyor program of NASA in the 1960-ies, for the Husar the idea and example was the Pathfinder's rover Sojouner rover. The main goals of this program are: 1) to teach the complex work of planetary science according to the main operations of the procedure of the large scientific and technology system, 2) to build the lander structure and basic electronics from cheap everyday PC compatible elements, 3) to construct basic experiments and their instruments, 4) to use the system as a space activity simulator, 5) to form the electronics of this simulator system which contains lander (with on board computer) for works on a test planetary surface, and a "terrestrial control" computer, "talking" with each other, 6) to harmonize the assemblage of the electronic system and instruments in various levels of autonomy from the power and communication circuits, 7) to use the complex system in education for in situ understanding of the complex planetary environmental problems, 8) to build various planetary environments on the test terrain in order to apply the instrument assemblages in various testing conditions, 9) to use the model system with special internet connections capable of communicating in the web in field trip conditions for users, and 10) to use the model system in real planetary analog field trip simulations, first in Hungary and later in some planetary analog site in the world. We report some of these visits in Hungary and Utah, USA. REFERENCES: [1] Bérczi Sz., Cech V., Hegyi S., Borbola T., Diósy T., Köll? Z., o 1 Tóth Sz. (1998): LPSC XXIX, #1267; [2] Drommer B., Blénessy G., Hanczár G., Gránicz K., Diósy T., Tóth Sz., Bodó E. (1999): LPSC XXX, #1606; [3] Bérczi Sz., Drommer B., Cech V., Hegyi S., Herbert J., Tóth Sz., Diósy T., Roskó F., Borbola T. (1999): LPSC XXX. #1332 [4] Bérczi Sz., Kabai S., Hegyi S., Cech V., Drommer B., Földi T., Fröhlich A., Gévay G. (1999): LPSC XXX, #1037; [5] S. Hegyi, B. Kovács, M. Keresztesi, I. Béres, Gimesi, Imrek, Lengyel, J. Herbert (2000): LPSC XXXI, #1103, Houston, [6] T. Diósy, F. Roskó, K. Gránicz, B. Drommer, S. Hegyi, J. Herbert, M. Keresztesi, B. Kovács, A. Fabriczy, Sz. Bérczi (2000): LPSC XXXI, #1153, Houston, [7] F. Roskó, T. Diósy, Sz. Bérczi, A. Fabriczy, V. Cech, S. Hegyi (2000): LPSC XXXI, #1572, Houston, [8] Balogh, Zs., Bordás, F., Bérczi, Sz., Diósy, T., Hegyi, S., Imrek, Gy., Kabai, S., Keresztesi, M. (2002): LPSC XXXIII, Abstract #1085, LPI, Houston (CD-ROM), [9] Hegyi, S., Horváth, Cs., Németh, I., Keresztesi, M., Hegyi, Á., Kovács, Zs., Diósy, T., Kabai, S., Bérczi, Sz. (2002): LPSC XXXIII, Abstract #1124, LPI, Houston (CD-ROM), [10] Sz. Bérczi, T. Diósy, Sz. Tóth, S. Hegyi, Gy. Imrek, Zs. Kovács, V. Cech, E. Müller-Bodó, F. Roskó, L. Szentpétery, Gy. Hudoba (2002): LPSC XXXIII, Abstract #1496, LPI, Houston (CD-ROM). 2

Berczi, Sz.; Hegyi, S.; Hudoba, Gy.; Hargitai, H.; Kokany, A.; Drommer, B.; Biro, T.; Gucsik, A.; Pinter, A.; Kovacs, Zs.

300

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

301

NASA - Liftoff to Learning: "Voyage of Endeavour - Then and Now"  

NASA Website

NASA.gov brings you images, videos and interactive features from the unique perspective of America's space agency. Get the latest updates on NASA missions, subscribe to blogs, RSS feeds and podcasts, watch NASA TV live, or simply read about our ...

302

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

303

The voyages of Apollo: The exploration of the moon  

Microsoft Academic Search

The scientific background of the exploration of the moon conducted in connection with the Apollo project is examined, giving attention to models of the moon and the general significance of lunar investigations for the study of the solar system. Space programs preceding the Apollo project and helping to prepare the technological and navigational basis for it are examined, taking into

R. S. Lewis

1974-01-01

304

Space 2000. Meeting the challenge of a new era.  

NASA Astrophysics Data System (ADS)

Contents: Part I: Voyaging into orbit and beyond. 1. Challenger. 2. NASA and its foreign competitors in the 1980s. 3. Highways to heaven.Part II: The practical uses of space. 4. Communications satellites. 5. The orbital high ground: weather watching, spying and star wars. 6. Earth science: a global view of a green planet. 7. Materials processing in space: making pie in the sky, or the next industrial revolution?Part III: Exploring thenear and distant universe. 8. The golden age of planetary exploration. 9. Earthlike planets and the magnet that is Mars. 10. Voyage to the land of the giants. 11. Exploration of the distant universe. 12. Intelligent life in the universe.Part IV: The future. 13. The human roles in space. 14. Permanent stations in space and on the Moon. 15. Space in the twenty-first century.

Shipman, H. L.

305

A voyage from dark clouds to the early Earth  

NASA Astrophysics Data System (ADS)

Stellar nucleosynthesis of heavy elements, followed by their subsequent release into the interstellar medium, enables the formation of stable carbon compounds in both gas and solid phases. Spectroscopic astronomical observations provide evidence that the same chemical pathways are widespread both in the Milky Way and in external galaxies. The physical and chemical conditions - including density, temperature, ultraviolet radiation and energetic particle flux - determine reaction pathways and the complexity of organic molecules in different space environments. Most of the organic carbon in space is in the form of poorly-defined macromolecular networks. Furthermore, it is also unknown how interstellar material evolves during the collapse of molecular clouds to form stars and planets. Meteorites provide important constraints for the formation of our Solar System and the origin of life. Organic carbon, though only a trace element in these extraterrestrial rock fragments, can be investigated in great detail with sensitive laboratory methods. Such studies have revealed that many molecules which are essential in terrestrial biochemistry are present in meteorites. To understand if those compounds necessarily had any implications for the origin of life on Earth is the objective of several current and future space missions. However, to address questions such as how simple organic molecules assembled into complex structures like membranes and cells, requires interdisciplinary collaborations involving various scientific disciplines.

Ehrenfreund, P.; Charnley, S. B.; Botta, O.

306

Comparison of initial cassini\\/lemms and voyager 1 and 2 low energy charged particle trapped radiation observations  

Microsoft Academic Search

Voyager 1 and 2 observations with the Low Energy Charged Particle instrument were used to optimize the design of the Cassini\\/MIMI\\/LEMMS instrument. Hence, initial studies of LEMMS observations during Jupiter approach and SOI will include reconciliation of the Cassini and Voyager fluxes and energy spectra of energetic electrons and ions from about 20 keV up to several MeV for electrons

T. Armstrong; J. Manweiler; N. Krupp; S. Livi; S. Krimigis; D. Mitchell; L. Lanzerotti

2004-01-01

307

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

308

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

309

Hybridity, Race, and Science: The Voyage of the Zaca, 1934–1935  

Microsoft Academic Search

In 1929 and 1934–1935, the physical anthropologist Harry L. Shapiro voyaged in the South Seas on the Mahina-I-Te-Pua and the Zaca, measuring mixed-race islanders, including the descendants of the Bounty mutineers on Pitcairn Island. His research in Polynesian hybridity reflects the growing cultural and scientific investment of the United States in the Pacific during this period. Shapiro's oceanic adventures and

Warwick Anderson

2012-01-01

310

New experimental results on GPS\\/INS navigation for Ocean Voyager II AUV  

Microsoft Academic Search

This paper presents preliminary experimental results on small-sized autonomous underwater vehicle navigation in shallow water environments. The vehicle was chosen to be our second-generation Ocean Voyager II which has been integrated with on-board GPS\\/INS sensors. These first-cut results reveal practical problems when using raw GPS fixes to perform high-precision real-time navigation. Among these, the most damaging factor is the observed

P. E. An; A. J. Healey; S. M. Smith; S. E. Dunn

1996-01-01

311

Origin and evolution of fluctuations in the solar wind: Helios observations and Helios-Voyager comparisons  

Microsoft Academic Search

Using hour-averaged data from the Helios and Voyager spacecraft, we have investigated the origin and evolution of low-frequency interplanetary fluctuations from 0.3 to 20 AU. Alfvenic fluctuations in the inner solar system are found to be generally outward traveling from the Sun and at times quite pure, in general agreement with previous work. The correlation between velocity and magnetic field

D. A. Roberts; M. L. Goldstein; L. W. Klein; W. H. Matthaeus

1987-01-01

312

Characteristic of hot plasma in the Jovian magnetosphere: Results from the Voyager spacecraft  

Microsoft Academic Search

The low-energy charged particle (LECP) experiment on the Voyager 1 and 2 spacecraft made measurements of the intensity, energy spectra, angular distributions and composition of ions (30 keV< or approx. =E< or approx. = 150 MeV) and the electrons (14 keV< or approx. =E< or approx. =10 MeV) during encounters with the Jovian magnetosphere in 1979. Detailed analysis of the

S. M. Krimigis; J. F. Carbary; E. P. Keath; C. O. Bostrom; W. I. Axford; G. Gloeckler; L.J. Lanzerotti; T. P. Armstrong

1981-01-01

313

A modified subreflector design and diffraction analysis of Voyager's high gain antenna for Cassini spacecraft  

Microsoft Academic Search

The Cassini mission requires that the reflector antenna be able to operate at four different frequencies. This means that in addition to the direct-fed S-band and Cassegrain-fed X-band operations, direct-fed Ku-band and Cassegrain-fed Ka-band operations are added on the Cassini antenna. A design scenario involving relatively simple and minor modifications to the existing Voyager dual-shaped symmetric antenna configuration is discussed.

V. Jamnejad; Y. Rahmat-Samii

1991-01-01

314

Multispectral and geomorphic studies of processed Voyager 2 images of Europa  

Microsoft Academic Search

High resolution images of Europa taken by the Voyager 2 spacecraft were used to study a portion of Europa's dark lineations and the major white line feature Agenor Linea. Initial image processing of images 1195J2-001 (violet filter), 1198J2-001 (blue filter), 1201J2-001 (orange filter), and 1204J2-001 (ultraviolet filter) was performed at the U.S.G.S. Branch of Astrogeology in Flagstaff, Arizona. Processing was

T. A. Meier

1984-01-01

315

Saturn's A Ring as Seen by the Voyager IRIS and Cassini CIRS Experiments  

NASA Astrophysics Data System (ADS)

During Cassini's successful orbital insertion manuever at Saturn its Composite Infrared Spectrometer (CIRS) obtained thermal spectra of Saturn's rings at a range of geometries not seen since the Voyager flybys. CIRS is a Fourier-transform spectrometer that measures infrared radiation from 7 microns out to 1 millimeter (1400 to 10 cm-1 ). Of the main rings, the A Ring was observed at the greatest range of phase and emission angles during Saturn orbit insertion. Scans of the lit and unlit sides of the A Ring were obtained at a spectral resolution of 15.5 cm-1 and at low ( ˜ 60o ) and intermediate ( ˜ 130o - 140o ) phase angles. The infrared interferometer spectrometer (IRIS) experiments aboard Voyagers 1 and 2 also obtained thermal spectra of the rings. IRIS, the predecessor of the CIRS instrument, is a Michelson interferometer that records spectra between 4 and 55.5 ? m (2500 to 180 cm-1 ). Spectra of the lit and unlit A Ring with a resolution of 4.3 cm-1 were obtained at phase angles somewhat lower than CIRS SOI scans ( ˜ 30o ) and at intermediate phase angles comparable to those observed by CIRS. We will interpret Cassini observations of the A Ring in the context of the earlier Voyager observations. A Ring brightness temperatures retrieved from the SOI scans clearly show a dependence on viewing geometry, varying by ˜ 10 K . The wide range of viewing geometries provided by the two sets of observations will allow us to determine the effect of viewing geometry on the ring's brightness temperature. By separating out such viewing geometry effects, we can constrain the physical properties of the ring as a whole as well as those of its constituent particles. Additionally, the time separation between the CIRS and IRIS observations will allow us to identify any changes in ring temperatures between the Voyager and Cassini epochs as might be expected from, for example, differences in solar elevation angle.

Brooks, S. M.; Spilker, L. J.; Pilorz, S. H.; Edgington, S. G.; Wallis, B. D.; Pearl, J. C.; Flasar, F. M.; Ferrari, C.; Showalter, M. R.; Achterberg, R. K.; Nixon, C. A.; Simon-Miller, A. A.; Romani, P. N.

2004-12-01

316

Albedo, internal heat, and energy balance of Jupiter - Preliminary results of the Voyager infrared investigation  

Microsoft Academic Search

Full disk measurements recorded by the 0.4-1.7 micron radiometer on Voyager 1 indicate a geometric albedo of 0.274 + or - 0.013. This measurement and the Pioneer-based phase integral of 1.25 yield a Jovian Bond albedo of 0.343 + or - 0.032. Infrared spectra yield a thermal emission of 1.359 + or - 0.014 x .001 W\\/sq cm, which corresponds

R. A. Hanel; B. J. Conrath; L. W. Herath; V. G. Kunde; J. A. Pirraglia

1981-01-01

317

Evaluation of the exposure of a merchant ship crew to mechanical vibration during a sea voyage.  

PubMed

Vibration levels were measured on a Roll-on/Roll-off type ship, during her voyage, with the use of Bruel and Kjaer equipment. The calculated equivalent values of mechanical vibration accelerations for various workplaces and for living quarters did not exceed the acceptable levels, according to Polish hygienic standards for border values of comfort of work. The intensity of vibration in selected places was generally determined by longitudinal vibration. The prevailing frequency was 8 Hz. PMID:2135912

Szczepa?ski, C

1990-01-01

318

Radio range measurements of coronal electron densities at 13 and 3. 6 centimeter wavelengths during the 1988 solar conjunction of Voyager 2  

SciTech Connect

Radio range measurements of total solar plasma delay obtained during the solar conjunction of the Voyager 2 spacecraft in December 1988, which occurred near solar maximum activity in the 11 yr cycle are reported. The radio range measurements were generated by the Deep Space Network at two wavelengths on the downlink from the spacecraft: 3.6 and 13 cm. A direct measurement of the integrated electron density along the ray path between the earth stations and the spacecraft was obtained by differencing the range at the two wavelengths. Coronal electron density profiles have been derived during ingress and egress of the ray path, which approached the sun to within 5 solar radii. At 10 solar radii, the derived density profiles yield 34079 {plus minus} 611/cu cm on ingress and 49688 {plus minus} 983/cu cm on egress. These density levels are significantly higher than observed near previous solar maxima. 19 refs.

Krisher, T.P.; Anderson, J.D.; Morabito, D.D.; Asmar, S.W.; Borutzki, S.E.; Delitsky, M.L.; Densmore, A.C.; Eshe, P.M.; Lewis, G.D.; Maurer, M.J. (JPL, Pasadena, CA (USA))

1991-07-01

319

Analysis of Clumps in Saturn’s F Ring from Voyager and Cassini Observations  

NASA Astrophysics Data System (ADS)

Saturn's F ring is well known for its unique and dynamic features that change on timescales from hours to months. Among these features are clumps, localized bright areas spanning ~3-30 degrees in longitude. 34 clumps tracked in Voyager images (Showalter 2004, Icarus, 171, 356-371) were found to live for several months and have a ~100 km spread in semi-major axis around the F ring core. Several clumps appeared to "split" during their lifetimes. Unfortunately, the poor resolution of the Voyager images and limited temporal and longitudinal coverage prevented a more detailed analysis. In this study, we performed a similar analysis using six years' worth of images from the Cassini Orbiter. We tracked 96 clumps and found similar angular widths, lifetimes, and semi-major axes to those observed by Voyager. However, the number of clumps present at one time appears to have decreased and the clumps are generally less bright; there are also many fewer extremely bright clumps. The better quality images allowed us to investigate five "splitting" clumps and we found that the apparent splits were often caused by the passage of the inner shepherd moon Prometheus. We further found that the birth and death of clumps appears uncorrelated with the position of Prometheus or with other features such as "mini-jets" or "jets" often found in the ring. We speculate on the changes in the population of embedded moonlets that may have resulted in these changes.

French, Robert S.; Hicks, S. K.; Showalter, M. R.; Antonsen, A. K.; Packard, D. R.

2013-10-01

320

On the latitudinal distribution of Titan's haze at the Voyager epoch  

NASA Astrophysics Data System (ADS)

In this work, we re-analyse a total of 10 high phase angle images of Titan (2 from Voyager 1 and 8 from Voyager 2). The images were acquired in different filters of the Voyager Imaging Sub System in 1980 - 1981. We apply a model, developed and used by Rannou etal. (1997) and Cabane etal. (1992), that calculates the vertical (1-D) distribution of haze particles and the I/F radial profiles as a function of a series of parameters. Two of these parameters, the haze particle production rate (P) and imaginary refractive index (xk), are used to obtain fits to the observed I/F profiles at different latitudes. Differerent from previous studies is that we consider all filters simultaneously, in an attempt to better fix the parameter values. We also include the filter response functions, not considered previously. The results show that P does not change significantly as a function of latitude, eventhough somewhat lower values are found at high northern latitudes. xk seems to increase towards southern latitudes. We will compare our results with GCM runs, that can give the haze distribution at the epoch of the observations. Work financed by portuguese Foundation for Science and Tecnology (FCT), contract ESO/PRO/40157/2000

Negrao, A.; Roos-Serote, M.; Rannou, P.; Rages, K.; McKay, C.

2002-09-01

321

Probes, Exploration and Application  

NSDL National Science Digital Library

This lesson examines some of the benefits of the space program to our life on Earth. The activities introduce students to what probes are, how they are designed, what they do, and how they provide information about surfaces without allowing us to actually see it (remote sensing).

322

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

323

Radio science with voyager 2 at saturn: atmosphere and ionosphere and the masses of mimas, tethys, and iapetus.  

PubMed

Voyager 2 radio occultation measurements of Saturn's atmosphere probed to the 1.2-bar pressure level, where the temperature was 143 +/- 6 K and the lapse rate apparently equaled the dry adiabatic value of 0.85 K per kilometer. The tropopause at both mid-latitude occultation locations (36.5 degrees N and 31 degrees S) was at a pressure level of about 70 millibars and a temperature of approximately 82 K. The stratospheric structures were very similar with the temperature rising to about 140 K at the 1-millibar pressure level. The peak electron concentrations sensed were 1.7 x 10(4) and 0.64 x 10(4) per cubic centimeter in the predawn (31 degrees S) and late afternoon (36.5 degrees N) locations. The topside plasma scale heights were about 1000 kilometers for the late afternoon profile, and 260 kilometers for the lower portions and 1100 kilometers for the upper portions of the topside predawn ionosphere. Radio measurements of the masses of Tethys and Iapetus yield (7.55 +/- 0.90) x 10(20) and (18.8 +/- 1.2) x 10(20) kilograms respectively; the Tethys-Mimas resonance theory then provides a derived mass for Afimas of (0.455 +/- 0.054) x 10(20) kilograms. These values for Tethys and Mimas represent major increases from previously accepted ground-based values, and appear to reverse a suggested trend of increasing satellite density with orbital radius in the Saturnian system. Current results suggest the opposite trend, in which the intermediate-sized satellites of Saturn may represent several classes of objects that differ with respect to the relative amounts of water, ammonia, and methane ices incorporated at different temperatures during formation. The anomalously low density of lapetus might then be explained as resulting from a large hydrocarbon content, and its unusually dark surface markings as another manifestation of this same material. PMID:17771277

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

1982-01-29

324

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

325

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. A prototype 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 numbs 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. [and others

1995-10-01

326

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

327

The Asymmetric Current Mirror Probe  

NASA Astrophysics Data System (ADS)

The difference in floating potential, between two closely spaced probe tips, is often used as a measure of the electric field in plasmas. This technique assumes a thermal Maxwellian distribution for plasma electrons and is unreliable in the presence of a fast non-Maxwellian electron tail. The influence of fast-tail electrons on floating potential measurements can be mitigated by using emissive probes or probes of unbalanced collection area. These probes have floating potentials that are closer to plasma potential than the floating potential of a standard Langmuir probe. An example of an unbalanced area probe is the ball-pen probe [Schrittwieser, et al., Rom. Journ. Phys., Vol. 50, 2005], in which the ion collection area is substantially larger than the electron collection area. The asymmetric current mirror probe achieves the effect of unbalanced collection area electronically, by amplification of the current drawn to the ion tip. Comparisons of radial profiles of floating potential in the LAPD at UCLA, measured using a Langmuir probe, ball-pen probe and asymmetric mirror probe are presented. The effects of using differences in floating potential, measured by these various probes, to determine the electric field is discussed.

Maggs, J. E.; Carter, T. A.

2008-11-01

328

John Lawson's "A New Voyage to Carolina": notes on the publication history of the London (1709) edition.  

PubMed

John Lawson's "A New Voyage to Carolina," an important source document for American colonial natural history, was first printed in 1709 in "A New Collection of Voyages and Travels," a two-volume set that also contained travel books translated by John Stevens. Lawson's publishers were leaders in the book trade of early eighteenth century London, and the "New Voyage" is typical of the resurgent popular interest in foreign travel narratives and exotic flora and fauna that began in the late 1600s. The "New Collection" was among the earliest examples of books published in serial instalments or fascicles, a marketing strategy adopted by London booksellers to broaden the audience and increase sales. Analysis of London issues of the "New Voyage" indicates that the 1709, 1711, 1714, and 1718 versions are simply bindings of the original, unsold sheets from the 1709 "New Collection" edition, differing only by new title-pages, front matter, and random stop-press corrections of type-set errors. Lawson's "New Voyage" illustrates important aspects of the British book trade during the hand press period of the early eighteenth century. PMID:19271343

Simpson, Marcus B; Simpson, Sallie W

2008-01-01

329

The Radiation Belt Storm Probes  

NASA Video Gallery

The Radiation Belt Storm Probe mission (RBSP) will explore the Van Allen Radiation Belts in the Earth's magnetosphere. The charge particles in these regions can be hazardous to both spacecraft and astronauts. The mission will explore space weather -- changes in Earth's space environment caused by the sun -- which can affect our technology.

gsfcvideo

2012-08-09

330

A Theorist's View of Recent Observations by Voyager 1 in the Outer Heliosphere  

NASA Astrophysics Data System (ADS)

Recent observations of energetic particles on the Voyager 1 spacecraft in the outer heliosphere suggest new phenomena associated with its approach to the termination shock of the solar wind. Interpretations of the data have lead to controversy, with some claiming that the termination shock has been crossed and others not. I will review the published data from the relevant Voyager1 instruments and discuss their interpretation. No completely satisfactory model or theory which explains the basic data consistently has been produced. The various theoretical ideas advanced to explain the phenomena will be discussed. If the energetic particle data are taken to imply that the termination shock has indeed been crossed (Krimigis, et al, Nature, 2003) then we must understand why no compression of the magnetic field was observed (Burlaga, et al, GRL, 2003). However, if the termination shock has not been crossed (McDonald, et al, Nature, 2003), then the observed power-law energy spectrum down to very low energies reported by Krimigis, et al, is difficult to explain. Similarly, the radio data (Gurnett, et al, GRL, 2003) show no evidence of a shock crossing. These issues have been discussed, but there is, as yet, no generally accepted explanation of these data. The observed streaming anisotropies of the energetic particles provide valuable constraints on the physics, and they have been interpreted to support both the idea that the shock has been crossed and that it hasn't. Published theoretical analyses of particle acceleration and transport upstream of a shock (Jokipii and Giacalone, Ap. J. Lett 2004; Jokipii etal., Ap. J. Lett., 2004) suggest that the observed anisotropies are most-readily interpreted if Voyager 1 was near the termination shock, but that the shock was not crossed.

Jokipii, J. R.

2004-12-01

331

3D modeling and turbulence: from the Sun to Voyager 1  

NASA Astrophysics Data System (ADS)

We compare in-situ observations at ACE and Ulysses with simulation results obtained from two different 3D models. Specifically, we look at results from the time dependent full 3D MHD HHMS model and also from the quick-look tool: the 3D HAFv2 kinematic model. These comparisons provide insights into the 3D propagation of interplanetary shocks. We find excellent agreement between results from our 3D models and spacecraft data. Our results also suggest that Voyager 1 and Voyager 2 continue to observe the effects of solar-induced shocks. The presence of planar magnetic structures is found from ACE to Voyager 1 in association with the Halloween 2003 events. These results are consistent with large-scale compressions and may have possible consequences for cosmic ray modulation. The results of our models, along with numerous in-situ observations, illustrate several aspects of interplanetary shock propagation that have implications for future modeling efforts. First, only continuous 3D models can accurately capture the dramatic asymmetries that often evolve over time. Second, although in-situ observations (at Earth, L1. etc.) are unquestionably valuable (e.g., for helping to refine or ``tune'' a model), because shock-induced effects may sometimes miss a location entirely, any model (1D, 2D, or even 3D) that relies only on such observations can often make seriously erroneous predictions. Third, along the same lines, any attempt to model the propagation of solar phenomena must begin this propagation at the source - the Sun. And, finally, because such propagation is going to be heavily dependent on the state of the medium through which it is propagating, models must incorporate this pre-event state. Thus, we emphasize the importance of using these primary solar source data as continuous inputs into models that extrapolate in three dimensions phenomena from the solar surface throughout the heliosphere and into the heliosheath.

Intriligator, Devrie S.; Rees, Adam; Horbury, Timothy; Sun, Wei; Detman, Thomas; Dryer, Murray; Deehr, Charles; Intriligator, James

2007-08-01

332

Evolution of the Anomalous Cosmic Ray Energy Spectra at Voyager 1 and 2 in the Heliosheath  

NASA Astrophysics Data System (ADS)

In December 2008 the Voyager 1 (V1) spacecraft will be at ~108 AU and 34 deg N. It is in the heliosheath, ~17 AU beyond the solar wind termination shock (TS) at that latitude. The Voyager 2 (V2) spacecraft will be at ~88 AU and 28 deg S. It also is in the heliosheath, having crossed the TS several times from 30 August to 1 September 2007 at 83.7 AU. The energy spectra of H, He, and O in the heliosheath show evidence of three separate components: a low-energy termination shock particle (TSP) component that likely originates locally at the TS and is convected to the spacecraft, a high-energy galactic cosmic ray (GCR) component, and a mid-energy anomalous cosmic ray (ACR) component whose source region and acceleration mechanism are the subject of differing models. Since ~mid-2005 the TSP component at Voyager 1 has been remarkably steady. Subtracting this component and the GCR component reveals evolving ACR spectra that appear to be unfolding towards source spectra as V1 moves deeper into the heliosheath. At V2 there has been significant evolution in the TSP energy spectra during its ~one year in the heliosheath. Recently, however, the TSP energy spectra resemble those at V1 and the ACR energy spectra have a heavily modulated shape resulting in an energy-dependent positive gradient between the two spacecraft. We will examine the ACR energy spectra at both V1 and V2 and compare with predictions of competing theoretical models for the origin and acceleration of ACRs. This work was supported by NASA under contract NAS7-03001.

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

2008-12-01

333

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

334

Voyager observations of anomalous and galactic cosmic rays in the heliosheath  

NASA Astrophysics Data System (ADS)

Both Voyager spacecraft are now in the heliosheath and observing at least three populations of energetic particles. At the highest energies, above ˜100 MeV/nuc for He, galactic cosmic rays (GCRs) dominate the energy spectrum. Both spacecraft are observing about the same intensity of this population, implying a lower than expected radial gradient in the heliosheath. From ˜10 to 100 MeV/nuc, the He energy spectrum is dominated by anomalous cosmic rays (ACRs). Neither spacecraft observed the expected shape of this spectrum from diffusive shock acceleration as it crossed the termination shock (TS), namely a power-law at low energies with a roll off at higher energies. At the present time, the energy spectrum of ACR He at Voyager 1 (V1) is unrolled to what could be the expected source shape, but the energy spectrum at Voyager 2 (V2) is still modulated. This could imply that there is a radial gradient of midenergy ACRs in the heliosheath, supporting theories that place the source of the ACRs back along the flanks or tail of the TS or theories that involve continuous acceleration across the heliosheath. Complicating the interpretation is a large temporal change in the energy spectra at both spacecraft that occurred during the 2.7 years between the V1 TS crossing in December 2004 and the V2 TS crossing in August 2007. At the lowest energies, a component is observed that is likely accelerated at the TS near to where the spacecraft crossed and which is convected to the spacecraft. At the meeting we will describe the latest observations of ACRs and GCRs in the heliosheath and discuss the implications for the source region and acceleration mechanism of ACRs and the energy spectrum of GCRs in the local interstellar medium. This work was supported by NASA under contract NAS7-03001.

Cummings, A. C.; Stone, Edward; McDonald, F. B.; Heikkila, B. C.; Lal, N.; Webber, Bill

335

Far ultraviolet reflection spectrum of Uranus - Results from the Voyager encounter  

SciTech Connect

The present analysis of the 1250-1700 A region Uranus spectrum obtained by Voyager's US spectrometer characterizes these observation results as due primarily to solar light reflected from an H2 Rayleigh and Raman scattering atmosphere with small but measurable hydrocarbon absorption. The hydrocarbon abundances obtained are substantially lower than those at comparable levels of the Saturn or Jupiter atmospheres; it is suggested, in one-dimensional terms, that this is due to diffusive separation, in conjunction with photochemical depletion caused by a very low eddy-diffusion coefficient. Strong latitudinal variations in the hydrocarbon abundances are suggested in the subsolar, polar stratosphere. 38 references.

Yelle, R.V.; Doose, L.R.; Mcconnell, J.C.; Strobel, D.F.

1989-02-01

336

Titan's atmosphere from Voyager infrared observations. I - The gas composition of Titan's equatorial region  

Microsoft Academic Search

After inferring minor atmospheric-constituent abundances in Titan's equatorial region from Voyager 1 IR spectra, a stratospheric temperature profile is derived. An analysis of three different sections has yielded stratospheric mole fractions for C2H2, C2H4, C2H6, C3H4, C3H8, C4H2, HCN, and CO2; an altitude-dependent CO2 profile has been tested against observations, but no conclusive data on vertical distribution could be extracted.

A. Coustenis; B. Bezard; D. Gautier

1989-01-01

337

Remote sensing of the magnetic moment of Uranus - Predictions for Voyager  

NASA Astrophysics Data System (ADS)

The current understanding of the power transfer mechanisms by which power is supplied to a planet's magnetosphere by the kinetic energy of planetary spin and the energy flux of the impinging solar wind is applied to the case of Uranus, in order to predict the detectability of radio and auroral emissions by the planetary radio astronomy (PRA) and UV spectrometer (UVS) instruments of the Voyager spacecraft. The power available for the two energy transfer phenomena cited is a function of Uranus' magnetic moment, which is presently derived for each power source as a function of the date of first detection of radio emissions by the PRA or auroral emissions by the UVS.

Hill, T. W.; Dessler, A. J.

1985-03-01

338

Characteristics of hot plasma in the Jovian magnetosphere - Results from the Voyager spacecraft  

NASA Astrophysics Data System (ADS)

Measurements of the intensities, energy spectra, angular variations, and composition characteristics of the low-energy ion populations (approximately 30 keV to 4 MeV) obtained by both Voyager spacecraft in the outer (more than about 10 Jupiter radii) Jovian magnetosphere are reported and interpreted. Also shown are some of the energetic electron measurements. Using the spectral and angular ion measurements, density and pressure profiles in the magnetosphere are constructed and then compared with results reported by the plasma wave and plasma science investigations (density) and the magnetic field investigation (pressure).

Krimigis, S. M.; Carbary, J. F.; Keath, E. P.; Bostrom, C. O.; Axford, W. I.; Gloeckler, G.; Lanzerotti, L. J.; Armstrong, T. P.

1981-09-01

339

Polarization response of the Voyager-PRA experiment at low frequencies  

NASA Astrophysics Data System (ADS)

An estimation is derived of the opening angle of the Planetary Radio Astronomy (PRA) low-frequency and antenna model from a set of four Voyager 1 and 2 pre- and postencounter Saturn kilometric radiation (SKR) observations. The effect of the opening angle on the polarization response of the PRA instrument is discussed. The relevant characteristics of SKR used to derive the opening angle are described. The influence of the intensity level of the observed radiation on the degree of circular polarization estimates is examined.

Ortega-Molina, A.; Lecacheux, A.

1990-03-01

340

Reusable science tools for analog exploration missions: xGDS Web Tools, VERVE, and Gigapan Voyage  

NASA Astrophysics Data System (ADS)

The Exploration Ground Data Systems (xGDS) project led by the Intelligent Robotics Group (IRG) at NASA Ames Research Center creates software tools to support multiple NASA-led planetary analog field experiments. The two primary tools that fall under the xGDS umbrella are the xGDS Web Tools (xGDS-WT) and Visual Environment for Remote Virtual Exploration (VERVE). IRG has also developed a hardware and software system that is closely integrated with our xGDS tools and is used in multiple field experiments called Gigapan Voyage. xGDS-WT, VERVE, and Gigapan Voyage are examples of IRG projects that improve the ratio of science return versus development effort by creating generic and reusable tools that leverage existing technologies in both hardware and software.xGDS Web Tools provides software for gathering and organizing mission data for science and engineering operations, including tools for planning traverses, monitoring autonomous or piloted vehicles, visualization, documentation, analysis, and search. VERVE provides high performance three dimensional (3D) user interfaces used by scientists, robot operators, and mission planners to visualize robot data in real time. Gigapan Voyage is a gigapixel image capturing and processing tool that improves situational awareness and scientific exploration in human and robotic analog missions. All of these technologies emphasize software reuse and leverage open source and/or commercial-off-the-shelf tools to greatly improve the utility and reduce the development and operational cost of future similar technologies.Over the past several years these technologies have been used in many NASA-led robotic field campaigns including the Desert Research and Technology Studies (DRATS), the Pavilion Lake Research Project (PLRP), the K10 Robotic Follow-Up tests, and most recently we have become involved in the NASA Extreme Environment Mission Operations (NEEMO) field experiments. A major objective of these joint robot and crew experiments is to improve NASAs understanding of how to most effectively execute and increase science return from exploration missions. This paper focuses on an integrated suite of xGDS software and compatible hardware tools: xGDS Web Tools, VERVE, and Gigapan Voyage, how they are used, and the design decisions that were made to allow them to be easily developed, integrated, tested, and reused by multiple NASA field experiments and robotic platforms.

Lee, Susan Y.; Lees, David; Cohen, Tamar; Allan, Mark; Deans, Matthew; Morse, Theodore; Park, Eric; Smith, Trey

2013-10-01

341

Significant Science from a Saturn Atmospheric Entry Probe Mission  

NASA Astrophysics Data System (ADS)

A single planet cannot be understood in isolation. Comparative studies of gas and ice giant planets' atmospheres are needed to understand the origin and evolution of the solar system and the giant planets, formation of giant planet atmospheres, and to provide a valuable link to extrasolar planets. Giant planets' tropospheres and interiors contain material from the epoch of solar system formation. Some of these materials are expected to be unprocessed and thus would reflect the protosolar nebula's composition at the time and location of each planet's formation. Other materials will have been extensively processed, reflecting a planet's evolutionary processes. Beginning with the Pioneer and Voyager flybys, space flight missions began assembling data sets needed for these comparisons. The Galileo orbiter and probe mission provided both remote sensing and the first in situ studies of Jupiter's atmosphere. Comparable understanding of Saturn, Uranus and Neptune would provide an important comparative planetology context for the Galileo Jupiter results. The Cassini orbiter continues to yield a wealth of discoveries about Saturn's atmosphere from its remote sensing measurements, and its "Proximal Orbits" (2016 and 2017) will provide knowledge of Saturn's internal structure to complement the Juno mission's measurements at Jupiter. A Saturn entry probe mission, to complement the Galileo Probe investigations at Jupiter, would complete a solid basis for improved understanding of both Jupiter and Saturn, and an important stepping stone to understanding Uranus and Neptune, and the formation and evolution of the solar system. The draft "2012 Planetary Science Decadal Survey" (PSDS), released in March 2011, supports the high priority of a Saturn entry probe mission, recommending its addition to NASA's New Frontiers Program. It lists two levels of science objectives: Tier 1, highest-priority objectives that any New Frontiers implementation must achieve; and Tier 2, high priorities but somewhat lower than the Tier 1 objectives. Tier 1 focuses on Saturn's composition, with specific measurements to be described in the presentation, and thermal structure. Tier 2 objectives will also be listed in the presentation, along with payload options for the Tier 1 objectives. Leveraging the Cassini-Huygens mission's successful international collaborations, Tier 2 science objectives offer opportunities for significant enhancement of a Saturn probe mission's science return, and opportunities for international collaboration. To enhance the competitiveness of a NASA New Frontiers mission concept a prospective Principal Investigator could use Tier 2 objectives to customize the mission for the proper balance of science return, science team composition, resource needs, and procured or contributed instruments. Contributed instruments could be a significant factor in such a mission, since they can result in a more capable payload and a larger science team with broader expertise, and thus significantly enhanced science return. This paper will discuss the PSDS recommendations regarding a Saturn probe mission for NASA's New Frontiers program, and planetary and solar system science to be achieved.

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

2011-12-01

342

Space-Based Photometry of Eclipsing Binaries  

NASA Astrophysics Data System (ADS)

I briefly review the history and prospects for the study of eclipsing binary star systems from space-based observatories. The benefits of shifting to space satellites lie in the high precision and cadence achievable, as well as the ability to access wavelength regions which are unattainable from the ground. Whilst small amounts of data on eclipsing binaries were obtained by the Voyager, IUE, OAO-II, Hipparcos and MOST, the more recent CoRoT and Kepler missions were the first to provide extensive data on large numbers of systems. The future holds the prospect of the PLATO satellite, which will go bigger, better and brighter.

Southworth, John

2012-04-01

343

Indentation of a Punch with Chemical or Heat Distribution at Its Base into Transversely Isotropic Half-Space: Application to Local Thermal and Electrochemical Probes  

SciTech Connect

The exact solution to the coupled problem of indentation of the punch, subjected to either heat or chemical substance distribution at its base, into three-dimensional semi-infinite transversely isotropic material is presented. The entire set of field components are derived in terms of integrals of elementary functions using methods of the potential theory and recently obtained, by the authors, results for the general solution of the field equations in terms of four harmonic potential functions. The exact solution for the stiffness relations that relate applied force, total chemical diffusion/heat flux in the domain of the contact, with indenter displacement, temperature, or chemical substance distribution of diffusing species at the base, and materials' chemo/thermo-elastic properties are obtained in closed form and in terms of elementary functions. These results can be used to understand the image formation mechanisms in techniques such as thermal scanning probe microscopy and electrochemical strain microscopy

Karapetian, E. [Suffolk University, Boston; Kalinin, Sergei V [ORNL

2013-01-01

344

Energetic ion and electron phase space densities in the magnetosphere of Uranus  

Microsoft Academic Search

Voyager 2 low-energy charged particle (LECP) data from the magnetosphere of Uranus have been analyzed to obtain proton and electron phase space density profiles. The Uranus proton profiles show an approximately exponential decline with decreasing radius for L ⪅ 9 in a relatively dense thermal plasma region with intense plasma wave activity. An analogy with the magnetospheres of Earth, Jupiter,

Andrew F. Cheng; S. M. Krimigis; B. H. Mauk; E. P. Keath; C. G. Maclennan

1987-01-01

345

News and Views: Transit events and resources; HST to use transit to probe venusian atmosphere; Now, the space weather forecast; Astronomy writing prize  

NASA Astrophysics Data System (ADS)

TRANSIT Early risers in the UK have the opportunity to see the final stages of the last transit of Venus for more than a century. TRANSIT Researchers interested in the atmosphere of Venus will be using the Hubble Space Telescope and the Moon to examine sunlight passing through the atmosphere during the transit of Venus this month. The technique is the same as that used to determine atmospheric constituents of transiting exoplanets. The Met Office is expanding its services to include operational space-weather forecasts for the UK, working with the research community to expand existing climate models. Further collaborative work will apply the enhanced model to extrasolar planets. The ESO and the STFC are organizing a Europe-wide competition for the very best in astronomy journalism in print, online or broadcast. The winner gets a trip to ESO's Very Large Telescope in Chile.

2012-06-01

346

Certain Forms of Matrix Metalloproteinase-9 Accumulate in the Extracellular Space After Microdialysis Probe Implantation and Middle Cerebral Artery Occlusion\\/Reperfusion  

Microsoft Academic Search

Matrix metalloproteinases (MMPs) are activated in focal cerebral ischemia. The activation of MMP-9 is involved in blood–brain barrier breakdown and tissue remodeling. The MMPs are released to the extracellular space, but the form and fate of secreted enzymes in brain are unknown. Using microdialysis in vivo, the authors studied whether ischemia-induced MMP-9 in brain tissue was related to free MMP-9

Anna M. Planas; Carles Justicia; Sňnia Solé; Bibiana Friguls; Álvaro Cervera; Albert Adell; Ángel Chamorro

2002-01-01

347

Satellite control of Jovian 2-6 MHz radio emission using Voyager data  

NASA Astrophysics Data System (ADS)

Jupiter's satellite Io no longer has the only known effect in controlling the low-frequency Jovian radio emissions. Menietti et al. (1998, 2001) used a long and contiguous set of data in the range of 2.0-5.6 MHz from the Galileo spacecraft and found correlations with the orbital phase of Ganymede and Callisto. Recently, Higgins et al. (2006) used all of the Galileo orbiter data and found that Europa's phase shows a minor but statistically significant effect on the lower range of decametric emissions. In this paper, results are found that confirm previous work for all four Galilean satellites by combining Voyager 1 and Voyager 2 flyby data in the frequency range of 2.1-5.8 MHz. The data were analyzed using the unique occurrence probability data compilation technique that includes 10-hour averaging and satellite bias removal. A statistical significance Z-test was computed to compare sample populations for each enhanced region of occurrence against the background. We find significance values greater than the 95% confidence level (Z > 2?) for Io, Europa, Ganymede, and Callisto. Least squares fits to histograms of relative occurrence probability also show similar results. The cause of these correlations is believed to be Alfvénic interactions between the individual satellite and Jupiter.

Higgins, C. A.

2007-05-01

348

Far-ultraviolet mapping of the Cygnus Loop with the Voyager 2 Ultraviolet Spectrometer  

SciTech Connect

FUV maps of the Cygnus Loop made using spectroscopic data from the Voyager 2 Ultraviolet Spectrometer are presented. Emission line features at about 980 and about 1035 A dominate the 500-1700 A spectra of the Cygnus Loop as observed with Voyager. Maps were generated in the light of these two features. The 980 and 1035 A maps are compared with X-ray and optical images of the Cygnus Loop that have been sampled in the same manner. From this comparison it is clear that the 980 A feature arises mainly from regions of bright optical emission, whereas the 1035 A emission more closely resembles the X-ray emission. This general impression can be confirmed by inspection of the spectra as a function of position. Spectra extracted from positions corresponding to the primary shock front show the 1035 A feature to be relatively strong, while the 980 A feature is brighter when substantial optical emission is present within the aperture. 42 refs.

Blair, W.P.; Long, K.S.; Vancura, O.; Holberg, J.B. (Johns Hopkins University, Baltimore, MD (USA) Arizona, University, Tucson (USA))

1991-06-01

349

Ambient ion distributions in Saturn's magnetosphere near Titan during a non-Voyager type interaction  

NASA Astrophysics Data System (ADS)

The interaction of Titan's ionosphere with the Saturn's magnetospheric plasma was found to be subsonic, superAlfvénic and submagnetosonic. However, the plasma conditions along Titan's orbit are highly variable [cf. J. Geophys. Res., 87 (1982) 881; Ph.D Dissertation, University of Michigan, Ann Arbor, 2001] resulting in a wide range of possible Mach numbers for the interaction. We consider the effect Titan would have on the ambient (or magnetospheric) ion population during a supermagnetosonic interaction, which might occur in the outer magnetosphere. The trajectories of several thousand ions in the vicinity of Titan are calculated using the fields from the output of a three-dimensional MHD model of Titan's plasma interaction. We have simulated the Voyager Plasma Spectrometer (PLS) response to the ambient ions using the determined ion trajectories. These results are compared with the Voyager distribution functions in order to illustrate how upstream conditions might affect the observed distributions, as will likely be observed during the Cassini mission Titan flybys.

Ledvina, S. A.; Luhmann, J. G.; Cravens, T. E.

350

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

NASA Astrophysics Data System (ADS)

Because of a lack of readily usable information pertaining to the polarization of the Voyager 1 and 2 high-frequency band data, a technique has been developed that aids the identification of Io-dependent decametric radiation originating from the southern hemisphere of Jupiter. This technique compares the results of model ray tracing calculations with the Planetary Radio Astronomy (PRA) observations. A large portion of the Voyager 1 and 2 PRA observations are sorted into bins (ą3° wide) centered on a specific Io central meridian longitude. When the data are plotted (as a frequency-longitude spectrogram) in this coordinate system, Io-dependent features can be identified and compared with ray tracing calculations performed in a model Jovian magnetosphere where it is assumed that the decametric emissions are generated in the RX mode from low-altitude source regions along the instantaneous Io flux tube. Two different magnetic field models are used, and the results are contrasted. In this study, the authors compare the observations for constant sub-Io longitudes of 260° and 300° with the corresponding model ray tracings.

Menietti, J. D.; Green, J. L.; Six, N. F.; Gulkis, S.

1987-01-01

351

Seemingly Incongruous Voyager 1 & 2 Energetic Particle Observations in the Heliosheath Through 2011  

NASA Astrophysics Data System (ADS)

Conditions are changing in the heliosheath at the positions of Voyager 1 (V1) and Voyager 2 (V2) and are doing so in unexpected ways that so far defy a single consistent interpretation. Some characteristic intensity variations cut across a surprisingly broad range of energies and species, from termination shock particles (TSPs), to energetic electrons, to light and heavy anomalous cosmic rays (ACRs), and to galactic cosmic rays (GCRs). The changes must be a mix of spatial structure and temporal changes produced by the rise in activity of Solar Cycle 24 in January 2010. Yet there are drastic differences between some of the same species at V1 compared with V2. The puzzling observations include V1 ACR intensities beginning to decline while at V2 they are exponentially increasing, finally reaching levels comparable to or even exceeding those at V1. A distinct pattern of increases and decreases is seen at V2 in TSPs, electrons, light ACRs, and GCRs, but not in ACR heavy ions. However some things are happening similarly at V1 and V2, like a recent increase in GCR protons. We will present an overview of these observations, which also include spectral properties, anisotropies, and solar wind speed. An essential interpretive element is possible differences in the heliosheath configuration, in particular the location of the sector region between V1 and V2 and the proximity to the heliopause.

Hill, M. E.; Decker, R. B.; Drake, J. F.; Hamilton, D. C.; Krimigis, S. M.; Opher, M.; Roelof, E. C.

2011-12-01

352

A new look at the saturn system: the voyager 2 images.  

PubMed

Voyager 2 photography has complemented that of Voyager I in revealing many additional characteristics of Saturn and its satellites and rings. Saturn's atmosphere contains persistent oval cloud features reminiscent of features on Jupiter. Smaller irregular features track out a pattern of zonal winds that is symmetric about Saturn's equator and appears to extend to great depth. Winds are predominantly eastward and reach 500 meters per second at the equator. Titan has several haze layers with significantly varying optical properties and a northern polar "collar" that is dark at short wavelengths. Several satellites have been photographed at substantially improved resolution. Enceladus' surface ranges from old, densely cratered terrain to relatively young, uncratered plains crossed by grooves and faults. Tethys has a crater 400 kilometers in diameter whose floor has domed to match Tethys' surface curvature and a deep trench that extends at least 270 degrees around Tethys' circumference. Hyperion is cratered and irregular in shape. Iapetus' bright, trailing hemisphere includes several dark-floored craters, and Phoebe has a very low albedo and rotates in the direction opposite to that of its orbital revolution with a period of 9 hours. Within Saturn's rings, the "birth" of a spoke has been observed, and surprising azimuthal and time variability is found in the ringlet structure of the outer B ring. These observations lead to speculations about Saturn's internal structure and about the collisional and thermal history of the rings and satellites. PMID:17771273

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

1982-01-29

353

Detection of dust impacts by the Voyager planetary radio astronomy experiment  

NASA Astrophysics Data System (ADS)

The Planetary Radio Astronomy (PRA) instrument detected large numbers of dust particles during the Voyager 2 encounter with Neptune. The signatures of these impacts are analyzed in some detail. The major conclusions are described. PRA detects impacts from all over the spacecraft body, not just the PRA antennas. The signatures of individual impacts last substantially longer than was expected from complementary Plasma Wave Subsystem (PWS) data acquired by another Voyager experiment. The signatures of individual impacts demonstrate very rapid fluctuations in signal strength, so fast that the data are limited by the speed of response of the instrument. The PRA detects events at a rate consistently lower than does the Plasma Wave subsystem. Even so, the impact rate is so great near the inbound crossing of the ring plane that no reliable estimate of impact rate can be made for this period. The data are consistent with the presence of electrons accelerated by ions within an expanding plasma cloud from the point of impact. An ancillary conclusion is that the anomalous appearance of data acquired at 900 kHz appears to be due to an error in processing the PRA data prior to their delivery rather than due to overload of the PRA instrument.

Evans, David R.

1993-07-01

354

Constraints on Saturn's G Ring from the Voyager 2 Radio Astronomy Instrument  

NASA Astrophysics Data System (ADS)

We have reanalyzed the data acquired by the planetary radio astronomy (PRA) experiment during the passage of Voyager 2 through the outer part of Saturn's G ring, originally published by Aubier et al.(1983. Geophys. Res. Lett.10, 5-8). This study closely parallels the reanalysis of the Voyager 1 PRA data during the E-ring passage (Meyer-Vernet et al.1996. Icarus123, 113-128). The instrument detected dust grain impacts on the spacecraft in a region of ?1000 km vertical extent around the ring plane with a maximum at ring plane crossing. The signal is mainly produced by grains of radius of a few micrometers. We find a size distribution less steep than the r-6law inferred for submicrometer grains by Showalter and Cuzzi (1993. Icarus103, 124-143) from photometric data. These results can be reconciled if the slope of the size distribution flattens above 0.5 ?. Assuming a rough continuity between the distributions deduced from the two data sets and an r- qlaw for the grains detected by PRA, we infer that the differential power law index q< 3.5 for grain radii between about a half micrometer and a few micrometers. From the observed vertical profile, we deduce an effective ring vertical thickness H? 1200/( q- 1) km. When qvaries in the range 3.5-2, Hvaries in the range 500-1200 km and the geometric cross section per unit area is a few times 10 -6.

Meyer-Vernet, Nicole; Lecacheux, Alain; Pedersen, Bent M.

1998-04-01

355

Titan's Atmosphere From Recent Space And Earth Observations : Last Call Before Cassini/Huygens  

NASA Astrophysics Data System (ADS)

I will review our current knowledge of Titan's atmosphere in terms of composition and temperature structure based on spectra and images taken from the space and from the ground. The spectroscopic measurements cover mainly the mid-IR range (mainly from 5 to 100 micron) and were acquired from space missions and observatories such as the Voyager spacecraft and the Infrared Space Observatory (ISO). They pertain to stratospheric altitude levels. In spectro-imaging, we have data from the CFHT and the VLT in the near-infrared region, allowing us to probe further down in the atmosphere of Titan and all the way to the surface. I will discuss the analyses of the spectra and the current picture of the chemical composition (mainly focusing on gases and condensates) and vertical thermal structure that Titan presents. I will also show what capabilities has the Cassini-Huygens mission (and in particular CIRS) to bring new insights to our knowledge of Titan's atmospheric structure. References: Coustenis, A., B. Bézard 1995. Titan's Atmosphere from Voyager Infrared Observations: IV. Latitudinal Variations in Temperature and Composition. Icarus 115, pp. 126-140. Coustenis, A. et al. 1995. Titan's surface: composition and variability from the near-infrared albedo. Icarus 118, pp. 87-104. Combes, M., et al. 1997. Spatially resolved images of Titan by means of adaptive optics. Icarus 129, pp. 482-497. Coustenis, A., et al.1998. Evidence for water vapor in Titan's atmosphere from ISO/SWS data. Astron. Astrophys. 336, L85-L89. Coustenis, A., et al. 2001. Images of Titan at 1.3 and 1.6 microns with adaptive optics at the CFHT. Icarus 154, 501-515. Coustenis, A., et al. 2003. Titan's atmosphere from ISO mid-infrared spectroscopy. Icarus, 161, 383-403. Gendron, E., et al. 2003. VLT/NACO adaptive optics imaging of Titan. Astron. Astroph., in press. Lellouch, E., et al. 2003. Titan's 5-micron window: observations with the very large telescope. Icarus 162, 125-142. Lellouch, E. et al. 2004. Titan's 5 micron lightcurve. Icarus, in press.

Coustenis, A.

356

Probing the GC-LMXB Connection in NGC 1399: A Wide-field Study with the Hubble Space Telescope and Chandra  

NASA Astrophysics Data System (ADS)

We present a wide-field study of the globular cluster (GC)/low-mass X-ray binary (LMXB) connection in the giant elliptical NGC 1399. The large field of view of the Advanced Camera for Surveys/WFC, combined with Hubble Space Telescope and Chandra high resolution, allow us to constrain the LMXB formation scenarios in elliptical galaxies. We confirm that NGC 1399 has the highest LMXB fraction in GCs of all nearby elliptical galaxies studied so far, even though the exact value depends on galactocentric distance due to the interplay of a differential GC versus galaxy light distribution and the GC color dependence. In fact, LMXBs are preferentially hosted by bright, red GCs out to >5 R eff of the galaxy light. The finding that GCs hosting LMXBs follow the radial distribution of their parent GC population argues against the hypothesis that the external dynamical influence of the galaxy affects the LMXB formation in GCs. On the other hand, field-LMXBs closely match the host galaxy light, thus indicating that they are originally formed in situ and not inside GCs. We measure GC structural parameters, finding that the LMXB formation likelihood is influenced independently by mass, metallicity, and GC structural parameters. In particular, the GC central density plays a major role in predicting which GCs host accreting binaries. Finally, our analysis shows that LMXBs in GCs are marginally brighter than those in the field, and in particular the only color-confirmed GC with LX > 1039 erg s-1 shows no variability, which may indicate a superposition of multiple LMXBs in these systems. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

Paolillo, Maurizio; Puzia, Thomas H.; Goudfrooij, Paul; Zepf, Stephen E.; Maccarone, Thomas J.; Kundu, Arunav; Fabbiano, Giuseppina; Angelini, Lorella

2011-08-01

357

High resolution SNOM probes  

NASA Astrophysics Data System (ADS)

Development of nanotechnologies demands optical characterization and measurement techniques that yield information with resolutions well below the diffraction limit. This requires an increase of the resolution of scanning near-field optical microscopes (SNOMs) from 50-70 nm commercially available nowadays in the visible range, to beneficial 30 nm, where ? is the wavelength of light in free space. High resolution SNOM probes would be crucial in measurements of point spread functions of superlenses based on negative refraction and characterization of plasmonic circuitry. The resolution of SNOMs is ?r = d + 2a, where d is the diameter of a radiating aperture of a tapered-fiber metal-coated probe and a is a skin depth, that is the distance the electromagnetic field penetrates the metal coating. The size of the radiated field does not exceed the diameter ?r when the aperture-sample distance h is kept constant by the shear-force tuning fork method. One of the resolution parameters, the skin depth a, depends on the metal that coats the dielectric probe and the shape of the metal rim. For Ag and Al, the values of a are on the level of 10nm, when measured on a flat metal surface illuminated with a plane wave. Thus, the other resolution parameter which we intend to decrease is a probe diameter d. The probe should radiate enough energy to be detected in a reasonable scanning measurement time. Recently, we proved that probe emission depends on the charge density induced on the probe rim. To increase this density we propose enhancement of the photon-plasmon coupling on the interface between the dielectric core and the metal coating. To this end we corrugate the interface. In this paper we analyze the role of parameters of the corrugations and report on attempts to fabricate them.

Antosiewicz, Tomasz J.; Wróbel, Piotr; Szoplik, Tomasz

2008-12-01

358

Vector Voyage!  

NSDL National Science Digital Library

In this activity, students will use vector analysis to understand the concept of dead reckoning. Students will use vectors to plot their course based on a time and speed. They will then correct the positions with vectors representing winds and currents.

Integrated Teaching And Learning Program

359

Voyager: Reading and Writing for Today's Adults. Levels 4, 5 and 6 Teacher's Resource Guide [and] Student Book [and] Student Workbook [and] Puzzles [and] Vocabulary Workbook. Voyager Placement Tool for Levels Foundation-6 Student Booklet [and] Teacher Scoring Guide.  

ERIC Educational Resources Information Center

|This document contains the 15 publications constituting the third stage of the Voyager program, which is a four-stage program that utilizes contemporary content and instructional approaches to teach the reading, writing, critical thinking, and communication skills that adults need in today's world and to take adult learners from the beginning…

1999

360

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

361

A Nearby Galaxy in the Deep-Ultraviolet: Voyager 2 Observations of M33 from Lyalpha to the Lyman Limit  

Microsoft Academic Search

Observations of high-redshift galaxies in the emitted-wavelength regime around Lyalpha have renewed interest in the appearance of normal galaxies in the deep ultraviolet. This paper presents an analysis of spectrophotometry of the local Sc galaxy Messier 33 (NGC 598) obtained by Voyager 2, covering the range from below the Lyman limit to about 1250 Ĺ. The scanning nature of the

William C. Keel

1998-01-01

362

An analysis of the Voyager 2 ultraviolet spectrometer occultation data at Uranus and Triton: Inferring heat sources and model atmospheres  

Microsoft Academic Search

In January 1986, the Voyager 2 Ultraviolet Spectrometer (UVS) observed a stellar entrance and exit occultation and a solar occultation by Uranus. Temperatures inferred near the top of the atmosphere of Uranus from these occultations are much higher (872 K) than could be explained by solar extreme ultraviolet heating alone. One purpose of this thesis is to analyze the UVS

Michael Hugh Stevens

1992-01-01

363

A study of health effects of long-distance ocean voyages on seamen using a data classification approach  

PubMed Central

Background Long-distance ocean voyages may have substantial impacts on seamen's health, possibly causing malnutrition and other illness. Measures can possibly be taken to prevent such problems from happening through preparing special diet and making special precautions prior or during the sailing if a detailed understanding can be gained about what specific health effects such voyages may have on the seamen. Methods We present a computational study on 200 seamen using 41 chemistry indicators measured on their blood samples collected before and after the sailing. Our computational study is done using a data classification approach with a support vector machine-based classifier in conjunction with feature selections using a recursive feature elimination procedure. Results Our analysis results suggest that among the 41 blood chemistry measures, nine are most likely to be affected during the sailing, which provide important clues about the specific effects of ocean voyage on seamen's health. Conclusions The identification of the nine blood chemistry measures provides important clues about the effects of long-distance voyage on seamen's health. These findings will prove to be useful to guide in improving the living and working environment, as well as food preparation on ships.

2010-01-01

364

ChemVoyage: A Web-Based, Simulated Learning Environment with Scaffolding and Linking Visualization to Conceptualization  

ERIC Educational Resources Information Center

|The Web is now a standard tool for information access and dissemination in higher education. The prospect of Web-based, simulated learning platforms and technologies, however, remains underexplored. We have developed a Web-based tutorial program (ChemVoyage) for a third-year organic chemistry class on the topic of pericyclic reactions to…

McRae, Christopher; Karuso, Peter; Liu, Fei

2012-01-01

365

Intraoperative probes and imaging probes  

Microsoft Academic Search

.   Intraoperative probes have been employed to assist in the detection and removal of tumors for more than 50 years. For a period\\u000a of about 40 years, essentially every detector type that could be miniaturized had been tested or at least suggested for use\\u000a as an intraoperative probe. These detectors included basic Geiger-Müller (GM) tubes, scintillation detectors, and even state-of-the-art

Edward J. Hoffman; Martin P. Tornai; Martin Janecek; Bradley E. Patt; Jan S. Iwanczyk

1999-01-01

366

The role of nuclear reactors in space exploration and development  

Microsoft Academic Search

The United States has launched more than 20 radioisotopic thermoelectric generators (RTGs) into space over the past 30 yr but has launched only one nuclear reactor, and that was in 1965. Russia has launched more than 30 reactors. The RTGs use the heat of alpha decay of ²³⁸Pu for power and typically generate <1 kW of electricity. Apollo, Pioneer, Voyager,

Lipinski

2000-01-01

367

Shock-associated low-energy ion enhancements observed by Voyagers 1 and 2  

SciTech Connect

Observations of shock-associated > or =30 keV ion enhancements are presented using data from the Low Energy Charged Particle (LECP) experiment on Voyagers 1 and 2, launched on days 248 and 232, 1977, respectively. The observations include examples of energetic storm particle (ESP) events associated with flare-produced shocks and examples of corotating particle events (CPE) associated with forward and reverse shocks that bound corotating interaction regions in the outer heliosphere. The first well-defined CPE are not seen at Voyagers 1 and 2 until late 1978 when each spacecraft was at a heliocentric radial distance of approx.4 AU. Thus far, seven CPE have been identified in the Voyager 1 LECP data from launch through day 170, 1979. Most of these CPE show features similar to many of those observed at Pioneers 10 and 11, e.g., they have recurrent double-packed intensity enhancements showing little or no velocity dispersion at peak intensities, time durations of several days, soft (..gamma..> or approx. =4 for protons approx.1 MeV) energy spectra extending up to approx.5 MeV/nucleon and p/..cap alpha.. ratios that are lowest at the reverse peaks. The new LECP measurements also show for the first time that the CPE ion spectra extend, with no sign of a low-energy turnover, to energies as low as 30 keV/ion. If the CPE are produced by shock acceleration of an ambient particle source, the fact that the observed CPE exhibit well-formed high intensity peaks at 30 keV/ion means that the pre-acceleration energy of the source particle was <30 keV/ion. In several of the shock events, the lowest energy ion enhancements are confined mainly downstream of the CIR shocks, with the magnitude and duration of the upstream enhancements increasing with increasing ion energy. The similarities in the low energy ion morphologies observed near the shock during an ESP event and a CPE suggest that the same shock acceleration mechanism and propagation processes were operative in each case.

Decker, R.B.; Pesses, M.E.; Krimigis, S.M.

1981-09-30

368

Huygens probe on target  

NASA Astrophysics Data System (ADS)

In October 1997, a Titan/Centaur rocket lifting-off from Cape Canaveral will boost the spacecraft into a 6.7 year trajectory to reach Saturn. The trajectory will use two swing-bys of Venus in April 1998 and June 1999, followed by an Earth swing-by in August 1999 and a Jupiter swing-by in December 2000 to boost speed and reach Saturn in July 2004. A few months after going into orbit around Saturn, the Cassini spacecraft will release the Huygens probe for its descent through the atmosphere of Titan, the largest satellite of Saturn. The Huygens probe will measure the abundance of elements and compounds in Titan's atmosphere, the distribution of trace gases and aerosols, winds, temperature, pressure and surface state and its composition. A multi-spectral camera on the probe will provide images of the landscape of Titan. Titan is a unique planetary body in the solar system. It has an atmosphere which is primarily nitrogen. but is also rich in hydrocarbons. Due to the vast distance of the Saturnian system from the Sun, this atmosphere is at a very low temperature, thus greatly slowing down all the chemical processes. A study of this atmosphere will throw light on the development of our own atmosphere and contribute to our understanding of the origins of life on Earth. The Huygens probe is being developed by ESA with Aerospatiale (F) as the industrial prime contractor. Since the start of the programme in April 1990, very good progress has been made in design and hardware development. The entry into the Titan atmosphere will result in a very high surface temperature on the probe, generated as it decelerates due to the friction of the upper atmospheric layers. After the probe has slowed down sufficiently, a system of parachutes ensures a slow descent to the surface of Titan in approximately two and a half hours. The scientific measurements can only begin after the heat shield, which is needed to protect the probe during the high temperature entry phase, has been ejected. This occurs at an altitude of around 170 km above Titan's surface. In order to validate this complex sequence, a Balloon Drop Test was recently carried out on a full size model of the probe. The balloon carried the probe to an altitude of 36 km above the test range (ESRANGE) near Kiruna in Sweden. The probe was automatically released and all the descent control systems were operated. This test was completely successfully and the Descent Module was recovered on ground intact and functioning (pictures are available upon request). In addition, all the environmental testing has been carried out on another model to prove the structural and thermal integrity of the probe. The Structure Thermal and Pyro Model (SIAM) of the Huygens probe was delivered to NASA's Jet Propulsion Laboratory (JPL) on 5 th July, 1995 for combined testing with the Cassini spacecraft. For the electrical systems, a special Engineering Model has been subjected to functional testing and the results to date are successful. This model will also be delivered to JPL for combined testing in the near future. Currently-, the Flight Model hardware is being delivered to Daimler Benz in Munich, by the industrial subcontractors, where integration of the Flight Probe will take place. "The design and the production of this complex system in a relatively short time of four years has proceeded very smoothly thanks to the motivation of the European space industry", said Huygens ESA Project Manager Hamid Hassan. The Flight Probe will be delivered to NASA/JPL in early 1997 for a launch of Cassini-Huygens on a Titan IV/Centaur rocket in October 1997.

1995-07-01

369

Survey of low energy plasma electrons in Saturn's magnetosphere: Voyagers 1 and 2  

SciTech Connect

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 (suprathermal) non-Maxwellian component. A large scale positive radial gradient in electron temperature is observed, increasing from less than 1 eV in the inner magnetosphere to as high as 800 eV in the outer magnetosphere. Three fundamentally different plasma regimes were identified from the measurements: (1) the hot outer magnetosphere, (2) the extended plasma sheet, and (3) the inner plasma torus.

Sittler, E.C. Jr.; Ogilvie, K.W.; Scudder, J.D.

1983-09-01

370

Properties of scatterers in the troposphere and lower stratosphere of Uranus based on Voyager imaging data  

SciTech Connect

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 of the cloud particles is 50 percent greater at the low latitude than at the high, assuming constant mean cloud particle size. The scattering model also includes photochemically-produced stratospheric hydrocarbon ices in the upper troposphere and stratosphere, as well as an optically thick hydrogen sulfide cloud. 34 refs.

Rages, K.; Pollack, J.B.; Tomasko, M.G.; Doose, L.R. (Mycol, Inc., Sunnyvale, CA (USA) NASA, Ames Research Center, Moffett Field, CA (USA) Arizona Univ., Tucson (USA))

1991-02-01

371

The albedo, effective temperature, and energy balance of Uranus, as determined from Voyager IRIS data  

SciTech Connect

The albedo, T(eff), and energy balance of Uranus are presently derived from Voyager IR Spectrometer and Radiometer data. By obtaining the absolute phase curve of Uranus, it has become possible to evaluate the Bond albedo without making separate determinations of the geometric albedo and phase integral. An orbital mean value for the bolometric Bond albedo of 0.3 + or - 0.049 yields an equilibrium temperature of 58.2 + or - 1.0 K. Thermal spectra from pole-to-pole latitude coverage establish a T(eff) of 59.1 + or - 0.3 K, leading to an energy balance of 1.06 + or - 0.08 for Uranus. 39 refs.

Pearl, J.C.; Conrath, B.J.; Hanel, R.A.; Pirraglia, J.A.; Coustenis, A. (NASA, Goddard Space Flight Center, Greenbelt, MD (USA) Paris, Observatoire, Meudon (France))

1990-03-01

372

Saturn's rings through a microscope - Particle size constraints from the Voyager PPS scan  

SciTech Connect

The Voyager-2 photopolarimeter PPS experiment obtained the highest resolution of any ring observation of Saturn, profiling the variation of optical depth in radial steps of about 100 meters. A detailed treatment of the PPS statistics is presented here, and it is shown how these statistics can be related to the particle size distribution. An expression for the excess noise in the scan due to large particles is obtained, and the observed noise is used to constrain the upper end of the size distribution through the rings. It is shown that the Cassini Division and the C Ring have the smallest proportion of large particles, while the A ring has the largest proportion. 22 refs.

Showalter, M.R.; Nicholson, P.D. (Stanford Univ., CA (USA) Cornell Univ., Ithaca, NY (USA))

1990-10-01

373

Thickness of Saturn's Rings Inferred from Voyager 1 Observations of Microwave Scatter.  

PubMed

Earth-based telescopic observations indicate that Saturn's rings are about 1 kilometer thick, while spacecraft measurements and theoretical considerations give an upper bound of about 100 meters. Analysis of a shielding effect present in radio occultation provides a sensitive new measure of the ring thickness. On the basis of this effect, Voyager 1 microwave measurements of near-forward scatter imply a thickness ranging from less than 10 meters in ring C to about 20 and 50 meters in the Cassini division and ring A, respectively. Monolayer models do not fit the observations in the latter two regions. The discrepancy between the Earth-based and spacecraft measurements may be due to warps in the ring plane or effects of tenuous material outside the primary ring system. PMID:17829889

Zebker, H A; Tyler, G L

1984-01-27

374

'A voyage of grief and beauty': supporting a dying family member with an intellectual disability.  

PubMed

This article reports on a small research project designed to reveal what it is like to support a dying family member with an intellectual disability in a community setting. Five open-ended interviews were conducted with individuals who had experienced this phenomenon. Three thematic elements which lay within the experience of being a family support person were elucidated through hermeneutic phenomenological analysis of interview audio-recordings, verbatim transcripts and field notes. Collectively, these themes (Interlocked Companionship, Search for New Balance and Permeable Interaction) created a metaphorical understanding that participants had navigated a voyage of grief and beauty'. Rhetorical consideration of the research findings generated recommendations for tertiary, palliative care and intellectual disability support services. These are presented along with suggestions for future research. PMID:18959283

Marlow, Susan; Martin, Margi

2008-07-01

375

Preliminary Results on Saturn's Inner Plasma Sheet as Observed by Cassini: Comparison with Voyager  

NASA Astrophysics Data System (ADS)

We will present preliminary results of our analysis of Saturn's inner plasma sheet as observed by the Cassini Plasma Spectrometer (CAPS) experiment during Cassini's initial entry into Saturn's magnetosphere and when the spacecraft was put into orbit around Saturn. For this initial analysis ion fluxes are divided into two sub-groups: protons and water group ions. Depending on the status of our preliminary analysis we will discuss the ion composition and details of the fluid parameters. These results will eventually allow us to solve the force balance equation along the magnetic field (ions and electrons) and predict the vertical distribution of the plasma along the magnetic field. Once this is done we will be in a position to make detailed comparisons with the Voyager results.

Sittler, E. C.; Johnson, R. E.; Smith, H. T.; Chornay, D.; Shappirio, M. D.; Simpson, D. G.; Coates, A. J.; Rymer, A. M.; Crary, F.; McComas, D. J.; Young, D. T.; Thomsen, M. F.; Reisenfeld, D.; Hill, T. W.; Dougherty, M. K.; Andre, N.; Connerney, J. E.; Richardson, J. D.

2004-12-01

376

Preliminary Results on Saturn's Inner Plasma Sheet as Observed by Cassini: Comparison with Voyager  

NASA Astrophysics Data System (ADS)

We will present preliminary results of our analysis of Saturn's inner plasma sheet as observed by the Cassini Plasma Spectrometer (CAPS) experiment during Cassini's initial entry into Saturn's magnetosphere and when the spacecraft was put into orbit around Saturn. For this initial analysis ion fluxes are divided into two sub-groups: protons and water group ions. Depending on the status of our preliminary analysis we will discuss the ion composition and details of the fluid parameters. These results will eventually allow us to solve the force balance equation along the magnetic field (ions and electrons) and predict the vertical distribution of the plasma along the magnetic field. Once this is done we will be in a position to make detailed comparisons with the Voyager results.

Sittler, E. C.; Johnson, R. E.; Smith, H. T.; Chornay, D.; Shappirio, M. D.; Simpson, D.; Coates, A. J.; Crary, F.; McComas, D. J.; Young, D. T.; Thomsen, M.; Reisenfeld, D.; Hill, T. W.; Dougherty, M.; Andre, N.; Connerney, J. E. P.; Richardson, J. D.; Rymer, A. M.

2004-11-01

377

Gravity Probe B to test Einstein  

Microsoft Academic Search

Gravity probe B, which has been proposed for a space shuttle launch in 1992, is a 2-ton spacecraft that has been under study for several years at the Marshall Space Flight Center, Huntsville, Ala. The heart of the spacecraft is a gyroscope, which consists o f a solid quartz golfball-sized sphere that serves as the rotor. Levitated in space by

Peter M. Bell

1982-01-01

378

Synoptic observations of Jupiter's radio emissions: average statistical properties observed by voyager  

SciTech Connect

Observations of Jupiter's low-frequency radio emission collected over one-month intervals before and after each Voyager encounter have been analyzed to provide a synoptic view of the average statistical properties of the emissions. Compilations of occurrence probability, average power flux density, and average sense of circular polarization are presented as a function of central meridian longitude, phase of Io, and frequency. The results are compared with ground-based observations. The necessary geometrical conditions and preferred polarization sense for Io-related decametric emission observed by Voyager from above both the dayside and nightside hemispheres are found to be essentially the same as those observed in earth-based studies. On the other hand, there is a clear local time dependence in the Io-dependent decametric emission. The emission is prevalent at longitudes >200/sup 0/ when observed from over the dayside hemisphere but is dominant at longitudes >200/sup 0/ when observed from over the postmidnight sector. Decametric emission, which comprises the dynamic spectral lesser arcs near 10 MHz, displays a distinct, bimodal polarization pattern that is predominantly in the left-hand sense at longitudes below 150/sup 0/ and in the right-hand sense at longitudes above 150/sup 0/. The central meridian longitude distributions of occurrence probability and average flux density at hectometric wavelengths appear to depend significantly on both the observer's latitude and local time. Io appears to have an influence on average flux density of the emission down to below 2 MHz. The average power flux density sectrum of Jupiter's emission has a broad peak near 9 MHz. Intergration of the average spectrum over all frequencies and all longitudes gives a total radiated power for an equivalent isotropic source of 4 x 10/sup 11/ W.

Alexander, J.K.; Carr, T.D.; Thieman, J.R.; Schauble, J.J.; Riddle, A.C.

1981-09-30

379

Observations of sunward and tailward ion streaming in the magnetotail of Jupiter with Voyager 2  

SciTech Connect

The author has undertaken a study of the energetic ions (H, He, O, S; E greater than or equal to 200 KeV/nuc) in the Jovian magnetotail using the LECP instrument onboard Voyager 2. Seven periods of ion streaming, indicative of ion acceleration in progress in the magnetotail were found inside the magnetopause between 90-170 R/sub J/ from Jupiter. Previous work has shown the need for a local ion acceleration mechanism in the outer Jovian magnetosphere. This need could be satisfied by ion acceleration in the Jovian magnetotail. About one third of the Voyager 2 plasma sheet encounters between 90-170 R/sub J/ showed tailward or sunward ion streaming, with the rest having corotation flow directions. The ion streaming periods lasted from 10 minutes up to 4 hours and had bulk flow speeds between 900-3400 km/sec, when the data were consistent, with bulk flow of the ion population. In three events the ions were moving sunward. In the other four events the ions were moving tailward. In addition, five periods of tailward streaming were found in the magnetosheath out to a distance of 225 R/sub J/ (the limit of this study) with flow speeds of 1100-2200 km/sec, much faster than the approx.300 km/sec flow speed expected of magnetosheath flow, but not all species or intervals were consistent with bulk flow. The presence of oxygen and sulfur indicate that some of these ions are of magnetospheric origin. Conclusions from a study of these ion streams are presented briefly.

Brown, D.C.

1985-01-01

380

Pollution Probe.  

ERIC Educational Resources Information Center

|This book is written as a statement of concern about pollution by members of Pollution Probe, a citizens' anti-pollution group in Canada. Its purpose is to create public awareness and pressure for the eventual solution to pollution problems. The need for effective government policies to control the population explosion, conserve natural…

Chant, Donald A.

381

Experiments with probe masses  

PubMed Central

It is reasonable to regard the experiments performed by C. Coulomb and H. Cavendish in the end of the 18th century as the beginning of laboratory experimental physics. These outstanding scientists have measured forces (accelerations) produced by electric charges and by gravitational “charges” on probe masses that were attached to torque balance. Among the variety of different research programs and projects existing today, experiments with probe masses are still playing an important role. In this short review, the achieved and planned sensitivities of very challenging LIGO (Laser Interferometer Gravitational wave Observatory) and LISA (Laser Interferometer Space Antennae) projects are described, and a list of nonsolved problems is discussed as well. The role of quantum fluctuations in high precision measurements is also outlined. Apart from these main topics, the limitations of sensitivity caused by cosmic rays and the prospects of clock frequency stability are presented.

Braginsky, V. B.

2007-01-01

382

Stellar Occultation Probe of Triton's Atmosphere  

NASA Astrophysics Data System (ADS)

The goals of this research were (i) to better characterize Triton's atmospheric structure by probing a region not well investigated by Voyager and (ii) to begin acquiring baseline data for an investigation of the time evolution of the atmosphere which will set limits on the thermal conductivity of the surface and the total mass of N2 in the atmosphere. Our approach was to use observations (with the Kuiper Airborne Observatory) of a stellar occultation by Triton that was predicted to occur on 1993 July 10. As described in the attached reprint, we achieved these objectives through observation of this occultation and a subsequent one with the KAO in 1995. We found new results about Triton's atmospheric structure from the analysis of the two occultations observed with the KAO and ground-based data. These stellar occultation observations made both in the visible and infrared, have good spatial coverage of Triton including the first Triton central-flash observations, and are the first data to probe the 20-100 km altitude level on Triton. The small-planet light curve model of Elliot and Young (AJ 103, 991-1015) was generalized to include stellar flux refracted by the far limb, and then fitted to the data. Values of the pressure, derived from separate immersion and emersion chords, show no significant trends with latitude indicating that Triton's atmosphere is spherically symmetric at approximately 50 km altitude to within the error of the measurements. However, asymmetry observed in the central flash indicates the atmosphere is not homogeneous at the lowest levels probed (approximately 20 km altitude). From the average of the 1995 occultation data, the equivalent-isothermal temperature of the atmosphere is 47 +/- 1 K and the atmospheric pressure at 1400 km radius (approximately 50 km altitude) is 1.4 +/- 0.1 microbar. Both of these are not consistent with a model based on Voyager UVS and RSS observations in 1989 (Strobel et al, Icarus 120, 266-289). The atmospheric temperature from the occultation is 5 K colder than that predicted by the model and the observed pressure is a factor of 1.8 greater than the model.

Elliot, James L.

1998-01-01

383

Probe in the thermal collision plasma  

SciTech Connect

The flowing of electric current through the surface of a flat probe in a thermal plasma at atmospheric pressure has been considered. It has been demonstrated that the nonequilibrium ionization in the space-charge layer at the surface of the probe leads to an essential change of the current-voltage characteristic of the probe. The dependence of the current-voltage characteristic on the interphase interaction has been demonstrated.

Vishnyakov, V. I. [Mechnikov Odessa National University, Odessa 65082 (Ukraine)

2007-01-15

384

33 CFR 151.2037 - If my vessel cannot conduct ballast water management practices because of its voyage and/or...  

Code of Federal Regulations, 2010 CFR

...vessel cannot conduct ballast water management practices because of its voyage...AND BALLAST WATER Ballast Water Management for Control of Nonindigenous...vessel cannot conduct ballast water management practices because of its...

2010-07-01

385

33 CFR 151.2037 - If my vessel cannot conduct ballast water management practices because of its voyage and/or...  

Code of Federal Regulations, 2010 CFR

...vessel cannot conduct ballast water management practices because of its voyage...AND BALLAST WATER Ballast Water Management for Control of Nonindigenous...vessel cannot conduct ballast water management practices because of its...

2009-07-01

386

Magnetoptical Probes  

Microsoft Academic Search

The necessity of probe validation of widely used iron oxide particles in molecular magnetic resonance imaging (mMRI) has called\\u000a for a growing demand for simple detection and quantification methods in vitro and ex vivo. A simple option to adapt these\\u000a particles to standard methods of biological research such as microscopy and flow cytometry is the conjugation of fluorescent\\u000a dyes. With

Eyk Schellenberger

387

Surface morphology implications on Langmuir probe measurements  

NASA Astrophysics Data System (ADS)

Langmuir probes are extensively employed to study the plasmas in space and laboratory environments. Successful measurements require a comprehensive modeling of both the plasma environment and the probe conditions in the form of current collection models. In this thesis, the surface morphology implications on the probe current collection are investigated. This problem is applied and solved in the context of a CubeSat regime. The first problem that is investigated is the consequence of surface structural variability on the current measurements. A new model for dealing with non-uniformity of the probe surface structure is developed in this paper. This model is applied to analyze the Langmuir probe data from a sounding rocket mission that was subjected to surface structural non-homogeneities. This model would be particularly useful for CubeSat platforms where elaborate probe design procedures are not feasible. The second problem that is investigated is the surface area implications on Langmuir probe measurements. It has been established that surface area ratio of the spacecraft to that of the probe needs to be sufficiently large to make successful plasma measurements. CubeSats would therefore pose a challenge for employing Langmuir-type instruments to study the space plasma. We inspect the feasibility of making plasma measurements using Langmuir probes subjected to CubeSat area constraints. This analysis is done for a forthcoming Utah State University (USU)/Space Dynamics Lab (SDL) CubeSat mission.

Suresh, Padmashri

388

HHMS-PI modeling of the solar wind with pick-up protons from the Sun to Voyager 2  

NASA Astrophysics Data System (ADS)

Our 3D time-dependent magnetohydrodynamic (MHD) solar wind model, the Hybrid Heliospheric Modeling System with Pickup Protons (HHMS-PI) (Detman et al., 2011) has been extended to Voyager 2. HHMS-PI uses a time-dependent lower boundary condition at 0.1 AU driven indirectly by solar observations via the Wang-Sheeley-Arge source surface current sheet model (Arge and Pizzo, 2000). We show results for the Halloween 2003 solar events for the solar wind and pickup protons throughout the heliosphere extending beyond Voyager 2 (at 73 AU) to 75 AU. We also show the latitudinal and longitudinal extent of the interplanetary propagation of these events. This work was funded by NASA Grant NNX08AE40G and by Carmel Research Center, Inc.

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

2011-12-01

389

Implications of Generalized Rankine-Hugoniot Conditions for the PUI Population at the Voyager 2 Termination Shock  

Microsoft Academic Search

The Rankine-Hugoniot (R-H) jump conditions at the heliospheric termination shock provide a means of knitting together the in situ measurements from Voyager 2 (VGR2) with the remote sensing of the heliosheath plasma via energetic neutral atom (ENA) imaging by IBEX and Cassini?INCA. The VGR2 instrument suite has a gap (?1–30 keV) in the ion measurements. While the ENA images (0.2–6

E. C. Roelof; S. M. Krimigis; D. G. Mitchell; R. B. Decker; J. D. Richardson; M. Gruntman; H. O. Funsten

2010-01-01

390

Implications of Generalized Rankine-Hugoniot Conditions for the PUI Population at the Voyager 2 Termination Shock  

Microsoft Academic Search

The Rankine-Hugoniot (R-H) jump conditions at the heliospheric termination shock provide a means of knitting together the in situ measurements from Voyager 2 (VGR2) with the remote sensing of the heliosheath plasma via energetic neutral atom (ENA) imaging by IBEX and Cassini\\/INCA. The VGR2 instrument suite has a gap (~1-30 keV) in the ion measurements. While the ENA images (0.2-6

E. C. Roelof; S. M. Krimigis; D. G. Mitchell; R. B. Decker; J. D. Richardson; M. Gruntman; H. O. Funsten

2010-01-01

391

Pickup protons and pressure-balanced structures from 39 to 43 AU: Voyager 2 observations during 1993 and 1994  

Microsoft Academic Search

structures observed by Voyager 2 from 39.3 to 40.6 AU in 1993 and from 42.6 to 43.2 AU during 1994. The pickup proton temperature is high in the region of the distant heliosphere that we considered: (5.4 +_ 0.1) x 106 K at 39-41 AU and (6.0 +_ 0.4) x 106 K at 43 AU. The densi_ty of the pickup

L. F. Burlaga; N. F. Ness; J. W. Belcher; Y. C. Whang

1996-01-01

392

Latitudinal and field-aligned cosmic ray gradients 2 to 5 AU Voyages 1 and 2 and IMP 8  

SciTech Connect

Latitudinal and field-aligned cosmic ray gradients have been measured separately by inter-normalization of the similar integral response (greater than approximately 30 MeV/nucleon) and high counting rates of approximately 60 counts per second of the anticoincidence detectors of the LECP experiment on Voyagers 1 and 2 and the CPME experiment on IMP 8. The unambiguous separation of latitudinal from field-aligned gradients in long-lived (greater than 10 days) cosmic ray structures is possible because during their Earth-Jupiter transits, the two Voyagers are never separated by more than a few degrees in latitude or longitude, or by more than 8% of the helioradius of either spacecraft, and because the Voyagers remain magnetically well-connected to Earth, which allows a direct estimate of field-aligned gradients. The IMF connection is estimated by using the solar wind velocities measured by the PLS experiment on Voyager 1. Latitudinal gradients of approximately 2 to 5%/deg are found in short-lived (10 to 30 days) structures, while they are approximately 1 to 2%/deg in structures recurring over several solar rotations. Radial gradients, except in the onsets of Forbush decreases, are commonly approximately 2%/AU, although there are rotations on which neither a radial nor a latitudinal gradient is measurable above 1%/AU or 1%/deg. Application of diffusion-convection theory to these gradients shows that if one assumes that diffusion dominates transport transverse to the magnetic field, one obtains an upper bound on the transverse mean free path for scattering lambda/sub perpendicular/ much less than 10/sup -3/ AU at 1 GeV/nucleon, which is inconsistent with values predicted by diffusion theory.

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

1983-12-01

393

General characteristics of hot plasma and energetic particles in the Saturnian magnetosphere: Results from the Voyager spacecraft  

Microsoft Academic Search

The low energy charged particle (LECP) experiment on the Voyager 1 and 2 spacecraft made measurements of the intensity, energy spectra, and spatial distributions of ions (30 keV< or approx. =E< or approx. =150 MeV) and electrons (22 keV< or approx. =E< or approx. =20 MeV) during encounters with the Saturnian magnetosphere in November 1980 and August 1981, respectively. Detailed

S. M. Krimigis; J. F. Carbary; E. P. Keath; T. P. Armstrong; L.J. Lanzerotti; G. Gloeckler

1983-01-01

394

Cosmic ray investigation for the Voyager missions; energetic particle studies in the outer heliosphere—And beyond  

Microsoft Academic Search

A cosmic-ray detector system (CRS) has been developed for the Voyager mission which will measure the energy spectrum of electrons from ˜3–110 MeV and the energy spectra and elemental composition of all cosmic-ray nuclei from hydrogen through iron over an energy range from ˜ 1–500 MeV\\/nuc. Isotopes of hydrogen through sulfur will be resolved from ˜ 2–75 MeV\\/nuc. Studies with

E. C. Stone; R. E. Vogt; F. B. McDonald; B. J. Teegarden; J. H. Trainor; J. R. Jokipii; W. R. Webber

1977-01-01

395

Composition and Thermal Profiles of the Jovian Upper Atmosphere Determined by the Voyager Ultraviolet Stellar Occultation Experiment  

Microsoft Academic Search

Occultation of the star Regulus--a Leo---by the Jovian atmosphere was monitored by the Voyager 2 spacecraft on July 9, 1979. The absorption recorded in the 910-1200  range was caused primarily by the H2-Lyman and Werner bands. These data provide the first complete measurements of atmospheric density and temperature profiles between 330 and 830 km above the ammonia cloud tops.

M. C. Festou; S. K. Atreya; T. M. Donahue; B. R. Sandel; D. E. Shemansky; A. L. Broadfoot

1981-01-01

396

The 3-D effects in the long-term solar wind speed rise observed by Voyager 2 in early 1994  

Microsoft Academic Search

In early 1994, Voyager 2 at 42-43 AU near heliolatitude 10 deg S observed over a period of approximately 100 days a remarkable sequence of quasi-recurrent stream fronts, wherein the background (ambient) speed rose steadily from approximately 450 to approximately 550 km\\/s while the mean period of the streams decreased from the usual 25 days down to approximately 20 days.

V. J. Pizzo; K. I. Paularena; J. D. Richardson; A. J. Lazarus; J. W. Belcher

1995-01-01

397

Voyager 2 radio science observations of the uranian system: atmosphere, rings, and satellites.  

PubMed

Voyager 2 radio occultation measurements of the Uranian atmosphere were obtained between 2 and 7 degrees south latitude. Initial atmospheric temperature profiles extend from pressures of 10 to 900 millibars over a height range of about 100 kilometers. Comparison of radio and infrared results yields mole fractions near the tropopause of 0.85 and 0.15 +/- 0.05 for molecular hydrogen and helium, respectively, if no other components are present; for this composition the tropopause is at about 52 kelvins and 110 millibars. Distinctive features in the signal intensity measurements for pressures above 900 millibars strongly favor model atmospheres that include a cloud deck of methane ice. Modeling of the intensity measurements for the cloud region and below indicates that the cloud base is near 1,300 millibars and 81 kelvins and yields an initial methane mole fraction of about 0.02 for the deep atmosphere. Scintillations in signal intensity indicate small-scale stucture throughout the stratosphere and upper troposphere. As judged from data obtained during occultation ingress, the ionosphere consists of a multilayer structure that includes two distinct layers at 2,000 and 3,500 kilometers above the 100-millibar level and an extended topside that may reach altitudes of 10,000 kilometers or more. Occultation measurements of the nine previously known rings at wavelengths of 3.6 and 13 centimeters show characteristic values of optical depth between about 0.8 and 8; the maxim value occurs in the outer region of the in ring, near its periapsis. Forward-scattered signals from this ring have properties that differ from those of any of Saturn's rings, and they are inconsistent with a discrete scattering object or local (three-dimensional) assemblies of orbiting objects. These signals suggest a new kdnd of planetary ring feature characterized by highly ordered cylindrical substructures of radial scale on the order of meters and azimuthal scale of kilometers or more. From radio data alone the mass of the Uranian system is GM(sys) = 5,794,547- 60 cubic kilometers per square second; from a combination of radio and optical navigation data the mass of Uranus alone is GM(u) = 5,793,939+/- 60 cubic kilometers per square second. From all available Voyager data, induding imaging radii, the mean uncompressed density of the five major satellites is 1.40+/- 0.07 grams per cubic centimeter; this value is consistent with a solar mix of material and apparently rules out a cometary origin of the satellites. PMID:17812893

Tyler, G L; Sweetnam, D N; Anderson, J D; Campbell, J K; Eshleman, V R; Hinson, D P; Levy, G S; Lindal, G F; Marouf, E A; Simpson, R A

1986-07-01

398

Signatures of the July 2000 Solar Disturbances Observed at Voyagers 1 and 2 during 2001  

NASA Astrophysics Data System (ADS)

Intense solar activity during July 2000 (including the well-documented July 14, Bastille Day, geomagnetic storm) produced high intensities of energetic particles and multiple large-scale solar wind disturbances at 1AU. These disturbances coalesced into a complex global merged interaction region (GMIR) that passed the Voyagers in early 2001 [1,2]. We discuss the effects this GMIR had on energetic (>0.5 MeV) proton intensities measured by the LECP (Low Energy Charged Particle) instruments on Voyagers 1 (V1) and 2 (V2). The shock at the forward edge of the GMIR passed V2 (63AU, 22° S) on 2001 DOY 12 (2001.03), with observed properties in excellent agreement with predictions [3]. The shock evidently swept up and accelerated ?3-20 MeV ACR protons that began to increase some two weeks before the shock's passage. However, the ?0.5-1.5 MeV protons peaked ~15 days after the shock arrival (with a time width ~30 days), due possibly to the shock's progressive weakening, which reduced its ability to accelerate ambient protons as it propagated outward. The GMIR evidently reached V1 (80.5AU, 33.7° N) ~60 days later (on 2001.2), based on Forbush decreases observed in the intensities of ACR and GCR protons >20 MeV; it is not clear if there was a leading shock at V1. At V1 the intensity increase of ?0.5-1.5 MeV protons was a factor ~2 less than that at V2, but had a time duration ~2 times longer than that at V2. These, as well as other differences in the intensity-time profiles of >0.5 MeV protons observed at V2 and V1 are not unexpected, particularly in view of the ~60° latitudinal separation of the two spacecraft. [1] Krimigis et al., Proc. of ICRC 2001, 3637-3640 (2001). [2] McDonald et al., Proc. of ICRC 2001, 3607-3610 (2001). [3] Wang et al., J. Geophys. Res. 106, 13,007-13,013 (2001).

Decker, R. B.; Krimigis, S. M.

2001-12-01

399

The Vision for Space Exploration  

NASA Astrophysics Data System (ADS)

The Vision, announced by President Bush in January 2004, will extend humanity's presence across the solar system, starting with a return to the moon by the end of the next decade, followed by journeys to Mars and beyond. Building on the best of Apollo and shuttle technology, NASA's 21st century exploration system will be affordable, reliable, versatile and safe. The exploratory voyages of the next few decades have the potential, in this lifetime, to answer age-old questions about how life begins, whether life exists elsewhere, and how the inevitable discoveries along the way will help better our lives here on Earth. Over the next century, the Vision for Space Exploration will set in motion activities to improve our understanding of age-old questions, and inspire new generations to pursue math and science. We'll see new industries and technologies evolve and discoveries that will benefit all.

Griffin, M.

2005-12-01

400

Deep space observations of the east-west asymmetry of solar energetic storm particle events - Voyagers 1 and 2  

Microsoft Academic Search

It has been well established that solar flare shock waves, propagating through the interplanetary medium, accelerate ambient energetic particles, giving rise to the formation of energetic storm particle (ESP) intensity enhancements. However, the acceleration mechanism which is responsible for the generation of ESP events is still under investigation. In the present investigation, energetic proton observations during solar flare ESP events

E. T. Sarris; R. B. Decker; S. M. Krimigis

1985-01-01

401

Probing space-time through numerical simulations  

NASA Astrophysics Data System (ADS)

Einstein's equations describe gravity using an elegant but complicated set of equations. Finding astrophysically relevant solutions to these equations requires the most sophisticated numerical algorithms and powerful supercomputers available. The search for astrophysical solutions has made numerical relativity one of the most active areas of research in gravitational physics. Of particular interest in numerical relativity has been simulating the inspiral and coalescence of compact binaries involving black holes and neutrons stars. The outcome from these simulations will bring general relativity into harmony with the observations of gravitational radiation that are expected to take place in the immediate future. This article highlights current progress in numerical relativity. It also attempts to envision the future of this field and its integration with gravitational wave astronomy.

Laguna, Pablo

2005-11-01

402

Pioneer III and IV Space Probes  

Microsoft Academic Search

A description of the over-all objectives of the Pioneer III and IV experiments is presented. Included is an analysis of the payload design philosophy, a description of the flight hardware, and a synopsis of the results of the experiments.

H. Curtis; D. Schneiderman

1960-01-01

403

Orbit mechanics of deep space probes  

Microsoft Academic Search

Emphasized are orbits with high inclinations from the earth-moon orbital plane, with initial major axes oriented perpendicularly or inclined to the axis of syzygies and with period near that of the moon. The relation of this problem to the restricted problem of three and four bodies is discussed, showing the effects of luni-solar ephemerides versus the 'circular problem'. Various modifications

J. J. F. Liu; J. Segrest; V. Szebehely

1986-01-01

404

Insights gained using HHMS-PI from the Sun to Voyager 2  

NASA Astrophysics Data System (ADS)

We extended the three-dimensional (3D) time-dependent magnetohydrodynamic (MHD) Hybrid Heliospheric Modeling System with Pickup Protons (HHMS-PI) [1] out to Voyager 2 (V2) and to 75 AU. HHMS-PI starts at the Sun and uses pre-and post-event background mode source surface (SS) solar inputs and solar event inputs. Our scientific results include good agreement between the HHMS-PI simulated parameters of the solar wind (SW) and interplanetary magnetic field (IMF) measurements at ACE, Ulysses, and Cassini. HHMS-PI simulates well the strong shocks observed at ACE, Ulysses, and Cassini associated with the Halloween 2003 solar events. This agreement indicates that HHMS-PI can provide good simulations for the Sedov strong shock limit. Comparisons between HHMS-PI simulated shock propagation from the Sun to Ulysses and Cassini and the spacecraft measurements of shock arrivals indicates that pickup protons slow the propagation of shocks to Ulysses and Cassini. Our simulations also demonstrate the importance of asymmetric flows in latitude and in longitude. For the Halloween 2003 solar events the HHMS-PI simulations show the large extent in latitude and in longitude of the shocks. The HHMS-PI simulations also indicate that IMF sector boundaries are greatly affected by the SW/IMF.

Intriligator, Devrie S.; Detman, Thomas; Dryer, Murray; Intriligator, James; Sun, Wei; Webber, William R.; Deehr, Charles

2012-05-01

405

Update on Voyager 2 High Energy Ions in the Outer Heliosphere and Heliosheath  

NASA Astrophysics Data System (ADS)

We continue to investigate the High Energy Ions (HEIs) we first reported in Intriligator et al., JGR (2010). These elevated HEI detections are found in the Voyager 2 (V2) PLS (Plasma Subsystem) data on the sunward facing B-Cup at the energy/unit charge (E/Q) step 12 corresponding to 1610 volts and a proton speed of ~ 600 km/s. We associated the V2 HEI detections in 2007 with V2 being in the vicinity of the termination shock. In the present paper we update our findings and present V2 data from other periods of interest including 2004 when V2 was measuring the effects from the October-November (Halloween) 2003 solar events; and 2008/9 when V2 was in the heliosheath. We believe that it is possible to see the link between solar activity and HEI detections in the V2 data from 2004. At solar minimum when V2 was in the heliosheath, we see almost no such HEI detections. We put the V2 HEI PLS data in the context of the simultaneous V2 PLS convective bulk plasma flow data, and the simultaneous V2 data from other experiments including the cosmic ray subsystem (CRS), the low energy charged particle (LECP), and the magnetic field. Our results suggest that the V2 HEI detections are the result of one or more underlying physical phenomena that we shall discuss.

Intriligator, D. S.; Intriligator, J.; Miller, W. D.; Webber, W. R.; Decker, R. B.; Sittler, E. C.

2010-12-01

406

Pickup ion dynamics at the heliospheric termination shock observed by Voyager 2  

NASA Astrophysics Data System (ADS)

The recent Voyager 2 (V2) observations of the termination shock (TS) indicate that it is a plasma shock unlike any other in the heliosphere with the dynamics and structure heavily influenced by the presence of an energized population of pickup ions (PUIs). The `unexpected' finding of cold plasma downstream of the TS in the heliosheath, corresponding to very little heating of the thermal solar wind, suggests that the energy dissipated by the shock is dominated by the energization of PUIs at the TS. We examine the `shock surfing' mechanism at the test particle level, where multiply reflected ions (MRIs) gain energy from the motional electric field as a consequence of reflection from the cross-shock potential, for a model of the TS3 (the third TS crossing measured by V2). The energization of PUI filled-shell distributions at a stationary, perpendicular model of the TS3 indicates that shock surfing can provide both substantial PUI acceleration and a dissipation mechanism at the TS. For a sufficiently strong cross-shock potential and sufficiently narrow shock ramp MRI acceleration can account for the `missing' energy of the downstream solar wind plasma.

Burrows, R. H.; Zank, G. P.; Webb, G. M.

2010-12-01

407

Pickup Ion Dynamics at the Heliospheric Termination Shock Observed by Voyager 2  

NASA Astrophysics Data System (ADS)

The recent Voyager 2 (V2) observations of the termination shock (TS) indicate that it is a plasma shock unlike any other in the heliosphere with the dynamics and structure heavily influenced by the presence of an energized population of pickup ions (PUIs). The "unexpected" finding of cold plasma downstream of the TS in the heliosheath, corresponding to very little heating of the thermal solar wind (SW), suggests that the energy dissipated by the shock is dominated by the energization of PUIs at the TS. We examine the "shock surfing" mechanism at the test particle level, where multiply reflected ions (MRIs) gain energy from the motional electric field as a consequence of reflection from the cross-shock potential (CSP), for a model of the TS3 (the third TS crossing measured by V2). The energization of PUI filled-shell distributions at a stationary, perpendicular model of the TS3 indicates that shock surfing can provide both substantial PUI acceleration and a dissipation mechanism at the TS. For a sufficiently strong CSP and sufficiently narrow shock ramp MRI acceleration can account for the "missing" energy of the downstream SW plasma.

Burrows, R. H.; Zank, G. P.; Webb, G. M.; Burlaga, L. F.; Ness, N. F.

2010-06-01

408

Spatial irregularities in Jupiter's upper ionosphere observed by voyager radio occultations  

SciTech Connect

Dual frequency radio occultation experiments carried out with Voyagers 1 and 2 provided data on the spatial irregularities in Jupiter's ionosphere at four different locations. Sample spectra of weak fluctuations in amplitude and phase of the 3.6-cm and 13-cm wavelength radio signals can be interpreted by using the theory for scattering from an anisotropic power law phase screen. Least squares solutions for ionospheric parameters derived from the observed fluctuation spectra yielded estimates of (1) the axial ratio, (2) angular orientation of the anisotropic irregularities, (3) the power law exponent of the spatial spectrum of irregularities, and (4) the magnitude of the spatial variations in electron density. Equipment limitations and the method of analysis constrain the observations to irregularities of approximate size 1--200 km. No evidence of the inner or outer scale of the irregularities was found. For length scales in the range given, the three-dimensional spatial spectrum obeys a power law with exponent varying from -3.0 to -3.7, and the root mean square fractional variations in electron density are 1--15%. All observed irregularities appear to be anisotropic with axial ratios between 2:1 and 10:1. Ionospheric parameters vary with altitude and latitude. We conclude that the measured angular orientation of the anisotropic irregularities indicates magnetic field direction and may provide a basis for refining Jovian magnetic field models.

Hinson, D.P.; Tyler, G.L.

1982-07-01

409

Size estimates of Titan's aerosols based on Voyager high-phase-angle images  

NASA Astrophysics Data System (ADS)

Limits on the physical properties of the scattering haze near the top of Titan's atmosphere are derived from data obtained from seven high-phase-angle images from Voyager 1 and 2. From the ratio of the intensities observed at two different high phase angles, an estimate can be made of the forward-scattering lobe of the single-scattering phase function. Comparing the forward-scattering estimate with diffraction lobes from particles of different radii, it is concluded that the average radius of the particles found in the upper few tenths of an optical depth exceeds 0.19 micron. Judging from data observed at four different phase angles, the haze particles probably have a refractive index near 1.6 and a mean size of about 0.5 micron, if the widths of their diffraction peaks are close to those for equal-volume spheres. However, the highly polarizing nature of the particles over a broad wavelength-bandpass (Tomasko and Smith, 1982; West et al, 1983) combined with their forward-scattering behavior makes it very unlikely that the particles are spherical. The nonsphericity contributes to the uncertainty about the radii of the particles, but it is thought that the average radius is several tenths of a micron.

Rages, K.; Pollack, J. B.; Smith, P. H.

1983-11-01

410

Photometry from Voyager 2: Initial results from the Neptunian atmosphere, satellites, and rings  

SciTech Connect

The Voyager photopolarimeter successfully accomplished its objectives for the Neptune encounter, performing measurements on the planet, several of its satellites, and its ring system. A photometric map of Neptune at 0.26 micrometer ({mu}m) shows the planet to be bland, with no obvious contrast features. No polar haze was observed. At 0.75 {mu}m, contrast features are observed, with the Great Dark Spot appearing as a low-albedo region and the bright companion as being substantially brighter than its surroundings, implying it to be at a higher altitude than the Great Dark Spot. Triton's linear phase coefficients of 0.011 magnitudes per degree at 0.26 {mu}m and 0.013 magnitudes per degree at 0.75 {mu}m are consistent with a solid-surface object possessing high reflectivity. Preliminary geometric albedos for Triton, Nereid, and 1989N2 were obtained at 0.26 and 0.75 {mu}m. Triton's rotational phase curve shows evidence of two major compositional units on its surface. A single stellar occultation of the Neptune ring system elucidated an internal structure in 1989N1R, in the {approximately}50-kilometer region of modest optical depth. 1989N2R may have been detected. The deficiency of material in the Neptune ring system, when compared to Uranus', may imply the lack of a recent moon shattering event.

Lane, A.L.; West, R.A.; Nelson, R.M.; Horn, L.J.; Buratti, B.J.; Wallis, B.D.; Yanamandra-Fisher, P.; Bliss, D.A.; Mayo, M.J.; Smythe, W.D. (California Institute of Technology, Pasadena (USA))

1989-12-15

411

Voyager Observations of Diffuse Far-Ultraviolet Continuum and Line Emission in Eridanus  

NASA Astrophysics Data System (ADS)

We present Voyager observations of the diffuse far-ultraviolet radiation field (912 Ĺ-1150 Ĺ) in two regions of the Eridanus superbubble A strong continuum is present in both locations which we have identified with starlight scattered by interstellar dust. From the level of this emission (1620‰150 photons cm-2 s-1 sr-1 Ĺ-1) we have placed a lower limit of about 0.3 on the albedo if the scattering is isotropic and an upper limit of about 0.8 on the phase function asymmetry factor (g) if the grains are perfectly reflecting. In addition, O VI (??1032/1038) emission with an intensity of 28.7ą2.8 × 104 photons cm-2 s-1 sr-1 is apparent in one of the two locations, and C III (977 Ĺ) is visible in both locations with intensities of 2.14ą0.75 × 104 and 18.9ą1.7 × 104 photons cm-2 s-1 sr-1. The line ratios indicate shock velocities on the order of 90 km s-1 in one of the targets and 180 km s-1 in the other, which is located near a peak of the C-band X-ray emission.

Murthy, Jayant; Im, M.; Henry, R. C.; Holberg, J. B.

1993-12-01

412

Multispectral and geomorphic studies of processed Voyager 2 images of Europa  

NASA Astrophysics Data System (ADS)

High resolution images of Europa taken by the Voyager 2 spacecraft were used to study a portion of Europa's dark lineations and the major white line feature Agenor Linea. Initial image processing of images 1195J2-001 (violet filter), 1198J2-001 (blue filter), 1201J2-001 (orange filter), and 1204J2-001 (ultraviolet filter) was performed at the U.S.G.S. Branch of Astrogeology in Flagstaff, Arizona. Processing was completed through the stages of image registration and color ratio image construction. Pixel printouts were used in a new technique of linear feature profiling to compensate for image misregistration through the mapping of features on the printouts. In all, 193 dark lineation segments were mapped and profiled. The more accurate multispectral data derived by this method was plotted using a new application of the ternary diagram, with orange, blue, and violet relative spectral reflectances serving as end members. Statistical techniques were then applied to the ternary diagram plots. The image products generated at LPI were used mainly to cross-check and verify the results of the ternary diagram analysis.

Meier, T. A.

1984-08-01

413

Mapping potential vorticity dynamics on saturn: Zonal mean circulation from Cassini and Voyager data  

NASA Astrophysics Data System (ADS)

Maps of Ertel potential vorticity on isentropic surfaces (IPV) and quasi-geostrophic potential vorticity (QGPV) are well established in dynamical meteorology as powerful sources of insight into dynamical processes involving 'balanced' flow (i.e. geostrophic or similar). Here we derive maps of zonal mean IPV and QGPV in Saturn's upper troposphere and lower stratosphere by making use of a combination of velocity measurements, derived from the combined tracking of cloud features in images from the Voyager and Cassini missions, and thermal measurements from the Cassini Composite Infrared Spectrometer (CIRS) instrument. IPV and QGPV are mapped and compared for the entire globe between latitudes 89?S-82?N. As on Jupiter, profiles of zonally averaged PV show evidence for a step-like "stair-case" pattern suggestive of local PV homogenisation, separated by strong PV gradients in association with eastward jets. The northward gradient of PV (IPV or QGPV) is found to change sign in several places in each hemisphere, however, even when baroclinic contributions are taken into account. The stability criterion with respect to Arnol'd's second stability theorem may be violated near the peaks of westward jets. Visible, near-IR and thermal-IR Cassini observations have shown that these regions exhibit many prominent, large-scale eddies and waves, e.g. including 'storm alley'. This suggests the possibility that at least some of these features originate from instabilities of the background zonal flow.

Read, P. L.; Conrath, B. J.; Fletcher, L. N.; Gierasch, P. J.; Simon-Miller, A. A.; Zuchowski, L. C.

2009-12-01

414

The Global Configuration of the Heliosheath Inferred from Recent Voyager 1 Observations  

NASA Astrophysics Data System (ADS)

Recent observations from Voyager 1 in the nose region of the heliosheath, an area created by the motion of the Sun through the local interstellar medium, have revealed that: (1) beyond ~113 AU from the Sun, the anisotropy of low-energy ions becomes very small in all directions, which has been interpreted as indicating that the solar wind flow speed has decreased to near zero; (2) at ~120 AU, anomalous cosmic rays (ACRs) are accelerated to their highest energies; and (3) at ~122 AU, there is a precipitous decrease both in ACRs and in termination shock particles (TSPs) that are convected downstream from the termination shock. In this paper, the low-energy anisotropy observations are interpreted as implying, not that the solar wind flow speed has decreased to near zero, but rather that the solar wind flow is closely aligned with the magnetic field direction, which is observed to be in the azimuthal direction. A simple model for the heliosheath is then constructed, based on the anisotropy observations and the observational evidence that the dominant pressure is contained in pickup ions, TSPs, and ACRs. The model predicts that there are jets of supersonic and super-Alfvénic solar wind flowing along the flanks of the heliosheath, stretching and opening the heliosheath magnetic field into the interstellar medium. TSPs and ACRs that are accelerated in the nose region can easily escape along the magnetic field in the open region of the heliosheath, resulting in the precipitous decrease in the intensity of TSPs and ACRs.

Fisk, L. A.; Gloeckler, G.

2013-10-01

415

Nature and evolution of magnetohydrodynamic fluctuations in the solar wind: Voyager observations  

SciTech Connect

The magnetic field and plasma data collected by the Voyager spacecraft between 1 and 11 AU are used to study the properties of interplanetary MHD fluctuations and to attempt to answer several related questions about the Alfvenicity of solar wind fluctuations; First, to what extent are magnetic and velocity fluctuations Alfvenic. Second, does the dominant propagation direction of Alfvenic fluctuations evolve with heliocentric distance. Third, is the presence of Alfvenic fluctuations correlated with large-scale structures, such as stream interaction regions. In addition, we investigated the contributions of compressive modes to the interplanetary fluctuations. We find that near 1 AU at most 15% of the fluctuations at the scale of a few hours or less are purely Alfvenic and these usually propagate outward from the Sun. The propagation direction becomes more inward on average with increasing heliocentric distance. Although it is commonly supposed that compression regions are not generally Alfvenic, we found that the wave propagation direction is only slightly more mixed in compression regions than in the corresponding rarefaction regions. Moreover, the evolution in propagation direction is not directly due to the growth of large-scale compression regions. There is a tendency for magnetic fluctuations to be larger than velocity fluctuations at scales less than a day, while the reverse is true, due to the dominance of stream energy, at larger scales.

Roberts, D.; Klein, L.W.; Goldstein, M.L.; Matthaeus, W.H.

1987-10-01

416

On the Voyager 1 Zero Radial Velocity Measurements in the Inner Heliosheath  

NASA Astrophysics Data System (ADS)

Theoretical analysis of the Voyager 1 data revealed a very small, or even negative, value of the solar wind (SW) radial velocity component. This should not be surprising if we take into account time-dependent processes that take place in the inner heliosheath (IHS). We analyze solar cycle modeling of the SW interaction with the local interstellar medium (LISM) and demonstrate the existence of small and negative values of the SW radial velocity. It shown that, in reality, a similar picture can be observed in the outer heliosheath (OHS), where on the contrary, extended regions of the positive radial velocity are observed. Another scenario discussed in this talk is related to effects of transients, such as global merged interaction regions and corotating interacting regions. Numerical results are obtained with the SW-LISM interaction model developed in the UAHuntsville and implemented in the Multi-Scale Fluid-Kinetic Simulation Suite. This model treats ions magnetohydrodynamically while the transport of neutral atoms is performed kinetically by solving the Boltzmann equation with a Monte Carlo approach or using a multi-fluid approach developed in mid-90's by G. P. Zank. Pickup ions (PUIs) can be treated as a separate fluid. The evolution of the PUI-generated turbulence is addressed on the differential level by adding three additional equations, which are solved self-consistently with the MHD-kinetic system of equations.

Pogorelov, N. V.; Borovikov, S. N.; Kryukov, I.; Zank, G. P.

2011-12-01

417

Remote sensing of the magnetic moment of uranus: predictions for voyager.  

PubMed

Power is supplied to a planet's magnetosphere from the kinetic energy of planetary spin and the energy flux of the impinging solar wind. A fraction of this power is available to drive numerous observable phenomena, such as polar auroras and planetary radio emissions. In this report our present understanding of these power transfer mechanisms is applied to Uranus to make specific predictions of the detectability of radio and auroral emissions by the planetary radio astronomy (PRA) and ultraviolet spectrometer (UVS) instruments aboard the Voyager spacecraft before its encounter with Uranus at the end of January 1986. The power available for these two phenomena is (among other factors) a function of the magnetic moment of Uranus. The date of earliest detectability also depends on whether the predominant power source for the magnetosphere is planetary spin or solar wind. The magnetic moment of Uranus is derived for each power source as a function of the date of first detection of radio emissions by the PRA instrument or auroral emissions by the UVS instrument. If we accept the interpretation of ultraviolet observations now available from the Earth-orbiting International Ultraviolet Explorer satellite, Uranus has a surface magnetic field of at least 0.6 gauss, and more probably several gauss, making it the largest or second-largest planetary magnetic field in the solar system. PMID:17777779

Hill, T W; Dessler, A J

1985-03-22

418

PICKUP ION DYNAMICS AT THE HELIOSPHERIC TERMINATION SHOCK OBSERVED BY VOYAGER 2  

SciTech Connect

The recent Voyager 2 (V2) observations of the termination shock (TS) indicate that it is a plasma shock unlike any other in the heliosphere with the dynamics and structure heavily influenced by the presence of an energized population of pickup ions (PUIs). The 'unexpected' finding of cold plasma downstream of the TS in the heliosheath, corresponding to very little heating of the thermal solar wind (SW), suggests that the energy dissipated by the shock is dominated by the energization of PUIs at the TS. We examine the 'shock surfing' mechanism at the test particle level, where multiply reflected ions (MRIs) gain energy from the motional electric field as a consequence of reflection from the cross-shock potential (CSP), for a model of the TS3 (the third TS crossing measured by V2). The energization of PUI filled-shell distributions at a stationary, perpendicular model of the TS3 indicates that shock surfing can provide both substantial PUI acceleration and a dissipation mechanism at the TS. For a sufficiently strong CSP and sufficiently narrow shock ramp MRI acceleration can account for the 'missing' energy of the downstream SW plasma.

Burrows, R. H.; Zank, G. P.; Webb, G. M. [Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, AL 35805 (United States); Burlaga, L. F. [NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Ness, N. F. [The Catholic University of America, Washington DC 20064 (United States)

2010-06-01

419

Constraints on Saturn's E Ring from the Voyager 1 Radio Astronomy Instrument  

NASA Astrophysics Data System (ADS)

We have reanalyzed the data acquired by the planetary radioastronomy (PRA) experiment during the passage of Voyager 1 through Saturn's E ring. Depending on the distance from the ring plane, the instrument detected (i) dust grain impacts on the spacecraft and/or (ii) plasma waves or noise. The signal produced by the dust can be recognized by its power spectrum. It is dominant in a region of ?12,000 km vertical extent around the ring plane, and has a maximum at roughly 5000 km southward of equator (at 6.1 RSfrom Saturn). Assuming that the grain concentration is given by the model of Showalter et al.(Showalter, M. R., J. N. Cuzzi, and S. M. Larson 1991. Icarus94, 451-473) derived from optical observations, we infer from the mean PRA voltage and from the histogram of the data that the particles have a mean radius r? 1 ?m and a narrow size distribution of fractional dispersion between 10 and 30%. These values agree with the above model. We have also investigated the ring thickness. The PRA signal has a full vertical width at half-maximum of ?8000 km, which is 2.3 times less than that given by the optical model. Since the signal produced by the dust varies strongly with the grain size (as r6), our measurements can be made compatible with the optical observations if the particle mean size decreases slightly with vertical distance, by about 10% over 4000 km.

Meyer-Vernet, Nicole; Lecacheux, Alain; Pedersen, Bent M.

1996-09-01

420

100 GHz wafer probes based on photoconductive sampling  

Microsoft Academic Search

The authors fabricated optoelectronic wafer probes with both free-space and fiber-optic input, and they adapted microwave error correction techniques to allow calibrated measurements with the new probes. Photoconductive switches on the probe tip define stimulus pulses and sampling intervals, and signals are transferred to and from the wafer under test by coplanar waveguide transmission lines and plated contact bumps. Vector

M. D. Feuer; S. C. Shunk; P. R. Smith; M. C. Nuss; N. H. Law

1993-01-01

421

On the cell probe complexity of membership and perfect hashing  

Microsoft Academic Search

We study two fundamental static data structure problems, membership and perfect hashing, in Yao's cell probe model. The first space and bit probe optimal worst case upper bound is given for the membership problem. We also give a new efficient membership scheme where the query algorithm makes just one adaptive choice, and probes a total of three words. A lower

Rasmus Pagh

2001-01-01

422

Loops in twistor space  

SciTech Connect

We elucidate the one-loop twistor-space structure corresponding to momentum-space maximally helicity-violating diagrams. We also discuss the infrared divergences, and argue that only a limited set of maximally helicity-violating diagrams contain them. We show how to introduce a twistor-space regulator corresponding to dimensional regularization for the infrared-divergent diagrams. We also evaluate explicitly the 'holomorphic anomaly' pointed out by Cachazo, Svrcek, and Witten, and use the result to define modified differential operators which can be used to probe the twistor-space structure of one-loop amplitudes.

Bena, Iosif; Bern, Zvi; Kosower, David A.; Roiban, Radu [Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547 (United States); Service de Physique Theorique, CEA-Saclay F-91191 Gif-sur-Yvette cedex (France); Department of Physics, University of California, Santa Barbara, California 93106 (United States) and Department of Physics, Princeton University, Princeton, New Jersey 08544 (United States)

2005-05-15

423

Planetary Landers and Entry Probes  

NASA Astrophysics Data System (ADS)

Preface; Acknowledgements; Part I. Engineering Issues Specific to Entry Probes, Landers or Penetrators: 1. Mission goals and system engineering; 2. Accommodation, launch, cruise and arrival from orbit or interplanetary trajectory; 3. Entering atmospheres; 4. Descent through an atmosphere; 5. Descent to an airless body; 6. Planetary balloons, aircraft, submarines and cryobots; 7. Arrival at a surface; 8. Thermal control of landers and entry probes; 9. Power systems; 10. Communication and tracking of entry probes; 11. Radiation environment; 12. Surface activities: arms, drills, moles and mobility; 13. Structures; 14. Contamination of spacecraft and planets; Part II. Previous Atmosphere/Surface Vehicles and Their Payloads: 15. Destructive impact probes; 16. Atmospheric entry probes; 17. Pod landers; 18. Legged landers; 19. Payload delivery penetrators; 20. Small body surface missions; Part III. 'Case Studies': 21. Surveyor landers; 22. Galileo probe; 23. Huygens; 24. Mars Pathfinder and Sojourner; 25. Deep Space 2 Mars microprobes; 26. Rosetta lander Philae; 27. Mars exploration rovers: Spirit and Opportunity; Appendix: Some key parameters for bodies in the Solar System; List of acronyms; Bibliography; References; Index.

Ball, Andrew; Garry, James; Lorenz, Ralph; Kerzhanovich, Viktor

2010-02-01

424

Planetary Landers and Entry Probes  

NASA Astrophysics Data System (ADS)

Preface; Acknowledgements; Part I. Engineering Issues Specific to Entry Probes, Landers or Penetrators: 1. Mission goals and system engineering; 2. Accommodation, launch, cruise and arrival from orbit or interplanetary trajectory; 3. Entering atmospheres; 4. Descent through an atmosphere; 5. Descent to an airless body; 6. Planetary balloons, aircraft, submarines and cryobots; 7. Arrival at a surface; 8. Thermal control of landers and entry probes; 9. Power systems; 10. Communication and tracking of entry probes; 11. Radiation environment; 12. Surface activities: arms, drills, moles and mobility; 13. Structures; 14. Contamination of spacecraft and planets; Part II. Previous Atmosphere/Surface Vehicles and Their Payloads: 15. Destructive impact probes; 16. Atmospheric entry probes; 17. Pod landers; 18. Legged landers; 19. Payload delivery penetrators; 20. Small body surface missions; Part III. 'Case Studies': 21. Surveyor landers; 22. Galileo probe; 23. Huygens; 24. Mars Pathfinder and Sojourner; 25. Deep Space 2 Mars microprobes; 26. Rosetta lander Philae; 27. Mars exploration rovers: Spirit and Opportunity; Appendix: Some key parameters for bodies in the Solar System; List of acronyms; Bibliography; References; Index.

Ball, Andrew J.; Garry, James R. C.; Lorenz, Ralph D.; Kerzhanovich, Viktor V.

2007-05-01

425

Voyager 2 Signatures of Important Processes/Dynamics in the Outer Heliosphere  

NASA Astrophysics Data System (ADS)

We continue investigating the Voyager 2 (V2) Plasma Subsystem (PLS) elevated readings in L-mode on energy/unit charge (E/Q) step 12 on the B-Cup we first reported (Intriligator et al., JGR, 2010) near the termination shock at 84 AU. These elevated B12 readings, which we previously referred to as "high energy ions (HEIs)", are found in the V2 PLS data on the sunward facing B-Cup at E/Q step 12 corresponding to 1610 volts and a proton speed of ~ 600 km/s. In the present paper we update our findings and present V2 data from three years earlier when V2 was in the solar wind in the outer heliosphere (OH) at 73 AU measuring the interplanetary (IP) effects from the October-November (Halloween) 2003 solar events. We also examine other V2 OH time intervals. We show links between solar activity and the elevated B12 readings in the V2 data. We present evidence that these elevated B12 readings appear to be accompanied by significant simultaneous changes in other V2 measurements, including: low energy ions, low energy cosmic rays, anomalous cosmic rays, cosmic ray electrons, interplanetary magnetic field (IMF), and convective solar wind plasma. Our results suggest that the V2 elevated B12 readings may be signatures, tracers, by-products, or indicators of important IP processes such as those associated with intervals of particle acceleration, changes in IMF turbulence, and perhaps local reconnection. This work was funded by NASA Grant NNX08AE40G and by Carmel Research Center, Inc.

Intriligator, D. S.; Intriligator, J.; Miller, W. D.; Webber, W. R.; Decker, R. B.; Sittler, E. C.

2011-12-01

426

Analysis of Voyager observed high-energy electron fluxes in the heliosheath using MHD simulations  

NASA Astrophysics Data System (ADS)

The Voyager spacecraft (V1 and V2) observed electrons of 6-14 MeV in the heliosheath which showed several incidences of flux variation relative to a background of gradually increasing flux with distance from the Sun. The increasing flux of background electrons is thought to result from inward radial diffusion. We compare the temporal electron flux variation with dynamical phenomena in the heliosheath that are obtained from our MHD simulations. Because our simulation is based on V2 observed solar-wind data before V2 crossed the termination shock, this analysis is effective up to late 2008, i.e., about a year after the V2-crossing, during which disturbances, driven prior to the crossing time, survived in the heliosheath. Several electron flux variations correspond to times directly associated with interplanetary shock events. One noteworthy example corresponds to various times associated with the March 2006 interplanetary shock, these being the collision with the termination shock, the passage past the V1 spacecraft, and the collision with the region near the heliopause, as identified by W.R. Webber et al. (JGR, 114, A07108, 2009) for proton/helium of 7-200 MeV. Our simulations indicate that all other electron flux variations, except one, correspond well to the times when a shock-driven magneto-sonic pulse and its reflection in the heliosheath either passed across V1/V2, or collided with the termination shock or with the plasma sheet near the heliopause. This result suggests that these variations in the electron flux should be due to either direct or indirect effects of magnetosonic pulses in the heliosheath driven by interplanetary shocks.

Washimi, H.; Webber, W. R.; Zank, G. P.; Hu, Q.; Florinski, V. A.; Adams, J. H.; Kubo, Y.

2011-12-01

427

Survey of low-energy plasma electrons in Saturn's magnetosphere: Voyagers 1 and 2  

SciTech Connect

This paper is a survey of the low-energy plasma electron environment within Saturn's magnetosphere made 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 of distribution functions are clearly non-Maxwellian in character; they are composed of a cold (thermal) component with Maxwellian shape and a hot (suprthermal) non-Maxwellian component. A large-scale positive radial gradient in electron temperature is observed, increasing from less than 1 eV in the inner magnetosphere to as high as 800 eV in the outer magetosphere. This increase in electron temperature explains the observed order of magnitude increase in plasma sheet thickness with increasing radial distance from Saturn. Scale heights of the cold heavy ion plasma can be as small as 0.2 R/sub S/ in the inner magnetosphere and as much as 3 R/sub S/ in the outer magnetosphere. Many of the observed density variations can be attributed to changes in density scale height without a change in plasma flux tube content. Three fundamentally different plasma regimes have been identified from the measurements: (1) the hot outer magnetosphere. (2) the extended plasma sheet, and (3) the inner plasma torus. The hot outer magnetopshere is a region within which the suprathermal electrons are the dominant contributors to the electron pressure, and a times to the electron density. Near the noon meridian, the electrons display a highly time dependent behavior with order of magnitudes changes in density an temperature, which can occur in less than 96 s. Sudden density enhancements of cold plasma occur, which are thought to be either, ''plumes'' associated with Titan (Eviatar et al., 1982) or plasma ''blobs'', (Goertz, 1983).

Sittler, E.C. Jr.; Ogilvie, K.W.; Scudder, J.D.

1983-11-01

428

Audio problems in space  

Microsoft Academic Search

Communication channel capacity is almost invariably at a premium between space vehicles and the earth. In the Apollo moon exploration program, plans call for the use of a special audio processing technique to enhance the signal-to-noise ratio. Extremely deep space probes such as the Mars Mariner IV now use very low bit rate transmissions because of signal-to-noise considerations: future manned

W. Kock

1965-01-01

429

Electric Probes in Plasmas.  

National Technical Information Service (NTIS)

This paper provides a background for the use of Langmuir and gridded energy analyzer probes in diagnosing plasmas with varied characteristics. Theory is illustrated which governs the analysis of data from, and the design of these probes. Several probe ana...

B. Lipschultz I. Hutchinson B. LaBombard A. Wan

1985-01-01

430

Circumferential Pressure Probe.  

National Technical Information Service (NTIS)

A probe for measuring circumferential pressure inside a body cavity is disclosed. In the preferred embodiment, a urodynamic pressure measurement probe for evaluating human urinary sphincter function is disclosed. Along the length of the probe are disposed...

H. K. Holmes T. C. Moore A. J. Fanti

1988-01-01

431

Space station architectural concepts and functional capability  

NASA Astrophysics Data System (ADS)

Space program goals that NASA can best achieve by the construction of a space station in keeping with the 1958 directive to maintain U.S. pre-eminence in space technology are discussed. Science goals that can be satisfied by a suitable equipped space station include a deeper understanding of the earth/sun system and the earth as a planet, the acquisition of new data on the evolution of the solar system, of life, and of the universe, and the extended study of the laws governing the state of matter and energy. Application goals that can be pursued with a space station include assaying all renewable and nonrenewable earth resources, predicting environment, weather, and climatic changes, studying ocean dynamics, using space to develop new processes and materials, and using space for information transmission on a global basis. The space station can serve as a waypoint for voyages by manned or unmanned spacecraft, as a laboratory, observation platform, and technology proving station, and as a base for deployment and repair of other spacecraft.

Herman, D. H.

1983-03-01

432

Soviet space flight: the human element.  

PubMed

Building on past experience and knowledge, the Soviet manned space flight effort has become broad, comprehensive, and forward-looking. Their long-running space station program has provided the capabilities to investigate long-term effects of microgravity on human physiology and behavior and test various countermeasures against microgravity-induced physiological deconditioning. Since the beginning of Soviet manned space flight, the biomedical training and preparation of cosmonauts has evolved from a process that increased human tolerance to space flight factors, to a system of interrelated measures to prepare cosmonauts physically and psychologically to live and work in space. Currently, the Soviet Union is constructing a multimodular space station, the Mir. With the emergence of dedicated laboratory modules, the Soviets have begun the transition from small-scale experimental research to large-scale production activities and specialized scientific work in space. In the future, additional laboratory modules will be added, including one dedicated to biomedical research, called the "Medilab." The longest manned space flight to date (326 days) has been completed by the Soviets. The biomedical effects of previous long-duration flights, and perhaps those of still greater length, may contribute important insight ito the possibility of extended missions beyond Earth, such as a voyage to Mars. PMID:11589234

Garshnek, V

1988-05-01

433

Soviet space flight: the human element.  

PubMed

Building on past experience and knowledge, the Soviet manned space flight effort has become broad, comprehensive, and forward-looking. Their long-running space station program has provided the capabilities to investigate long-term effects of microgravity on human physiology and behavior, and test various countermeasures against microgravity-induced physiological deconditioning. Since the beginning of Soviet manned space flight, the biomedical training and preparation of cosmonauts has evolved from a process that increased human tolerance to space flight factors, to a system of interrelated measures to prepare cosmonauts physically and psychologically to live and work in space. Currently, the Soviet Union is constructing a multimodular space station, the Mir. With the emergence of dedicated laboratory modules, the Soviets have begun the transition from small-scale experimental research to large-scale production activities and specialized scientific work in space. In the future, additional laboratory modules will be added, including one dedicated to biomedical research, called the "Medilab." The longest manned space flight to date (326 d) has been completed by the Soviets. The biomedical effects of previous long-duration flights, and perhaps those of still greater length, may contribute important insight into the possibility of extended missions beyond Earth, such as a voyage to Mars. PMID:2764853

Garshnek, V

1989-07-01

434

Large-scale interplanetary magnetic fields: Voyager 1 and 2 observations between 1 AU and 9. 5 AU  

SciTech Connect

The large-scale radial and temporal variations of the interplanetary magnetic field strength B observed by Voyagers 1 and 2 are discussed. Two components of the magnetic field strength were considered: (1) an average component, B sub zero, based on solar rotation averages, and (2) a fluctuation component, delta B, expressed by 10- or 24-hour averages of B normalized by the best-fit average field for the corresponding time and distance. Observations of the sector structure, interfaces, and shocks are presented to further describe magnetic field strength.

Burlaga, L.F.; Klein, L.W.; Lepping, R.P.; Behannon, K.W.

1984-04-01

435

Lick Saturn-Voyager reference star catalogue (Klemola, Taraji, and Ocampo 1979): Documentation for the machine-readable version  

NASA Astrophysics Data System (ADS)

The machine readable version of the catalog, as it is currently being distributed from the Astronomical Data Center, is described. The catalog contains accurate equatorial coordinates for 4551 stars in a band of sky against which cameras of the Voyager spacecraft were pointed for observations in the region of Saturn during the flyby. All of the reference stars are in the range 12h 40m to 14h 12m in right ascension (1950) and +02 to -09 degs in declination. Mean errors of the positions are about 0.25 sec.

Warren, Wayne H., Jr.

1990-02-01

436

Wilkinson Microwave Anisotropy Probe  

NASA Astrophysics Data System (ADS)

The Wilkinson Microwave Anisotropy Probe (WMAP) is a NASA space mission that has put fundamental theories of the nature of the universe to a precise test. Since August 2001, WMAP has continually surveyed the full sky, mapping out tiny differences in the temperature of the cosmic microwave background (CMB) radiation, which is the radiant heat from the Big Bang. A fossil remnant of the hot big bang, the CMB permeates the universe and is seen today with an average temperature of only 2.725 Kelvin. Tiny variations about this average temperature were first discovered by NASA's Cosmic Background Explorer (COBE) mission. WMAP followed up on the COBE results by characterizing the detailed statistical nature of the CMB temperature variations (called "anisotropy"), revealing a wealth of detail about the global properties of the universe.

Bennett, Charles L.

2005-10-01

437

SP-100 space subsystems development progress  

NASA Astrophysics Data System (ADS)

The space technology effort related to SP-100 subsystems is described in terms of the areas of primary focus and most significant progress. The SP-100 is briefly compared to the Voyager, and detailed descriptions of the converter subsystem, the heat-transport system, and the heat-rejection subsystem. Progress on the converter subsystem includes a high-voltage insulator composed of a single sapphire crystal, a compliant pad of coated niobium, an SiGe thermoelectric (TE) module, and a TE cell assembly. The test of the Nb1Zr piping related to the heat-transport subsystem is described, and the development is reported for the TEM pump and the gas separator. It is concluded that the critical technical issues related to the technologies have been addressed although further efforts are required. Future testing is described for the three major components of the space subsystems including the converter, pump, and the radiator.

Mondt, Jack F.

1991-09-01

438

Great SEP events and space weather, 5. Expected radiation hazard for space probes in space at different distances from the Sun, for satellites in the Earth's magnetosphere at different orbits, for airplanes at different air-lines, and on the ground in dependence of altitude and cutoff rigidity  

Microsoft Academic Search

In report Applbaum et al. (2010) was described how works automatically the program allowed by using one minute data of NM and satellite data for different moments of time to determine time of ejection, diffusion coefficient in the interplanetary space and energy spectrum in source of SEP . These results were obtained for extended interval of solar CR energy, to

Lev Dorman; David Applbaum; Lev Pustil'Nik; Abraham Sternlieb; Alexander Zagnetko; Igor Zukerman

2010-01-01

439

The Voyagers in the 3-D Heliosheath: Transition in Intensities, Flows, and Velocities  

NASA Astrophysics Data System (ADS)

The Voyager 1 (V1) and 2 (V2) spacecraft have been traversing the heliosheath since 2004 (V1) and 2007 (V2), after crossing the termination shock (TS) at distances (latitudes) of 94 AU (34°) and 84 AU (- 29°), respectively. They are currently located at 120 AU (34.5°) and 98 AU (29.5°). The Low Energy Charged Particle (LECP) instrument's measurements of the intensity spectra and the angular distribution of energetic ions (~ 30 keV 40 keV) at V1 decreased by a factor of 2, suggesting that the spacecraft may be approaching the heliopause. Similar decreases in intensity, however, were also seen a month earlier at V2 some ~ 130 AU away, indicating that there may be a global reordering of heliospheric structure connected with the onset of the new solar cycle. V2 intensities recovered after ~6 months, while more recently, intensities at V1 are increasing again. At V2 the intensities of Anomalous Cosmic Rays (ACR) have now increased for the first time to levels even higher than those seen at V1, and substantially higher than they were at the crossing of the TS. Overall, the outer heliosheath appears to be surprisingly diverse and dynamic, and those variations may well reflect a closer connection to the magnetic configuration of the solar corona than thought possible heretofore.

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

2012-04-01

440

Single Particle Laser Ablation Time-of-flight Mass Spectrometer: Maiden Voyage to Houston, TX.  

NASA Astrophysics Data System (ADS)

BNL Single Particle Laser Ablation Time-of-flight Mass Spectrometer (SPLAT-MS) was designed for in-situ characterization of the size and composition of individual aerosols. The aerodynamic lens serves as the sampling inlet. It focuses over 90 percent of entrained particles in the 50nm to 1000nm size range into a well-defined beam of less than 1mm diameter with very low divergence. Two stages of optical detection are used to indicate the presence of particles larger than 50nm and for velocity/size determination. The ablation laser is fired synchronously with the particle's arrival at the inlet to the TOF-MS, it ablates the particle producing ionic fragments for mass spectroscopic analysis by a reflectron time-of-flight mass spectrometer. The resolution of the instrument in mass-to-charge units is 1000. The TOF-MS spectra are digitized at a rate of 500 MHz, and data is transferred to the computer. A very rapid transfer rate of 100 MB/sec allows for high-resolution mass analysis of 20 particles per second. The instrument was deployed for its maiden voyage during the Texas 2000 Air Quality Study in Houston, TX, where it was located on a tall building (300m) near the west of the Houston city center. Over 230,000 particles in size range from 50nm to 3500nm were detected, sized and their composition characterized. Preliminary results of data analysis and visualization will be presented in the context of the overall TX 2000 field campaign. So far 25 particle classes and subclasses were identified and examined based on multivariate binary classification of the TX 2000 data set. The data indicate that the two most abundant types of particles in Houston, TX were sulfate and organic containing particles and that most often these two very broad classes overlap, since many of the sulfate particles were internally mixed with organics. High instrument sampling rate of approximately 2 particles per seconds and the developed visualization and analysis tools allow for an explorations of the data with high resolution in time, size and class, which will be illustrated on the example of the power plant plume episode.

Imre, D. G.; Zelenyuk, A.

2001-12-01

441

Energetic Proton and Electron Distributions in Saturn Magnetosphere as Revealed by Cassini / Voyager Observations and Proposed by Models  

NASA Astrophysics Data System (ADS)

Before the arrival of Cassini at Saturn in July 2004, our knowledge of energetic protons and electrons (energy > 10 KeV) in Saturn's magnetosphere, radial distances r < 12 Rs was mainly based on the particle observations made during the flybys of Pioneer 11 (September 1979), Voyager 1 (November 1980), and Voyager 2 (August 1981). Models of radiation belts have then been developed from direct processes of particles data (LECP) (empirical model) or from physical models drawn on the adiabatic invariant theory and the resolution of the governing Fokker-Planck transport equation. These models have been used to increase our understanding of Saturn radiation belt dynamics, and to predict Cassini observations of particle fluxes (MIMI/LEMMS instrument) and energetic neutral atom emissions (MIMI/INCA instrument). The measurements obtained during the insertion of Cassini at Saturn displayed important differences between predictions and observations. Furthermore, an unexpected new radiation belt in the innermost part of the magnetosphere has been discovered. These new observations have demonstrated that Cassini will provide important new knowledge of Saturn's magnetosphere and revisions of models will need to be considered. We present a preliminary update to our model based on recent LEMMS data. We will discuss both the differences between LEMMS observations and predictions, and the changes made in our model (plasma injection, physical processes, magnetic field model, etc.) in order to reproduce the recent Cassini observations.

Bolton, S. J.; Santos-Costa, D.; Krupp, N.; Dougherty, M.; Roelof, E.; Mitchell, D. G.; Thorne, R. M.; Blanc, M.

2004-12-01

442

Dust distribution around Neptune: Grain impacts near the ring plane measured by the Voyager Planetary Radio Astronomy Experiment  

NASA Astrophysics Data System (ADS)

During the Voyager 2 flyby of Neptune the planetary radio astronomy (PRA) experiment recorded an intense noise near the equatorial plane around 3.4 and 4.2 RN, as already observed during previous Voyager ring plane crossings at Saturn and Uranus. This noise is interpreted as being due to impact ionization of dust grains striking the spacecraft. We deduce a power law index of the grain mass distribution of about 2. The PRA system is sensitive to particles with radii larger than ˜1.6 ?m, and the largest particles, detected near the ring plane, are evaluated to have a radius of ˜10 ?m. The spatial dust distribution along the spacecraft trajectory around the two equatorial crossings is found not to be symmetrical with respect to the ring plane and spread over wide regions: over ˜2 RN perpendicularly to the equatorial plane with the densest part concentrated within ˜700 km. The vertical optical depth ? of this dense region is found to be 10-6 - 10-8.

Pedersen, B. M.; Meyer-Vernet, N.; Aubier, M. G.; Zarka, P.

443

Dust distribution around Neptune - Grain impacts near the ring plane measured by the Voyager planetary radio astronomy experiment  

NASA Astrophysics Data System (ADS)

During the Voyager 2 flyby of Neptune, the planetary radio astronomy (PRA) experiment recorded an intense noise near the equatorial plane around 3.4 and 4.2 R(N), as already observed during previous Voyager ring plane crossings at Saturn and Uranus. This noise is interpreted as being due to impact ionization of dust grains striking the spacecraft. A power law index of the grain mass distribution of about 2 is deduced. The PRA system is sensitive to particles with radii larger than about 1.6 micron, and the largest particles, detected near the ring plane, are evaluated to have a radius of about 10 microns. The spatial dust distribution along the spacecraft trajectory around the two equatorial crossings is found not to be symmetrical with respect to the ring plane and spread over wide regions: over about 2 R(N) perpendicularly to the equatorial plane with the densest part concentrated within about 700 km. The vertical optical depth of this dense region is found to be 10 exp -6 to 10 exp -8.

Pedersen, B. M.; Meyer-Vernet, N.; Aubier, M. G.; Zarka, P.

1991-10-01

444

How probes work  

Microsoft Academic Search

'Cultural probes', since first being proposed and described by Bill Gaver and his colleagues, have been adapted and appropriated for a range of purposes within a variety of technology projects. In this paper we critically review different uses of Probes and discuss common aspects of different Probe variants. We also present and critique some of the debate around Probes through

Connor Graham; Mark Rouncefield; Martin R. Gibbs; Frank Vetere; Keith Cheverst

2007-01-01

445

Neutron-based portable drug probe  

SciTech Connect

Based on previous measurements, a probe prototype for contraband detection utilizing the neutron technique of Pulsed Fast-Thermal Neutron Analysis (PFTNA) is being constructed. The prototype weighs less than 45 kg and is composed of a probe (5 cm diameter), a power pack and a data acquisition and display system. The probe is designed to be inserted in confined spaces such as the boiler of a ship or a tanker truck filled with liquid. The probe provides information on a) the elemental content, and b) the density variations of the interrogated object. By measuring elemental content, the probe can differentiate between innocuous materials and drugs. Density variations can be found through fast neutron transmission. In all cases, hidden drugs are identified through the measurement of the elemental content of the object, and the comparison of expected and measured elemental ratios.

Womble, P. C.; Vourvopoulos, G.; Ball Howard, J.; Paschal, J. [Applied Physics Institute, Western Kentucky University, Bowling Green, Kentucky 42101 (United States)

1999-06-10

446

Hydrodynamic ultrasonic probe  

DOEpatents

An improved probe for in-service ultrasonic inspection of long lengths of a workpiece, such as small diameter tubing from the interior. The improved probe utilizes a conventional transducer or transducers configured to inspect the tubing for flaws and/or wall thickness variations. The probe utilizes a hydraulic technique, in place of the conventional mechanical guides or bushings, which allows the probe to move rectilinearly or rotationally while preventing cocking thereof in the tube and provides damping vibration of the probe. The probe thus has lower friction and higher inspection speed than presently known probes.

Day, Robert A. (Livermore, CA); Conti, Armond E. (San Jose, CA)

1980-01-01

447

Laser probing of the upper waters of the Atlantic and seas around Europe  

NASA Astrophysics Data System (ADS)

The task of investigation of distribution in upper ocean waters of light absorbing and light scattering admixtures is of great interest for oceanology and, specifically, for appreciation of ecological state of sea waters and their contamination of human matters, first of all, by oil products. Among different measuring methods there are especially perspective ones -- methods of sea laser probing from ship's side without stopping of the ship, which allow to make 'simultaneous measures' in quite different voyages -- tourist, cargo, research cruises and etc. Measures (which did not request stopping of the ship), accompanied by taking of probes during motion for subsequent laboratory analyses were organized in the 53 cruise of R/V 'Akademik Kurchatov' around European continent (1994). The works of such type were executed also in the 26 cruise of R/V 'Vityaz' in Atlantic ocean (1991).

Pelevin, Vadim N.; Abramov, O. I.; Carlsen, G. G.; Pelevin, V. V.; Stogov, A. M.; Khlebnikov, D. V.

2000-12-01