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1

Voyager.  

National Technical Information Service (NTIS)

This film documents the flight of the Voyager Saturn. Voyager gives us the first close-up photos of Jupiter and Saturn, and their moons. This is an extremely informative film for all science students, especially astronomers and geologists.

1994-01-01

2

Voyager.  

National Technical Information Service (NTIS)

This program documents the flight of the Voyager Saturn. Voyager gives us the first close-up photos of Jupiter and Saturn, and their moons. This is an extremely informative film for all science students, especially astronomers and geologists.

1994-01-01

3

Voyager.  

ERIC Educational Resources Information Center

This paper provides an overview of the Voyager Expanded Learning programs. Initially begun with hands-on, activity-based learning experiences centered around academic themes designed to pique children's interest and motivate them to learn, Voyager has expanded from elementary after- and summer-school programs to include K-8 programs designed for…

Education Commission of the States, Denver, CO.

4

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

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

5

Voyager at the Edge of Interstellar Space (Invited)  

NASA Astrophysics Data System (ADS)

On August 25, 2012, Voyager 1 entered a region at the outer boundary of the heliosphere in which the low energy ions and anomalous cosmic rays from inside the heliosphere have disappeared and low energy galactic cosmic ray nuclei from outside are present. However, there is a significant pitch angle anisotropy in the cosmic ray intensity that varies, and the direction of the magnetic field remains that of the spiral field in the heliosheath, even though much stronger and less turbulent than previously observed. An overview of these and other new aspects of this region will be presented.

Stone, E. C.

2013-12-01

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

Communicating with Voyager  

NASA Technical Reports Server (NTRS)

The Deep Space Network for receiving Voyager 2 data is discussed. The functions of the earth-Voyager radio link are examined, including radiometrics, transmission of commands to the spacecraft, radio sciences, and the transmission of telemetry from the spacecraft to earth. The use of ranging, Doppler, and VLBI measurements to maintain position and velocity data on Voyager 2 is described. Emphasis is placed on the international tracking network for obtaining Voyager 2 data on Neptune and Triton.

Dumas, Larry N.; Hornstein, Robert M.

1990-01-01

8

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

SciTech Connect

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

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

2013-10-20

9

Impact of Recent Voyager, IBEX, and Cassini Results on Science and Strategy for an Interstellar Probe Mission  

NASA Astrophysics Data System (ADS)

The ongoing Voyager Interstellar Mission (VIM) and recent observations from the Interstellar Boundary Explorer (IBEX) and Cassini missions have revealed the interaction of the heliosphere with the very local interstellar medium (VLISM) to be much more complex than heretofore assumed by our present day concepts. These discoveries call for a major revision of the strategy for the Interstellar Probe mission. With new observations have come significant new puzzles for describing the interaction physics. Direct measurements of the shocked, solar-wind flow speed obtained from Voyager 2 show the flow remains supersonic. Other in situ instruments on Voyager 1 and Voyager 2 continue to reveal significant fluxes of energetic particles in the heliosheath while pointing to a more remote location for the modulation region and source of the anomalous cosmic rays (ACRs). This evidence supports the idea that the bulk of the energy density in the plasma resides in a non-thermal component that extends to very high energies. There are both quantitative and qualitative implications for the overall heliospheric structure. Remote observations by IBEX and the Ion and Neutral Camera (INCA) on Cassini of energetic neutral atoms (ENAs) originating from the interaction region(s) of the solar wind and the VLISM show unexpected structure on a variety of scales. In addition to the general “glow” of the sky in ENAs, IBEX data show a relatively narrow “ribbon” of atomic hydrogen emission from ~200 eV to ~6 keV, roughly circular, but asymmetric in intensity, which may be ordered by the interstellar magnetic field. It passes through, rather than being centered on, the “nose” from which the local, neutral interstellar wind enters the heliosphere, suggesting that the flow is not the primary driver of the system as has been thought. The neutrals from both the glow and ribbon are also characterized by non-thermal distribution functions. INCA on Cassini sees a “belt” of emission in ENAs, broader than the ribbon and tilted significantly away from it, at higher energies (10s of keV). These in situ and remote observations emphasize the need for a new generation of measurements to understand the global nature of our Sun’s interaction with the local galactic environment. Only an interstellar probe with modern instruments and measurement requirements better defined by these recent observations can provide the new information required. To provide a sufficiently fast flyout speed from the heliosphere, careful trades must be done taking into account instrument masses, measurement capabilities, and mission scientific requirements.

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

2010-12-01

10

Cryogenic temperature control by means of energy storage materials. [for long space voyages  

NASA Technical Reports Server (NTRS)

An investigation was conducted to study the concept of thermal control by means of physical or chemical reaction heats for applications involving the storage of cryogens during long-term space voyages. The investigation included some preliminary experimental tests of energy storage material (ESM) effectiveness. The materials considered can store and liberate large amounts of thermal energy by means of mechanisms such as sensible heat, heat of fusion, and physical or chemical reaction heat. A differential thermal analysis was utilized in the laboratory tests. Attention is given to the evaluation of cryogenic ESM thermal control concepts, the experimental determination of phase change materials characteristics, and adsorption ESMs. It is found that an ESM shield surrounded by multiple layer insulation provides the best protection for a cryogen store.

Grodzka, P. G.; Picklesimer, E. A.; Connor, L. E.

1977-01-01

11

Exploring the Galaxy using space probes  

Microsoft Academic Search

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

R. Bjørk

12

Exploring the Galaxy using space probes  

Microsoft Academic Search

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

R. Bjørk

2007-01-01

13

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

Microsoft Academic Search

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

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

1992-01-01

14

Optical Tracking of Deep-Space Probes.  

National Technical Information Service (NTIS)

Specular reflection of sunlight from plane mirror surfaces on deep-space probes is sufficiently bright to be detected with large telescopes on Earth. The optical requirements for the reflector surface and the pointing requirements for its orientation are ...

H. B. Liemohn

1968-01-01

15

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

16

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

17

Voyages South  

NASA Astrophysics Data System (ADS)

During the course of my work with the British Antarctic Survey (BAS) I have made several voyages to the Antarctic, travelling on the Royal Research Ship Bransfield and shorter voyages on the RRS James Clark Ross and HMS Endurance. My time at sea and on land has given me many opportunities to view interesting atmospheric and astronomical phenomena of the southern hemisphere.

Shanklin, J. D.

1997-12-01

18

Voyager cartography  

Microsoft Academic Search

The Jovian and Saturnian satellites are being mapped at several scales from Voyager 1 and 2 data. The maps include specially formatted color mosaics, controlled photomosaics, and airbrush maps. More than 500 Voyager images of the Jovian and Saturnian satellites were radiometrically processed in preparation for cartographic processing. Of these images, 235 were geometrically transformed to map projections for base

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

1985-01-01

19

Summary of Voyager Design and Flight Loads.  

National Technical Information Service (NTIS)

Estimates of flight loads for Voyager 1 and Voyager 2 are summarized and compared to the Voyager design loads obtained from the shock spectra/impedance method and to the loads obtained using space vehicle transient loads analysis. These estimates were obt...

F. D. Day J. A. Garba J. C. Chen

1978-01-01

20

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

21

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.

22

Gigapan Voyage for Robotic Recon  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

23

Exploring the Galaxy using space probes  

NASA Astrophysics Data System (ADS)

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 box from -300 to 300 pc above the Galactic thin disc, as a function of Galactic radius. The Galaxy is then modelled to consist of 260000 of these 40000 stellar systems all located in a defined Galactic Habitable Zone and how long a time it takes to explore this zone is shown. The result is that with eight probes, each with eight subprobes, 4% of the Galaxy can be explored in 2.92x10^8 years. Increasing the number of probes to 200, still with eight subprobes each, reduces the exploration time to 1.52x10^7 years.

Bjørk, R.

2007-04-01

24

Employment of Asteroids for Movement Space Ship and Probes  

NASA Technical Reports Server (NTRS)

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

Bolonkin, Alexander

2002-01-01

25

Perspectives on More Than 3 Decades of the Voyager Mission  

NASA Astrophysics Data System (ADS)

Voyager 1 and Voyager 2, twin NASA probes that were launched from Cape Canaveral, Fla., in the summer of 1977 during a once-every-175-year alignment of the solar system's giant outer planets, changed our understanding about those planets—Jupiter, Saturn, Uranus, and Neptune—as well as the 4 dozen moons the spacecraft have flown by and the shape of the solar system itself. Today these 722-kilogram probes, whose instruments mostly are still operating after almost 34 years in space, are helping to rewrite the textbooks about the outer edge of our solar system as they continue to race outward from Earth. Voyager 1, currently 17.4 billion kilometers from Earth, and Voyager 2, 14.2 billion kilometers from Earth, are on their way to becoming the first human-made objects to leave the solar system and enter interstellar space, the medium between stars. In exclusive interviews with Eos and during a 27 April news briefing at NASA headquarters in Washington, D. C., Voyager project scientist Ed Stone and several others who have worked on the project discussed mission highlights and the probes' journeys through the heliosheath. This is the final outer layer of a kind of bubble the Sun creates around itself called the heliosphere, a margin where the solar wind is slowed by the pressure of interstellar gas. All the while, the spacecraft, still responsive to ground commands, are sending back data about the solar wind, the magnetic field carried out by the wind, charged particles, and plasma waves.

Showstack, Randy

2011-05-01

26

Voyager picture of Jupiter  

NASA Technical Reports Server (NTRS)

NASA's Voyager 1 took this picture of the planet Jupiter on Saturday, Jan. 6, the first in its three-month-long, close-up investigation of the largest planet. The spacecraft, flying toward a March 5 closest approach, was 35.8 million miles (57.6 million kilometers) from Jupiter and 371.7 million miles (598.2 million kilometers) from Earth when the picture was taken. As the Voyager cameras begin their meteorological surveillance of Jupiter, they reveal a dynamic atmosphere with more convective structure than had previously been thought. While the smallest atmospheric features seen in this picture are still as large as 600 miles (1,000 kilometers) across, Voyager will be able to detect individual storm systems as small as 3 miles (5 kilometers) at closest approach. The Great Red Spot can be seen near the limb at the far right. Most of the other features are too small to be seen in terrestrial telescopes. This picture was transmitted to the Jet Propulsion Laboratory through the Deep Space Network's tracking station at Madrid, Spain. The Voyager Project is managed for NASA by Caltech's Jet Propulsion Laboratory.

1998-01-01

27

Voyager cartography  

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

28

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.

29

Thermodynamic considerations in the support of life for long space voyages  

NASA Technical Reports Server (NTRS)

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

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

1979-01-01

30

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

31

Summary of Voyager design and flight loads  

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

32

The Voyager Neptune travel guide  

NASA Technical Reports Server (NTRS)

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

Kohlhase, Charles (editor)

1989-01-01

33

NASA Facts: Voyager  

NASA Technical Reports Server (NTRS)

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

1977-01-01

34

The Voyager Interstellar Mission.  

PubMed

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

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

1997-01-01

35

The Voyager Interstellar Mission  

NASA Technical Reports Server (NTRS)

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

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

1997-01-01

36

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

37

Energetic Particle Events (> or =30 keV) of Jovian origin observed by Voyager 1 and 2 in interplanetary space  

Microsoft Academic Search

Short-lived and long-lived ion flux increases (E> or =30 keV) of Jovian origin have been observed by the low energy charged particle (LECP) instrumnet on the Voyager 1 and 2 spacecraft. The short-lived events are observed more than 860 R\\/sub J\\/ upstream and more than 1500 R\\/sub J\\/ downstream of Jupiter. Observations of long-lived events appear to be confined to

R. D. Zwickl; S. M. Krimigis; J. F. Carbary; E. P. Keath; T. P. Armstrong; D. C. Hamilton; G. Gloeckler

1981-01-01

38

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

39

Voyager cartography  

NASA Technical Reports Server (NTRS)

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

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

1987-01-01

40

Voyager - Humanity's Farthest Journey  

NASA Video Gallery

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

41

Surface and Subsurface Quadrupolar Probes for Future Space Missions  

Microsoft Academic Search

Quadrupolar Probes (also called Mutual Impedance Probes) can accurately measure the electrical properties of gaseous, solid and liquid materials. Flight instruments have been developed for atmospheric investigations (Huygens) and for stationary surface measurements (Rosetta lander). Future space missions will employ mobile platforms such as surface vehicles and underground tools (drills, moles). These new instrument carriers will require adapted electrode configurations

R. Trautner; F. Simões; R. Grard; M. Hamelin

2003-01-01

42

Voyager Program: Voyager 2 Encounter at Saturn.  

National Technical Information Service (NTIS)

The planned sequence of events for the encounter are presented. The current status of the Voyager flight and ground systems, and the mission success criteria are summarized. Key Voyager team members are identified. Changes to the plan described may be exp...

1981-01-01

43

Voyager's Last Encounter  

NASA Technical Reports Server (NTRS)

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

1989-01-01

44

The grandest tour - Voyager  

Microsoft Academic Search

The Voyager mission based on two spacecraft, Voyager 1 and Voyager 2, launched on September 5, 1977 and August 20 1977, respectively, is reviewed. The mission was designed to take advantage of a rare geometric arrangement of Jupiter, Saturn, Uranus, and Neptune that occurs only once every 176 years. Particular attention is given to data on Jupiter's ring and moons,

Mary B. Murrill

1993-01-01

45

The Quantitative Operational Space for Three-dimensional Atom Probes  

Microsoft Academic Search

The operational space for quantitative analysis of a range of materials has been investigated with local electrode atom probe equipped with a high pulse repetition rate voltage pulse generator and a ultrafast pulsed laser. This operating space has been explored with the following systems: a binary alloy composed of elements with dramatically different evaporations fields; a material with a single

M. K. Miller; D. J. Larson; J. D. Olson; S. L. P. Kostrna; R. W. O'Neil; B. Geiser; E. Oltman

2006-01-01

46

Voyager-Jupiter radio science data papers  

NASA Technical Reports Server (NTRS)

The reduction and interpretation of the radio science data from the Voyager 1 and 2 encounters of the planet Jupiter and its satellites resulted in the preparation of several papers for publication in the special Voyager-Jupiter issue of the Journal of Geophysical Research. The radio science and tracking systems of the Deep Space Network provide the data which makes this research possible. This article lists submitted papers by title, with their authors and with abstracts of their contents.

Levy, G. S.; Wood, G. E.

1980-01-01

47

How Do Probes Get To Space?  

NSDL National Science Digital Library

Investigate how force and thrust work to propel rockets into outer space. Build a rocket: a blown-up balloon taped to a drinking straw threaded through some string. The rocket follows Newton's Third Law of Motion: Every action produces an equal and opposite reaction.

Science, Jason

1999-01-01

48

Space-charge limits of ion sensitive probes  

NASA Astrophysics Data System (ADS)

Ion sensitive probes (ISPs) are used to measure ion temperature and plasma potential in magnetized plasmas. Their operation relies on the difference in electron and ion Larmor radii to preferentially collect the ion species on a recessed electrode. Because of their simple two-electrode construction and optimal geometry for heat flux handling they are an attractive probe to use in the high heat flux boundary of magnetic confinement fusion experiments. However, the integrity of its measurements is rarely, if ever, checked under such conditions. Recent measurements with an ISP in the Alcator C-Mod tokamak have shown that its ion current is space-charge limited and thus its current-voltage (I-V) response does not contain information on the ion temperature. We numerically solve a 1D Vlasov-Poisson model of ion collection to determine how much bias is needed to overcome space-charge effects and regain the classic I-V characteristic with an exponential decay. Prompted by the observations of space charge in C-Mod, we have performed a survey of ISP measurements reported in the literature. Evidence of space-charge limited current collection is found on many probes, with few authors noting its presence. Some probes are able to apparently exceed the classic 1D space-charge limit because electrons can E × B drift into the probe volume, partially reducing the net ion charge; it is argued that this does not, however, change the basic problem that space charge compromises the measurement of ion temperature. Guidance is given for design of ISPs to minimize the effects of space charge.

Brunner, D.; LaBombard, B.; Ochoukov, R.; Sullivan, R.; Whyte, D.

2013-12-01

49

Voyage of Discovery  

NASA Video Gallery

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

50

Voyager at Uranus: 1986  

NASA Technical Reports Server (NTRS)

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

1986-01-01

51

Features of the Gravity Probe B Space Vehicle  

NASA Astrophysics Data System (ADS)

Space vehicle performance enabled successful relativity data collection throughout the Gravity Probe B mission. Precision pointing and drag-free translation control was maintained using proportional helium micro-thrusters. Electrical power was provided by rigid, double sided solar arrays. The 1.8 kelvin science instrument temperature was maintained using the largest cryogenic liquid helium dewar ever flown in space. The flight software successfully performed autonomous operations and safemode protection. Features of the Gravity Probe B Space Vehicle mechanisms include: 1) sixteen helium micro-thrusters, the first proportional thrusters flown in space, and large-orifice thruster isolation valves, 2) seven precision and high-authority mass trim mechanisms, 3) four non-pyrotechnic, highly reliable solar array deployment and release mechanism sets. Early incremental prototyping was used extensively to reduce spacecraft development risk. All spacecraft systems were redundant and provided multiple failure tolerance in critical systems. Lockheed Martin performed the spacecraft design, systems engineering, hardware and software integration, environmental testing and launch base operations, as well as on-orbit operations support for the Gravity Probe B space science experiment.

Reeve, William; Green, Gaylord

2007-04-01

52

This view of Jupiter was taken by Voyager 1  

NASA Technical Reports Server (NTRS)

This view of Jupiter was taken by Voyager 1. This image was taken through color filters and recombined to produce the color image. This photo was assembled from three black and white negatives by the Image Processing Lab at Jet Propulsion Laboratory. JPL manages and controls the VOyager project for NASA's Office of Space Science.

1998-01-01

53

Voyager 1 Image of Ganymede  

NASA Technical Reports Server (NTRS)

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

1979-01-01

54

The grandest tour - Voyager  

NASA Astrophysics Data System (ADS)

The Voyager mission based on two spacecraft, Voyager 1 and Voyager 2, launched on September 5, 1977 and August 20 1977, respectively, is reviewed. The mission was designed to take advantage of a rare geometric arrangement of Jupiter, Saturn, Uranus, and Neptune that occurs only once every 176 years. Particular attention is given to data on Jupiter's ring and moons, the discovery of active volcanoes on Io, Jovian magnetism, Saturn's atmosphere, Titan and other moons, Uranus and Miranda, Uranian moons and rings, Triton's atmosphere.

Murrill, Mary B.

1993-06-01

55

Voyager at Neptune: 1989  

NASA Technical Reports Server (NTRS)

The Voyager mission has taken advantage of a rare planetary alignment that occurs at intervals of about 175 years and affords an extraordinary opportunity: a grand tour by a single spacecraft of the outer planets Jupiter, Saturn, Uranus, and Neptune. Voyager 2 will fly past Nepture and its large moon Triton on August 24, 1989. The discovery of Neptune, along with its current history is discussed. The imaging challenges, tracking and data acquisition, and the Voyager spacecraft are explained. Data will be gathered on the ring arcs of Neptune, the atmosphere and surface of Neptune, Triton, and Nereid (the smaller moon).

1989-01-01

56

Career Voyages - Biotechnology  

NSDL National Science Digital Library

Career voyages offers information about different professional fields within the biotechnology industry. Includes information on manufacturing and production, research and development, quality control and assurance, agriculture, bioprocessing, and bioinformatics.

Career Voyages (USA.gov;)

2008-04-15

57

Voyages to Saturn  

NASA Technical Reports Server (NTRS)

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

Morrison, D.

1982-01-01

58

Artist's Concept of Voyager  

NASA Technical Reports Server (NTRS)

This artist's concept of the Voyager spacecraft with its antenna pointing to Earth. The identical Voyager spacecraft are three-axis stabilized systems that use celestial or gyro referenced attitude control to maintain pointing of the high-gain antennas toward Earth. The prime mission science payload consisted of 10 instruments (11 investigations including radio science). Only five investigator teams are still supported, though data are collected for two additional instruments.

2003-01-01

59

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

PubMed Central

The “small molecule universe” (SMU), the set of all synthetically feasible organic molecules of 500 Daltons molecular weight or less, is estimated to contain over 1060 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.

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

2013-01-01

60

Voyager electronic parts radiation program, volume 1  

NASA Technical Reports Server (NTRS)

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

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

1977-01-01

61

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

62

Gigapan Voyage for Robotic Recon.  

National Technical Information Service (NTIS)

Gigapan Voyage (GV) is a self-contained remotely-operable Gigapan capturing system that is currently being developed by the Intelligent Robotics Group (IRG) at NASA Ames Research Center. Gigapan Voyage was primarily designed to be integrated onto Johnson ...

E. J. Park S. Y. Lee T. F. Moorse

2010-01-01

63

Voyager Observations of Globular Clusters.  

National Technical Information Service (NTIS)

The objectives of this task are to direct and analyze the observations of globular clusters targets observed with the ultraviolet spectrometer on the Voyager spacecraft. The data analysis will be directed toward understanding the Voyager spectra or upper ...

1994-01-01

64

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

65

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

66

Infrared spectrometer for Voyager  

NASA Astrophysics Data System (ADS)

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 is given to the optical layout, the electronics module, power supply placement, thermal control heaters and flash heaters, data reduction, and calibration. A sample spectrum of Jupiter is also discussed.

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

1980-05-01

67

Langmuir Probes for Obstanovka Experiment Aboard the Russian Segment of the International Space Station.  

National Technical Information Service (NTIS)

This report results from a contract tasking Bulgarian Academy of Sciences as follows: The Grantee will investigate the development of Langmuir probes for measuring space plasma. Tasks include: - Integration tests of the Langmuir probes with the Hungarian ...

B. Kirov

2010-01-01

68

Space Audio  

NSDL National Science Digital Library

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

69

Probing Protein Fold Space with a Simplified Model  

PubMed Central

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 (0-300 residues), amino acid composition, and number of secondary structural elements. The degrees of freedom are taken as the loop torsion angles. This choice preserves the native secondary structure but allows the tertiary structure to change. The proteins are represented by three-point per residue, three-dimensional models with statistical potentials derived from a knowledge-based study of known protein structures. When this space is sampled by a combination of Parallel Tempering and Equi-Energy Monte Carlo, we find that the three-point model captures the known stability of protein native structures with stable energy basins that are near-native (all-?: 4.77 Å, all-?: 2.93 Å, ?/?: 3.09 Å, ?+?: 4.89 Å on average and within 6 Å for 71.41 %, 92.85 %, 94.29 % and 64.28 % for all-?, all-?, ?/? and ?+?, classes respectively). Denatured structures also occur and these have interesting structural properties that shed light on the different landscape characteristics of ? and ? folds. We find that ?/? proteins with alternating ? and ? segments (such as the beta-barrel) are more stable than proteins in other fold classes.

Minary, Peter; Levitt, Michael

2008-01-01

70

Voyager 2 at Uranus  

Microsoft Academic Search

The Voyager 2 spacecraft, hurtling toward its January 24, 1986, closest approach to Uranus, is sending several surprises back to earth. One is the discovery of another moon; the other is the absence of expected radio noise at a distance less than 800 times the planet's radius.As Eos went to press, a sixth moon had been discovered orbiting the planet.

Judith A. Katzoff; Barbara T. Richman

1986-01-01

71

Aspects of Voyager photogrammetry  

Microsoft Academic Search

In January 1986, Voyager 2 took a series of pictures of Uranus and its satellites with the Imaging Science System (ISS) on board the spacecraft. Based on six stereo images from the ISS narrow-angle camera, a topographic map was compiled of the Southern Hemisphere of Miranda, one of Uranus' moons. Assuming a spherical figure, a 20-km surface relief is shown

Sherman S. C. Wu; Francis J. Schafer; Raymond Jordan; Annie-Elpis Howington

1987-01-01

72

Aspects of Voyager Photogrammetry.  

National Technical Information Service (NTIS)

In January 1986, Voyager 2 took a series of pictures of Uranus and its satellites with the Imaging Science System (ISS) on board the spacecraft. Based on six stereo images from the ISS narrow-angle camera, a topographic map was compiled of the Southern He...

S. S. C. Wu F. J. Schafer R. Jordan A. Howington

1987-01-01

73

Voyager at Uranus  

NASA Astrophysics Data System (ADS)

The findings made in the Voyager flyby past Uranus are reviewed. The spacecraft is described, and the preparations for the Uranus encounter are recalled. The encounter characteristics are presented, and the characteristics of the Uranian atmosphere and interior, magnetic field, rings, and satellites are discussed.

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

1988-02-01

74

Ocean Voyagers Lesson Plans  

NSDL National Science Digital Library

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

75

Voyager Outreach Compilation  

NASA Technical Reports Server (NTRS)

This NASA JPL (Jet Propulsion Laboratory) video presents a collection of the best videos that have been published of the Voyager mission. Computer animation/simulations comprise the largest portion of the video and include outer planetary magnetic fields, outer planetary lunar surfaces, and the Voyager spacecraft trajectory. Voyager visited the four outer planets: Jupiter, Saturn, Uranus, and Neptune. The video contains some live shots of Jupiter (actual), the Earth's moon (from orbit), Saturn (actual), Neptune (actual) and Uranus (actual), but is mainly comprised of computer animations of these planets and their moons. Some of the individual short videos that are compiled are entitled: The Solar System; Voyage to the Outer Planets; A Tour of the Solar System; and the Neptune Encounter. Computerized simulations of Viewing Neptune from Triton, Diving over Neptune to Meet Triton, and Catching Triton in its Retrograde Orbit are included. Several animations of Neptune's atmosphere, rotation and weather features as well as significant discussion of the planet's natural satellites are also presented.

1998-01-01

76

VOYAGER OBSERVATIONS OF THE DIFFUSE FAR-ULTRAVIOLET RADIATION FIELD  

SciTech Connect

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

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

2012-03-01

77

The Voyager Cosmic Ray Experiment  

NASA Technical Reports Server (NTRS)

The Voyager Cosmic Ray Experiment includes seven dE/dx-E telescopes to measure the energy and charge of particles with atomic numbers from 1 to 26 in the energy range 1-500 MeV/nucleon and to measure electron energy in the range from 3 to 110 MeV. Isotopic composition of hydrogen through sulfur in the range up to 75 Mev/nucleon can also be resolved. The electronic systems include a dual-gain, charge sensitive preamplifier, 4096-channel pulse height analyzers for three parameter analysis of selected events, and an event type readout polling scheme to maximize the use of available telemetry space and to enhance the occurrence of rare events in the data. Details of the detector, electronic and mechanical design are presented.

Stilwell, D. E.; Davis, W. D.; Joyce, R. M.; Mcdonald, F. B.; Trainor, J. H.; Althouse, W. E.; Cummings, A. C.; Garrard, T. L.; Stone, E. C.; Vogt, R. E.

1979-01-01

78

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 investigate the driving forces behind this 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. This project has been developed to be used as a complete tutorial on the Gulf Stream. However, the activities are presented in a manner so that each may be used individually to supplement traditional classroom lessons. Students access real time ocean data, atmospheric data and historical primary source materials. Students utilize these resources, all in the context of an authentic real world problem.

2011-05-31

79

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.

80

Voyager: Giant Kelp  

NSDL National Science Digital Library

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

Criqui, Nan

81

Voyager: The Sheltering Forest  

NSDL National Science Digital Library

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

Criqui, Nan

82

Voyager 1 'Blue Movie'  

NASA Technical Reports Server (NTRS)

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

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

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

2000-01-01

83

Voyager Approaches Final Frontier  

NASA Technical Reports Server (NTRS)

An artist's concept illustrates the positions of the Voyager spacecraft in relation to structures formed around our Sun by the solar wind. Also illustrated is the termination shock, a violent region the spacecraft must pass through before reaching the outer limits of the solar system. At the termination shock, the supersonic solar wind abruptly slows from an average speed of 400 kilometers per second to less than 100 kilometer per second (900,000 to less than 225,000 miles per hour). Beyond the termination shock is the solar system's final frontier, the heliosheath, a vast region where the turbulent and hot solar wind is compressed as it presses outward against the interstellar wind that is beyond the heliopause. A bow shock likely forms as the interstellar wind approaches and is deflected around the heliosphere, forcing it into a teardrop-shaped structure with a long, comet-like tail.

The exact location of the termination shock is unknown, and it originally was thought to be closer to the Sun than Voyager 1 currently is. As Voyager 1 cruised ever farther from the Sun, it confirmed that all the planets are inside an immense bubble blown by the solar wind and the termination shock was much more distant.

2003-01-01

84

Aspects of Voyager photogrammetry  

NASA Astrophysics Data System (ADS)

In January 1986, Voyager 2 took a series of pictures of Uranus and its satellites with the Imaging Science System (ISS) on board the spacecraft. Based on six stereo images from the ISS narrow-angle camera, a topographic map was compiled of the Southern Hemisphere of Miranda, one of Uranus' moons. Assuming a spherical figure, a 20-km surface relief is shown on the map. With three additional images from the ISS wide-angle camera, a control network of Miranda's Southern Hemisphere was established by analytical photogrammetry, producing 88 ground points for the control of multiple-model compilation on the AS-11AM analytical stereoplotter. Digital terrain data from the topographic map of Miranda have also been produced. By combining these data and the image data from the Voyager 2 mission, perspective views or even a movie of the mapped area can be made. The application of these newly developed techniques to Voyager 1 imagery, which includes a few overlapping pictures of Io and Ganymede, permits the compilation of contour maps or topographic profiles of these bodies on the analytical stereoplotters.

Wu, Sherman S. C.; Schafer, Francis J.; Jordan, Raymond; Howington, Annie-Elpis

1987-05-01

85

Aspects of Voyager photogrammetry  

NASA Technical Reports Server (NTRS)

In January 1986, Voyager 2 took a series of pictures of Uranus and its satellites with the Imaging Science System (ISS) on board the spacecraft. Based on six stereo images from the ISS narrow-angle camera, a topographic map was compiled of the Southern Hemisphere of Miranda, one of Uranus' moons. Assuming a spherical figure, a 20-km surface relief is shown on the map. With three additional images from the ISS wide-angle camera, a control network of Miranda's Southern Hemisphere was established by analytical photogrammetry, producing 88 ground points for the control of multiple-model compilation on the AS-11AM analytical stereoplotter. Digital terrain data from the topographic map of Miranda have also been produced. By combining these data and the image data from the Voyager 2 mission, perspective views or even a movie of the mapped area can be made. The application of these newly developed techniques to Voyager 1 imagery, which includes a few overlapping pictures of Io and Ganymede, permits the compilation of contour maps or topographic profiles of these bodies on the analytical stereoplotters.

Wu, Sherman S. C.; Schafer, Francis J.; Jordan, Raymond; Howington, Annie-Elpis

1987-01-01

86

Energetic particle events /greater than or equal to 30 keV/ of Jovian origin observed by Voyager 1 and 2 in interplanetary space  

NASA Technical Reports Server (NTRS)

Detailed observations of ion events of Jovian origin as observed by the low energy charge particle (LECP) instrumentation on Voyager 1 and 2 during the inbound and outbound pass for both spacecraft are reported. The general characteristics of these events are examined, and a comparison is made with similar observations at earth. Careful attention is given to the compositional signature of the Jovian ion events. Two of the specific events discussed in detail are selected to display the range of variability and complexity of the Jovian-produced interplanetary ion events. The observations are seen as strongly implying that the Jovian magnetosphere is the source of a significant fraction of the particles.

Zwickl, R. D.; Krimigis, S. M.; Carbary, J. F.; Keath, E. P.; Armstrong, T. P.; Hamilton, D. C.; Gloeckler, G.

1981-01-01

87

Floating Potential Probe Deployed on the International Space Station  

NASA Technical Reports Server (NTRS)

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

Ferguson, Dale C.

2001-01-01

88

Radial gradient of cosmic ray intensity from a comparative study of data from Voyager 1 and 2 and IMP 8  

NASA Astrophysics Data System (ADS)

The IMP 8 satellite and Voyager 1 and 2 space probes obtained cosmic ray measurements during the late 1977 to mid-1982 period. Comparisons of 27-day averages of the data show that a positive radial intensity gradient existed on the average during this period, and that the cosmic ray intensity decrease toward solar maximum in 1980-1981 proceeds in a stepwise fashion. The cosmic ray minimum reached in late 1980/early 1981 appears almost simultaneously at 1 AU and at 10 AU, with and without propagation time delay effects, between IMP 8 and the Voyager spacecraft. These data are generally consistent with a heliolatitudinal gradient of 0 + or - 1 percent/deg. Attention is given to the implications of these results in the overall context of cosmic ray modulation theory.

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

1984-06-01

89

Erratum: Voyager Color Photometry of Saturn's Main Rings  

NASA Technical Reports Server (NTRS)

We correct a calibration error in our earlier analysis of Voyager color observations of Saturn's main rings at 14 deg phase angle and present thoroughly revised and reanalyzed radial profiles of the brightness of the main rings in Voyager G, V, and UV filters, and ratios of these brightnesses. These results are consistent with more recent HST results at 6 deg phase angle, once allowance is made for plausible phase reddening of the rings. 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 6-14 deg phase angles are hinted at. We update a ring-and-satellite color vs. albedo plot from Cuzzi and Estrada 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.; DeVincenzi, Donald (Technical Monitor)

2002-01-01

90

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

91

Voyage to a blue planet  

Microsoft Academic Search

Preliminary analysis of Voyager 2 data on Uranus and its moons has yielded several surprising results. Here, a brief description is given of the observational data concerning Uranus tilted magnetic field, circulating atmosphere, ring structure, and moons. Emphasis is given to voyager images of the moon Miranda which display a patchwork of sinuous valleys similar to those of Mars. Some

M. M. Waldrop

1986-01-01

92

Deep Space Network capabilities for receiving weak probe signals  

NASA Technical Reports Server (NTRS)

This paper will describe the capability and highlight the cases of the critical communications for the Mars rovers and Saturn Orbit Insertion and preparation radio tracking of the Huygens probe at (non-DSN) radio telescopes.

Asmar, Sami; Johnston, Doug; Preston, Robert

2004-01-01

93

Direct Write Sensors for Space and Probe Applications  

NASA Astrophysics Data System (ADS)

This presentation will summarize the latest advances in Direct Write Thermal Spray technology related to probe applications including temperature sensors, heat flux sensors, recession sensors, integrated wiring, antennas, and heaters.

Greenlaw, R. J.; Arthur, D. T.; Anderson, R. C.; Andrade, J. E.

2014-06-01

94

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

95

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

NASA Technical Reports Server (NTRS)

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

Morton, Thomas L.; Ferguson, Dale C.

2001-01-01

96

Take a Voyage of Discovery  

NSDL National Science Digital Library

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

Texley, Juliana

2008-07-01

97

The Voyager spacecraft system design  

NASA Technical Reports Server (NTRS)

The Voyager spacecraft represents the state-of-the-art in proven long-life planetary spacecraft. Like its predecessors, the Voyager system design reflects the influence of mission and science requirements, lifetime considerations, environmental factors, technology readiness, hardware availability, and hardware cost. This paper presents the Voyager hardware and software system designs within the context of these design drivers. Major departures from the 'baseline design' are discussed revealing the underlying factors that shaped the final design. Finally, with the benefit of 5 years of test and inflight operational experience, a critical assessment of the design and design methods is made and suggestions are offered to improve similar future efforts.

Jones, C. P.; Risa, T. H.

1981-01-01

98

Voyager photometry of Iapetus  

NASA Astrophysics Data System (ADS)

Voyager images of Saturn's satellite Iapetus ranging in phase angle from 8 to 90 deg have been used to define the satellite's photometric properties and construct an albedo map of its surface. Iapetus shows variations in reflectance across its surface of a factor of 10 to 20, the greatest albedo range known for a solar system object. It is darkest at the apex of orbital motion, becomes brighter away from the apex, and is brightest near the poles. The 'boundary' between light and dark material is gradual rather than sharp. The photometric properties of the surface are adequately described by a lunarlike photometric function, but the surface phase function varies with albedo. The dark material on Iapetus is reddish, the bright material somewhat less so.

Squyres, S. W.; Buratti, B.; Veverka, J.; Sagan, C.

1984-09-01

99

Amalthea - Voyager imaging results  

NASA Technical Reports Server (NTRS)

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.

Veverka, J.; Thomas, P.; Davies, M.; Morrison, D.

1981-01-01

100

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

101

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

102

Voyager encounters Saturn: Scientific highlights  

NASA Technical Reports Server (NTRS)

Observations generated by Voyager 1's encounter with Saturn are disclosed. Atmospheric conditions, the rings, new moons and the five inner moons are described. Titan, Hyperion and Iapetus are discussed in detail, as is Saturn's magnetosphere.

1980-01-01

103

Magnetic field studies at Jupiter by Voyager 1: preliminary results  

Microsoft Academic Search

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

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

1979-01-01

104

Enabling interstellar probe  

NASA Astrophysics Data System (ADS)

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

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

2011-04-01

105

Probing chemical space with alkaloid-inspired libraries.  

PubMed

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

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

2014-02-01

106

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

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

107

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

108

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

109

Improved downlink frequency calculations for Voyager 2  

NASA Astrophysics Data System (ADS)

Voyager 2 and her sister Voyager 1 were launched, respectively, in August and September 1977. The object of these spacecraft was to conduct exploratory investigations of the Jupiter and Saturn planetary systems and the interplanetary medium between Earth and Saturn. In April 1978 the Voyager 2 redundant receiver and the loop capacitor in the prime spacecraft receiver failed, leaving the Voyager Project with a major problem: how to communicate with the spacecraft and get the data back.

Ricardo, A. L.

1982-11-01

110

46 CFR 80.15 - Ocean voyage.  

Code of Federal Regulations, 2013 CFR

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

2013-10-01

111

The Voyage of the Beagle  

NSDL National Science Digital Library

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

Darwin, Charles, 1809-1882.

1999-01-01

112

View of Callisto from Voyager and Galileo  

NASA Technical Reports Server (NTRS)

View of Callisto, most distant of the four large moons of Jupiter. This mosaic was prepared from images obtained by three spacecraft: Voyager 1 (left side), Galileo (middle), and Voyager 2 data (right side). The Voyager data were taken in 1979 but left a 'gap' centered at longitude 290 degrees in the trailing hemisphere of Callisto. The Galileo Solid-State Imaging system photographed this area on its second orbit around Jupiter on 9 September, 1996 Universal Time. The resolution of the Galileo data is 4.3 kilometers/pixel (2.7 miles), meaning that the smallest visible feature is about 12 kilometers (7 miles) across. North is to the top of the picture.

Features of interest in the new Galileo data include a dark, smooth area in the northern latitudes (upper third) which appears to mantle older terrain. This could be dark ejecta from a small impact crater. Also visible is a fresh, sharp-rimmed crater some 90 km (56 miles) across named Igaluk (center left third of picture), and a bright zone in the south polar area (bottom of image) which could be an impact scar.

The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

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

1996-01-01

113

MARINER 8 SPACE PROBE UNDERGOES INSTALLATION OF SOLAR ARRAYS  

NASA Technical Reports Server (NTRS)

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

1971-01-01

114

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

115

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

Microsoft Academic Search

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

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

2010-01-01

116

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

NASA Technical Reports Server (NTRS)

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

Hills, H. K.

1984-01-01

117

Voyager to Jupiter and Saturn  

NASA Technical Reports Server (NTRS)

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

1977-01-01

118

Technology Brings Voyagers into Classrooms.  

ERIC Educational Resources Information Center

Three articles focus on many classroom activities and experiments inspired by the voyage of two canoes, built of traditional materials, from Hawaii's Hilo Harbor in 1995. Nationwide, students followed daily satellite tracking, accessed the Internet for updated accounts of the canoes, talked directly with navigators, and watched television…

Inn, Kristina; And Others

1995-01-01

119

A Voyage through the Heliosphere (Invited)  

NASA Astrophysics Data System (ADS)

Parker adopted the word “Heliosphere” to denote “the region of interstellar space swept out by the solar wind” His book “Interplanetary Dynamical Processes” (1963) provided “a comprehensive self-consistent dynamical picture of interplanetary activity” on spatial scales from the Larmor radius to the outermost limits of the heliosphere and over a broad range of temporal scales. The spacecraft Voyagers 1 and 2 have taken us on a journey through much of the heliosphere: from Earth, past the termination shock near 90 AU, and into the inner heliosheath. This talk will use magnetic field observations from V1 and V2 to illustrate how Parker’s dynamical picture has been largely confirmed by observations out to ~100 AU. It will also discuss some “complicating aspects of the dynamics…which will turn up in future observations…” that Parker envisaged. With continued funding, the Voyager spacecraft will allow us to explore the heliosheath, cross the boundary of the heliosphere, and sample the local interstellar medium, guided by still untested predictions of Parker.

Burlaga, L. F.

2009-12-01

120

Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000.  

National Technical Information Service (NTIS)

This monograph contains brief descriptions of all robotic deep space missions attempted since the opening of the space age in 1957. The missions are listed strictly chronologically in order of launch date (not by planetary encounter).

A. A. Siddiqi

2002-01-01

121

Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000  

NASA Technical Reports Server (NTRS)

This monograph contains brief descriptions of all robotic deep space missions attempted since the opening of the space age in 1957. The missions are listed strictly chronologically in order of launch date (not by planetary encounter).

Siddiqi, Asif A.; Launius, Roger (Technical Monitor)

2002-01-01

122

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

NASA Technical Reports Server (NTRS)

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

1991-01-01

123

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

124

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

NASA Technical Reports Server (NTRS)

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

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

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

1996-01-01

125

Reconstruction of local magnetic properties of steel sheets by needle probe methods using space mapping techniques  

NASA Astrophysics Data System (ADS)

Cutting stresses introduced by punching influence the magnetic characteristics of electrical steels. A nondestructive experimental method used for measuring flux distributions in laminations is the needle probe method. The probe signals can be simulated by solving the two-dimensional nonlinear diffusion equation for the magnetic field in combination with a proper Preisach model. The Preisach parameters in several subregions of the steel sheet which best fit the input probe signals are obtained by solving the inverse problem. The method used for minimizing the cost function is the space mapping technique. This technique combines the fine model, which uses the finite element method, with a semianalytical coarse model, which reduces the nonlinear problem to a linear problem.

Crevecoeur, G.; Dupre, L.; Vandenbossche, L.; van de Walle, R.

2006-04-01

126

The Interstellar Medium: A Voyager Preview (Invited)  

NASA Astrophysics Data System (ADS)

For over two decades, Voyagers 1 and 2 have been exploring the interaction of the solar and interstellar wind and the properties of the local interstellar medium through a range of observations at increasing distances from the Sun. The slowing of the wind due to the ionization of interstellar neutral atoms, the elemental composition of the anomalous cosmic rays, the frequency of kilohertz radio emissions, the north/south asymmetry in the location of the termination shock, the magnetic pressure at the edge of the heliosphere, and the energy spectra and composition of low energy galactic cosmic rays have provided previews of the properties of interstellar space. An overview of these and other recent observations will be presented.

Stone, E. C.

2013-12-01

127

Voyager 2 Uranus targeting strategy  

NASA Technical Reports Server (NTRS)

One of the major challenges involved in the Voyager 2 Uranus flyby is to deliver the spacecraft to an appropriate aimpoint at the optimum time, so as to maximize the science return of the mission, while yet keeping propellant expenditure low. An unusual targeting strategy has been devised to satisfy these requirements. Its complexity arises from the great distance of the planet Uranus and the limited performance capabilities of Voyager. This selected strategy is developed in relation to a set of candidate strategies, mission requirements and shifting science objectives. The analysis of these candidates is conducted via a Monte Carlo simulation, the results of which yield data for the comparative evaluation and eventual and selection of the actual targeting strategy to be employed.

Cesarone, R. J.; Gray, D. L.; Potts, C. L.; Francis, K.

1986-01-01

128

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

129

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

NASA Technical Reports Server (NTRS)

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

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

1976-01-01

130

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

NASA Astrophysics Data System (ADS)

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 common situation in magnetically confined fusion plasmas. A method is proposed that allows the time-resolved reconstruction of the mode numbers and frequencies of eigenmodes in such a situation. It is based on the well known Lomb periodogram and has the following properties: statistical interpretation of the results, combined analysis of spatial and temporal data and effective noise reduction. Though this method can be generalized to arbitrary geometries, this work is dedicated to the analysis of Alfvén eigenmodes in stellarators. The method is applied to Mirnov probes which are found in many stellarators to diagnose Alfvén eigenmodes. Tests have been performed for the probe setup installed at the Wendelstein 7-AS stellerator, IPP Garching, Germany, for which experimental results are presented.

Zegenhagen, Stefan; Werner, Andreas; Weller, Arthur; Klinger, Thomas

2006-09-01

131

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

NASA Technical Reports Server (NTRS)

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

Juillerat, R.

1971-01-01

132

GRAVITY : Probing Space-Time and Faint Objects in the Infrared  

NASA Astrophysics Data System (ADS)

We introduce a new infrared adaptive optics assisted multiple-beam instrument for the VLTI infrastructure. With its high sensitivity, GRAVITY will be particularly suited for observing various types of faint targets of deep interest in the near-infrared. Precisely, one of the main goal of GRAVITY is to probe space-time at a few Schwarzschild radii of the center of the black hole located at the center of our galaxy thanks to an astrometric accuracy of 10 micro arcseconds.

Haubois, X.; Eisenhauer, F.; Perrin, G.; Rabien, S.; Eckart, A.; Lena, P.; Genzel, R.; Abuter, R.; Paumard, T.; Brandner, W.

133

Uruk Sulcus Mosaic - Galileo over Voyager Data  

NASA Technical Reports Server (NTRS)

A mosaic of four Galileo images of the Uruk Sulcus region on Ganymede (Latitude 11 N, Longitude: 170 W) is shown overlayed on the data obtained by the Voyager 2 spacecraft in 1979. North is to the top of the picture, and the sun illuminates the surface from the lower left, nearly overhead. The area shown is about 120 by 110 kilometers (75 by 68 miles) in extent and the smallest features that can be discerned are 74 meters (243 feet) in size in the Galileo images and 1.3 kilometers (0.8 miles) in the Voyager data. The higher resolution Galileo images unveil the details of parallel ridges and troughs that are principal features in the brighter regions of Ganymede. High photometric activity (large light contrast at high spatial frequencies) of this ice-rich surface was such that the Galileo camera's hardware data compressor was pushed into truncating lines. The north-south running gap between the left and right halves of the mosaic is a result of line truncation from the normal 800 samples per line to about 540. The images were taken on 27 June, 1996 Universal Time at a range of 7,448 kilometers (4,628 miles) through the clear filter of the Galileo spacecraft's imaging system.

Launched in October 1989, Galileo entered orbit around Jupiter on December 7, 1995. The spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

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

1996-01-01

134

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

Microsoft Academic Search

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

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

1981-01-01

135

Voyager 2 Neptune navigation results  

NASA Technical Reports Server (NTRS)

The Voyager 2 spacecraft encounter with the planet Neptune on Aug. 25, 1989 presented a difficult but interesting challenge for navigation. Final plans and strategies are compared with the actual performance obtained during the encounter in three areas. First, the orbit determination experience during encounter is reviewed, and the expected accuracy compared with the history of encounter period orbit estimates. Second, the trajectory correction maneuver history is outlined to show how the planned strategy was carried out to achieve desired science zones while assuring spacecraft safety. Third, the late update strategy is outlined and it is shown how this custom designed, complex procedure was used to support the near encounter science observations.

Gray, D. L.; Matousek, S. E.; Francis, K.; Potts, C. L.; Cesarone, R. J.

1990-01-01

136

Voyager Sails into Market for Reading  

ERIC Educational Resources Information Center

This article reports how the Voyager Universal Literacy core program, which is sailing successively into the market for reading programs, has been the target of several speculations over its secrets of success. Use of the Voyager Universal Literacy program has since spread to 1,000 districts throughout the country since its introduction into the…

Manzo, Kathleen Kennedy

2006-01-01

137

Voyager Briefing: Expectations of the Neptune Encounter  

NASA Technical Reports Server (NTRS)

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

1989-01-01

138

Titan. [Voyager IRIS observation of satellite atmosphere  

NASA Technical Reports Server (NTRS)

Saturn's satellite Titan is the second-largest in the solar system. Its dense atmosphere is mostly molecular nitrogen with an admixture of methane, a surface pressure of 1.5 bars and a surface temperature of 94K. The fundamental driving force in the long-term evolution of Titan's atmosphere is the photolysis of methane in the stratosphere to form higher hydrocarbons and aerosols. The current rate of photolysis and undersaturation of methane in the lower troposphere suggests the presence of a massive ethane-methane-nitrogen ocean. The ocean evolves to a more ethane-rich state over geologic time, driving changes in the atmospheric thermal structure. An outstanding issue concerning Titan's earliest history is the origin of atmospheric nitrogen: was it introduced into Titan as molecular nitrogen or ammonia? Measurement of the argon-to-nitrogen ratio in the present atmosphere provides a diagnostic test of these competing hypotheses. Many of the questions raised by the Voyager encounters about Titan and its atmosphere can be adequately addressed only by an entry probe, such as that planned for the Cassini mission.

Lunine, Jonathan I.

1990-01-01

139

46 CFR 46.05-20 - Great Lakes voyage.  

Code of Federal Regulations, 2013 CFR

... 2 2013-10-01 2013-10-01 false Great Lakes voyage. 46.05-20 Section 46.05-20...Definitions Used in This Part § 46.05-20 Great Lakes voyage. A Great Lakes voyage is any voyage from a United States...

2013-10-01

140

The Galilean satellites and Jupiter - Voyager 2 imaging science results  

Microsoft Academic Search

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

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

1979-01-01

141

Planetary radio astronomy observations from Voyager 2 near Jupiter  

Microsoft Academic Search

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

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

1979-01-01

142

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

NASA Astrophysics Data System (ADS)

How's the weather in space? Why on Earth did NASA send two satellites above Earth to study radiation belts and space weather? To learn the answer to questions about NASA's Van Allen Probes mission, 450 students and their teachers from Maryland middle schools attended Space Academy events highlighting the Van Allen Probes mission. Sponsored by the Applied Physics Laboratory (APL) and Discovery Education, the events are held at the APL campus in Laurel, MD. Space Academies take students and teachers on behind-the-scenes exploration of how spacecraft are built, what they are designed to study, and introduces them to the many professionals that work together to create some of NASA's most exciting projects. Moderated by a public relations representative in the format of an official NASA press conference, the daylong event includes a student press conference with students as reporters and mission experts as panelists. Lunch with mission team members gives students a chance to ask more questions. After lunch, students don souvenir clean room suits, enjoy interactive science demonstrations, and tour APL facilities where the Van Allen Probes were built and tested before launch. Students may even have an opportunity to peek inside a clean room to view spacecraft being assembled. Prior to the event, teachers are provided with classroom activities, lesson plans, and videos developed by APL and Discovery Education to help prepare students for the featured mission. The activities are aligned to National Science Education Standards and appropriate for use in the classroom. Following their visit, student journalists are encouraged to write a short article about their field trip; selections are posted on the Space Academy web site. Designed to engage, inspire, and influence attitudes about space science and STEM careers, Space Academies provide an opportunity to attract underserved populations and emphasize that space science is for everyone. Exposing students to a diverse group of scientists and engineers may alleviate some common stereotypes about these careers. When students engage with the scientists and engineers at APL, they see first-hand that successful science and engineering requires a diverse team with multi-disciplinary backgrounds. Activities throughout the day develop student understanding about science and technology, and address the fundamental concepts that fall under the National Science Education Content Standards. Students are immersed in a hands-on experience designed to facilitate understanding of the History and Nature of Science. Throughout the day students interact with people of diverse backgrounds and interests while hearing about the specific ways various individuals and teams of people contribute to the science and technology of the mission, addressing the concepts which fall under the headings of Science as a Human Endeavor, Nature of Science, and History of Science. Getting students outside the classroom to visit APL is an exclusive opportunity; evaluations have indicated that students became interested in learning more about space science and STEM careers after attending a Space Academy event.

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

2013-12-01

143

Voyager Observations of Anomalous Cosmic Rays in the Heliosheath  

NASA Astrophysics Data System (ADS)

The two Voyager spacecraft are now exploring the heliosheath. Voyager 1 (V1) crossed the termination shock in December 2004 and Voyager 2 (V2) crossed in August 2007. Recently, the intensities of anomalous cosmic rays (ACRs) have exhibited intriguing changes. At V1, the ACR He and O intensities have been declining since ~mid-2010. The decline suggests that the ACR source is not radially beyond 114 AU and that ACRs may be leaking out through the heliopause. If so, the V1 spacecraft may be close to entering interstellar space for the first time. At V2, the ACR He and O intensities began to rapidly increase near the beginning of 2010 and at several energies now exceed the intensities at V1. The V2 intensities are also higher than the peak intensities at V1 during 2010. The excess is nearly 100% for ACR O with energies 1.9-8.5 MeV/nuc and ~25% for ACR He with energies 6.2-12.8 MeV/nuc. These observations suggest that the ACR source intensity in the southern part of the heliosphere is greater than that in the north, or that the source of ACRs is along the flank or tail of the heliosphere. The latest observations will be presented at the meeting. This work was supported by NASA under contract NAS7-03001 and grant NNX10AE45G.

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

2011-12-01

144

Voyager-to-Galileo Changes, Io's Anti-Jove Hemisphere  

NASA Technical Reports Server (NTRS)

Shown here is a comparison of a Galileo color image (right) of Jupiter's moon Io, with a Voyager mosaic (left) reprojected to the same geometry as the Galileo image. The image on the right was obtained by the Galileo spacecraft's imaging camera on September 7th, 1996; the mosaic on the left was obtained by the Voyager spacecraft in 1979. Color is synthesized from green and violet filters only in both cases, as these are the only two filters that are reasonably similar between Voyager and Galileo. Many surface changes can be seen due to volcanic activity from 1979 to 1996. North is to the top of both frames. Galileo was about 487,000 kilometers (302,000 miles) from Io on September 7, 1996.

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

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

1996-01-01

145

Voyager 1 Red Spot Movie  

NASA Technical Reports Server (NTRS)

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

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

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

2000-01-01

146

Voyager 2 Jupiter Eruption Movie  

NASA Technical Reports Server (NTRS)

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

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

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

2000-01-01

147

Voyager observations of Zeta Tau  

NASA Technical Reports Server (NTRS)

Two Voyager observations of Zeta Tau, a well-known Be/shell star of spectral type B1 IVe and vsin(i) = 220 km/s, separated by 503 days are presented and discussed. The observations show that in the spectral region shortward of Lyman-alpha, the 950-1150 A flux increased by about 40 percent, while in the region longward of 1300 A the flux increased by about 30 percent. Changes in features at 975 A and at 1020 A also appear. The observed change in the continuum flux is probably associated with a change in the effective temperature of the underlying B star, though change in the ubiquitous Fe II lines cannot be ruled out as the cause. The line variations are consistent with IUE spectra of Zeta Tau taken during the same time period.

Carone, T. E.; Polidan, R. S.

1987-01-01

148

Voyager 2 Neptune targeting strategy  

NASA Technical Reports Server (NTRS)

The success of the Voyager 2 flybys of Neptune and Triton depends upon the ability to correct the spacecraft's trajectory. Accurate spacecraft delivery to the desired encounter conditions will promote the maximum science return. However, Neptune's great distance causes large a priori uncertainties in Neptune and Triton ephemerides and planetary system parameters. Consequently, the 'ideal' trajectory is unknown beforehand. The targeting challenge is to utilize the gradually improving knowledge as the spacecraft approaches Neptune to meet the science objectives, but with an overriding concern for spacecraft safety and a desire to limit propellant expenditure. A unique targeting strategy has been developed in response to this challenge. Through the use of a Monte Carlo simulation, candidate strategies are evaluated by the degree to which they meet these objectives and are compared against each other in determining the targeting strategy to be adopted.

Potts, C. L.; Francis, K.; Matousek, S. E.; Cesarone, R. J.; Gray, D. L.

1989-01-01

149

Voyages Through Time: Everything Evolves  

NASA Astrophysics Data System (ADS)

Evolutionary change is a powerful framework for studying our world and our place therein. It is a recurring theme in every realm of science: over time, the universe, the planet Earth, life, and human technologies all change, albeit on vastly different scales. Evolution offers scientific explanations for the age-old question, "Where did we come from?" In addition, historical perspectives of science show how our understanding has evolved over time. The complexities of all of these systems will never reveal a "finished" story. But it is a story of epic size, capable of inspiring awe and of expanding our sense of time and place, and eminently worthy of investigating. This story is the basis of Voyages Through Time. Voyages Through Time (VTT), provides teachers with not only background science content and pedagogy, but also with materials and resources for the teaching of evolution. The six modules, Cosmic Evolution, Planetary Evolution, Origin of Life, Evolution of Life, Hominid Evolution, and Evolution of Technology, emphasize student inquiry, and promote the nature of science, as recommended in the NSES and BSL. The modules are unified by the overarching theme of evolution and the meta questions: "What is changing?" "What is the rate of change?" and "What is the mechanism of change?" Determination of student outcomes for the project required effective collaboration of scientists, teachers, students and media specialists. The broadest curricula students outcomes are 1) an enjoyment of science, 2) an understanding of the nature of science, especially the understanding of evidence and re-evaluation, and 3) key science content. The curriculum is being developed by the SETI Institute, NASA Ames Research Center, California Academy of Sciences, and San Francisco State University, and is funded by the NSF (IMD 9730693), with support form Hewlett-Packard Company, The Foundation for Microbiology, Combined Federated Charities, NASA Astrobiology Institute, and NASA Fundamental Biology.

Pendleton, Y. J.; Tarter, J. C.; DeVore, E. K.; O'Sullivan, K. A.; Taylor, S. M.

2001-12-01

150

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

NASA Astrophysics Data System (ADS)

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

Fayock, Brian; Zank, Gary; Heerikhuisen, Jacob

2014-06-01

151

Voyager: Perils of advanced planning, 1960 - 1967  

NASA Technical Reports Server (NTRS)

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

1984-01-01

152

Voyager 1 Explores the "Magnetic Highway"  

NASA Video Gallery

This set of animations show NASA's Voyager 1 spacecraft exploring a new region in our solar system called the "magnetic highway." In this region, the sun's magnetic field lines are connected to int...

153

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

NASA Technical Reports Server (NTRS)

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

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

1983-01-01

154

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

155

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

156

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

PubMed

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. PMID:24007060

Baude, R; Gaboriau, F; Hagelaar, G J M

2013-08-01

157

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

SciTech Connect

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

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

2013-08-15

158

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

PubMed

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

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

2011-06-01

159

GRAVITY, Probing Space-time And Faint Objects In The Infrared.  

NASA Astrophysics Data System (ADS)

We introduce a new infrared adaptive optics assisted multiple-beam instrument for the VLTI infrastructure. GRAVITY (standing for General Relativity Analysis via VLT InterferometrY) will allow simultaneous observations of two objects by phase-referenced interferometric imaging and narrow angle astrometry with a high sensitivity. For those reasons, GRAVITY is particularly suited for observing various types of faint targets of deep interest in the near-infrared such as AGNs, starclusters, intermediate black holes, substellar objects, planets. Precisely, one of the main goal of GRAVITY is to probe space time around the intermediate mass black hole at the center of our galaxy. We will able to detect relativistic effects at a few Schwarzschild radii of the center of the black hole thanks to an astrometric accuracy of 10 micro arcseconds. We will present the instrumental concept of GRAVITY and discuss some of the future scientific prospects that it will offer.

Haubois, X.; Eisenhauer, F.; Perrin, G.; Rabien, S.; Eckart, A.; Lena, P.; Genzel, R.; Abuter, R.; Paumard, T.; Brandner, W.

2006-08-01

160

Space-resolved dynamic light scattering probing inhomogeneous dynamics in soft matter  

NASA Astrophysics Data System (ADS)

We describe a new designed multispeckle correlation spectroscopy (MSCS) setup which uses a CCD-camera as optical detector. Due to the simultaneous detection of many coherence areas (speckles) we get a much better statistic than in standard dynamic light scattering (DLS) measurements. Furthermore the intermediate scattering function (ISF) for nonergodic samples can be determined from one measurement. A special feature of our setup is the direct imaging of the scattering volume on the CCD-camera. Therefore every speckle can be connected to its origin scattering volume. This space-resolution gives us the possibility to probe the particle dynamics at different sample positions. Further, we present frequency distributions of the intensity autocorrelation functions for a fluid and a metastable sample.

Golde, Sebastian; Franke, Markus; Schöpe, Hans Joachim

2013-02-01

161

Saturn Helium Abundance: A Reanalysis of Voyager Measurements  

NASA Astrophysics Data System (ADS)

Thermal emission spectra calculated using Voyager Jupiter radio occultation (RSS) temperature profiles rescaled to the Galileo probe value of the helium abundance do not agree with the spectra measured by the Voyager infrared spectrometer (IRIS). The ˜2 K offset in brightness temperature suggests the possibility of a systematic error source yet to be identified. This raises the question of the validity of the Voyager Saturn helium abundance that was determined using the same RSS-IRIS approach. We address this issue by developing an inversion algorithm for the simultaneous retrieval of the temperature, the para H 2 fraction, and the helium abundance from the IRIS spectra alone. This approach can not be successfully applied to Jupiter because of strong gaseous NH 3 and cloud opacity near the low-frequency end of the spectrum, but this restriction is less severe at the lower temperatures of Saturn. Applications of the algorithm to Saturn spectra yield a volume mixing ratio He/H 2 between 0.11 and 0.16 corresponding to a helium mass fraction relative to the total helium and hydrogen in Saturn's atmosphere of Y=0.18-0.25. Although these retrievals depend on subjective filtering of the solutions in the inversion algorithm to reduce the range of non-uniqueness for the helium values, they strongly suggest a value for He/H 2 significantly larger than the value of 0.034±0.024 previously obtained by Conrath et al. (Conrath, B. J., D. Gautier, R. A. Hanel, and J. S. Hornstein 1984, Astrophys. J.282, 807-815) using the RSS-IRIS method.

Conrath, Barney J.; Gautier, Daniel

2000-03-01

162

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

163

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

164

Estimation of a melting probe's penetration velocity range to reach icy moons' subsurface ocean  

NASA Astrophysics Data System (ADS)

In modern space science one of the actual branches is icy satellites explorations. The main interest is concentrated around Jovian's moons Europa and Ganymede, Saturn's moons Titan and Enceladus that are covered by thick icy layer according to "Voyager1", "Voyager2", "Galileo" and "Cassini" missions. There is a big possibility that under icy shell could be a deep ocean. Also conditions on these satellites allow speculating about possible habitability, and considering these moons from an astrobiological point of view. One of the possible tasks of planned missions is a subsurface study. For this goal it is necessary to design special equipment that could be suitable for planetary application. One of the possible means is to use a melting probe which operates by melting and moves by gravitational force. Such a probe should be relatively small, should not weight too much and should require not too much energy. In terrestrial case such kind of probe has been successfully used for glaciers study. And it is possible to extrapolate the usage of such probe to extraterrestrial application. One of the tasks is to estimate melting probe's penetration velocity. Although there are other unsolved problems such as analyzing how the probe will move in low gravity and low atmospheric pressure; knowing whether hole will be closed or not when probe penetrate thick enough; and considering what order could be a penetration velocity. This study explores two techniques of melting probe's movement. One of them based on elasto-plastic theory and so-called "solid water" theory, and other one takes phase changing into account. These two techniques allow estimating melting probe's velocity range and study whole process. Based on these technique several cases of melting probe movement were considered, melting probe's velocity range estimated, influence of different factors studied and discussed and an easy way to optimize parameters of the melting probe proposed.

Erokhina, Olga; Chumachenko, Eugene

2014-05-01

165

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

NASA Technical Reports Server (NTRS)

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

Kursinski, Emil R.

1990-01-01

166

A summary of whistlers observed by Voyager 1 at Jupiter  

NASA Technical Reports Server (NTRS)

We summarize the Voyager 1 observations of whistlers at Jupiter in order to provide a basis for further analyses of the density profile of the Io plasma torus as well as to support studies of atmospheric lightning at Jupiter. All the whistlers detected by Voyager 1 fell into three general regions in the torus at radial distances ranging beteen 5 and 6 R sub J. An analysis of the broadband wave amplitudes measured by the Voyayer 1 plasma wave instrument and estimates of the peak whistler amplitudes imply the grouping of whistlers was due to variations in the sensitivity of the receiver to whistlers and not to variations in the source or propagation paths of the whistlers. The whistler dispersions are presented in statistical form for each of the three groups of events and analyzed in view of the structure of the Io plasma torus as determined by plasma probe measurements. The results of these analyses give source locations for the whistlers at the foot of the magnetic field lines threading the torus in both hemispheres and over a range of longitudes.

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

1985-01-01

167

Summary of whistlers observed by Voyager 1 at Jupiter  

SciTech Connect

We summarize the Voyager 1 observations of whistlers at Jupiter in order to provide a basis for further analyses of the density profile of the Io plasma torus as well as to support studies of atmospheric lightning at Jupiter. All the whistlers detected by Voyager 1 fell into three general regions in the torus at radial distances ranging beteen 5 and 6 R sub J. An analysis of the broadband wave amplitudes measured by the Voyayer 1 plasma wave instrument and estimates of the peak whistler amplitudes imply the grouping of whistlers was due to variations in the sensitivity of the receiver to whistlers and not to variations in the source or propagation paths of the whistlers. The whistler dispersions are presented in statistical form for each of the three groups of events and analyzed in view of the structure of the Io plasma torus as determined by plasma probe measurements. The results of these analyses give source locations for the whistlers at the foot of the magnetic field lines threading the torus in both hemispheres and over a range of longitudes. 27 references.

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

1985-03-01

168

Measurement of Space Potential Fluctuations During MHD Activities in a Toroidal Helical Plasma with a Heavy Ion Beam Probe  

Microsoft Academic Search

A heavy ion beam probe (HIBP) is a unique diagnostic instrument which can measure local plasma potential and its fluctuations. However, in the presence of MHD activities, acceleration or deceleration of both primary and secondary beams are caused by the fluctuating vector potential ?A\\/?t along the beam trajectories (path integral effect). Such effect possibly induces a contamination to space potential

Seishu Lee; Harukazu Iguchi; Akihide Fujisawa; Thomas P. Crowley; Yasuji Hamada; Mamoru Kojima; Ryuichi Akiyama; Keisuke Matsuoka; Shoichi Okamura; Chihiro Takahashi

1998-01-01

169

Observations of Mesoscale and Microscale Space Weather Processes on the Canadian ASSIOPE Enhanced Polar Outflow Probe (e-POP)  

Microsoft Academic Search

CASSIOPE is a Canadian small satellite scheduled for launch in late 2007 into a polar orbit 300 times 1500 km 80 r inclination The scientific objective of its Enhanced Polar Outflow Probe e-POP payload is to make observations of mesoscale and microscale space weather processes in the topside polar ionosphere at the highest-possible resolution specifically to study the microscale characteristics

A. W. Yau; H. G. James

2006-01-01

170

Miranda as seen by Voyager 2  

NASA Technical Reports Server (NTRS)

Flying by in early 1986, Voyager 2 captured this picture of Miranda, which enabled scientists to study this moon of Uranus in much greater detail than ever before. Discovered in 1948 by Gerard Peter Kuiper, Miranda is named for the daughter of the wily Prospero in Shakespeare's 'The Tempest.' It is the eleventh known satellite of Uranus and the innermost large moon of Uranus It was necessary that Voyager 2 passed by Miranda, not for scientific reasons, but simply for the gravity assist it needed to go on to Neptune. Due to the position of the entire Solar System, Miranda provided the energy to throw Voyager 2 to Neptune. Before Voyager, Miranda was largely ignored as it is not the largest moon and did not seem to have any other outstanding qualities. Fortunately, however, Voyager passed close enough to Miranda to provide scientists with fascinating photographs that captivated astronomers. About half ice and half rock, Miranda's surface has terraced layers that indicate both older and new surfaces coexisting. Since the mixing of ancient and recent surfaces is rare in planetary geology, scientists have postulated two explanations for the different ages of the numerous valleys and cliffs on Miranda. One theory is that Miranda could have shattered as many as five times and was then reassembled. Another hypothesis is that partly melted ice upwells forced new surfaces to emerge.

1986-01-01

171

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

172

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.

173

Darwin: Voyage of Discovery (ScienceWorld)  

NSDL National Science Digital Library

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

174

The extraordinary voyages through the region of the giant planets  

NASA Astrophysics Data System (ADS)

The astronautical achievements necessary for guiding Pioneer 10 and 11 and Voyager I and II to the giant planets are reviewed. The spacecraft were equipped with rocket exhausts for both orbital corrections and revolution about their axis. Calculations for the Hohmann transfer orbit are performed, noting that the most efficient trajectory to Jupiter is elliptical, and that the launch dates were strictly circumscribed by the condition that the heliocentric position of Jupiter was necessarily 97 deg longitudinally greater than earth's at the launch. Considerations given to the transition of the dominant gravitational force from the sun to Jupiter are described, together with the calculation procedures. The encounters of each planetary body (and their moons) by each of the probes is detailed. The benefits of gravity assists for gaining velocity are outlined, and the bext favorable window for another grand tour is identified in the 1993-1997 interval

Danloux-Dumesnils, M.

1983-01-01

175

Advanced Receiver tracking of Voyager 2 near solar conjunction  

NASA Technical Reports Server (NTRS)

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

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

1988-01-01

176

Space research in the era of the space station  

NASA Technical Reports Server (NTRS)

The historical development of U.S. space technology is examined as a basis for future programs planned in the field of astrophysics, meteorological and land sciences, and planetary exploration. The background of the NASA space station project is described, as well as other current programs: Voyager II for Uranus and Neptune exploration, Galileo mission for sending probes into the Jovian atmosphere, Venus Radar Mapper, Mars Geochemistry and Climatology Orbiter, and the International Solar Polar mission. Recent advances in in-orbit assembly, refurbishment and repairs are discussed through the example of the Solar Maximum mission spacecraft repair in 1984 and the use of the RMS tool. The U.S. space observatory project with a 20-meter reflector telescope, currently in the early definition stage, is also discussed. Finally, the Soviet Salyut and Soyuz missions, together with the Soviet Union's study of long term flight conditions are mentioned as possible comparison with the NASA work.

Frost, K. J.; Mcdonald, F. B.

1984-01-01

177

Uranus - Voyager visits a dark planet  

Microsoft Academic Search

A brief chronology and summary of the results of early data analysis is presented of events which transpired as Voyager 2 performed a flyby of Uranus. The spacecraft instrumentation relayed data on the Uranian magnetic field, radio occultations caused by the ring system, and spectrographic data of the planet and the moons. Numerous photographic reproductions are provided of the imagery

R. Gore

1986-01-01

178

The Voyager 2 encounter with Uranus  

Microsoft Academic Search

The instruments and science investigations of the Voyager 2 payload are listed in tables and illustrated with a drawing, and a general overview of the encounter with Uranus in January 1986 is given. The spacecraft approached to within 107,100 km of the center of Uranus, and to within 29,000 km of the Uranian satellite Miranda before continuing on for an

E. C. Stone

1987-01-01

179

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.

180

Antenna arraying of Voyager telemetry signals by symbol stream combining  

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

181

Babylon to Voyager and Beyond  

NASA Astrophysics Data System (ADS)

Preface; Introduction; 1. The ancients; 2. Copernicus and the new cosmology; 3. Kepler and Galileo - the fall of epicycles and the start of telescopic astronomy; 4. The mid and late seventeenth century; 5. Consolidation; 6. The solar system expands; 7. The inner solar system in the nineteenth century; 8. The outer solar system in the nineteenth century; 9. Quiet interlude - the twentieth century prior to the space age; 10. The space age - terrestrial planets; 11. The space age - the outer planets; Glossary; Bibliography; Units; Name index; Subject index.

Leverington, David

2007-07-01

182

Polarisation measurements with Voyager and Cassini  

NASA Astrophysics Data System (ADS)

The Voyager 1 and 2 missions to the outer planets carried a Photopolarimeter instrument, and the Cassini Imaging Science Subsystem includes linear polarisers to make polarisation images of Jupiter, Saturn, and its moons and rings. The Voyager 1 Photopolarimeter instrument failed before Jupiter encounter but the Voyager 2 instrument returned polarimetry data from Jupiter, Saturn, Titan, Uranus and Neptune at two wavelengths (240 nm and 750 nm), extending previous Pioneer polarisation measurements in wavelength and scattering angle. Its most important contribution to polarisation science came at Titan. The combined polarisation information from the Pioneer 11 IPP instrument, Voyager 2 PPS, and photometry from the Voyager cameras, led to the conclusion that the haze particles in Titan's atmosphere are aggregates of much smaller particles (~60 nm radius). This idea is now the paradigm for the morphology of the Titan haze particles. Observations by the Cassini ISS extended this finding to the polar haze of Saturn which is also highly polarizing, as is Jupiter's polar haze. An auroral mechanism is implicated. The Cassini polarisation measurements can be combined with passband filters to sample from the near-UV to the near-IR, including the narrow methane absorption bands. Outside of the polar regions, for both Jupiter and Saturn, the polarisation of the upper tropospheric clouds is quite low as expected from ice crystals larger than the wavelength. Polarisation measurements in those regions help define cloud altitudes from the signature of the overlying Rayleigh scattering by gas molecules. The Cassini polarisation images of icy satellites show correlation with surface albedo as expected if multiple scattering in surface grains is damped out for absorbing surfaces. This abstract was prepared by the Jet Propulsion Laboratory, California Institute of Technology.

West, R.

2012-04-01

183

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

184

Galileo Regio Mosaic - Galileo over Voyager Data  

NASA Technical Reports Server (NTRS)

A mosaic of four Galileo images of the Galileo Regio region on Ganymede (Latitude 18 N, Longitude: 149 W) is shown overlayed on the data obtained by the Voyager 2 spacecraft in 1979. North is to the top of the picture, and the sun illuminates the surface from the lower left, about 58 degrees above the horizon. The smallest features that can be discerned are about 80 meters (262 feet) in size in the Galileo images. These Galileo images show fine details of the dark terrain that makes up about half of the surface of the planet-sized moon. Ancient impact craters of various sizes and states of degradation testify to the great age of the terrain, dating back several billion years. The images reveal distinctive variations in albedo from the brighter rims, knobs, and furrow walls to a possible accumulation of dark material on the lower slopes, and crater floors. High photometric activity (large light contrast at high spatial frequencies) of this ice-rich surface was such that the Galileo camera's hardware data compressor was pushed into truncating lines. The north-south running gap between the left and right halves of the mosaic is a result of line truncation from the normal 800 samples per line to about 540. The images were taken on 27 June, 1996 Universal Time at a range of 7,580 kilometers (4,738 miles) through the clear filter of the Galileo spacecraft's imaging system. Launched in October 1989, Galileo entered orbit around Jupiter on December 7, 1995. The spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

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

1996-01-01

185

On Whether or Not Voyager 1 has Crossed the Heliopause  

NASA Astrophysics Data System (ADS)

The Voyager 1 spacecraft is currently in the vicinity of the heliopause, which separates the heliosphere from the local interstellar medium. There has been a precipitous decrease in particles accelerated in the heliosphere, and a substantial increase in galactic cosmic rays (GCRs), suggesting easy escape of the former across the heliopause, and entry of the latter. The question is, has Voyager 1 actually crossed the heliopause and is it now in the interstellar medium? We contend that the evidence is inconclusive. The direction of the magnetic field observed by Voyager 1 is unchanged from the direction of the heliospheric magnetic field, and different from the expected direction of the interstellar magnetic field. However, the plasma density, which is measured from observations of plasma waves, is similar to the expected interstellar density and much larger than the solar wind plasma density observed by Voyager 2 (which has a working plasma detector) at smaller heliocentric distances than Voyager 1. In this paper, an analytic model is presented that is based upon and is consistent with all Voyager observations, and in which the higher plasma densities measured by Voyager 1 are due simply to compressed solar wind. Thus both the magnetic field and the plasma density observations are consistent with Voyager 1 still remaining well within the heliosheath. The model has a simple test: Voyager 1 should encounter a magnetic sector boundary crossing, where the behavior of particles accelerated in the heliosphere and the GCRs will be different from what Voyager 1 is now observing.

Fisk, L. A.; Gloeckler, G.

2014-07-01

186

Studies of the interplanetary magnetic field: IMP's to Voyager  

NASA Technical Reports Server (NTRS)

During the last two decades, spacecraft projects and individual experiments for which Frank McDonald was a leader have contributed very significantly to the current understanding of the structure of interplanetary space and the correlation between solar and interplanetary disturbances. Studies on the IMP, HELIOS, and Pioneer spin-stabilized spacecraft and the larger attitude-stabilized Voyager spacecraft have provided data sets from which the modern view of the heliosphere has evolved. That concept in which the inner solar system is shown to be dominated by individual streams associated with specific source regions on the Sun is illustrated. As these high-speed streams overtake the preexisting solar plasma, they coalesce and modify the characteristics so that at larger heliocentric distances, these disturbances appear as radially propagating concentric shells of compressed magnetic fields and enhanced fluctuations

Ness, Norman F.

1987-01-01

187

Magnetic field studies at jupiter by voyager 1: preliminary results.  

PubMed

Results obtained by the Goddard Space Flight Center magnetometers on Voyager 1 are described. These results concern the large-scale configuration of the Jovian bow shock and magnetopause, and the magnetic field in both the inner and outer magnetosphere. There is evidence that a magnetic tail extending away from the planet on the nightside is formed by the solar wind-Jovian field interaction. This is much like Earth's magnetosphere but is a new configuration for Jupiter's magnetosphere not previously considered from earlier Pioneer data. We report on the analysis and interpretation of magnetic field perturbations associated with intense electrical currents (approximately 5 x 10(6) amperes) flowing near or in the magnetic flux tube linking Jupiter with the satellite Jo and induced by the relative motion between Io and the corotating Jovian magnetosphere. These currents may be an important source of heating the ionosphere and interior of Io through Joule dissipation. PMID:17800435

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

1979-06-01

188

Availability of Feature-Oriented Scanning Probe Microscopy for Remote-Controlled Measurements on Board a Space Laboratory or Planet Exploration Rover  

Microsoft Academic Search

Prospects for a feature-oriented scanning (FOS) approach to investigations of sample surfaces, at the micrometer and nanometer scales, with the use of scanning probe microscopy under space laboratory or planet exploration rover conditions, are examined. The problems discussed include decreasing sensitivity of the onboard scanning probe microscope (SPM) to temperature variations, providing autonomous operation, implementing the cap- abilities for remote

Rostislav V. Lapshin

2009-01-01

189

Modulation of the Foreign Body Reaction for Implants in the Subcutaneous Space: Microdialysis Probes as Localized Drug Delivery/Sampling Devices  

PubMed Central

Modulation of the foreign body reaction is considered to be an important step toward creation of implanted sensors with reliable long-term performance. In this work, microdialysis probes were implanted into the subcutaneous space of Sprague-Dawley rats. The probe performance was evaluated by comparing collected endogenous glucose concentrations with internal standard calibration (2-deoxyglucose, antipyrine, and vitamin B12). Probes were tested until failure, which for this work was defined as loss of fluid flow. In order to determine the effect of fibrous capsule formation on probe function, monocyte chemoattractant protein-1/CC chemokine ligand 2 (MCP-1/CCL2) was delivered locally via the probe to increase capsule thickness and dexamethasone 21-phosphate was delivered to reduce capsule thickness. Probes delivering MCP-1 had a capsule that was twice the thickness (500–600 ?m) of control probes (200–225 ?m) and typically failed 2 days earlier than control probes. Probes delivering dexamethasone 21-phosphate had more fragile capsules and the probes typically failed 2 days later than controls. Unexpectedly, extraction efficiency and collected glucose concentrations exhibited minor differences between groups. This is an interesting result in that the foreign body capsule formation was related to the duration of probe function but did not consistently relate to probe calibration.

Mou, Xiaodun; Lennartz, Michelle R; Loegering, Daniel J; Stenken, Julie A

2011-01-01

190

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

191

Voyager 2 plasma wave observations at Uranus  

NASA Technical Reports Server (NTRS)

At Uranus, the Voyager 2 plasma wave investigation observed very significant phenomena related to radio emissions, dust impacts, and magnetospheric wave-particle interactions. On January 19, 1986 (R = 270 R-sub U) the plasma wave investigation detected an intense radio burst at 31 and 56 kHz, and this provided the first indication that Uranus had a magnetosphere. During the encounter, more of these sporadic bursts were observed along with relatively continuous radio emissions extending down to 10 kHz, and a sporadic narrowband radio signal with f near 5 kHz. As Voyager passed through the ring plane, the plasma wave investigation recorded a large number of dust impacts. The Voyager 2 plasma wave instrument also detected many strong electromagnetic and electrostatic plasma waves, with intensity peaks in the region within 12 Uranus radii. These waves have characteristics that can interact strongly with the local plasma and with the trapped energetic particles, leading to precipitation into the atmosphere, charged particle acceleration, and charged particle diffusion. In addition, strong wave activity was detected in the region of the bow and shock and moderate levels in the magnetic tail.

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

1987-01-01

192

Voyager 2 Movie of Saturn's Moon: Phoebe  

NASA Technical Reports Server (NTRS)

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

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

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

2000-01-01

193

Voyager 2's encounter with the gas giants  

NASA Astrophysics Data System (ADS)

The findings made by Voyager 2 as it passed by the gas giants are reviewed. The unexpected problems that had to be overcome during the mission, including receiver failure and scan platform problems, are described. The scientific instrumentation aboard Voyager is briefly examined, and the major types of Voyager scientific investigations and principal investigators are listed. The scientific findings regarding the atmospheres, thermal properties, electromagnetic environments, ring systems, satellite surfaces, body properties, and bulk properties are examined.

Miner, E. D.

1990-07-01

194

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

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

195

Is Voyager 1 inside an Interstellar Flux Transfer Event?  

NASA Astrophysics Data System (ADS)

Plasma wave observations from Voyager 1 have recently shown large increases in plasma density, to about 0.1 cm-3, consistent with the density of the local interstellar medium. However, corresponding magnetic field observations continue to show the spiral magnetic field direction observed throughout the inner heliosheath. These apparently contradictory observations may be reconciled if Voyager 1 is inside an interstellar flux transfer event—similar to flux transfer events routinely seen at the Earth's magnetopause. If this were the case, Voyager 1 remains inside the heliopause and based on the Voyager 1 observations we can determine the polarity of the interstellar magnetic field for the first time.

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

2013-12-01

196

Voyager 1 UVS measurements of Galactic cosmic rays  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

197

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

Microsoft Academic Search

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

Pascale Ehrenfreund; Steven B. Charnley

2000-01-01

198

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

NASA Technical Reports Server (NTRS)

The three NASA/USAF lunar probes of August 17, October 13, and November 8, 1958 are described. Details of the program, the vehicles, the payloads, the firings, the tracking, and the results are presented. Principal result was the first experimental verification of a confined radiation zone of the type postulated by Van Allen and others.

1959-01-01

199

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

NASA Technical Reports Server (NTRS)

The three NASA/USAF lunar probes of August 17, October 13, and November 8, 1958 are described. Details of the program, the vehicles, the payloads, the firings, the tracking, and the results are presented. Principal result was the first experimental verification of a confined radiation zone of the type postulated by Van Allen and others.

1959-01-01

200

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

NASA Astrophysics Data System (ADS)

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 done to build a numerical model of the dynamics of the exploration. A probabilistic analysis is subsequently conducted in order to obtain bounds on the number of ETCs that may be exploring the galaxy without establishing contact with Earth, depending on factors such as the number of probes they use, their lifetime and whether they leave some long-term imprint on explored systems or not. The results indicate that it is unlikely that more than ~102-103 ETCs are exploring the galaxy in a given Myr, if their probes have a lifetime of 50 Myr and contact evidence lasts for 1 Myr. This bound goes down to ~10 if contact evidence lasts for 100 Myr, and is also shown to be inversely proportional to the lifetime of probes. These results are interpreted in light of the Fermi paradox and are compatible with non-stationary astrobiological models in which a few ETCs have gradually appeared in the Fermi-Hart timescale.

Cotta, C.; Morales, A.

201

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

202

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

203

Capacitance Probe Sensor Device.  

National Technical Information Service (NTIS)

A capacitance probe sensor device is disclosed which is a probe formed of KYNAR insulated wire spaced from an uninsulated metallic ground electrode. An oscillator and associated capacitance-resistance network connected to the probe serve to provide a line...

M. Gutierrez

1980-01-01

204

Summary of whistlers observed by Voyager 1 at Jupiter. Progress report  

SciTech Connect

We summarize the Voyager 1 observations of whistlers at Jupiter in order to provide a basis for further analyses of the density profile of the Io plasma torus as well as to support studies of atmospheric lightning at Jupiter. All the whistlers detected by Voyager 1 fell into three general regions in the torus at radial distances ranging between 5 and 6 R sub J. An analysis of the broadband wave amplitudes measured by the Voyager 1 plasma wave instrument and estimates of the peak whistler amplitudes imply the grouping of whistlers was due to variations in the sensitivity of the receiver to whistlers and not to variations in the source or propagation paths of the whistlers. The whistler dispersions are presented in statistical form for each of the three groups of events and analyzed in view of the structure of the Io plasma torus as determined by plasma probe measurements. The results of these analyses give source locations for the whistlers at the foot of the magnetic field lines threading the torus in both hemispheres and over a range of longitudes.

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

1983-12-20

205

The Use of Langmuir Probes in Non-Maxwellian Space Plasmas  

NASA Technical Reports Server (NTRS)

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

Hoegy, Walter R.; Brace, Larry H.

1998-01-01

206

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

NASA Technical Reports Server (NTRS)

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

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

2000-01-01

207

Engineering Voyager 2's encounter with Uranus  

NASA Technical Reports Server (NTRS)

Changes made by radio control from the ground in the Voyager 2 spacecraft as it approached Uranus are described. Reduced power required that subsystems and heaters had to be switched on and off in carefully synchronized fashion. Low light levels required increased exposure times, so the jiggling of the spacecraft had to be minimized. Coding changes were made and image data were compressed to cope with the reduced bit rate at larger distances. Successful efforts to cope with failures in the primary radio receiver and in the computer instructions for image compression are described, as are changes made on the ground in the spacecraft navigation.

Laeser, Richard P.; Mclaughlin, William I.; Wolff, Donna M.

1986-01-01

208

The Voyager 2 encounter with Uranus  

NASA Technical Reports Server (NTRS)

The instruments and science investigations of the Voyager 2 payload are listed in tables and illustrated with a drawing, and a general overview of the encounter with Uranus in January 1986 is given. The spacecraft approached to within 107,100 km of the center of Uranus, and to within 29,000 km of the Uranian satellite Miranda before continuing on for an encounter with Neptune in 1989; the trajectory also permitted radio occultation studies of the Uranian rings and radio and UV occultation studies of the planet's atmosphere. Diagrams of the trajectory are provided.

Stone, E. C.

1987-01-01

209

Darwin: Voyage of Discovery (SuperScience)  

NSDL National Science Digital Library

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

210

Command and control of the Voyager spacecraft  

NASA Technical Reports Server (NTRS)

The Voyager Mission was designed to be conducted using reprogrammable onboard computers. This decision was based on the need for highly reliable semi-autonomous operations of the spacecraft and the lengthy two-way communication times envisioned during the mission. Command and control of the spacecraft is effected by the process through which the programs for these computers are developed. While this results in a relatively passive real-time command and control function, provisions exist for intervention to occur in order to modify or augment the programs or respond to spacecraft anomalies.

Adamski, Terrence P.

1987-01-01

211

NASA reconfigures Voyager 2, ground stations for Uranus flyby  

Microsoft Academic Search

Changes have been implemented on board the Voyager 2 spacecraft and at NASA ground stations to ensure continued signal reception at both ends of the link. Voyager 2 will be 1.8 billion miles from earth during its Uranus encounter. The primary ground link will be the 64 m and two 34 m antennas at the NASA Australian complex. The data

B. A. Smith

1985-01-01

212

Erratum: Voyager Color Photometry of Saturn's Main Rings.  

National Technical Information Service (NTIS)

We correct a calibration error in our earlier analysis of Voyager color observations of Saturn's main rings at 14 deg phase angle and present thoroughly revised and reanalyzed radial profiles of the brightness of the main rings in Voyager G, V, and UV fil...

P. R. Estrada J. N. Cuzzi M. R. Showalter

2002-01-01

213

Plasma waves near Saturn: initial results from Voyager 1  

Microsoft Academic Search

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

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

1981-01-01

214

Plasma observations near Jupiter: initial results from Voyager 1  

Microsoft Academic Search

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

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

1979-01-01

215

Recent Observations of Energetic Particles from the Voyager Spacecraft  

NASA Astrophysics Data System (ADS)

The Voyager spacecraft have been exploring the heliosheath since their crossings of the solar wind termination shock on December 2004 (Voyager 1) and August 2007 (Voyager 2). Starting on 7 May 2012, dramatic short-term changes in the intensities of heliospheric particles and galactic cosmic rays have been occurring periodically at Voyager 1. In July, a series of encounters with a heliospheric depletion region occurred, culminating on 25 August 2012 with the durable entry into the region by Voyager 1 (durable at least through the time of this writing in early February 2012). This depletion region is characterized by the disappearance of particles accelerated in the heliosphere, the anomalous cosmic rays and termination shock particles, and the increased intensity of galactic cosmic ray nuclei and electrons. The result is that the low-energy part of the galactic cosmic ray spectra is being revealed for the first time. Data from the magnetometer experiment on Voyager 1 implies that the spacecraft is not yet in the interstellar medium, but it apparently has a good connection path to it. At Voyager 2, dramatic changes haven't occurred but there are longer-term trends in the intensities that are different from what were observed on Voyager 1. We will report on the recent observations of energetic particles from both spacecraft. This work was supported by NASA under contract NNN12AA012.

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

2013-05-01

216

Voyager 1 observes low-energy galactic cosmic rays in a region depleted of heliospheric ions.  

PubMed

On 25 August 2012, Voyager 1 was at 122 astronomical units when the steady intensity of low-energy ions it had observed for the previous 6 years suddenly dropped for a third time and soon completely disappeared as the ions streamed away into interstellar space. Although the magnetic field observations indicate that Voyager 1 remained inside the heliosphere, the intensity of cosmic ray nuclei from outside the heliosphere abruptly increased. We report the spectra of galactic cosmic rays down to ~3 × 10(6) electron volts per nucleon, revealing H and He energy spectra with broad peaks from 10 × 10(6) to 40 × 10(6) electron volts per nucleon and an increasing galactic cosmic-ray electron intensity down to ~10 × 10(6) electron volts. PMID:23811227

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

2013-07-12

217

Study of space charge in polyethylene for cable insulation by direct probing  

Microsoft Academic Search

By utilizing the laser-induced-pressure-pulse (LIPP) technique, the authors quantitatively studied the behavior of space charge in polyethylene (PE) for cable insulation to clarify the space charge effects in power cables. Effects of crosslinking, carbon-loaded semiconducting layer and additives (antioxidant) are reported. Crosslinked polyethylene (XLPE) with metal electrodes showed negative homo charge near the cathode, suggesting that crosslinking enhances electron injection

Y. Suzuoki; H. Matsukawa; S.-O. Han; T. Mizutani; M. Ieda; N. Yoshifuji

1991-01-01

218

BrainVoyager--past, present, future.  

PubMed

BrainVoyager started as a simple fMRI analysis tool in the mid 1990s; the software was primarily created to fulfill the needs of its author and his colleagues to analyze anatomical and functional MRI data in a way that would be most appropriate for their research questions in visual and auditory perception. More specifically, the software was designed with three major goals in mind. First, it should allow analyses that would exploit optimally the high-resolution information available in fMRI data. Second, it should integrate volume-based analysis and cortex-based analysis including the possibility to visualize topographic activation data on flattened cortex representations. Third, it should combine hypothesis testing with data-driven analysis including interactive visualization tools that would make it as easy as possible to look at and explore data. A fourth guiding principle was to develop a software package that fulfilled the author's preference for elegant user interfaces, beautiful visualizations and high-performance computing. These major guiding principles from the beginning of BrainVoyager development are still noticeable in the most recent incarnations of the software that has grown from a small fMRI analysis tool on the Windows platform to a comprehensive cross-platform multi-modal software package integrating (real-time) fMRI, DWI/DTI, (i)EEG, MEG, TMS and fNIRS analyses. PMID:22289803

Goebel, Rainer

2012-08-15

219

Idealized Voyager Jovian magnetosphere shape and field  

SciTech Connect

A magnetic field arising from the Jovian equatorial sheet current deduced from Voyager 1 and 2 observations has been added to a planetary dipole field to provide a model of magnetic field inside the magnetopause. This internal field was used to calculate the magnetopause surface in a cyclic process. During each cycle, the surface was calculated, and the resulting field due to currents on the magnetopause was calculated for inclusion in the total field used to calculate the next-order surface. The resulting magnetopause is, as anticipated, flatter in shape than one resulting primarily from a dipole internal field source, but not dissimilar in overall height-to-width configuration to that of the magnetopause calculated for the larger inflated magnetopause observed by Pioneer 10. An array of magnetic field values for locations internal and external to the magnetopause due to currents on the surface has been computed by integrating over the entire magnetopause. A model for the total magnetospheric field of this semi-inflated magnetosphere has been constructed by adding this latter contribution to the internal source fields to obtain a global model of a semi-inflated Jovianlike magnetospheric field. The magnitude of the contribution of the surface currents to the total magnetic field in the region of the orbits of the Galilean satellites is calculated to be considerably larger for this Voyager model than for the Pioneer model.

Engle, I.M. (US Naval Academy, Annapolis, MD (USA))

1991-05-01

220

The Jet Propulsion Laboratory space exploration: Past, present and future  

Microsoft Academic Search

The most recent scientific results from space exploration carried out by the Jet Propulsion Laboratory (JPL) are discussed. To aid understanding of these results, a brief background of JPL's history is presented, followed by a description of the Deep Space Network, JPL's system of antennas which communicates with spacecraft. The results from the missions of Voyager 1 and Voyager 2

Josette Bellan

1993-01-01

221

The Jet Propulsion Laboratory space exploration - Past, present and future  

Microsoft Academic Search

Attention is given to the most recent scientific results from space exploration carried out by JPL. A brief background of JPL's history is presented, and the Deep Space Network, JPL's system of antennas which communicates with spacecraft, is described. Results from the missions of Voyager 1 and Voyager 2 are discussed. Consideration is given to the atmosphere, rings, satellites, and

Josette Bellan

1993-01-01

222

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

NASA Technical Reports Server (NTRS)

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

Statler, Irving C.

1991-01-01

223

Probing Titan's atmosphere by stellar occultation  

Microsoft Academic Search

Results from the first stellar occultation by Titan ever observed, of the bright star 28 Sagitarii, are reported. The event was used to probe Titan's atmosphere in an altitude range of about 250-500 km, where until now there has been an 'information gap' between infrared and ultraviolet Voyager observations, and the results are reported. A central flash was detected as

B. Sicardy; A. Brahic; C. Ferrari; D. Gautier; J. Lecacheux; E. Lellouch; F. Roques; J. E. Arlot; F. Colas; W. Thuillot; F. Sevre; J. L. Vidal; C. Blanco; S. Cristaldi; C. Buil; A. Klotz; E. Thouvenot

1990-01-01

224

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

225

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

NASA Astrophysics Data System (ADS)

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

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

2010-01-01

226

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

PubMed

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

Lapshin, Rostislav V

2009-06-01

227

Voyager 2 at Neptune - Imaging science results  

NASA Technical Reports Server (NTRS)

Neptune's atmosphere is revealed by Voyager 2 images to contain clouds of methane ice above a lower deck of hydrogen sulfide or ammonia ices, and to be dominated by an anticyclonic storm system designated the 'Great Dark Spot'; this bears both similarities and differences to the Great Red Spot of Jupiter. Like the rings of Uranus, those of Neptune are composed of very dark, but in addition very dusty, material. Six new regular satellites have been discovered whose radii range from 25 to 200 km. Triton is noted to be a differentiated body showing evidence of early surface-melting episodes. At least two active plumes are found on Triton, which may be driven by solar heating.

Smith, B. A.; Soderblom, L. A.; Banfield, D.; Barnet, C.; Beebe, R. F.; Bazilevskii, A. T.; Bollinger, K.; Boyce, J. M.; Briggs, G. A.; Brahic, A.

1989-01-01

228

Voyager 1 Jupiter Southern Hemisphere Movie  

NASA Technical Reports Server (NTRS)

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

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

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

2000-01-01

229

Voyager imaging experiment. [for planetary reconnaissance  

NASA Technical Reports Server (NTRS)

The Voyager imaging experiment, which involves two independently operated television systems (a narrow- and a wide-angle camera), is designed to conduct investigations of the atmospheres and surface properties of Jupiter, Saturn, their satellites and Saturn's rings. Objects of the investigations include the horizontal and vertical structure of visible clouds, the vertical structure of high, optically thin scattering layers on Jupiter and Saturn, the Great Red Spot, the South Equatorial Belt, chromophores on Io and Titan, the geology of several satellites, the masses, spin axes and periods of rotation of several satellites, the radial distribution of material in Saturn's rings, and the optical scattering properties of the primaries, rings, and satellites at a variety of wavelengths and phase angles.

Smith, B. A.; Briggs, G. A.; Danielson, G. E.; Cook, A. F., II; Davies, M. E.; Hunt, G. E.; Masursky, H.; Soderblom, L. A.; Owen, T. C.; Sagan, C.

1977-01-01

230

Voyager engineering improvements for Uranus encounter  

NASA Technical Reports Server (NTRS)

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

Marderness, H. P.

1986-01-01

231

Voyages and Travels: Ancient and Modern  

NSDL National Science Digital Library

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

232

Voyager 2 radio observations of Uranus  

NASA Technical Reports Server (NTRS)

Voyager 2 detected continuous radio signals in the 40-100 kHz interval starting from 5 days before passage of Uranus. The radio signals reached 800 kHz within 4 days of closest approach and continued throughout the outward bound phase of flight. The signals were modulated with a period close to 17.24 days, the same period calculated for the rotation of the Uranus magnetosphere with other spacecraft data. The planet was also found to have an off-center magnetic field, and radio signals were strongest when the dipole center was on the nightside of Uranus. Dynamic spectral and burst events which were recorded indicated that Uranus, like the earth, has a strongly defined plasmasphere. It moves under the control of magnetic force tubes that interact with the magnetosphere boundary, producing a variety of MHD phenomena.

Warwick, J. W.; Evans, D. R.; Romig, J. H.; Sawyer, C. B.; Desch, M. D.; Kaiser, M. L.; Alexander, J. K.; Gulkis, S.; Poynter, R. L.

1986-01-01

233

EarthScope Voyager: Did You Know?  

NSDL National Science Digital Library

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

234

Voyager Photometry of Saturn's A Ring  

NASA Technical Reports Server (NTRS)

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 radiative transfer code that includes the illumination of the rings by the Sun and Saturn. The particles in the inner and mid-A Ring have Bond albedos near 0.5 and are more backscattering than satellites of comparable albedo. The region outside the Encke Gap becomes progressively less backscattering with increasing radius. Particle properties change abruptly outside the Keeler Gap; particles here have an albedo near 0.6 and a Lambert-like phase function. In contrast with previous suggestions, the abundance of free, submicrometer "dust" is small throughout the entire A Ring; this conclusion holds even in the outermost A Ring, which is strongly perturbed by density waves. Models derived from low-phase data, assuming only macroscopic particles, correctly predict the highphase reflectivity of the outer A Ring and individual strong density waves in the mid-A Ring. However, the inner and mid-A Ring are typically darker at high phase by a factor of two than our models predict. This discrepancy may be due to the reduced multiple scattering from a layer in which the particles are more closely packed. We have also studied the quadrupole azimuthal brightness asymmetry of the A Ring. The asymmetry has a full amplitude of 35% in the mid-A Ring in low-phase Voyager 2 images. We present results on its behavior and possible implications for the structure of the rings. Finally, we compare our results with studies using other data sets to synthesize our current understanding of the nature of the A Ring.

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

1993-01-01

235

1985 Voyager 2 Radio Ranging Measurements of Coronal Density: Asymmetry in the Radial Profiles Explained  

NASA Technical Reports Server (NTRS)

An asymmetry in the radial variation of electron density above the cast and west limbs of the Sun was inferred from centimeter wavelength ranging measurements conducted by Voyager 2 during its 1985 solar conjunction. The Voyager 2 ranging measurements, which took place in the heliocentric distance range of 7-40 solar radius, have been compared with the white-light coronagraph measurements of the underlying corona collected by the Mark 3 K-coronameter located at the Mauna Loa Solar Observatory. It is shown that the disparity in radial profiles is not real but is instead caused by longitudinal variations stemming from the probing of significantly different source regions its revealed in the white-light measurements. These results improve our understanding of the probing abilities of ranging measurements and their relationship to white-light measurements. They reinforce the notion that the high-precision and high-sensitivity features of ranging measurements are more fully exploited in the investigation of density variations across the ubiquitous low-contrast raylike structures that permit the corona, rather than in determining radial density profiles.

Woo, Richard

1996-01-01

236

Radioisotope Thermoelectric Power Systems: Enabling Technology for European Space Exploration Missions  

NASA Astrophysics Data System (ADS)

Radioisotope power systems (RPS) have proved critical enablers for many of the most demanding space and planetary science missions. US systems, fuelled by 238Pu, have returned extraordinary science from missions such as the Pioneer and Voyager probes, Galileo (Jupiter) and Cassini (Saturn). At the time of writing, New Horizons and Mars Science Laboratory are en route to Pluto and Mars respectively and are equipped with Radioisotope Thermoelectric Generators (RTG). RPSs can provide electrical power to spacecraft systems independently of solar energy, permitting more capable and productive spacecraft and missions. Europe is focused on developing 241Am powered RPSs.

Williams, H. R.; Ambrosi, R. M.; Bannister, N. P.; Samara-Ratna, P.; Tinsley, T. P.; Rice, T.; Sarsfield, M. J.; Cordingley, L.; Slade, R.; Deacon, T.; Jorden, A.; Johnson, W.; Stephenson, K.

2012-09-01

237

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

SciTech Connect

Voyager 2 data from the Plasma Science experiment, the Magnetometer experiment and the Planetary Radio Astronomy experiment were used to analyze the relationship between parameters of the solar wind/interplanetary medium and the nonthermal Saturn radiation. Solar wind and interplanetary magnetic field properties were combined to form quantities known to be important in controlling terrestrial magnetospheric processes. The Voyager 2 data set used in this investigation consists of 237 days of Saturn preencounter measurements. However, due to the immersion of Saturn and the Voyager 2 spacecraft into the extended Jupiter magnetic tail, substantial periods of the time series were lacking solar wind data. To cope with this problem a superposed epoch method (CHREE analysis) was used. The results indicate the superiority of the quantities containing the solar wind density in stimulating the radio emission of Saturn - a result found earlier using Voyager 1 data - and the minor importance of quantities incorporating the interplanetary magnetic field. 10 references.

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

1985-01-01

238

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

239

NASA Facts: Images of Saturn from Voyager 2  

NASA Technical Reports Server (NTRS)

Six color images of Saturn and four of her moons, acquired by Voyager 2, are presented. A brief narrative and explanatory captions, including explanations of the planet's atmosphere and rings, are presented.

1981-01-01

240

Voyager flight project: DSN Telecommunications Compatibility Test Program  

NASA Technical Reports Server (NTRS)

The Voyager Flight Project - DSN Telecommunications Compatibility Test Program consisted of three phases: Subsystem Design, System Design, and System Verification Tests. Subsystem Design Tests were performed during mid 1976. System Design Tests were performed during late 1976 and early 1977. System Verification Tests were performed during the spring and summer of 1977. This article describes the System Design Tests and test results that provided the basis for establishment of telecommunications design between the DSN and the Voyager Flight Project.

Bryan, A. I.; Kemp, R. P.; Madsen, B. D.

1977-01-01

241

IUE/Voyager observations of luminous accretion disk systems  

NASA Technical Reports Server (NTRS)

The importance of simultaneous IUE and Voyager observations of luminous accretion disk systems is shown. The composite spectra of SS Cyg, VW Hyi, CPD-48 1577, and V3895 Sgr show the changes which occur in the continuum flux distributions from 3200 A down to the Lyman limit. Results imply that current disk ingredients (i.e., blackbodies and Kurucz atmospheres) cannot explain the IUE/Voyager observations.

Carone, T. E.; Polidan, R. S.; Wade, R. A.

1986-01-01

242

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

NASA Technical Reports Server (NTRS)

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

Pavlis, Erricos C.

1992-01-01

243

Probing the parameter space for an MSSM inflation and the neutralino dark matter  

SciTech Connect

The flat directions LLe and udd within the minimal supersymmetric standard model provide all the necessary ingredients for a successful inflation with the right amplitude of the scalar density perturbations, negligible gravity waves and the spectral tilt within 2{sigma} observed range 0.92{<=}n{sub s}{<=}1.0. In this paper we explore the available parameter space for inflation in conjunction with a thermal cold dark matter abundance within the minimal supergravity model. Remarkably for the inflaton, which is a combination of squarks and sleptons, there is a stau-neutralino coannihilation region below the inflaton mass 500 GeV for the observed density perturbations and the tilt of the spectrum. For such a low mass of the inflaton the LHC is capable of discovering the inflaton candidates within a short period of its operation. Inflation is also compatible with the focus point region which opens up for the inflaton masses above TeV. We show that embedding MSSM within SO(10) can naturally favor this region.

Allahverdi, Rouzbeh [Perimeter Institute for Theoretical Physics, Waterloo, ON, N2L 2Y5 (Canada); Dutta, Bhaskar [Department of Physics, Texas A and M University, College Station, Texas 77843-4242 (United States); Mazumdar, Anupam [NORDITA, Blegdamsvej-17, Copenhagen-2100 (Denmark)

2007-04-01

244

Tone-Based Command of Deep Space Probes using Ground Antennas  

NASA Technical Reports Server (NTRS)

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

Bokulic, Robert S.; Jensen, J. Robert

2008-01-01

245

Spectral analysis of groove spacing on Ganymede  

NASA Technical Reports Server (NTRS)

The technique used to analyze groove spacing on Ganymede is presented. Data from Voyager images are used determine the surface topography and position of the grooves. Power spectal estimates are statistically analyzed and sample data is included.

Grimm, R. E.

1984-01-01

246

The helium abundance of Jupiter from Voyager  

NASA Technical Reports Server (NTRS)

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

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

1980-01-01

247

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

NASA Technical Reports Server (NTRS)

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

Henry, Richard C.

1994-01-01

248

Voyager 2 observations of plasma in the heliosheath  

NASA Astrophysics Data System (ADS)

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

Richardson, J. D.

2011-12-01

249

Voyager 1 Observations of Rapid Changes in the Heliosheath  

NASA Astrophysics Data System (ADS)

For the last eight and five years respectively, Voyager 1 and 2 have been exploring the spatial and dynamical properties of heliosheath. In April 2010, Voyager 1 entered a quasi-stagnation region at 113 AU in the northern heliosheath, with a slow flow speed, enhanced magnetic field, and long term changes in the intensities of termination shock particles, anomalous cosmic rays, and galactic cosmic ray electrons and nucleons. Recently, more rapid changes indicate further evolution in the region beyond 121 AU as Voyager 1 observed a 10% increase in cosmic rays with greater than 70 MeV over a four week period beginning May 7, 2012. An even more abrupt decrease of 50% in the intensity of Termination Shock Particles with greater than 0.5 MeV was observed on July 28 at 121 AU, followed by an equally rapid recovery on August 1. In contrast, at 99 AU in the southern heliosheath Voyager 2 finds the flow is faster and turning to flow tail ward, with more gradual changes in particle intensities. An overview of these observations and any further changes as Voyager 1 approaches the heliopause will be presented.

Stone, E. C.

2012-12-01

250

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

251

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

252

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

Code of Federal Regulations, 2012 CFR

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

2012-07-01

253

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

254

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

NASA Technical Reports Server (NTRS)

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

Hartman, William; Koontz, Steven L.

2010-01-01

255

Investigating the heliospheric ion suprathermal tail with Voyager LECP data  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

256

[Central hemodynamics in seamen during trans-latitudinal voyage].  

PubMed

The present study has analyzed a cardiovascular response in the sailors of a ship's crew (n = 23) on board the large self-reacting trawler "Konstantin Dushenov" during a fish-catching translatitudinal voyage for 5 months (181 days). The nonspecific mechanisms of adaptation in the seamen during long-term voyages are found to form by activating the central outlines of controlling. With the general trend for the activity of the sympathetic nervous system to decrease during the voyage, latter manifested itself under loads in a working cycle, by demonstrating the preserved responsiveness of the body in the sailors. By analyzing the results of the study, the authors show that there are the correlations between the parameters kept in mind, which allow the mechanisms of adjustment to be studied. The paper presents the results of informational simulation of correlation matrices with their high level of generalization where the time of course of adaptive changes to working conditions is demonstrated. PMID:15017880

Myznikov, I L; Shcherbina, F A

2004-01-01

257

A Voyager attitude control perspective on fault tolerant systems  

NASA Technical Reports Server (NTRS)

In current spacecraft design, a trend can be observed to achieve greater fault tolerance through the application of on-board software dedicated to detecting and isolating failures. Whether fault tolerance through software can meet the desired objectives depends on very careful consideration and control of the system in which the software is imbedded. The considered investigation has the objective to provide some of the insight needed for the required analysis of the system. A description is given of the techniques which have been developed in this connection during the development of the Voyager spacecraft. The Voyager Galileo Attitude and Articulation Control Subsystem (AACS) fault tolerant design is discussed to emphasize basic lessons learned from this experience. The central driver of hardware redundancy implementation on Voyager was known as the 'single point failure criterion'.

Rasmussen, R. D.; Litty, E. C.

1981-01-01

258

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

2013-09-27

259

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 ± 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

260

46 CFR 14.309 - Entries in shipping articles at end of voyage.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Entries in shipping articles at end of voyage. 14.309 Section... § 14.309 Entries in shipping articles at end of voyage. (a) At the end of each voyage upon which shipping articles are required, the master or...

2013-10-01

261

Performance of differenced range data types in Voyager navigation  

NASA Technical Reports Server (NTRS)

Voyager radio navigation made use of differenced range data type for both Saturn encounters because of the low declination singularity of Doppler data. Nearly simultaneous two-way range from two-station baselines was explicitly differenced to produce this data type. Concurrently, a differential VLBI data type (DDOR), utilizing doubly differenced quasar-spacecraft delays, with potentially higher precision was demonstrated. Performance of these data types is investigated on the Jupiter to Saturn leg of Voyager 2. The statistics of performance are presented in terms of actual data noise comparisons and sample orbit estimates. Use of DDOR as a primary data type for navigation to Uranus is discussed.

Taylor, T. H.; Campbell, J. K.; Jacobson, R. A.; Moultrie, B.; Nichols, R. A., Jr.; Riedel, J. E.

1982-01-01

262

Voyager 2 at Uranus - A synopsis of atmospheric science results  

NASA Technical Reports Server (NTRS)

Knowledge of the Uranian atmosphere took a quantum leap when the Voyager 2 spacecraft made a close approach in January 1986. Among the highlights of the early results are measurements of the atmospheric composition (He mole fraction = 0.15; Ch4 mole fraction = 0.02), rotation period of the deep interior (17.24 h), thermal structure and dynamics (the planet is coldest at midlatitudes; retrograde equatorial winds are inferred), and upper-atmosphere processes (a phenomenon called electroglow is only partly understood and is recognized as an important process n all the major-planet atmospheres examined by Voyager).

West, Robert A.

1987-01-01

263

Energetic Particle Measurements from Voyager 1 in the Heliosheath  

NASA Astrophysics Data System (ADS)

Voyager 1 encountered the solar wind termination shock (TS) on day 351 of 2004 (94.0 AU, N34°) and entered the heliosheath. Since that time until at least day 248 of 2005 (96.6 AU), observations indicate that the spacecraft has remained in the heliosheath. We will describe intensities and angular distributions of ions >40 keV and electrons >26 keV measured during 2005 by the Low Energy Charged Particle instruments on Voyagers 1 and 2. Notable features observed thus far in the heliosheath particle data from Voyager 1 include: (1) high, slowly rising, and relatively smooth intensities devoid of the large (factors ~5-10), frequent (~26 days) fluctuations that characterized intensities upstream of the TS; (2) large reductions in the amplitude and occurrence rates of the anti-sunward, near-azimuthal beaming anisotropies that were routinely seen in the pre-TS ion data; and, (3) radial plasma flow speeds, estimated from analysis of low-energy ion angular distributions, that have ranged over ~+100 km/s (2004.95-2005.04), ~-50 to 0 km/s (2005.04-2005.30), ~0 to +50 km/s (2005.3-2005.46), and most recently ~+50 to +100 km/s (2005.46-2005.66). For about the first 0.5 year after the TS crossing (2004.95), intensities of protons 40 to ~500 keV remained relatively flat, while those of protons >500 keV increased steadily. Starting around 2005.45, however, intensities of the lower energy protons also began increasing, and in the recent data, intensities at all energies >40 keV have leveled off. We are fortunate to be currently receiving heliosheath data from Voyager 1 and solar wind data from Voyager 2, which has evidently entered the termination foreshock region. Voyager 2 began observing low intensities of TS precursor protons in late 2004 (75 AU, S26°), and by mid-2005 (77 AU), both the intensity and anti-sunward, near-azimuthal beaming anisotropy of 3-17 MeV protons had reached levels comparable to those observed at Voyager 1 during the latter half of 2002 (85-87 AU). We will discuss further details of these Voyager 1 and 2 observations made in the vicinity of the TS.

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

2005-12-01

264

Astrographic observations of the major Uranian satellites from Voyager 2  

NASA Astrophysics Data System (ADS)

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

Jacobson, R. A.

1992-12-01

265

Voyager Observations of Cosmic Rays at the Edge of the Heliosphere (Invited)  

NASA Astrophysics Data System (ADS)

The twin Voyager spacecraft continue to explore the outermost region of the heliosphere and are returning very different results from their two locations. Voyager 2 is heading south and will be at 103.5 AU and 30.5 degrees S helio-latitude at the time of the meeting. It is continuing to observe a combination of cosmic rays of heliospheric and galactic origin. Voyager 1 (V1), on the other hand, is heading north at 126.2 AU and 34.6 degrees N helio-latitude and for more than a year has been in an unexpected region of space that is completely depleted of energetic heliospheric ions. The V1 data are thus permitting the observation of the galactic cosmic-ray energy spectra to lower energies than ever before. The boundary of this region was crossed on 25 August 2012 and appears in many respects to have been the heliopause, the structure separating the heliospheric and galactic plasmas, except that the direction of the magnetic field did not change, indicating that V1 is still within the realm of the solar magnetic field. The galactic cosmic rays that are observed at V1 may or may not be fully unmodulated, as their distribution shows a significant pitch-angle anisotropy and some models suggest there is modulation beyond the heliopause. Nonetheless, the energy spectra of many elements are in good agreement with calculated local interstellar energy spectra from one of the commonly used GALPROP models. We will report on the latest observations at the meeting. This work was supported by NASA under contract NNN12AA012.

Cummings, A. C.; Stone, E. C.; Heikkila, B.; Lal, N.

2013-12-01

266

Conductivity Probe  

NASA Technical Reports Server (NTRS)

The Thermal and Electrical Conductivity Probe (TECP) for NASA's Phoenix Mars Lander took measurements in Martian soil and in the air.

The needles on the end of the instrument were inserted into the Martian soil, allowing TECP to measure the propagation of both thermal and electrical energy. TECP also measured the humidity in the surrounding air.

The needles on the probe are 15 millimeters (0.6 inch) long.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

2008-01-01

267

Voyager observations of jupiter's distant magnetotail. Progress report  

SciTech Connect

Observations of nonthermal continuum radiation by Voyager 1 and 2 at large distances from Jupiter have led to the identification of brief encounters with the Jovian magnetosphere at distances greater than 700 RJ and in directions substantially far from the Jupiter-Sun line. In addition, a number of examples of continuum radiation apparently trapped in local density depressions in the solar wind are observed. Simultaneous measurements by the Voyager plasma instrument have verified the distant magnetotail crossings and are used to correlate the occurrence of trapped continuum radiation events within solar wind density rarefractions. The Voyager observations of the distant Jovian magnetotail are compared with observations in the distant terrestrial magnetosphere and also with observations of the plasma tails of comets. One variable explanation of the observations is that the Jovian tail consists of filamentary structures, some of which extend to large distances in the pre-dawn direction. The observations of continuum radiation trapped in low-density regions of the solar wind suggest that Voyager may at times be connected to the distant tail by a low-density trough which acts as a wave guide and allows radiation from the tail to reach the spacecraft. This may provide an indirect method of detecting the tail extending more than 2 AU downstream from Jupiter.

Kurth, W.S.; Gurnett, D.A.; Scarf, F.L.; Poynter, R.L.; Sullivan, J.D.

1980-08-01

268

A plasma wave investigation for the Voyager Mission  

Microsoft Academic Search

The Voyager Plasma Wave System (PWS) will provide the first direct information on wave-particle interactions and their effects at the outer planets. The data will give answers to fundamental questions on the dynamics of the Jupiter and Saturn magnetospheres and the properties of the distant interplanetary medium. Basic planetary dynamical processes are known to be associated with wave-particle interactions (for

Frederick L. Scarf; Donald A. Gurnett

1977-01-01

269

Voyager dans l'Antiquité : en guise d'introduction  

Microsoft Academic Search

Depuis quelques décennies, le goût pour l'anthropologie se développe et il favorise l'éclosion de nouveaux thèmes de recherche. « Le voyage » entre dans cette catégorie des sujets qui intéressent de plus en plus aussi bien les chercheurs que les simples curieux et, à ce propos, il faut rappeler qu'un livre de Lionel Casson a joué un rôle précurseur dans

Yann LE BOHEC

270

Voyages of Discovery: Experiencing the Emotion of History  

ERIC Educational Resources Information Center

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

Kelin, Daniel A., II

2005-01-01

271

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

272

Voyager studies of the distant heliospheric magnetic fields and plasmas  

Microsoft Academic Search

Launched in 1977, the twin Voyager spacecraft (V1, V2) are exiting the heliosphere and each one is now well beyond the orbits of the planets. Careful studies have been made of the observed heliospheric magnetic field (HMF) and solar wind plasma over a full solar solar cycle through 2001. At that time, V1 was at a radial distance of 87

N. F. Ness; L. F. Burlaga; J. D. Richardson

2003-01-01

273

Overview of the Voyager Ultraviolet Spectrometry Results Through Jupiter Encounter  

Microsoft Academic Search

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

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

1981-01-01

274

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

275

Orbital Dynamics of the Uranian Satellites Based on Voyager Data.  

National Technical Information Service (NTIS)

The satellites of Uranus all have significant non-zero eccentricities and in the case of Miranda a significant inclination as well. The Voyager 2 encounter with Uranus in January 1986, provided more accurate estimates of the masses and sizes of the satell...

J. B. Plescia

1987-01-01

276

The Voyager 2 encounter with the Uranian system  

Microsoft Academic Search

Discoveries which have occurred due to the success of the Voyager 2 flyby of Uranus and its moons are summarized, along with techniques used to maximize the data collected and minimize the demands on the spacecraft. The 11 spacecraft science packages, including photopolarimeters, spectrometers, a magnetometer, radios and a charged particle detector gathered information on the ring system, the scattering,

E. C. Stone; E. D. Miner

1986-01-01

277

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

278

Magnetic field studies by Voyager 2 - Preliminary results at Saturn  

NASA Astrophysics Data System (ADS)

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

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

1982-01-01

279

The Jupiter system through the eyes of Voyager 1  

Microsoft Academic Search

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

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

1979-01-01

280

Whistlers observed by Voyager 1: Detection of lightning on Jupiter  

Microsoft Academic Search

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

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

1979-01-01

281

Jupiter plasma wave observations: an initial Voyager 1 overview  

Microsoft Academic Search

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

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

1979-01-01

282

Plasma observations near Saturn - Initial results from Voyager 1  

Microsoft Academic Search

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

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

1981-01-01

283

Encounter with Saturn - Voyager 1 imaging science results  

Microsoft Academic Search

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

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

1981-01-01

284

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

Microsoft Academic Search

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

M. D. Desch; M. L. Kaiser

1981-01-01

285

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

286

Extensible Statistical Software: On a Voyage to Oberon  

Microsoft Academic Search

Recent changes in software technology have opened new possibilities for statistical computing. Conditions for creating efficient and reliable extensible systems have been largely improved by programming languages and systems that provide dynamic loading and type-safety across module boundaries, even at run time. We introduce Voyager, an extensible data analysis system based on Oberon, which tries to exploit some of these

Günther Sawitzki

1996-01-01

287

Extensible Statistical Software: On a Voyage to Oberon  

Microsoft Academic Search

Recent changes in software technology have opened new possibilities for statistical computing. Conditions for creating efficient and reliable extensible systems have been largely improved by programming languages and systems which provide dynamic loading and type-safety across module boundaries, even at run time. We introduce Voyager, an extensible data analysis system based on Oberon, which tries to exploit some of these

Günther Sawitzki; StatLab Heidelberg

1995-01-01

288

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

289

Voyager 1 planetary radio astronomy observations near Jupiter  

Microsoft Academic Search

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

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

1979-01-01

290

Planetary radio astronomy observations from Voyager 1 near Saturn  

Microsoft Academic Search

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

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

1981-01-01

291

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

292

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

293

Voyager 1 Observations of Galactic Cosmic Rays in the Local Interstellar Medium  

NASA Astrophysics Data System (ADS)

The twin Voyager spacecraft were launched in 1977 and continue to be on a remarkable journey of exploration. Both spacecraft have crossed the termination shock of the solar wind and Voyager 1 (V1) crossed into interstellar space in ~mid-2012. At that crossing of the heliopause, the particles of heliospheric origin that had dominated the energy spectrum of most cosmic ray nuclei below approximately 50 MeV/nucleon disappeared, revealing for the first time the energy spectra of galactic cosmic rays (GCRs) down to about 3 MeV/nucleon. The intensity of GCRs has not shown any significant long-term gradient since the crossing, suggesting that V1 is observing the energy spectra of GCRs in the local interstellar medium unaffected by solar modulation. The energy spectra of H, He, C, and O have rather broad peaks in the ~20-100 MeV/nucleon energy range. The H/He ratio in this energy range is ~12 and that of C/O is ~1. We are also observing the local interstellar electron spectrum and find that a power-law energy dependence with spectral index approximately -1.5 from ~5-70 MeV is consistent with the data. We will report on the latest observations at the meeting. This work was supported by NASA under contract NNN12AA012.

Cummings, Alan; Stone, Edward C.; Heikkila, Bryant; Lal, Nand; Webber, William R.

2014-08-01

294

Real-space imaging of molecular structure and chemical bonding by single-molecule inelastic tunneling probe.  

PubMed

The arrangement of atoms and bonds in a molecule influences its physical and chemical properties. The scanning tunneling microscope can provide electronic and vibrational signatures of single molecules. However, these signatures do not relate simply to the molecular structure and bonding. We constructed an inelastic tunneling probe based on the scanning tunneling microscope to sense the local potential energy landscape of an adsorbed molecule with a carbon monoxide (CO)-terminated tip. The skeletal structure and bonding of the molecule are revealed from imaging the spatial variations of a CO vibration as the CO-terminated tip probes the core of the interactions between adjacent atoms. An application of the inelastic tunneling probe reveals the sharing of hydrogen atoms among multiple centers in intramolecular and extramolecular bonding. PMID:24855265

Chiang, Chi-lun; Xu, Chen; Han, Zhumin; Ho, W

2014-05-23

295

Deep space communication - Past, present, and future  

Microsoft Academic Search

This paper reviews the progress made in deep space communication from its beginnings until now, describes the development and applications of NASA's Deep Space Network, and indicates directions for the future. Limiting factors in deep space communication are examined using the upcoming Voyager encounter with Uranus, centered on the downlink telemetry from spacecraft to earth, as an example. A link

E. C. Posner; R. Stevens

1984-01-01

296

Voyagers and voyeurs: Supporting asynchronous collaborative visualization  

Microsoft Academic Search

This article 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

2009-01-01

297

Voyages of Discovery through a Backpack Exchange  

ERIC Educational Resources Information Center

Backpacks are commonplace in American schools. Each day students transport them to and from the classroom as they manage to carve out a little oasis of space to gather their treasures, homework and books. In Fair Lawn's recently launched Chinese classes, backpacks take on new responsibility, becoming culture bearers that connect middle school…

Syz, Tracy Hong

2008-01-01

298

Continuing the Voyage: The Spirit of Endeavour.  

National Technical Information Service (NTIS)

The exploration and development of the space frontier is the most technically challenging endeavor of our generation and there are many to follow. In carrying forward with this mission, we are building on the exploits of our forbears in their own missions...

M. D. Griffin

2008-01-01

299

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

NASA Technical Reports Server (NTRS)

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

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

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

1996-01-01

300

Plasma waves near Saturn: initial results from Voyager 1  

SciTech Connect

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

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

1981-01-01

301

The galilean satellites and Jupiter: Voyager 2 imaging science results  

USGS Publications Warehouse

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

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

1979-01-01

302

Voyager uplink planning in the interstellar mission era  

NASA Technical Reports Server (NTRS)

The Voyager Project has entered its last phase of discovery--the Voyager Interstellar Mission (VIM). Because of the reduced scope of the project and a lower budget, new ways had to be developed to program two spacecraft with fewer people and to allow for some sequence development flexibility without additional risk. In the previous cruise era, it took a seven-person sequence team 12 weeks to develop a nominal eight week cruise sequence. Today it takes a three-person team six weeks to develop a 13 week sequence load. This paper will describe in detail the sequencing strategy which reduces the volume and frequency of sequence loads, and the new tools and processes developed which reduce the manual effort required to generate these sequences without adding risk.

Linick, Susan H.; Weld, Kathryn R.

1993-01-01

303

VOYAGER 2 OBSERVES A LARGE DENSITY INCREASE IN THE HELIOSHEATH  

SciTech Connect

Voyager 2 (V2) entered the heliosheath in 2007 August at roughly the same time solar minimum conditions were reaching the outer heliosphere. Soon after crossing the termination shock the solar wind density at Voyager decreased by a factor of two and the temperature decreased by a factor of three. At the beginning of 2011 the plasma density in the heliosheath began to increase and in mid-2012 it was up by more than a factor of two. The temperature rose by about 50% and the speed remained constant, although the flow direction continues to turn tailward. These changes may signal the end of solar minimum conditions at V2 in the heliosheath, although we do not understand why the speed did not decrease. The increased dynamic pressure has lead to an outward movement of the termination shock from its very compressed state at solar minimum.

Richardson, J. D. [Kavli Center for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Wang, C., E-mail: jdr@space.mit.edu, E-mail: cw@spaceweather.ac.cn [State Key Laboratory for Space Weather, Chinese Academy of Sciences, Beijing (China)

2012-11-01

304

Voyager 2 - Energetic ions and electrons in the Jovian magnetosphere  

NASA Technical Reports Server (NTRS)

The passage of Voyager 2 through the Jovian magnetosphere demonstrated that this magnetosphere is highly variable, even as close as 10 Jupiter radii from the planet. The cosmic-ray subsystem measured the flux, elemental composition, and anisotropy of energetic particles. Its high sensitivity was particularly valuable during the long passage through the magnetotail, where particle fluxes were orders of magnitude less than in the inner magnetosphere and approached interplanetary values. The new data confirm earlier observations that the Jovian magnetosphere is a giant accelerator of particles - electrons, protons, and heavy ions, including sulfur. Both spatial and temporal changes are observed in the magnetosphere as compared to prior observations with Pioneer 10 and 11 and Voyager 1. It is suggested that the 10-hr modulation of interplanetary Jovian electrons may be associated with the arrival at the dawn magnetopause of a rarefaction region each planetary rotation.

Vogt, R. E.; Cummings, A. C.; Garrard, T. L.; Gehrels, N.; Stone, E. C.; Trainor, J. H.; Schardt, A. W.; Conlon, T. F.; Mcdonald, F. B.

1979-01-01

305

The European Voyages of Exploration: The Fifteenth and Sixteenth Centuries  

NSDL National Science Digital Library

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

Chastko, Paul.; Lalonde, Vicki.

306

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.

307

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

308

Voyager 2 at Uranus - A synopsis of atmospheric science results  

Microsoft Academic Search

Knowledge of the Uranian atmosphere took a quantum leap when the Voyager 2 spacecraft made a close approach in January 1986. Among the highlights of the early results are measurements of the atmospheric composition (He mole fraction = 0.15; Ch4 mole fraction = 0.02), rotation period of the deep interior (17.24 h), thermal structure and dynamics (the planet is coldest

Robert A. West

1987-01-01

309

Voyager Observations of Cosmic Rays in the Heliosheath  

NASA Astrophysics Data System (ADS)

Since crossing the termination shock in 2004.95 (94AU 36°N), Voyager 1 has penetrated some 24 AU into the heliosheath over a period that now extends from near solar maximum conditions to the onset of the cycle 24 modulation at 1AU in ~ 2010. Voyager 2 entered the heliosheath in 2007.66 (83.7 AU, 27.5°S). Over the period 2006.0-2011.5 the V1/V2 265MeV/n galactic cosmic ray (GCR) He has increased at an average rate of 6.3% /year with an instanteous radial gradient of 0.2 ± 0.2%/AU. The rate of increase of 265 MeV/n H is 14%/year and 10 MeV GCR electrons increased at 55%/year. While the GCR intensities were increasing, the 15 MeV/n and 43 MeV/n ACR He at V1 began a slow decrease in 2009 that is becoming moderately steeper with time suggesting the spacecraft may be entering the region of higher magnetic fields expected near the heliopause. In 2011 the V1 GCR carbon spectra between 20 and 80 MeV/n has a slope of 1 as would be expected if the heliosheath functions as a long term storage region for GCRs with occasional forays into the region of the supersonic solar wind where they experience adiabatic energy losses. An alternate interpretation would be that their low-energy local interstellar spectrum is quite different from what was expected. Heliosheath transient increases are observed at the Voyagers, generally involving GCR ions and electrons and ACRs and which can persist for almost a year. The trigger for these events is not known at this time. The Voyager observations are establishing that at energies below ~ 1 GeV, the heliosheath is a vital, complex part of the cosmic ray dynamics in our solar system.

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

2011-12-01

310

Infrared observations of the Saturnian system from Voyager 1  

Microsoft Academic Search

Atmospheric chemistry analyses of Saturn based on Voyager 1 infrared spectral and radiometric data are presented, including characteristics of the planet's rings and of Titan and other satellites. Infrared spectra of Saturn indicate the presence of H2, CH4, NH3, PH3, C2H2, and C2H6, with the possibility of C3H4 and C3H8. The atmospheric thermal structure of the planet shows hemispheric asymmetries

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

1981-01-01

311

Extreme ultraviolet observations from Voyager 1 encounter with Jupiter  

Microsoft Academic Search

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

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

1979-01-01

312

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

Microsoft Academic Search

Evidence for a marginal detection of the Titan ionosphere has been obtained from a new analysis of the dual-frequency Doppler data recorded during theVoyager 1occultation in 1980. The original report by Lindalet al.(1983,Icarus53,348–363) gave only upper bounds on the peak electron density of 3000 cm?3during ingress (evening terminator) and 5000 cm?3during egress (morning terminator). The dual-frequency ingress data imply a

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

1997-01-01

313

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

Microsoft Academic Search

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

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

1997-01-01

314

Mapping the Galilean satellites of Jupiter with Voyager data.  

USGS Publications Warehouse

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

Batson, R. M.

1980-01-01

315

Analysis of Voyager images of Europa - plasma bombardment  

Microsoft Academic Search

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

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

1988-01-01

316

Energetic charged particles in Saturn's magnetosphere: Voyager 2 results  

Microsoft Academic Search

Results from the cosmic-ray system on Voyager 2 in Saturn's magnetosphere are presented. During the inbound pass through the outer magnetosphere, the greater than or equal to 0.43-million-electron-volt proton flux was more intense, and both the proton and electron fluxes were more varible, than previously observed. These changes are attributed to the influence on the magnetosphere of variations in the

R. E. Vogt; D. L. Chenette; A. C. Cummings; T. L. Garrard; E. C. Stone; A. W. Schardt; J. H. Trainor; N. Lal; F. B. McDonald

1982-01-01

317

Voyager Observations of Diffuse Ultraviolet Light Shortward of Lyman ?  

NASA Astrophysics Data System (ADS)

The results of seventeen years of Voyager observation of diffuse ultraviolet background radiation have been reported by Murthy et al. (1999, ApJ, 522, 904). The most important result is that there are discovered to be large numbers of locations on the sky, at all galactic latitudes, where the diffuse background is not detected at all, with an upper limit, in the best cases, of 30 photons cm-2 s-1 sr-1 ÅBut, there are also many locations, and again at all galactic latitudes, where a considerable flux of ultraviolet light is seen. We present a map showing the locations and brightnesses of these positive detections, and we exhibit typical spectra. At the moment, the nature of the emitting diffuse objects is not understood, except that, since these objects are observed to occur at low galactic latitudes (as well as at high galactic latitudes), they can hardly be extragalactic in nature. The Voyager ultraviolet spectrometers have a field of view that is 0.1^circ × 0.87^circ. Murthy et al. used Voyager spacecraft jitter as a means of excluding observations that could be attributed to a point source in the field of view. The spectral range of the observations is from well below the interstellar gas photoionization edge at 912 Å (which is detected), through Lyman alpha at 1216 Åand continuing (but with much lower sensitivity) to 1700 Å

Conn Henry, Richard; Murthy, Jayant; Hoberg, Jay B.

2002-04-01

318

Planetary radio astronomy observations from Voyager 2 near Saturn  

NASA Technical Reports Server (NTRS)

Planetary radio astronomy measurements obtained by Voyager 2 near Saturn have added further evidence that Saturnian kilometric radiation is emitted by a strong dayside source at auroral latitudes in the northern hemisphere and by a weaker source at complementary latitudes in the southern hemisphere. These emissions are variable because of Saturn's rotation and, on longer time scales, probably because of influences of the solar wind and Dione. The electrostatic discharge bursts first discovered by Voyager 1 and attributed to emissions from the B ring were again observed with the same broadband spectral properties and an episodic recurrence period of about 10 hours, but their occurrence frequency was only about 30 percent of that detected by Voyager 1. While crossing the ring plane at a distance of 2.88 Saturn radii, the spacecraft detected an intense noise event extending to above 1 megahertz and lasting about 150 seconds. The event is interpreted to be a consequence of the impact, vaporization, and ionization of charged, micrometer-size G ring particles distributed over a vertical thickness of about 1500 kilometers.

Warwick, J. W.; Evans, D. R.; Romig, J. H.; Alexander, J. K.; Desch, M. D.; Kaiser, M. L.; Aubier, M.; Leblanc, Y.; Lecacheux, A.; Pedersen, B. M.

1982-01-01

319

Abundances of Jupiter's Trace Hydrocarbons from Voyager and Cassini  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

320

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

321

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

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

322

NASA utilization of the International Space Station and the Vision for Space Exploration  

Microsoft Academic Search

In response to the US President's Vision for Space Exploration (January 14, 2004), NASA has revised its utilization plans for International Space Station (ISS) to focus on (1) research on astronaut health and the development of countermeasures that will protect our crews from the space environment during long-duration voyages, (2) ISS as a test bed for research and technology developments

Julie A. Robinson; Tracy L. Thumm; Donald A. Thomas

2007-01-01

323

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

324

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

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

325

The Local Interstellar Spectrum beyond the Heliopause: What can be Learned from Voyager in the Inner Heliosheath?  

NASA Astrophysics Data System (ADS)

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 & 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 & 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 1026 to 1027 cm2 s-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.; Steinhilber, F.

2012-12-01

326

The Local Interstellar Spectrum Beyond the Heliopause: What can we Learn from Voyager in the Inner Heliosheath?  

NASA Astrophysics Data System (ADS)

The local interstellar spectrum (LIS) is one of the most important but unknown parameters in all model efforts to describe the modulation of Galactic Cosmic Rays on their way from the galaxy through a possible bow shock, heliosheath and heliosphere towards the Earth. Because it could not be measured so far, several LIS models derived from numerical simulations or data at Earth were developed. A new perspective to determine the LIS was opened when the Voyager spacecraft crossed the termination shock and entered the heliosheath. \\citet{Webber-Higbie-2009} derived a new LIS, which is lower than all previous LIS models over the entire energy range, on the base of these measurements. Numerical simulations by \\citet{Scherer-etal-2011} showed that already particles in the outer heliosheath are modulated, suggesting that the LIS by \\citet{Webber-Higbie-2009} is a heliopause spectrum rather than the ``true'' LIS. By using textbf{the same simplified simulation model} we estimate the diffusion coefficient in the OHS to be consistent with several 1026 to 1027 cm2 s-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 next future. We then discuss the circumstance under which terrestrial archive can be used to at least exclude LIS models unless one has to await a dedicated mission like e.g. the Interstellar Probe.

Kopp, A.; Herbst, K.; Heber, B.

2012-12-01

327

Net current measurements and secondary electron emission characteristics of the Voyager plasma science experiment and their impact on data interpretation  

NASA Technical Reports Server (NTRS)

The Voyager Plasma Science (PLS) instrument is capable of returning integral (DC) current measurements, similar in some respects to measurements made with a Langmuir probe or a retarding potential analyzer, although there are significant differences. The integral measurements were made during a calibration sequence in the solar wind, during Cruise Science Maneuvers, and within the magnetospheres of Jupiter and Saturn by Voyager 1. After the failure of the PLS experiment following the Saturn encounter, that instrument was placed in the DC return mode returning possibly usable data from early 1981 through early 1985. The DC return measurements are difficult to interpret and are above threshold values only for relatively large fluxes; the determination of the measured current level is dependent on the operating temperature of the preamplifiers which further complicates the interpretation. Nevertheless, these measurements can be used to determine the efficiency of the suppressor grid at preventing the loss of secondary electrons off the collector plate. Some DC return measurements have been invaluable in aiding in the interpretation of some electron plasma measurements not previously understood. It is found that electron spectra can be significantly modified by the presence of second generation secondary electrons produced by either first generation secondaries or photoelectrons on the support ring of the negative high voltage modulator grid within the instrument housing.

Mcnutt, Ralph L., Jr.

1988-01-01

328

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 ± 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

329

Femtosecond-laser-induced Ablation of an Aluminum Target Probed by Space- and Time-resolved Soft X-ray Absorption Spectroscopy  

NASA Astrophysics Data System (ADS)

Laser ablation involves phase transitions that produce an ablation plume consisting of various states of matter, namely solid, liquid, vapor, and plasma. This plume plays an important role in the deposition of thin films [1], the formation of nanoparticles [2], and other processes. It is important to investigate this ablation plume at the atomic level not only for a basic study of laser ablation dynamics but also to provide a better understanding of such processes. Because the plume evolves spatially over time, space- and time-resolved measurements are also required. One atomic-level diagnostic method is X-ray absorption spectroscopy (XAS). This involves an element-specific probe of the local structure in a material and provides information about its electronic and atomic structure. An important advantage of this technique is that a wide variety of solid, liquid, and gaseous samples can be examined directly and nondestructively. Furthermore, we can combine this technique with an ultrafast X-ray probe generated by femtosecond-laser-induced plasma [3]-[6], and this makes time-resolved XAS suitable for the study of laser ablation processes.

Okano, Yasuaki; Oguri, Katsuya; Nishikawa, Tadashi; Nakano, Hidetoshi

330

Estimating the Deep Space Network modification costs to prepare for future space missions by using major cost drivers  

NASA Technical Reports Server (NTRS)

This paper develops a cost model to do long range planning cost estimates for Deep Space Network (DSN) support of future space missions. The paper focuses on the costs required to modify and/or enhance the DSN to prepare for future space missions. The model is a function of eight major mission cost drivers and estimates both the total cost and the annual costs of a similar future space mission. The model is derived from actual cost data from three space missions: Voyager (Uranus), Voyager (Neptune), and Magellan. Estimates derived from the model are tested against actual cost data for two independent missions, Viking and Mariner Jupiter/Saturn (MJS).

Remer, Donald S.; Sherif, Josef; Buchanan, Harry R.

1993-01-01

331

Space  

NSDL National Science Digital Library

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

Integrated Teaching And Learning Program

332

Voyager Interactive Web Interface to EarthScope  

NASA Astrophysics Data System (ADS)

Visualization of data is essential in helping scientists and students develop a conceptual understanding of relationships among many complex types of data and keep track of large amounts of information. Developed initially by UNAVCO for study of global-scale geodynamic processes, the Voyager map visualization tools have evolved into interactive, web-based map utilities that can make scientific results accessible to a large number and variety of educators and students as well as the originally targeted scientists. A portal to these map tools can be found at: http://jules.unavco.org. The Voyager tools provide on-line interactive data visualization through pre-determined map regions via a simple HTML/JavaScript interface (for large numbers of students using the tools simultaneously) or through student-selectable areas using a Java interface to a Generic Mapping Tools (GMT) engine. Students can access a variety of maps, satellite images, and geophysical data at a range of spatial scales for the earth and other planets of the solar system. Students can also choose from a variety of base maps (satellite mosaics, global topography, geoid, sea-floor age, strain rate and seismic hazard maps, and others) and can then add a number of geographic and geophysical overlays, for example coastlines, political boundaries, rivers and lakes, earthquake and volcano locations, stress axes, and observed and model plate motion, as well as deformation velocity vectors representing a compilation of over 5000 geodetic measurements from around the world. The related educational website, "Exploring our Dynamic Planet", (http://www.dpc.ucar.edu/VoyagerJr/jvvjrtool.html) incorporates background materials and curricular activities that encourage students to explore Earth processes. One of the present curricular modules is designed for high school students or introductory-level undergraduate non-science majors. The purpose of the module is for students to examine real data to investigate how plate tectonic processes are reflected in observed geophysical phenomena. Constructing maps by controlling map parameters and answering open-ended questions which describe, compare relationships, and work with both observed and model data, promote conceptual understanding of plate tectonics and related processes. The goals of curricular development emphasize inquiry, development of critical thinking skills, and student-centered interests. Custom editions of the map utility have been made as the "Jules Verne Voyager" and "Voyager Junior", for the International Lithosphere Project's "Global Strain Rate Map", and for EarthScope Education and Outreach as "EarthScope Voyager Jr.". For the latter, a number of EarthScope-specific features have been added, including locations of proposed USArray (seismic), Plate Boundary Observatory (geodetic), and San Andreas Fault Observatory at Depth sites, plus detailed maps and geographically referenced examples of EarthScope-related scientific investigations. As EarthScope develops, maps will be updated in `real time' so that students of all ages can use the data in formal and informal educational settings.

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

2004-12-01

333

Educating the next generation of SETI scientists: Voyages through time  

NASA Astrophysics Data System (ADS)

The search for extraterrestrial intelligence (SETI) could succeed tomorrow, or not for many generations, or never. SETI scientists are very cognizant of the need to train the next generation of researchers who can carry on this vast scientific exploration. Previously, the SETI Institute has met this challenge by developing supplementary teacher's guides for elementary and middle schools called "Life In the Universe" and published by Teacher Ideas Press. Currently, we are engaged in a far more challenging project that is funded primarily by the National Science Foundation (NSF). The SETI Institute is creating a year long, interdisciplinary, high school science curriculum called "Voyages Through Time: Everything Evolves". We are using the theme of evolution to weave a panoramic vista for students that begins with the origin of the universe, encompasses our own origin and evolution, and looks at the evolution of technology and our possible future. By integrating different scientific and technical disciplines to explore how we answer fundamentally important questions, we hope to excite and motivate high school students with the opportunities offered by the way science is practiced today. We invite them to plan a future in which they help to enrich the answers to the big questions: Where did I come from? Where am I going? is anybody else out there? Voyages Through Time consists of six modules on CD-ROMs for teachers and students that have been extensively tested both regionally and nationally. Publication is expected in 2003. The partners in the development of this curriculum are the SETI Institute, NASA Ames Research Center, California Academy of Sciences, and San Francisco State University. Voyages Through Time is funded by the NSF (IMD # 9730693) with additional support from NASA, Hewlett Packard Company, The Foundation for Microbiology, and the Federated Charitable Campaign. For further information, visit: http://www.seti.org/education/Welcome.html.

DeVore, Edna; Tarter, Jill; Fisher, Jane; O'Sullivan, Kathleen; Pendleton, Yvonne; Taylor, Sam; Burke, Margaret

2003-08-01

334

Educating the Next Generation of SETI Scientists: Voyages Through Time  

NASA Astrophysics Data System (ADS)

The search for extraterrestrial intelligence (SETI) could succeed tomorrow, or not for many generations, or never. SETI scientists are very cognizant of the need to train the next generation of researchers who can carry on this vast scientific exploration. Previously, the SETI Institute has met this challenge by developing supplementary teachers' guides for elementary and middle schools called "Life In The Universe" and published by Teacher Ideas Press. Currently, we are engaged in a far more challenging project that is funded primarily by the National Science Foundation (NSF). The SETI Institute is creating a year long, interdisciplinary, high school science curriculum called "Voyages Through Time: Everything Evolves". We are using the theme of evolution to weave a panoramic vista for students that begins with the origin of the universe, encompasses our own origin and evolution, and looks at the evolution of technology and our possible future. By integrating different scientific and technical disciplines to explore how we answer fundamentally important questions, we hope to excite and motivate high school students with the opportunities offered by the way science is practiced today. We invite them to plan a future in which they help to enrich the answers to the big questions: Where did I come from? Where am I going? Is anybody else out there? "Voyages Through Time" consists of six modules on CD-ROMs for teachers and students that have been extensively tested both regionally and nationally. Publication is expected in 2003. The partners in the development of this curriculum are the SETI Institute, NASA Ames Research Center, California Academy of Sciences, and San Francisco State University. "Voyages Through Time" is funded by the NSF (IMD # 9730693) with additional support from NASA, Hewlett Packard Company, The Foundation for Microbiology, and the FederatedCharitableCampaign.Forfurtherinformation,visit: http://www.seti.org/education/Welcome.html.

Devore, Edna

2002-01-01

335

Microwave communications from outer planets - The Voyager Project  

NASA Technical Reports Server (NTRS)

The paper summarizes the Voyager Project, the mission objectives, and the spacecraft communications system required to meet the mission objectives. The primary emphasis of the mission is on comparative studies of the Jupiter and Saturn systems in the areas of: (1) the environment, atmosphere and body characteristics of the planets, and one or more of the satellites, (2) the nature of the recently discovered Jovian ring and the rings of Saturn, and (3) the interplanetary medium at increasing distances from the sun. The complexities and problems, such as power consumption, weight, and antenna pointing constraints are presented, along with a detailed description of the radio frequency and S/X-band antenna subsystems.

Brejcha, A. G.

1980-01-01

336

Uranus satellites - Hapke parameters from Voyager disk-integrated photometry  

NASA Technical Reports Server (NTRS)

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

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

1988-01-01

337

Mission design challenges posed by the Voyager 2 Neptune encounter  

NASA Technical Reports Server (NTRS)

A major challenge for the Voyager 2 Neptune encounter lies in the detailed design of a trajectory that achieves science objectives at the planet as well as at its large satellite, Triton. This achievement demands a close flyby of the primary, whereas the planet's great distance makes such an undertaking especially challenging. Changing estimates and uncertainties of parameters characterizing the Neptune environment, particularly ring, atmosphere and radiation models, affect the mission design. These effects are investigated and trade-offs among candidate trajectories are examined with respect to spacecraft performance, avoidance of risk and science objective achievement.

Cesarone, R. J.; Potts, C. L.; Francis, K.; Kosmann, W. J.; Matousek, S. E.

1988-01-01

338

The Jupiter system through the eyes of Voyager 1  

USGS Publications Warehouse

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

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

1979-01-01

339

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

340

Uranus satellites - Hapke parameters from Voyager disk-integrated photometry  

NASA Astrophysics Data System (ADS)

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

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

1988-05-01

341

Preliminary science results of Voyager 1 Saturn encounter  

NASA Technical Reports Server (NTRS)

Preliminary science results of the Voyager 1 encounter of the planet Saturn are reported. On August 22, 1980, the spacecraft was 109 million km (68 million mi) from Saturn. Closest approach to Saturn took place on November 12, at 3:46 p.m. (PDT), when the spacecraft passed 126,000 km (78,000 mi) from the cloud tops. Measurements of the atmosphere, wind speed, radiation, six surrounding rings, and the planet's old and newly found satellites were recorded. The encounter ended December 15, 1980. The spacecraft took more than 17,500 photographs of Saturn and its satellites.

Bane, D.

1981-01-01

342

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

343

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

Code of Federal Regulations, 2013 CFR

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

2013-10-01

344

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

345

Monitor and Control of the Deep-Space network via Secure Web  

NASA Technical Reports Server (NTRS)

(view graph) NASA lead center for robotic space exploration. Operating division of Caltech/Jet Propulsion Laboratory. Current missions, Voyagers, Galileo, Pathfinder, Global Surveyor. Upcoming missions, Cassini, Mars and New Millennium.

Lamarra, N.

1997-01-01

346

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

NASA Astrophysics Data System (ADS)

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

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

2009-06-01

347

Analysis of the Voyager images of Jovian lighting  

SciTech Connect

In 1979, Voyager I provided the first strong evidence for the existence of lightning on another planet. Two pictures taken while the spacecraft was in Jupiter's shadow reveal about three dozen luminous spots on the night side of the planet. After careful examination of these spots, it was concluded that they are lightning flashes occurring somewhere in Jupiter's atmosphere. A search through the additional Voyage I and II images of Jupiter's night hemisphere failed to locate any additional lightning flashes. The lower limit for the planetary lightning rate on Jupiter is found to be 10/sup -4/ km/sup -2/ yr/sup -1/. It must be noted that the spacecraft could only detect lightning discharges at least 1000 times higher than typical terrestrial flashes. Furthermore, due to attenuation, any discharges occurring deep within the atmosphere could not have been imaged. Calculations suggest that the actual flash rate could be about 0.1 km/sup -2/ yr/sup -1/. Analysis of the lightning images reveals that the flashes group near 50/sup 0/ N latitude. High-resolution photographs of the lightning region made in daylight about 65 hours before the discovery images show long, light ribbon-like clouds. Almost every flash appears to be associated with one of these clouds.

Williams, M.A.

1986-01-01

348

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

349

Plasma wave observations near jupiter: initial results from voyager 2.  

PubMed

This report provides an initial survey of results from the plasma wave instrument on the Voyager 2 spacecraft, which flew by Jupiter on 9 July 1979. Measurements made during the approach to the planet show that low-frequency radio emissions from Jupiter have a strong latitudinal dependence, with a sharply defined shadow zone near the equatorial plane. At the magnetopause a new type of broadband electric field turbulence was detected, and strong electrostatic emissions near the upper hybrid resonance frequency were discovered near the low-frequency cutoff of the continuum radiation. Strong whistler-mode turbulence was again detected in the inner magnetosphere, although in this case extending out to substantially larger radial distances than for Voyager 1. In the predawn tail region, continuum radiation was observed extending down to extremely low frequencies, approximately 30 hertz, an indication that the spacecraft was entering a region of very low density, approximately 1.0 x 10(-5) per cubic centimeter, possibly similar to the lobes of Earth's magnetotail. PMID:17733920

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

1979-11-23

350

Encounter with Saturn: Voyager 1 imaging science results  

USGS Publications Warehouse

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

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

1981-01-01

351

Shared Voyage: Learning and Unlearning from Remarkable Projects  

NASA Technical Reports Server (NTRS)

Shared Voyage is about four remarkable projects: the Advanced Composition Explorer (NASA), the Joint Air-to-Surface Standoff Missile (U.S. Air Force), the Pathfinder Solar-Powered Airplane (NASA), and the Advanced Medium Range Air-to-Air Missile (U.S.Air Force). Each project is presented as a case study comprised of stories collected from key members of the project teams. The stories found in the book are included with the purpose of providing an effective learning source for project management, encouraging the unlearning of outdated project management concepts, and enhancing awareness of the contexts surrounding different projects. Significantly different from project concepts found in most project management literature, Shared Voyage highlights concepts like a will to win, a results-oriented focus, and collaboration through trust. All four project teams researched in this study applied similar concepts; however, they applied them differently, tailoring them to fit the context of their own particular projects. It is clear that the one best way approach which is still the prevailing paradigm in project management literature should be replaced by a new paradigm: Even though general project management principles exist, their successful application depends on the specifics of the situation.

Laufer, Alexander; Post, Todd; Hoffman, Edward J.

2005-01-01

352

Probing the domain structure of BiFeO3 epitaxial films with three-dimensional reciprocal space mapping  

NASA Astrophysics Data System (ADS)

High-resolution 3-Dimensional Reciprocal Space Mapping (3D-RSM) has been performed on mixed-phase BiFeO3 (BFO) epitaxial films on (001)-oriented LaAlO3 substrates. Our results demonstrate that 3D-RSM is an effective way to present a structural overview of the different BFO polymorphs, domain variants, and even the interfacial regions between coexisting triclinic phases. The dislocation-free boundaries between the triclinic phases revealed by these 3D-RSMs are believed to be responsible for the large electromechanical response found in mixed-phase BFO films. This study demonstrates the unique merits of the 3D-RSM technique for the structural characterization of ferroic films with complicated domain structures.

Luo, Z. L.; Huang, H.; Zhou, H.; Chen, Z. H.; Yang, Y.; Wu, L.; Zhu, C.; Wang, H.; Yang, M.; Hu, S.; Wen, H.; Zhang, X.; Zhang, Z.; Chen, L.; Fong, D. D.; Gao, C.

2014-05-01

353

Space.  

ERIC Educational Resources Information Center

This annotated subject guide to Web sites and additional resources focuses on space and astronomy. Specifies age levels for resources that include Web sites, CD-ROMS and software, videos, books, audios, and magazines; offers professional resources; and presents a relevant class activity. (LRW)

Web Feet K-8, 2001

2001-01-01

354

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

355

Successes and failures of shallow-water interpretations of Voyager wind data.  

PubMed

Studying the dynamics of Jupiter's atmosphere is a rewarding experience, in part because the planet's cloud-top circulations are easy to track from space, the jet streams flow in straight lines eastward or westward, and there is enough room for the vortices to usually keep out of each other's way. Earth, in contrast, is a planet with global circulations that are not easy to track from space, with jet streams that make wide, fluctuating arcs as they negotiate mountain ranges, and with vortices that are constantly jostling against each other in a cramped environment. But we know a great deal more about the vertical structure of Earth's atmosphere than of Jupiter's. In order to make headway on the Jovian problem, researchers have turned to the shallow-water model as a guide to interpreting the Voyager wind data. The shallow-water model matches the character of the data because it combines high-resolution horizontal dynamics with low-resolution vertical structure, but there is no guarantee that it captures the character of Jupiter's atmosphere itself. Remarkably, the model does well at reproducing the Great Red Spot, and it has revealed that Jupiter is clever about how it manages its vorticity by arranging its zonal winds to be neutrally stable with respect to Arnol'd's second stability theorem. We discuss reasons why the shallow-water model works for Jupiter and point out the limitations that are motivating researchers to develop more realistic models. PMID:12780101

Dowling, Timothy E.

1994-06-01

356

Outer Planets/Solar Probe Project: Solar Probe  

NASA Technical Reports Server (NTRS)

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

Tsurutani, B. T.

2000-01-01

357

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

358

Radioisotope Power: A Key Technology for Deep Space Explorations  

NASA Technical Reports Server (NTRS)

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

Schmidt, George R.; Sutliff, Thomas J.; Duddzinski, Leonard

2009-01-01

359

Radioisotope Power: A Key Technology for Deep Space Exploration  

NASA Technical Reports Server (NTRS)

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

Schmidt, George; Sutliff, Tom; Dudzinski, Leonard

2008-01-01

360

Orbit determination for the Voyager II Uranus encounter  

NASA Technical Reports Server (NTRS)

The Voyager II flyby of Uranus in January 1986 was the most distant planetary encounter ever attempted, and presented unique challenges to the process of orbit determination. Long light-times and spacecraft receiver difficulties hampered the collection of two-way radiometric data and helped bring about the maturation of a Very Long Baseline Interferometry navigational data type during the long cruise from Saturn. Planet and satellite ephemeris uncertainties necessitated the use of the onboard spacecraft optical system for Uranus-relative navigation. During the close approach phase, these optical data were combined with radiometric data to drive the Uranus system-relative uncertainties down to the level of a few tens of kilometers. This paper contains qualitative and quantitative results and conclusions based on orbit determination experience during Uranus cruise and encounter. Topics include an overview of the navigation-related mission events and requirements, and a review of the salient orbit determination results.

Taylor, T. H.; Jacobson, R. A.; Synnott, S. P.; Lewis, G. D.; Riedel, J. E.

1986-01-01

361

Lower atmospheric composition of Jupiter from Voyager infrared measurements  

NASA Technical Reports Server (NTRS)

The observed spectrum of Jovian atmosphere exhibits spectral features of H2, CH4, C2H6, NH3, H2O, GeH4 and CH3D. Analytical programs were developed for radiative transfer calculations and for retrieval of lower atmospheric composition of Jupiter from the observed infrared spectrum. The program models developed are based line by line transmittance calculations with appropriate convolution of the instrument function. The constituent inversion programs were evaluated for accuracy by analyzing synthetic data for retrievals of NH3 profiles. The inversion programs were employed for retrieval of NH3 profiles from the Voyager infared data with results generally in agreement with the accepted values.

Abbas, M. M.

1984-01-01

362

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

363

Inuit and Englishman: The Nunavut Voyages of Martin Frobisher  

NSDL National Science Digital Library

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

364

The helium abundance of Saturn from Voyager measurements  

NASA Technical Reports Server (NTRS)

The helium abundance in the atmosphere of Saturn is obtained from Voyager measurements by two methods. The first method combines infrared spectra and vertical profiles derived from radio occultation measurements and yields a hydrogen mole fraction of q = 0.963 + or - 0.024 corresponding to a helium mass fraction of Y = 0.06 + or - 0.05. The estimated errors are primarily due to uncertainties in the radio occultation profile and in the abundance of methane, which contributes significantly to the mean molecular weight. The second method is based on the direct inversion of infrared spectra and yields values consistent with those from the first method; however, examination of the sensitivities of the two methods indicates that in the Saturnian case the first approach provides more accurate results. Comparison of the helium abundance of Saturn with that of Jupiter and the sun suggests that helium precipitation is significant in Saturn but may not have begun in Jupiter.

Conrath, B. J.; Hanel, R. A.; Gautier, D.; Hornstein, J. S.

1984-01-01

365

Energetic charged particles in Saturn's magnetosphere: Voyager 2 results  

SciTech Connect

Results from the cosmic-ray system on Voyager 2 in Saturn's magnetosphere are presented. During the inbound pass through the outer magnetosphere, the greater than or equal to 0.43-million-electron-volt proton flux was more intense, and both the proton and electron fluxes were more varible, than previously observed. These changes are attributed to the influence on the magnetosphere of variations in the solar wind conditions. Outbound, beyond 18 Saturn radii, impulsive bursts of 0.14- to > 1.0-million-electron-volt electrons were observed. In the inner magnetosphere, the charged particle absorption signatures of Mimas, Enceladus, and Tethys are used to constrain the possible tilt and offset of Saturn's internal magnetic dipole. At approx. 3 Saturn radii, a transient decrease was observed in the electron flux which was not due to Mimas. Characteristics of this decrease suggest the existence of additional material, perhaps another satellite, in the orbit of Mimas.

Vogt, R.E. (California Inst. of Tech., Pasadena, CA); Chenette, D.L.; Cummings, A.C.; Garrard, T.L.; Stone, E.C.; Schardt, A.W.; Trainor, J.H.; Lal, N.; McDonald, F.B.

1982-01-29

366

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

367

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

368

The voyager 2 encounter with the neptunian system.  

PubMed

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 new 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. PMID:17755996

Stone, E C; Miner, E D

1989-12-15

369

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

370

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

371

Stellar observations with the Voyager EUV objective grating spectrograph  

NASA Technical Reports Server (NTRS)

During the periods of interplanetary cruise the Voyager ultraviolet spectrometers are used to provide unique and otherwise unobtainable observations in the extreme ultraviolet (EUV, 500 to 1200) and the far ultraviolet (FUV, 912 to 1220 A). These observations include the spectra of hot stellar sources as well as emission from the interplanetary medium. Recent results of note include: (1)Extensive spectrophotometric coverage of a superoutburst of the dwarf nova VW Hydri, which showed a clear 1/2 day delay in the outburst at 1000 A relative to that observed in the optical and a curious dip in the FUV light curve near maximum light. The Voyager observations were part of a comprehensive and highly successful campaign involving EXOSAT, IUE and ground based observations of this dwarf nova; (2)A comprehensive study of Be star spectra and variability. These results show the critical importance of FUV observations in the study of the effects of stellar rotation in hot stars; (3)The detection of a strong O VI absorption feature in the spectrum of the PG 1159-like object H1504+65. This detection along with the optical identification of weak O IV lines was a key to the interpretation of this object; which is of extremely high (>150,000K) temperature and appears to be a unique example of a stellar atmosphere devoid of H and He; (4)An analysis of an extremely long duration spectrum of the EUV and FUV sky background, which establishes important new upper limits on both continuum and line emission. This result also provide the first detection of interplanetary Lyman gamma.

Holberg, J. B.; Polidan, R. S.; Barry, D. C.

1986-01-01

372

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

373

The Jet Propulsion Laboratory space exploration - Past, present and future  

NASA Astrophysics Data System (ADS)

Attention is given to the most recent scientific results from space exploration carried out by JPL. A brief background of JPL's history is presented, and the Deep Space Network, JPL's system of antennas which communicates with spacecraft, is described. Results from the missions of Voyager 1 and Voyager 2 are discussed. Consideration is given to the atmosphere, rings, satellites, and magnetospheres of Jupiter, Saturn, Uranus, and Neptune. The impact of spray research on space exploration is briefly discussed. An overview of future missions and new NASA policies is also presented.

Bellan, Josette

1993-04-01

374

75 FR 70595 - Limited Service Domestic Voyage Load Lines for River Barges on Lake Michigan  

Federal Register 2010, 2011, 2012, 2013

...Domestic Voyage Load Lines for River Barges on Lake Michigan AGENCY: Coast Guard, DHS. ACTION...river barges to be exempted from the normal Great Lakes load line assignment while operating on Lake Michigan. Depending on the route,...

2010-11-18

375

Jupiters Magnetopause, Bow Shock, and 10-Hour Modulated Magnetosheath: Voyagers 1 and 2.  

National Technical Information Service (NTIS)

Fine scale magnetic field data from the Voyager 1 and 2 magnetopause and bow shock crossings at Jupiter were analyzed. Explicit models of the dawnside magnetopause and bow shock in Jupiter's orbital plane employ an axisymmetric parabola and hyperbola, res...

R. P. Lepping L. F. Burlaga L. W. Klein

1980-01-01

376

Changes on Io around Maui and Amirani between Voyager 1 and Galileo's second orbit  

NASA Technical Reports Server (NTRS)

Detail of changes on Jupiter's moon Io in the region around Maui and Amirani as seen by the Voyager 1 spacecraft in April 1979 (left frame) and NASA's Galileo spacecraft in September 1996 (right frame). North is to the top of both frames. The dark, north - south running linear feature, Amirani, is approximately 350 km long. Maui is the large circular feature immediately west of the southern end of Amirani. Note the brightening of the west side of Maui and the bright patch on the west side of Amirani.

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

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

1996-01-01

377

Changes on Io around Volund between Voyager 1 and Galileo's second orbit  

NASA Technical Reports Server (NTRS)

Detail of changes on Jupiter's moon Io in the region around Volund as seen by the Voyager 1 spacecraft in April 1979 (left frame) and NASA's Galileo spacecraft in September 1996 (right frame). North is to the top of both frames which are approximately 600 kilometers by 600 kilometers. Note the new linear feature, which may be a volcanic fissure, trending east from the southern end of Volund. Dark diffuse material lies to the west and a ring of bright material which may be SO2- rich plume deposits appears to be centered near the middle of the new linear feature.

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

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

1996-01-01

378

Satellites of Uranus - Disk-integrated photometry from Voyager imaging observations  

Microsoft Academic Search

Voyager 2 imaging observations over a wide range of phase angles are used to determine the fundamental photometric parameters for the five largest satellites of Uranus. Over the spectral range covered by Voyager cameras (approximately 350-600 nm) the disk-averaged colors are moderately gray (no redder than the spectrum of Saturn's satellite Phoebe). Geometric albedos range from 0.19 for Umbriel to

J. Veverka; P. Thomas; P. Helfenstein; R. H. Brown; T. V. Johnson

1987-01-01

379

Voyager 0.2-lbf thruster valve assembly short pulse test report  

NASA Technical Reports Server (NTRS)

The short pulse width testing completed on the Voyager 0.2-lbf thruster value assemblies (T/VA's) and the disassembly and inspection of T/VA S/N 020 is reported. The purpose for performing the short pulse width testing on Voyager 0.2-lbf thruster valve assemblies (T/VA's) was to determine: (1) impulse bit versus electrical pulse width; (2) impulse bit variations versus electrical pulse width; and (3) whether the short pulses decrease thruster life.

Johnson, D. R.

1985-01-01

380

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

NASA Technical Reports Server (NTRS)

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

Bishop, James

1991-01-01

381

Interplanetary Shocks and Solar Wind Structure Approaching Solar Maximum: Helios, IMP8 and Voyager Observations  

Microsoft Academic Search

We studied solar wind observations of five different spacecraft: Helios 1, Helios 2, IMP-8, Voyager 1 and Voyager 2, from November 1977 to February 1978. In this period the large-scale dynamics of the solar wind near of the ecliptic plane\\u000a was characterized by transient forward shocks (TFSs), ejecta, unstable corotating interaction regions (CIRs), and complex\\u000a and variable magnetic sector structures.

A. González-Esparza

2001-01-01

382

New coding advances for deep space communications  

NASA Technical Reports Server (NTRS)

Advances made in error-correction coding for deep space communications are described. The code believed to be the best is a (15, 1/6) convolutional code, with maximum likelihood decoding; when it is concatenated with a 10-bit Reed-Solomon code, it achieves a bit error rate of 10 to the -6th, at a bit SNR of 0.42 dB. This code outperforms the Voyager code by 2.11 dB. The use of source statics in decoding convolutionally encoded Voyager images from the Uranus encounter is investigated, and it is found that a 2 dB decoding gain can be achieved.

Yuen, Joseph H.

1987-01-01

383

Laser Raman probe diagnostics  

NASA Astrophysics Data System (ADS)

The overall objective of this work is to provide a scientific basis for a new non-perturbing, space and time resolved optical probe of gas temperature and constituency in combustion systems. The major part of the effort is focussed on the development of Raman scattering methods to accomplish this goal. Effort is also directed toward the goal of using other compatible measurement techniques (viz., laser velocimetry) in an integrated probe system for flame characterization.

Lapp, M.; Penney, C. M.; Warshaw, S.

1982-11-01

384

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

385

Molecular Probes  

NSDL National Science Digital Library

Supported commercially by Molecular Probes, this site provides an overview of molecular probe technology as well as a searchable bibliography, a list of related literature, and an outstanding photo gallery with examples of probe applications. The Gallery contains 22 different categories, from Actin and Tubulin Probes to Yeast and Other Fungi Stains, with several images provided for each category. A help link provides tips on using some of the probes and stains, a list of FAQs, and a list of more general technical questions related to probe technology.

1998-01-01

386

EMISSION-LINE GALAXIES FROM THE HUBBLE SPACE TELESCOPE PROBING EVOLUTION AND REIONIZATION SPECTROSCOPICALLY (PEARS) GRISM SURVEY. II. THE COMPLETE SAMPLE  

SciTech Connect

We present a full analysis of the Probing Evolution And Reionization Spectroscopically (PEARS) slitess grism spectroscopic data obtained with the Advanced Camera for Surveys on board Hubble Space Telescope. PEARS covers fields within both the Great Observatories Origins Deep Survey (GOODS) North and South fields, making it ideal as a random survey of galaxies, as well as the availability of a wide variety of ancillary observations complemented by the spectroscopic results. Using the PEARS data, we are able to identify star-forming galaxies (SFGs) within the redshift volume 0 < z < 1.5. Star-forming regions in the PEARS survey are pinpointed independently of the host galaxy. This method allows us to detect the presence of multiple emission-line regions (ELRs) within a single galaxy. We identified a total of 1162 H{alpha}, [O III], and/or [O II] emission lines in the PEARS sample of 906 galaxies to a limiting flux of {approx}10{sup -18} erg s{sup -1} cm{sup -2}. The ELRs have also been compared to the properties of the host galaxy, including morphology, luminosity, and mass. From this analysis, we find three key results: (1) the computed line luminosities show evidence of a flattening in the luminosity function with increasing redshift; (2) the star-forming systems show evidence of complex morphologies with star formation occurring predominantly within one effective (half-light) radius. However, the morphologies show no correlation with host stellar mass. (3) Also, the number density of SFGs with M{sub *} {>=} 10{sup 9} M{sub Sun} decreases by an order of magnitude at z {<=} 0.5 relative to the number at 0.5 < z < 0.9, supporting the argument of galaxy downsizing.

Pirzkal, Nor; Rothberg, Barry; Ly, Chun; Grogin, Norman A.; Dahlen, Tomas; Noeske, Kai G.; Bellini, Andrea [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21210 (United States); Malhotra, Sangeeta; Rhoads, James E.; Cohen, Seth H.; Mechtley, Matthew; Windhorst, Rogier A. [School of Earth And Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States); Meurer, Gerhardt R. [International Centre for Radio Astronomy Research, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia); Walsh, Jeremy R. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany); Hathi, Nimish P. [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Holwerda, Benne W. [ESA-ESTEC, Keplerlaan 1, 2200 AG, Noordwijk (Netherlands); Straughn, Amber N. [Astrophysics Science Division, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States)

2013-07-20

387

Emission-line Galaxies from the Hubble Space Telescope Probing Evolution and Reionization Spectroscopically (PEARS) Grism Survey. II. The Complete Sample  

NASA Astrophysics Data System (ADS)

We present a full analysis of the Probing Evolution And Reionization Spectroscopically (PEARS) slitess grism spectroscopic data obtained with the Advanced Camera for Surveys on board Hubble Space Telescope. PEARS covers fields within both the Great Observatories Origins Deep Survey (GOODS) North and South fields, making it ideal as a random survey of galaxies, as well as the availability of a wide variety of ancillary observations complemented by the spectroscopic results. Using the PEARS data, we are able to identify star-forming galaxies (SFGs) within the redshift volume 0 < z < 1.5. Star-forming regions in the PEARS survey are pinpointed independently of the host galaxy. This method allows us to detect the presence of multiple emission-line regions (ELRs) within a single galaxy. We identified a total of 1162 H?, [O III], and/or [O II] emission lines in the PEARS sample of 906 galaxies to a limiting flux of ~10-18 erg s-1 cm-2. The ELRs have also been compared to the properties of the host galaxy, including morphology, luminosity, and mass. From this analysis, we find three key results: (1) the computed line luminosities show evidence of a flattening in the luminosity function with increasing redshift; (2) the star-forming systems show evidence of complex morphologies with star formation occurring predominantly within one effective (half-light) radius. However, the morphologies show no correlation with host stellar mass. (3) Also, the number density of SFGs with M * >= 109 M ? decreases by an order of magnitude at z <= 0.5 relative to the number at 0.5 < z < 0.9, supporting the argument of galaxy downsizing.

Pirzkal, Nor; Rothberg, Barry; Ly, Chun; Malhotra, Sangeeta; Rhoads, James E.; Grogin, Norman A.; Dahlen, Tomas; Noeske, Kai G.; Meurer, Gerhardt R.; Walsh, Jeremy R.; Hathi, Nimish P.; Cohen, Seth H.; Bellini, Andrea; Holwerda, Benne W.; Straughn, Amber N.; Mechtley, Matthew; Windhorst, Rogier A.

2013-07-01

388

Radiation environment in the Heliosphere from galactic cosmic rays and radiation hazard for space-probes in dependence of their trajectories: integral multiplicity and coupling function for radiation dose, monitoring and forecasting  

NASA Astrophysics Data System (ADS)

On the basis of cosmic ray CR and solar activity SA data in the past for more than four solar cycles taking into account the theory of convection-diffusion and drift global modulation of galactic CR in the Heliosphere we determine the parameters of convection-diffusion and drift mechanisms of CR long term variation in dependence of particles energy By using these results and published regularly elsewhere predictions of expected SA variation we may made prediction of expected in near future long-term variation of radiation environment in the Heliosphere owed by galactic CR From other hand we introduce new nominations integral multiplicity and coupling function for radiation dose inside space-probe caused by galactic CR in dependence of shielding for different places in space-probe By the method of coupling functions we estimate the connection between CR intensity long-term variation and radiation hazard for space-probes in dependence of their trajectories distance from the Sun and helio-latitude We show that by this way we may make monitoring and forecasting for several years ahead of expected differential per unit of time and integral radiation doze per some interval of time for future astronauts e g on missions to Moon and Mars and electronic systems due by galactic CR in the Heliosphere

Dorman, Lev I.

389

Current Sheets in the Heliosheath: Voyager 1, 2009  

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

390

Plasma observations near uranus: initial results from voyager 2.  

PubMed

Extensive measurements of low-energy positive ions and electrons in the vicinity of Uranus have revealed a fully developed magnetosphere. The magnetospheric plasma has a warm component with a temperature of 4 to 50 electron volts and a peak density of roughly 2 protons per cubic centimeter, and a hot component, with a temperature of a few kiloelectron volts and a peak density of roughly 0.1 proton per cubic centimeter. The warm component is observed both inside and outside of L = 5, whereas the hot component is excluded from the region inside of that L shell. Possible sources of the plasma in the magnetosphere are the extended hydrogen corona, the solar wind, and the ionosphere. The Uranian moons do not appear to be a significant plasma source. The boundary of the hot plasma component at L = 5 may be associated either with Miranda or with the inner limit of a deeply penetrating, solar wind-driven magnetospheric convection system. The Voyager 2 spacecraft repeatedly encountered the plasma sheet in the magnetotail at locations that are consistent with a geometric model for the plasma sheet similar to that at Earth. PMID:17812895

Bridge, H S; Belcher, J W; Coppi, B; Lazarus, A J; McNutt, R L; Olbert, S; Richardson, J D; Sands, M R; Selesnick, R S; Sullivan, J D; Hartle, R E; Ogilvie, K W; Sittler, E C; Bagenal, F; Wolff, R S; Vasyliunas, V M; Siscoe, G L; Goertz, C K; Eviatar, A

1986-07-01

391

Magnetic field experiment for Voyagers 1 and 2  

NASA Technical Reports Server (NTRS)

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

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

1977-01-01

392

Voyager Observations of the Color of Saturn's Ring  

NASA Technical Reports Server (NTRS)

Previously unreduced high resolution Voyager 2 images of Saturn's main rings are used to generate reflectivity (I/F) profiles as a function of radius. Ratios of profiles taken from green, violet, orange, and UV filter images are then produced. The I/F ratios are diagnostic of composition, and provide us with information on the rings' present state of compositional evolution. The rings are extremely reddish in color which suggests that they could not be pure water ice. The most likely candidates for the non-icy components are silicates and organics. The sources of these pollutants are of extreme importance in determining the compositional history of the rings. The radial profiles of ring color ratio exhibit several very interesting properties: (a) broad-scale, fairly smooth, color variations which are only weakly correlated with underlying ring structure (optical depth variations) across the outer C ring and inner B ring as well as the Cassini division region. These variations are probably consistent with ballistic transport; (b) fine-scale, noise-Like (but unquestionably real) color variations across at least the outer two-thirds of the B ring. Not only the "redness" but the spectral shape varies. These variations are currently unexplained. Groundbased spectroscopic observations should be pursued to study the implied compositional heterogeneities on at least the larger scales. This data set will be used for modeling of the color and composition of the main rings using ballistic transport and radiative transfer theories.

Estrada, Paul R.; Cuzzi, Jeffrey N.; Morrison, David (Technical Monitor)

1994-01-01

393

Voyager photometry of surface features on Ganymede and Callisto  

NASA Technical Reports Server (NTRS)

Photometric properties of selected surface features on Ganymede and Callisto are studied, using Voyager images over phase angles from 10 to 124 deg, taken with a clear filter (effective wavelength of approximately 0.5 microns). Normal reflectances on Ganymede average 0.35 for the cratered terrain, and 0.44 for the grooved terrain; the ubiquitous cratered terrain on Callisto is 0.18. The photometric properties of these regions are described by a simple scattering function, where the function of the phase angle is qualitatively similar to that of the moon, i.e., concave upward. By contrast, bright craters on both satellites have functions of the phase angle which are concave downward. The scattering function is not Lambertian, and may be due to an admixture of a small amount of dark, opaque silicate grains with the frost deposits. The brightest craters on Callisto have reflectances which are 10% lower than the brightest craters on Ganymede, and both have similar scattering laws.

Squyres, S. W.; Veverka, J.

1981-01-01

394

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.

395

Space Missions  

NSDL National Science Digital Library

With three levels to choose from on each page - beginner, intermediate or advanced - this site provides in formation on past and current exploration ideas and achievements. The advances science has made in the space exploration area, such as having a permanent space station in space and the hundreds of probes, satellite, and space shuttles that have been launched. Advanced telescopes have given scientists the opportunity to see far beyond we ever imagined, and new explorations are found every day. Also featured are details about the International space station and what kinds of experiments scientists do in outer space.

Russell, Randy

2004-05-10

396

Stormtime Relativistic Electron Phase Space Density Profiles Measured by the Van Allen Probes Using L* Computed From the Rice Convection Model-Equilibrium  

NASA Astrophysics Data System (ADS)

Relativistic radiation belt electrons during geomagnetic storms are often analyzed using phase space density (PSD) radial profiles in coordinates derived from the three adiabatic invariants of particle motion in the magnetosphere. The radial coordinate in these profiles is L*, which is equivalent to the third adiabatic invariant defined as the magnetic flux enclosed by the drift of the particle around the Earth. L* is a global quantity and cannot be easily measured, so its values are highly model dependent. Previous work has used L* derived from empirical geomagnetic field models. These models represent an average field for a given set of solar wind and activity levels, and only rarely reproduce the measured field values during storms. Typically, the investigators compare the results from several such models to assess the possible level of error in their PSD results. The self-consistent ring current model Rice Convection Model-Equilibrium (RCM-E) has been shown previously to perform better at reproducing spacecraft magnetic field measurements during storms. We analyze a recent moderate storm event to assess the difference in the electron PSD analysis with the L* computed with the two methods. The first method uses L* computed from the empirical geomagnetic field models of Tsganenko-Sitnov and Olsen-Pfitzer. We compare those results with a similar analysis including L* calculated from the RCM-E simulation of the storm. The storm on June 1, 2013 had a main phase of 8-hour duration and a minimum Dst of -118 nT. The energetic electrons in the energy range from 30 keV to 4 MeV were measured by the Magnetic Electron and Ion Spectrometers onboard the Van Allen Probes. These measurements display the classic profile with a pronounced drop in flux during the main phase and a slow rise in flux during the recovery phase. The observations show that by June 5th, the flux had not yet recovered fully to the measured pre-storm levels, especially above 1 MeV. We discuss the implications of the PSD analysis on our ability to diagnose accurately the radiation belts for the effects of wave-particle interactions.

Roeder, J. L.; Lemon, C. L.; Chen, M.; Fennell, J. F.; Claudepierre, S. G.; Mulligan, T. L.; Blake, J. B.; Clemmons, J. H.; Spence, H.

2013-12-01

397

COMPRESSIBLE 'TURBULENCE' OBSERVED IN THE HELIOSHEATH BY VOYAGER 2  

SciTech Connect

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

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

2009-09-20

398

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

PubMed

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

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

2005-09-23

399

Radial evolution of the solar wind from IMP 8 to Voyager 2  

NASA Technical Reports Server (NTRS)

Voyager 2 and Interplanetary Monitoring Platform (IMP) 8 data from 1977 through 1994 are presented and compared. Radial velocity and temperature structures remain intact over the distance from 1 to 43 AU, but density structures do not. Temperature and velocity changes are correlated and nearly in phase at 1 AU, but in the outer heliosphere temperature changes lead velocity changes by tens of days. Solar cycle variations are detected by both spacecraft, with minima in flux density and dynamic pressure near solar maxima. Differences between Voyager 2 and IMP 8 observations near the solar minimum in 1986-1987 are attributed to latitudinal gradients in solar wind properties. Solar rotation variations are often present even at 40 AU. The Voyager 2 temperature profile is best fit with a R(exp -0.49 +/- 0.01) decrease, much less steep than an adiabatic profile.

Richardson, John D.; Paularena, Karolen I.; Lazarus, Alan J.; Belcher, John W.

1995-01-01

400

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

Microsoft Academic Search

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

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

1981-01-01

401

The Voyager Universal Literacy System: Results from a Study of Kindergarten Students in Inner-City Schools  

ERIC Educational Resources Information Center

The evaluation of the Voyager Universal Literacy System[R] was designed to provide a rigorous assessment of the effectiveness of the program with beginning readers. Using a quasi-experimental design, researchers conducted a systematic evaluation of changes in 398 kindergarten students' command of early reading skills in 4 Voyager and 4 comparison…

Frechtling, Joy A.; Zhang, Xiaodong; Silverstein, Gary

2006-01-01

402

Results of the space shuttle vehicle ascent air data system probe calibration test using a 0.07-scale external tank forebody model (68T) in the AEDC 16-foot transonic wind tunnel (IA-310), volume 2  

NASA Technical Reports Server (NTRS)

A recalibration of the Space Shuttle Vehicle Ascent Air Data System probe was conducted in the Arnold Engineering and Development Center (AEDC) transonic wind tunnel. The purpose was to improve on the accuracy of the previous calibration in order to reduce the existing uncertainties in the system. A probe tip attached to a 0.07-scale External Tank Forebody model was tested at angles of attack of -8 to +4 degrees and sideslip angles of -4 to +4 degrees. High precision instrumentation was used to acquire pressure data at discrete Mach numbers ranging from 0.6 to 1.55. Pressure coefficient uncertainties were estimated at less than 0.0020. Additional information is given in tabular form.

Collette, J. G. R.

1991-01-01

403

Results of the space shuttle vehicle ascent air data system probe calibration test using a 0.07-scale external tank forebody model (68T) in the AEDC 16-foot transonic wind tunnel (IA-310), volume 1  

NASA Technical Reports Server (NTRS)

A recalibration of the Space Shuttle Vehicle Ascent Air Data System probe was conducted in the Arnold Engineering Development Center (AEDC) transonic wind tunnel. The purpose was to improve on the accuracy of the previous calibration in order to reduce the existing uncertainties in the system. A probe tip attached to a 0.07-scale External Tank Forebody model was tested at angles of attack of -8 to +4 degrees and sideslip angles of -4 to +4 degrees. High precision instrumentation was used to acquire pressure data at discrete Mach numbers ranging from 0.6 to 1.55. Pressure coefficient uncertainties were estimated at less than 0.0020. Data is given in graphical and tabular form.

Collette, J. G. R.

1991-01-01

404

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

405

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

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

406

Thickness of the Heliosheath, Return of the Pick-up Ions, and Voyager 1's Crossing the Heliopause  

NASA Astrophysics Data System (ADS)

Using results of remote sensing by energetic neutral atoms from IBEX, SOHO/HSTOF, and Cassini/INCA, in situ measurements of ~40-4000 keV protons in the heliosheath (HS) from Low Energy Charged Particle on Voyager 1 and Voyager 2, and outputs from numerical modeling of the termination shock, we estimate L, the characteristic thickness of the HS in the "upwind" direction (±45° in ecliptic longitude of the Nose at ? = 255°). A simple steady-state, internally consistent model gives L = 21 ± 6 AU for Voyager 1, L = 28 ± 8 AU for Voyager 2, and L = 25 ± 8 AU assuming that the same L value is valid for both spacecraft. We recognize that this is a very coarse cut at a very dynamic region of the heliosphere; but if the lower value L = 21 AU applies, one could expect Voyager 1 to cross the heliopause as early as late 2010.

Hsieh, K. C.; Giacalone, J.; Czechowski, A.; Hilchenbach, M.; Grzedzielski, S.; Kota, J.

2010-08-01

407

Preservation Methods Utilized for Space Food  

NASA Technical Reports Server (NTRS)

Food for manned space flight has been provided by NASA-Johnson Space Center since 1962. The various mission scenarios and space craft designs dictated the type of food preservation methodologies required to meet mission objectives. The preservation techniques used in space flight include freeze-dehydration, thermostabilization, irradiation, freezing and moisture adjustment. Innovative packaging material and techniques enhanced the shelf-stability of the food items. Future space voyages may include extended duration exploration missions requiring new packaging materials and advanced preservation techniques to meet mission goals of up to 5-year shelf-life foods.

Vodovotz, Yael; Bourland, Charles

2000-01-01

408

Space engineering  

NASA Technical Reports Server (NTRS)

Human productivity was studied for extravehicular tasks performed in microgravity, particularly including in-space assembly of truss structures and other large objects. Human factors research probed the anthropometric constraints imposed on microgravity task performance and the associated workstation design requirements. Anthropometric experiments included reach envelope tests conducted using the 3-D Acoustic Positioning System (3DAPS), which permitted measuring the range of reach possible for persons using foot restraints in neutral buoyancy, both with and without space suits. Much neutral buoyancy research was conducted using the support of water to simulate the weightlessness environment of space. It became clear over time that the anticipated EVA requirement associated with the Space Station and with in-space construction of interplanetary probes would heavily burden astronauts, and remotely operated robots (teleoperators) were increasingly considered to absorb the workload. Experience in human EVA productivity led naturally to teleoperation research into the remote performance of tasks through human controlled robots.

Alexander, Harold L.

1991-01-01

409

Voyager Universal Literacy System[R]. What Works Clearinghouse Intervention Report  

ERIC Educational Resources Information Center

The "Voyager Universal Literacy System"[R] is a core reading program designed to help students learn to read at or above grade level by the end of the third grade. This program uses strategies such as individual reading instruction, higher-level comprehension activities, problem solving, and writing. Students are also exposed to computer-based…

What Works Clearinghouse, 2007

2007-01-01

410

Two bright spots on Saturn's globe as observed by Voyager 2  

Microsoft Academic Search

Two bright spots shown by Voyager 2 images on Saturn's north temperate belt are discussed in terms of a simple photometric model in which the brightness differences are caused by obscuring matter above the main cloud layer. In the ultraviolet light, in which scattering by small particles is very effective, the spots are invisible. In the violet light they seem

H. Jantunen

1983-01-01

411

The evolution of the Voyager mission sequence software and trends for future mission sequence software systems  

NASA Technical Reports Server (NTRS)

The historical background of the spacecraft sequence generation process as it is represented by the Voyager mission to the outer planets is discussed. Present plans for future sequencing methods are examined, including the emphasis on cutting costs and the contrast between the centralized and distributed systems for sequencing. The use of artificial intelligence in mission sequencing is addressed.

Brooks, Robert N., Jr.

1988-01-01

412

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

Microsoft Academic Search

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

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

1991-01-01

413

The Three Voyages of Edmond Halley in the Paramore: 1698-1701  

NASA Astrophysics Data System (ADS)

On Thursday, October 20, 1698, a three-masted ship, captained by Edmond Halley with orders “to improve the knowledge of the Longitude and variations of the Compasse,” which he was to observe “with all the accuracy you can,” set sail from Deptford, England, on the first leg of the first voyage ever commissioned for strictly scientific purposes. Halley is now best known as an astronomer and for the comet that bears his name. However, his interests ranged over so many specialties that he is better described now by the 17th century title of “natural philosopher.” Among his various areas of study, the study of the earth took a major place, as shown by his many papers on the trade winds, the tides, and especially the magnetic field. This last interest led him to propose to the Royal Society that he make a voyage around the world “to discover what may be learnt … [of] the variations of the Magneticall Needle.” This ambitious undertaking was later scaled down to cover only the Atlantic Ocean, Halley made two voyages from 1698 to 1700, at one point reaching 52°S in his 52-foot vessel. As a tailpiece he made a third voyage in the summer and fall of 1701 to study the tides and tidal currents of the English Channel.

Agnew, Duncan Carr

414

Micron-Sized Particle Impacts Detected near Uranus by the Voyager 2 Plasma Wave Instrument.  

National Technical Information Service (NTIS)

During the Voyager 2 flyby of Uranus, the plasma wave and radio astronomy instruments detected a region of impulsive noise near the equatorial plane just inside the orbit of Miranda, at a radial distance of 4.51 RU. This noise is believed to be caused by ...

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

1986-01-01

415

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

416

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

417

The Magnetic-Anomaly Model of the Jovian Magnetosphere: A Post-Voyager Assessment  

Microsoft Academic Search

We reexamine the three predictions that we previously put forth as tests for the magnetic-anomaly model (in which the anomalously weak magnetic field region in the northern hemisphere of Jupiter influences the outer Jovian magnetosphere by one or more plasma interaction processes), taking into account the Voyager and other recent observations. Concerning the prediction of a restricted longitude range of

V. M. Vasyliunas; A. J. Dessler

1981-01-01

418

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

Microsoft Academic Search

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

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

1982-01-01

419

The Low Energy Charged Particle (LECP) experiment on the Voyager spacecraft  

Microsoft Academic Search

The Low Energy Charged Particle (LECP) experiment on the Voyager spacecraft is designed to provide comprehensive measurements of energetic particles in the Jovian, Saturnian, Uranian and interplanetary environments. These measurements will be used in establishing the morphology of the magnetospheres of Saturn and Uranus, including bow shock, magnetosheath, magnetotail, trapped radiation, and satellite-energetic particle interactions. The experiment consists of two

S. M. Krimigis; T. P. Armstrong; W. I. Axford; C. O. Bostrom; C. Y. Fan; G. Gloeckler; L. J. Lanzerotti

1977-01-01

420

With Community Colleges' Help, Voyager Program Expands Learning Opportunities for Children.  

ERIC Educational Resources Information Center

Describes the Voyager Program, a national educational initiative supporting elementary schools and teachers by providing essential supplies and a research-based curriculum. Reviews the role of selected community colleges in providing support for summer and after-school programs. (JDI)

Bumphus, Walter

1998-01-01

421

Survey of Low Energy Plasma Electrons in Saturn's Magnetosphere: Voyagers 1 and 2.  

National Technical Information Service (NTIS)

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 distribu...

E. C. Sittler K. W. Ogilvie J. D. Scudder

1983-01-01

422

A JPL Report: AI Takes on Space Tasks  

Microsoft Academic Search

The growing use of artificial intelligence (AI) at the Jet Propulsion Laboratory in mission operations and other areas of the space program is discussed. Mission operations is furthest along, two systems having begun operation in parallel with existing methods in time for Voyager 2's Neptune encounter in August 1989. One is called Sharp (spacecraft health automated reasoning prototype) and the

Ware Myers

1990-01-01

423

Multispectral imaging probe  

DOEpatents

A multispectral imaging probe delivers a range of wavelengths of excitation light to a target and collects a range of expressed light wavelengths. The multispectral imaging probe is adapted for mobile use and use in confined spaces, and is sealed against the effects of hostile environments. The multispectral imaging probe comprises a housing that defines a sealed volume that is substantially sealed from the surrounding environment. A beam splitting device mounts within the sealed volume. Excitation light is directed to the beam splitting device, which directs the excitation light to a target. Expressed light from the target reaches the beam splitting device along a path coaxial with the path traveled by the excitation light from the beam splitting device to the target. The beam splitting device directs expressed light to a collection subsystem for delivery to a detector. 8 figs.

Sandison, D.R.; Platzbecker, M.R.; Descour, M.R.; Armour, D.L.; Craig, M.J.; Richards-Kortum, R.

1999-07-27

424

Charged Kaon interferometric probes of space-time evolution in Au+Au collisions at sqrt[S(NN)]=200 GeV.  

PubMed

Bose-Einstein correlations of charged kaons are used to probe Au+Au collisions at sqrt[S(NN)]=200 GeV 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 N(part)1/3 with a zero intercept. Imaging analysis shows a deviation from a Gaussian tail at r greater than or approximately equal to 10 fm, although the bulk emission at lower radius is well described by a Gaussian. The presence of a non-Gaussian tail in the kaon source reaffirms that the particle emission region in a heavy-ion collision is extended, and that similar measurements with pions are not solely due to the decay of long-lived resonances. PMID:19905563

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

2009-10-01

425

Study of photoemission and work function of large surface areas, phase 3, phase 4. [wavelength dependences of photoelectric space probe materials  

NASA Technical Reports Server (NTRS)

The photoemission of materials which might be used in probe measurements of the exo-atmospheric electric field is considered by evaluating the wavelength dependence of their photoelectric yield for eleven elements over the range 800 to 3200 A. Yield data for zinc, copper beryllium, platinum, cadmium, graphite, carbon, gold, silver, tantalum, and tungsten show that copper-beryllium is a preferred material. Silver has one of the highest photoemissions when exposed to solar radiation.

1973-01-01

426

Babylon to Voyager and Beyond: A History of Planetary Astronomy  

NASA Astrophysics Data System (ADS)

Preface; Introduction; 1. The ancients; 2. Copernicus and the new cosmology; 3. Kepler and Galileo - the fall of epicycles and the start of telescopic astronomy; 4. The mid and late seventeenth century; 5. Consolidation; 6. The solar system expands; 7. The inner solar system in the nineteenth century; 8. The outer solar system in the nineteenth century; 9. Quiet interlude - the twentieth century prior to the space age; 10. The space age - terrestrial planets; 11. The space age - the outer planets; Glossary; Bibliography; Units; Name index; Subject index.

Leverington, David

2003-05-01

427

Optical probe  

DOEpatents

A compact optical probe is disclosed particularly useful for analysis of emissions in industrial environments. The instant invention provides a geometry for optically-based measurements that allows all optical components (source, detector, rely optics, etc.) to be located in proximity to one another. The geometry of the probe disclosed herein provides a means for making optical measurements in environments where it is difficult and/or expensive to gain access to the vicinity of a flow stream to be measured. Significantly, the lens geometry of the optical probe allows the analysis location within a flow stream being monitored to be moved while maintaining optical alignment of all components even when the optical probe is focused on a plurality of different analysis points within the flow stream.

Hencken, Kenneth (Pleasanton, CA); Flower, William L. (Livermore, CA)

1999-01-01

428

Clouds, Bands And Discrete Features On Saturn: Comparisons Between Cassini And Voyager  

NASA Astrophysics Data System (ADS)

We examine new images returned from Cassini spacecraft's ISS camera to analyze tropospheric cloud morphology of Saturn. We compare our findings to Voyager 2 observations to search for changes in global cloud morphology. Images were acquired around the equinox and our datasets provide near-global coverage in multiple wavelength bands. We find that the clouds exhibit the highest contrasts in infrared continuum centered at 752 & 939 nm (CB2 & CB3 filters, respectively) and 727 & 890 nm methane bands (MT2 & MT3). We compare the present day location of Saturn's bands to those of the Voyager era. We reconfirm multiple features that were previously found in Voyager's visible and Cassini infrared images in the northern hemisphere. First, we examine the Ribbon wave found by the Voyager missions (Sromovsky et al. 1983; Godfrey and Moore, 1986) at multiple wavelength bands. Next, we examine the behavior of a dark vortex that exhibits many similarities to the vortex labeled by Sromovsky et al. as Brown Spot 1. Our data also shows a visible-light counterpart to the String of Pearls feature, which appeared as a series of planet encircling bright spots in 5-micron VIMS images (Momary et al. 2006), suggesting that they are cloud clearings. Our images confirm that there are indeed a string of dark cloud-free spots in the region, which enable us to study their dynamics and compare our results to the VIMS measurements by Choi et al (2009). We also compare the appearance of the north-polar hexagon at multiple wavelengths. Our data also provides good coverage in the southern hemisphere, and we compare our results to Voyager images in 1980-81 and images acquired during the early phase of Cassini mission. Supported by the Cassini Project and a Summer Undergraduate Research Fellowship from Caltech.

Muro, Gabriel; Sayanagi, K. M.; Ewald, S. P.; Ingersoll, A. P.

2010-10-01

429

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

430

Understanding heliospheric origins with Solar Probe Plus  

NASA Astrophysics Data System (ADS)

The magnetic field is fundamental to solar activity and shapes the interplanetary environment, as clearly shown by the full three dimensional monitoring of the heliosphere provided by the measurements of the Helios, Ulysses, SOHO, ACE, Wind, STEREO and Voyager spacecraft. Magnetic fields are also the source for coronal heating and the very existence of the solar wind; produced by the sun’s dynamo and emerging into the corona magnetic fields become a conduit for waves, act to store energy, and then propel plasma into the heliosphere in the form of Coronal Mass Ejections (CMEs). Transformation of magnetic energy is also the source solar energetic particle events. The way in which solar convective energy couples to magnetic fields to produce the multifaceted heliosphere is at the heart of the Solar Probe Plus exploration. This contribution highlights the exciting perspectives for discovery provided by the SPP investigation of the sub-Alfvénic corona.

Velli, M. M.

2010-12-01

431

Phoenix Conductivity Probe  

NASA Technical Reports Server (NTRS)

This image taken by the Surface Stereo Imager on Sol 49, or the 49th Martian day of the mission (July 14, 2008), shows thermal and electrical conductivity probe on NASA's Phoenix Mars Lander's Robotic Arm.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is led by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

2008-01-01

432

Space: The New Frontier.  

ERIC Educational Resources Information Center

This document is designed primarily to describe the U.S. Space Program, its history, its current state of development, and its goals for the future. Chapter headings include: Space and You; The Early History of Space Flight; The Solar System; Space Probes and Satellites; Scientific Satellites and Sounding Rockets; Application Satellites, Unmanned…

National Aeronautics and Space Administration, Washington, DC.

433

Time and Space: A Collaborative Voyage for Junior Astronomers at Londonderry Middle School  

ERIC Educational Resources Information Center

One of the benefits of working at the middle school level is the opportunity to work with colleagues in a variety of content areas; this not only makes work more interesting, but offers a multidisciplinary approach to learning that ultimately benefits the students. In the Londonderry (New Hampshire) School District, collaboration between classroom…

Chessin, Paula; Payeur, Jessica; Chessin, Deborah

2012-01-01

434

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

NSDL National Science Digital Library

This is a series of three webpages about how humans and computers communicate. Learners will explore the binary and hexidecimal systems and how engineers use them to translate spacecraft data into images.

435

An unmanned probe to Pluto  

NASA Technical Reports Server (NTRS)

Now that Voyager II has completed its grand tour of the solar system, all the planets in the solar system, with the exception of Pluto, have been studied. Even now, missions to return to Mercury, Venus, Mars Jupiter, and Saturn are currently flying or are planned. However, a mission to explore Pluto is not, at the present time, being considered seriously. The design problem presented to the students was very general, i.e., design an unmanned mission to Pluto with a launch window constraint of the years 2000 to 2010. All other characteristics of the mission, such as mission type (flyby, orbiter, lander, penetrator), scientific objectives and payload, and the propulsion system were to be determined by the design teams. The design studies exposed several general problems to be solved. Due to the extreme distance to Pluto (and a corresponding travel time in the range of 10 to 25 years), the spacecraft had to be lighter and more robust than current spacecraft designs. In addition, advanced propulsion concepts had to be considered. These included the new generation of launch vehicles and upper stages and nuclear electric propulsion. The probe design offered an abundance of synthesis and analysis problems. These included sizing trade studies, selection of subsystem components, analysis of spacecraft dynamics, stability and control, structural design and material selection, trajectory design, and selection of scientific equipment. Since the characteristics of the mission, excluding the launch window, were to be determined by the design teams, the solutions varied widely.

1990-01-01

436

A three dimensional probe positioner  

NASA Astrophysics Data System (ADS)

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.; Dorf, L.; Furno, I.; Lapenta, G.

2008-10-01

437

Langmuir probe differential measurement technique in inductively coupled RF plasmas  

Microsoft Academic Search

A differential measurement technique has been proposed in order to reduce noise level and stray capacitance leakage usually affecting Langmuir probe data. The technique employs two identically designed and biased Langmuir probes, connected to an instrumentation amplifier. Both probes are immersed in plasma of approximately the same space potential, one of them being plasma current collecting probe, and the second

I. Djermanov; N. Djermanova; Zh Kiss'ovski; Ts Tsankov

2007-01-01

438

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

439

NMR Fingerprints of the Drug-like Natural-Product Space Identify Iotrochotazine?A: A Chemical Probe to Study Parkinson's Disease.  

PubMed

The NMR spectrum of a mixture of small molecules is a fingerprint of all of its components. Herein, we present an NMR fingerprint method that takes advantage of the fact that fractions contain simplified NMR profiles, with minimal signal overlap, to allow the identification of unique spectral patterns. The approach is exemplified in the identification of a novel natural product, iotrochotazine?A (1), sourced from an Australian marine sponge Iotrochota?sp. Compound 1 was used as a chemical probe in a phenotypic assay panel based on human olfactory neurosphere-derived cells (hONS) from idiopathic Parkinson's disease patients. Compound 1 at 1??M was not cytotoxic but specifically affected the morphology and cellular distribution of lysosomes and early endosomes. PMID:24737726

Grkovic, Tanja; Pouwer, Rebecca H; Vial, Marie-Laure; Gambini, Luca; Noël, Alba; Hooper, John N A; Wood, Stephen A; Mellick, George D; Quinn, Ronald J

2014-06-10

440

Why are the Magnetic Field Directions Measured by Voyager 1 on Both Sides of the Heliopause so Similar?  

NASA Astrophysics Data System (ADS)

The solar wind carves a cavity in the interstellar plasma bounded by a surface, called the heliopause (HP), that separates the plasma and magnetic field of solar origin from those of interstellar origin. It is now generally accepted that in 2012 August Voyager 1 (V1) crossed that boundary. Unexpectedly, the magnetic fields on both sides of the HP, although theoretically independent of each other, were found to be similar in direction. This delayed the identification of the boundary as the HP and led to many alternative explanations. Here, we show that the Voyager 1 observations can be readily explained and, after the Interstellar Boundary Explorer (IBEX) discovery of the ribbon, could even have been predicted. Our explanation relies on the fact that the Voyager 1 and undisturbed interstellar field directions (which we assume to be given by the IBEX ribbon center (RC)) share the same heliolatitude (~34.°5) and are not far separated in longitude (difference ~27°). Our result confirms that Voyager 1 has indeed crossed the HP and offers the first independent confirmation that the IBEX RC is in fact the direction of the undisturbed interstellar magnetic field. For Voyager 2, we predict that the difference between the inner and outer magnetic field directions at the HP will be significantly larger than that observed by Voyager 1 (~30° instead of ~20°), and that the outer field direction will be close to the RC.

Grygorczuk, J.; Czechowski, A.; Grzedzielski, S.

2014-07-01

441

The Jet Propulsion Laboratory space exploration: Past, present and future  

NASA Astrophysics Data System (ADS)

The most recent scientific results from space exploration carried out by the Jet Propulsion Laboratory (JPL) are discussed. To aid understanding of these results, a brief background of JPL's history is presented, followed by a description of the Deep Space Network, JPL's system of antennas which communicates with spacecraft. The results from the missions of Voyager 1 and Voyager 2 are described. The atmosphere, rings, satellites and magnetospheres of Jupiter, Saturn, Uranus and Neptune are discussed with particular emphasis on novelty of the discoveries and the challenges encountered in explaining them. A brief discussion of the impact of spray research upon space exploration follows. This is because most recently launched missions used liquid fueled rockets to escape Earth's gravity. A summary of future missions and the National Aeronautics and Space Administration's new policies is presented in the conclusion.

Bellan, Josette

1993-02-01

442

Radio range measurements of coronal electron densities at 13 and 3.6 centimeter wavelengths during the 1988 solar conjunction of Voyager 2  

NASA Technical Reports Server (NTRS)

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 + or - 611/cu cm on ingress and 49688 + or - 983/cu cm on egress. These density levels are significantly higher than observed near previous solar maxima.

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.

1991-01-01

443

Forward and reverse shocks in the outer heliosphere: Observations from Voyager 2  

NASA Technical Reports Server (NTRS)

Observations from Voyager 2 as it moved from 10 to 14 deg S heliographic latitude in the period from 1992 through 1994 were used to gather statistics on the relative number of forward and reverse shocks. These results can be used to compare with observations from the Ulysses spacecraft which moved from 6 deg S to 70 deg S heliographic latitude during that time period. The Ulysses observations are in agreement with a 3-D, MHD model of the evolution of a steady tilted-dipole solar wind flow configuration prevalent in 1993. The model predicts and the Ulysses observations confirm a preponderance of reverse shocks at Ulysses latitudes poleward of streamer-belt latitudes. A preliminary scan of the Voyager data supports the complementary prediction of the model that forward fronts should dominate at large heliocentric distances near the heliographic equatorial plane during the same time period.

Lazarus, A. J.; Belcher, J. W.; Paularena, K. I.; Richardson, J. D.; Steinberg, J. T.; Pizzo, V. J.; Gosling, J. T.

1995-01-01

444

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

NASA Technical Reports Server (NTRS)

The characteristics and distribution of the small particles detected by the plasma-wave and radio-astronomy instruments during the Voyager 2 encounter with Uranus in January 1986 are examined. The nature of the observational data and the analysis techniques employed are discussed, and the results are presented in graphs. Particles of rms mass about 2.6 ng and radii of a few microns were found in an impact region of thickness 3840 km, with a maximum number density of 1600/cu m about 280 km from the equatorial plane, shortly after Voyager 2 crossed the plane of the Uranian rings. The possible origin of the particles in the rings or in small satellites outside the rings is considered.

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

1987-01-01

445

An experiment in the transportation of culturally significant plant propagules on Polynesian voyaging canoes  

NASA Astrophysics Data System (ADS)

The transportation of the most useful plants of Pacific Oceania allowed for the perpetuation of many ethnobotanical practices in Polynesian culture. One objective of this project was to look at different wrapping techniques of traditional cultigens on a voyage from Hawaii to Tahiti. Plant propagules were stored in both moist conditions using natural wrapping materials, and dry conditions using natural materials. A comparison of the survival rates of cultigens in moist conditions to dry conditions demonstrate no significant differences on a canoe voyage of 23 days. Further, the absence or presence of new growth on the cultigens did not vary significantly between these two variables. The second objective was to simulate this experiment in a project with high school students. By wrapping and storing canoe plant propagules on their canoe, then out planting them to observe viability, they combined the scientific method with an exploration of history.

Atkins, Alizon Z.

446

Satellites of Uranus - Disk-integrated photometry from Voyager imaging observations  

NASA Technical Reports Server (NTRS)

Voyager 2 imaging observations over a wide range of phase angles are used to determine the fundamental photometric parameters for the five largest satellites of Uranus. Over the spectral range covered by Voyager cameras (approximately 350-600 nm) the disk-averaged colors are moderately gray (no redder than the spectrum of Saturn's satellite Phoebe). Geometric albedos range from 0.19 for Umbriel to 0.40 for Ariel. Phase coefficients determined generally between phase angles of 10 and 60 deg vary from 0.021 mag/deg for Ariel to 0.028 mag/deg for Miranda. Phase integrals lie in the range of 0.5-0.65. The Bond albedos are about 0.1 for Umbriel and about 0.2 for the other satellites.

Veverka, J.; Thomas, P.; Helfenstein, P.; Brown, R. H.; Johnson, T. V.

1987-01-01

447

Jupiter Data Analysis Program: Analysis of Voyager wideband plasma wave observations  

NASA Technical Reports Server (NTRS)

Voyager plasma wave wideband frames from the Jovian encounters are analyzed. The 511 frames which were analyzed were chosen on the basis of low-rate spectrum analyzer data from the plasma wave receiver. These frames were obtained in regions and during times of various types of plasma or radio wave activity as determined by the low-rate, low-resolution data and were processed in order to provide high resolution measurements of the plasma wave spectrum for use in the study of a number of outstanding problems. Chorus emissions at Jupiter were analyzed. The detailed temporal and spectral form of the very complex chorus emissions near L = 8 on the Voyager 1 inbound passage was compared to both terrestrial chorus emissions as well as to the theory which was developed to explain the terrestrial waves.

Kurth, W. S.

1983-01-01

448

Cassini ENA images of the heliosheath and Voyager ``ground truth'': Thickness of the heliosheath  

NASA Astrophysics Data System (ADS)

Cassini/INCA (Ion and Neutral Camera) ENA images of the heliosheath, when combined with the ``ground truth'' of in situ measurements of ion intensities throughout the heliosheath obtained by Voyager/LECP (Low Energy Charged Particle Experiment), allow us to estimate a thickness parameter (L) along the two lines of sight (LOS) to the Voyager 1/2 spacecraft. The Compton-Getting effect due to the radial velocity of the heliosheath plasma is now taken into account. Our new estimates are LVGR1 = 31(+31,-18) AU and LVGR2 = 71(+30,-15) AU, so to the extent that our assumptions in deriving them are valid, the heliosheath appears to be twice as thick along the VGR2 LOS as it is along the LOS to VGR1.

Roelof, E. C.; Krimigis, S. M.; Mitchell, D. G.; Decker, R. B.; Dialynas, K.

2012-05-01

449

Absolute far-ultraviolet spectrophotometry of hot subluminous stars from Voyager  

SciTech Connect

Observations, obtained with the Voyager ultraviolet spectrometers, are presented of absolute fluxes for two well-known hot subluminous stars: BD + 28 deg 4211, an sdO, and G191 - B2B, a hot DA white dwarf. Complete absolute energy distributions for these two stars, from the Lyman limit at 912 A to 1 micron, are given. For BD + 28 deg 4211, a single power law closely represents the entire observed energy distribution. For G191 - B2B, a pure hydrogen model atmosphere provides an excellent match to the entire absolute energy distribution. Voyager absolute fluxes are discussed in relation to those reported from various sounding rocket experiments, including a recent rocket observation of BD + 28 deg 4211. 43 refs.

Holberg, J.B.; Ali, B.; Carone, T.E.; Polidan, R.S. (Arizona, University, Tucson (USA) NASA, Goddard Space Flight Center, Greenbelt, MD (USA))

1991-07-01

450

Absolute far-ultraviolet spectrophotometry of hot subluminous stars from Voyager  

NASA Technical Reports Server (NTRS)

Observations, obtained with the Voyager ultraviolet spectrometers, are presented of absolute fluxes for two well-known hot subluminous stars: BD + 28 deg 4211, an sdO, and G191 - B2B, a hot DA white dwarf. Complete absolute energy distributions for these two stars, from the Lyman limit at 912 A to 1 micron, are given. For BD + 28 deg 4211, a single power law closely represents the entire observed energy distribution. For G191 - B2B, a pure hydrogen model atmosphere provides an excellent match to the entire absolute energy distribution. Voyager absolute fluxes are discussed in relation to those reported from various sounding rocket experiments, including a recent rocket observation of BD + 28 deg 4211.

Holberg, J. B.; Ali, B.; Carone, T. E.; Polidan, R. S.

1991-01-01

451

Carbon-14 dating of an iron bloom associated with the voyages of Sir Martin Frobisher  

SciTech Connect

This paper recounts the history of the iron bloom associated with the English Elizabethan explorer Sir Martin Frobisher who made 3 voyages to the North American mainland in the 1570's. Specifically the paper deals with the use of proportional counters in carbon-14 dating of the Frobisher iron bloom which is located at the Smithsonian Institution. The procedures for preparing the samples for counting are described. (KRM)

Sayre, E.V. (Brookhaven National Lab., Upton, NY); Harbottle, G.; Stoenner, R.W. Washburn, W.; Olin, J.S.; Fitzhugh, W.

1982-01-01

452

Heliospheric magnetic field strength out to 66 AU: Voyager 1, 1978-1996  

Microsoft Academic Search

We discuss Voyager 1 (V1) observations of the heliospheric magnetic field strength from 1978 through 1996. During this period the distance of V1 from the Sun increased from ~3 AU to 66 AU and its heliographic latitude increased from ~5°S to 33°N. The magnetic field strength profile observed by V1 is consistent with Parker's spiral field model when one considers

L. F. Burlaga; N. F. Ness; Y.-M. Wang; N. R. Sheeley

1998-01-01

453

Heliospheric magnetic field strength out to 66 AU: Voyager 1, 1978–1996  

Microsoft Academic Search

We discuss Voyager 1 (V1) observations of the heliospheric magnetic field strength from 1978 through 1996. During this period the distance of V1 from the Sun increased from 3 AU to 66 AU and its heliographic latitude increased from 5øS to 33øN. The magnetic field strength profile observed by V1 is consistent with Parker's spiral field model when one considers

L. F. Burlaga; N. F. Ness; Y.-M. Wang; N. R. Sheeley

1998-01-01

454

A Study of Saturn's E-Ring Particles Using the Voyager 1 Plasma Wave Instrument  

NASA Technical Reports Server (NTRS)

The flyby of Voyager 1 at Saturn resulted in the detection of a large variety of plasma waves, e.g., chorus, hiss, and electron cyclotron harmonics. Just before the outbound equator crossing, at about 6.1 R(sub s), the Voyager 1 plasma wave instrument detected a strong, well-defined low-frequency enhancement. Initially it was suggested that plasma waves might be responsible for the spectral feature but more recently dust was suggested as at least a partial contributor to the enhancement. In this report we present evidence which supports the conclusion that dust contributes to the low-frequency enhancement. A new method has been used to derive the dust impact rate. The method relies mainly on the 16-channel spectrum analyzer data. The few wide band waveform observations available (which have been used to study dust impacts during the Voyager 2 ring plane crossing) were useful for calibrating the impact rate from the spectrum analyzer data. The mass and, hence, the size of the dust particles were also obtained by analyzing the response of the plasma wave spectrum analyzer. The results show that the region sampled by Voyager 1 is populated by dust particles that have rms masses of up to few times 10(exp -11) g and sizes of up to a few microns. The dust particle number density is on the order of 10(exp -3) m(exp 3). The optical depth of the region sampled by the spacecraft is 1.04 x 10(exp -6). The particle population is centered about 2500 km south of the equatorial plane and has a north-south thickness of about 4000 km. Possible sources of these particles are the moons Enceladus and Tethys whose orbits lie within the E-ring radial extent. These results are in reasonable agreement with photometric studies and numerical simulations.

Tsintikidis, D.; Kurth, W. S.; Gurnett, D. A.; Barbosa, D. D.

1993-01-01

455

Io’s Hot Plasma Torus—A Synoptic View from Voyager  

Microsoft Academic Search

A study of the morphology of Io's hot plasma torus has encompassed hundreds of Voyager UVS measurements of torus intensity. The long-term average stateøof the torus can be characterized by an axial asymmetry in the brightness of the prominent SIII 685-A feature manifested as an enhancement in brightness whose peak is fixed near 1900 local time. No long-term correlation of

B. R. Sandel; A. L. Broadfoot

1982-01-01

456