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1

The Voyager Journey to Interstellar Space  

NASA Astrophysics Data System (ADS)

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

Stone, E. C.

2

Planning Space Shuttle's maiden voyage  

NASA Technical Reports Server (NTRS)

NASA's first Space Shuttle, Columbia, whose technological advances include a space laboratory, navigational and communication satellites, and planetary explorers, is examined, and the first few flights, scheduled for 1980, are described. The Shuttle employs an all-digital, all-electronic, computer-operated avionics system. The onboard data processing and software subsystem, encompassing five computers (four online and one backup), a data-bus network, bus terminals, and software, is analyzed in detail. Attention is given to the basic structure of the Orbiter (37.19 m in length and 23.77 m wingspan), its main engines, and the payload and cargo capacities (29,500 kg). A two-step program that could increase the power and duration of spaceflights is presented. The first step is the creation of a power extension package, using solar arrays, generating electricity to extend the basic five-day flight to 20 days, while the second step uses the same design to create a 25-kW power model capable of providing energy for a 50-day flight. Plans for construction of a manned space construction base and a larger power platform of 250 kW are also presented.

Malkin, M. S.; Freitag, R. F.

1979-01-01

3

Space Probe Launch  

NASA Technical Reports Server (NTRS)

Managed by Marshall Space Flight Center, the Space Tug was a reusable multipurpose space vehicle designed to transport payloads to different orbital inclinations. Utilizing mission-specific combinations of its three primary modules (crew, propulsion, and cargo) and a variety of supplementary kits, the Space Tug was capable of numerous space applications. This 1970 artist's concept depicts the Tug's propulsion module launching a space probe into lunar orbit.

1970-01-01

4

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

5

Future studies of planetary rings by space probes  

NASA Technical Reports Server (NTRS)

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

Stone, E. C.

1984-01-01

6

Helios-Voyager cooperation for the investigation of the interplanetary space  

NASA Technical Reports Server (NTRS)

The planning of a joint mission involving the two Helios spacecraft and the two Voyager spacecraft is reported. During late fall 1977 the position of the four spacecraft facilitated correlation measurements as part of an investigation of interplanetary space in the vicinity of the earth. The spacecraft and their orbits are described, and the benefits that could result from future joint missions are considered.

Porsche, H.; Kehr, J.

1978-01-01

7

Exploring the Planets: Voyager  

NSDL National Science Digital Library

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

8

The navigation of space probes  

NASA Technical Reports Server (NTRS)

A new navigational method combining electronic measurement procedures and celestial mechanics makes it possible to conduct a space probe very close to a desired point in the neighborhood of a remote planet. Approaches for the determination of the position of the space probe in space are discussed, giving attention to the effects of errors in the employed data. The application of the navigational methods in a number of space missions is also considered.

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

1974-01-01

9

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

10

Nick Sagan Reflects on Voyager 1 and the Golden Record  

NASA Astrophysics Data System (ADS)

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

Showstack, Randy

2013-10-01

11

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

12

The Voyager interstellar mission  

NASA Technical Reports Server (NTRS)

The life expectancy of the Voyager spacecraft as they enter interstellar space, and what they will find along the way, are examined. The range of options available to mission planners as to which instruments to keep alive and which to shut off for the interstellar voyage is addressed. The way that the spacecraft will be operated in interstellar space is described.

Finnerty, Dan F.

1989-01-01

13

Your Mission: Investigate the geographical features on Venus and map the locations of space missions to Venus using a computer mapping program called Jules Verne Voyager  

E-print Network

1 Your Mission: Investigate the geographical features on Venus and map the locations of space missions to Venus using a computer mapping program called Jules Verne Voyager Venus. Your Task: 1. Using the internet, navigate to the following webpage: http://jules.unavco.org/Voyager/Venus

Smith-Konter, Bridget

14

Galileo Space Probe News Conference  

NASA Astrophysics Data System (ADS)

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

1996-01-01

15

Gravity Probe B Space Vehicle  

NASA Technical Reports Server (NTRS)

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

2003-01-01

16

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

17

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

18

Megabit memory for Helios space probe  

Microsoft Academic Search

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

M. Florjancic; H. Reiner

1974-01-01

19

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

20

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

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

Voyager 2 Jupiter encounter  

NASA Technical Reports Server (NTRS)

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

1979-01-01

23

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

24

Encounter with Jupiter. [Pioneer 10 space probe  

NASA Technical Reports Server (NTRS)

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

1975-01-01

25

Ka band TWTA for space probes  

Microsoft Academic Search

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

F. Andre; A. Gallien; P. Boone

2003-01-01

26

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

27

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

28

Exploring the Galaxy using space probes  

E-print Network

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

Rasmus Bjoerk

2007-04-23

29

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.

30

Galileo Space Probe News Conference. Part 1  

NASA Technical Reports Server (NTRS)

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

1996-01-01

31

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

32

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

33

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

34

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

35

Voyager's decade of wonder  

SciTech Connect

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

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

1989-07-01

36

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

37

Fantastic Voyage  

NSDL National Science Digital Library

To creatively illustrate a trip through the human body functions through the investigation of the different organ systems, students work in teams of 3 to 4 to produce the items listed below that will be used to create the various "ports of call" on our FANTASTIC VOYAGE. The classes are divided into groups and each group will work on a different part of the "trip." The majority of the work will be done in class during the week before the "departure date." Students usually find it necessary to do some individual work at home in order to accomplish all of the tasks assigned to each group. Each group produces a fact sheet, a 3D model and some kind of "grabber" to attract people to their display which they set up for an evening exhibition for their parents and the public. Each group elects individuals to fulfill specified roles on the team, but each member of the team is required to participate in all aspects of the work.

BEGIN:VCARD VERSION:2.1 FN:Judith L. Allard N:L. Allard; Judith ORG:Burlington High School REV:2005-04-10 END:VCARD

1995-06-30

38

Optical Checkout of Large Antennas for Deep Space Probes  

Microsoft Academic Search

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

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

1963-01-01

39

The Voyager Interstellar Mission  

NASA Technical Reports Server (NTRS)

Voyager 2's successful encounter with Neptune in August of 1989 marked the completion of the Grand Tour of the outer solar system by Voyager 1 and 2. In actuality, however, it is but a beginning. Both spacecraft have entered a new exploratory phase known as the Voyager Interstellar Mission or VIM. This journey ultimately may prove as enlightening and ennobling as the Voyager's planetary encounters during their first twelve years in flight.

Robinett, Karen H.

1990-01-01

40

Reacting to nuclear power systems in space: American public protests over outer planetary probes since the 1980s  

NASA Astrophysics Data System (ADS)

The United States has pioneered the use of nuclear power systems for outer planetary space probes since the 1970s. These systems have enabled the Viking landings to reach the surface of Mars and both Pioneers 10 and 11 and Voyagers 1 and 2 to travel to the limits of the solar system. Although the American public has long been concerned about safety of these systems, in the 1980s a reaction to nuclear accidents - especially the Soviet Cosmos 954 spacecraft destruction and the Three Mile Island nuclear power plant accidents - heightened awareness about the hazards of nuclear power and every spacecraft launch since that time has been contested by opponents of nuclear energy. This has led to a debate over the appropriateness of the use of nuclear power systems for spacecraft. It has also refocused attention on the need for strict systems of control and rigorous checks and balances to assure safety. This essay describes the history of space radioisotope power systems, the struggles to ensure safe operations, and the political confrontation over whether or not to allow the launch the Galileo and Cassini space probes to the outer planets. Effectively, these efforts have led to the successful flights of 12 deep space planetary probes, two-thirds of them operated since the accidents of Cosmos 954, Three Mile Island, and Chernobyl.

Launius, Roger D.

2014-03-01

41

Some Aspects of Satellite and Space Probe Reliability  

Microsoft Academic Search

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

T. W. Gross; H. C. Werner

1961-01-01

42

Aerodynamics problems of space probes in comet atmosphere  

Microsoft Academic Search

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

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

1985-01-01

43

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

NASA Technical Reports Server (NTRS)

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

1979-01-01

44

Voyage of the Challenger  

NSDL National Science Digital Library

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

45

Novel Time Synchronization techniques for Deep Space Probes  

Microsoft Academic Search

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

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

2009-01-01

46

The Voyager flights to Jupiter and Saturn  

NASA Astrophysics Data System (ADS)

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

1982-07-01

47

The Voyager flights to Jupiter and Saturn  

NASA Technical Reports Server (NTRS)

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

1982-01-01

48

Autonomy capabilities of European deep space probes  

Microsoft Academic Search

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

Klaus Schilling; J. Lafontaine; Hubert Roth

1996-01-01

49

Stellar occultation probes of the Uranian rings at 0.1 and 2.2 microns - A comparison of Voyager UVS and earth-based results  

NASA Technical Reports Server (NTRS)

A comparison between Voyager 2 UV spectrometer data for stellar occultations of the Uranian ring system obtained at 0.11 microns and 2.2-micron earth-based occultation data reveals the anticipated factor-of-two reduction in observed optical depths relative to those observed from earth. This is due to Voyager's proximity to the rings, which allows light diffracted out of the direct beam by ring particles to be replaced by light diffracted into the direct beam light from other particles, and further permits the placing of firm lower limits on typical particle sizes of 0.3 and 1 cm for the epsilon and delta rings, respectively. As a function of true anomaly, the epsilon ring profile is noted to remain very similar in shape and essentially constant in equivalent depth, even very near periapse.

Holberg, J. B.; Nicholson, P. D.; French, R. G.; Elliot, J. L.

1987-01-01

50

Voyage to Jupiter.  

ERIC Educational Resources Information Center

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

Morrison, David; Samz, Jane

51

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

52

Médecine des voyages  

PubMed Central

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

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

2014-01-01

53

Solar system as space-probe  

Microsoft Academic Search

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

W. H. McCrea

1975-01-01

54

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.

2012-06-26

55

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

E-print Network

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

Paulos, Eric

56

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

57

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

58

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

59

Voyager 1 View of Callisto  

NASA Technical Reports Server (NTRS)

Voyager 1 took this picture of Callisto during Voyager's approach to Jupiter's outer large satellite in 1979. Both Galileo and Marius discovered Callisto in 1610. In Greek mythology, Callisto was a nymph loved by Zeus and thus hated by Hera. Hera turned her into a bear, which Zeus placed in the heavens as the constellation Ursa Major. Voyager was 350,000 kilometers from Callisto and took this picture that shows features about seven kilometers wide across the surface. Callisto is a little smaller than Ganymede (Callisto is about the size of Mercury) and it seems that it is composed of a mixture of ice and rock (about 40 percent ice and 60 percent rock and iron). The darker color of Callisto (about half as reflective as Ganymede but still twice as bright as the Moon) implies that the upper surface is 'dirty ice' or water- rich rock frozen on Callisto's cold surface (approximately -243 Fahrenheit degrees at the equator). Callisto's atmosphere is mostly carbon dioxide. Far more craters appear on the surface of Callisto than on the surface of Ganymede, leading scientists to believe that Callisto is the oldest of the Galilean satellites. Callisto could date back as far as four billion years ago and has remained relatively unchanged in the history of space.

1979-01-01

60

C over: Voyager 2 WilS one rniliion  

E-print Network

Uranus and on course for Neptune when the wicin-angle Ciirnera took. this photog rClph of Uranus. Uranus' pale blue- grt!cn color, noted bV wouna based obsorvf'rs ar.d recorded In eilrll .r Voyager,the Voyager 2 Uranus encounter began and the Galt/eo spacecraft was shipped to Kennedy Space Center

Waliser, Duane E.

61

Gravitational Experiments in Space: Gravity Probe B and STEP  

Microsoft Academic Search

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

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

2004-01-01

62

Mission to Jupiter. [Pioneer 10 and 11 space probes  

NASA Technical Reports Server (NTRS)

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

1975-01-01

63

The Evolving Space Weather System—Van Allen Probes Contribution  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

64

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

65

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

66

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

67

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

68

Has Voyager 1 left the heliosphere?  

NASA Astrophysics Data System (ADS)

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

Wendel, JoAnna

2014-11-01

69

Primary processing of magnetic field data aboard a space probe  

Microsoft Academic Search

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

D. Lenners; H. J. Linthe

1987-01-01

70

Voyager Saturn encounter press briefing  

NASA Technical Reports Server (NTRS)

The briefing reviewed the mission planning of the Voyager project. The near encounter trajectories of both Voyager spacecraft were examined. The Saturn system is discussed with particular emphasis on Saturn's moons.

1980-01-01

71

The Gulf Stream Voyage  

NSDL National Science Digital Library

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

2000-01-01

72

The Huygens probe—space history in many ways  

NASA Astrophysics Data System (ADS)

The European Space Agency's Huygens probe, developed under the prime contractorship of Alcatel Alenia Space, has on the 14th January 2005 arrived at its final destination, Saturn's largest Moon Titan. This event provides a major step in our solar system exploration activities and represents a significant contribution to the exploration of Titan, an Earth-like body in many respects. The road to its destination has been long and eventful, though after launch in 1997 comfortably attached to the mighty Cassini spacecraft. Up to the very last minute before the Cassini Huygens separation event, intensive efforts in agencies and industry have continued to ensure the overall Huygens probe performance with renewed knowledge of among others, the Titan atmospheric conditions. In parallel, dedicated in-flight test campaigns, supported by complementary ground-tests, and extensive system health assessments have been executed very frequently, providing the knowledge of perfect functionality and health of all probe sub-systems and science instruments upon the moment of separation from Cassini, end of 2004. This paper describes the Huygens programme schedule, with emphasis on that of the last few years before the arrival, together with the challenges of getting ready for mission success. Programme lessons learnt are discussed, stemming from Huygens mission inherent features such as the long dormant duration due to the 7-year cruise phase, evolution of knowledge of the mission's environment and a late anomaly discovery.

Schipper, Anne Marie; Lebreton, Jean-Pierre

2006-07-01

73

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.

74

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

75

Page 1 Frame-Dragging, Cryogenics & Space: The Gravity Probe B Experiment 7th Appleton Space Conference, Rutherford Appleton Laboratory (RAL) 8 December 2011  

E-print Network

Page 1 Frame-Dragging, Cryogenics & Space: The Gravity Probe B Experiment 7th Appleton Space-Dragging, Cryogenics & Space Rutherford Appleton Laboratory (RAL) The Gravity Probe B Experiment 7th Appleton Space Conference #12;Page 2 Frame-Dragging, Cryogenics & Space: The Gravity Probe B Experiment 7th Appleton Space

76

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

77

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).

78

Voyager 1 observes sudden changes in cosmic ray intensity  

NASA Astrophysics Data System (ADS)

The Voyager 1 spacecraft, which was launched in 1977, has reached a new region of space near the edge of the heliosphere, the bubble of charged particles surrounding our solar system. At the edge of the heliosphere is the heliosheath, the region where the solar wind slows down as it hits incoming particles from the interstellar medium. As it traveled through the heliosheath, Voyager 1 recently encountered a dramatic, unprecedented change in the intensity of cosmic rays.

Balcerak, Ernie

2013-06-01

79

Voyager at Uranus  

NASA Technical Reports Server (NTRS)

The engineering changes that had to be made in the Voyager 2 spacecraft in order to enable it to fly beyond the originally planned encounters with Jupiter and Saturn and the underlying engineering strategy leading to the encounter with Uranus are discussed. Fixes of the azimuth actuator failure, receiver failure, and memory failure, and capability upgrades of Image Data Compression, aperture augmentation protective coding, smear reduction, Image Motion Compensation, power management, and contingency planning are summarized. The use of the Computer Command Subsystem in the extension of the voyage is described. The ways in which the strategic priorities, including spacecraft preservation, protection of the near-encounter load, development of new ground and spacecraft capabilities, and repair or circumvention of existing spacecraft faults, were accomplished are reviewed, and the accomplishment of additional tasks is also discussed.

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

1986-01-01

80

Triton - Voyager's finale  

NASA Technical Reports Server (NTRS)

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

Brown, R. H.

1992-01-01

81

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

82

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

83

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

84

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

85

Voyager 25th Anniversary Poster  

NSDL National Science Digital Library

This poster was developed to commemorate the 25th anniversary of the Voyager 1 and 2 launch. The learning objectives of the activity Voyager 1 and 2: Where Are You is to help students appreciate the great distances between the planets and their comparable sizes, view the solar system in three dimensions in a useful scale, and visualize the paths of the Voyager spacecraft and their distances and positions.

86

46 CFR Sec. 2 - Voyage numbers.  

Code of Federal Regulations, 2011 CFR

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

2011-10-01

87

46 CFR Sec. 2 - Voyage numbers.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

88

46 CFR Sec. 2 - Voyage numbers.  

Code of Federal Regulations, 2014 CFR

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

2014-10-01

89

46 CFR Sec. 2 - Voyage numbers.  

Code of Federal Regulations, 2012 CFR

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

2012-10-01

90

46 CFR Sec. 2 - Voyage numbers.  

Code of Federal Regulations, 2013 CFR

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

2013-10-01

91

Electric Field Double Probe Measurements for Ionospheric Space Plasma Experiments  

NASA Technical Reports Server (NTRS)

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

Pfaff, R.

1999-01-01

92

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

93

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

E-print Network

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

Atreya, Sushil

94

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

Microsoft Academic Search

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

Stefan Zegenhagen; Andreas Werner; Arthur Weller; Thomas Klinger

2006-01-01

95

Voyager 1 examines Jupiter  

NASA Technical Reports Server (NTRS)

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

1979-01-01

96

Voyage to Kure  

NSDL National Science Digital Library

The documentary film "Voyage to Kure" follows Jean-Michel Cousteau's team expedition to the Northwestern Hawaiian Islands, chronicling "the exploration of one of the last pristine coral reefs in the Pacific, a glimpse of paradise before the people." In this Web site from Ocean Futures Society, visitors can follow the expedition online with reports from the field, photos, and more. The site also includes links to the Web sites of state and federal agencies that worked with Ocean Futures Society on the film -- a good place to start for learning more about the islands and their unique coral reef ecosystems.

97

Jules Verne Voyager, Jr.  

NSDL National Science Digital Library

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

Chuck Meertens

98

Voyager 1: Encounter with Jupiter  

NASA Technical Reports Server (NTRS)

An overview of the Voyager is presented along with samples of the nearly 19,000 photographs returned by Voyager 1 spacecraft at the midpoint of its 38-month mission to Jupiter and Saturn. Particular emphasis is given to color photographs of the Great Red Spot, and the surface features of the Gallilean satellites.

1979-01-01

99

k-space investigations of an adiabatic nanofocusing SNOM probe , S.F. Becker1  

E-print Network

k-space investigations of an adiabatic nanofocusing SNOM probe M. Esmann1 , S.F. Becker1 , K.W. Yoo. To investigate the angular distribution of near-fields at the tip apex, a k- space imaging technique [3 to imaging of plasmonic nanostructures and investigate the near-field coupling between probe and sample. Fig

Park, Namkyoo

100

Voyager Spacecraft Moves Towards Edge of Solar System  

NSDL National Science Digital Library

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

Grinnell, Max

101

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

102

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.

Juliana Texley

2008-07-01

103

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

104

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

105

First steps of processing VLBI data of space probes with VieVS L. Plank, J. Bohm, H. Schuh  

E-print Network

First steps of processing VLBI data of space probes with VieVS L. Plank, J. B¨ohm, H. Schuh to process VLBI data received from transmitters within the solar system, e.g. space probes. Up to now frame ties between the dy- namic reference frame of a space probe and the kinematically defined

Schuh, Harald

106

Study of space-charge effects on dielectric breakdown of polymers by direct probing  

Microsoft Academic Search

Direct and quantitative probing of space charge was carried out to study effects of space charge on dielectric breakdown of polymeric insulating materials. In poly-p-phenylene sulfide, in which dielectric-breakdown characteristics were explained in terms of space-charge formation, positive homo space charge was observed. The amount and the depth of space charge detected could explain the dependence of impulse breakdown strength

Yasuo Suzuoki; Yohji Matsukawa; Sang-Ok Han; Akihiro Fujii; Jong-Seok Kim; Teruyoshi Mizutani; M. Ieda; N. Yoshifuji

1992-01-01

107

Study of space charge effects on electrical properties of polymers by direct probing  

Microsoft Academic Search

Direct and quantitative probing of space charge was carried out to study the effects of space charge on the dielectric breakdown of polymeric insulating materials. In poly-p-phenylene sulfide, in which dielectric-breakdown characteristics were explained in terms of space-charge formation, positive homo space charge was observed. The amount and the depth of space charge detected agreed well with those assumed from

Y. Suzuoki; Y. Matsukawa; S. O. Han; A. Fujii; T. Mizutani; M. Ieda; N. Yoshifuji

1991-01-01

108

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

109

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

110

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

111

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

112

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

NASA Technical Reports Server (NTRS)

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

Parsons, P.

1974-01-01

113

46 CFR 80.15 - Ocean voyage.  

Code of Federal Regulations, 2012 CFR

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

2012-10-01

114

46 CFR 80.15 - Ocean voyage.  

Code of Federal Regulations, 2014 CFR

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

2014-10-01

115

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

116

46 CFR 80.15 - Ocean voyage.  

Code of Federal Regulations, 2011 CFR

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

2011-10-01

117

Sources concerning Christopher Columbus's second voyage  

Microsoft Academic Search

Christopher Columbus's second voyage was, from a historical point of view, as important as the first even if less sensational.\\u000a It was indeed this voyage which created the bridge between native and European culture. This article discusses the main sources\\u000a concerning Columbus's second voyage with particular reference to the documents existing in Italian libraries.

L. Laurencich Minelli

1987-01-01

118

46 CFR 80.15 - Ocean voyage.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

119

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

Microsoft Academic Search

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

Robert Newton

1960-01-01

120

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

121

MARINER 9 SPACE PROBE UNDERGOES FINAL CHECKS PRIOR TO ENCAPSULATION  

NASA Technical Reports Server (NTRS)

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

1971-01-01

122

Vacuum Fluctuations as Quantum Probes in FRWL space-times  

E-print Network

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

Sergio Zerbini

2014-11-03

123

Probing Galactic Dynamics with the Space Interferometry Mission  

Microsoft Academic Search

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

Stephen C. Unwin

1998-01-01

124

Surface acoustic wave probing with spaced interdigital transducers  

Microsoft Academic Search

We have found that interdigital surface acoustic wave (SAW) transducers deposited on glass substrates and positioned very close to a piezoelectric crystal delay line surface (’’spaced transducers’’) may be used to simulate identical transducers fabricated directly on the surface, for pretesting and prealignment of SAW devices. A novel spaced transducer mounting technique has been developed that utilizes a free floating

W. L. Bond; C. M. Fortunko; S. L. Quilici; H. J. Shaw; J. Souquet

1977-01-01

125

Surface acoustic wave probing with spaced interdigital transducers  

Microsoft Academic Search

We have found that interdigital surface acoustic wave (SAW) transducers deposited on glass substrates and positioned very close to a piezoelectric crystal delay line surface (''spaced transducers'') may be used to simulate identical transducers fabricated directly on the surface, for pretesting and prealignment of SAW devices. A novel spaced transducer mounting technique has been developed that utilizes a free floating

W. L. Bond; C. M. Fortunko; S. L. Quilici; H. J. Shaw; J. Souquet

1977-01-01

126

november 2009 Darwin Virtual Voyage  

E-print Network

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

Papautsky, Ian

127

European Space Agency studies of the solar probe  

NASA Technical Reports Server (NTRS)

The feasibility and scientific objectives of a solar probe were studied by a Mission Definition Group in 1975 and 1976. The orbit analysis program was developed and an extended study of the orbit analysis was done in 1977. The results of these studies are in the Report of the Mission Definition Study (1976) and an E.S.O.C. report (1978), and the reader is referred to these sources for greater details. In this report, only brief discussion on mission concept and objectives, satellite design, orbit, orbit analysis, are presented.

Roxburgh, I. W.

1978-01-01

128

Has Voyager 1 really crossed the heliopause?  

NASA Astrophysics Data System (ADS)

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

Gloeckler, G.; Fisk, L. A.

2015-01-01

129

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

130

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

131

Probing Chemical Space with Alkaloid-Inspired Libraries  

PubMed Central

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

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

2014-01-01

132

Probing chemical space with alkaloid-inspired libraries  

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

133

Engine-driven generators for deep space probes  

Microsoft Academic Search

Summarizes important developments relating to power for deep space missions. The important alternatives to thermocouples for converting radioisotope heat into electric power are Stirling engines, alkali-metal thermal-to-electric converters (AMTEC), thermionic converters, and thermo-photovoltaic converters. The operating principles and limitations of these converters are described.

Henry Oman

2002-01-01

134

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

NASA Astrophysics Data System (ADS)

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

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

2008-09-01

135

IEC Thrusters for Space Probe Applications and Propulsion  

Microsoft Academic Search

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

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

2009-01-01

136

Improved concatenated coding\\/decoding for deep space probes  

Microsoft Academic Search

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

Dale C. Linne von Berg; Stephen G. Wilson

1992-01-01

137

Probing Planckian physics in de Sitter space with quantum correlations  

E-print Network

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

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

2014-11-15

138

Probing Planckian physics in de Sitter space with quantum correlations  

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

139

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

140

Voyager 1 measures electron intensity in the outer heliosphere  

NASA Astrophysics Data System (ADS)

The Voyager 1 spacecraft is exploring the outer heliosheath past about 111 astronomical units from the Sun. The heliosheath is the region where the outgoing solar wind is slowed by the interstellar medium. The Voyager spacecraft have been sending back interesting new information about the structure of this previously uncharted boundary region at the edge of the solar system. Webber et al. now report that Voyager 1 recently observed two sudden increases in the intensity of low-energy cosmic ray electrons as it traveled farther from the Sun. At the outer boundary of the heliosheath, the electron intensity is usually assumed to be equal to that in interstellar space, outside the heliosphere. The authors suggest that the sudden changes in electron intensity are evidence of significantly different regions in the structure of the outer heliosheath and that as of early 2012, Voyager 1 had not quite reached the undisturbed interstellar medium outside of the heliosheath. (Geophysical Research Letters, doi:10.1029/2012GL051171, 2012)

Balcerak, Ernie

2012-05-01

141

First Close-up Image of Jupiter from Voyager 1  

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 is really a combination of three images taken through color filters, then transmitted to Jet Propulsion Laboratory through the Deep Space Network's antennas, and assembled by JPL's Image Processing Lab. The Voyager Project is managed for NASA by Caltech's Jet Propulsion Laboratory.

1979-01-01

142

An Intergalactic Voyage.  

ERIC Educational Resources Information Center

Describes an event called Star Week that involved families joining in their children's projects, attending an educational presentation by the National Aeronautics and Space Administration (NASA), and participating in a schoolwide star party. Contains resources for both students and teachers. (JRH)

Wethered, Peggy Ann

1997-01-01

143

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

SciTech Connect

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

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

2012-05-15

144

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

PubMed

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

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

2012-05-01

145

Space probe/satellite ejection apparatus for spacecraft  

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

146

Space probe/satellite ejection apparatus for spacecraft  

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

147

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

148

MARINER 8 SPACE PROBE'S SOLAR ARRAYS ARE INSTALLED  

NASA Technical Reports Server (NTRS)

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

1971-01-01

149

Voyager 1: Encounter with Saturn  

NASA Technical Reports Server (NTRS)

The history of the Voyager Project is reviewed as well as known facts about Saturn and its satellites. Important results of encounters with Jupiter are summarized. Scientific objectives of the flyby of Saturn involve the planet's atmosphere, rings, and magnetic field interactions with the solar wind and satellites. The search for additional satellites, and various aspects of Titan, Rhea, Dione, Mimas, Iapetus, Hyperion, and Enceladas are also of interest. The instruments developed to obtain these goals are described.

Panagakos, N.

1980-01-01

150

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

151

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

152

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

E-print Network

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

Yu. A. Portnov

2012-04-24

153

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

Microsoft Academic Search

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

E. R. Kursinski

154

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

Microsoft Academic Search

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

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

155

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

E-print Network

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

156

Farewell to the Voyagers: Measuring the Local ISM in the Immediate Path of the Two Voyager Spacecraft  

NASA Astrophysics Data System (ADS)

Astronomical observations of the interstellar medium often struggle to measure fundamental physical properties of the gas on small scales because most observations are averaged along the line of sight, leading to difficulties in evaluating pressure equilibrium, turbulence, magnetic field structure, and volume density. The local ISM has helped in this regard by providing relatively simple ISM absorption profiles over short path lengths, with low column densities only detectable with strong transitions in the UV . On August 25, 2012, the first human-made object, the Voyager 1 spacecraft, crossed the heliosphere, effectively leaving the solar system and entering the galactic interstellar environment. Voyager 2 is expected to do the same in the coming years, and over the next decade both spacecraft will continue to make daily measurements of fundamental physical properties. We propose to make the first observations of nearby stars along the same line of sight as the current locations of the Voyager spacecraft in order to measure the same interstellar material. The proposed observations are of the very closest stars in these directions and will provide measurements of the kinematic structure, electron density, temperature and turbulence, elemental abundances and small scale structure by comparing two closely spaced sight lines. With both HST and the Voyager spacecraft approaching the end of long and fruitful missions, we have the opportunity to acquire a unique dataset which synthesizes the independent and complimentary in situ observations with the shortest possible line-of-sight observations, to provide an unprecedented study of the galactic ISM surrounding the Sun.

Redfield, Seth

2014-10-01

157

Laser-light sailing and non-stationary power stations applied to robotic star probes  

Microsoft Academic Search

The light sail has emerged as a leading contender to propel extrasolar expeditions. Because solar-sail performance is limited by the inverse-square law, one-way expeditions to other stars requiring voyage durations of a few centuries or less may be propelled by radiation pressure from a laser beam originating from a location closer to the Sun than the space probe. Maintaining a

Gregory L. Matloff

2000-01-01

158

Voyage of Discovery - Duration: 1:35.  

NASA Video Gallery

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

159

Probing the supersymmetric parameter space by weakly interacting massive particle direct detection  

NASA Astrophysics Data System (ADS)

We discuss to what extent the present experiments of direct search for weakly interacting massive particles (WIMPs), when interpreted in terms of relic neutralinos, probe interesting regions of the supersymmetric parameter space, which are also being progressively explored at accelerators. Our analysis is performed in a number of different supersymmetric schemes. We derive the relevant neutralino cosmological properties, locally and on the average in the universe. We prove that part of the supersymmetric (SUSY) configurations probed by current WIMP experiments entails relic neutralinos of cosmological interest. The main astrophysical and particle physics uncertainties, relevant for a proper comparison between theory and experimental data, are stressed and taken into account.

Bottino, A.; Donato, F.; Fornengo, N.; Scopel, S.

2001-06-01

160

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

161

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

162

Jupiter/Voyager data analysis  

NASA Technical Reports Server (NTRS)

The extent to which the unusual spectral properties of Io and Alamathea can be accounted for by sulfur glass or at least by sulfur rich glasses was investigated. Whether or not the temperature dependence of the characteristic spectrum of pure sulfur can be used to set limits on the abundance of sulfur as a surface constituent of Io was also explored. Data from Voyager imaging observations of Saturn's small satellites, of the unusual retrograde satellite Phoebe, and of Hyperion were also reduced, analyzed, and interpreted.

Veverka, J.

1985-01-01

163

Voyager at Neptune - A preliminary report  

SciTech Connect

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

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

1989-12-01

164

The Voyager encounter with Uranus and Neptune  

NASA Technical Reports Server (NTRS)

Voyager 2 approaches Uranus at a relative low phase angle and high southerly latitude. Only when the spacecraft is very close to Uranus does the geometry change appreciably. Most of the important observations occur within six hours of closest approach. Voyager flies through an Earth and solar occulation zone and leaves Uranus at a relatively high phase angle of about 145 degrees. There isn't much of an opportunity to look at the equatorial region of the planet. At Neptune, on the other hand, the approach is more nearly equatorial (about 35 deg S lat). Voyager 2 will come much closer to Nepture than to any of the other gas giants as it skims within about 2000 km of Neptune's cloudtops. It will pass through earth and solar occultation zones at both Neptune and its satellite, Triton. Again, Voyager 2 will leave Neptune at about 35 deg S latitude. Voyager operational instrument, interplanetary trajectories and planetary encounters are briefly discussed.

Miner, Ellis D.

1986-01-01

165

Prospects for the Voyager extra-planetary and interstellar mission  

NASA Technical Reports Server (NTRS)

An advance study has been conducted to examine the trajectory characteristics of Voyager 1 and 2 as they depart from the solar system and traverse interstellar space. A survey of the extraplanetary phase, commencing with completion of the final planetary encounters and ceasing with loss of spacecraft communication, considers the trajectory aspects attendant to a heliospheric investigation and possible sensing of a trans-Neptunian massive body. An analysis of departure telecommunications capability attempts to bound the inevitable time of communication loss. A study of the interstellar phase examines closest approaches of the spacecraft to the sun's stellar neighbours. A covariance analysis is provided to illustrate the statistical effect of stellar state uncertainties on these approaches. In addition to the Voyager spacecraft, data for Pioneers 10 and 11 are provided where appropriate.

Cesarone, R. J.; Sergeyevsky, A. B.; Kerridge, S. J.

1984-01-01

166

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

167

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

168

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

Microsoft Academic Search

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

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

1996-01-01

169

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

Microsoft Academic Search

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

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

1982-01-01

170

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

E-print Network

Planetary and Space Science 56 (2008) 586­600 Reconstruction of the trajectory of the Huygens probe. Colombo, University of Padova, Via Venezia 15, 35131 Padova, Italy b Center for Space Physics, Boston University, 725 Commonwealth Avenue, Boston, MA 02215, USA c Planetary and Space Sciences Research Institute

Withers, Paul

171

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

172

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

173

46 CFR 46.05-20 - Great Lakes voyage.  

Code of Federal Regulations, 2014 CFR

... 2 2014-10-01 2014-10-01 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...

2014-10-01

174

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

175

46 CFR 46.05-20 - Great Lakes voyage.  

Code of Federal Regulations, 2012 CFR

... 2 2012-10-01 2012-10-01 false Great Lakes voyage. 46.05-20 Section 46.05-20...Definitions Used in This Part § 46.05-20 Great Lakes voyage. A Great Lakes voyage is any voyage from a United States...

2012-10-01

176

46 CFR 46.05-20 - Great Lakes voyage.  

Code of Federal Regulations, 2011 CFR

... 2 2011-10-01 2011-10-01 false Great Lakes voyage. 46.05-20 Section 46.05-20...Definitions Used in This Part § 46.05-20 Great Lakes voyage. A Great Lakes voyage is any voyage from a United States...

2011-10-01

177

46 CFR 46.05-20 - Great Lakes voyage.  

Code of Federal Regulations, 2010 CFR

... 2 2010-10-01 2010-10-01 false Great Lakes voyage. 46.05-20 Section 46.05-20...Definitions Used in This Part § 46.05-20 Great Lakes voyage. A Great Lakes voyage is any voyage from a United States...

2010-10-01

178

Radio science experiment of Voyager-2 spacecraft occultation by Neptune  

NASA Technical Reports Server (NTRS)

NASA-JPL and Japan's Institute of Space and Astronautical Science collaborated at the Usuda Deep Space Center in the Voyager-2 Neptune occultation experiment. Phase information is extracted from the recorded data by means of a digital filter that can track the carrier frequency and narrow the filter bandwidth by up to 3 mHz. The results thus obtained can verify the phase-stability of the receiving system as a whole. Problems experienced by low-noise amplifiers were solved through the use of system redundancies.

Hayashi, T.; Nishimura, T.; Takano, T.; Yamamoto, Z.; Yamada, M.; Shuto, K.; Saito, H.; Ichikawa, T.; Kawashima, N.; Mizuno, E.

1990-01-01

179

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

E-print Network

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

Mukamel, Shaul

180

The Argonne Voyager multimedia server  

SciTech Connect

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

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

1997-07-01

181

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

182

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

183

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

184

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

NASA Technical Reports Server (NTRS)

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

1974-01-01

185

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

186

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

PubMed

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

Beebe; Simon; Huber

1996-05-10

187

Probing Dark Matter and Dark Energy with Space-Based Weak Lensing  

E-print Network

Weak lensing provides a direct measure of the distribution of mass in the universe, and is therefore a uniquely powerful probe of dark matter. Weak lensing can also be used to measure the twin phenomenon of dark energy, via its effect upon the cosmological growth rate of structures. Essential for this technique are well-resolved images of background galaxies out to large distances. As a concrete example of the surveys that will become available by the end of the decade, we consider the planned Supernova/Acceleration Probe (SNAP) space telescope. Detailed simulations of space-based images, manufactured using the shapelets formalism, enable us to quantitatively predict the future sensitivity to weak lensing shear. The high number density of galaxies resolved from space will enable maps of dark matter to be produced in two and three dimensions, with a resolution superior to that from the ground. Such observations will also afford reduced systematics for high-precision measurements of weak lensing statistics. These will be used to set tight constraints on cosmological parameters. In particular, the parameter for equation of state of dark energy, w, will be measured using weak lensing with a precision comparable to and somewhat orthogonal to constraints from other methods.

Richard Massey; Alexandre Refregier; Jason Rhodes

2004-03-10

188

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

189

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

E-print Network

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

Matthias Blau; Jelle Hartong; Blaise Rollier

2010-05-05

190

Interagency telemetry arraying for Voyager-Neptune encounter  

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

191

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

192

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

193

Voyages Through Time: Everything Evolves  

NASA Astrophysics Data System (ADS)

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

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

194

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

195

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

196

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

197

Voyager 2 Observes Energetic Electrons - Duration: 15 seconds.  

NASA Video Gallery

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

198

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

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...

199

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

200

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

E-print Network

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

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

2011-05-17

201

Scalar Field Probes of Power-Law Space-Time Singularities  

E-print Network

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

Matthias Blau; Denis Frank; Sebastian Weiss

2006-03-01

202

Group-galaxy correlations in redshift space as a probe of the growth of structure  

E-print Network

We investigate the use of the cross-correlation between galaxies and galaxy groups to measure redshift-space distortions (RSD) and thus probe the growth rate of cosmological structure. This is compared to the classical approach based on using galaxy auto-correlation. We make use of realistic simulated galaxy catalogues that have been constructed by populating simulated dark matter haloes with galaxies through halo occupation prescriptions. We adapt the classical RSD dispersion model to the case of the group-galaxy cross-correlation function and estimate the RSD parameter {\\beta} by fitting both the full anisotropic correlation function {\\xi}(rp, {\\pi}) and its multipole moments. In addition, we define a modified version of the latter statistics by truncating the multipole moments to exclude strongly non-linear distortions at small transverse scales. We fit these three observable quantities in our set of simulated galaxy catalogues and estimate statistical and systematic errors on {\\beta} for the case of galax...

Mohammad, Faizan G; Bianchi, Davide; Guzzo, Luigi; Peacock, John A

2015-01-01

203

Enhancing Resilience in Youth through a 10-Day Developmental Voyage  

ERIC Educational Resources Information Center

The present study sought to examine the potential for resilience to be enhanced in a group of youth participating in a developmental voyage, and to identify the factors that contribute to increased resilience following the voyage. Two studies are reported. Study 1 revealed that voyage participants experienced increased resilience over the course…

Hayhurst, Jill; Hunter, John A.; Kafka, Sarah; Boyes, Mike

2015-01-01

204

Voyager Reading Programs. What Works Clearinghouse Intervention Report  

ERIC Educational Resources Information Center

"Voyager Passport"[TM] is a supplemental reading intervention system for students in grades K-5. "Voyager Passport Reading Journeys"[TM] is a reading intervention program designed for adolescents who struggle with reading. The "Voyager Universal Literacy System"[R] is a K-3 reading program that includes a core reading curriculum; a progress…

What Works Clearinghouse, 2010

2010-01-01

205

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.

206

Modeling of Saturn's magnetosphere during Voyager 1 and Voyager 2 encounters  

NASA Astrophysics Data System (ADS)

We model Saturn's magnetosphere during the Voyager 1 encounter on days 317 and 318 in 1980 and the Voyager 2 encounter on days 237 and 238 in 1981, respectively. The rotating magnetosphere of Saturn is modeled by two-dimensional axisymmetric equilibrium solutions of the Grad-Shafranov type equation, which includes effects of the plasma pressure gradient force and the centrifugal force due to plasma toroidal rotation, by prescribing the radial profiles of plasma density and temperature in the equatorial plane. By varying the equatorial plasma profiles the equilibrium solutions are obtained with reasonably good fit to the observed plasma and magnetic field data along the orbits of the Voyager 1 encounter with the Saturn's magnetosphere on days 317 and 318 in 1980 and the Voyager 2 encounter on days 237 and 238 in 1981. The numerical equilibrium solutions provide detailed information of the global distribution of plasma environment and magnetic field structure of the Saturn's inner magnetosphere (for L < 24), and the results show that the plasma environment and the magnetic field configuration of the Saturn's magnetosphere are very different between these two spacecraft encounters with the Saturn. In particular, the meridian distributions of heavy ion density, azimuthal current density, and heavy ion beta have thin disk-like shapes centered at the equator for the Voyager 1 case, but have fat torus shapes for the Voyager 2 case. The difference results from the difference in the equatorial plasma pressure profile which decreases with R for R > 5RS for the Voyager 1 case, but is quite flat between R $\\simeq$ 5 and 17RS for the Voyager 2 case.

Chou, M.; Cheng, C. Z.

2010-08-01

207

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

208

Voyager Photometry of Saturn's A Ring  

Microsoft Academic Search

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

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

1993-01-01

209

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.

210

Voyager 2's encounter with Neptune  

NASA Technical Reports Server (NTRS)

The results of Voyager 2 observations of Neptune are reviewed. Observations of Neptune's Great Dark Spot, rotation atmosphere, magnetic field, rings, and satellites are discussed. Also, observations of Triton are considered, noting the presence of geyser activity on the satellite. Several photographs of features on both Neptune and Triton are presented.

Mclaughlin, William I.

1990-01-01

211

Voyager 2 at Neptune - Imaging science results  

Microsoft Academic Search

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

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

1989-01-01

212

Planetary radio astronomy observations from Voyager 2 near Jupiter  

NASA Technical Reports Server (NTRS)

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 identification of plasma wave emissions similar to those detected by Voyager 1, the plasma torus associated with Io appeared somewhat denser to Voyager 2 than it did to Voyager 1. The paper reports on quasi-periodic sinusoidal or impulsive bursts in the broadcast band range of wavelengths (800 to 1800 kHz). A Faraday effect appears at decametric frequencies, which probably results from propagation of the radiation near its sources on Jupiter. Finally, the occurrence of decametric emission in homologous arc families is discussed.

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

1979-01-01

213

Extraterrestrial environmental physics was very much in the news in January 2005 when the European Space Agency's Huygens probe touched down on  

E-print Network

the European Space Agency's Huygens probe touched down on the surface of Titan, the largest moon of Saturn. During its descent the probe measured Titan's atmosphere, including temperature, pressure, wind, aerosols back from Titan Images from the European Space Agency. More information on the Huygens mission

Williams, Paul

214

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

Microsoft Academic Search

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

Anh-quynh Nguyen; Kuniyasu Suzaki

2007-01-01

215

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.

216

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

NASA Astrophysics Data System (ADS)

Understanding General Relativity at all scales requires, in particular, understanding gravity at quantum level. To attempt this, tests of the most prominent aspect of General Relativity, the Einstein Equivalence Principle, can be performed with the next generation of atomic quantum sensors to significantly improved accuracy. To exploit the ultimate limits of atomic sensors a dedicated space platform is needed; the advantages space offers are, among others, unperturbed free-fall conditions, longer interaction times per measurement and large variations in velocity and gravitational field. In the frame of the third medium class launch opportunity of ESA's Cosmic Vision 2015 - 2025 programme a study was conducted - STE-QUEST (Space-Time Explorer and QUantum Equivalence principle Test), one of the candidates for a medium class mission - and the feasibility of such a mission assessed. The spacecraft would carry two instruments probing the different aspects of the Einstein Equivalence Principle: begin{enumerate} A dual species ( (87) Rb and (85) Rb) atom interferometer to probe the universality of propagation of matter waves. A high-performance time and frequency link dedicated to comparison of atomic clocks on ground. The specific primary science objectives for STE-QUEST are: begin{enumerate} Universality of propagation of matter waves test begin{itemize} Test of the universality of free fall of matter waves to an uncertainty of the Eötvös ratio lower than 2*10 (-15) . Gravitational redshift tests begin{itemize} Sun gravitational red-shift measurement to a fractional uncertainty of 2*10 (-6) , with an ultimate goal of 5*10 (-7) . Moon gravitational red-shift measurement to a fractional uncertainty of 4*10 (-4) , with an ultimate goal of 9*10 (-5) . Such a measurement has never been attempted before. The availability of an atomic clock on-board the spacecraft (optional) would additionally allow testing the Earth gravitational red-shift measurement to a fractional uncertainty of 2*10 (-7) . Assessment of the feasibility of reaching these target sensitivities through a space mission required extensive simulations and modeling. This involved determining and optimizing the orbit for such measurements by minimizing gravity gradients and non-gravitational disturbances (for both instruments), maximizing gravitational acceleration around perigee (for the interferometer measurements) and maximizing the common view with ground clocks and the variations of gravitational potential (for red-shift measurements). Numerical simulations have been performed where the computed measurement performance was fed back into the orbit optimization. In parallel, mission designs have been studied, to identify the drivers for accommodation on the spacecraft as well as for in-orbit operation and calibration. At the end of the study, viable mission designs have been established, fulfilling all science requirements and to the accuracy required. The flow-down starting from the science requirements and instrument needs to the mission definition will be presented, including details of spacecraft design and payload accommodation, in-orbit operations and instrument calibration aspects. Examples of trade-offs during the iterative process of maximizing the science return while optimizing the instrument and spacecraft design will be highlighted.

Heske, Astrid; Cacciapuoti, Luigi; Gehler, Martin

217

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

218

Spectrophotometric probe  

DOEpatents

A support structure bearing at least one probe for making spectrophotometric measurements of a fluid using a source of light and a spectrophotometer. The probe includes a housing with two optical fibers and a planoconvex lens. A sleeve bearing a mirror surrounds the housing. The lens is separated from the mirror by a fixed distance, defining an interior space for receiving a volume of the fluid sample. A plurality of throughholes extending through the sleeve communicate between the sample volume and the exterior of the probe, all but one hole bearing a screen. A protective jacket surrounds the probe. A hollow conduit bearing a tube is formed in the wall of the probe for venting any air in the interior space when fluid enters. The probe is held at an acute angle so the optic fibers carrying the light to and from the probe are not bent severely on emergence from the probe.

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

1994-01-01

219

New Access and Analysis Tools for Voyager LECP Data  

NASA Astrophysics Data System (ADS)

The Low Energy Charged Particle (LECP) instruments on the Voyager 1 and 2 spacecraft have been returning unique scientific measurements since launching in 1977, most notably observations from the historic tour of the giant planets. As these spacecraft continue on their exit trajectories from the Solar system they have become an interstellar mission and have begun to probe the boundary between the heliosphere and the interstellar cloud and continue to make exciting discoveries. As the mission changed from one focused on discrete encounters to an open ended search for heliospheric boundaries and transitory disturbances, the positions and timing of which are not known, the data processing needs have changed. Open data policies and the push to draw data under the umbrella of emerging Virtual Observatories have added a data sharing component that was not a part of the original mission plans. We present our work in utilizing new, reusable software analysis tools to access legacy data in a way that leverages pre-existing data analysis techniques. We took an existing Applied Physics Laboratory application, Mission Independent Data Layer (MIDL) -- developed originally under a NASA Applied Information Research Program (AISRP) and subsequently used with data from Geotail, Cassini, IMP-8, ACE, Messenger, and New Horizons -- and applied it to Voyager data. We use the MIDL codebase to automatically generate standard data products such as daily summary plots and associated tabulated data that increase our ability to monitor the heliospheric environment on a regular basis. These data products will be publicly available and updated automatically and can be analyzed by the community using the ultra portable MIDL software launched from the data distribution website. The currently available LECP data will also be described with SPASE metadata and incorporated into the emerging Virtual Energetic Particle Observatory (VEPO).

Brown, L. E.; Hill, M. E.; Decker, R. B.; Cooper, J. F.; Krimigis, S. M.; Vandegriff, J. D.

2008-12-01

220

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

E-print Network

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

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

2014-01-01

221

Voyager spacecraft images of Jupiter and Saturn  

Microsoft Academic Search

The Voyager imaging system is described, noting that it is made up of a narrow-angle and a wide-angle TV camera, each in turn consisting of optics, a filter wheel and shutter assembly, a vidicon tube, and an electronics subsystem. The narrow-angle camera has a focal length of 1500 mm; its field of view is 0.42 deg and its focal ratio

Morris M. Birnbaum

1982-01-01

222

Early Voyager 1 Images of Jupiter  

NASA Technical Reports Server (NTRS)

These Jupiter photographs are part of a set taken by Voyager 1 on December 10 and 11, 1978 from a distance of 83 million km (52 million miles) or more than half the distance from the Earth to the sun. At this range, Voyager 1 is able to record more detail on the giant planet than the very best ground-based telescopes. The highest resolution ever obtained on the Jovian disk was recorded by Pioneer 11 four years ago. Voyager, however, has longer focal-length optics than Pioneer, and while nearly three months from encounter ( March 1979) was able to achieve higher resolution than that obtained by Pioneer only 24 hours from its encounter on 3 December 1974.

Jupiter's colorful and turbulent atmosphere is evident in these photographs. The entire visible surface of the planet is made up of multiple layers of clouds, composed primarily of ammonia ice crystals colored by small amounts of materials of unknown composition. The Great Red Spot, seen to the lower left of 2 and lower right of 3, is now recovering from a period of relative inconspicuousness. An atmospheric system larger than the Earth and more than 100 years old, the Great Red Spot remains a mystery and a challenge to Voyager instruments. A bright convective cloud (center of and right of center in 4) displays a plume which has been swept westward (to the left) by local currents in the planet's equatorial wind system.

Below and to the left and right of the Great Red Spot are a pair of white oval clouds; a third can be seen in 1. All three were formed almost 40 years ago and are the second oldest class of discrete features identified in the Jovian atmosphere.

Each of the pictures was produced from blue, green, and orange originals in JPL's Image Processing Laboratory.

1978-01-01

223

Voyager observations of 1985U1  

NASA Technical Reports Server (NTRS)

Of the 10 small Uranian satellites, 1985U1 is the largest and the only one for which a resolved image was obtained by Voyager 2. In terms of albedo, the other nine satellites seem to be similar. Thus the single image of 1985U1 is important in suggesting what these other objects may be like. Size, shape, surface features, and photometry are examined.

Thomas, P.; Veverka, J.

1987-01-01

224

Fourier spectroscopy on planetary missions including Voyager  

NASA Technical Reports Server (NTRS)

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

Hanel, R. A.

1981-01-01

225

Voyager 2 plasma wave observations at Saturn  

Microsoft Academic Search

The first inbound Voyager 2 crossing of Saturn's bow shock (at 31.7 Saturn radii near local noon) and the last outbound crossing (at 87.4 Saturn radii near local dawn) had similar plasma wave signatures. However, many other aspects of the plasma wave measurements differed considerably during the inbound and outbound passes, suggesting the presence of effects associated with significant north-south

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

1982-01-01

226

Voyager 2 plasma wave observations at Uranus  

Microsoft Academic Search

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

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

1987-01-01

227

Spectrophotometry of Io - Preliminary Voyager 1 results  

Microsoft Academic Search

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

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

1980-01-01

228

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

229

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

230

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

231

Properties and dynamics of Jupiter's gossamer rings from Galileo, Voyager, Hubble and Keck images  

Microsoft Academic Search

We present a comprehensive examination of Jupiter's “gossamer” rings based on images from Voyager, Galileo, the Hubble Space Telescope and the W.M. Keck Telescope. We compare our results to the simple dynamical model of Burns et al. [Burns, J.A., Showalter, M.R., Hamilton, D.P., Nicholson, P.D., de Pater, I., Ockert-Bell, M., Thomas, P., 1999. Science 284, 1146–1150] in which dust is

Mark R. Showalter; Imke de Pater; Giuli Verbanac; Douglas P. Hamilton; Joseph A. Burns

2008-01-01

232

VOYAGER 2 - SPACECRAFT SHROUD IS MATED WITH TITAN CENTAUR LAUNCH VEHICLE  

NASA Technical Reports Server (NTRS)

The enshrouded Voyager spacecraft to be launched on a mission to the outer planets no earlier than August 20 was mated with Titan/Centaur-7 at Launch Complex 41 today. The 1,800-pound spacecraft is to conduct an extensive survey of Jupiter, Saturn, and perhaps, Uranus, on a mission which will carry it into galactic space. A sister spacecraft is scheduled for launch on a similar journey no earlier than September 1.

1977-01-01

233

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

234

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

Microsoft Academic Search

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

Raymond Zenick; Kimberly Kohlhepp; Russell Partch

2004-01-01

235

Probe measurements of the space potential in a radio frequency discharge  

NASA Astrophysics Data System (ADS)

The dc and radio frequency (rf) components (and harmonics) of the probe potential have been measured in the midplane of a 13.56-MHz parallel-plane rf discharge in argon over a wide range of discharge voltages and at gas pressures between 10 mTorr and 1.0 Torr. rf potential measurements were made with different input capacitances to determine the true magnitude of the rf plasma potential and the probe capacitance. For a symmetrically driven rf discharge, the rf plasma potential Vrf is mainly composed of the second harmonic of the driving voltage Vdr over a wide range of gas pressures. For high values of Vdr, Vrf ?0.1 Vdr while the dc probe potential Vdc is about 0.4 Vdr. These results are in good agreement with corresponding theoretical predictions found in the literature. For an asymmetrically driven rf discharge with equal electrode area, the rf plasma potential has an additional fundamental harmonic component equal to half the rf driving voltage. Values of rf plasma potential and probe capacitance given here allow us to specify the requirements on probe circuitry for different kinds of probe measurements in rf discharges.

Godyak, V. A.; Piejak, R. B.

1990-10-01

236

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

Microsoft Academic Search

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

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

2007-01-01

237

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

NASA Technical Reports Server (NTRS)

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

Roth, E. A.

1971-01-01

238

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

239

Energetic Particles at Voyager 1 in the Interstellar Medium and Voyager 2 in the Heliosheath  

NASA Astrophysics Data System (ADS)

Voyager 1 (at 128 AU, N35(°) lat. in mid-2014) evidently made a transition from the heliosheath into the local interstellar medium on or about doy 238 of 2012 at 121.6 AU. Prior to the doy 238 transition, Voyager 1 passed through two partial “depletion regions” during 2012 doys 210-215 and 226-234. In the depletion regions, intensities of charged particles of heliospheric origin (suprathermal ions, ACRs, low-energy electrons) decreased, while those of galactic origin (GCR ions and electrons) increased, and the magnetic field intensity increased but its direction remained close to that measured in the heliosheath. Low-energy helosheath electrons 26-70 keV begin decreasing ?2012.5, dropped sharply at the 1st GCR increase, made a weak recovery between 1st and 2nd GCR increase, and dropped to background levels after 2nd GCR increase. After 2012/238 the intensity decreases of protons 3-30 MeV showed pancake-like pitch-angle distributions. At Voyager 2 (at 105 AU, S31(°) lat.), which is still in the heliosheath, low-energy ions from at least 0.03 to 30 MeV showed increasing 1st order anisotropies during the period 2013.0-2013.3 that are directed in the +T direction, i.e., away from the heliosheath nose toward its flank from the perspective of Voyager 2 (at a longitude ?45(°) from the nose). Both the intensities and associated partial pressures of low-energy heliosheath ions had decreased at Voyager 2 since its termination shock crossing on 2007/242. Intensities of suprathermal ions ?100 keV, which dropped by a factor ?7 from the shock crossing to 2013.3, have since increased by a factor ?2, apparently in response to a transient disturbance that is also associated with the enhanced tangential streaming of energetic ions in the +T direction.

Decker, Robert; Roelof, Edmond; Krimigis, Stamatios; Hill, Matthew

240

Stories of initiation for the modern age: explorations of textual and theatrical fantasy in Jules Verne’s Voyage à travers l’impossible and Philip Pullman’s His Dark Materials   

E-print Network

While the theatrical works of Jules Verne have gathered some critical attention over recent years, the text of the Voyage à travers l’Impossible has remained an obscure space in the author’s oeuvre or deemed unworthy by ...

Theodoropoulou, Athanasia

2009-01-01

241

Spectrophotometry of Io - Preliminary Voyager 1 results  

NASA Technical Reports Server (NTRS)

Multispectral images of Io acquired with the Voyager 1 narrow-angle camera agree with earth-based spectrophotometry to better than 10%. Although the surface materials have general spectral properties similar to various allotropes of sulfur, their ultraviolet (UV) reflectances are much higher. It is likely that varying amounts of SO2 frost mixed with or absorbed on sulfur-rich materials raises the UV reflectance. The possible association with large amounts of SO2 with low temperature forms of sulfur in the white patches on Io is consistent with Io surface models in which SO2 and S exist in thermally stable stratified zones.

Soderblom, L.; Johnson, T.; Kupferman, P.; Pieri, D.; Morrison, D.; Danielson, E.; Smith, B.; Veverka, J.; Sagan, C.; Cook, A.

1980-01-01

242

Satellite ephemerides for the Voyager Neptune encounter  

NASA Technical Reports Server (NTRS)

This paper presents the results of the latest fits of both analytical theory and numerically integrated Neptunian satellite orbits to Earth-based astrometric observations. Ephemerides based on the integrated orbits will be used by the Voyager project for pre-encounter planning and analysis until late 1988 when the final pre-encounter ephemerides will be produced. As a by-product of the orbit fits, new estimates of the Neptune mass, the second zonal harmonic of Neptune, and the pole orientation of Neptune are obtained. The theory and integrated orbits are compared with each other and with orbits obtained by previous investigators.

Jacobson, Robert A.

1988-01-01

243

Satellite ephemerides for the Voyager Neptune encounter  

NASA Astrophysics Data System (ADS)

This paper presents the results of the latest fits of both analytical theory and numerically integrated Neptunian satellite orbits to Earth-based astrometric observations. Ephemerides based on the integrated orbits will be used by the Voyager project for pre-encounter planning and analysis until late 1988 when the final pre-encounter ephemerides will be produced. As a by-product of the orbit fits, new estimates of the Neptune mass, the second zonal harmonic of Neptune, and the pole orientation of Neptune are obtained. The theory and integrated orbits are compared with each other and with orbits obtained by previous investigators.

Jacobson, Robert A.

244

Sequencing Voyager II for the Uranus encounter  

NASA Technical Reports Server (NTRS)

The process of developing the programmed sequence of events necessary for the Voyager 2 spacecraft to return desired data from its Uranus encounter is discussed. The major steps in the sequence process are reviewed, and the elements of the Mission Sequence Software are described. The design phase and the implementation phase of the sequence process are discussed, and the Computer Command Subsystem architecture is examined in detail. The software's role in constructing the sequences and converting them into onboard programs is elucidated, and the problems unique to the Uranus encounter sequences are considered.

Morris, R. B.

1986-01-01

245

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.

246

Io plasma torus electrons - Voyager 1  

NASA Technical Reports Server (NTRS)

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

Sittler, E. C., Jr.; Strobel, Darrell F.

1987-01-01

247

Expedition on the Bay Virtual Voyage  

NSDL National Science Digital Library

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

Don Reed

248

Voyager 2 Uranus and Neptune targeting  

NASA Technical Reports Server (NTRS)

Targeting strategies are developed for the Voyager 2 flybys of Uranus and Neptune/Triton. The need to maximize science return, conserve propellant, and maintain spacecraft safety presents a challenge, given the difficulty in estimating the spacecraft orbit relative to these outer planets. Expected propellant usage, science return, and targeting complexity are presented for each targeting strategy. For the dual encounter of Neptune and its satellite Triton, split targeting conditions are proposed to fix the most important conditions at each body, and thus minimize science losses resulting from Triton ephemeris uncertainties.

Gray, D. L.; Cesarone, R. J.; Van Allen, R. E.

1982-01-01

249

Voyager imaging of Triton's clouds and hazes  

NASA Technical Reports Server (NTRS)

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

Rages, Kathy; Pollack, James B.

1992-01-01

250

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

251

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

252

Meteorological Implications of the First Voyage of Christopher Columbus  

Microsoft Academic Search

The log of the first voyage of Christopher Columbus to the New World provides valuable information on the meteorological conditions of September 1492. Comparison and analysis of the descriptive accounts of weather made by Columbus and his pilots to other available Columbian and modern data leads to two distinct perspectives on the Columbian voyage: an examination of the frequency of

Randall S. Cerveny; Jay S. Hobgood

1992-01-01

253

Plasma observations near Neptune - Initial results from Voyager 2  

Microsoft Academic Search

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

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

1989-01-01

254

The near real time image navigation of pictures returned by Voyager 2 at Neptune  

NASA Technical Reports Server (NTRS)

The development of a process for performing image navigation in near real time is described. The process was used to accurately determine the camera pointing for pictures returned by the Voyager 2 spacecraft at Neptune Encounter. Image navigation improves knowledge of the pointing of an imaging instrument at a particular epoch by correlating the spacecraft-relative locations of target bodies in inertial space with the locations of their images in a picture taken at that epoch. More than 8,500 pictures returned by Voyager 2 at Neptune were processed in near real time. The results were used in several applications, including improving pointing knowledge for nonimaging instruments ('C-smithing'), making 'Neptune, the Movie', and providing immediate access to geometrical quantities similar to those traditionally supplied in the Supplementary Experiment Data Record.

Underwood, Ian M.; Bachman, Nathaniel J.; Taber, William L.; Wang, Tseng-Chan; Acton, Charles H.

1990-01-01

255

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

256

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

Microsoft Academic Search

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

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

1977-01-01

257

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

258

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

ERIC Educational Resources Information Center

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

Range, Shannon K'doah; Mullins, Jennifer

259

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

260

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

261

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

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

262

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

263

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

SciTech Connect

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

Hallock, G.A.

1983-04-11

264

Ultra high energy photons as probes of Lorentz symmetry violations in stringy space-time foam models  

E-print Network

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

Luca Maccione; Stefano Liberati; Guenter Sigl

2010-06-08

265

A new Langmuir probe concept for rapid sampling of space plasma electron density  

NASA Astrophysics Data System (ADS)

In this paper we describe a new Langmuir probe concept that was invented for the in situ investigation of HF radar backscatter irregularities, with the capability to measure absolute electron density at a resolution sufficient to resolve the finest conceivable structure in an ionospheric plasma. The instrument consists of two or more fixed-bias cylindrical Langmuir probes whose radius is small compared to the Debye length. With this configuration, it is possible to acquire absolute electron density measurements independent of electron temperature and rocket/satellite potential. The system was flown on the ICI-2 sounding rocket to investigate the plasma irregularities which cause HF backscatter. It had a sampling rate of more than 5 kHz and successfully measured structures down to the scale of one electron gyro radius. The system can easily be adapted for any ionospheric rocket or satellite, and provides high-quality measurements of electron density at any desired resolution.

Jacobsen, K. S.; Pedersen, A.; Moen, J. I.; Bekkeng, T. A.

2010-08-01

266

Study of sensor positioning in the space for probe abdominal echographics  

Microsoft Academic Search

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

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

1996-01-01

267

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

268

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

269

Investigating the Spectral Evolution of Anomalous Cosmic Rays at Voyager 1  

NASA Astrophysics Data System (ADS)

Anomalous cosmic rays (ACRs) were thought to be accelerated at the solar wind termination shock by the diffusive shock acceleration process. When Voyager 1 crossed the termination shock in 2004, the measured ACR spectra did not match the theoretical prediction of a continuous power law, and the source of the high-energy ACRs was not observed. Then, ACR spectra started to unfold in the heliosheath during the declining phase of the solar cycle 23. In this work, a three-dimensional magnetohydrodynamic background model with constant solar wind boundary conditions is applied to Helium and Oxygen ACRs. Further, we use a backward-in-time stochastic integration technique where phase-space trajectories are integrated until 0.5 MeV/n is reached. Solar activity effects can be simulated using changes in drifts and diffusion. We will use changes in heliospheric current sheet tilt angle and diffusion coefficient to investigate the spectral evolution of ACRs at Voyager 1. Our results will be compared with the Voyager 1 observations.

Senanayake, Udara; Cummings, A. C.; Stone, E. C.; Florinski, Vladimir

270

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

271

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.

272

Color Voyager 2 Image Showing Crescent Uranus  

NASA Technical Reports Server (NTRS)

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

1990-01-01

273

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.

274

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

275

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

276

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

PubMed

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

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

1999-12-01

277

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

NASA Technical Reports Server (NTRS)

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

Carpenter, Paul; Armstrong, John

2004-01-01

278

On Determining Wood Thermal Diffusivity and Probe Spacing for Sap Flow Measurements using In-Situ Heat Response Curves  

NASA Astrophysics Data System (ADS)

The heat pulse method is widely used to measure water flux in plants and soil; it works by inferring the velocity of water in a porous medium from the speed at which a heat pulse is propagated through the system. No systematic, non-destructive calibration procedure exists to determine the site-specific parameters necessary for calculating sap velocity: wood thermal diffusivity and probe spacing. Such parameter calibration is crucial to obtaining the correct transpiration amount from the sap flow measurements at the plant scale and consequently to the up-scaling of water flux to a larger scale and to the water cycle modeling along the soil-vegetation-atmosphere continuum. The purpose of this study is to present a statistical framework to simultaneously estimate these parameters from in-situ heat response curves collected by the implanted probes of heat ratio apparatus. Conditioned on the heat response data, the parameters are inferred using a Bayesian inversion technique with Markov chain Monte Carlo sampling method. The primary advantage of the proposed methodology is that, unlike most of the existing work, it does not require known probe spacing or any further intrusive sampling of sapwood. The Bayesian framework also enables direct quantification of uncertainty in estimated sap flow velocity. Experiments using synthetic data show that multiple tests on the same apparatus are essential to obtain reliable, accurate solutions. When applied to field conditions, these tests are conducted during different seasons and automated using the existing data logging system. The seasonality of wood thermal diffusivity is obtained as a by-product of the parameter estimation process, and it shows consistency with the seasonal change of tree diameters monitored using tree dendrometer. An empirical factor is adopted to account for flow deformation caused by the implanted probes, and it is also estimated in this study. The proposed methodology is ready to be applied to calibrate existing heat ratio sap flow systems at other sites. It is especially useful when alternative transpiration calibration device such as lysimeter is not available.

Chen, X.; Miller, G.; Baldocchi, D.; Rubin, Y.

2008-12-01

279

The Galilean satellites and Jupiter - Voyager 2 imaging science results  

NASA Technical Reports Server (NTRS)

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 can be obtained from earth-based studies. The present report briefly describes the changes in the cloud morphologies and local atmospheric motions. 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 reveals a system of overlapping bright and dark linear features. Ganymede exhibits 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.

Smith, B. A.; Soderblom, L. A.; Beebe, R.; Boyce, J.; Briggs, G.; Carr, M.; Collins, S. A.; Johnson, T. V.; Cook, A. F., II; Danielson, G. E.; Morrison, D.

1979-01-01

280

Voyager 1 Explores the "Magnetic Highway" - Duration: 0:47.  

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...

281

Dynamic feature analysis for Voyager at the Image Processing Laboratory  

NASA Technical Reports Server (NTRS)

Voyager 1 and 2 were launched from Cape Kennedy to Jupiter, Saturn, and beyond on September 5, 1977 and August 20, 1977. The role of the Image Processing Laboratory is to provide the Voyager Imaging Team with the necessary support to identify atmospheric features (tiepoints) for Jupiter and Saturn data, and to analyze and display them in a suitable form. This support includes the software needed to acquire and store tiepoints, the hardware needed to interactively display images and tiepoints, and the general image processing environment necessary for decalibration and enhancement of the input images. The objective is an understanding of global circulation in the atmospheres of Jupiter and Saturn. Attention is given to the Voyager imaging subsystem, the Voyager imaging science objectives, hardware, software, display monitors, a dynamic feature study, decalibration, navigation, and data base.

Yagi, G. M.; Lorre, J. J.; Jepsen, P. L.

1978-01-01

282

Gamma ray burst delay times probe the geometry of momentum space  

E-print Network

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

Laurent Freidel; Lee Smolin

2011-03-29

283

The Voyager Spacecraft. [Jupiter-Saturn mission investigations  

NASA Technical Reports Server (NTRS)

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

1979-01-01

284

Triton and Nereid astrographic observations from Voyager 2  

NASA Technical Reports Server (NTRS)

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

Jacobson, R. A.

1991-01-01

285

Standing Alfven wave current system at Io - Voyager 1 observations  

NASA Technical Reports Server (NTRS)

The enigmatic control of the occurrence frequency of Jupiter's decametric emissions by the satellite Io has been explained theoretically on the basis of its strong electrodynamic interaction with the corotating Jovian magnetosphere leading to field-aligned currents connecting Io with the Jovian ionosphere. Direct measurements of the perturbation magnetic fields due to this current system were obtained by the Goddard Space Flight Center magnetic field experiment on Voyager 1 on March 5, 1979, when it passed within 20,500 km south of Io. An interpretation in the framework of Alfven waves radiated by Io leads to current estimates of 2.8 x 10 to the 6th A. A mass density of 7400-13,600 proton mass units/cu cm is derived, which compares very favorably with independent observations of the torus composition characterized by 7-9 proton mass units per electron for a local electron density of 1050-1500/cu cm. The power dissipated in the current system may be important for heating the Io heavy ion torus, inner magnetosphere, Jovian ionosphere, and possibly the ionosphere or even the interior of Io.

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

1981-01-01

286

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

E-print Network

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

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

2014-11-12

287

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

NASA Technical Reports Server (NTRS)

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

Posner, Jack (Editor)

1961-01-01

288

Two-dimensional fringe probing of transient liquid temperatures in a mini space.  

PubMed

A 2D fringe probing transient temperature measurement technique based on photothermal deflection theory was developed. It utilizes material's refractive index dependence on temperature gradient to obtain temperature information from laser deflection. Instead of single beam, this method applies multiple laser beams to obtain 2D temperature information. The laser fringe was generated with a Mach-Zehnder interferometer. A transient heating experiment was conducted using an electric wire to demonstrate this technique. Temperature field around a heating wire and variation with time was obtained utilizing the scattering fringe patterns. This technique provides non-invasive 2D temperature measurements with spatial and temporal resolutions of 3.5 ?m and 4 ms, respectively. It is possible to achieve temporal resolution to 500 ?s utilizing the existing high speed camera. PMID:21639535

Xue, Zhenlan; Qiu, Huihe

2011-05-01

289

Reciprocal space XRD mapping with varied incident angle as a probe of structure variation within surface depth  

SciTech Connect

In this study, we used a differential-depth X-Ray diffraction Reciprocal Spacing Mapping (XRD RSM) technique to investigate the crystal quality of a variety of SRF-relevant Nb film and bulk materials. By choosing different X-ray probing depths, the RSM study successfully revealed evolution the of materials? microstructure after different materials processes, such as energetic condensation or surface polishing. The RSM data clearly measured the materials? crystal quality at different thickness. Through a novel differential-depth RSM technique, this study found: I. for a heteroepitaxy Nb film Nb(100)/MgO(100), the film thickening process, via a cathodic arc-discharge Nb ion deposition, created a near-perfect single crystal Nb on the surface?s top-layer; II. for a mechanically polished single-crystal bulk Nb material, the microstructure on the top surface layer is more disordered than that in-grain.

Yang, Qiguang [Norfolk State University; Williams, Frances [Norfolk State University; Zhao, Xin [JLAB; Reece, Charles E. [JLAB; Krishnan, Mahadevan [AASC, San Leandro, California

2013-09-01

290

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

PubMed

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

Crawford, Ian A

2010-10-01

291

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

Microsoft Academic Search

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

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

1967-01-01

292

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

E-print Network

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

Giovanni Amelino-Camelia; Tsvi Piran

2000-06-19

293

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

Microsoft Academic Search

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

M. Henrist; R. Duysinx; A. Monfils

1974-01-01

294

Probing the interstellar medium in early-type galaxies with Infrared Space Oberservatory observations  

NASA Technical Reports Server (NTRS)

Four IRAS-detected early-type galaxies were observed with the Infrared Space Observatory (ISO). With the exception of the 15 mu m image of NGC 1052, the mid-IR images of NGC 1052, NGC 1155, NGC 5866, and NGC 6958 at 4.5, 7, and 15 mu m show extended emission.

Malhotra, S.; Hollenbach, D.; Helou, D.; Silbermann, N.; Valjavec, E.; Rubin, R.; Dale, D.; Hunter, D.; Lu, N.; Lord, S.; Dinerstein, H.; Thronson, H.

2000-01-01

295

PROBING THE VALUE SPACE: AN EMPIRICAL STUDY OF PERSONAL VALUE SYSTEM OF INDIAN SCIENTISTS  

Microsoft Academic Search

The present study attempts to examine the value system of scientists working in a research and development (R&D) laboratory functioning under the Council of Scientific and Industrial Research (CSIR), India, a public -funded research organization system. The focus of the study is on, first, the examination of selected items that are viewed as high\\/low in importance in the value space

Santanu Roy; Sunil K. Dhawan

296

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

NSDL National Science Digital Library

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

297

Active probing of space plasmas. Final report, 25 October 1985-30 September 1989  

SciTech Connect

During the course of the research period our efforts were focused on the following areas: (1) An examination of stochastic acceleration mechanisms in the ionosphere; (2) A study of nonequilibrium dynamics of the coupled magnetosphere - ionosphere system; and (3) Laboratory studies of active space experiments. Reprints include: Dynamics of charged particles in the near wake of a very negatively charged body -- Laboratory experiment and numerical simulation; Laboratory study of the electron temperature in the near wake of a conducting body; New model for auroral breakup during substorms; Substorm breakup on closed field lines; New model for substorm on sets -- The pre-breakup and triggering regimes; Model of the westward traveling surge and the generation of Pi 2 pulsations; Ionospheric electron acceleration by electromagnetic waves near regions of plasma resonances; Relativistic particle acceleration by obliquely propagating electromagnetic fields; Some consequences of intense electromagnetic wave injection into space plasmas.

Chan, C.; Silevitch, M.B.; Villalon, E.

1989-09-01

298

Probing the Activity Modification Space of the Cysteine Peptidase Cathepsin K with Novel Allosteric Modifiers  

PubMed Central

Targeting allosteric sites is gaining increasing recognition as a strategy for modulating the activity of enzymes, especially in drug design. Here we investigate the mechanisms of allosteric regulation of cathepsin K as a representative of cysteine cathepsins and a promising drug target for the treatment of osteoporosis. Eight novel modifiers are identified by computational targeting of predicted allosteric sites on the surface of the enzyme. All act via hyperbolic kinetic mechanisms in presence of low molecular mass substrates, as expected for allosteric effectors. Two compounds have sizable effects on enzyme activity using interstitial collagen as a natural substrate of cathepsin K and four compounds show a significantly stabilizing effect on cathepsin K. The concept of activity modification space is introduced to obtain a global perspective of the effects elicited by the modifiers. Analysis of the activity modification space reveals that the activity of cathepsin K is regulated via multiple, different allosteric mechanisms. PMID:25184245

Novinec, Marko; Lenar?i?, Brigita; Baici, Antonio

2014-01-01

299

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

Microsoft Academic Search

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

Varun Sahni; Yuri Shtanov

2008-01-01

300

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

301

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

302

Plasma electron analysis: Voyager plasma science experiment  

NASA Technical Reports Server (NTRS)

The Plasma Science Experiment (PLS) on the Voyager spacecraft provide data on the plasma ions and electrons in the interplanetary medium and the magnetospheres of the giant planets Jupiter and Saturn. A description of the analysis used to obtain electron parameters (density, temperature, etc.) from the plasma science experiment PLS electron measurements which cover the energy range from 10 eV to 5950 eV is presented. The electron sensor (D cup) and its transmission characteristics are described. A derivation of the fundamental analytical expression of the reduced distribution function F(e) is given. The electron distribution function F(e), used in the moment integrations, can be derived from F(e). Positive ions produce a correction current (ion feedthrough) to the measured electron current, which can be important to the measurements of the suprathermal electron component. In the case of Saturn, this correction current, which can either add to or subtract from the measured electron current, is less than 20% of the measured signal at all times. Comments about the corrections introduced by spacecraft charging to the Saturn encounter data, which can be important in regions of high density and shadow when the spacecraft can become negatively charged are introduced.

Sittler, E. C., Jr.

1983-01-01

303

Voyager spacecraft images of Jupiter and Saturn  

NASA Technical Reports Server (NTRS)

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

Birnbaum, M. M.

1982-01-01

304

New Voyager radio spectrograms of Uranus  

NASA Technical Reports Server (NTRS)

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

Calvert, W.; Tsintikidis, D.

1990-01-01

305

1958 NASA/USAF Space Probes (Able-1). Volume 1; Summary  

NASA Technical Reports Server (NTRS)

Early in calendar year 1958 Space Technology Laboratories, Inc. (STL) (then Space Technology Laboratories, a division of the Ramo-Wooldridge Corp.) developed for the Air Force Ballistic Missile Division (AFBMD) an Advanced Re-entry Test Vehicle (ARTV) for the purpose of testing ballistic missile nose cones at the full range of 5500 nautical miles. The two-stage ARTV utilized the Thor ballistic missile and the second stage propulsion system developed for the Vanguard program. In late 1957 and early 1958, STL/AFBMD prepared studies of various missile combinations which could be utilized for space testing. The Thor, in combination with the Vanguard second and third stages, was one of the vehicles considered which offered a very early capability of placing a reasonable payload in a lunar orbit. These STL/AFBMD studies were presented to various appropriate groups including the Killian, Millikan, H. J . Stewart Committees; Headquarters, Air Research and Development Command, and ARDC Centers. Subsequently the Advanced Research Projects Agency (ARPA) contacted STL relative to the availability of hardware for an early lunar shot. By utilizing existing spares already purchased for the ARTV, and by making use of the ARTV contractors already in being, it appeared feasible to launch by the third quarter of calendar year 1958 a payload which would be captured by the moon's gravitational force. On 27 March 1958, ARPA directed STL to proceed with a program of three lunar shots. As much as possible, these shots were to utilize existing ARTV spare hardware and impose no interference with the ballistic missile programs. In September this program was transferred to the direction of the National Aeronautics and Space Administration (NASA). On 17 August 1958 the first launching of the Able-1 vehicle was attempted, but the flight was terminated by a propulsion failure of the first stage. Subsequent launchings were attempted on 13 October and 8 November 1958. Of these launchirigs the October attempt was the most successful. Although the payload did not reach the vicinity of the moon, a maximum altitude of 71,700 was attained, and useful scientific data was obtained from the instrumentation.

1959-01-01

306

Is the Natario warp drive a valid candidate for an interstellar voyage to the star system Gliese 667C(GJ 667C)??  

E-print Network

an interstellar space travel to a "nearby" star at 22 light-years away with 3 potential habitable exo happen in a real interstellar travel from Earth to Gliese 667C and Horizons(causally disconnectedIs the Natario warp drive a valid candidate for an interstellar voyage to the star system Gliese

Boyer, Edmond

307

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

PubMed

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

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

2012-02-01

308

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

Microsoft Academic Search

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

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

2009-01-01

309

16 Engineering & Science/Summer 1989 The Voyager space-  

E-print Network

alignment occurs among them. During this short-lived alignment a prop- erly designed spacecraft launched's gravitational pull and fly on to Saturn, Uranus, and Neptune-the Grand Tour-and then, past Neptune, disappear Aug. 19_81_--_L ~~ Uranus LJM.1900 ~ Neptune r?~ During this short-lived alignment a properly de

Faraon, Andrei

310

The influence of collisions in the space-charge sheath on the ion current collected by a langmuir probe  

Microsoft Academic Search

The current\\/voltage characteristics of a cylindrical Langmuir probe have been studied in Ar+\\/electron afterglow plasmas in helium carrier gas under truly thermal conditions at 300 K using our flowing afterglow\\/Langmuir probe (FALP) apparatus. The orbital motion limited (oml) ion and electron current regions of the probe characteristics have been explored over a wide range of the reduced probe voltage (up

P. Špan?l; D. Smith; O. Chudacek; P. Kudrna; M. Tichy

1995-01-01

311

Jupiter's Stratospheric Hydrocarbons: From Voyager to Cassini  

NASA Astrophysics Data System (ADS)

Photolysis of methane gas in Jupiter's atmosphere by solar UV creates short-lived radical species, which subsequently recombine to form stable higher-mass hydrocarbons including acetylene (C2H2) and ethane (C2H6). With dramatically different photochemical lifetimes (3x107 s and 3x1010 s respectively at 5 mbar), these gases may be used as tracers of atmospheric circulation. For example, while ethane's lifetime greatly exceeds the predicted dynamical timescale for meridional mixing inferred from comet SL-9 debris (5-50 x108 s), the lifetime of acetylene is much less, and therefore different latitude distributions of these species are expected. In a recent paper (Nixon et al. 2007), infrared spectra acquired by the Cassini CIRS instrument during the Jupiter encounter of December 2000 were modeled to recover the meridional variations of both gases in the stratosphere (5 mbar) and upper troposphere (200 mbar). In this work, we have applied the same analysis to spectra acquired by Voyager IRIS 21 years earlier (1.75 Jupiter years), recovering the stratospheric variation. Some striking similarities and differences are evident: while the acetylene distribution in 1979 does not show the strong North-South hemispheric asymmetry seen in 2000, ethane on the other hand shows qualitatively a similar picture in the two epochs. In this presentation we show the meridional abundance variations from both of these important spacecraft datasets and discuss how the interplay of photochemistry and dynamics may explain the results. We also discuss how these findings relate to the current understanding of Jupiter's atmosphere, and suggest directions of future research. We acknowledge the support of the Cassini-Huygens Project and NASA Grant 07-OPR07-0048. References: C. A. Nixon et al., Icarus, 188, pp. 47-71, 2007.

Nixon, Conor A.; Achterberg, R. K.; Allen, M.; Maguire, W. C.; Flasar, F. M.; Teanby, N. A.; Irwin, P. G. J.

2009-09-01

312

Energetic Particle Measurements from Voyager 1 in the Heliosheath Depletion Region and Voyager 2 in the Heliosheath  

NASA Astrophysics Data System (ADS)

Voyager 1 (now at 125 AU, N35 deg. lat.) has been in the heliosheath depletion region since August 2012 while Voyager 2 (now at 101 AU, S30 deg. lat.) remains in the heliosheath proper. Measurements from the Voyager 1 LECP instrument taken in the depletion region are reviewed by S. M. Krimigis (this session). In the depletion region the intensities of charged particles of evidently heliospheric origin (suprathermal ions, ACRs, low-energy electrons) decreased while those of galactic origin (GCR ions and electrons) increased, and the magnetic field intensity increased but its direction remained close to that measured in the heliosheath. Entry into the main depletion region (> 2012 doy 238) was preceded by passage through two partial depletion regions during 2012 doy 210-215 and 2012 doy 226-234. In this presentation we discuss the evolution of angular distributions of energetic ions and protons measured at Voyager 1 from mid-2012 onward. We also discuss the variations of ion and electron intensities and angular distributions measured at Voyager 2 during the same period.

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

2013-12-01

313

Solar wind propagation from Ulysses to Voyager 2  

NASA Astrophysics Data System (ADS)

Ulysses near 5 AU and Voyager 2 near 80 AU were at the same heliolatitude in mid-2005. This alignment provides an opportunity to study the propagation of the solar wind through the heliosphere. Voyager 2 saw a large shock at roughly the time the solar wind from the alignment time was expected to arrive at Voyager 2 from Ulysses. We model two possible sources of this shock, fast streams from polar coronal holes and coronal mass ejections (CMEs), and obtain a reasonable match to the V2 data by combining these sources. We also investigate the slowdown of the solar wind due to pickup ions over this distance. The modeling of the shock allows us to remove the period when transient plasma from CMEs is important and determine that the solar wind speed decreases about 70 km/s due to pickup ions, consistent with a interstellar hydrogen density at the termination shock of about 0.09/cc.

Richardson, J.; Ying, L.; Wang, C.; McComas, D.

2006-12-01

314

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

315

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

316

Dust Impacts In the Outer Solar System Detected by Voyagers 1 and 2  

NASA Astrophysics Data System (ADS)

The plasma wave instruments (PWS) on the Voyager 1 and 2 spacecraft, which are currently at about 119 and 97 AU, have been consistently detecting a low rate of dust impacts as the spacecraft proceed outward from the Sun into interstellar space. Because of the high radial velocity of the spacecraft, ~ 17 and 15 km/sec, when a dust particle strikes the spacecraft it is almost instantly vaporized and ionized, thereby producing a rapidly expanding cloud of plasma that causes a voltage pulse in the PWS electric antenna. The voltage pulse has a very rapid rise time of about 10 ?s and is an easily identifiable waveform in the wideband electric field data. Due to a failure in the Voyager 2 waveform receiver no impact data are available from Voyager 2 beyond about 60 AU. However, the Voyager 1 waveform receiver is still working. Because of the very high data rates involved, 115.2 kb/s, antenna voltage waveforms can only be recorded for less than a minute per week, so the effective observing time is very small. Nonetheless, once the regions around the outer planets are excluded, a consistent background impact rate of a few impacts per hour is observed by both spacecraft. The impact rate appears to be increasing slightly with increasing radial distance, from about 3 ± 1 impacts per hour at 30 AU, to 6 ± 4 impacts per hour at 110 AU. If the impact cross-section of the spacecraft is assumed to be determined by the spacecraft high gain antenna, which has an area of 10.75 square meters, the corresponding particle flux varies from about 0.75 x 10-14 m-2 s-1 at 30 AU, to about 1.5 x 10-14 m-2 s-1 at 110 AU. Although we have no reliable method of estimating the size or origin of the particles, we note that this flux is consistent with the flux of submicron particles (10-15 to 10-9 g) arriving from interstellar space as detected by the Ulysses spacecraft at radial distances inside of 5 AU. Therefore, we believe that the particles are probably of interstellar origin.

Gurnett, D. A.; Persoon, A. M.; Granroth, L. J.; Kurth, W. S.

2011-12-01

317

Nanopore-Based DNA-Probe Sequence-Evolution Method Unveiling Characteristics of Protein-DNA Binding Phenomena in a Nanoscale Confined Space.  

PubMed

Almost all of the important functions of DNA are realized by proteins which interact with specific DNA, which actually happens in a limited space. However, most of the studies about the protein-DNA binding are in an unconfined space. Here, we propose a new method, nanopore-based DNA-probe sequence-evolution (NDPSE), which includes up to 6 different DNA-probe systems successively designed in a nanoscale confined space which unveil the more realistic characteristics of protein-DNA binding phenomena. There are several features; for example, first, the edge-hindrance and core-hindrance contribute differently for the binding events, and second, there is an equilibrium between protein-DNA binding and DNA-DNA hybridization. PMID:25751160

Liu, Nannan; Yang, Zekun; Lou, Xiaoding; Wei, Benmei; Zhang, Juntao; Gao, Pengcheng; Hou, Ruizuo; Xia, Fan

2015-04-01

318

Performance model of the Argonne Voyager multimedia server  

SciTech Connect

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

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

1997-07-01

319

Probing Cosmic Star Formation Using Long Gamma-Ray Bursts: New Constraints from the Spitzer Space Telescope  

NASA Astrophysics Data System (ADS)

We report on IRAC 4.5 ?m, IRAC 8.0 ?m, and MIPS 24 ?m deep observations of 16 gamma-ray burst (GRB) host galaxies performed with the Spitzer Space Telescope, and we investigate in the thermal infrared the presence of evolved stellar populations and dust-enshrouded star-forming activity associated with these objects. Our sample is derived from GRBs that were identified with subarcsecond localization between 1997 and 2001, and only a very small fraction (~20%) of the targeted sources are detected down to f4.5?m~3.5 ?Jy and f24?m~85 ?Jy (3 ?). This likely argues against a population dominated by massive and strongly starbursting (i.e., SFR>~100 Msolar yr-1) galaxies as has been recently suggested from submillimeter/radio and optical studies of similarly selected GRB hosts. Furthermore, we find evidence that some GRBs do not occur in the most infrared luminous regions-hence the most actively star-forming environments-of their host galaxies. Should the GRB hosts be representative of all star-forming galaxies at high redshift, models of infrared galaxy evolution indicate that >~50% of GRB hosts should have f24?m>~100 ?Jy. Unless the identification of GRBs prior to 2001 was prone to strong selection effects biasing our sample against dusty galaxies, we infer in this context that the GRBs identified with the current techniques cannot be directly used as unbiased probes of the global and integrated star formation history of the universe. Based on observations made with the Spitzer Space Telescope, operated by the Jet Propulsion Laboratory under NASA contract 1407.

Le Floc'h, Emeric; Charmandaris, Vassilis; Forrest, William J.; Mirabel, I. Félix; Armus, Lee; Devost, Daniel

2006-05-01

320

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

321

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

322

Titan interaction with Saturn's magnetosphere: Voyager 1 results revisited  

Microsoft Academic Search

We investigate the details of Titan's interaction with Saturn's magnetosphere, which includes formation and location of an ionopause, mass loading via ion pickup, and the effects of finite gyroradii. We present new interpretations of the Voyager 1 plasma instrument measurements not addressed by Hartle et al. (1982). Pickup ions H+ and H2+ dominate in the outermost region with respect to

E. C. Sittler; R. E. Hartle; A. F. Viñas; R. E. Johnson; H. T. Smith; I. Mueller-Wodarg

2005-01-01

323

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

324

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

325

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

326

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

327

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

328

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

329

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

330

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

331

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

332

Massively parallel visualization on linux clusters with Rocketeer Voyager  

Microsoft Academic Search

This paper describes Rocketeer Voyager, a versatile 3-D scientific visualization tool which processes in parallel a series of HDF output dumps from a large scale simulation. Rocketeer reads data defined on many types of grids and displays translucent surfaces and isosurfaces, vectors as glyphs, surface and 3-D meshes, etc. An interactive version is first used to view a few snapshots,

Robert A. Fiedler; John C. Norris

333

Recent Particle Measurements from Voyagers 1 and 2  

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

334

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

335

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

336

Voyager Interactive Web Interface to EarthScope  

Microsoft Academic Search

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

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

2004-01-01

337

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

338

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

339

Plasma waves near Saturn - Initial results from Voyager 1  

Microsoft Academic Search

The Voyager 1 plasma wave instrument detected many familiar types of plasma waves during the encounter with Saturn, including ion-acoustic waves and electron plasma oscillations upstream of the bow shock, an intense burst of electrostatic noise at the shock, and chorus, hiss, electrostatic electron cyclotron waves, and upper hybrid resonance emissions in the inner magnetosphere. A clocklike Saturn rotational control

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

1981-01-01

340

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

341

Titan interaction with Saturn's magnetosphere: Voyager 1 results revisited  

E-print Network

Titan interaction with Saturn's magnetosphere: Voyager 1 results revisited E. C. Sittler Jr., R. E March 2005; published 10 September 2005. [1] We investigate the details of Titan's interaction in the outermost region with respect to Titan's ``ionopause,'' followed by CH4 + at intermediate distances and N2

Johnson, Robert E.

342

Voyager 1 and 2 Atlas of Six Saturnian Satellites  

NASA Technical Reports Server (NTRS)

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

Batson, R. M.

1984-01-01

343

Overview of the Voyager ultraviolet spectrometry results through Jupiter encounter  

NASA Technical Reports Server (NTRS)

The observations of a number of objects by the Voyager EUV instruments are summarized. The summary is considered to demonstrate the wide ranging application of the EUV spectroscopy. It also marks an important step forward in spectrography and emphasizes the continuing importance of the search and discovery nature of spectroscopic techniques.

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

1981-01-01

344

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

345

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

346

The Voyager 2 Encounter with the Uranian System.  

ERIC Educational Resources Information Center

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

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

1986-01-01

347

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

ERIC Educational Resources Information Center

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

Crosby, Alfred W.; Nader, Helen

348

The Ocean Voyager II: an AUV designed for coastal oceanography  

Microsoft Academic Search

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

Samuel M. Smith; Stanley E. Dunn

1994-01-01

349

Voyager radio science observations of Neptune and triton  

Microsoft Academic Search

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

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

1989-01-01

350

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. PMID:21584986

Foxhall, Katherine

2012-01-01

351

Meteorological Implications of the First Voyage of Christopher Columbus.  

NASA Astrophysics Data System (ADS)

The log of the first voyage of Christopher Columbus to the New World provides valuable information on the meteorological conditions of September 1492. Comparison and analysis of the descriptive accounts of weather made by Columbus and his pilots to other available Columbian and modern data leads to two distinct perspectives on the Columbian voyage: an examination of the frequency of "calm" events, and an analysis of the lack of tropical storm activity. The major conclusions of the first portion of the study include: 1) The Columbian pilots' descriptions of "cairns" related to travel slower than travel occurring during other portions of the voyage. That rate of travel compares favorably to calm winds and an oceanic current of 0.4 knots, a value close to modern-day values; 2) The frequency of "calm" events experienced by Christopher Columbus in 1492 is significantly higher than the most liberal estimates of calms in the North Atlantic over the last 100 years; and 3) The locations of the Columbian calms are generally in the same region currently experiencing the highest frequency of calms. The main finding of the second portion of the study is that, based on historical hurricane records from 1886 to 1989, the center of a hurricane would have passed within 100 km of Columbus only once in the past 104 years. Inclusion of tropical storms increases this number to four out of 104 years. Therefore, while Columbus may indeed have been fortunate to have avoided severe weather during his voyage, the odds decidedly were in his favor. This Columbian "weather luck" was due to a combination of 1) encountering abnormally strong anticyclonic flow over the eastern North Atlantic, 2) starting late enough in the hurricane season to significantly decrease the probability of experiencing a hurricane, and 3) taking a north and easterly voyage, thereby avoiding the area of maximum hurricane occurrence.

Cerveny, Randall S.; Hobgood, Jay S.

1992-02-01

352

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

Microsoft Academic Search

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

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

1981-01-01

353

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

Microsoft Academic Search

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

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

1979-01-01

354

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

NASA Technical Reports Server (NTRS)

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

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

1979-01-01

355

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

356

Radio science with Voyager 2 at Uranus - Results on masses and densities of the planet and five principal satellites  

NASA Technical Reports Server (NTRS)

Phase-coherent Doppler data generated by the Deep Space Network with the radio communication system during the Voyager 2 encounter with Uranus in January 1986, optical navigation data generated by the Voyager Navigation Team with the Voyager 2 imaging system, and ground-based astrometric data obtained over an 8-yr period are compiled and analyzed to determine the masses and densities of Uranus and its principal satellites. The data-analysis procedures are explained in detail, and the results are presented in tables and graphs. The mean density of Uranus is found to be 1.285 + or - 0.001 g/cu cm, whereas the mean uncompressed mass of all five satellites is 1.48 + or - 0.06 g/cu cm, or 0.10 g/cu cm above the density expected for a homogeneous solar mix of rock, H2O and NH3 ice, and CH4 as clathrate hydrate. This difference is tentatively attributed to the presence of 15 mass percent of pure graphite, which would provide the thermal conductivity required to keep the satellites cold and undifferentiated.

Anderson, J. D.; Campbell, J. K.; Jacobson, R. A.; Sweetnam, D. N.; Taylor, A. H.

1987-01-01

357

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

NASA Video Gallery

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

358

Identifying Performance Bottlenecks on Modern Microarchitectures using an Adaptable Probe  

E-print Network

- dimensional parameter space of machine characteristics. We therefore differentiate a "probe" from space. A probe, by contrast, is used to explore a con- tinuous, multidimensional parameter spaceIdentifying Performance Bottlenecks on Modern Microarchitectures using an Adaptable Probe Gorden

359

Lecture Notes on Langmuir Probe Diagnostics  

E-print Network

Lecture Notes on Langmuir Probe Diagnostics Francis F. Chen Electrical Engineering Department.............................................................................................. 1 I. The Probe Characteristic ..................................................................................... 5 E. Space potential

Chen, Francis F.

360

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.

361

The galilean satellites and Jupiter: Voyager 2 imaging science results  

USGS Publications Warehouse

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

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

1979-01-01

362

Voyager 1 assessment of Jupiter's planetary magnetic field  

NASA Technical Reports Server (NTRS)

An estimate of Jupiter's planetary magnetic field is obtained from the Voyager 1 observations of the Jovian magnetosphere. An explicit model for the magnetodisc current system is combined with a spherical harmonic model of the planetary field with both sets of parameters determined simultaneously using a nonlinear generalized inverse methodology. The resulting model fits the observations extremely well throughout the analysis interval (r 20 Jovian radii). The Jovian internal field model obtained from the Voyager 1 data is very similar to the octopole Pioneer 11 models. The best fitting magnetodisc lies in the centrifugal equator, 2/3 of the way between the rotational and magnetic equators, as appropriate for centrifugal loading of the magnetosphere by a cold plasma.

Connerney, J. E. P.; Acuna, M. H.; Ness, N. F.

1981-01-01

363

Voyager 2 Saturn encounter attitude and articulation control experience  

NASA Technical Reports Server (NTRS)

A description is given of the Voyager Attitude and Articulation Control System (AACS). The complex series of maneuvers required for Voyager 2 during the near encounter period to obtain fields and particle data, track the limb of Saturn during the earth occultation period, and reflect the RF beam off the Saturnian ring system are discussed. It is noted that some of these maneuvers involved rotating the spacecraft simultaneously about multiple axes while maintaining accurate pointing of the scan platform, a first for interplanetary missions. Also described are two anomalies experienced by the AACS during the near encounter period. The first was the significant roll attitude error that occurred shortly after all axis inertial control and that continued to grow until celestial reacquisition. The second was that the scan platform slewing in the azimuth axis stopped midway through the near encounter. These anomalies are analyzed, and their effect on future missions is assessed.

Hill, M.

1982-01-01

364

The body voyage as visual representation and art performance.  

PubMed

This paper looks at the notion of the body as an interior landscape that is made intelligible through visual representation. It discerns the key figure of the inner corporeal voyage, identifies its main elements and examines how contemporary artists working with performances and installations deal with it. A further aim with the paper is to discuss what kind of image of the body that is conveyed through medical visual technologies, such as endoscopy, and relate it to contemporary discussions on embodiment, embodied vision and bodily presence. The paper concludes with a recent exhibition by the French artist Christian Boltanski, which gives a somewhat different meaning to the idea of the body voyage. PMID:21936211

Olsén, Jan Eric

2011-01-01

365

Voyager Saturn encounter attitude and articulation control experience  

NASA Technical Reports Server (NTRS)

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

Carlisle, G.; Hill, M.

1981-01-01

366

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

367

Voyager 1 planetary radio astronomy observations near Jupiter  

NASA Technical Reports Server (NTRS)

Results from the first low-frequency radio receiver to be transported into the Jupiter magnetosphere are reported. Dramatic new information was obtained, both because Voyager was near or in Jupiter's radio emission sources and because it was outside the relatively dense solar wind plasma of the inner solar system. Extensive radio spectral arcs, from above 30 to about 1 MHz, occurred in patterns correlated with planetary longitude. A newly discovered kilometric wavelength radio source may relate to the plasma torus near Io's orbit. In situ wave resonances near closest approach define an electron density profile along the Voyager trajectory and form the basis for a map of the torus. Detailed studies are in progress and are outlined briefly.

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

1979-01-01

368

Voyager 1 Planetary Radio Astronomy Observations Near Jupiter  

NASA Technical Reports Server (NTRS)

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 MHz, occurred in patterns correlated with planetary longitude. A newly discovered kilometric wavelength radio source may relate to the plasma torus near Io's orbit. In situ wave resonances near closest approach define an electron density profile along the Voyager trajectory and form the basis for a map of the torus. Studies in progress are outlined briefly.

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

1979-01-01

369

Plasma waves near Saturn: Initial results from Voyager 1  

NASA Technical Reports Server (NTRS)

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

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

1981-01-01

370

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.

371

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

372

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

373

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

374

Voyager spacecraft radio observations of Jupiter: Initial cruise results  

Microsoft Academic Search

Jupiter's hectometric (HOM) wave-length radio emissions have been detected by the planetary radio astronomy instruments onboard the two Voyager spacecraft. The emission is surprisingly similar in morphology but opposite in polarization to the decametric (DAM) wavelength Jovian radio noise that has been observed with ground-based telescopes for more than two decades. The HOM emissions are predominantly left-hand polarized and their

M. L. Kaiser; M. D. Desch; A. C. Riddle; A. Lecacheux; J. B. Pearce; J. K. Alexander; J. W. Warwick; J. R. Thieman

1979-01-01

375

Review of the NASA Voyager spacecraft polycarbonate capacitor failure incident  

NASA Technical Reports Server (NTRS)

The premission failure of a Voyager spacecraft capacitor has prompted an investigation into the use of polycarbonate capacitors in high impedance circuits, during which capacitor failures were induced by thermal cycling together with extended periods at high temperature. Measurement of leakage path temperature coefficients indicates that there are two distinct leakage types whose mechanisms are complicated by movement within the capacitor during temperature changes. A novel system for pulse detection during capacitor burn-in and ramp testing has proven to be beneficial.

Ott, F. M.; Yen, S. P. S.; Somoano, R. B.

1985-01-01

376

Plasma wave observations at Uranus from Voyager 2  

Microsoft Academic Search

Radio emissions from Uranus were detected by the Voyager 2 plasma wave instrument about 5 days before closest approach at frequencies of 31.1 and 56.2 khz. The bow shock was identified by an abrupt broadband burst of electrostatic turbulence about 10 hours before closest approach at a radial distance of 23.5 ru. Once inside of the magnetosphere strong whistler mode

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

1986-01-01

377

Winds of Neptune - Voyager observations of cloud motions  

NASA Technical Reports Server (NTRS)

Results are presented on measurements of cloud motions in the atmosphere of Neptune, using high temporal and spatial resolution images acquired from Voyager cameras. The results obtained on cloud motions reveal a wide range of atmospheric periods between 12 and 21 hours, consistent with previous observations. The new results expand the latitudinal coverage, improve the determination of streak motions (especially near 30 deg N), and add statistical weight to altitudes already covered by previous measurements.

Limaye, Sanjay S.; Sromovsky, Lawrence A.

1991-01-01

378

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

379

The helium abundance of Uranus from Voyager measurements  

Microsoft Academic Search

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

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

1987-01-01

380

Voyager detection of nonthermal radio emission from Saturn  

NASA Technical Reports Server (NTRS)

The detection of bursts of nonthermal radio noise from Saturn by the planetary radio astonomy experiment onboard the Voyager spacecraft is discussed. The emissions occur near 200 kHz with a peak flux density comparable to higher frequency Jovian emissions. The radiation is right-hand polarized and is most likely emitted in the extraordinary magnetoionic mode from Saturn's northern hemisphere. Modulation is apparent in the data which is consistent with a planetary rotation period of 10 hr 39.9 min.

Kaiser, M. L.; Desch, M. D.; Warwick, J. W.; Pearce, J. B.

1980-01-01

381

Voyager detection of nonthermal radio emission from Saturn  

NASA Technical Reports Server (NTRS)

The planetary radio astronomy experiment on board the Voyager spacecraft has detected bursts of nonthermal radio noise from Saturn occurring near 200 kilohertz, with a peak flux density comparable to higher frequency Jovian emissions. The radiation is right-hand polarized and is most likely emitted in the extraordinary magnetoionic mode from Saturn's northern hemisphere. Modulation that is consistent with a planetary rotation period of 10 hours 39.9 minutes is apparent in the data.

Kaiser, M. L.; Desch, M. D.; Warwick, J. W.; Pearce, J. B.

1980-01-01

382

Voyager spacecraft radio observations of Jupiter: Initial cruise results  

NASA Technical Reports Server (NTRS)

Jupiter's low-frequency radio emission were detected by the planetary radio astronomy instruments onboard the two Voyager spacecraft. The emission is surprisingly similar in morphology but opposite in polarization to the high-frequency Jovian radio noise that were observed with ground-based telescopes for more than two decades. Several possible explanations for the behavior of the low-frequency emission are examined, but none of them is completely satisfactory.

Kaiser, M. L.; Desch, M. D.; Riddle, A. C.; Lecacheux, A.; Pearce, J. B.; Alexander, J. K.; Warwick, J. W.; Thieman, J. R.

1979-01-01

383

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

384

Planetary radio astronomy observations from Voyager-2 near Saturn  

NASA Technical Reports Server (NTRS)

Voyager-2 planetry radio astronomy measurements obtained near Saturn are discussed. They indicate that Saturnian kilometric radiation is emitted by a strong, dayside source at auroral latitudes in the northern hemisphere and by a weaker (by more than an order of magnitude) source at complementary latitudes in the southern hemisphere. These emissions are variable both due to Saturn's rotation and, on longer time scales, probably due to influences of the solar wind and the satellite Dione. The Saturn 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 a 10(h)11(m) + or - 5(m) episodic recurrence period but with an occurrence frequency of only of about 30 percent of that detected with Voyager-1. During the crossing of the ring plane at a distance of 2.88 R sub S, an intense noise event is interpreted to be consequence of the impact/vaporization/ionization of charged micron-size G-ring particles distributed over a total vertical thickness of about 1500 km.

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.

1981-01-01

385

A test for 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). The evidence is unclear, however, as to whether Voyager 1 has crossed the heliopause into the local interstellar medium or remains within the heliosheath. In this Letter we propose a test that will determine whether Voyager 1 has crossed the heliopause: If Voyager 1 remains in the heliosheath, the high densities observed must be due to compressed solar wind, with the consequence that Voyager 1 will encounter another current sheet, where the polarity of the magnetic field reverses. Voyager 1 observations can be used to predict that the next current sheet crossing is likely to occur during 2015.

Gloeckler, G.; Fisk, L. A.

2014-08-01

386

Developing utility tools to enhance Voyager access, search and workflow automation  

Microsoft Academic Search

Purpose – This paper aims to describe three utility tools developed at Texas A&M University Libraries, which were designed for quick access and search of the Voyager OPAC and the Voyager clients. Design\\/methodology\\/approach – The Voyager Canned Search Generator provides content creators with an automatic way to generate persistent links to catalog searches. Quick-Cat is an OPAC shortcut search tool.

Daniel Xiao; John Paul Fullerton

2008-01-01

387

DSN 70-meter antenna X-band gain, phase, and pointing performance, with particular application for Voyager 2 Neptune encounter  

NASA Technical Reports Server (NTRS)

The gain, phase, and pointing performance of the Deep Space Network (DSN) 70 m antennas are investigated using theoretical antenna analysis computer programs that consider the gravity induced deformation of the antenna surface and quadripod structure. The microwave effects are calculated for normal subreflector focusing motion and for special fixed-subreflector conditions that may be used during the Voyager 2 Neptune encounter. The frequency stability effects of stepwise lateral and axial subreflector motions are also described. Comparisons with recently measured antenna efficiency and subreflector motion tests are presented. A modification to the existing 70 m antenna pointing squint correction constant is proposed.

Slobin, S. D.; Bathker, D. A.

1988-01-01

388

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

389

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

PubMed

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

Cassou-Noguès, Pierre

2011-01-01

390

Heat pipe cooled probe  

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

391

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

NASA Technical Reports Server (NTRS)

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

Wolf, H.

1977-01-01

392

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

NASA Astrophysics Data System (ADS)

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

Zank, G. P.

2015-01-01

393

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

394

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

SciTech Connect

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

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

2012-12-10

395

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

396

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

397

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

398

Robots Explore the Farthest Reaches of Earth and Space  

NASA Technical Reports Server (NTRS)

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

2008-01-01

399

Uranus' southern circulation revealed by Voyager 2: Unique characteristics  

NASA Astrophysics Data System (ADS)

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

Karkoschka, Erich

2015-04-01

400

Probing the Solar System  

ERIC Educational Resources Information Center

Humans have always had the vision to one day live on other planets. This vision existed even before the first person was put into orbit. Since the early space missions of putting humans into orbit around Earth, many advances have been made in space technology. We have now sent many space probes deep into the Solar system to explore the planets and…

Wilkinson, John

2013-01-01

401

Voyager image processing at the Image Processing Laboratory  

NASA Technical Reports Server (NTRS)

This paper discusses new digital processing techniques as applied to the Voyager Imaging Subsystem and devised to explore atmospheric dynamics, spectral variations, and the morphology of Jupiter, Saturn and their satellites. Radiometric and geometric decalibration processes, the modulation transfer function, and processes to determine and remove photometric properties of the atmosphere and surface of Jupiter and its satellites are examined. It is exhibited that selected images can be processed into 'approach at constant longitude' time lapse movies which are useful in observing atmospheric changes of Jupiter. Photographs are included to illustrate various image processing techniques.

Jepsen, P. L.; Mosher, J. A.; Yagi, G. M.; Avis, C. C.; Lorre, J. J.; Garneau, G. W.

1980-01-01

402

Spectral Units on the Icy Galilean Satellites from Voyager Imagery  

NASA Astrophysics Data System (ADS)

We are performing new analyses of the visible Voyager imagery in order to more accurately define spectral units on the icy Galilean satellites in an attempt to provide the best context for the Galileo mission results. The Galileo imaging system and the NIMS, with a resolution of up to 1 km, are returning superior spectral imagery to Voyager but only for selected regions of the satellites. Therefore, the Voyager data remains an important source of information. We use revised Voyager spectral images, formatted in an image cube calculated by Granahan et al. [1] to produce improved mosaics of the icy satellites in a format similar to those of Nelson et al. [2]. However, these data are superior to those used in these and other earlier analyses [2,3] due to a better calibration and improved software which enable a more accurate smoothing of the boundaries between image frames reducing the chance of misconstruing irregularities in the photometric function correction for compositional differences. We are presenting displays of spectral units for Ganymede and Callisto with the color assignments indicative of the spectral nature of the unit. These satellites show consistent evidence of surface emplacement of materials of exogenic and endogenic origin. [1] Granahan, J.C., K.S. Polk, F.P. Fanale, and T.B. McCord (1996) Lunar Planet. Sci. XXVII (abstract), 443-444. [2] Nelson, M.L., T.B. McCord, R.N. Clark, T.V. Johnson, D.L. Matson, J.A. Mosher, and L.A. Soderblom (1986). Icarus 65, 129-151. [3] Johnson, R.E., M.L. Nelson, T.B. McCord, and J.C. Gradie (1988). Icarus 75, 423-436. Johnson, T.V., L.A. Soderblom, J.A. Mosher, G.E. Danielson, A. F. Cook, and P. Kupferman (1983).J. Geophys. Res. 88, 5789-5805. McEwen, A.S. (1986). J. Geophys. Res. 91, 8077-8097.

Hibbitts, C. A.; McCord, T. B.; Granahan, J. C.

1996-09-01

403

The Jupiter system through the eyes of Voyager 1  

USGS Publications Warehouse

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

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

1979-01-01

404

DETAIL OF PLAQUE COMMEMORATING THE JULY/ AUGUST 1958 VOYAGE OF ...  

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

DETAIL OF PLAQUE COMMEMORATING THE JULY/ AUGUST 1958 VOYAGE OF THE USS NAUTILUS (SSN-571) TO THE NORTH POLE. NOTE: THIS PLAQUE IS NOT LOCATED AT WHARFS S13-S19; IT IS AT THE SUBMARINE MEMORIAL PARK, ABOUT 1,000' SOUTH OF THE WHARFS. THE LOCATION AND ORIENTATION OF THIS PHOTO IS NOT SHOWN ON THE PHOTO KEY MAP - U.S. Naval Base, Pearl Harbor, Additional Piers and Quay Walls, S13 to S19, Northeast end of Magazine Loch, Pearl City, Honolulu County, HI

405

Post Voyager comparisons of the interiors of Uranus and Neptune  

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

406

The jupiter system through the eyes of voyager 1.  

PubMed

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, 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. PMID:17800430

Smith, B A; Soderblom, L A; Johnson, T V; Ingersoll, A P; Collins, S A; Shoemaker, E M; Hunt, G E; Masursky, H; Carr, M H; Davies, M E; Cook, A F; 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

1979-06-01

407

Planetary radio astronomy observations from Voyager 1 near Saturn  

NASA Technical Reports Server (NTRS)

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 electrostatic discharge, is unpolarized, extremely impulsive, loosely correlated with Saturn's rotation, and very broadband, appearing throughout the observing range of the experiment (20.4 kilohertz to 40.2 megahertz). Its sources appear to lie in the planetary rings.

Warwick, J. W.; Pearce, J. B.; Evans, D. R.; Carr, T. D.; Schauble, J. J.; Alexander, J. K.; Kaiser, M. L.; Desch, M. D.; Pedersen, M.; Lecacheux, A.

1981-01-01

408

Voyager photometry of Triton - Haze and surface photometric properties  

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

409

33 CFR 157.162 - Crude oil washing during a voyage.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Crude oil washing during a voyage. 157...TANK VESSELS CARRYING OIL IN BULK Crude Oil Washing (COW) System on Tank Vessels Cow Operations § 157.162 Crude oil washing during a voyage....

2010-07-01

410

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

Microsoft Academic Search

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

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

1989-01-01

411

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

E-print Network

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

Atreya, Sushil

412

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

SciTech Connect

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

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

1990-02-01

413

Electrical resistivity probes  

DOEpatents

A miniaturized electrical resistivity (ER) probe based on a known current-voltage (I-V) electrode structure, the Wenner array, is designed for local (point) measurement. A pair of voltage measuring electrodes are positioned between a pair of current carrying electrodes. The electrodes are typically about 1 cm long, separated by 1 cm, so the probe is only about 1 inch long. The electrodes are mounted to a rigid tube with electrical wires in the tube and a sand bag may be placed around the electrodes to protect the electrodes. The probes can be positioned in a borehole or on the surface. The electrodes make contact with the surrounding medium. In a dual mode system, individual probes of a plurality of spaced probes can be used to measure local resistance, i.e. point measurements, but the system can select different probes to make interval measurements between probes and between boreholes.

Lee, Ki Ha; Becker, Alex; Faybishenko, Boris A.; Solbau, Ray D.

2003-10-21

414

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

415

Magnetic field measurements at Jupiter by Voyagers 1 and 2: Daily plots of 48 second averages  

NASA Technical Reports Server (NTRS)

A series of 24 hour summary plots of the magnetic field, in 48-s average form, measured in the vicinity of Jupiter by the magnetometers onboard Voyagers 1 and 2 are presented. The Voyager 1 data cover the period from 27 February 1979 (day = 58) to 23 March (day = 82) inclusive, and the Voyager 2 data cover the period from 2 July 1979 (day = 183) to 14 August (day = 226) inclusive. Closest approach to the planet occurred on days 64 (AT 1205 UT) and 190 (AT 2230 UT) for Voyagers 1 and 2, respectively. Also included are: a description of the characteristics of the magnetometers, a brief description of the near-planet trajectories of the two spacecraft, a listing of the bow shock and magnetopause crossing times, and a bibliography containing Voyager-Jupiter related papers and reports.

Lepping, R. P.; Silverstein, M. J.; Ness, N. F.

1981-01-01

416

Recent Results from the Voyager 1 and 2 Plasma Instruments  

NASA Astrophysics Data System (ADS)

Voyager 1 and Voyager 2, launched in 1978, are now at radial distances of 94 AU and 75 AU and continue to return data daily. The plasma (PLS) instruments onboard both spacecraft were designed and built by M.I.T. The PLS instrument on V1 ceased normal operation after the Saturn fly-by in 1980 but is still able to return ``DC Mode" current measurements integrated over all energies when fluxes are high enough. Eventually the instrument was turned off for power-sharing reasons and remained off until May 2003 when, following the controversial termination shock event at V1 in August 2002, the V1 PLS instrument was turned back on. The V2 PLS instrument is undamaged and continues to work perfectly. In this paper we introduce interpretation of the recent DC Mode data from the V1 PLS instrument. Alongside this we present V2 plasma data from the largest events of recent years, notably the 2000 Bastille day event and the Halloween events of 2003. Using V2 plasma data we are able to estimate likely DC mode readings at V1 and we compare these predictions to actual measurements. Finally, a survey of the V2 data set shows the V2 Bastille and Halloween events may be members of a new class of events observed near interplanetary shocks. The events are characterised by pulses followed by "troughs" in the plasma density, which coincide with increases in plasma temperature and magnetic field strength.

Ashmall, J.; Richardson, J. D.

2004-12-01

417

Cosmic ray modulation - Voyager 2 observations, 1987-1988  

NASA Technical Reports Server (NTRS)

The intensity profile of cosmic rays above 70 MeV observed by Voyager 2 and its relation to the interplanetary magnetic field and plasma at the beginning of the new modulation cycle from day 190, 1987 to day 345, 1988 in the region from 23.3 AU to 27.8 AU is analyzed. The cosmic ray intensity profile was approximately a series of four plateaus separated by three steps in which the intensity dropped abruptly. Each step was associated with a region in which the magnetic field, density and temperature were higher than average. The plateaus were associated with regions in which the magnetic field was alternately strong and weak. The solar wind within 200 AU during this interval can be roughly pictured as consisting of three shells between which the flow was quasiperiodic with a 26 day periodicity. The latitudinal extent of the shells in the northern hemisphere was probably less than 33 deg, since no steps were observed by Voyager 1. Drift motions might play a role during the recovery phase, just prior to the onset of the new modulation cycle, in the plateau regions between the shells, within the shells where drifts in various directions might mimic diffusion, and close to 1 AU, where large regions of intense magnetic fields have not yet formed. However the principal decreases in the cosmic ray intensity in the outer heliosphere during 1987 and 1988 were associated with the passage of broad regions of intense magnetic fields, consistent with the diffusion/convection model.

Burlaga, L. F.; Mcdonald, F. B.; Ness, N. F.; Lazarus, A. J.

1991-01-01

418

Encounter with Saturn: Voyager 1 imaging science results  

USGS Publications Warehouse

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

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

1981-01-01

419

Multifractal Structures Detected by Voyager 1 at the Heliospheric Boundaries  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

420

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

421

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

E-print Network

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

Richardson, John

422

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

Microsoft Academic Search

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

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

2005-01-01

423

ALEX neutral beam probe  

SciTech Connect

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

Pourrezaei, K.

1982-01-01

424

Time, space, and permission for entrepreneurs  

E-print Network

the human-animal bond The Voyager Alumna never turns down adventure #12;contents Sparks: "Time, space.S. and Vir- ginia in particular. Campus canines: Exploring the human-animal bond "One second they're gnawing of the pen." So goes a researcher's effort to film puppies in 3-D, just one of the fascinating ways that dogs

Liskiewicz, Maciej

425

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

426

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

427

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

SciTech Connect

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

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

2008-08-15

428

The Voyager 2 encounter with the Neptunian system  

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

429

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

430

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

431

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

432

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.

Chuck Meertens

2002-02-28

433

EUV emission from Titan's upper atmosphere - Voyager 1 encounter  

NASA Technical Reports Server (NTRS)

Most of the observed emission short of Lyman-alpha is shown to be accounted for by electron impact on N2 above 3600 km, in an analysis of Titan's EUV emission spectra obtained at the Voyager 1 encounter. It is determined that N2 is the major component of Titan's upper atmosphere, with 3900-km upper limit mixing ratios of NeI, ArI, CO, H2, and HI of 0.01, 0.06, 0.05, 0.06 and 0.1, respectively. Magnetospheric electron precipitation produces an average dayside electron density of about 3000/cu cm between 3600 and 4000 km, which is the region of bright limb emission, and magnetospheric electron impact dissociation of N2 generates an N atom escape rate of 3 x 10 to the 26th/sec from Titan's exosphere when Titan is within Saturn's magnetosphere.

Strobel, D. F.; Shemansky, D. E.

1982-01-01

434

Voyager spacecraft radio observations of Jupiter - Initial cruise results  

NASA Technical Reports Server (NTRS)

Low frequency (below 1326 kHz) observations of Jupiter obtained from November, 1977 through June, 1978 by the radio astronomy receivers carried by the two Voyager spacecraft are reported and compared with a large body of higher-frequency ground-based observations. Although the morphology of hectometric wavelength (HOM) emissions strongly resembles that of decametric (DAM) wavelength radio noise, they display opposite polarization. DAM emissions are strongly modulated by Io, whereas HOM emissions exhibit little or no influence from any satellite and appear to be modulated by the rotation phase of the planet. Several single-source models could possibly account for these results, including a model assuming emission at two well-separated frequencies above and below the local electron plasma frequency and the model proposed by Barbosa (1976) in which electrostatic waves at twice the upper hybrid frequency couple to both the ordinary and extraordinary electromagnetic modes. However, neither of these is entirely satisfactory.

Kaiser, M. L.; Desch, M. D.; Alexander, J. K.; Thieman, J. R.; Riddle, A. C.; Pearce, J. B.; Warwick, J. W.; Lecacheux, A.

1979-01-01

435

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.

436

DNA Microarray Probe , syshin, ihlee, btzhang}@bi.snu.ac.kr  

E-print Network

algorithms(MOEA) probe , . MOEA convergence diversity solution [2]. -MOEA[1] objective , . probe search space . primer probe MOEA search space , 2) 3) ratio probe quality . , parameter primer , primer - MOEA search space - MOEA primer sequence probe . , primer probe guidance . 2.2 -MOEA Pareto-optimal set MOEA fitness

437

Voyager 2 in the Uranian system: Imaging science results  

USGS Publications Warehouse

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

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

1986-01-01

438

Voyager aircraft return from non-stop trip around the world  

NASA Technical Reports Server (NTRS)

The Voyager aircraft circles before landing at Edwards Air Force Base, Edwards, California, to complete it's record breaking, nonstop unfueled flight around the world. The Voyager landed at Edwards at 8:06 a.m. PST Dec. 23, 1986, after a nine-day flight. Richard Rutan and Jeana Yeager piloted the aircraft from a cramped cockpit. Voyager's takeoff weight was more than 10 times the structural weight, but its drag was lower than almost any other powered aircraft. The aircraft's design and light-weight structural materials allowed it to carry an unprecedented amount of fuel on its 25,000 mile flight. Voyager took off from Edwards Dec. 14, and traveled at an average speed of 115.8 mph. The 9 day, 3 minute, 44 sec. flight nearly doubled the previous distance record set in 1962 by a USAF/Boeing B-52H.

1986-01-01

439

46 CFR 14.203 - Voyages upon which shipping articles are not required.  

Code of Federal Regulations, 2010 CFR

... Shipping 1 2010-10-01 2010-10-01 false Voyages upon which shipping articles are not required...vessel is employed exclusively in trade on the Great Lakes, other lakes, bays, sounds, bayous, canals, or...

2010-10-01

440

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

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

441

Earth Exploration Toolbook Chapter: Investigating Earthquakes with ArcVoyager GIS  

NSDL National Science Digital Library

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

Carla McAuliffe

442

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

E-print Network

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

Morshed, Adnan Zillur

1995-01-01

443

Publications 2009 Alien Ocean: Anthropological Voyages in Microbial Seas. Berkeley: University of  

E-print Network

Publications Books 2009 Alien Ocean: Anthropological Voyages in Microbial Seas. Berkeley, Committee on the Anthropology of Science, Technology & Computing, American Anthropological Association Ecosystems, from Artisanal Cheese to Alien Seas (with Heather Paxson). Social Studies of Science, in press

Polz, Martin

444

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

SciTech Connect

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

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

2012-09-01

445

Reply to 'A Comment on '"The Far Future of Exoplanet Direct Characterization" - the Case for Interstellar Space Probes'  

E-print Network

Reply to A Comment on The Far Future of Exoplanet Direct Characterization - the Case for Interstellar Space Probess by Ian Crawford. The paper The Far Future of Exoplanet Direct Characterization resulted from the collective work of TE-SAT, a team appointed by ESA in 2003 to assess a strategy to find and characterize Terrestrial Exoplanets. The interstellar flight aspect was not part of the TE-SAT work and was added afterward as side remarks in the chapter on {\\guillemotleft} The Far Future of Exoplanet Direct Characterization {\\guillemotright}. As an introductory general remark, the intention of the paper was not to discourage work on interstellar flight prospective. On the contrary, any advance in this field that makes interstellar travel closer to us is welcome. In the framework of this short reply, the discussion can only be qualitative; it would deserve a full future paper.

Schneider, Jean

2010-01-01

446

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

447

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

448

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

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

449

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

450

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

451

Probe Measurements on High Pressure Arcs  

Microsoft Academic Search

The introduction of a probe in a carbon arc in air at atmospheric pressure has been found to increase the arc voltage by several volts, the increase being almost independent of the velocity with which the probe is moved, but being a function of probe perimeter. Observation showed that the probe was surrounded by a dark space, with a fairly

R. C. Mason

1937-01-01

452

Inflatable traversing probe seal  

NASA Technical Reports Server (NTRS)

An inflatable seal acts as a pressure-tight zipper to provide traversing capability for instrumentation rakes and probes. A specially designed probe segment with a teardrop cross-section in the vicinity of the inflatable seal minimizes leakage at the interface. The probe is able to travel through a lengthwise slot in a pressure vessel or wind tunnel section, while still maintaining pressure integrity. The design uses two commercially available inflatable seals, opposing each other, to cover the probe slot in a wind tunnel wall. Proof-of-concept tests were conducted at vessel pressures up to 30 psig, with seals inflated to 50 psig, showing no measurable leakage along the seal's length or around the probe teardrop cross-section. This seal concept can replace the existing technology of sliding face plate/O-ring systems in applications where lengthwise space is limited.

Trimarchi, Paul A.

1991-01-01

453

Quantum-cryptographic entangling probe  

NASA Astrophysics Data System (ADS)

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

Brandt, Howard E.

2005-04-01

454

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

455

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.

2014-09-18

456

Scanning Probe Microscopy  

NSDL National Science Digital Library

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

457

Synthetic Micro/Nanomachines and Their Applications: Towards 'Fantastic Voyage'  

NASA Astrophysics Data System (ADS)

The 1966 movie Fantastic Voyage captured the world's imagination, portraying a tiny submarine navigating through the human bloodstream and treating life-threatening medical conditions. My PhD research focuses on the synthetic nano/microscale machines to realize the Fantastic Voyage vision. Various biomedical and environmental areas would benefit from the developments of efficient fuel-free and fuel-driven nano/microscale machines. The polymer-based catalytic tubular microengine is synthesized using a template based electrodeposition method. The oxygen bubble propelled microengine harvests the energy from chemical fuels (such as H2O2) and displays very efficient propulsion. It can serve as an ideal platform for diverse biomedical and environmental applications. For example, lectin modified polyaniline based microengines can be used for selective bacteria (E. Coli) isolation from food, clinical and environmental samples; poly(3-aminophenylboronic acid)/Ni/Pt microengine itself provides the 'built in' glucose recognition capability for 'on-the-fly' capture, transport and release of yeast cells. A series of micromotors which can be self-propelled in natural environments without additional chemical fuels are developed, holding great promise for in vivo biomedical applications: the polyaniline/zinc microrockets display effective autonomous motion in extreme acidic environments (such as human stomach); the Al-Ga/Ti based Janus micromotor can be propelled by the hydrogen bubbles generated from the rapid aluminum and water reaction; alkanethiols modified seawater-driven Mg Janus micromotors, which utilize macrogalvanic corrosion and chloride pitting corrosion processes, can be used for environmental oil remediation. Magnetically powered nanoswimmers have attracted considerable attention due to their great biocompatibility. A high-speed magnetically-propelled nanowire swimmer which mimics swimming microorganisms by exploiting the flexible nanowire as artificial flagella under rotating magnetic field is illustrated. New bioinspired microswimmers can also be prepared directly from isolated spiral vessels of plants, harnessing the intrinsic biological structures of nature. Potential applications of these cargo-towing nanoswimmers are demonstrated by the directed delivery of drug-loaded microparticles to HeLa cancer cells in biological media. With such innovations and developments, along with careful attention to key challenges and requirements, nano/microscale motors are expected to have tremendous impact on diverse biomedical and environmental applications, providing unlimited opportunities limited only by one's imagination.

Gao, Wei

458

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

459

Standing Alfven wave current system at Io: Voyager 1 observations  

NASA Technical Reports Server (NTRS)

The enigmatic control of the occurrence frequency of Jupiter's decametric emissions by the satellite Io is explained theoretically on the basis of its strong electrodynamic interaction with the corotating Jovian magnetosphere leading to field aligned currents connecting Io with the Jovian ionosphere. Direct measurements of the perturbation magnetic fields due to this current system were obtained by the magnetic field experiment on Voyager 1 on 5 March 1979 when it passed within 20,500 km south of Io. An interpretation in the framework of Alfven waves radiated by Io leads to current estimates of 2.8 million amps. A mass density of 7400 to 13600 proton mass units per Cu cm is derived which compares very favorably with independent observations of the torus composition characterized by 7-9 proton mass units per electron for a local electron density of 1050 to 1500 per cu cm. The power dissipated in the current system may be important for heating the Io heavy ion torus, inner magnetosphere, Jovian ionosphere, and possibly the ionosphere or even the interior of Io.

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

1980-01-01

460

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

461

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

462

Rocket exhaust plume impingement on the Voyager spacecraft  

NASA Technical Reports Server (NTRS)

In connection with the conduction of the long-duration Voyager missions to the outer planets and the sophisticated propulsion systems required, it was necessary to carry out an investigation to avoid exhaust plume impingement problems. The rarefied gas dynamics literature indicates that, for most engineering surfaces, the assumption of diffuse reemission and complete thermal accommodation is warranted in the free molecular flow regime. This assumption was applied to an analysis of a spacecraft plume impingement problem in the near-free molecular flow regime and yielded results to within a few percent of flight data. The importance of a correct treatment of the surface temperature was also demonstrated. Specular reflection, on the other hand, was shown to yield results which may be unconservative by a factor of 2 or 3. It is pointed out that one of the most difficult portions of an exhaust plume impingement analysis is the simulation of the impinged hardware. The geometry involved must be described as accurately and completely as possible.

Baerwald, R. K.

1978-01-01

463

The helium abundance of Uranus from Voyager measurements  

NASA Technical Reports Server (NTRS)

Voyager radio-occultation and IR spectroscopy measurements are combined to infer an He mole fraction in the upper troposphere of Uranus of 0.152 + or - 0.033; the corresponding mass fraction is Y = 0.262 + or - 0.048. This value is in agreement with recent estimates of the solar He abundance, suggesting that He differentiation has not occurred on Uranus. Comparisons with values previously obtained for Jupiter and Saturn imply that migration of He toward the core began long ago on Saturn and may also have recently begun on Jupiter. The protosolar He abundance inferred from the Uranus measurements and from recent solar evolutionary models is used along with an assumed primordial He mass fraction of 0.23-0.24 to estimate a 3-4-percent enrichment of He in the interstellar medium between the big bang and the origin of the solar system. The result is in agreement with galactic chemical evolution models which include a substantial decrease in D during the evolutionary process.

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

1987-01-01

464

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.

465

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

466

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

Microsoft Academic Search

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

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

1997-01-01

467

Atmospheric entry probes for outer planet exploration. Outer planet entry probe technical summary  

NASA Technical Reports Server (NTRS)

The use of unmanned space probes for investigating the conditions existing on and around the outer planets of the solar system is discussed. The subjects included in the report are: (1) the design of a common entry probe for outer planet missions, (2) the significant trades related to the development of a common probe design, (3) the impact of bus selection on probe design, (4) the impact of probe requirements on bus modifications, and (5) the key technology elements recommended for advanced development. Drawings and illustrations of typical probes are included to show the components and systems used in the space probes.

1974-01-01

468

Climate windows for Polynesian voyaging to New Zealand and Easter Island  

PubMed Central

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

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

2014-01-01

469

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

PubMed

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

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

2014-10-14

470

RADIAL VELOCITY ALONG THE VOYAGER 1 TRAJECTORY: THE EFFECT OF SOLAR CYCLE  

SciTech Connect

As Voyager 1 and Voyager 2 are approaching the heliopause (HP)-the boundary between the solar wind (SW) and the local interstellar medium (LISM)-we expect new, unknown features of the heliospheric interface to be revealed. A seeming puzzle reported recently by Krimigis et al. concerns the unusually low, even negative, radial velocity components derived from the energetic ion distribution. Steady-state plasma models of the inner heliosheath (IHS) show that the radial velocity should not be equal to zero even at the surface of the HP. Here we demonstrate that the velocity distributions observed by Voyager 1 are consistent with time-dependent simulations of the SW-LISM interaction. In this Letter, we analyze the results from a numerical model of the large-scale heliosphere that includes solar cycle effects. Our simulations show that prolonged periods of low to negative radial velocity can exist in the IHS at substantial distances from the HP. It is also shown that Voyager 1 was more likely to observe such regions than Voyager 2.

Pogorelov, N. V.; Zank, G. P. [Physics Department, The University of Alabama in Huntsville, AL 35805 (United States); Borovikov, S. N. [Center for Space Physics and Aeronomic Research, The University of Alabama in Huntsville, AL 35805 (United States); Burlaga, L. F. [Geospace Physics Laboratory, Code 673, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Decker, R. A. [Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723 (United States); Stone, E. C. [Space Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States)

2012-05-01

471

Radial Velocity along the Voyager 1 Trajectory: The Effect of Solar Cycle  

NASA Astrophysics Data System (ADS)

As Voyager 1 and Voyager 2 are approaching the heliopause (HP)—the boundary between the solar wind (SW) and the local interstellar medium (LISM)—we expect new, unknown features of the heliospheric interface to be revealed. A seeming puzzle reported recently by Krimigis et al. concerns the unusually low, even negative, radial velocity components derived from the energetic ion distribution. Steady-state plasma models of the inner heliosheath (IHS) show that the radial velocity should not be equal to zero even at the surface of the HP. Here we demonstrate that the velocity distributions observed by Voyager 1 are consistent with time-dependent simulations of the SW-LISM interaction. In this Letter, we analyze the results from a numerical model of the large-scale heliosphere that includes solar cycle effects. Our simulations show that prolonged periods of low to negative radial velocity can exist in the IHS at substantial distances from the HP. It is also shown that Voyager 1 was more likely to observe such regions than Voyager 2.

Pogorelov, N. V.; Borovikov, S. N.; Zank, G. P.; Burlaga, L. F.; Decker, R. A.; Stone, E. C.

2012-05-01

472

Observation of the multifractal spectrum in the heliosphere and the heliosheath by Voyager 1 and 2  

NASA Astrophysics Data System (ADS)

We present first results of the multifractal scaling of the fluctuations of the interplanetary magnetic field strength as measured onboard Voyager 2 in the very distant heliosphere and even in the heliosheath. More specifically, the spectra observed by Voyager 2 in a wide range of heliospheric distances from 6 to 90 astronomical units (AU) are compared with those of Voyager 1 already analyzed between 7 and 107 AU. We focus on the singularity multifractal spectrum before and after crossing the termination heliospheric shock by Voyager 1 at 94 AU and Voyager 2 at 84 AU from the Sun. It is worth noting that the spectrum is prevalently right-skewed inside the whole heliosphere. Moreover, we have observed a change of the asymmetry of the spectrum at the termination shock, where the spectrum changes from (left-) right-skewed in the very distant heliosphere to the (right-) left-skewed or possibly symmetric spectrum in the heliosheath. We confirm that the degree of multifractality falls steadily with the distance from the Sun. In addition, the multifractal structure is apparently modulated by the solar activity, with a time shift of several years, corresponding to a distance of about 10 AU, resulting from the evolution of the whole heliosphere. Hence this basic result also brings significant additional support to some earlier claims suggesting that the solar wind termination shock is asymmetric.

Macek, W. M.; Wawrzaszek, A.; Carbone, V.

2012-12-01

473

Long-range planning cost model for support of future space missions by the deep space network  

NASA Technical Reports Server (NTRS)

A simple model is suggested to do long-range planning cost estimates for Deep Space Network (DSP) support of future space missions. The model estimates total DSN preparation costs and the annual distribution of these costs for long-range budgetary planning. The cost model is based on actual DSN preparation costs from four space missions: Galileo, Voyager (Uranus), Voyager (Neptune), and Magellan. The model was tested against the four projects and gave cost estimates that range from 18 percent above the actual total preparation costs of the projects to 25 percent below. The model was also compared to two other independent projects: Viking and Mariner Jupiter/Saturn (MJS later became Voyager). The model gave cost estimates that range from 2 percent (for Viking) to 10 percent (for MJS) below the actual total preparation costs of these missions.

Sherif, J. S.; Remer, D. S.; Buchanan, H. R.

1990-01-01

474

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

475

The Asymmetric Current Mirror Probe  

NASA Astrophysics Data System (ADS)

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

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

2008-11-01

476

Voyages...voyages.  

ERIC Educational Resources Information Center

Four teachers from Norway, Italy, and Hungary have found ways to actively prepare their students for overseas exchanges, using student correspondence, discussion of current events, exercises in formulating questions, and student language skill development projects to elevate the visit above superficial tourism. (MSE)

Saraceni, Luisa; And Others

1990-01-01

477

Geological assessment probe  

NASA Technical Reports Server (NTRS)

A probe is described which can be installed in a side hole that extends from a bore hole in the Earth, to assess the permeability of the strata surrounding the borehole. The probe is elongated and has a plurality of seals spaced therealong and sealed to the walls of the side hole to form a plurality of chambers sealed from one another. A tracer fluid injector on the probe can inject a tracer fluid into one of the chambers, while a tracer fluid detector located in another chamber can detect the tracer fluid, to thereby sense the permeability of the strata surrounding the side hole. The probe can include a train of modules, with each module having an inflatable packer which is inflated by the difference between the borehole pressure and the strata pressure.

Collins, E. R. (inventor)

1980-01-01

478

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

479

On the Cell Probe Complexity of Membership and Perfect Hashing  

E-print Network

's cell probe model. The #12;rst space and bit probe optimal worst case upper bound is givenOn the Cell Probe Complexity of Membership and Perfect Hashing #3; Rasmus Pagh BRICS y , Department adaptive choice, and probes a total of three words. A lower bound shows that two word probes generally do

Pagh, Rasmus

480

On the Cell Probe Complexity of Membership and Perfect Hashing  

E-print Network

's cell probe model. The first space and bit probe optimal worst case upper bound is givenOn the Cell Probe Complexity of Membership and Perfect Hashing Rasmus Pagh BRICS , Department adaptive choice, and probes a total of three words. A lower bound shows that two word probes generally do

Pagh, Rasmus

481

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01