Science.gov

Sample records for original constellation points

  1. On the origin of the zodiacal constellations

    NASA Astrophysics Data System (ADS)

    Gurshtein, Alex A.

    A reconstruction of the evolution of the zodiacal constellations is made, based on the Indoeuropean and Sumero-Akkadian religio-cultural data, including artifacts such as cult statuettes, cuneiform tablets, cylinder seals and boundary stones. It is argued that the development of the twelve houses of the zodiac in three groups of four over some six millennia was dictated by the changes made by precession in the positions of the vernal and autumnal equinoxes and the winter and summer solstices.

  2. Origins of the ancient constellations: II. The Mediterranean traditions

    NASA Astrophysics Data System (ADS)

    Rogers, J. H.

    1998-04-01

    The classical map of the sky, with the 48 Greek constellations, was derived from at least two different pre-Greek traditions. One tradition comprised the 12 signs of the zodiac, with several associated animal constellations, all of which developed over ~3200-500 BC in Mesopotamia in a religious or ritual tradition. These were taken over by the Greeks around 500 BC. However the other Babylonian constellations, their farming-calendar tradition, were not adopted. The other tradition was not Mesopotamian; it comprised large constellations which appear to date from ~2800 BC, probably from the Mediterranean region, devised for the navigators of ships. They include huge bears and serpents which marked the celestial pole and equator at that time, and probably the four anonymous giants which we know as Hercules, Ophiuchus, Bootes, and Auriga, as well as some of the large southern 'marine' constellations. The origins of some other constellations, including the Perseus tableau and various animals, are unknown; they may have been new creations of the Greeks. The Greeks assembled the classical sky-map from these different sources between 540-370 BC, but many of the familiar legends were only applied to the constellations later.

  3. A New Synthesis for the Origin of the Greek Constellations

    NASA Astrophysics Data System (ADS)

    Schaefer, B. E.

    2005-08-01

    The Greek constellations constitute one of the longest enduring intellectual properties of humanity. While various papers attribute the origin of the constellations to many diverse possibilities, main stream historians view the origin as largely being in Mesopotamia after around 1350 BC with transmission to the Greeks around 500 BC or so. The evidence for this synthesis is cuneiform and iconographic records that first mention constellations from roughly 1350-500 BC. My recent research on precessional dating has added much detail to this old synthesis. The earliest surviving written description of the Greek constellations is Aratus' Phaenomenon, which is a copy of Eudoxus' lost book of the same name. Hipparchus' Commentary also extensively quotes from Eudoxus. With 172 observations from Eudoxus, I derive a precessional date of 1130 ± 80 BC and a latitude of 36.0 ± 0.9 degrees north. Further, the positioning of the southern void amongst the Greek constellations yields a date of 690 BC (with an uncertainty of 2-4 centuries) and a latitude of 33 degrees (with an uncertainty of 1-3 degrees) for the six southernmost constellations. The earliest surviving description of the Mesopotamian constellations is the MUL.APIN tablet series, with the oldest dated example from the 8th century BC. My precessional calculation gives a date of 1100 BC and a latitude of 33 north. I also see that Eudoxus and MUL.APIN share a substantial number of observations. In all, some Assyrian observer(s) between 33-36 degrees north latitude around the time of 1300-1000 BC apparently invented many of the constellations adopted by the Greeks and made a database of observations later repeated by MUL.APIN, Eudoxus, Aratus, and Hipparchus. But this is not the whole story, as this only accounts for 19 Greek constellations which are identical in stars and representation with the Mesopotamian sky. An additional 12 Greek constellations have the same star groups as the Babylonians yet have completely

  4. Precise Point Positioning Using Triple GNSS Constellations in Various Modes.

    PubMed

    Afifi, Akram; El-Rabbany, Ahmed

    2016-05-28

    This paper introduces a new dual-frequency precise point positioning (PPP) model, which combines the observations from three different global navigation satellite system (GNSS) constellations, namely GPS, Galileo, and BeiDou. Combining measurements from different GNSS systems introduces additional biases, including inter-system bias and hardware delays, which require rigorous modelling. Our model is based on the un-differenced and between-satellite single-difference (BSSD) linear combinations. BSSD linear combination cancels out some receiver-related biases, including receiver clock error and non-zero initial phase bias of the receiver oscillator. Forming the BSSD linear combination requires a reference satellite, which can be selected from any of the GPS, Galileo, and BeiDou systems. In this paper three BSSD scenarios are tested; each considers a reference satellite from a different GNSS constellation. Natural Resources Canada's GPSPace PPP software is modified to enable a combined GPS, Galileo, and BeiDou PPP solution and to handle the newly introduced biases. A total of four data sets collected at four different IGS stations are processed to verify the developed PPP model. Precise satellite orbit and clock products from the International GNSS Service Multi-GNSS Experiment (IGS-MGEX) network are used to correct the GPS, Galileo, and BeiDou measurements in the post-processing PPP mode. A real-time PPP solution is also obtained, which is referred to as RT-PPP in the sequel, through the use of the IGS real-time service (RTS) for satellite orbit and clock corrections. However, only GPS and Galileo observations are used for the RT-PPP solution, as the RTS-IGS satellite products are not presently available for BeiDou system. All post-processed and real-time PPP solutions are compared with the traditional un-differenced GPS-only counterparts. It is shown that combining the GPS, Galileo, and BeiDou observations in the post-processing mode improves the PPP convergence

  5. Precise Point Positioning Using Triple GNSS Constellations in Various Modes

    PubMed Central

    Afifi, Akram; El-Rabbany, Ahmed

    2016-01-01

    This paper introduces a new dual-frequency precise point positioning (PPP) model, which combines the observations from three different global navigation satellite system (GNSS) constellations, namely GPS, Galileo, and BeiDou. Combining measurements from different GNSS systems introduces additional biases, including inter-system bias and hardware delays, which require rigorous modelling. Our model is based on the un-differenced and between-satellite single-difference (BSSD) linear combinations. BSSD linear combination cancels out some receiver-related biases, including receiver clock error and non-zero initial phase bias of the receiver oscillator. Forming the BSSD linear combination requires a reference satellite, which can be selected from any of the GPS, Galileo, and BeiDou systems. In this paper three BSSD scenarios are tested; each considers a reference satellite from a different GNSS constellation. Natural Resources Canada’s GPSPace PPP software is modified to enable a combined GPS, Galileo, and BeiDou PPP solution and to handle the newly introduced biases. A total of four data sets collected at four different IGS stations are processed to verify the developed PPP model. Precise satellite orbit and clock products from the International GNSS Service Multi-GNSS Experiment (IGS-MGEX) network are used to correct the GPS, Galileo, and BeiDou measurements in the post-processing PPP mode. A real-time PPP solution is also obtained, which is referred to as RT-PPP in the sequel, through the use of the IGS real-time service (RTS) for satellite orbit and clock corrections. However, only GPS and Galileo observations are used for the RT-PPP solution, as the RTS-IGS satellite products are not presently available for BeiDou system. All post-processed and real-time PPP solutions are compared with the traditional un-differenced GPS-only counterparts. It is shown that combining the GPS, Galileo, and BeiDou observations in the post-processing mode improves the PPP convergence

  6. Origins of the ancient constellations: I. The Mesopotamian traditions

    NASA Astrophysics Data System (ADS)

    Rogers, J. H.

    1998-02-01

    In the sky-map of ancient Babylon, constellations had two different roles, and thus developed into two overlapping traditions. One set of constellations represented the gods and their symbols; the other set represented rustic activities and provided a farming calendar. Many constellations were shared by the two traditions, but in some regions of sky there were alternative divine and rustic figures. These figures developed in stages from ~3200 BC to ~500 BC. Of the divine set, the most important (although the last to be finalised) were the twelve zodiacal signs, plus several associated animals (the serpent, crow, eagle, and fish), which were all transmitted to the classical Greek sky-map that we still use today. Conversely, the rustic constellations of workers and tools and animals were not transmitted to the West. However, a few of them may have survived in Bedouin Arab sky-maps of the first millennium AD.

  7. Registration of Vehicle-Borne Point Clouds and Panoramic Images Based on Sensor Constellations.

    PubMed

    Yao, Lianbi; Wu, Hangbin; Li, Yayun; Meng, Bin; Qian, Jinfei; Liu, Chun; Fan, Hongchao

    2017-04-11

    A mobile mapping system (MMS) is usually utilized to collect environmental data on and around urban roads. Laser scanners and panoramic cameras are the main sensors of an MMS. This paper presents a new method for the registration of the point clouds and panoramic images based on sensor constellation. After the sensor constellation was analyzed, a feature point, the intersection of the connecting line between the global positioning system (GPS) antenna and the panoramic camera with a horizontal plane, was utilized to separate the point clouds into blocks. The blocks for the central and sideward laser scanners were extracted with the segmentation feature points. Then, the point clouds located in the blocks were separated from the original point clouds. Each point in the blocks was used to find the accurate corresponding pixel in the relative panoramic images via a collinear function, and the position and orientation relationship amongst different sensors. A search strategy is proposed for the correspondence of laser scanners and lenses of panoramic cameras to reduce calculation complexity and improve efficiency. Four cases of different urban road types were selected to verify the efficiency and accuracy of the proposed method. Results indicate that most of the point clouds (with an average of 99.7%) were successfully registered with the panoramic images with great efficiency. Geometric evaluation results indicate that horizontal accuracy was approximately 0.10-0.20 m, and vertical accuracy was approximately 0.01-0.02 m for all cases. Finally, the main factors that affect registration accuracy, including time synchronization amongst different sensors, system positioning and vehicle speed, are discussed.

  8. Registration of Vehicle-Borne Point Clouds and Panoramic Images Based on Sensor Constellations

    PubMed Central

    Yao, Lianbi; Wu, Hangbin; Li, Yayun; Meng, Bin; Qian, Jinfei; Liu, Chun; Fan, Hongchao

    2017-01-01

    A mobile mapping system (MMS) is usually utilized to collect environmental data on and around urban roads. Laser scanners and panoramic cameras are the main sensors of an MMS. This paper presents a new method for the registration of the point clouds and panoramic images based on sensor constellation. After the sensor constellation was analyzed, a feature point, the intersection of the connecting line between the global positioning system (GPS) antenna and the panoramic camera with a horizontal plane, was utilized to separate the point clouds into blocks. The blocks for the central and sideward laser scanners were extracted with the segmentation feature points. Then, the point clouds located in the blocks were separated from the original point clouds. Each point in the blocks was used to find the accurate corresponding pixel in the relative panoramic images via a collinear function, and the position and orientation relationship amongst different sensors. A search strategy is proposed for the correspondence of laser scanners and lenses of panoramic cameras to reduce calculation complexity and improve efficiency. Four cases of different urban road types were selected to verify the efficiency and accuracy of the proposed method. Results indicate that most of the point clouds (with an average of 99.7%) were successfully registered with the panoramic images with great efficiency. Geometric evaluation results indicate that horizontal accuracy was approximately 0.10–0.20 m, and vertical accuracy was approximately 0.01–0.02 m for all cases. Finally, the main factors that affect registration accuracy, including time synchronization amongst different sensors, system positioning and vehicle speed, are discussed. PMID:28398256

  9. Rannyaya istoriya Mesopotamskikh sozvezdij (k probleme proiskhozhdeniya sozvezdij) %t The early history of Mesopotamian constellations (to the problem of the constellations origin

    NASA Astrophysics Data System (ADS)

    Kurtik, G. E.

    This paper considers the early written and iconographic sources of the end of the 4th-beginning of the 2nd millennia B.C. which can shed light on the problem of the origin of Mesopotamian constellations. We were interested, first of all, with two questions: (1) whether it is possible to make a conclusion on the basis of the sources that the constellations were already distinguished in Mesopotamia in the appropriate period, and, if-yes, (2) what constellation or group of constellations is there the question about? In most cases the conclusion turns out to be either negative or uncertain because the sources allow ambiguous, sometimes opposite senses, interpretations.

  10. An Analysis of the Impact of AN Improved Gnss Constellation on Precise Point Positioning

    NASA Astrophysics Data System (ADS)

    Garcia, Carlos; Leandro, Rodrigo; Santos, Marcelo; Langley, Richard

    During the past few years there have been an increasing number of GNSS research studies on the predicted impact on positioning due to the implementation and use of Galileo and GLONASS alongside GPS. It is expected that some years from now these other two satellite constellations will be complete and therefore there would be around about three times more GNSS satellites in the sky compared to those provided by GPS alone, which would bring a considerable improvement in terms of satellite geometry at any location on the globe. Most of the research studies on the simultaneous use GPS and Galileo measurements, for example, have been carried out through signal simulation, by means of either software or hardware simulators. In order to analyze the impact of the larger number of available satellites, but using actual satellite signals, we have used a different technique in which the current GPS constellation is virtually doubled. This means that we are simulating a second GNSS system with the same orbital characteristics as GPS (but not considering any improved signal characteristics it may have) in different geometry condition - in effect, a doubling of the GPS constellation. The exact procedure is explained in this paper. The main advantages of this technique are that it does not require the use of a simulator; it is based on real satellite signals; and it is reasonably simple to perform if the appropriate positioning engine is available. Using this technique, we are able to analyze the possible impact of a second GNSS constellation. Although it is not possible to derive immutable numbers to quantify this improvement (a shared limitation of any other simulation analysis), due to the nature of the analysis technique, it is possible to have a reasonably clear idea of what the positioning performance will actually look like. Precise point positioning (PPP) is one of the existing techniques for determining point coordinates using a GPS receiver. In this technique

  11. Multi-point Magnetic Field Observations of Field-Aligned Currents from Swarm Constellation Mission

    NASA Astrophysics Data System (ADS)

    Le, Guan; Chi, Peter; Lühr, Hermann; Gjerloev, Jesper; Stolle, Claudia; Park, Jaeheung; Rauberg, Jan

    2015-04-01

    In this paper, we report the results of case studies of multi-point magnetic field measurements of field-aligned currents (FACs) from Swarm constellation mission to understand their temporal characteristics and hemispheric asymmetry. For science operations (since April, 2014), the three spacecraft were placed in slightly different polar orbits: Swarm B spacecraft in a higher altitude orbit (507km x 512km) and Swarm A and C side-by-side in lower altitude orbits (459km x 462km). In the beginning of the science operational phase, the longitudinal separations of the orbital planes were small, and Swarm A/C pair and Swarm B were nearly out of phase in the orbit. This unique orbit configuration provides opportunities to study some new features of FACs. Specifically, the Swarm satellites make multiple crossings of a FAC region within a few hours. Such data enable us to study temporal variations in several time scales, from 1 minute up to about 3 hours. Furthermore, the three satellites make nearly simultaneous observations of FACs in northern and southern hemispheres, which provide us an opportunity to study the hemispheric asymmetry.

  12. Evaluation of Quad-Constellation GNSS Precise Point Positioning in Egypt

    NASA Astrophysics Data System (ADS)

    El Manaily, Emad; Abd Rabbou, Mahmoud; El-Shazly, Adel; Baraka, Moustafa

    2017-03-01

    Commonly, relative GPS positioning technique is used in Egypt for precise positioning applications. However, the requirement of a reference station is usually problematic for some applications as it limits the operational range of the system and increases the system cost and complexity On the other hand; the single point positioning is traditionally used for low accuracy applications such as land vehicle navigation with positioning accuracy up to 10 meters in some scenarios which caused navigation problems especially in downtown areas. Recently, high positioning accuracy can be obtained through Precise Point Positioning (PPP) technique in which only once GNSS receiver is used. However, the major drawback of PPP is the long convergence time to reach to the surveying grade accuracy compared to the existing relative techniques. Moreover, the PPP accuracy is significantly degraded due to shortage in satellite availability in urban areas. To overcome these limitations, the quad constellation GNSS systems namely; GPS.GLONASS, Galileo and BeiDou can be combined to increase the satellite availability and enhance the satellite geometry which in turn reduces the convergence time. In Egypt, at the moment, the signals of both Galileo and BeiDou could be logged with limited number of satellites up to four and six satellites for both Systems respectively. In this paper, we investigated the performance of the Quad-GNSS positioning in both dual- and single-frequency ionosphere free PPP modes for both high accurate and low cost navigation application, respectively. The performance of the developed PPP models will be investigated through GNSS data sets collected at three Egyptian cities namely, Cairo, Alexandria and Aswan.

  13. Point pattern match-based change detection in a constellation of previously detected objects

    SciTech Connect

    Paglieroni, David W.

    2016-06-07

    A method and system is provided that applies attribute- and topology-based change detection to objects that were detected on previous scans of a medium. The attributes capture properties or characteristics of the previously detected objects, such as location, time of detection, detection strength, size, elongation, orientation, etc. The locations define a three-dimensional network topology forming a constellation of previously detected objects. The change detection system stores attributes of the previously detected objects in a constellation database. The change detection system detects changes by comparing the attributes and topological consistency of newly detected objects encountered during a new scan of the medium to previously detected objects in the constellation database. The change detection system may receive the attributes of the newly detected objects as the objects are detected by an object detection system in real time.

  14. Precise Point Positioning Model Using Triple GNSS Constellations: GPS, Galileo and BeiDou

    NASA Astrophysics Data System (ADS)

    Afifi, Akram; El-Rabbany, Ahmed

    2016-12-01

    This paper introduces a comparison between dual-frequency precise point positioning (PPP) post-processing model, which combines the observations of three different GNSS constellations, namely GPS, Galileo, and BeiDou and real-time PPP model. A drawback of a single GNSS system such as GPS, however, is the availability of sufficient number of visible satellites in urban areas. Combining GNSS observations offers more visible satellites to users, which in turn is expected to enhance the satellite geometry and the overall positioning solution. However, combining several GNSS observables introduces additional biases, which require rigorous modelling, including the GNSS time offsets and hardware delays. In this paper, a GNSS post-processing PPPP model is developed using ionosphere-free linear combination. The additional biases of the GPS, Galileo, and BeiDou combination are accounted for through the introduction of a new unknown parameter, which is identified as the inter-system bias, in the PPP mathematical model. Natural Resources Canada's GPSPace PPP software is modified to enable a combined GPS / Galileo / BeiDou PPP solution and to handle the newly inter-system bias. A total of four data sets at four IGS stations are processed to verify the developed PPP model. Precise satellite orbit and clock products from the IGS-MGEX network are used to correct of the GPS, Galileo and BeiDou measurements. For the real-time PPP model the corrections of the satellites orbit and clock are obtained through the international GNSS service (IGS) real-time service (RTS). GPS and Galileo Observations are used for the GNSS RTS-IGS PPP model as the RTS-IGS satellite products are not available for BeiDou satellites. This paper provides the GNSS RTS-IGS PPP model using different satellite clock corrections namely: IGS01, IGC01, IGS01, and IGS03. All PPP models results of convergence time and positioning precision are compared to the traditional GPS-only PPP model. It is shown that combining

  15. 3-Dimensional Necklace Flower Constellations

    NASA Astrophysics Data System (ADS)

    Arnas, David; Casanova, Daniel; Tresaco, Eva; Mortari, Daniele

    2017-09-01

    A new approach in satellite constellation design is presented in this paper, taking as a base the 3D Lattice Flower Constellation Theory and introducing the necklace problem in its formulation. This creates a further generalization of the Flower Constellation Theory, increasing the possibilities of constellation distribution while maintaining the characteristic symmetries of the original theory in the design.

  16. A closed-form method for single-point positioning with six satellites in dual-GNSS constellations

    NASA Astrophysics Data System (ADS)

    Teng, Yunlong; Huang, Qi; Ao, Yongcai; Li, Yun

    2016-12-01

    With the impact of the Global Navigation Satellite System (GNSS), dual-GNSS constellations are playing an increasingly significant role in positioning, navigation and timing (PNT) applications. Aiming at improving from the existing method, i.e., linearization, of solving the single-point positioning problem under a dual-GNSS, this paper develops a closed-form method for solving PNT problems in the case of six satellites. This method reduces the positioning problem to a simple mathematical problem of finding solutions to a quadratic equation, thereby needing only one receiver clock bias (RCB) as variable. By solving the RCB, the positioning information in three dimensions is obtained by utilizing a linear equation. Compared with the existing method, the closed-form method requires no initial position or iterations. This method thus provides a direct solution to single-point positioning. Further, how to check the uniqueness and the validity of the solutions is also derived. Experimental results verify the validity, applicability and efficiency of the proposed method.

  17. Tethered constellations

    NASA Technical Reports Server (NTRS)

    Lorenzini, E.

    1986-01-01

    The studies that have been carried out on Tethered Constellations are briefly addressed. A definition of a tethered constellation is any number of masses/platforms greater that two connected by tethers in a stable configuration. Configurations and stability constraints are reviewed. Conclusions reached are: (1) The 1-D, horizontal, passively stabilized constellations have been ruled out; (2) Fishbone constellations have been also ruled out; (3) Alternative stable 2-D configurations have been devised such as the quadrangular configuration stabilized by electrodynamic forces (ESC), the quadrangular configuration stabilized by differential air drag (DSC), and the pseudo elliptical configuration stabilized by electrodynamic forces (PEC). Typical dimensions for these constellations are 10 km (horizontal) by 20 km (vertical) with balloon diameters around 100 m in the case of a DSC and a power consumption around 7 KW for an ESC or PEC.

  18. Crater Constellation

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    (the Cup; abbrev. Crt, gen. Crateris; area 282 sq. deg.) A southern constellation which lies to the south-west of Virgo, and culminates at midnight in mid-March. It represents the cup of the god Apollo in Greek mythology (see Corvus). Its brightest stars were cataloged by Ptolemy (c. AD 100-175) in the Almagest....

  19. Egyptian Constellations

    NASA Astrophysics Data System (ADS)

    Lull, José; Belmonte, Juan Antonio

    The ancient Egyptians had a wide range of constellations, which populated the skies of ancient Egypt (see Chap. 133, "Orientation of Egyptian Temples: An Overview", 10.1007/978-1-4614-6141-8_146) for more than three millennia, whose knowledge has come to us through lists of stars and other representations which have mainly appeared in a dozen of coffins, a few clepsydrae, and a good set of astronomical ceilings. Hence, by making very simple assumptions and using the information provided by the ancient Egyptian sky-watchers, it is possible to uncover a great part of the ancient Egyptian firmament. This celestial tapestry was populated by the images of animals, symbols, and divinities that were most significant in understanding the Egyptian interpretation of the cosmos.

  20. Origins of the Human Pointing Gesture: A Training Study

    ERIC Educational Resources Information Center

    Matthews, Danielle; Behne, Tanya; Lieven, Elena; Tomasello, Michael

    2012-01-01

    Despite its importance in the development of children's skills of social cognition and communication, very little is known about the ontogenetic origins of the pointing gesture. We report a training study in which mothers gave children one month of extra daily experience with pointing as compared with a control group who had extra experience with…

  1. Origins of the Human Pointing Gesture: A Training Study

    ERIC Educational Resources Information Center

    Matthews, Danielle; Behne, Tanya; Lieven, Elena; Tomasello, Michael

    2012-01-01

    Despite its importance in the development of children's skills of social cognition and communication, very little is known about the ontogenetic origins of the pointing gesture. We report a training study in which mothers gave children one month of extra daily experience with pointing as compared with a control group who had extra experience with…

  2. Methods and apparatuses for signaling with geometric constellations

    NASA Technical Reports Server (NTRS)

    Barsoum, Maged F. (Inventor); Jones, Christopher R. (Inventor)

    2012-01-01

    Communication systems are described that use signal constellations, which have unequally spaced (i.e. geometrically shaped) points. In many embodiments, the communication systems use specific geometric constellations that are capacity optimized at a specific SNR. In addition, ranges within which the constellation points of a capacity optimized constellation can be perturbed and are still likely to achieve a given percentage of the optimal capacity increase compared to a constellation that maximizes d.sub.min, are also described. Capacity measures that are used in the selection of the location of constellation points include, but are not limited to, parallel decode (PD) capacity and joint capacity.

  3. Sattelite-Constellation Design

    NASA Technical Reports Server (NTRS)

    Lo, M.

    1999-01-01

    The importance of communications satellite constellations cannot be overstated. In one fell swoop, such a constellation can provide an under developed region without a modern communication infrastructure with an instant modern communications network.

  4. 48 CFR 52.247-46 - Shipping Point(s) Used in Evaluation of F.o.b. Origin Offers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 2 2013-10-01 2013-10-01 false Shipping Point(s) Used in... Text of Provisions and Clauses 52.247-46 Shipping Point(s) Used in Evaluation of F.o.b. Origin Offers... when price evaluation for shipments from various shipping points is contemplated: Shipping Point(s...

  5. 48 CFR 52.247-46 - Shipping Point(s) Used in Evaluation of F.o.b. Origin Offers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 2 2012-10-01 2012-10-01 false Shipping Point(s) Used in... Text of Provisions and Clauses 52.247-46 Shipping Point(s) Used in Evaluation of F.o.b. Origin Offers... when price evaluation for shipments from various shipping points is contemplated: Shipping Point(s...

  6. 48 CFR 52.247-46 - Shipping Point(s) Used in Evaluation of F.o.b. Origin Offers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 2 2014-10-01 2014-10-01 false Shipping Point(s) Used in... Text of Provisions and Clauses 52.247-46 Shipping Point(s) Used in Evaluation of F.o.b. Origin Offers... when price evaluation for shipments from various shipping points is contemplated: Shipping Point(s...

  7. Improving the point of origin determination in bloodstain pattern analysis.

    PubMed

    de Bruin, Karla G; Stoel, Reinoud D; Limborgh, Josita C M

    2011-11-01

    In bloodstain pattern analysis, it is important to know the point of origin (PO) of an impact pattern. This point can be estimated by means of the stringing method, the tangent method, or by commercially available computer programs. In this study, the accuracy of two computer programs was investigated under different conditions. Impact patterns were created by means of a modified mouse trap, and subsequently the PO was calculated. By examining the characteristics of single bloodstains, the influence on the deviation could be determined. To improve the estimation of the PO, it is important to select bloodstains that lie close to the presumable location of the blood source, that are large (width >1.5 mm) and that show an elliptical form. If possible, bloodstains from different walls should be taken into account. Our recommendations may improve the PO determination of impact patterns. © 2011 American Academy of Forensic Sciences.

  8. The Magentospheric Multiscale Constellation

    NASA Technical Reports Server (NTRS)

    Tooley, C. R.; Black, R. K.; Robertson, B. P.; Stone, J. M.; Pope, S. E.; Davis, G. T.

    2015-01-01

    The Magnetospheric Multiscale (MMS) mission is the fourth mission of the Solar Terrestrial Probe (STP) program of the National Aeronautics and Space Administration (NASA). The MMS mission was launched on March 12, 2015. The MMS mission consists of four identically instrumented spin-stabilized observatories which are flown in formation to perform the first definitive study of magnetic reconnection in space. The MMS mission was presented with numerous technical challenges, including the simultaneous construction and launch of four identical large spacecraft with 100 instruments total, stringent electromagnetic cleanliness requirements, closed-loop precision maneuvering and pointing of spinning flexible spacecraft, on-board GPS based orbit determination far above the GPS constellation, and a flight dynamics design that enables formation flying with separation distances as small as 10 km. This paper describes the overall mission design and presents an overview of the design, testing, and early on-orbit operation of the spacecraft systems and instrument suite.

  9. The Magnetospheric Multiscale Constellation

    NASA Astrophysics Data System (ADS)

    Tooley, C. R.; Black, R. K.; Robertson, B. P.; Stone, J. M.; Pope, S. E.; Davis, G. T.

    2016-03-01

    The Magnetospheric Multiscale (MMS) mission is the fourth mission of the Solar Terrestrial Probe (STP) program of the National Aeronautics and Space Administration (NASA). The MMS mission was launched on March 12, 2015. The MMS mission consists of four identically instrumented spin-stabilized observatories which are flown in formation to perform the first definitive study of magnetic reconnection in space. The MMS mission was presented with numerous technical challenges, including the simultaneous construction and launch of four identical large spacecraft with 100 instruments total, stringent electromagnetic cleanliness requirements, closed-loop precision maneuvering and pointing of spinning flexible spacecraft, on-board GPS based orbit determination far above the GPS constellation, and a flight dynamics design that enables formation flying with separation distances as small as 10 km. This paper describes the overall mission design and presents an overview of the design, testing, and early on-orbit operation of the spacecraft systems and instrument suite.

  10. The Magentospheric Multiscale Constellation

    NASA Technical Reports Server (NTRS)

    Tooley, C. R.; Black, R. K.; Robertson, B. P.; Stone, J. M.; Pope, S. E.; Davis, G. T.

    2015-01-01

    The Magnetospheric Multiscale (MMS) mission is the fourth mission of the Solar Terrestrial Probe (STP) program of the National Aeronautics and Space Administration (NASA). The MMS mission was launched on March 12, 2015. The MMS mission consists of four identically instrumented spin-stabilized observatories which are flown in formation to perform the first definitive study of magnetic reconnection in space. The MMS mission was presented with numerous technical challenges, including the simultaneous construction and launch of four identical large spacecraft with 100 instruments total, stringent electromagnetic cleanliness requirements, closed-loop precision maneuvering and pointing of spinning flexible spacecraft, on-board GPS based orbit determination far above the GPS constellation, and a flight dynamics design that enables formation flying with separation distances as small as 10 km. This paper describes the overall mission design and presents an overview of the design, testing, and early on-orbit operation of the spacecraft systems and instrument suite.

  11. The Magnetospheric Multiscale Constellation

    NASA Technical Reports Server (NTRS)

    Tooley, C. R.; Black, R. K.; Robertson, B. P.; Stone, J. M.; Pope, S. E.; Davis, G. T.

    2015-01-01

    The Magnetospheric Multiscale (MMS) mission is the fourth mission of the Solar Terrestrial Probe (STP) program of the National Aeronautics and Space Administration (NASA). The MMS mission was launched on March 12, 2015. The MMS mission consists of four identically instrumented spin-stabilized observatories which are flown in formation to perform the first definitive study of magnetic reconnection in space. The MMS mission was presented with numerous technical challenges, including the simultaneous construction and launch of four identical large spacecraft with 100 instruments total, stringent electromagnetic cleanliness requirements, closed-loop precision maneuvering and pointing of spinning flexible spacecraft, on-board GPS based orbit determination far above the GPS constellation, and a flight dynamics design that enables formation flying with separation distances as small as 10 km. This paper describes the overall mission design and presents an overview of the design, testing, and early on-orbit operation of the spacecraft systems and instrument suite.

  12. The Solar system.Stars and constellations

    NASA Astrophysics Data System (ADS)

    Horia Minda, Octavian

    2017-04-01

    It is important for students to understand what is in our Solar System. The Students need to know that there are other things besides the Earth, Sun and Moon in the solar sky. The students will learn about the other eight planets and a few other celestial objects like stars and constellations. Constellations are useful because they can help people to recognize stars in the sky. By looking for patterns, the stars and locations can be much easier to spot. The constellations had uses in ancient times. They were used to help keep track of the calendar. This was very important so that people knew when to plant and harvest crops. Another important use for constellations was navigation. By finding Ursa Minor it is fairly easy to spot the North Star (Polaris). Using the height of the North Star in the sky, navigators could figure out their latitude helping ships to travel across the oceans. Objective: 1. The students will be introduced to the origin of the stars they see at night. 2. They will learn that there are groups of stars called constellations. The students will individually create their own constellations. They will be given the chance to tell the class a small story explaining their constellation. Evaluation of Children: The children will be evaluated through the creation of their constellations and ability to work in groups on the computers.

  13. Capacity Maximizing Constellations

    NASA Technical Reports Server (NTRS)

    Barsoum, Maged; Jones, Christopher

    2010-01-01

    Some non-traditional signal constellations have been proposed for transmission of data over the Additive White Gaussian Noise (AWGN) channel using such channel-capacity-approaching codes as low-density parity-check (LDPC) or turbo codes. Computational simulations have shown performance gains of more than 1 dB over traditional constellations. These gains could be translated to bandwidth- efficient communications, variously, over longer distances, using less power, or using smaller antennas. The proposed constellations have been used in a bit-interleaved coded modulation system employing state-ofthe-art LDPC codes. In computational simulations, these constellations were shown to afford performance gains over traditional constellations as predicted by the gap between the parallel decoding capacity of the constellations and the Gaussian capacity

  14. Mega-constellations Issues

    NASA Astrophysics Data System (ADS)

    Bastida Virgili, Benjamin; Krag, Holger

    2016-07-01

    Space traffic has always been subject to considerable fluctuations. In the past, these fluctuations have been mainly driven by geopolitical and economic factors. During the last years there has been a considerable increase due to the use of cubesats by non-traditional space operators, and due to a significant change of mission scopes and mission orbits in Low Earth Orbit (LEO). In the near future, however, many indications point to a further increase in the space traffic in LEO. This increase is mainly driven by a cheaper access to space, also triggered by the miniaturisation of spacecraft systems. An acceleration of this trend is expressed by the announcement of large constellations in LEO with the purpose to provide broadband internet communication, allowing to minimise the required infrastructure on Earth. The number of artificial objects in orbit continues to increase and, with it, a key threat to space sustainability. In response, space agencies have identified a set of mitigation guidelines aimed at enabling space users to reduce the generation of space debris by, for example, limiting the orbital lifetime of their spacecraft and of launcher stages after the end of their mission to 25 years in LEO. However, several recent studies have shown that, today, current guidelines for the LEO protected zone are insufficiently applied by space systems of all sizes. Under these conditions, a step increase in the launch rate is a potential concern for the environment, in particular if the current End of Life (EOL) behaviour prevails in the future. Even in a perfect behaviour w.r.t. the 25 year lifetime rule, the new traffic might lead to unrecoverable environment trends. Furthermore, the requirement for reliability of the disposal function is of 90%, however, weighted with the reliability of the entire system. A failure rate of 10%, in general, was found to be acceptable under current space traffic conditions. This might not be sustainable when the LEO launch rates

  15. 48 CFR 52.247-46 - Shipping Point(s) Used in Evaluation of F.o.b. Origin Offers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Evaluation of F.o.b. Origin Offers. 52.247-46 Section 52.247-46 Federal Acquisition Regulations System... Text of Provisions and Clauses 52.247-46 Shipping Point(s) Used in Evaluation of F.o.b. Origin Offers. As prescribed in 47.305-3(b)(4)(ii), insert the following provision in f.o.b. origin...

  16. 48 CFR 52.247-46 - Shipping Point(s) Used in Evaluation of F.o.b. Origin Offers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Evaluation of F.o.b. Origin Offers. 52.247-46 Section 52.247-46 Federal Acquisition Regulations System... Text of Provisions and Clauses 52.247-46 Shipping Point(s) Used in Evaluation of F.o.b. Origin Offers. As prescribed in 47.305-3(b)(4)(ii), insert the following provision in f.o.b. origin...

  17. Constellation Program Press Conference

    NASA Image and Video Library

    2006-06-04

    NASA Administrator Michael Griffin, left, Scott Horowitz, NASA Associate Administrator for Exploration Systems and Jeff Hanley, Constellation Program Manager, right, are seen during a press conference outlining specific center responsibilities associated with the Constellation Program for robotic and human Moon and Mars exploration, Monday, June 5, 2006, at NASA Headquarters in Washington. Photo Credit (NASA/Bill Ingalls)

  18. Constellation Program Press Conference

    NASA Image and Video Library

    2006-06-04

    Scott Horowitz, NASA Associate Administrator for Exploration Systems, center, speaks as Jeff Hanley, Constellation Program Manager, right, looks on during a press conference outlining specific center responsibilities associated with the Constellation Program for robotic and human Moon and Mars exploration, Monday, June 5, 2006, at NASA Headquarters in Washington. Photo Credit (NASA/Bill Ingalls)

  19. Constellation Program Update

    NASA Image and Video Library

    2006-06-05

    Jeff Hanley, Constellation Program Manager, right, and Scott J. Horowitz, NASA Associate Administrator for Exploration Systems announce to NASA employees and members of the media the responsibilities of the NASA centers associated with the Constellation Program for robotic and human Moon and Mars exploration on Wednesday, June 5, 2006, at NASA Headquarters in Washington. Photo Credit: (NASA/Bill Ingalls)

  20. Constellation Program Update

    NASA Image and Video Library

    2006-06-04

    Jeff Hanley, Constellation Program Manager, right, listens to a question during a NASA Update outlining responsibilities of the NASA centers associated with the Constellation Program for robotic and human Moon and Mars exploration on Wednesday, June 5, 2006, at NASA Headquarters in Washington. Photo Credit: (NASA/Bill Ingalls)

  1. Constellation Program Press Conference

    NASA Image and Video Library

    2006-06-04

    Jeff Hanley, Constellation Program Manager, speaks during a press conference outlining specific center responsibilities associated with the Constellation Program for robotic and human Moon and Mars exploration, Monday, June 5, 2006, at NASA Headquarters in Washington. Photo Credit (NASA/Bill Ingalls)

  2. Constellation Program Press Conference

    NASA Image and Video Library

    2006-06-04

    Dean Acosta, NASA Deputy Assistant Administrator and Press Secretary, moderates a press conference with NASA Administrator Michael Griffin Scott Horowitz, NASA Associate Administrator for Exploration Systems and Jeff Hanley, Constellation Program Manager, outlining specific center responsibilities associated with the Constellation Program for robotic and human Moon and Mars exploration, Monday, June 5, 2006, at NASA Headquarters in Washington. Photo Credit (NASA/Bill Ingalls)

  3. Constellation Program Press Conference

    NASA Image and Video Library

    2006-06-04

    Scott Horowitz, NASA Associate Administrator for Exploration Systems, left, looks on as Jeff Hanley, Constellation Program Manager, speaks during a press conference outlining specific center responsibilities associated with the Constellation Program for robotic and human Moon and Mars exploration, Monday, June 5, 2006, at NASA Headquarters in Washington. Photo Credit (NASA/Bill Ingalls)

  4. Constellation Program Update

    NASA Image and Video Library

    2006-06-04

    Scott J. Horowitz, NASA Associate Administrator for Exploration Systems, left, and Jeff Hanley, Constellation Program Manager, announce to NASA employees and members of the media the responsibilities of the NASA centers associated with the Constellation Program for robotic and human Moon and Mars exploration on Wednesday, June 5, 2006, at NASA Headquarters in Washington. Photo Credit: (NASA/Bill Ingalls)

  5. Constellation Program Update

    NASA Image and Video Library

    2006-06-04

    Jeff Hanley, Constellation Program Manager, announces to NASA employees and members of the media the responsibilities of the NASA centers associated with the Constellation Program for robotic and human Moon and Mars exploration on Wednesday, June 5, 2006, at NASA Headquarters in Washington. Photo Credit: (NASA/Bill Ingalls)

  6. Constellation Program Press Conference

    NASA Image and Video Library

    2006-06-04

    Members of the media listen during a press conference with NASA Administrator Michael Griffin, Scott Horowitz, NASA Associate Administrator for Exploration Systems and Jeff Hanley, Constellation Program Manager, outlining specific center responsibilities associated with the Constellation Program for robotic and human Moon and Mars exploration, Monday, June 5, 2006, at NASA Headquarters in Washington. Photo Credit (NASA/Bill Ingalls)

  7. Constellation Program Press Conference

    NASA Image and Video Library

    2006-06-04

    Scott Horowitz, NASA Associate Administrator for Exploration Systems, left, and Jeff Hanley, Constellation Program Manager, are seen during a press conference outlining specific center responsibilities associated with the Constellation Program for robotic and human Moon and Mars exploration, Monday, June 5, 2006, at NASA Headquarters in Washington. Photo Credit (NASA/Bill Ingalls)

  8. GPM Constellation with Clock

    NASA Image and Video Library

    In this animation the orbit paths of the NASA partner satellites of the GPM constellation fill in blue as the instruments pass over Earth. Rainfall appears light blue for light rain, yellow for mod...

  9. Constellation Program Update

    NASA Image and Video Library

    2006-06-04

    NASA Administrator Michael Griffin, left, announces to NASA employees and members of the media the responsibilities of the NASA centers associated with the Constellation Program for robotic and human Moon and Mars exploration on Wednesday, June 5, 2006, at NASA Headquarters in Washington. He is joined by Scott J. Horowitz, NASA Associate Administrator for Exploration Systems and Jeff Hanley, Constellation Program Manager, right. Photo Credit: (NASA/Bill Ingalls)

  10. Constellation Program Update

    NASA Image and Video Library

    2006-06-04

    NASA Administrator Michael Griffin, left, Scott J. Horowitz, NASA Associate Administrator for Exploration Systems and Jeff Hanley, Constellation Program Manager, right, announce to NASA employees and members of the media the responsibilities of the NASA centers associated with the Constellation Program for robotic and human Moon and Mars exploration on Wednesday, June 5, 2006, at NASA Headquarters in Washington. Photo Credit: (NASA/Bill Ingalls)

  11. Constellation Program Press Conference

    NASA Image and Video Library

    2006-06-04

    NASA Administrator Michael Griffin, seated left, Scott Horowitz, NASA Associate Administrator for Exploration Systems and Jeff Hanley, Constellation Program Manager, right, are seen during a press conference outlining specific center responsibilities associated with the Constellation Program for robotic and human moon and Mars exploration, Monday, June 5, 2006, at NASA Headquarters in Washington. Dean Acosta, NASA Deputy Assistant Administrator and Press Secretary, far left, moderates the program. Photo Credit (NASA/Bill Ingalls)

  12. Constellation Program Update

    NASA Image and Video Library

    2006-06-04

    Jeff Hanley, Constellation Program Manager, right, announces to NASA employees and members of the media the responsibilities of the NASA centers associated with the Constellation Program for robotic and human Moon and Mars exploration on Wednesday, June 5, 2006, at NASA Headquarters in Washington. Hanley is joined by Scott J. Horowitz, NASA Associate Administrator for Exploration Systems and NASA Administrator Michael Griffin, left. Photo Credit: (NASA/Bill Ingalls)

  13. Constellation Program Update

    NASA Image and Video Library

    2006-06-04

    Scott J. Horowitz, NASA Associate Administrator for Exploration Systems, center, announces to NASA employees and members of the media the responsibilities of the NASA centers associated with the Constellation Program for robotic and human Moon and Mars exploration on Wednesday, June 5, 2006, at NASA Headquarters in Washington. Horowitz was joined by NASA Administrator Michael Griffin, left, and Jeff Hanley, Constellation Program Manager. Photo Credit: (NASA/Bill Ingalls)

  14. Macedonian Folk Constellations

    NASA Astrophysics Data System (ADS)

    Cenev, G.

    2008-10-01

    Ethno-astronomical researches started to be performed on the territory of the Republic of Macedonia in 1982 and since then they are constantly carried out. Information gathered directly from the elderly inhabitants of around 130 villages all over the country, enlighten the folk presentation of sky, division of the stars and constellations, but also provided a vast scope of myths, beliefs and rituals linked to the sky, stars, and constellations. More in-depth analyses of the gathered data lead to the reconstruction of the ancient stars map of the Macedonian people. Due to the fact that in the past people recognized only two seasons, most of the stars and constellations are presented on the so-called winter and summer sky. People were also familiar with the part of the sky around the Polaris and knew about the constellations that did not rise and set, but are special part of the folk sky map. The mentioned study provides a comparative analysis of the folk constellations known among the Macedonian people and folk constellations know among the others, mos tly neighbouring people living on the Balkan Peninsula.

  15. The BRITE Nanosatellite Constellation Mission

    NASA Astrophysics Data System (ADS)

    Schwarzenberg-Czerny, Alexander; Weiss, Werner; Moffat, Anthony; Zee, Robert E.; Rucinski, Slavek; Mochnacki, Stefan; Matthews, Jaymie; Breger, Michel; Kuschnig, Rainer; Koudelka, Otto; Orleanski, Piotr; Pamyatnykh, Alexei; Pigulski, Andrzej; Grant, Cordell

    BRITE Constellation, short for "BRIght Target Explorer Constellation," is a group of six seven-kilogram nanosatellites from Austria, Poland and Canada carrying three-centimeter aperture optical telescopes. The purpose of the mission is to photometrically measure low-level oscilla-tions and temperature variations in the sky's 286 stars brighter than visual magnitude 3.5, with unprecedented precision and time sampling not achievable through terrestrial-based methods. These stars turn out, for the most part, to be among the most luminous -either massive stars during their whole lifetimes or medium-mass stars at the very end of their nuclear burning phases. Such stars dominate the ecology of the Universe and the current massive ones are believed to represent the lower mass-range of the first stars ever formed (although long gone from the local Universe). Astronomers are eager to measure the variable behavior of lumi-nous stars in order to explore their inner workings in a unique way. BRITE Constellation will investigate the role that stellar winds play in setting up future stellar life cycles, and will measure pulsations to probe the histories and ages of luminous stars through asteroseismology. The three-axis pointing performance (1 arcminute RMS stability) of each BRITE satellite is a significant advancement by the University of Toronto's Space Flight Laboratory over any-thing that has ever flown before on a nanosatellite, and is a critical element that enables the high precision photometry mission. The University of Vienna and FFG/ALR (Austria's space agency) are financing the development of two satellites and development is nearing completion. The Polish Academy of Sciences is preparing two additional satellites. The Canadian Space Agency is also expected to fund two satellites in the constellation. This paper will summarize the science objectives of the mission and describe the progress to date.

  16. Methods and Apparatuses for Signaling with Geometric Constellations in a Raleigh Fading Channel

    NASA Technical Reports Server (NTRS)

    Barsoum, Maged F. (Inventor); Jones, Christopher R. (Inventor)

    2017-01-01

    Communication systems are described that use signal constellations, which have unequally spaced (i.e. `geometrically` shaped) points. In many embodiments, the communication systems use specific geometric constellations that are capacity optimized at a specific SNR, over the Raleigh fading channel. In addition, ranges within which the constellation points of a capacity optimized constellation can be perturbed and are still likely to achieve a given percentage of the optimal capacity increase compared to a constellation that maximizes d.sub.min, are also described. Capacity measures that are used in the selection of the location of constellation points include, but are not limited to, parallel decode (PD) capacity and joint capacity.

  17. On the origin of planetary-scale tipping points.

    PubMed

    Lenton, Timothy M; Williams, Hywel T P

    2013-07-01

    Tipping points are recognised in many systems, including ecosystems and elements of the climate system. But can the biosphere as a whole tip and, if so, how? Past global tipping points were rare and occurred in the coupled planetary-scale dynamics of the Earth system, not in the local-scale dynamics of its weakly interacting component ecosystems. Yet, evolutionary innovations have triggered past global transformations, suggesting that tipping point theory needs to go beyond bifurcations and networks to include evolution. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Flower Constellations as rigid objects in space

    NASA Astrophysics Data System (ADS)

    Mortari, Daniele

    2006-08-01

    This paper summarizes the findings and the research status on Flower Constellations, a novel and revolutionary way to design satellite constellations that has been discovered and proposed at Texas A&M University. The theory of Flower Constellations is a natural consequence of the theory of compatible (or resonant) orbits. The most surprising aspect of the Flower Constellations is that the satellite distribution identifies the edges of rotating figures whose shapes are time invariant. The complex synchronized dynamics of the satellites preserves the shape of a space object. The whole Flower Constellation is an axial-symmetric rigid object in space that is spinning with prescribed angular velocity. The shape of this object can be deformed by playing with the Flower Constellation design parameters, and the object's axis of symmetry can be set to point to any inertial direction. In particular, when the axis of symmetry is aligned with the Earth's spin axis, the J2 linear-dominant effect is identical for all the orbits. In this case, the J2 effect deforms the object shape while preserving the axial-symmetry.

  19. Constellation modulation - an approach to increase spectral efficiency.

    PubMed

    Dash, Soumya Sunder; Pythoud, Frederic; Hillerkuss, David; Baeuerle, Benedikt; Josten, Arne; Leuchtmann, Pascal; Leuthold, Juerg

    2017-07-10

    Constellation modulation (CM) is introduced as a new degree of freedom to increase the spectral efficiency and to further approach the Shannon limit. Constellation modulation is the art of encoding information not only in the symbols within a constellation but also by encoding information by selecting a constellation from a set of constellations that are switched from time to time. The set of constellations is not limited to sets of partitions from a given constellation but can e.g., be obtained from an existing constellation by applying geometrical transformations such as rotations, translations, scaling, or even more abstract transformations. The architecture of the transmitter and the receiver allows for constellation modulation to be used on top of existing modulations with little penalties on the bit-error ratio (BER) or on the required signal-to-noise ratio (SNR). The spectral bandwidth used by this modulation scheme is identical to the original modulation. Simulations demonstrate a particular advantage of the scheme for low SNR situations. So, for instance, it is demonstrated by simulation that a spectral efficiency increases by up to 33% and 20% can be obtained at a BER of 10(-3) and 2×10(-2) for a regular BPSK modulation format, respectively. Applying constellation modulation, we derive a most power efficient 4D-CM-BPSK modulation format that provides a spectral efficiency of 0.7 bit/s/Hz for an SNR of 0.2 dB at a BER of 2 × 10(-2).

  20. Ancient Chinese constellations

    NASA Astrophysics Data System (ADS)

    Xu, Junjun

    2011-06-01

    China, a country with a long history and a specific culture, has also a long and specific astronomy. Ancient Chinese astronomers observed the stars, named and distributed them into constellations in a very specific way, which is quite different from the current one. Around the Zodiac, stars are divided into four big regions corresponding with the four orientations, and each is related to a totem, either the Azure Dragon, the Vermilion Bird, the White Tiger or the Murky Warrior. We present a general pattern of the ancient Chinese constellations, including the four totems, their stars and their names.

  1. Constellation Program Update

    NASA Image and Video Library

    2006-06-04

    NASA Administrator Michael Griffin is seen through a television camera at a NASA Update announcing to NASA employees and members of the media the responsibilities of the NASA centers associated with the Constellation Program for robotic and human Moon and Mars exploration on Wednesday, June 5, 2006, at NASA Headquarters in Washington. Griffin was joined by Scott J. Horowitz, NASA Associate Administrator for Exploration Systems and Jeff Hanley, Constellation Program Manager, right. Dean Acosta, NASA Deputy Assistant Administrator and Press Secretary, far left, moderates the program. Photo Credit: (NASA/Bill Ingalls)

  2. Coastal geology and recent origins for Sand Point, Lake Superior

    USGS Publications Warehouse

    Fisher, Timothy G.; Krantz, David E.; Castaneda, Mario R.; Loope, Walter L.; Jol, Harry M.; Goble, Ronald J.; Higley, Melinda C.; DeWald, Samantha; Hansen, Paul

    2014-01-01

    Sand Point is a small cuspate foreland located along the southeastern shore of Lake Superior within Pictured Rocks National Lakeshore near Munising, Michigan. Park managers’ concerns for the integrity of historic buildings at the northern periphery of the point during the rising lake levels in the mid-1980s greatly elevated the priority of research into the geomorphic history and age of Sand Point. To pursue this priority, we recovered sediment cores from four ponds on Sand Point, assessed subsurface stratigraphy onshore and offshore using geophysical techniques, and interpreted the chronology of events using radiocarbon and luminescence dating. Sand Point formed at the southwest edge of a subaqueous platform whose base is probably constructed of glacial diamicton and outwash. During the post-glacial Nipissing Transgression, the base was mantled with sand derived from erosion of adjacent sandstone cliffs. An aerial photograph time sequence, 1939–present, shows that the periphery of the platform has evolved considerably during historical time, infl uenced by transport of sediment into adjacent South Bay. Shallow seismic refl ections suggest slump blocks along the leading edge of the platform. Light detection and ranging (LiDAR) and shallow seismic refl ections to the northwest of the platform reveal large sand waves within a deep (12 m) channel produced by currents fl owing episodically to the northeast into Lake Superior. Ground-penetrating radar profi les show transport and deposition of sand across the upper surface of the platform. Basal radiocarbon dates from ponds between subaerial beach ridges range in age from 540 to 910 cal yr B.P., suggesting that Sand Point became emergent during the last ~1000 years, upon the separation of Lake Superior from Lakes Huron and Michigan. However, optically stimulated luminescence (OSL) ages from the beach ridges were two to three times as old as the radiocarbon ages, implying that emergence of Sand Point may have begun

  3. CarbonSat Constellation

    NASA Astrophysics Data System (ADS)

    Sun, Wei; Tobehn, Carsten; Ernst, Robert; Bovensmann, Heinrich; Buchwitz, Michael; Burrows, John P.; Notholt, John

    1 Carbon dioxide (CO2) and methane (CH4) are the most important manmade greenhouse gases (GHGs) which are driving global climate change. Currently, the CO2 measurements from the ground observing network are still the main sources of information but due to the limited number of measurement stations the coverage is limited. In addition, CO2 monitoring and trading is often based mainly on bottom-up calculations and an independent top down verification is limited due to the lack of global measurement data with local resolution. The first CO2 and CH4 mapping from SCIAMACHY on ENVISAT shows that satellites add important missing global information. Current GHG measurement satellites (GOSAT)are limited either in spatial or temporal resolution and coverage. These systems have to collect data over a year or even longer to produce global regional fluxes products. Conse-quently global, timely, higher spatial resolution and high accuracy measurement are required for: 1. A good understanding of the CO2 and CH4 sources and sinks for reliable climate predic-tion; and 2. Independent and transparent verification of accountable sources and sinks in supporting Kyoto and upcoming protocols The CarbonSat constellation idea comes out the trade off of resolution and swath width during CarbonSat mission definition studies. In response to the urgent need to support the Kyoto and upcoming protocols, a feasibility study has been carried out. The proposed solution is a constellation of five CarbonSat satellites in 614km LTAN 13:00, which is able to provide global, daily CO2 and CH4 measurement everywhere on the Earth with high spatial resolution 2 × 2 km and low uncertainty lt;2ppm (CO2) and lt;8ppb (CH4). The unique global daily measurement capability significantly increases the number of cloud free measurements, which enables more reliable services associated with reduced uncertainty, e.g. to 0.15ppm (CO2) per month in 10km and even more timely products. The CarbonSat Constellation in

  4. Origin of acoustic emission produced during single point machining

    NASA Astrophysics Data System (ADS)

    Heiple, C. R.; Carpenter, S. H.; Armentrout, D. L.

    1991-05-01

    Acoustic emission was monitored during single point, continuous machining of 4340 steel and Ti-6Al-4V as a function of heat treatment. Acoustic emission produced during tensile and compressive deformation of these alloys has been previously characterized as a function of heat treatment. Heat treatments which increase the strength of 4340 steel increase the amount of acoustic emission produced during deformation, while heat treatments which increase the strength of Ti-6Al-4V decrease the amount of acoustic emission produced during deformation. If chip deformation were the primary source of acoustic emission during single point machining, then opposite trends in the level of acoustic emission produced during machining as a function of material strength would be expected for these two alloys. Trends in rms acoustic emission level with increasing strength were similar for both alloys, demonstrating that chip deformation is not a major source of acoustic emission in single point machining. Acoustic emission has also been monitored as a function of machining parameters on 6061-T6 aluminum, 304 stainless steel, 17-4PH stainless steel, lead, and teflon. The data suggest that sliding friction between the nose and/or flank of the tool and the newly machined surface is the primary source of acoustic emission. Changes in acoustic emission with tool wear were strongly material dependent.

  5. Origin of acoustic emission produced during single point machining

    SciTech Connect

    Heiple, C.R,.; Carpenter, S.H.; Armentrout, D.L.

    1991-01-01

    Acoustic emission was monitored during single point, continuous machining of 4340 steel and Ti-6Al-4V as a function of heat treatment. Acoustic emission produced during tensile and compressive deformation of these alloys has been previously characterized as a function of heat treatment. Heat treatments which increase the strength of 4340 steel increase the amount of acoustic emission produced during deformation, while heat treatments which increase the strength of Ti-6Al-4V decrease the amount of acoustic emission produced during deformation. If chip deformation were the primary source of acoustic emission during single point machining, then opposite trends in the level of acoustic emission produced during machining as a function of material strength would be expected for these two alloys. Trends in rms acoustic emission level with increasing strength were similar for both alloys, demonstrating that chip deformation is not a major source of acoustic emission in single point machining. Acoustic emission has also been monitored as a function of machining parameters on 6061-T6 aluminum, 304 stainless steel, 17-4PH stainless steel, lead, and teflon. The data suggest that sliding friction between the nose and/or flank of the tool and the newly machined surface is the primary source of acoustic emission. Changes in acoustic emission with tool wear were strongly material dependent. 21 refs., 19 figs., 4 tabs.

  6. Phylogeography of Toxoplasma gondii points to a South American origin.

    PubMed

    Bertranpetit, Emilie; Jombart, Thibaut; Paradis, Emmanuel; Pena, Hilda; Dubey, Jitender; Su, Chunlei; Mercier, Aurélien; Devillard, Sébastien; Ajzenberg, Daniel

    2017-03-01

    Toxoplasma gondii, a protozoan found ubiquitously in mammals and birds, is the etiologic agent of toxoplasmosis, a disease causing substantial public health burden worldwide, including about 200,000 new cases of congenital toxoplasmosis each year. Clinical severity has been shown to vary across geographical regions, with South America exhibiting the highest burden. Unfortunately, the drivers of these heterogeneities are still poorly understood, and the geographical origin and historical spread of the pathogen worldwide are currently uncertain. A worldwide sample of 168 T. gondii isolates gathered in 13 populations was sequenced for five fragments of genes (140 single nucleotide polymorphisms from 3153bp per isolate). Phylogeny based on Maximum likelihood methods with estimation of the time to the most recent common ancestor (TMRCA) and geostatistical analyses were performed for inferring the putative origin of T. gondii. We show that extant strains of the pathogen likely evolved from a South American ancestor, around 1.5 million years ago, and reconstruct the subsequent spread of the pathogen worldwide. This emergence is much more recent than the appearance of ancestral T. gondii, believed to have taken place about 11 My ago, and follows the arrival of felids in this part of the world. We posit that an ancestral lineage of T. gondii likely arrived in South America with felids and that the evolution of oral infectivity through carnivorism and the radiation of felids in this region enabled a new strain to outcompete the ancestral lineage and undergo a pandemic radiation.

  7. The Family Constellation Scale.

    ERIC Educational Resources Information Center

    Lemire, David

    The Family Constellation Scale (FC Scale) is an instrument that assesses perceived birth order in families. It can be used in counseling to help initiate conversations about various traits and assumptions that tend to characterize first-born, middle-born children, youngest-born, and only children. It provides both counselors and clients insights…

  8. On satellite constellation selection

    SciTech Connect

    Canavan, G.H.

    1991-05-01

    Analytical estimates can be used to produce and discuss optimal constellations. They are in close agreement with phase-space estimates and exact solutions. They suggest that distributions of inclined orbits could reduce satellite numbers by factors of 2--3 while improving uniformity. 4 refs., 2 figs.

  9. Constellation Program Update

    NASA Image and Video Library

    2006-06-04

    Scott J. Horowitz, NASA Associate Administrator for Exploration Systems, announces to NASA employees and members of the media the responsibilities of the NASA centers associated with the Constellation Program for robotic and human Moon and Mars exploration on Wednesday, June 5, 2006, at NASA Headquarters in Washington. Photo Credit: (NASA/Bill Ingalls)

  10. Constellation Program Update

    NASA Image and Video Library

    2006-06-04

    NASA Administrator Michael Griffin, left, and Scott J. Horowitz, NASA Associate Administrator for Exploration Systems, announce to NASA employees and members of the media the responsibilities of the NASA centers associated with the Constellation Program for robotic and human Moon and Mars exploration on Wednesday, June 5, 2006, at NASA Headquarters in Washington. Photo Credit: (NASA/Bill Ingalls)

  11. Constellation Program Update

    NASA Image and Video Library

    2006-06-04

    Dean Acosta, NASA Deputy Assistant Administrator and Press Secretary, left, moderates a NASA Update with NASA Administrator Michael Griffin, second from left, Scott J. Horowitz, NASA Associate Administrator for Exploration Systems and Jeff Hanley, Constellation Program Manager, right, on Wednesday, June 5, 2006, at NASA Headquarters in Washington. Photo Credit: (NASA/Bill Ingalls)

  12. Constellation Program Press Conference

    NASA Image and Video Library

    2006-06-04

    NASA Administrator Michael Griffin, left, looks on as Scott Horowitz, NASA Associate Administrator for Exploration Systems speaks during a press conference outlining specific center responsibilities associated with the Constellation Program for robotic and human Moon and Mars exploration, Monday, June 5, 2006, at NASA Headquarters in Washington. Photo Credit (NASA/Bill Ingalls)

  13. Constellation Program Update

    NASA Image and Video Library

    2006-06-04

    Dean Acosta, NASA Deputy Assistant Administrator and Press Secretary, left, moderates a NASA Update with NASA Administrator Michael Griffin, Scott J. Horowitz, NASA Associate Administrator for Exploration Systems and Jeff Hanley, Constellation Program Manager, right, on Wednesday, June 5, 2006, at NASA Headquarters in Washington. Photo Credit: (NASA/Bill Ingalls)

  14. Constellation Program Press Conference

    NASA Image and Video Library

    2006-06-04

    NASA Administrator Michael Griffin, speaks during a press conference outlining specific center responsibilities associated with the Constellation Program for robotic and human Moon and Mars exploration, Monday, June 5, 2006, at NASA Headquarters in Washington. Photo Credit (NASA/Bill Ingalls)

  15. Constellation Program Update

    NASA Image and Video Library

    2006-06-04

    NASA Administrator Michael Griffin addresses NASA employees and members of the media about the responsibilities of the NASA centers associated with the Constellation Program for robotic and human Moon and Mars exploration during a NASA Update on Wednesday, June 5, 2006, at NASA Headquarters in Washington. Photo Credit: (NASA/Bill Ingalls)

  16. Immunohistochemical analyses point to epidermal origin of human Merkel cells.

    PubMed

    Tilling, Thomas; Wladykowski, Ewa; Failla, Antonio Virgilio; Houdek, Pia; Brandner, Johanna M; Moll, Ingrid

    2014-04-01

    Merkel cells, the neurosecretory cells of skin, are essential for light-touch responses and may probably fulfill additional functions. Whether these cells derive from an epidermal or a neural lineage has been a matter of dispute for a long time. In mice, recent studies have clearly demonstrated an epidermal origin of Merkel cells. Given the differences in Merkel cell distribution between human and murine skin, it is, however, unclear whether the same holds true for human Merkel cells. We therefore attempted to gain insight into the human Merkel cell lineage by co-immunodetection of the Merkel cell marker protein cytokeratin 20 (CK20) with various proteins known to be expressed either in epidermal or in neural stem cells of the skin. Neither Sox10 nor Pax3, both established markers of the neural crest lineage, exhibited any cell co-labeling with CK20. By contrast, β1 integrin, known to be enriched in epidermal stem cells, was found in nearly 70 % of interfollicular epidermal and 25 % of follicular Merkel cells. Moreover, LRIG1, also enriched in epidermal stem cells, displayed significant co-immunolabeling with CK20 as well (approximately 20 % in the interfollicular epidermis and 7 % in the hair follicle, respectively). Further epidermal markers were detected in sporadic Merkel cells. Cells co-expressing CK20 with epidermal markers may represent a transitory state between stem cells and differentiated cells. β1 integrin is probably also synthesized by a large subset of mature Merkel cells. Summarizing, our data suggest that human Merkel cells may originate from epidermal rather than neural progenitors.

  17. Gravitational collapse of colloidal gels: Origins of the tipping point

    NASA Astrophysics Data System (ADS)

    Padmanabhan, Poornima; Zia, Roseanna

    2016-11-01

    Reversible colloidal gels are soft viscoelastic solids in which durable but reversible bonds permit on-demand transition from solidlike to liquidlike behavior; these O(kT) bonds also lead to ongoing coarsening and age stiffening, making their rheology inherently time dependent. To wit, such gels may remain stable for an extended time, but then suddenly collapse, sedimenting to the bottom of the container (or creaming to the top) and eliminating any intended functionality of the material. Although this phenomenon has been studied extensively in the experimental literature, the microscopic mechanism underlying the collapse is not well understood. Effects of gel age, interparticle attraction strength, and wall effects all have been shown to affect collapse behavior, but the microstructural transformations underlying the 'tipping point' remain murky. To study this behavior, we conduct large-scale dynamic simulation to model the structural and rheological evolution of colloidal gels subjected to various gravitational stresses, examining the detailed micromechanics in three temporal regimes: slow sedimentation prior to collapse; the tipping point leading to the onset of rapid collapse; and the subsequent compaction of the material as it approaches its final bed height. Acknowledgment for funding and support from the Office of Naval Research; the National Science Foundation; and NSF XSEDE.

  18. Armenian Names of Sky Constellations

    NASA Astrophysics Data System (ADS)

    Mickaelian, A. M.; Farmanyan, S. V.; Mikayelyan, A. A.

    2016-12-01

    The work is devoted to the correction and recovery of the Armenian names of the sky constellations, as they were forgotten or distorted during the Soviet years, mainly due to the translation from Russian. A total of 34 constellation names have been corrected. A brief overview of the history of the division of the sky into constellations and their naming is also given. At the end, the list of all 88 constellations is given with the names in Latin, English, Russian and Armenian.

  19. Anthropometric Requirements for Constellation

    NASA Technical Reports Server (NTRS)

    Raulu, Sudhakar; Margerum, Sarah; Dory, Jonathan; Rochlis, Jennifer

    2009-01-01

    This slide presentation reviews the requirement from an Anthropometric standpoint for the development of the Constellation's programs hardware, specifically the Orion crew exploration vehicle. The NASA JSC Anthropometry and Biomechanics Facility (ABF) provides anthropometry, strength, mobility, and mass properties requirements; gathers, interprets, manages and maintains the flight crew anthropometry database; and participates and provides input during crew selection. This is used to assist in requirements for vehicle and space suit design and for crew selection.

  20. Constellation Commodities Studies Summary

    NASA Technical Reports Server (NTRS)

    Dirschka, Eric

    2011-01-01

    Constellation program was NASA's long-term program for space exploration. The goal of the commodities studies was to solicit industry expertise in production, storage, and transportation required for future use and to improve efficiency and life cycle cost over legacy methods. Objectives were to consolidate KSC, CCAFS and other requirements; extract available industry expertise; identify commercial opportunities; and establish synergy with State of Florida partnerships. Study results are reviewed.

  1. A-1 to Constellation

    NASA Technical Reports Server (NTRS)

    2006-01-01

    The A-1 Test Stand at NASA Stennis Space Center near Bay St. Louis, Miss., was the focus of a ceremony held Thursday to transition the storied facility to a new program of work: testing the J-2X engines that will power the agency's next generation spacecraft, Ares I & V. Standing before the historic structure, with a plaque commemorating the change, are (from left) SSC Center Director Richard Gilbrech; NASA Associate Administrator for Exploration Systems Scott Horowitz; and NASA Space Operations Deputy Associate Administrator for Program Integration Michael Hawes. Ares vehicles are the crew and cargo launch vehicles being developed under NASA's Constellation Program.

  2. Constellation Training Facility Support

    NASA Technical Reports Server (NTRS)

    Flores, Jose M.

    2008-01-01

    The National Aeronautics and Space Administration is developing the next set of vehicles that will take men back to the moon under the Constellation Program. The Constellation Training Facility (CxTF) is a project in development that will be used to train astronauts, instructors, and flight controllers on the operation of Constellation Program vehicles. It will also be used for procedure verification and validation of flight software and console tools. The CxTF will have simulations for the Crew Exploration Vehicle (CEV), Crew Module (CM), CEV Service Module (SM), Launch Abort System (LAS), Spacecraft Adapter (SA), Crew Launch Vehicle (CLV), Pressurized Cargo Variant CM, Pressurized Cargo Variant SM, Cargo Launch Vehicle, Earth Departure Stage (EDS), and the Lunar Surface Access Module (LSAM). The Facility will consist of part-task and full-task trainers, each with a specific set of mission training capabilities. Part task trainers will be used for focused training on a single vehicle system or set of related systems. Full task trainers will be used for training on complete vehicles and all of its subsystems. Support was provided in both software development and project planning areas of the CxTF project. Simulation software was developed for the hydraulic system of the Thrust Vector Control (TVC) of the ARES I launch vehicle. The TVC system is in charge of the actuation of the nozzle gimbals for navigation control of the upper stage of the ARES I rocket. Also, software was developed using C standards to send and receive data to and from hand controllers to be used in CxTF cockpit simulations. The hand controllers provided movement in all six rotational and translational axes. Under Project Planning & Control, support was provided to the development and maintenance of integrated schedules for both the Constellation Training Facility and Missions Operations Facilities Division. These schedules maintain communication between projects in different levels. The Cx

  3. A-1 to Constellation

    NASA Image and Video Library

    2006-11-09

    The A-1 Test Stand at NASA Stennis Space Center near Bay St. Louis, Miss., was the focus of a ceremony held Thursday to transition the storied facility to a new program of work: testing the J-2X engines that will power the agency's next generation spacecraft, Ares I & V. Standing before the historic structure, with a plaque commemorating the change, are (from left) SSC Center Director Richard Gilbrech; NASA Associate Administrator for Exploration Systems Scott Horowitz; and NASA Space Operations Deputy Associate Administrator for Program Integration Michael Hawes. Ares vehicles are the crew and cargo launch vehicles being developed under NASA's Constellation Program.

  4. Neutron activation analysis traces copper artifacts to geographical point of origin

    NASA Technical Reports Server (NTRS)

    Conway, M.; Fields, P.; Friedman, A.; Kastner, M.; Metta, D.; Milsted, J.; Olsen, E.

    1967-01-01

    Impurities remaining in the metallic copper are identified and quantified by spectrographic and neutron activation analysis. Determination of the type of ore used for the copper artifact places the geographic point of origin of the artifact.

  5. Methods and Apparatuses for Signaling with Geometric Constellations in a Raleigh Fading Channel

    NASA Technical Reports Server (NTRS)

    Barsoum, Maged F. (Inventor); Jones, Christopher R. (Inventor)

    2015-01-01

    Communication systems are described that use signal constellations, which have unequally spaced (i.e., `geometrically` shaped) points. In many embodiments, the communication systems use specific geometric constellations that are capacity optimized at a specific SNR (signal to noise ratio). In addition, ranges within which the constellation points of a capacity optimized constellation can be perturbed and are still likely to achieve a given percentage of the optimal capacity increase compared to a constellation that maximizes d (sub min) (i.e. minimum distance between constellations) are also described. Capacity measures that are used in the selection of the location of constellation points include, but are not limited to, parallel decode (PD) capacity and joint capacity.

  6. Methodology and Method and Apparatus for Signaling with Capacity Optimized Constellations

    NASA Technical Reports Server (NTRS)

    Barsoum, Maged F. (Inventor); Jones, Christopher R. (Inventor)

    2016-01-01

    Design Methodology and Method and Apparatus for Signaling with Capacity Optimized Constellation Abstract Communication systems are described that use geometrically PSK shaped constellations that have increased capacity compared to conventional PSK constellations operating within a similar SNR band. The geometrically shaped PSK constellation is optimized based upon parallel decoding capacity. In many embodiments, a capacity optimized geometrically shaped constellation can be used to replace a conventional constellation as part of a firmware upgrade to transmitters and receivers within a communication system. In a number of embodiments, the geometrically shaped constellation is optimized for an Additive White Gaussian Noise channel or a fading channel. In numerous embodiments, the communication uses adaptive rate encoding and the location of points within the geometrically shaped constellation changes as the code rate changes.

  7. The autonomous sciencecraft constellations

    NASA Technical Reports Server (NTRS)

    Sherwood, R. L.; Chien, S.; Castano, R.; Rabideau, G.

    2003-01-01

    The Autonomous Sciencecraft Experiment (ASE) will fly onboard the Air Force TechSat 21 constellation of three spacecraft scheduled for launch in 2006. ASE uses onboard continuous planning, robust task and goal-based execution, model-based mode identification and reconfiguration, and onboard machine learning and pattern recognition to radically increase science return by enabling intelligent downlink selection and autonomous retargeting. In this paper we discuss how these AI technologies are synergistically integrated in a hybrid multi-layer control architecture to enable a virtual spacecraft science agent. Demonstration of these capabilities in a flight environment will open up tremendous new opportunities in planetary science, space physics, and earth science that would be unreachable without this technology.

  8. The autonomous sciencecraft constellations

    NASA Technical Reports Server (NTRS)

    Sherwood, R. L.; Chien, S.; Castano, R.; Rabideau, G.

    2003-01-01

    The Autonomous Sciencecraft Experiment (ASE) will fly onboard the Air Force TechSat 21 constellation of three spacecraft scheduled for launch in 2006. ASE uses onboard continuous planning, robust task and goal-based execution, model-based mode identification and reconfiguration, and onboard machine learning and pattern recognition to radically increase science return by enabling intelligent downlink selection and autonomous retargeting. In this paper we discuss how these AI technologies are synergistically integrated in a hybrid multi-layer control architecture to enable a virtual spacecraft science agent. Demonstration of these capabilities in a flight environment will open up tremendous new opportunities in planetary science, space physics, and earth science that would be unreachable without this technology.

  9. Crystal beginnings: constellations of holography

    NASA Astrophysics Data System (ADS)

    Richardson, Martin; Brown, Stephen

    2005-04-01

    In January 2004 at the SPIE Photonics West conference held in San Jose, an exhibition of the late Steve Benton"s work was held in a corridor leading of the conferencing rooms. The exhibition contained most, if not all of his finest works including one of his most spectacular, 'Crystal Beginnings'. It was during an interval in the programme that I found myself standing in front of this hologram, discussing its practical makings with fellow holographer Fred Unterseher. Since no notes were available regarding its design or indeed the holographic camera, Fred and I began to try and decipher how Benton had made it. During the discussion we seemed to attract a small crowd, and it soon became apparent that we were not alone in our fascination. One of those in the crowd turned out to be Oliver Cossairt, one of Benton"s ex-students at MIT. He contributed to our argument by informing us that he had asked Benton how the hologram was made. Benton"s answer was "all the clues are there!" The more I looked at the mass of reference points in space, the more it appeared as some form of 3D map or constellation! This paper explores that idea, and asks for reader"s participation in the completion of a questionnaire. Its answers will be used as reference points in a holographic map.

  10. SATCOM constellation power simulation

    SciTech Connect

    Capulli, J.; Badke, B.; Davis, G.

    1995-12-31

    Three basic variables directly impact the power and energy generated by the SATCOM satellite constellation and its individual Space Vehicles (SVs). They are (1) telecommunications traffic patterns, (2) network resource management controllables, and (3) system hardware and software performance. This power simulation has verified the robustness of the telecommunications architecture. It has validated the onboard resource allocation process from an SV and network level power and energy perspective. The analyses have led to development of operational procedures that prevent SV node outages, and maximize network telecommunication traffic capacity. The program objective is to optimize overall system operation, availability and quality of service. Achieving this goal requires a thorough understanding of the Electrical Power Subsystem and its interfaces. The EPS simulation model analyzes network level performance by evaluating requirement compliance in the expected operating environments. Specifically, the simulation tool evaluates different design approaches and network operational strategies from a power and energy perspective. As a result, optimal load management solutions will be implemented both on-board the SV and via ground station directed resource allocation strategies.

  11. Simulating 3D Spacecraft Constellations for Low Frequency Radio Imaging

    NASA Astrophysics Data System (ADS)

    Hegedus, A. M.; Amiri, N.; Lazio, J.; Belov, K.; Kasper, J. C.

    2016-12-01

    Constellations of small spacecraft could be used to realize a low-frequency phased array for either heliophysics or astrophysics observations. However, there are issues that arise with an orbiting array that do not occur on the ground, thus rendering much of the existing radio astronomy software inadequate for data analysis and simulation. In this work we address these issues and consider the performance of two constellation concepts. The first is a 32-spacecraft constellation for astrophysical observations, and the second is a 5-element concept for pointing to the location of radio emission from coronal mass ejections (CMEs). For the first, we fill the software gap by extending the APSYNSIM software to simulate the aperture synthesis for a radio interferometer in orbit. This involves using the dynamic baselines from the relative motion of the individual spacecraft as well as the capability to add galactic noise. The ability to simulate phase errors corresponding to positional uncertainty of the antennas was also added. The upgraded software was then used to model the imaging of a 32 spacecraft constellation that would orbit the moon to image radio galaxies like Cygnus A at .3-30 MHz. Animated images showing the improvement of the dirty image as the orbits progressed were made. RMSE plots that show how well the dirty image matches the input image as a function of integration time were made. For the second concept we performed radio interferometric simulations of the Sun Radio Interferometer Space Experiment (SunRISE) using the Common Astronomy Software Applications (CASA) package. SunRISE is a five spacecraft phased array that would orbit Earth to localize the low frequency radio emission from CMEs. This involved simulating the array in CASA, creating truth images for the CMEs over the entire frequency band of SunRISE, and observing them with the simulated array to see how well it could localize the true position of the CME. The results of our analysis show that we

  12. Dynamic Constellation Tasking and Management

    DTIC Science & Technology

    2013-03-01

    constellation of satellites in Low Earth Orbit (LEO) be used by tactical warfighters to collect images of battle space targets for near real-time decision...Constellations James Wertz (2005) provides an overview of five types of responsive orbits (Cobra, Magic, Sun Synchronous , Fast Access, and Repeat Coverage... Orbits ) and their uses. The most important qualities that make a responsive orbit useful are: low cost, good coverage, tactical applications, and

  13. Our Pittsburgh Constellation

    NASA Astrophysics Data System (ADS)

    Turnshek, Diane

    2015-08-01

    Riding on the Pittsburgh mayor’s keen interest in astronomy and the ongoing change of 40,000 city lights from mercury and sodium vapor to shielded LEDs, we organized a series of city-wide celestial art projects to bring attention to the skies over Pittsburgh. Light pollution public talks were held at the University of Pittsburgh’s Allegheny Observatory and other colleges. Earth Hour celebrations kicked off an intensive year of astronomy outreach in the city. Lights went out on March 28, 2015 from 8:30 to 9:30 pm in over fifty buildings downtown and in Oakland (the “Eds and Meds” center, where many Pittsburgh universities and hospitals are located). Our art contest was announced at the De-Light Pittsburgh celebration at the Carnegie Science Center during Astronomy Weekend. “Our Pittsburgh Constellation” is an interactive Google map of all things astronomical in the city. Different colored stars mark locations of planetariums, star parties, classes, observatories, lecture series, museums, telescope manufacturers and participating art galleries. Contest entrants submitted artwork depicting their vision of the constellation figure that incorporates and connects all the “stars” in our custom city map. Throughout the year, over a dozen artists ran workshops on painting star clusters, galaxies, nebulae, comets, planets and aurorae with discussions of light pollution solutions and scientific explanations of what the patrons were painting, including demonstrations with emission tubes and diffraction grating glasses. We will display the celestial art created in this International Year of Light at an art gallery as part of the City’s Department of Innovation & Performance March 2016 Earth Hour gala. We are thankful for the Astronomical Footprint grant from the Heinz Endowments, which allowed us to bring the worlds of science and art together to enact social change.

  14. BRITE-Constellation: Nanosatellites for precision photometry of bright stars

    NASA Astrophysics Data System (ADS)

    Weiss, W. W.; Moffat, A. F. J.; Schwarzenberg-Czerny, A.; Koudelka, O. F.; Grant, C. C.; Zee, R. E.; Kuschnig, R.; Mochnacki, St.; Rucinski, S. M.; Matthews, J. M.; Orleański, P.; Pamyatnykh, A. A.; Pigulski, A.; Alves, J.; Guedel, M.; Handler, G.; Wade, G. A.; Scholtz, A. L.; Scholtz

    2014-02-01

    BRITE-Constellation (where BRITE stands for BRIght Target Explorer) is an international nanosatellite mission to monitor photometrically, in two colours, brightness and temperature variations of stars brighter than V ~ 4, with precision and time coverage not possible from the ground. The current mission design consists of three pairs of 7 kg nanosats (hence ``Constellation'') from Austria, Canada and Poland carrying optical telescopes (3 cm aperture) and CCDs. One instrument in each pair is equipped with a blue filter; the other, a red filter. The first two nanosats (funded by Austria) are UniBRITE, designed and built by UTIAS-SFL (University of Toronto Institute for Aerospace Studies-Space Flight Laboratory) and its twin, BRITE-Austria, built by the Technical University Graz (TUG) with support of UTIAS-SFL. They were launched on 25 February 2013 by the Indian Space Agency, under contract to the Canadian Space Agency. Each BRITE instrument has a wide field of view (~ 24 degrees), so up to 15 bright stars can be observed simultaneously in 32 × 32 sub-rasters. Photometry (with reduced precision but thorough time sampling) of additional fainter targets will be possible through on-board data processing. A critical technical element of the BRITE mission is the three-axis attitude control system to stabilize a nanosat with very low inertia. The pointing stability is better than 1.5 arcminutes rms, a significant advance by UTIAS-SFL over any previous nanosatellite. BRITE-Constellation will primarily measure p- and g-mode pulsations to probe the interiors and ages of stars through asteroseismology. The BRITE sample of many of the brightest stars in the night sky is dominated by the most intrinsically luminous stars: massive stars seen at all evolutionary stages, and evolved medium-mass stars at the very end of their nuclear burning phases (cool giants and AGB stars). The Hertzsprung-Russell diagram for stars brighter than mag V=4 from which the BRITE-Constellation sample

  15. 77 FR 11168 - In the Matter of Exelon Corporation; Constellation Energy Group, Inc.; Nine Mile Nuclear Station...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-24

    ... Exelon Corporation; Constellation Energy Group, Inc.; Nine Mile Nuclear Station, LLC; Nine Mile Point... Ventures), and Constellation Energy Nuclear Group, LLC (CENG), acting on behalf of itself, and the licensee..., Constellation Energy Group, Inc. (CEG), whereby CEG would be merged into Exelon and ownership of CEG's...

  16. Evaluation of a satellite constellation for active debris removal

    NASA Astrophysics Data System (ADS)

    Sahara, Hironori

    2014-12-01

    economic efficiency. Though the size of constellation of debris removal satellites would be small originally, such a constellation of satellites should be one of the initial constellations of removal satellites to ensure the safety of the future orbital environment.

  17. System Constellations as a Tool Supporting Organisational Learning and Change Processes

    ERIC Educational Resources Information Center

    Birkenkrahe, Marcus

    2008-01-01

    Originally developed in the context of family therapy, system constellations are introduced using an organisational learning and system theoretical framework. Constellations are systemic group interventions using a spatial representation of the system elements. They correspond to deutero-learning processes and use higher-order systemic thinking.…

  18. System Constellations as a Tool Supporting Organisational Learning and Change Processes

    ERIC Educational Resources Information Center

    Birkenkrahe, Marcus

    2008-01-01

    Originally developed in the context of family therapy, system constellations are introduced using an organisational learning and system theoretical framework. Constellations are systemic group interventions using a spatial representation of the system elements. They correspond to deutero-learning processes and use higher-order systemic thinking.…

  19. EOS Terra Terra Constellation Exit/Future Maneuver Plans Update

    NASA Technical Reports Server (NTRS)

    Mantziaras, Dimitrios

    2016-01-01

    This EOS Terra Constellation Exit/Future Maneuver Plans Update presentation will discuss brief history of Terra EOM work; lifetime fuel estimates; baseline vs. proposed plan origin; resultant exit orbit; baseline vs. proposed exit plan; long term orbit altitude; revised lifetime proposal and fallback options.

  20. Constellation Lessons Learned Executive Summary

    NASA Technical Reports Server (NTRS)

    Thomas, L. Dale; Neubek, Deb

    2011-01-01

    This slide presentation reviews the lessons learned from the Constellation Program (CxP) and identified several factors that contributed to the inability of the CxP to meet the cost and schedule commitments. The review includes a significant section on the context in which the CxP operated since new programs are likely to experience the same constraints.

  1. Methodology and Method and Apparatus for Signaling With Capacity Optimized Constellations

    NASA Technical Reports Server (NTRS)

    Barsoum, Maged F. (Inventor); Jones, Christopher R. (Inventor)

    2014-01-01

    Communication systems are described that use geometrically shaped constellations that have increased capacity compared to conventional constellations operating within a similar SNR band. In several embodiments, the geometrically shaped is optimized based upon a capacity measure such as parallel decoding capacity or joint capacity. In many embodiments, a capacity optimized geometrically shaped constellation can be used to replace a conventional constellation as part of a firmware upgrade to transmitters and receivers within a communication system. In a number of embodiments, the geometrically shaped constellation is optimized for an Additive White Gaussian Noise channel or a fading channel. In numerous embodiments, the communication uses adaptive rate encoding and the location of points within the geometrically shaped constellation changes as the code rate changes.

  2. The power of inexpensive satellite constellations

    NASA Astrophysics Data System (ADS)

    Dyrud, Lars P.; La Tour, Rose; Swartz, William H.; Nag, Sreeja; Lorentz, Steven R.; Hilker, Thomas; Wiscombe, Warren J.; Papadakis, Stergios J.

    2014-06-01

    Two thematic drivers are motivating the science community towards constellations of small satellites, the revelation that many next generation system science questions are uniquely addressed with sufficient numbers of simultaneous space based measurements, and the realization that space is historically expensive, and in an environment of constrained costs, we must innovate to ―do more with less‖. We present analysis that answers many of the key questions surrounding constellations of scientific satellites, including research that resulted from the GEOScan community based effort originally intended as hosted payloads on Iridium NEXT. We present analysis that answers the question how many satellites does global system science require? Perhaps serendipitously, the analyses show that many of the key science questions independently converge towards similar results, i.e. that approximately 60+ satellites are needed for transformative, as opposed to incremental capability in system science. The current challenge is how to effectively transition products from design to mass production for space based instruments and vehicles. Ideally, the lesson learned from past designs and builds of various space products should pave the way toward a better manufacturing plan that utilizes just a fraction of the prototype`s cost. Using the commercial products industry implementations of mass customization as an example, we will discuss about the benefits of standardization in design requirements for space instruments and vehicles. For example, the instruments (payloads) are designed to have standardized elements, components, or modules that interchangeably work together within a linkage system. We conclude with a discussion on implementation plans and the new paradigms for community and international cooperation enabled by small satellite constellations.

  3. The role of unconscious homosexuality in the paranoid constellation.

    PubMed

    Frosch, J

    1981-10-01

    The literature dealing with Freud's original concept of unconscious homosexuality in the paranoid constellation is reviewed. Many of the more recent contributions view unconscious homosexual features as secondary to others; as such, they are pseudophenomena. This communication suggests that unconscious homosexuality in the male is denied, rejected, and projected because the passive, anal, sadomasochistic aspects are felt as degrading and humiliating. In the female, unconscious homosexuality is also felt as degrading and humiliating. In both sexes, the feeling of humiliation derives from real experiences in childhood. Unconscious homosexuality is viewed as the organizing principle in the paranoid constellation.

  4. Light Water Reactor Sustainability Constellation Pilot Project FY11 Summary Report

    SciTech Connect

    R. Johansen

    2011-09-01

    Summary report for Fiscal Year 2011 activities associated with the Constellation Pilot Project. The project is a joint effor between Constellation Nuclear Energy Group (CENG), EPRI, and the DOE Light Water Reactor Sustainability Program. The project utilizes two CENG reactor stations: R.E. Ginna and Nine Point Unit 1. Included in the report are activities associate with reactor internals and concrete containments.

  5. Prehistory of Zodiac Dating: Three Strata of Upper Paleolithic Constellations

    NASA Astrophysics Data System (ADS)

    Gurshtein, Alex A.

    A pattern of archaic proto-constellations is extracted from Aratus' "The Phaenomena" didactic poem list according to a size criterion elaborated earlier, and their symbolism is analyzed. As a result of this approach three celestial symbolical strata are discovered to be probably a reflection of the symbols for the Lower, the Middle and the Upper Worlds; the Under-World creatures have a water character, the Middle World ones are mostly anthropomorphic and flying beings are for the Upper World. The strata excerpted from Aratus' sky seems to be in agreement with the well-known Babylonian division into three god pathways for Ea (Enki), Anu and Enlil. There is a possibility of dating the pattern discovered because of precession's strong influence as far back as 16 thousand years, the result being supported by the comparison of different star group mean sizes. The archaic constellation pattern under consideration is a reasonable background of symbolical meanings for the first Zodiacal generation quartet (7.5 thousand years old) examined by the author previously. The enormous size of the Argo constellation (Ship of Argo and his Argonauts) as well as the large sizes of other southern constellations are explained as due to the existence of an accumulation zone near the South celestial pole. Some extra correlations between the reconstruction proposed and cultural data available are discussed. The paper is the second part of the investigation "On the Origin of the Zodiacal constellations" published in Vistas in Astronomy, vol.36, pp.171-190, 1993.

  6. Calculating point of origin of blood spatter using laser scanning technology.

    PubMed

    Hakim, Nashad; Liscio, Eugene

    2015-03-01

    The point of origin of an impact pattern is important in establishing the chain of events in a bloodletting incident. In this study, the accuracy and reproducibility of the point of origin estimation using the FARO Scene software with the FARO Focus(3D) laser scanner was determined. Five impact patterns were created for each of three combinations of distances from the floor (z) and the front wall (x). Fifteen spatters were created using a custom impact rig, scanned using the laser scanner, photographed using a DSLR camera, and processed using the Scene software. Overall results gave a SD = 3.49 cm (p < 0.0001) in the x-direction, SD = 1.14 cm (p = 0.9291) in the y-direction, and SD = 9.08 cm (p < 0.0115) in the z-direction. The technique performs within literature ranges of accepted accuracy and reproducibility and is comparable to results reported for other virtual stringing software.

  7. Influence of Ethnicity, Gender and Answering Mode on a Virtual Point-to-Origin Task

    PubMed Central

    Kitson, Alexandra; Sproll, Daniel; Riecke, Bernhard E.

    2016-01-01

    In a virtual point-to-origin task, participants seem to show different response patterns and underlying strategies for orientation, such as “turner” and “non-turner” response patterns. Turners respond as if succeeding to update simulated heading changes, and non-turners respond as if failing to update their heading, resulting in left-right hemisphere errors. We present two other response patterns, “non-movers” and “spinners,” that also appear to result in failures to update heading. We have three specific goals in mind: (1) extend previous findings of higher turner rates with spatial language response mode using a point-to-origin task instead of a triangle completion task; (2) replicate the gender effect of males more likely responding as turners; (3) examine ethnicity influence. Designed as a classroom study, we presented participants (N = 498) with four passages through a virtual star field. Participants selected the direction pointing to the origin from four multiple-choice items. Response mode was either pictograms or written language, chosen to compare with similar studies and see if these response modes have an effect on virtual orientation behavior. Results show a majority of participants (48.35%) classified as non-turners, 32.93% turners, 15.57% as non-movers, and 3.14% as spinners. A multinomial regression model reached 49% classification performance. Written spatial language, compared to pictograms, made turner response patterns more likely; this effect was more pronounced for Chinese participants and among females, but not male Caucasians. Moreover, higher turner numbers for written spatial language extends Avraamides findings of higher turner numbers when participants turned their bodies toward the origin but not when they responded verbally. Using pictorial response mode (i.e., top-down picture of a head) may have increased cognitive load because it could be considered more embodied. It remains to be seen how we can reduce the reference

  8. Microscopic origin of the '0.7-anomaly' in quantum point contacts.

    PubMed

    Bauer, Florian; Heyder, Jan; Schubert, Enrico; Borowsky, David; Taubert, Daniela; Bruognolo, Benedikt; Schuh, Dieter; Wegscheider, Werner; von Delft, Jan; Ludwig, Stefan

    2013-09-05

    Quantum point contacts are narrow, one-dimensional constrictions usually patterned in a two-dimensional electron system, for example by applying voltages to local gates. The linear conductance of a point contact, when measured as function of its channel width, is quantized in units of GQ = 2e(2)/h, where e is the electron charge and h is Planck's constant. However, the conductance also has an unexpected shoulder at ∼0.7GQ, known as the '0.7-anomaly', whose origin is still subject to debate. Proposed theoretical explanations have invoked spontaneous spin polarization, ferromagnetic spin coupling, the formation of a quasi-bound state leading to the Kondo effect, Wigner crystallization and various treatments of inelastic scattering. However, explicit calculations that fully reproduce the various experimental observations in the regime of the 0.7-anomaly, including the zero-bias peak that typically accompanies it, are still lacking. Here we offer a detailed microscopic explanation for both the 0.7-anomaly and the zero-bias peak: their common origin is a smeared van Hove singularity in the local density of states at the bottom of the lowest one-dimensional subband of the point contact, which causes an anomalous enhancement in the Hartree potential barrier, the magnetic spin susceptibility and the inelastic scattering rate. We find good qualitative agreement between theoretical calculations and experimental results on the dependence of the conductance on gate voltage, magnetic field, temperature, source-drain voltage (including the zero-bias peak) and interaction strength. We also clarify how the low-energy scale governing the 0.7-anomaly depends on gate voltage and interactions. For low energies, we predict and observe Fermi-liquid behaviour similar to that associated with the Kondo effect in quantum dots. At high energies, however, the similarities between the 0.7-anomaly and the Kondo effect end.

  9. NASA Project Constellation Systems Engineering Approach

    NASA Technical Reports Server (NTRS)

    Dumbacher, Daniel L.

    2005-01-01

    NASA's Office of Exploration Systems (OExS) is organized to empower the Vision for Space Exploration with transportation systems that result in achievable, affordable, and sustainable human and robotic journeys to the Moon, Mars, and beyond. In the process of delivering these capabilities, the systems engineering function is key to implementing policies, managing mission requirements, and ensuring technical integration and verification of hardware and support systems in a timely, cost-effective manner. The OExS Development Programs Division includes three main areas: (1) human and robotic technology, (2) Project Prometheus for nuclear propulsion development, and (3) Constellation Systems for space transportation systems development, including a Crew Exploration Vehicle (CEV). Constellation Systems include Earth-to-orbit, in-space, and surface transportation systems; maintenance and science instrumentation; and robotic investigators and assistants. In parallel with development of the CEV, robotic explorers will serve as trailblazers to reduce the risk and costs of future human operations on the Moon, as well as missions to other destinations, including Mars. Additional information is included in the original extended abstract.

  10. Zero point energy as origin of dark energy and dark matter

    NASA Astrophysics Data System (ADS)

    Lehnert, Bo

    2012-04-01

    An attempt is made to explain dark energy and dark matter of the expanding universe in terms of the zero point vacuum energy. This analysis is mainly limited to later stages of an observable nearly flat universe. It is based on a revised formulation of the spectral distribution of the zero point energy, for an ensemble in a defined statistical equilibrium having finite total energy density. The steady and dynamic states are studied for a spherical cloud of zero point energy photons. The "antigravitational" force due to its pressure gradient then represents dark energy, and its gravitational force due to the energy density represents dark matter. Four fundamental results come out of the theory. First, the lack of emitted radiation becomes reconcilable with the concepts of dark energy and dark matter. Second, the crucial coincidence problem of equal orders of magnitude of mass density and vacuum energy density cannot be explained by the cosmological constant, but is resolved by the present variable concepts which originate from the same photon gas balance. Third, the present approach becomes reconcilable with cosmical dimensions and with the radius of the observable universe. Fourth, the deduced acceleration of the expansion agrees with the observed one.

  11. Laser satellite constellations for strategic defense - an analytic model

    SciTech Connect

    Parmentola, J.A.; Milton, A.F.

    1987-10-01

    Using mainly geometric reasoning, an analytic model is constructed that predicts the required characteristics of an orbiting constellation of laser battle stations, each of which is designed to destroy ballistic missiles during their boost phase. The geometry of the constellation configuration and some general aspects of the coverage problem are discussed. The determination of the absentee ratio falls into two main categories that depend upon whether the Soviet ICBM threat is concentrated at a single location or whether it is distributed as it is now. A point-threat model and a distributive threat model are considered, the determination of the respective kill rates for these models is discussed, and the scaling properties of the laser constellation with respect to a change in the quantitative nature of the two types of ICBM threats are considered.

  12. Flying the Earth Observing Constellations

    NASA Technical Reports Server (NTRS)

    Kelly, Angelita C.; Case, Warren F.

    2004-01-01

    Prior to the launch of the Earth Observing System (EOS) Terra and Landsat-7 satellites in 1999, the Project Scientists for the two missions and the Earth Science Data and Information System (ESDIS) Project at the Goddard Space Flight Center signed an inter-project agreement document describing their plan to fly in loose formation, approximately 20 minutes within each other. In November 2000, a technology demonstration satellite, Earth Observer-1 (EO-1), was launched into the same orbit as that of Landsat-7 and Terra, with a goal of flying within a minute from Landsat-7. The SAC-C satellite, developed and operated by the government of Argentina, was launched along with EO-1, with a goal of flying near both Terra and Landsat-7. This formation enables the scientists to make use of the scientific synergy among the instruments on the different spacecraft. This group of satellites constitutes the morning constellation, which is led by the Landsat-7, which has a mean local time (MLT) at 10:00 a.m. In May 2002, the EOS Aqua satellite was launched into an orbit with an altitude of 705 km. and a 1:30 p.m. MLT. Two smaller satellites, CALIPSO (a joint U.S./French mission), and CloudSat (a joint NASA/Colorado State University/Air Force mission), plan to fly in tight formation, within 15 seconds of each other. In addition, CALIPSO and CloudSat also plan to be within 30 to 60 seconds of the Aqua satellite. A third satellite, PARASOL, managed by the French Space Agency, CNES, will be placed within a minute of the CALIPSO satellite. In 2004, the Aura satellite will be launched and phased in relation to the Aqua satellite, such that the instruments on Aura will be able to view the same mass of air no later than 8 minutes after the instruments on Aqua have observed it. Representatives from each mission are currently documenting a plan on how they will coordinate on-orbit operations. Why are all these satellites planning to fly as a constellation? The answer is that as a

  13. The Constellation-X Observatory

    NASA Technical Reports Server (NTRS)

    Weaver, Kimberly

    2003-01-01

    The Constellation X-ray mission will revolutionize X-ray spectroscopy and will provide a key component of NASA's '!Beyond Einstein" program. Over the past 35 years, X-ray astronomy has grown from infancy to near-maturity and is now an indispensable astrophysical tool. Constellation-X will transform this field from the exploratory spectroscopic era of Chandra and XMM to an era of fully comprehensive spectroscopic studies. The mission will consist of four 1.6-meter X-ray telescopes orbiting the Earth/Sun system. By providing a factor of 100 increase in throughput over previous missions, as well as high spectral resolution and a broad energy bandpass, Constellation-X will obtain high quality spectra for all classes of X-ray sources over a wide range of luminosity and redshift. It will study the warping of space and time near black holes, determine the distribution of ordinary matter, dark matter and dark energy, and probe detailed physical processes that occur at temperatures, densities and pressures far beyond those achievable in Earth-bound laboratories.

  14. Science with Constellation-X

    NASA Technical Reports Server (NTRS)

    Hornschemeier, Ann (Editor); Garcia, Michael (Editor)

    2005-01-01

    NASA's upcoming Constellation-X mission, one of two flagship missions in the Beyond Einstein program, will have more than 100 times the collecting area of any previous spectroscopic mission operating in the 0.25-40 keV bandpass and will enable high-throughput, high spectral resolution studies of sources ranging from the most luminous accreting supermassive black holes in the Universe to the disks around young stars where planets form. This booklet, which was assembled during early 2005 using the contributions of a large team of Astrophysicists, outlines the important scientific questions for the decade following this one and describes the areas where Constellation-X is going to have a major impact. These areas include the exploration of the space-time geometry of black holes spanning nine orders of magnitude in mass and the nature of the dark energy and dark matter which govern the expansion and ultimate fate of the Universe. Constellation-X will also explore processes referred to as "cosmic feedback" whereby mechanical energy, radiation, and chemical elements from star formation and black holes are returned to interstellar and intergalactic medium, profoundly affecting the development of structure in the Universe, and will also probe all the important life cycles of matter, from stellar and planetary birth to stellar death via supernova to stellar endpoints in the form of accreting binaries and supernova remnants.

  15. A design method for constellation of lifting reentry vehicles

    NASA Astrophysics Data System (ADS)

    Xiang, Yu; Kun, Liu

    2017-03-01

    As the reachable domain of a single lifting reentry vehicle is not large enough to cover the whole globe in a short time, which is disadvantageous to responsive operation, it is of great significance to study on how to construct a constellation of several lifting reentry vehicles to responsively reach any point of the globe. This paper addresses a design method for such a constellation. Firstly, an approach for calculating the reachable domain of a single lifting reentry vehicle is given, using the combination of Gauss Pseudospectral Method and SQP method. Based on that, the entire reachable domain taking the limit of responsive time into consideration is simplified reasonably to reduce the complexity of the problem. Secondly, a Streets-of-Coverage (SOC) method is used to design the constellation and the parameters of the constellation are optimized through simple analysis and comparison. Lastly, a point coverage simulation method is utilized to verify the correctness of the optimization result. The verified result shows that 6 lifting reentry vehicles whose maximum lift-to-drag ratio is 1.7 can reach nearly any point on the earth's surface between -50° and 50° in less than 90 minutes.

  16. Dependency of geodynamic parameters on the GNSS constellation

    NASA Astrophysics Data System (ADS)

    Scaramuzza, Stefano; Dach, Rolf; Beutler, Gerhard; Arnold, Daniel; Sušnik, Andreja; Jäggi, Adrian

    2017-07-01

    Significant differences in time series of geodynamic parameters determined with different Global Navigation Satellite Systems (GNSS) exist and are only partially explained. We study whether the different number of orbital planes within a particular GNSS contributes to the observed differences by analyzing time series of geocenter coordinates (GCCs) and pole coordinates estimated from several real and virtual GNSS constellations: GPS, GLONASS, a combined GPS/GLONASS constellation, and two virtual GPS sub-systems, which are obtained by splitting up the original GPS constellation into two groups of three orbital planes each. The computed constellation-specific GCCs and pole coordinates are analyzed for systematic differences, and their spectral behavior and formal errors are inspected. We show that the number of orbital planes barely influences the geocenter estimates. GLONASS' larger inclination and formal errors of the orbits seem to be the main reason for the initially observed differences. A smaller number of orbital planes may lead, however, to degradations in the estimates of the pole coordinates. A clear signal at three cycles per year is visible in the spectra of the differences between our estimates of the pole coordinates and the corresponding IERS 08 C04 values. Combinations of two 3-plane systems, even with similar ascending nodes, reduce this signal. The understanding of the relation between the satellite constellations and the resulting geodynamic parameters is important, because the GNSS currently under development, such as the European Galileo and the medium Earth orbit constellation of the Chinese BeiDou system, also consist of only three orbital planes.

  17. Constellation

    NASA Image and Video Library

    2008-02-15

    SHOWN IS A CONCEPT IMAGE OF THE ARES V EARTH DEPARTURE STAGE AND LUNAR SURFACE ACCESS MODULE DOCKED WITH THE ORION CREW EXPLORATION VEHICLE IN EARTH ORBIT. THE DEPARTURE STAGE, POWERED BY A J-2X ENGINE, IS NEEDED TO ESCAPE EARTH'S GRAVITY AND SEND THE CREW VEHICLE AND LUNAR MODULE ON THEIR JOURNEY TO THE MOON.

  18. Adaptation in Multi-Satellite Constellation Cooperation

    DTIC Science & Technology

    2014-08-01

    AFRL-RV-PS- AFRL-RV-PS- TR-2014-0113 TR-2014-0113 ADAPTATION IN MULTI-SATELLITE CONSTELLATION COOPERATION Chengyu Cao University of Connecticut...Multi-Satellite Constellation Cooperation 5a. CONTRACT NUMBER FA9453-13-1-0287 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S) 5d... constellations . 15. SUBJECT TERMS Autonomous space systems, High fidelity satellite simulator, multi-objective optimization 16. SECURITY CLASSIFICATION OF

  19. Global Positioning System Constellation Clock Performance

    DTIC Science & Technology

    2002-12-01

    of the Global Positioning System ( GPS ) constellation with respect to the lifetimes of space vehicles and space vehicle clocks, both active and...ABSTRACT An overview of the Global Positioning System ( GPS ) constellation with respect to the lifetimes of space vehicles and space vehicle clocks, both...34th Annual Precise Time and Time Interval (PTTI) Meeting 77 GLOBAL POSITIONING SYSTEM CONSTELLATION CLOCK PERFORMANCE Jay Oaks and Marie

  20. Vestigial phragmocone in the gladius points to a deepwater origin of squid (Mollusca: Cephalopoda)

    NASA Astrophysics Data System (ADS)

    Arkhipkin, Alexander I.; Bizikov, Vyacheslav A.; Fuchs, Dirk

    2012-03-01

    The microstructure of the gladius cone was investigated in six species of nektonic squid: shallow-water Loligo gahi (Loliginidae), pelagic eurybathic Illex argentinus, Todarodes pacificus, Dosidicus gigas (Ommastrephidae), and deepwater Onykia ingens (Onychoteuthidae) and Gonatus antarcticus (Gonatidae) using state-of-the-art microscopy. Apart from L. gahi, all other species had septa-like layers in the gladius cone, which for the first time were investigated in detail and compared with those in extinct Cretaceous belemnites Hibolithes sp. and Pachyteuthis sp., and spirulid Cyrtobelus sp. It was found that the organic layers of the gladius cone in recent squid can be homologized with the organic components of the shell in fossil phragmocone-bearing coleoids. The septa-like layers in modern gladius cones therefore represent a vestigial phragmocone composed of organic septal rudiments of the ancestral phragmocone that has lost the siphuncle and gas-filled chambers. The well-developed rostrum in onychoteuthids and small rostrum of the gladius in ommastrephids and gonatids can be seen as homologous with the belemnoid rostrum, which may indicate a close phylogenetic relationship between belemnites and at least some squid. Possible evolutionary pathways of the reduction of the functional phragmocone in squid ancestors are discussed. Several features such as the loss of shell calcification, deep water speciation, and the structure of the equilibrium organ point to a deep-water origin of squids.

  1. Best Practices for Operations of Satellite Constellations

    NASA Technical Reports Server (NTRS)

    Howard, Joseph; Oza, Dipak; Smith, Danford S.

    2006-01-01

    This paper presents the best practices used by several commercial and government operators of satellite constellations. These best practices were identified through a series of seminars and discussions held at NASA Goddard Space Flight Center (GSFC). The best practices are arrived through many years of experience and improvements made in the operations procedures and the operational systems with the primary drivers as mission safety and cost effectiveness. This paper discusses the operational aspects associated with how different organizations manage complexities of constellation operations. For the purposes of this paper, satellite constellations are groups of similar spacecraft with more than one spacecraft needed to fully accomplish the constellation's mission

  2. Constellation X-Ray Mission and Support

    NASA Technical Reports Server (NTRS)

    Tananbaum, H.; Grady, Jean (Technical Monitor)

    2002-01-01

    This is the Third Annual Report of work performed by the Smithsonian Astrophysical Observatory (SAO) for NASA Goddard Space Flight Center (GSFC) under Cooperative Agreement NCC5-3681. The Agreement is entitled 'Constellation X-ray Mission Study and Support.' Work performed through January 31, 2001 was reported in a supplement to the Second Annual Report. That supplemental report was submitted in order to obtain funding subsequent to March 2001 which has, as the result of prior funding actions, become the de facto beginning of the funding year under the Agreement. This report covers the balance of the third year of the Agreement from February 1, 2001 through September 30, 2001. The Agreement as currently configured runs for two more years. When funding is significantly different from the originally approved amounts, SAO submits a revised budget. One such revision was submitted last year and was the basis for funding a portion of the work reported here. This report summarizes the main areas of SAO activity. Most of the work has been performed jointly with personnel from GSFC and Marshall Space Flight Center (MSFC). Consequently, we do not claim that such activities were carried out exclusively by SAO. Rather, we describe SAO participation in these efforts. Under the Agreement, SAO performed work in seven major areas of activity. These areas related to: (1) Constellation X-ray Mission Facility Definition Team and Study Management; (2) Science Support; (3) Spectroscopy X-ray Telescope (SXT); (4) Systems Engineering; (5) Travel; and (6) In-house Management and Coordination.

  3. Multisatellite constellation configuration selection for multiregional highly elliptical orbit constellations

    NASA Technical Reports Server (NTRS)

    Matossian, Mark G.

    1994-01-01

    The Archimedes Project is a joint effort of the European Space Agency (ESA) and the National Space Development Agency of Japan (NASDA). The primary goal of the Archimedes project is to perform a technical feasibility analysis and preliminary design of a highly inclined multisatellite constellation for direct broadcast and mobile communications services for Europe, Japan and much of North America. This report addresses one aspect of this project, specifically an analysis of continuous satellite coverage using multiregional highly elliptical orbits (M-HEO's). The analysis methodology and ensuing software tool, named SPIFF, were developed specifically for this project by the author during the summer of 1992 under the STA/NSF Summer Institute in Japan Program at Tsukuba Space Center.

  4. Hidden topological constellations and polyvalent charges in chiral nematic droplets

    PubMed Central

    Posnjak, Gregor; Čopar, Simon; Muševič, Igor

    2017-01-01

    Topology has an increasingly important role in the physics of condensed matter, quantum systems, material science, photonics and biology, with spectacular realizations of topological concepts in liquid crystals. Here we report on long-lived hidden topological states in thermally quenched, chiral nematic droplets, formed from string-like, triangular and polyhedral constellations of monovalent and polyvalent singular point defects. These topological defects are regularly packed into a spherical liquid volume and stabilized by the elastic energy barrier due to the helical structure and confinement of the liquid crystal in the micro-sphere. We observe, for the first time, topological three-dimensional point defects of the quantized hedgehog charge q=−2, −3. These higher-charge defects act as ideal polyvalent artificial atoms, binding the defects into polyhedral constellations representing topological molecules. PMID:28220770

  5. Hidden topological constellations and polyvalent charges in chiral nematic droplets

    NASA Astrophysics Data System (ADS)

    Posnjak, Gregor; Čopar, Simon; Muševič, Igor

    2017-02-01

    Topology has an increasingly important role in the physics of condensed matter, quantum systems, material science, photonics and biology, with spectacular realizations of topological concepts in liquid crystals. Here we report on long-lived hidden topological states in thermally quenched, chiral nematic droplets, formed from string-like, triangular and polyhedral constellations of monovalent and polyvalent singular point defects. These topological defects are regularly packed into a spherical liquid volume and stabilized by the elastic energy barrier due to the helical structure and confinement of the liquid crystal in the micro-sphere. We observe, for the first time, topological three-dimensional point defects of the quantized hedgehog charge q=-2, -3. These higher-charge defects act as ideal polyvalent artificial atoms, binding the defects into polyhedral constellations representing topological molecules.

  6. Science-Enabling MicroSpacecraft Constellations for Mars

    NASA Astrophysics Data System (ADS)

    Mauritz, A.; Patel, B.

    2000-07-01

    By leveraging commercially-developed spacecraft constellation technology, a wide variety of Mars missions can be accomplished ranging from single microspacecraft missions costing less than 50 million to constellations of microspacecraft that provide distributed remote sensing capabilities. Remote sensing missions that require global coverage of Mars can be conducted by constellations of microspacecraft. These microspacecraft provide focused science at low risk. As an additional benefit, these microspacecraft could easily be modified to provide the communication and navigation infrastructure necessary for other complimentary surface science missions. Orbital Sciences Corporation has extensive experience developing and operating microspacecraft constellations. The figures illustrate microspacecraft designs applicable to a wide variety of Mars missions. Based on the highly proven Microstar bus, this spacecraft is capable of dedicated or shared launches on a number of launch vehicles including Pegasus, Taurus, Delta II, Delta III, and Ariane 5. Missions enabled by these microspacecraft include constellation-based scientific remote sensing, communications relay, navigation, and distributed aperture sensing. Additionally, this bus can support singular missions focused on probe delivery, remote sensing, or remote monitoring of, and data collection from land-based elements conducting Mars in situ science. The spacecraft bus utilizes a common set of low mass, low power avionics successfully demonstrated on 38 MicroStar spacecraft currently in operation. By optimizing mechanical designs around specific launch vehicles and payloads, this bus offers a robust means by which to realize many missions. Depending on launch vehicle capability, this bus can support payloads weighing up 70 kg with average payload power requirements in excess of 50W. These proven spacecraft platforms provide an affordable means by which to execute exciting science missions at low risk. A figure is

  7. ISHM Implementation for Constellation Systems

    NASA Technical Reports Server (NTRS)

    Figueroa, Fernando; Holland, Randy; Schmalzel, John; Duncavage, Dan; Crocker, Alan; Alena, Rick

    2006-01-01

    Integrated System Health Management (ISHM) is a capability that focuses on determining the condition (health) of every element in a complex System (detect anomalies, diagnose causes, prognosis of future anomalies), and provide data, information, and knowledge (DIaK) "not just data" to control systems for safe and effective operation. This capability is currently done by large teams of people, primarily from ground, but needs to be embedded on-board systems to a higher degree to enable NASA's new Exploration Mission (long term travel and stay in space), while increasing safety and decreasing life cycle costs of systems (vehicles; platforms; bases or outposts; and ground test, launch, and processing operations). This viewgraph presentation reviews the use of ISHM for the Constellation system.

  8. Autonomy Architectures for a Constellation of Spacecraft

    NASA Technical Reports Server (NTRS)

    Barrett, Anthony

    2000-01-01

    Until the past few years, missions typically involved fairly large expensive spacecraft. Such missions have primarily favored using older proven technologies over more recently developed ones, and humans controlled spacecraft by manually generating detailed command sequences with low-level tools and then transmitting the sequences for subsequent execution on a spacecraft controller. This approach toward controlling a spacecraft has worked spectacularly on previous missions, but it has limitations deriving from communications restrictions - scheduling time to communicate with a particular spacecraft involves competing with other projects due to the limited number of deep space network antennae. This implies that a spacecraft can spend a long time just waiting whenever a command sequence fails. This is one reason why the New Millennium program has an objective to migrate parts of mission control tasks onboard a spacecraft to reduce wait time by making spacecraft more robust. The migrated software is called a "remote agent" and has 4 components: a mission manager to generate the high level goals, a planner/scheduler to turn goals into activities while reasoning about future expected situations, an executive/diagnostics engine to initiate and maintain activities while interpreting sensed events by reasoning about past and present situations, and a conventional real-time subsystem to interface with the spacecraft to implement an activity's primitive actions. In addition to needing remote planning and execution for isolated spacecraft, a trend toward multiple-spacecraft missions points to the need for remote distributed planning and execution. The past few years have seen missions with growing numbers of probes. Pathfinder has its rover (Sojourner), Cassini has its lander (Huygens), and the New Millenium Deep Space 3 (DS3) proposal involves a constellation of 3 spacecraft for interferometric mapping. This trend is expected to continue to progressively larger fleets. For

  9. Constellations: A New Paradigm for Earth Observations

    NASA Technical Reports Server (NTRS)

    Kelly, Angelita C.; Volz, Stephen M.; Yuhas, Cheryl L.; Case, Warren F.

    2009-01-01

    The last decade has seen a significant increase in the number and the capabilities of remote sensing satellites launched by the international community. A relatively new approach has been the launching of satellites into heterogeneous constellations. Constellations provide the scientists a capability to acquire science data, not only from specific instruments on a single satellite, but also from instruments on other satellites that fly in the same orbit. Initial results from the A-Train (especially following the CALIPSO/CloudSat launch) attest to the tremendous scientific value of constellation flying. This paper provides a history of the constellations (particularly the A-Train) and how the A-Train mission design was driven by science requirements. The A-Train has presented operational challenges which had not previously been encountered. Operations planning had to address not only how the satellites of each constellation operate safely together, but also how the two constellations fly in the same orbits without interfering with each other when commands are uplinked or data are downlinked to their respective ground stations. This paper discusses the benefits of joining an on-orbit constellation. When compared to a single, large satellite, a constellation infrastructure offers more than just the opportunities for coincidental science observations. For example, constellations reduce risks by distributing observing instruments among numerous satellites; in contrast, a failed launch or a system failure in a single satellite would lead to loss of all observations. Constellations allow for more focused, less complex satellites. Constellations distribute the development, testing, and operations costs among various agencies and organizations for example, the Morning and Afternoon Constellations involve several agencies within the U.S. and in other countries. Lastly, this paper addresses the need to plan for the long-term evolution of a constellation. Agencies need to have

  10. Simulating the Liaison Navigation Concept in a Geo + Earth-Moon Halo Constellation

    NASA Technical Reports Server (NTRS)

    Fujimoto, K.; Leonard, J. M.; McGranaghan, R. M.; Parker, J. S.; Anderson, R. L.; Born, G. H.

    2012-01-01

    Linked Autonomous Interplanetary Satellite Orbit Navigation, or LiAISON, is a novel satellite navigation technique where relative radiometric measurements between two or more spacecraft in a constellation are processed to obtain the absolute state of all spacecraft. The method leverages the asymmetry of the gravity field that the constellation exists in. This paper takes a step forward in developing a high fidelity navigation simulation for the LiAISON concept in an Earth-Moon constellation. In particular, we aim to process two-way Doppler measurements between a satellite in GEO orbit and another in a halo orbit about the Earth-Moon L1 point.

  11. Simulating the Liaison Navigation Concept in a Geo + Earth-Moon Halo Constellation

    NASA Technical Reports Server (NTRS)

    Fujimoto, K.; Leonard, J. M.; McGranaghan, R. M.; Parker, J. S.; Anderson, R. L.; Born, G. H.

    2012-01-01

    Linked Autonomous Interplanetary Satellite Orbit Navigation, or LiAISON, is a novel satellite navigation technique where relative radiometric measurements between two or more spacecraft in a constellation are processed to obtain the absolute state of all spacecraft. The method leverages the asymmetry of the gravity field that the constellation exists in. This paper takes a step forward in developing a high fidelity navigation simulation for the LiAISON concept in an Earth-Moon constellation. In particular, we aim to process two-way Doppler measurements between a satellite in GEO orbit and another in a halo orbit about the Earth-Moon L1 point.

  12. Modelling the transport of solid contaminants originated from a point source

    NASA Astrophysics Data System (ADS)

    Salgueiro, Dora V.; Conde, Daniel A. S.; Franca, Mário J.; Schleiss, Anton J.; Ferreira, Rui M. L.

    2017-04-01

    results obtained with STAV-2D show the formation of a shock wave, radially propagating from the point discharge, and secondary shocks originated by reflections at the basin walls. Laboratory results evidenced the presence of two main disturbances: a wave front near the side wall and another one resulting from dispersive processes. The dispersive phenomenon suggests the presence of oscillations, instead of the constant energy state that is characteristic of isolated rarefaction waves. The ability of the existing model to reproduce these details of the experiment is assessed and discussed. The validated two-layer hydrodynamics model is seen as a proxy for fluvial flows with different sediment concentration regions and can be used for the prediction and monitoring of spatial and temporal distribution of sediments and the adsorbed phases of contaminants. Acknowledgements This research was partially funded by the Portuguese Foundation for Science and Technology (FCT) through project RECI/ECM-HID/0371/2012 and through a H2Doc - Environmental Hydraulics and Hydrology doctoral grant (PD/BD/113620/2015) and by the Laboratory of Hydraulic Constructions (LCH), École polytechnique fédérale de Lausanne.

  13. Autonomy Architectures for a Constellation of Spacecraft

    NASA Technical Reports Server (NTRS)

    Barrett, Anthony

    2000-01-01

    Until the past few years, missions typically involved fairly large expensive spacecraft. Such missions have primarily favored using older proven technologies over more recently developed ones, and humans controlled spacecraft by manually generating detailed command sequences with low-level tools and then transmitting the sequences for subsequent execution on a spacecraft controller. This approach toward controlling a spacecraft has worked spectacularly on previous missions, but it has limitations deriving from communications restrictions - scheduling time to communicate with a particular spacecraft involves competing with other projects due to the limited number of deep space network antennae. This implies that a spacecraft can spend a long time just waiting whenever a command sequence fails. This is one reason why the New Millennium program has an objective to migrate parts of mission control tasks onboard a spacecraft to reduce wait time by making spacecraft more robust. The migrated software is called a "remote agent" and has 4 components: a mission manager to generate the high level goals, a planner/scheduler to turn goals into activities while reasoning about future expected situations, an executive/diagnostics engine to initiate and maintain activities while interpreting sensed events by reasoning about past and present situations, and a conventional real-time subsystem to interface with the spacecraft to implement an activity's primitive actions. In addition to needing remote planning and execution for isolated spacecraft, a trend toward multiple-spacecraft missions points to the need for remote distributed planning and execution. The past few years have seen missions with growing numbers of probes. Pathfinder has its rover (Sojourner), Cassini has its lander (Huygens), and the New Millenium Deep Space 3 (DS3) proposal involves a constellation of 3 spacecraft for interferometric mapping. This trend is expected to continue to progressively larger fleets. For

  14. β Cephei and Slowly Pulsating B stars as targets for BRITE- Constellation

    NASA Astrophysics Data System (ADS)

    Handler, G.

    2008-01-01

    We discuss the potential of BRITE-Constellation for asteroseismology of main sequence B-type pulsators. We briefly review previous asteroseismic work on these oscillators and point out the importance of these stars for astrophysics in general. We find that BRITE-Constellation is ideally suited for studying B-type pulsators, and we identify several interesting regions in the sky that may be observed.

  15. Transformation abrogates an early G1-phase arrest point required for specification of the Chinese hamster DHFR replication origin.

    PubMed

    Wu, J R; Keezer, S M; Gilbert, D M

    1998-03-16

    The origin decision point (ODP) was originally identified as a distinct point during G1-phase when Chinese hamster ovary (CHO) cell nuclei experience a transition that is required for specific recognition of the dihydrofolate reductase (DHFR) origin locus by Xenopus egg extracts. Passage of cells through the ODP requires a mitogen-independent protein kinase that is activated prior to restriction point control. Here we show that inhibition of an early G1-phase protein kinase pathway by the addition of 2-aminopurine (2-AP) prior to the ODP arrests CHO cells in G1-phase. Transformation with simian virus 40 (SV40) abrogated this arrest point, resulting in the entry of cultured cells into S-phase in the presence of 2-AP and a disruption of the normal pattern of initiation sites at the DHFR locus. Cells treated with 2-AP after the ODP initiated replication specifically within the DHFR origin locus. Transient exposure of transformed cells to 2-AP during the ODP transition also disrupted origin choice, whereas non-transformed cells arrested in G1-phase and then passed through a delayed ODP after removal of 2-AP from the medium. We conclude that mammalian cells have many potential sites at which they can initiate replication. Normally, events occurring during the early G1-phase ODP transition determine which of these sites will be the preferred initiation site. However, if chromatin is exposed to S-phase-promoting factors prior to this transition, mammalian cells, like Xenopus and Drosophila embryos, can initiate replication without origin specification.

  16. Transformation abrogates an early G1-phase arrest point required for specification of the Chinese hamster DHFR replication origin.

    PubMed Central

    Wu, J R; Keezer, S M; Gilbert, D M

    1998-01-01

    The origin decision point (ODP) was originally identified as a distinct point during G1-phase when Chinese hamster ovary (CHO) cell nuclei experience a transition that is required for specific recognition of the dihydrofolate reductase (DHFR) origin locus by Xenopus egg extracts. Passage of cells through the ODP requires a mitogen-independent protein kinase that is activated prior to restriction point control. Here we show that inhibition of an early G1-phase protein kinase pathway by the addition of 2-aminopurine (2-AP) prior to the ODP arrests CHO cells in G1-phase. Transformation with simian virus 40 (SV40) abrogated this arrest point, resulting in the entry of cultured cells into S-phase in the presence of 2-AP and a disruption of the normal pattern of initiation sites at the DHFR locus. Cells treated with 2-AP after the ODP initiated replication specifically within the DHFR origin locus. Transient exposure of transformed cells to 2-AP during the ODP transition also disrupted origin choice, whereas non-transformed cells arrested in G1-phase and then passed through a delayed ODP after removal of 2-AP from the medium. We conclude that mammalian cells have many potential sites at which they can initiate replication. Normally, events occurring during the early G1-phase ODP transition determine which of these sites will be the preferred initiation site. However, if chromatin is exposed to S-phase-promoting factors prior to this transition, mammalian cells, like Xenopus and Drosophila embryos, can initiate replication without origin specification. PMID:9501102

  17. The CEOS constellation for land surface imaging

    USGS Publications Warehouse

    Bailey, G.B.; Berger, M.; Jeanjean, H.; Gallo, K.P.

    2007-01-01

    A constellation of satellites that routinely and frequently images the Earth's land surface in consistently calibrated wavelengths from the visible through the microwave and in spatial detail that ranges from sub-meter to hundreds of meters would offer enormous potential benefits to society. A well-designed and effectively operated land surface imaging satellite constellation could have great positive impact not only on the quality of life for citizens of all nations, but also on mankind's very ability to sustain life as we know it on this planet long into the future. The primary objective of the Committee on Earth Observation Satellites (CEOS) Land Surface Imaging (LSI) Constellation is to define standards (or guidelines) that describe optimal future LSI Constellation capabilities, characteristics, and practices. Standards defined for a LSI Constellation will be based on a thorough understanding of user requirements, and they will address at least three fundamental areas of the systems comprising a Land Surface Imaging Constellation: the space segments, the ground segments, and relevant policies and plans. Studies conducted by the LSI Constellation Study Team also will address current and shorter-term problems and issues facing the land remote sensing community today, such as seeking ways to work more cooperatively in the operation of existing land surface imaging systems and helping to accomplish tangible benefits to society through application of land surface image data acquired by existing systems. 2007 LSI Constellation studies are designed to establish initial international agreements, develop preliminary standards for a mid-resolution land surface imaging constellation, and contribute data to a global forest assessment.

  18. Time distributions in satellite constellation design

    NASA Astrophysics Data System (ADS)

    Arnas, David; Casanova, Daniel; Tresaco, Eva

    2017-01-01

    The aim of the time distribution methodology presented in this paper is to generate constellations whose satellites share a set of relative trajectories in a given time, and maintain that property over time without orbit corrections. The model takes into account a series of orbital perturbations such as the gravitational potential of the Earth, the atmospheric drag, the Sun and the Moon as disturbing third bodies and the solar radiation pressure. These perturbations are included in the design process of the constellation. Moreover, the whole methodology allows to design constellations with multiple relative trajectories that can be distributed in a minimum number of inertial orbits.

  19. Multifeature distortion-insensitive constellation detection.

    PubMed

    Casey, Charles; Hassebrook, Laurence G; Crane, Eli; Davidson, Aaron

    2011-04-20

    Many applications require detection of multiple features that locally remain consistent in shape and intensity characteristics, but may globally change position with respect to one another over time or under different circumstances. We refer to these feature sets, defined by their characteristic relative positioning, as multifeature constellations. We introduce a method of processing in which multiple levels of correlation, using specially designed composite feature detection filters, are used to first detect local features, and then to detect constellations of these local features. We include experimental procedures and results indicating how the use of multifeature constellation detection may be utilized in applications such as sign language recognition and fingerprint matching.

  20. Time distributions in satellite constellation design

    NASA Astrophysics Data System (ADS)

    Arnas, David; Casanova, Daniel; Tresaco, Eva

    2017-06-01

    The aim of the time distribution methodology presented in this paper is to generate constellations whose satellites share a set of relative trajectories in a given time, and maintain that property over time without orbit corrections. The model takes into account a series of orbital perturbations such as the gravitational potential of the Earth, the atmospheric drag, the Sun and the Moon as disturbing third bodies and the solar radiation pressure. These perturbations are included in the design process of the constellation. Moreover, the whole methodology allows to design constellations with multiple relative trajectories that can be distributed in a minimum number of inertial orbits.

  1. Distortion-insensitive correlation constellation detection

    NASA Astrophysics Data System (ADS)

    Casey, Charles; Hassebrook, Laurence G.; Crane, Eli; Davidson, Aaron

    2011-04-01

    There are applications that require detection of multiple features which remain consistent in shape locally, but may change position with respect to one another globally. We refer to these feature sets as multi-feature constellations. We introduce a multi-level correlation filter design which uses composite feature detection filters, which on one level detect local features, and then on the next level detect constellations of these local feature responses. We demonstrate the constellation filter method with sign language recognition and fingerprint matching.

  2. The 50 Constellation Priority Sites

    NASA Technical Reports Server (NTRS)

    Noble, S.; Joosten, K.; Eppler, D.; Gruener, J.; Mendell, W.; French, R.; Plescia, J.; Spudis, P.; Wargo, M.; Robinson, M.; Lucey, P.

    2009-01-01

    The Constellation program (CxP) has developed a list of 50 sites of interest on the Moon which will be targeted by the LRO narrow angle camera. The list has also been provided to the M team to supplement their targeting list. This list does not represent a "site selection" process; rather the goal was to find "representative" sites and terrains to understand the range of possible surface conditions for human lunar exploration to aid engineering design and operational planning. The list compilers leveraged heavily on past site selection work (e.g. Geoscience and a Lunar Base Workshop - 1988, Site Selection Strategy for a Lunar Outpost - 1990, Exploration Systems Architecture Study (ESAS) - 2005). Considerations included scientific, resource utilization, and operational merits, and a desire to span lunar terrain types. The targets have been organized into two "tiers" of 25 sites each to provide a relative priority ranking in the event of mutual interference. A LEAG SAT (special action team) was established to validate and recommend modifications to the list. This SAT was chaired by Dr. Paul Lucey. They provided their final results to CxP in May. Dr. Wendell Mendell will organize an on-going analysis of the data as they come down to ensure data quality and determine if and when a site has sufficient data to be retired from the list. The list was compiled using the best available data, however, it is understood that with the flood of new lunar data, minor modifications or adjustments may be required.

  3. Stem cell research points the way to the cell of origin for intracranial germ cell tumours.

    PubMed

    Tan, Chris; Scotting, Paul J

    2013-01-01

    Germ cell tumours found in the brain (intracranial GCTs) are a very unusual class of tumour for two reasons. First, they include a very diverse range of histological subtypes classified together due to their proposed common cell of origin. Second, this proposed cell of origin, the germ cell progenitor, would not normally be found in the tissue where these tumours arise. This is in contrast to all other primary brain tumours, in which the cell of origin is believed to be a brain cell. Indeed, no other class of primary cancer arises from a cell from a distant organ. This theory for the origins of intracranial GCTs has been in place for many decades, but recent data arising from studies of induced pluripotency for regenerative medicine raise serious questions about this dogma. Here we review the cellular origins of intracranial GCTs in the light of these new data and reanalyse the existing data on the biology of this unusual class of tumours. Together, these considerations lead us to conclude that the evidence now falls in favour of a model in which these tumours arise from the transformation of endogenous brain cells. This theory should inform future studies of the aetiology of these tumours and so lead the way to animal models in which to study their development and potential biological therapeutics. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

  4. An optimization solution of a laser plane in vision measurement with the distance object between global origin and calibration points

    PubMed Central

    Xu, Guan; Hao, Zhaobing; Li, Xiaotao; Su, Jian; Liu, Huanping; Sun, Lina

    2015-01-01

    Equation construction of a laser plane demonstrates a remarkable importance for vision measurement systems based on the structured light. Here we create a simple 1D target with a cone at the bottom and a checkered pattern on the top to calibrate the equation of the laser plane in the view field of a camera. A group of 2D coordinates of the intersection points are extracted from the images with the 1D target at different positions. The objective function is constructed to optimize the coefficients of the laser plane by minimizing the difference between the distance from the feature point to the the origin point and the length of the 1D target. The projective lines of the optimized laser plane on the 3D calibration board overlap the real intersection lines in the experimental images. Finally, the comparison work about the influences of the non-Gaussian noise and point number is investigated experimentally. The experiments show that the method of the distance optimal object from the feature point to the origin point provides an accurate and robust calibration for the laser plane in structured light measurement. PMID:26149292

  5. Approach to the origin of turbulence on the basis of two-point kinetic theory

    NASA Technical Reports Server (NTRS)

    Tsuge, S.

    1974-01-01

    Equations for the fluctuation correlation in an incompressible shear flow are derived on the basis of kinetic theory, utilizing the two-point distribution function which obeys the BBGKY hierarchy equation truncated with the hypothesis of 'ternary' molecular chaos. The step from the molecular to the hydrodynamic description is accomplished by a moment expansion which is a two-point version of the thirteen-moment method, and which leads to a series of correlation equations, viz., the two-point counterparts of the continuity equation, the Navier-Stokes equation, etc. For almost parallel shearing flows the two-point equation is separable and reduces to two Orr-Sommerfeld equations with different physical implications.

  6. Heavy metal origin and concentration in the sediments of the Pointe à Pitre bay (guadeloupe—lesser antilles

    NASA Astrophysics Data System (ADS)

    Castaing, P.; Assor, R.; Jouanneau, J. M.; Weber, O.

    1986-12-01

    Sewage discharge (chiefly waste waters into the Pointe à Pitre bay originates from the neighboring developing town (60,000 inhabitants) A sampling campaign carried out in March 1984 permitted the assessment of both water and sediment quality in the bay, as well as the evaulation of heavy metal contents Industrial pollution appears insignificant whilst urban pollution dominates. Heavy metal contents (lead (Pb), zinc (Zn), copper (Cu)) are high in the sediments of the inner end of the bay and eastern bank, parallel to the urban agglomeration. This anthropogenic origin is accounted for by comparison of heavy metal contents with those prevailing in the terrestrial environment

  7. Constellation Space Suit System Development Status

    NASA Technical Reports Server (NTRS)

    Ross, Amy; Aitchison, Lindsay; Daniel, Brian

    2007-01-01

    The Constellation Program has initiated the first new flight suit development project since the Extravehicular Mobility Unit (EMU) was developed for the Space Shuttle Program in the 1970s. The Constellation suit system represents a significant challenge to designers in that the system is required to address all space suit functions needed through all missions and mission phases. This is in marked contrast to the EMU, which was designed specifically for micro-gravity space walks. The Constellation suit system must serve in all of the following scenarios: launch, entry and abort crew survival; micro-gravity extravehicular activity (EVA); and lunar (1/6th-gravity) surface EVA. This paper discusses technical efforts performed from May 2006 through February 2007 for the Constellation space suit system pressure garment.

  8. EOS Terra: Mission Status Constellation MOWG

    NASA Technical Reports Server (NTRS)

    Mantziaras, Dimitrios

    2016-01-01

    This EOS Terra Mission Status Constellation MOWG will discuss mission summary; spacecraft subsystems summary, recent and planned activities; inclination adjust maneuvers, conjunction history, propellant usage and lifetime estimate; and end of mission plan.

  9. Multiple Autonomous Discrete Event Controllers for Constellations

    NASA Technical Reports Server (NTRS)

    Esposito, Timothy C.

    2003-01-01

    The Multiple Autonomous Discrete Event Controllers for Constellations (MADECC) project is an effort within the National Aeronautics and Space Administration Goddard Space Flight Center's (NASA/GSFC) Information Systems Division to develop autonomous positioning and attitude control for constellation satellites. It will be accomplished using traditional control theory and advanced coordination algorithms developed by the Johns Hopkins University Applied Physics Laboratory (JHU/APL). This capability will be demonstrated in the discrete event control test-bed located at JHU/APL. This project will be modeled for the Leonardo constellation mission, but is intended to be adaptable to any constellation mission. To develop a common software architecture. the controllers will only model very high-level responses. For instance, after determining that a maneuver must be made. the MADECC system will output B (Delta)V (velocity change) value. Lower level systems must then decide which thrusters to fire and for how long to achieve that (Delta)V.

  10. Cross Calibration of the Afternoon Constellation's

    NASA Image and Video Library

    The name "A-Train" comes from the formation of international, Earth-observing satellites known as the Afternoon Constellation, which operate in a Sun-synchronous orbit at an altitude of 705 km. The...

  11. Optimal Replacement Policies for Satellite Constellations

    DTIC Science & Technology

    2003-03-01

    satellite and booster inventory demands . The purpose of the Evaluate Launch Schedule function is to determine how many operational satellites will be... Markovian decision models . Operations Research, 13, 272-278. BIB-1 15. Ereau, J.-F. and M. Saleman (1996). Modeling & simulation of a satellite constel...2-1 2.1 Optimal Replacement Models . . . . . . . . . . . . . . 2-1 2.2 Satellite Constellation Models . . . . . . . . . . . . . . 2-6 3. Formal Model

  12. Determination of Earth outgoing radiation using a constellation of satellites

    NASA Astrophysics Data System (ADS)

    Gristey, Jake; Chiu, Christine; Gurney, Robert; Han, Shin-Chan; Morcrette, Cyril

    2017-04-01

    The outgoing radiation fluxes at the top of the atmosphere, referred to as Earth outgoing radiation (EOR), constitute a vital component of the Earth's energy budget. This EOR exhibits strong diurnal signatures and is inherently connected to the rapidly evolving scene from which the radiation originates, so our ability to accurately monitor EOR with sufficient temporal resolution and spatial coverage is crucial for weather and climate studies. Despite vast improvements in satellite observations in recent decades, achieving these criteria remains challenging from current measurements. A technology revolution in small satellites and sensor miniaturisation has created a new and exciting opportunity for a novel, viable and sustainable observation strategy from a constellation of satellites, capable of providing both global coverage and high temporal resolution simultaneously. To explore the potential of a constellation approach for observing EOR we perform a series of theoretical simulation experiments. Using the results from these simulation experiments, we will demonstrate a baseline constellation configuration capable of accurately monitoring global EOR at unprecedented temporal resolution. We will also show whether it is possible to reveal synoptic scale, fast evolving phenomena by applying a deconvolution technique to the simulated measurements. The ability to observe and understand the relationship between these phenomena and changes in EOR is of fundamental importance in constraining future warming of our climate system.

  13. On constellation design of multi-GNSS radio occultation mission

    NASA Astrophysics Data System (ADS)

    Juang, Jyh-Ching; Tsai, Yung-Fu; Chu, Chung-Huei

    2013-01-01

    The FORMOSAT-3/COSMIC mission which is a joint Taiwan-US mission for meteorological, climatological, ionospheric, and geodetic studies has successfully provided a significant amount of GPS radio occultation (RO) data for better modeling of climate model, forecasting of weather, and monitoring of ionosphere. Owing to the success of the FORMOSAT-3 program, the follow-on FORMOSAT-7 mission is being planned. In the perceivable future, sources for RO mission can be originated from multiple global navigation satellite systems (GNSSs) including GPS, Galileo, GLONASS, and Beidou as well as several regional navigation satellite systems (RNSSs) and space-based augmentation systems (SBASs). To facilitate the operational capability for weather forecast and space weather monitoring, the FORMOSAT-7 constellation must be designed to ensure a sufficient and uniform distribution in space and time for GNSS/RNSS/SBAS RO events. In addition, it is desired that the RO events in certain region can be maximized to account for severe weather. As the distribution of RO events due to GNSS, RNSS, and SBAS are distinct and the requirements appear to be multi-objective, the constellation design becomes very complicated. The paper applies genetic algorithm (GA) to design constellation parameters. It is shown that the adopted approach can be used to account for non-uniform distribution of RO events due to RNSSs and SBASs. The GA-based design approach is demonstrated to result in constellations that are superior in both global distribution and regional emphasis of RO events to those of the existing baseline design.

  14. 78 FR 32385 - Exelon Generation Company, LLC; CER Generation II, LLC; Constellation Mystic Power, LLC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-30

    ... Energy Regulatory Commission Exelon Generation Company, LLC; CER Generation II, LLC; Constellation Mystic Power, LLC; Constellation NewEnergy, Inc.; Constellation Power Source Generation, Inc.; Criterion Power..., CER Generation II, LLC, Constellation Mystic Power, LLC, Constellation NewEnergy, Inc.,...

  15. Sex and ethnic-origin specific BMI cut points improve prediction of 40-year mortality: the Israel GOH study.

    PubMed

    Dankner, Rachel; Shanik, Michael; Roth, Jesse; Luski, Ayala; Lubin, Flora; Chetrit, Angela

    2015-07-01

    Although obesity has been associated with a higher risk for premature death, the sex and ethnic-origin specific body mass index (BMI) levels that are associated with increased mortality are controversial. We investigated the 40-year cumulative all-cause mortality, in relation to the BMI in adult life, among men and women originating from Yemen, Europe/America, Middle East and North Africa, using sex and ethnic-origin specific BMI cut points. A random stratified cohort (n = 5710) was sampled from the central population registry and followed since 1969 for vital status. Weight, height and blood pressure were measured, and smoking status was recorded at baseline. BMI was analysed according to conventional categories and according to sex and ethnic-origin specific quintiles. Elevated and significant mortality hazard ratios (HRs) of 1.21 [95% confidence interval (CI) 1.00-1.45] for women and 1.22 (95%CI 1.03-1.44) for men were found for the highest origin-specific BMI quintile. In men, the lowest ethnic-origin specific quintile was also significantly associated with increased mortality (HR of 1.22 95% CI 1.03-1.45), adjusting for age, smoking and blood pressure. Obesity was associated with mortality in non-smokers (HR = 1.29, 95% CI 1.04-1.61 in men and HR = 1.46, 95% CI 1.19-1.79 in women), whereas leanness was associated with mortality only among smoking men (HR = 1.39, 95% CI 1.09-1.77). Refinement of BMI categories using country of origin specific quintiles demonstrated significantly increased mortality in the upper quintile in both sexes, while according to the conventional values this association did not prevail in men. We propose the establishment of sex and origin-specific BMI categories when setting goals for disease prevention. Copyright © 2015 John Wiley & Sons, Ltd.

  16. Chimpanzee vocal signaling points to a multimodal origin of human language.

    PubMed

    Taglialatela, Jared P; Russell, Jamie L; Schaeffer, Jennifer A; Hopkins, William D

    2011-04-20

    The evolutionary origin of human language and its neurobiological foundations has long been the object of intense scientific debate. Although a number of theories have been proposed, one particularly contentious model suggests that human language evolved from a manual gestural communication system in a common ape-human ancestor. Consistent with a gestural origins theory are data indicating that chimpanzees intentionally and referentially communicate via manual gestures, and the production of manual gestures, in conjunction with vocalizations, activates the chimpanzee Broca's area homologue--a region in the human brain that is critical for the planning and execution of language. However, it is not known if this activity observed in the chimpanzee Broca's area is the result of the chimpanzees producing manual communicative gestures, communicative sounds, or both. This information is critical for evaluating the theory that human language evolved from a strictly manual gestural system. To this end, we used positron emission tomography (PET) to examine the neural metabolic activity in the chimpanzee brain. We collected PET data in 4 subjects, all of whom produced manual communicative gestures. However, 2 of these subjects also produced so-called attention-getting vocalizations directed towards a human experimenter. Interestingly, only the two subjects that produced these attention-getting sounds showed greater mean metabolic activity in the Broca's area homologue as compared to a baseline scan. The two subjects that did not produce attention-getting sounds did not. These data contradict an exclusive "gestural origins" theory for they suggest that it is vocal signaling that selectively activates the Broca's area homologue in chimpanzees. In other words, the activity observed in the Broca's area homologue reflects the production of vocal signals by the chimpanzees, suggesting that this critical human language region was involved in vocal signaling in the common ancestor

  17. Origin of melting point depression for rare gas solids confined in carbon pores

    NASA Astrophysics Data System (ADS)

    Morishige, Kunimitsu; Kataoka, Takaaki

    2015-07-01

    To obtain insights into the mechanism of the melting-point depression of rare gas solids confined in crystalline carbon pores, we examined the freezing and melting behavior of Xe and Ar confined to the crystalline pores of ordered mesoporous carbons as well as compressed exfoliated graphite compared to the amorphous pores of ordered mesoporous silicas, by means of X-ray diffraction. For the Xe and Ar confined to the crystalline carbon pores, there was no appreciable thermal hysteresis between freezing and melting. Furthermore, the position of the main diffraction peak did not change appreciably on freezing and melting. This strongly suggests that the liquids confined in the carbon pores form a multilayered structure parallel to the smooth walls. For the Xe and Ar confined to the amorphous silica pores, on the other hand, the position of the main diffraction peak shifted into higher scattering angle on freezing suggested that the density of the confined solid is distinctly larger than for the confined liquid. Using compressed exfoliated graphite with carbon walls of higher crystallinity, we observed that three-dimensional (3D) microcrystals of Xe confined in the slit-shaped pores melted to leave the unmelted bilayers on the pore walls below the bulk triple point. The lattice spacing of the 3D microcrystals confined is larger by ˜0.7% than that of the bilayer next to the pore walls in the vicinity of the melting point.

  18. Origin of melting point depression for rare gas solids confined in carbon pores

    SciTech Connect

    Morishige, Kunimitsu Kataoka, Takaaki

    2015-07-21

    To obtain insights into the mechanism of the melting-point depression of rare gas solids confined in crystalline carbon pores, we examined the freezing and melting behavior of Xe and Ar confined to the crystalline pores of ordered mesoporous carbons as well as compressed exfoliated graphite compared to the amorphous pores of ordered mesoporous silicas, by means of X-ray diffraction. For the Xe and Ar confined to the crystalline carbon pores, there was no appreciable thermal hysteresis between freezing and melting. Furthermore, the position of the main diffraction peak did not change appreciably on freezing and melting. This strongly suggests that the liquids confined in the carbon pores form a multilayered structure parallel to the smooth walls. For the Xe and Ar confined to the amorphous silica pores, on the other hand, the position of the main diffraction peak shifted into higher scattering angle on freezing suggested that the density of the confined solid is distinctly larger than for the confined liquid. Using compressed exfoliated graphite with carbon walls of higher crystallinity, we observed that three-dimensional (3D) microcrystals of Xe confined in the slit-shaped pores melted to leave the unmelted bilayers on the pore walls below the bulk triple point. The lattice spacing of the 3D microcrystals confined is larger by ∼0.7% than that of the bilayer next to the pore walls in the vicinity of the melting point.

  19. Origin of melting point depression for rare gas solids confined in carbon pores.

    PubMed

    Morishige, Kunimitsu; Kataoka, Takaaki

    2015-07-21

    To obtain insights into the mechanism of the melting-point depression of rare gas solids confined in crystalline carbon pores, we examined the freezing and melting behavior of Xe and Ar confined to the crystalline pores of ordered mesoporous carbons as well as compressed exfoliated graphite compared to the amorphous pores of ordered mesoporous silicas, by means of X-ray diffraction. For the Xe and Ar confined to the crystalline carbon pores, there was no appreciable thermal hysteresis between freezing and melting. Furthermore, the position of the main diffraction peak did not change appreciably on freezing and melting. This strongly suggests that the liquids confined in the carbon pores form a multilayered structure parallel to the smooth walls. For the Xe and Ar confined to the amorphous silica pores, on the other hand, the position of the main diffraction peak shifted into higher scattering angle on freezing suggested that the density of the confined solid is distinctly larger than for the confined liquid. Using compressed exfoliated graphite with carbon walls of higher crystallinity, we observed that three-dimensional (3D) microcrystals of Xe confined in the slit-shaped pores melted to leave the unmelted bilayers on the pore walls below the bulk triple point. The lattice spacing of the 3D microcrystals confined is larger by ∼0.7% than that of the bilayer next to the pore walls in the vicinity of the melting point.

  20. New interpretation of the ancient constellations

    NASA Astrophysics Data System (ADS)

    Dementev, M. S.

    New method of study of the ancient constellations and mythes is discussed. It is based on the comparison of two maps - the sky and the Earth. The Stellar map is built in an equatorial system of coordinates, the geografic map - in the Mercator's projection and of the same scale. The former map is put on the laster one. The constellation of Pleiades (seven daughter of Atlant) is placed on the meridian of Atlant (Western coast of Africa). If the Stellar map is constructed for a epoch J-3000 (3000 years up to B.C.) then we could found the following. The constellations Andromeda (the daughter of the Ethiopian tsar), Cetus, Perseus and Cassiopeia (mother of Andromeda) are projected on the centre, south and west of Ancient Ethiopia and Mediterranean Sea, respectively. That is all the constellations fall to the places, where events described in mythes occured. A constellation Cepheus (Arabian name is "Burning") covers the Caucasus. Possibly, before a epoch J-1000 this group of stars was connected with Prometheus. It is known Prometheus was chained to the Caucasian rock because of stealing of a fire. Ancient Chineses divided the sky in other way. They called "The Heavenly Town" the area of sky consisting of stars in Herculis, Aquilae and Ophiuchi. Parts of the mentioned constellation were called as a provinces in Ancient China. If the Heavenly Town locate near the Ancient China then the Greek constellations (Andromeda, Perseus and Cetus) will appear over Africa. Three important conclusions follow from this: (i) the geography of the Earth is reflected on the sky; (ii) the ancient astronomers were investigating a connection between the sky and Earth; (iii) the ancient peoples exchanged by the information about a construction of the world.

  1. Origins.

    PubMed

    Weinberg, S

    1985-10-04

    The farthest of the galaxies that can be seen through the large ground-based telescopes of modern astronomy, such as those on La Palma in the Canary Islands, are so far away that they appear as they did close to the time of the origin of the universe, perhaps some 10 billion years ago. Much has been learned, and much has still to be learned, about the young universe from optical and radio telescopes, but these instruments cannot be used to look directly at the universe in its first few hundred thousand years. Instead, they are used to search the relatively recent past for relics of much earlier times. Together with experiments planned for the next generation of elementary particle accelerators, astronomical observations should continue to extend what is known about the universe backward in time to the Big Bang and may eventually help to reveal the origins of the physical laws that govern the universe.

  2. Origin of steep-pointed and flat-topped volcanic cones in Southwest volcanic field

    NASA Astrophysics Data System (ADS)

    Fukui, U.; Hirota, F.; Yokose, H.

    2002-12-01

    KR01-12 cruise of Japan Marine Science and Technology Center using ROV KAIKO and its mother ship R/V KAIREI were carried out around Hawaii islands in the early fall of 2001. During this cruise, two dives of ROV KAIKO were made on southwest Oahu volcanic field (K203 and K206).The new Seabeam bathymetry revealed that there are remarkable topographic features: flat-topped volcanic cone, ca.2.5 in diameter and 200m in height; steep pointed cone, ellipsoidal in plain: major axis 2km, minor axis 0.5km; 200-400 m in height. This volcanic topographies are similar to those described in elsewhere e.g., Clague et al., 2001. Flat-topped cones distributed in this area are different from other area in their occurrence. They are accompanied with steep-pointed cone. In order to study the geological and petrological relationship between flat-topped cone and steep-pointed cone, both K203 and K206 have been analyzed by video image, thin sections and bulk rock chemistry. The rocks recovered from K206 and K203 are trachybasalt and basanite respectibly. There is no critical differences between FTVC and SPVCin their bulk chemistry. For example rocks from FTCV are almost identical to the SPCV in SiO2 contents in the same site. Total AK concentration of rocks from FTCV is lower than those of SPVC in K203, but FTVC is higher than SPCV in K206. This result implies that topographical characters are not correlated with bulk chemistry. Both in K206 or K203, rocks collected from SPVC have higher vesicularity, ranging from 20 to 40%, and higher crystallinity in groundmass than those from FTCV. It is suggest that differences in topographical characteristics between FTVC and SPVC are controlled by physical property of the groundmass. That is, the viscosity of magma lead to rise due to exsolution of gas phase from melt.

  3. Science Opportunities Enabled by NASA's Constellation System: Interim Report

    NASA Technical Reports Server (NTRS)

    2008-01-01

    In 2004 NASA initiated studies of advanced science mission concepts known as the Vision Missions and inspired by a series of NASA roadmap activities conducted in 2003. Also in 2004 NASA began implementation of the first phases of a new space exploration policy, the Vision for Space Exploration. This implementation effort included development of a new human-carrying spacecraft, known as Orion, and two new launch vehicles, the Ares I and Ares V rockets.collectively called the Constellation System. NASA asked the National Research Council (NRC) to evaluate the science opportunities enabled by the Constellation System (see Preface) and to produce an interim report on a short time schedule and a final report by November 2008. The committee notes, however, that the Constellation System and its Orion and Ares vehicles have been justified by NASA and selected in order to enable human exploration beyond low Earth orbit, and not to enable science missions. This interim report of the Committee on Science Opportunities Enabled by NASA s Constellation System evaluates the 11 Vision Mission studies presented to it and groups them into two categories: those more deserving of future study, and those less deserving of future study. Although its statement of task also refers to Earth science missions, the committee points out that the Vision Missions effort was focused on future astronomy, heliophysics, and planetary exploration and did not include any Earth science studies because, at the time, the NRC was conducting the first Earth science decadal survey, and funding Earth science studies as part of the Vision Missions effort would have interfered with that process. Consequently, no Earth science missions are evaluated in this interim report. However, the committee will evaluate any Earth science mission proposal submitted in response to its request for information issued in March 2008 (see Appendix A). The committee based its evaluation of the preexisting Vision Missions studies

  4. Science Opportunities Enabled by NASA's Constellation System: Interim Report

    NASA Technical Reports Server (NTRS)

    2008-01-01

    In 2004 NASA initiated studies of advanced science mission concepts known as the Vision Missions and inspired by a series of NASA roadmap activities conducted in 2003. Also in 2004 NASA began implementation of the first phases of a new space exploration policy, the Vision for Space Exploration. This implementation effort included development of a new human-carrying spacecraft, known as Orion, and two new launch vehicles, the Ares I and Ares V rockets.collectively called the Constellation System. NASA asked the National Research Council (NRC) to evaluate the science opportunities enabled by the Constellation System (see Preface) and to produce an interim report on a short time schedule and a final report by November 2008. The committee notes, however, that the Constellation System and its Orion and Ares vehicles have been justified by NASA and selected in order to enable human exploration beyond low Earth orbit, and not to enable science missions. This interim report of the Committee on Science Opportunities Enabled by NASA s Constellation System evaluates the 11 Vision Mission studies presented to it and groups them into two categories: those more deserving of future study, and those less deserving of future study. Although its statement of task also refers to Earth science missions, the committee points out that the Vision Missions effort was focused on future astronomy, heliophysics, and planetary exploration and did not include any Earth science studies because, at the time, the NRC was conducting the first Earth science decadal survey, and funding Earth science studies as part of the Vision Missions effort would have interfered with that process. Consequently, no Earth science missions are evaluated in this interim report. However, the committee will evaluate any Earth science mission proposal submitted in response to its request for information issued in March 2008 (see Appendix A). The committee based its evaluation of the preexisting Vision Missions studies

  5. Structural origin underlying the effect of cooling rate on solidification point

    NASA Astrophysics Data System (ADS)

    Li, Chen-Hui; Han, Xiu-Jun; Luan, Ying-Wei; Li, Jian-Guo

    2015-11-01

    Solidification behaviors of liquid aluminum at different cooling rates were examined via classical molecular dynamics simulation with an embedded atom method potential. The results demonstrate that solidification point decreases with increasing cooling rate. To explain this phenomenon, solid-like cluster in liquid was analyzed by the structural analysis method of bond order parameters. The results reveal that the size of the largest solid-like cluster in deeply undercooled liquid decreases with the increase of cooling rate, which can provide a structural interpretation to the above phenomenon. Project supported by the National Basic Research Program of China (Grant No. 2011CB012900), the National Natural Science Foundation of China (Grant No. 51171115), the Natural Science Foundation of Shanghai City, China (Grant No. 10ZR1415700), the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20100073120008), the Program for New Century Excellent Talents in Universities of China. This work is partially supported by Alexander von Humboldt Foundation.

  6. On the origin of dislocation loops in irradiated materials: A point of view from silicon

    NASA Astrophysics Data System (ADS)

    Claverie, Alain; Cherkashin, Nikolay

    2016-05-01

    Numerous dislocation loops are often observed in irradiated and nuclear materials, affecting many physical properties. The understanding of their origin and of their growth mechanism remains unclear rendering all modeling efforts elusive. In this paper, we remind the knowledge which has been gained during the last 20 years on the formation and growth of extrinsic dislocations loops in irradiated/implanted silicon. From the compilation of a large number of experimental results, a unified picture describing the thermal evolution of interstitial defects, from the di-interstitial stable at room temperature, to ;magic-size; clusters then to rod-like defects and finally to large dislocation loops of two types has emerged. All these defects grow by Ostwald ripening, i.e. by interchanging the interstitial atoms they are composed of, and transform from one to the other driven by the resulting reduction of the defect formation energy. A model has been proposed and is now integrated into process simulators which quantitatively describes the thermal evolution of all these defects, based on pertinent formation energies. The influence of the proximity of free surfaces or other recombining interfaces can be integrated, allowing simulating the possible dissolution of defects. It is suggested that, beyond silicon, the same type of scenario may take place in many materials. Dislocation loops are just one, easily detectable among many, type of defects which forms during the growth of self-interstitials. They do not nucleate but result from the growth and transformation of smaller defects.

  7. Integration of Point Clouds Originated from Laser Scaner and Photogrammetric Images for Visualization of Complex Details of Historical Buildings

    NASA Astrophysics Data System (ADS)

    Altuntas, C.

    2015-02-01

    Three-dimensional (3D) models of historical buildings are created for documentation and virtual realization of them. Laser scanning and photogrammetry are extensively used to perform for these aims. The selection of the method that will be used in threedimensional modelling study depends on the scale and shape of the object, and also applicability of the method. Laser scanners are high cost instruments. However, the cameras are low cost instruments. The off-the-shelf cameras are used for taking the photogrammetric images. The camera is imaging the object details by carrying on hand while the laser scanner makes ground based measurement. Laser scanner collect high density spatial data in a short time from the measurement area. On the other hand, image based 3D (IB3D) measurement uses images to create 3D point cloud data. The image matching and the creation of the point cloud can be done automatically. Historical buildings include more complex details. Thus, all details cannot be measured by terrestrial laser scanner (TLS) due to the blocking the details with each others. Especially, the artefacts which have complex shapes cannot be measured in full details. They cause occlusion on the point cloud model. However it is possible to record photogrammetric images and creation IB3D point cloud for these areas. Thus the occlusion free 3D model is created by the integration of point clouds originated from the TLS and photogrammetric images. In this study, usability of laser scanning in conjunction with image based modelling for creation occlusion free three-dimensional point cloud model of historical building was evaluated. The IB3D point cloud was created in the areas that could not been measured by TLS. Then laser scanning and IB3D point clouds were integrated in the common coordinate system. The registration point clouds were performed with the iterative closest point (ICP) and georeferencing methods. Accuracy of the registration was evaluated by convergency and its

  8. Visibility and geometry of Galileo constellations

    NASA Astrophysics Data System (ADS)

    Januszewski, Jacek

    Nowadays there are two worldwide satellite navigation systems - American GPS and Russian GLONASS. A new system - Galileo will be constructed in Europe. The most probable numbers of visible satellites above a certain limit, a masking elevation angle Hmin for Galileo system at different latitude of the observer and relevant distributions of GDOP (Geometric Dilution Of Precision) coefficient values (in per cent, over 8 intervals), were calculated and presented in this paper. The calculations were realized for the two most possible Galileo constellations (MEO only) of 27 or 30 satellites distributed in three planes. Elevation Hmin was assumed to 0°, 5°, 10° and 15°. The interval of latitude of the observer from 0° to 90° was divided into 9 zones, each 10° wide. As the number of satellites used for pseudorange measurements can be less than the number of satellites visible at a given moment and certain point on the Earth (for many reasons), additional calculations were realized for assumption of 1, 2 or 3 non operational satellites. All calculations, based upon the reference ellipsoid WGS-84, were made with the use of the author's simulating program. Random-number generator with uniform distribution generated the geographic and time coordinates of the observer. As the possibility of fix position depends on the relative position of the satellites in the orbits the calculations were made for different combinations. As the results we can say the position of observer in mode "3D" can be obtained for Hmin ≤ 15° in each zone.

  9. Diverse origins of Arctic and Subarctic methane point source emissions identified with multiply-substituted isotopologues

    NASA Astrophysics Data System (ADS)

    Douglas, P. M. J.; Stolper, D. A.; Smith, D. A.; Walter Anthony, K. M.; Paull, C. K.; Dallimore, S.; Wik, M.; Crill, P. M.; Winterdahl, M.; Eiler, J. M.; Sessions, A. L.

    2016-09-01

    Methane is a potent greenhouse gas, and there are concerns that its natural emissions from the Arctic could act as a substantial positive feedback to anthropogenic global warming. Determining the sources of methane emissions and the biogeochemical processes controlling them is important for understanding present and future Arctic contributions to atmospheric methane budgets. Here we apply measurements of multiply-substituted isotopologues, or clumped isotopes, of methane as a new tool to identify the origins of ebullitive fluxes in Alaska, Sweden and the Arctic Ocean. When methane forms in isotopic equilibrium, clumped isotope measurements indicate the formation temperature. In some microbial methane, however, non-equilibrium isotope effects, probably related to the kinetics of methanogenesis, lead to low clumped isotope values. We identify four categories of emissions in the studied samples: thermogenic methane, deep subsurface or marine microbial methane formed in isotopic equilibrium, freshwater microbial methane with non-equilibrium clumped isotope values, and mixtures of deep and shallow methane (i.e., combinations of the first three end members). Mixing between deep and shallow methane sources produces a non-linear variation in clumped isotope values with mixing proportion that provides new constraints for the formation environment of the mixing end-members. Analyses of microbial methane emitted from lakes, as well as a methanol-consuming methanogen pure culture, support the hypothesis that non-equilibrium clumped isotope values are controlled, in part, by kinetic isotope effects induced during enzymatic reactions involved in methanogenesis. Our results indicate that these kinetic isotope effects vary widely in microbial methane produced in Arctic lake sediments, with non-equilibrium Δ18 values spanning a range of more than 5‰.

  10. The NASA Constellation Program Procedure System

    NASA Technical Reports Server (NTRS)

    Phillips, Robert G.; Wang, Lui

    2010-01-01

    NASA has used procedures to describe activities to be performed onboard vehicles by astronaut crew and on the ground by flight controllers since Apollo. Starting with later Space Shuttle missions and the International Space Station, NASA moved forward to electronic presentation of procedures. For the Constellation Program, another large step forward is being taken - to make procedures more interactive with the vehicle and to assist the crew in controlling the vehicle more efficiently and with less error. The overall name for the project is the Constellation Procedure Applications Software System (CxPASS). This paper describes some of the history behind this effort, the key concepts and operational paradigms that the work is based upon, and the actual products being developed to implement procedures for Constellation

  11. Science with the constellation-X observatory

    SciTech Connect

    Valinia, Azita; White, Nicholas; Tananbaum, Harvey

    1999-04-27

    The Constellation X-ray Mission is a high throughput X-ray facility emphasizing observations at high spectral resolution (E/{delta}E{approx}300-3000), and broad energy bandpass (0.25-40 keV). Constellation-X will provide a factor of nearly 100 increase in sensitivity over current high resolution X-ray spectroscopy missions. It is the X-ray astronomy equivalent of large ground-based optical telescopes such as the Keck Observatory and the ESO Very Large Telescope. When observations commence toward the end of next decade, Constellation-X will address many fundamental astrophysics questions such as: the formation and evolution of clusters of galaxies; constraining the baryon content of the Universe; determining the spin and mass of supermassive black holes in AGN; and probing strong gravity in the vicinity of black holes.

  12. The Earth Science Afternoon Constellation Contingency Procedures

    NASA Technical Reports Server (NTRS)

    Case, Warren F.; Richon, Karen

    2005-01-01

    The Earth Science Afternoon Constellation comprises NASA missions Aqua, Aura, CloudSat and the Orbiting Carbon Observatory (OCO), the joint NASA/CNES mission CALIPSO and the CNES mission PARASOL. Both NASA and CNES offices are responsible for ensuring that contingency plans or other arrangements exist to cope with contingencies within their respective jurisdictions until the conclusion of all Afternoon Constellation operations. The Mission Operations Working Group, comprised of members from each of the missions, has developed the high-level procedures for maintaining the safety of this constellation. Each contingency situation requires detailed analyses before any decisions are made. This paper describes these procedures, and includes defining what constitutes a contingency situation, the pertinent parameters involved in the contingency analysis and guidelines for the actions required, based on the results of the contingency analyses.

  13. Motherhood constellation and representational change in pregnancy.

    PubMed

    Innamorati, Marco; Sarracino, Diego; Dazzi, Nino

    2010-07-01

    The main aim of this study was to explore the prevalence and development of the motherhood constellation in pregnant women. The participants of the study were 162 pregnant women who were divided into three subgroups according to their gestation period (<6 months, 6-7 months, >7 months). The women were assessed using the Breakfast Interview, a microanalytic method devised by D.N. Stern (1995, 2004a). Two judges coded the transcripts of the interviews for the presence of the motherhood constellation themes using three-level rating scales. Results showed that the Life/Growth theme was the most frequent theme during pregnancy, and supported the hypothesis of a "peak" of the motherhood constellation themes around Month 6 to Month 7. Copyright © 2010 Michigan Association for Infant Mental Health.

  14. The 3-D lattice theory of Flower Constellations

    NASA Astrophysics Data System (ADS)

    Davis, Jeremy J.; Avendaño, Martín E.; Mortari, Daniele

    2013-08-01

    Flower Constellations (FCs) have been extensively studied for use in optimal constellation design. The Harmonic FCs (HFCs) subset, representing the symmetric configurations, have recently been reformulated into 2-D Lattice Flower Constellations (2D-LFCs), encompassing the complete set of HFCs. Elliptic orbits are generally avoided due to the deleterious effects of Earth's oblateness on the constellation, but here we present a novel concept for avoiding this problem and enabling more effective global coverage utilizing elliptic orbits. This new 3D Lattice Flower Constellations (3D-LFCs) framework generalizes the 2D-LFCs, Walker constellations, elliptical Walker constellations, and many of Draim's global coverage constellations. Previous studies have shown FCs can provide improved performance in global navigation over existing Global Navigation Satellite Systems (GNSS). We found a 3D-LFC design that improved the average positioning accuracy by 3.5 % while reducing launch \\varDelta v requirements when compared to the existing Galileo GNSS constellation.

  15. APM for a Constellation Intersatellite Link - EM Qualification and Lessons Learned

    NASA Technical Reports Server (NTRS)

    Hartel, Frank; Kozilek, Horst

    2016-01-01

    For an Intersatellite Link (ISL) of a future constellation program, a study phase was initiated by ESA to design a mechanism for Radio Frequency communication. Airbus DS Friedrichshafen (ADSF) proposed a design based on the Antenna Pointing Mechanism (APM) family with modifications that met the stated needs of the constellation. A qualification program was started beginning in September 2015 to verify the launch and thermal loads and the equipment performance (Radio Frequency, Pointing, Microvibration and Magnetic Moment). Technical challenges identified with the Engineering Model will be discussed within this paper.

  16. Machines and cutters: Constellation®.

    PubMed

    Witmer, Matthew T; Dugel, Pravin U

    2014-01-01

    The Alcon Constellation® provides state-of-the-art technology for vitrectomy surgery. Its innovative features include utilization of high-speed and small-gauge vitrectomy systems, surgeon-controlled duty cycle, fine intraocular pressure control, and integrated laser and intraocular gas mixing capabilities. The goal of vitrectomy surgery is the safe and efficient removal of vitreous while avoiding iatrogenic retinal tears or iatrogenic incarceration of retinal tissue. This requires the removal of vitreous in a controlled manner while maintaining safe levels of intraocular pressure. The Alcon Constellation contains improvements in technology that allow a surgeon to consistently accomplish these goals.

  17. Optimizing Spacecraft Placement for Liaison Constellations

    NASA Technical Reports Server (NTRS)

    Chow, C. Channing; Villac, Benjamin F.; Lo, Martin W.

    2011-01-01

    A navigation and communications network is proposed to support an anticipated need for infrastructure in the Earth-Moon system. Periodic orbits will host the constellations while a novel, autonomous navigation strategy will guide the spacecraft along their path strictly based on satellite-to-satellite telemetry. In particular, this paper investigates the second stage of a larger constellation optimization scheme for multi-spacecraft systems. That is, following an initial orbit down-selection process, this analysis provides insights into the ancillary problem of spacecraft placement. Two case studies are presented that consider configurations of up to four spacecraft for a halo orbit and a cycler trajectory.

  18. Optimizing Spacecraft Placement for Liaison Constellations

    NASA Technical Reports Server (NTRS)

    Chow, C. Channing; Villac, Benjamin F.; Lo, Martin W.

    2011-01-01

    A navigation and communications network is proposed to support an anticipated need for infrastructure in the Earth-Moon system. Periodic orbits will host the constellations while a novel, autonomous navigation strategy will guide the spacecraft along their path strictly based on satellite-to-satellite telemetry. In particular, this paper investigates the second stage of a larger constellation optimization scheme for multi-spacecraft systems. That is, following an initial orbit down-selection process, this analysis provides insights into the ancillary problem of spacecraft placement. Two case studies are presented that consider configurations of up to four spacecraft for a halo orbit and a cycler trajectory.

  19. BRITE-Constellation: Science Operations Concept

    NASA Astrophysics Data System (ADS)

    Kuschnig, R.

    2008-01-01

    The BRITE-Constellation currently consists of two nano-satellites: BRITE-AUSTRIA and Uni-BRITE. Both are in principle of identical build with one exception, the respective telescopes will be designed for two different bandpasses one constrained to RED (555-690nm) and the other to BLUE (400-450nm) wavelengths. In general both satellites will collect data from the same stars during any particular observing run. A proposal to build and launch an additional pair of spacecrafts to complement the constellation is currently under review. This article describes the organization structure, the main operations tasks and the software tools to conduct the mission.

  20. Automating Operational and Science Analysis Processes with the Autonomous Sciencecraft Constellation

    NASA Technical Reports Server (NTRS)

    Davies, A. G.; Greeley, R.; Baker, V.; Williams, K. K.; Dohm, J.; Castano, R.; Mjolsness, E.; Roden, J.; Stough, T.; Chien, S.

    2002-01-01

    The Autonomous Sciencecraft Constellation-Techsat 21 mission is a NASA New Millennium Program mission selected for flight in 2004. ASC will autonomously perform science analyses of X-band radar data, while in Earth orbit. Additional information is contained in the original extended abstract.

  1. International Earth Science Constellation (ESC) Introduction

    NASA Technical Reports Server (NTRS)

    Guit, William J.; Machado, Michael J.

    2016-01-01

    This is the Welcome and Introduction presentation for the International Earth Science Constellation (ESC) Mission Operations Working Group (MOWG) meeting held in Albuquerque NM from September 27-29. It contains an org chart, charter, history, significant topics to be discussed, AquaAura 2017 inclination adjust maneuver calendar, a-train long range plans, upcoming events, and action items.

  2. Human Rating Requirements for NASA's Constellation Program

    NASA Technical Reports Server (NTRS)

    Berdich, Debbie

    2009-01-01

    This slide presentation reviews the human system integration (HSI) process in achieving human ratings for NASA Constellation Program (CxP). The NASA Procedural Requirements (NPR) document that defines the Human Ratings Requirements is NPR 8705.2B. An example of the human rating requirements flow down is given in the handling qualities for space craft control.

  3. Connect the Dots and Pinhole Constellations.

    ERIC Educational Resources Information Center

    Kominski, John

    1991-01-01

    Identifies a variety of methods to introduce constellations and asterisms to students in the classroom and planetarium prior to their study of the night sky. Materials used include transparencies, oatmeal boxes, photographic slides, and tracing paper. Exercises incorporate storytelling and prediction of location, movement, and seasonal patterns of…

  4. Optimizing space constellations for mobile satellite systems

    NASA Technical Reports Server (NTRS)

    Roussel, T.; Taisant, J.-P.

    1993-01-01

    Designing a mobile satellite system entails many complex trade-offs between a great number of parameters including: capacity, complexity of the payload, constellation geometry, number of satellites, quality of coverage, etc. This paper aims at defining a methodology which tries to split the variables to give rapidly some first results. The major input considered is the traffic assumption which would be offered by the system. A first key step is the choice of the best Rider or Walker constellation geometries - with different numbers of satellites - to insure a good quality of coverage over a selected service area. Another aspect to be addressed is the possible altitude location of the constellation, since it is limited by many constraints. The altitude ranges that seem appropriate considering the spatial environment, the launch and orbit keeping policy and the feasibility of the antenna allowing sufficient frequency reuse are briefly analyzed. To support these first considerations, some 'reference constellations' with similar coverage quality are chosen. The in-orbit capacity needed to support the assumed traffic is computed versus altitude. Finally, the exact number of satellite is determined. It comes as an optimum between a small number of satellites offering a high (and costly) power margin in bad propagation situation and a great number of less powerful satellites granting the same quality of service.

  5. Low Cost Constellations to Assist the Warfighter

    DTIC Science & Technology

    2006-08-01

    Low Cost Constellations to Assist the Warfighter Stuart Eves (SSTL), David Carter (EADS- Astrium ), David Beard (Dstl) Email: s.eves@sstl.co.uk Tel... Astrium Ltd Earth Observation & Science Anchorage Road Portsmouth, Hampshire PO3 5PU UK davidj.carter@astrium.eads.net David Beard DSTL

  6. Ancient homology of the mitochondrial contact site and cristae organizing system points to an endosymbiotic origin of mitochondrial cristae.

    PubMed

    Muñoz-Gómez, Sergio A; Slamovits, Claudio H; Dacks, Joel B; Baier, Kaitlyn A; Spencer, Katelyn D; Wideman, Jeremy G

    2015-06-01

    Mitochondria are eukaryotic organelles that originated from an endosymbiotic α-proteobacterium. As an adaptation to maximize ATP production through oxidative phosphorylation, mitochondria contain inner membrane invaginations called cristae. Recent work has characterized a multi-protein complex in yeast and animal mitochondria called MICOS (mitochondrial contact site and cristae organizing system), responsible for the determination and maintenance of cristae [1-4]. However, the origin and evolution of these characteristic mitochondrial features remain obscure. We therefore conducted a comprehensive search for MICOS components across the major groups that encompass eukaryotic diversity to determine the extent of conservation of this complex. We detected homologs for the majority of MICOS components among opisthokonts (the group containing animals and fungi), but only Mic60 and Mic10 were consistently identified outside this group. The conservation of Mic60 and Mic10 in eukaryotes is consistent with their central role in MICOS function [5-7], indicating that the basic mechanism for cristae determination arose early in evolution and has remained relatively unchanged. We found that eukaryotes with ultrastructurally simplified anaerobic mitochondria that lack cristae have also lost MICOS. We then searched for a prokaryotic MICOS and identified a homolog of Mic60 present only in α-proteobacteria, providing evidence for the endosymbiotic origin of mitochondrial cristae. Our study clarifies the origins of mitochondrial cristae and their subsequent evolutionary history, provides evidence for a general mechanism of cristae formation and maintenance in eukaryotes, and points to a new potential factor involved in membrane differentiation in prokaryotes.

  7. On the deployment and station keeping dynamics of N-body orbiting satellite constellations

    NASA Astrophysics Data System (ADS)

    Strong, Avaine

    This research explores the theory of relative motion to analyze formation flying, which is an orbital operations concept designed to maintain a predetermined trajectory of a spacecraft relative to a reference position or another reference spacecraft without making physical attachment (rendezvous). The trend to develop small, low-cost spacecraft has led many to recognize the advantage of flying multiple spacecraft in formation to achieve the correlated instrument measurements formerly possible only by flying many instruments on a single, large platform. This new requirement imposes additional complications on orbit maintenance, especially when each spacecraft has its own constraints. This research consists of two parts: (1) Constellation and Station Keeping in which the objective is to maintain the geometric configuration and to maintain approximately constant separation distances between spacecraft as they are moving in an elliptical orbit, about the Earth. (2) Deployment Stage in which spacecraft are deployed from an initial position (i.e. common location) to a final position of a predetermined geometric configuration, defined with respect to the original mother spacecraft. Constellation station keeping was investigated by implementing various propulsive maneuvers at different times based on Lagrange's planetary equations for impulsive (thrust) perturbations. Other constellation station keeping was based on the investigation of propulsive strategies that deliberately shifted the line of apsides by a predetermined (small) amount in order to maintain separation distances within certain bounds. And finally, a hybrid technique which consisted of a combination of shift in line of apsides and Linear Quadratic Regulator (LQR) feedback was investigated employing the Tschauner and Hempel equations of relative motion for elliptic orbits to minimize a secular relative drift cause by the gravitational perturbations(J2). Deployment of spacecraft is described by maneuvers from

  8. Measuring Earth's Radiation Imbalance using Cubesat Constellations

    NASA Astrophysics Data System (ADS)

    Collins, W. D.; Courtade, S.; Immel, T. J.; Feldman, D.; Lorentz, S. R.; Dyrud, L. P.

    2016-12-01

    At present, the global annual-mean Earth Radiation Imbalance (ERI) is estimated to be of order 1 W/m2, although the uncertainty in ERI is much larger than this estimate. The best current satellite-only observational determinations of ERI range from -2 to +7 W/m2 unless major adjustments are made using ocean observations. Since measurements of ERI accurate to better than 0.5 W/m2 are essential for understanding and predicting changes in our climate, new missions to determine ERI in conjunction with ongoing ocean observations are urgently needed. These missions should reliably determine Earth's radiation balance at the temporal and spatial scales sufficient for relating ERI to the physical processes responsible for variability. The compelling objective of measuring ERI can be met using a constellation of satellites making global, high-frequency radiation measurements of the solar energy reflected and infrared energy radiated back to space with sufficient accuracy to determine the ERI to within 0.5 W/m2. In this presentation, we discuss the reasons and prospects for deploying a Cubesat constellation to realize this objective, simulations of the data that could be produced by this constellation, and the advantages of the spatial coverage and high temporal frequency afforded by the constellation. These advantages apply both to estimating long-term ERI and to quantifying the radiation budgets of individual synoptic-scale weather systems. The innovations in this system involve both the use of Cubesats and of compact, continuously calibrated wide-field-of-view radiometers. We demonstrate the feasibility of such a constellation using the ongoing proof-of-concept deployment of the target radiometers onboard the upcoming NASA RAVAN (Radiometer Assessment using Vertically Aligned Nanotubes) mission.

  9. Aquarius-Pisces Constellation Boundary Update

    NASA Astrophysics Data System (ADS)

    Durst, Steve

    2017-06-01

    Observation, mapping and study of Galaxy Stars has provided humanity direction, foundation, clarity and understanding through the ages.Human civilization advances itself using increasing intelligence and knowledge to develop tools and know how, the science of constellation star maps included: All that has been created by humanity, is to serve humanity.When people continue to use constellation star maps that no longer serve people effectively, the maps are updated, as is now the Aquarius-Pisces Constellation Boundary Update (APCBU), which marks 2000 as the year the Sun is in Aquarius at the vernal equinox.The 21st Century APCBU accounts for and incorporates science factors of precession, relativity and galacticity for professional astronomers, and social imperatives of increasing freedom, liberation and egalitarian culture for the 7.5 billion people of Earth.Twenty years into this first century of a new millennium and a new age is an effective time for an APCBU of such elegant simplicity that it changes less than 0.1% of the area of the IAU 1930 official constellation map, which marks 2597 about the year the Sun is in Aquarius at the time of the vernal equinox.The 21st Century APCBU results provide clarity and direction for humanity's next 2,000 years, if not 10,000 or 12,000 years, and advance the official astronomy / science start of the Aquarius Age -- long anticipated, desired, and imperative, especially in America -- by some 600 years.How much attention is increasingly focused on this region of the sky -- such as the recent discovery of 7 Earth-like worlds orbiting the Trappist-1 star in the Aquarius constellation -- will be an epochal 21st Century phenomenon of human science, society, and starlife.

  10. Life Support Technology Challenges for NASA's Constellation Program

    NASA Technical Reports Server (NTRS)

    Carrasquillo, Robyn; Bagdigian, Robert; Ewert, Michael

    2007-01-01

    The presentation is for the ECLSS session of the Constellation Technology Exchange Conference and is to describe what new technology challenges the Constellation mission presents for the ECLSS, in order to communicate these needs with industry.

  11. Navigation Constellation Design Using a Multi-Objective Genetic Algorithm

    DTIC Science & Technology

    2015-03-26

    NAVIGATION CONSTELLATION DESIGN USING A MULTI-OBJECTIVE GENETIC ALGORITHM THESIS MARCH 2015...the United States. AFIT-ENY-MS-15-M-245 NAVIGATION CONSTELLATION DESIGN USING A MULTI-OBJECTIVE GENETIC ALGORITHM THESIS Presented to...DISTRIBUTION UNLIMITED. AFIT-ENY-MS-15-M-245 NAVIGATION CONSTELLATION DESIGN USING A MULTI-OBJECTIVE GENETIC ALGORITHM Heather C. Diniz

  12. Origines de la nomenclature astrale

    NASA Astrophysics Data System (ADS)

    Duchesne-Guillemin, J.

    Within a survey of the Indo-European, Sumero-Babylonian, Greek, Arabic, and modern origins of the names of the constellations, stars, planets, satellites, asteroids, etc., an explanation is offered of the Omega sign used in Greek horoscopes for the lunar nodes but already appearing on Babylonian reliefs. Its origin is traced back to the Sumerian constellations of the Yoke, later called the Dragon.

  13. Radio occultation constellation deployment via impulses along the geomagnetic field

    NASA Astrophysics Data System (ADS)

    Ovchinnikov, Michael Yu.; Trofimov, Sergey P.; Chang, Hao-Chi

    2013-01-01

    The problem of radio occultation (RO) constellation deployment is examined. Of particular interest here is to study the feasibility of using passively stabilized small satellites. We consider a pair of satellites supplied with a passive magnetic attitude control system. The capsule containing two satellites is launched into a parking orbit and stabilized along the geomagnetic field direction. Then the satellites are pushed apart by a separation spring at some point of orbit. If necessary for braking, one or two thrusters may be placed along the stabilized axis of each satellite. Optimization of the separation point and velocity along with the ΔV required for possible braking thrust is carried out in accordance with some specific demands of RO missions. Atmospheric drag and Earth oblateness are taken into account as perturbations. It is shown that, depending on a mission scenario, the separation with either one braking thrust or no thrusts at all is preferable.

  14. Investigating GAIM-GM's Capability to Sense Ionospheric Irregularities via Walker Satellite Constellations

    NASA Astrophysics Data System (ADS)

    McClung, B.

    2015-12-01

    GAIM-GM is a modularized physics based data assimilation model, that ingests data from multiple data sources. One data source is slant total electron content (TEC) from a ground station network to satellites, and along the occultation path between multiple satellites. This study examines GAIM-GM's capability to sense a scintillation feature in the ionosphere, overlaid on an IFM electron density grid, from simulated satellite constellations ingesting the slant TEC values into GAIM-GM. Satellite constellations were developed in an extension of Matlab, called STK. A real ground station network generated from IGS was ingested into STK to calculate access times to the satellite constellation and use the access data to compute the slant TEC values on the perturbed IFM grid. It was discovered that a Walker constellation would give the most frequent revisit time to the scintillation feature, which co-rotates with the Earth, capturing both the day and nightside ionosphere throughout the evaluation period (96 hrs). The size of the feature was varied along with the number of satellites in the Walker constellation. 25 different scenarios with these parameters varied were created to determine the sensitivity of GAIM-GM to sense the feature. A simple heuristic algorithm was applied comparing the truth data, in this case the perturbed IFM grid, to the GAIM-GM output in each scenario across the entire grid, and for those grid points within the feature.

  15. Doppler characterization of laser inter-satellite links for optical LEO satellite constellations

    NASA Astrophysics Data System (ADS)

    Yang, Qinglong; Tan, Liying; Ma, Jing

    2009-09-01

    Because of ensuring very low propagation delay between satellites, and providing global space-based broadband network services, low earth orbit (LEO) satellite constellations with laser inter-satellite links (ISLs) are considered to be the enabling technology to satisfy the increasing data traffic demand. However, significant Doppler can be observed by the onboard terminals on the ISLs, due to the high relative speed of the two communicating LEO satellites. This paper describes an analytic derivation of the Doppler wavelength shift measured by the terminal onboard a satellite on the signal transmitted through the ISLs. The Point-Ahead Mechanism of the optical ISLs is considered in the analytical expression of the Doppler wavelength shift. Then, in terms of the ISLs characteristics of the satellite constellations, the expression of Doppler wavelength shift is deduced into two aspects. First, for the full time accessing ISLs, it evolves as a function of the constellation parameters. Thus, the Doppler characterization for two kinds of interorbit full time accessing ISLs of LEO satellite constellations is analyzed. Second, for the intermittent accessing ISLs, the expression of Doppler wavelength shift is given as a function of the minimum ISL distance between two communicating satellites. And the visibility duration of the destination satellite at the source satellite is estimated for the intermittent ISLs. This work is helpful to evaluate the design of constellation networking.

  16. a Novel Proposal of GAOFEN-3 Satellite Constellation for Multi-Applications

    NASA Astrophysics Data System (ADS)

    Qiu, X.; Ding, C.; Lei, B.; Han, B.; Li, F.

    2017-09-01

    Gaofen-3 is the first C-band fully polarimetric SAR satellite in China, which is widely used in various fields such as ocean monitoring, disaster reduction and so on. In this paper, a new satellite constellation is proposed based on the orbit of Gaofen-3 satellite. The constellation includes Gaofen-3 and other two duplicates. It is able to do repeat-pass interferometry, repeat-pass differential interferometry, along-track interferometry and stereo measurement. With these abilities, it can generate the earth DEM without ground control points and have better performance in moving target identification and monitoring. The performance and the system requirements are analysed, which provides a good reference for the design of spaceborne SAR constellation.

  17. Spatial Sense and Perspective: A 3-D Model of the Orion Constellation

    NASA Astrophysics Data System (ADS)

    Heyer, I.; Slater, T. F.; Slater, S. J.

    2012-08-01

    Building a scale model of the Orion constellation provides spatial perspective for students studying astronomy. For this activity, students read a passage from literature that refers to stars being strange when seen from a different point of view. From a data set of the seven major stars of Orion they construct a 3-D distance scale model. This involves the subject areas of astronomy, mathematics, literature and art, as well as the skill areas of perspective, relative distances, line-of-sight, and basic algebra. This model will appear from one side exactly the way we see it from Earth. But when looking at it from any other angle the familiar constellation will look very alien. Students are encouraged to come up with their own names and stories to go with these new constellations. This activity has been used for K-12 teacher professional development classes, and would be most suitable for grades 6-12.

  18. Global Coverage from Ad-Hoc Constellations in Rideshare Orbits

    NASA Technical Reports Server (NTRS)

    Ellis, Armin; Mercury, Michael; Brown, Shannon

    2012-01-01

    A promising area of small satellite development is in providing higher temporal resolution than larger satellites. Traditional constellations have required specific orbits and dedicated launch vehicles. In this paper we discuss an alternative architecture in which the individual elements of the constellation are launched as rideshare opportunities. We compare the coverage of such an ad-hoc constellation with more traditional constellations. Coverage analysis is based on actual historical data from rideshare opportunities. Our analysis includes ground coverage and temporal revisits for Polar, Tropics, Temperate, and Global regions, comparing ad-hoc and Walker constellation.

  19. Global Coverage from Ad-Hoc Constellations in Rideshare Orbits

    NASA Technical Reports Server (NTRS)

    Ellis, Armin; Mercury, Michael; Brown, Shannon

    2012-01-01

    A promising area of small satellite development is in providing higher temporal resolution than larger satellites. Traditional constellations have required specific orbits and dedicated launch vehicles. In this paper we discuss an alternative architecture in which the individual elements of the constellation are launched as rideshare opportunities. We compare the coverage of such an ad-hoc constellation with more traditional constellations. Coverage analysis is based on actual historical data from rideshare opportunities. Our analysis includes ground coverage and temporal revisits for Polar, Tropics, Temperate, and Global regions, comparing ad-hoc and Walker constellation.

  20. Constellation based DORIS receiver network for ionospheric data

    NASA Astrophysics Data System (ADS)

    Rainwater, D.; Gaussiran, T.; Barnum, B.

    2011-12-01

    Study of the upper and lower atmosphere has advanced to the point where a compelling need has emerged for global real-time specification of the most important observations as inputs to climate models. For the ionosphere, plasmasphere and magnetosphere this is the local free electron density (ED); for the troposphere it is the local water vapor content (WVC). We describe a proposal made to the GEOScan geoscience collaboration for a DORIS receiver to be flown on the Iridium-NEXT constellation that would provide precise, real-time measurements of both bulk ED WVC, as well as ionospheric scintillation; and precise orbit determination to the 1-3 cm level, thus valuable to the Earth gravity science community. Iridium-NEXT is a constellation of 66 satellites in six polar orbit planes, to be deployed starting in 2015. We describe how the DORIS frequency lever arm is superior to that of GPS for ionospheric purposes, and how DORIS data is currently being used to generate TWV data sets of comparable precision to GPS and VLBI data. GEOScan data would be persistent, global and real-time. Its data would be made available publicly in near-real-time.

  1. The Magnetospheric Constellation Mission (MC-DRACO)

    NASA Technical Reports Server (NTRS)

    Moore, Thomas E.

    2003-01-01

    The Magnetospheric Constellation Mission Dynamic Response and Coupling Observatory (MC-DRACO), the logical outgrowth of a sequence of STP missions, will explore plasma transport and energy conversion processes over a broad range of spatial sizes. Designed to be a meso-/macroscope for the magnetotail, it will resolve persistent controversies and yield a new understanding on which to build a predictive science of next generation magnetospheric meteorology.

  2. The Magnetospheric Constellation Mission (MC-DRACO)

    NASA Technical Reports Server (NTRS)

    Moore, Thomas E.

    2003-01-01

    The Magnetospheric Constellation Mission Dynamic Response and Coupling Observatory (MC-DRACO), the logical outgrowth of a sequence of STP missions, will explore plasma transport and energy conversion processes over a broad range of spatial sizes. Designed to be a meso-/macroscope for the magnetotail, it will resolve persistent controversies and yield a new understanding on which to build a predictive science of next generation magnetospheric meteorology.

  3. Fouled Anchors: The CONSTELLATION Question Answered

    DTIC Science & Technology

    1991-09-01

    designs ............................... 175 21. Shaded image of 1795 design ................... .................... 176 22. Shaded image of 1853...some time before he would detect the underlying trouble. NAVY ASSISTANCE The Constellation ha : a good ally in the Navy and in Admiral Eller who...trance, Leek " detected " three ghosts: Commodore Truxtun, Seaman Neal Harvey who had been executed on board in 1799 during battle with L’Jnsurgente

  4. The GeoEye Satellite Constellation

    NASA Technical Reports Server (NTRS)

    Dial, Gene; Cole, Aaron; Lutes, James; McKune, John; Martinez, Mike; Rao, R. S.; Taylor, Martin

    2007-01-01

    The GeoEye Constellation consists of: a) IKONOS and OrbView-3 for high resolution; b) GeoEye with higher resolution 1Q2007; c) RESOUCESAT-1 for global crop assessment; d) OrbView-2 for ocean research and fish. IKONOS performance in 2005 included stable image quality, radiometry and geometric accuracy. reliability is 80% to 2008. Demonstrated capacity for high-volume, quick-response collection and production.

  5. Autonomy Architectures for a Constellation of Spacecraft

    NASA Technical Reports Server (NTRS)

    Barrett, Anthony

    2000-01-01

    This paper describes three autonomy architectures for a system that continuously plans to control a fleet of spacecraft using collective mission goals instead of goals of command sequences for each spacecraft. A fleet of self-commanding spacecraft would autonomously coordinate itself to satisfy high level science and engineering goals in a changing partially-understood environment-making feasible the operation of tens of even a hundred spacecraft (such as for interferometer or magnetospheric constellation missions).

  6. Constellation X-Ray Mission and Support

    NASA Technical Reports Server (NTRS)

    Grady, Jean (Technical Monitor); Tananbaum, H.

    2002-01-01

    This Fourth Annual Report summarizes work performed by the Smithsonian Astrophysical Observatory (SAO) for NASA Goddard Space Flight Center (GSFC) under Cooperative Agreement NCC5-368. The Agreement is entitled Constellation X-ray Mission Study and SAO continues to perform work under the overall direction of Dr. Harvey Tananbaum, the SAO Principal Investigator for the program. Mr. Robert Rasche is the SAO Program Manager and is responsible for day-to-day program management at SAO and coordination with GSFC. The report summarizes the main areas of SAO activity. Most of the work has been done jointly with personnel from GSFC and Marshall Space Flight Center (MSFC). We describe SAO participation in these efforts. As is appropriate to a Cooperative Agreement, SAO continued to work with GSFC in an integrated team mode. SAO was involved in the overall mission management, technology development, scientific direction, and mission definition. While formal overall management responsibility resides with GSFC, scientific lead and subordinate responsibilities continue to be shared by GSFC and SAO. The work performed by SAO is consistent with the SAO proposal 'Constellation X-ray Mission Study and Optics Development' dated September 1997, which was the basis for establishing the Cooperative Agreement under which SAO is currently funded. Over time, the scope of the effort has expanded somewhat to accommodate the needs of the project. Work, except for meeting support and high priority program tasks, has been at a level of effort. Priorities and work progress have been closely coordinated with the Constellation-X Project Formulation Manager at GSFC. Funding limitations constrained the work accomplished during this period. Nonetheless, a significant amount of work was accomplished. Under the Agreement, SAO performed work in seven major areas of activity. These areas related to: Constellation X-ray Mission Facility Definition Team and Study Management; Science Support; Spectroscopy X

  7. GPS radio occultation constellation design with the optimal performance in Asia Pacific region

    NASA Astrophysics Data System (ADS)

    Asgarimehr, Milad; Hossainali, Masoud Mashhadi

    2015-06-01

    The growing desire for better spatial and also temporal distribution of radio occultation data is a motivation for extensive researches considering either number of GNSS/receiver satellites or better optimization tools resulting in better distributions. This paper addresses the problem of designing a global positioning system-only radio occultation mission with the optimal performance in Asia Pacific region. Constellation Patterns are discussed and 2D-lattice and 3D-lattice flower constellations are adopted to develop a system with circular and elliptical orbits, respectively. A perturbed orbit propagation model leading to significantly more accurate pre-analysis is used. Emphasizing on the spatial and also temporal distribution of radio occultation events for the first time, distribution norm is provided as a volumetric distribution measure using Voronoi diagram concept in a 3D space consisting temporal and spatial intervals. Optimizations are performed using genetic algorithm to determine optimal constellation design parameters by the suitable fitness function and constraints devised. The resulted constellation has been evaluated by a regional comparison to the globally distributed FORMOSAT-3/COSMIC in terms of the distribution norm, number of radio occultation events and also coverage as an additional point-to-point distribution measure. Although it is demonstrated that the optimal 3D-lattice enjoys better performance than FORMOSAT-3, the design approach results in a 2D-lattice flower constellation which is superior to other constellations in regional emphasis of radio occultation events. Its global performance is discussed and it is demonstrated that using multi-GNSS receiver to increase satellites may not guarantee a good distribution of radio occultation data in some aspects.

  8. 41 CFR 302-7.6 - What are the authorized origin and destination points for the transportation of HHG and PBP&E?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... origin and destination points for the transportation of HHG and PBP&E? 302-7.6 Section 302-7.6 Public... STORAGE OF PROPERTY 7-TRANSPORTATION AND TEMPORARY STORAGE OF HOUSEHOLD GOODS AND PROFESSIONAL BOOKS, PAPERS, AND EQUIPMENT (PBP&E) General Rules § 302-7.6 What are the authorized origin and...

  9. 41 CFR 302-7.6 - What are the authorized origin and destination points for the transportation of HHG and PBP&E?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... origin and destination points for the transportation of HHG and PBP&E? 302-7.6 Section 302-7.6 Public... STORAGE OF PROPERTY 7-TRANSPORTATION AND TEMPORARY STORAGE OF HOUSEHOLD GOODS AND PROFESSIONAL BOOKS, PAPERS, AND EQUIPMENT (PBP&E) General Rules § 302-7.6 What are the authorized origin and...

  10. 41 CFR 302-7.6 - What are the authorized origin and destination points for the transportation of HHG and PBP&E?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... origin and destination points for the transportation of HHG and PBP&E? 302-7.6 Section 302-7.6 Public... STORAGE OF PROPERTY 7-TRANSPORTATION AND TEMPORARY STORAGE OF HOUSEHOLD GOODS AND PROFESSIONAL BOOKS, PAPERS, AND EQUIPMENT (PBP&E) General Rules § 302-7.6 What are the authorized origin and...

  11. 41 CFR 302-7.6 - What are the authorized origin and destination points for the transportation of HHG and PBP&E?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... origin and destination points for the transportation of HHG and PBP&E? 302-7.6 Section 302-7.6 Public... STORAGE OF PROPERTY 7-TRANSPORTATION AND TEMPORARY STORAGE OF HOUSEHOLD GOODS AND PROFESSIONAL BOOKS, PAPERS, AND EQUIPMENT (PBP&E) General Rules § 302-7.6 What are the authorized origin and...

  12. 41 CFR 302-9.207 - What will I be reimbursed if I transport my POV from a point of origin or to a destination that...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 4 2012-07-01 2012-07-01 false What will I be reimbursed if I transport my POV from a point of origin or to a destination that is different from my authorized origin or destination? 302-9.207 Section 302-9.207 Public Contracts and Property...

  13. Constellation X-Ray Mission and Support

    NASA Astrophysics Data System (ADS)

    Tananbaum, H.

    2002-01-01

    This report is a supplement to the Third Annual Report summarizing work performed by the Smithsonian Astrophysical Observatory (SAO) for NASA Goddard Space Flight Center (GSFC) under Cooperative Agreement NCC5-3681. The Agreement is entitled 'Constellation X-ray Mission Study and Support.' This supplementary report covers the period from October 1, 2001 through January 10, 2002. The report has been prepared and submitted to ensure that the Constellation-X Project Office at GSFC has current performance information needed to evaluate a proposed modified budget for FY02. That proposed budget is being submitted separately. SAO continues to perform work under the overall direction of Dr. Harvey Tananbaum, the SAO Principal Investigator for the program. Mr. Robert Rasche is the SAO Program Manager and is responsible for day-to-day program management at SAO and coordination with GSFC. The report summarizes the main areas of SAO activity. Most of the work has been done jointly with personnel from GSFC and Marshall Space Flight Center (MSFC). We describe SAO participation in these efforts. Under the Agreement, SAO performed work in seven major areas of activity. These areas related to: (1) Constellation X-ray Mission Facility Definition Team and Study Management; (2) Science Support; (3) Spectroscopy X-ray Telescope (SXT); (4) Systems Engineering; (5) Travel in Support of the Work Effort; and (6) In-house Management and Coordination.

  14. Optimization of satellite constellation reconfiguration maneuvers

    NASA Astrophysics Data System (ADS)

    Appel, Leonid; Guelman, Moshe; Mishne, David

    2014-06-01

    Constellation satellites are required to perform orbital transfer maneuvers. Orbital transfer maneuvers, as opposed to orbital correction maneuvers, are seldom performed but require a substantial amount of propellant for each maneuver. The maneuvers are performed in order to obtain the desired constellation configuration that satisfies the coverage requirements. In most cases, the single-satellite position is immaterial; rather the relative position between constellation multiple-satellites is to be controlled. This work deals with the solution to the coupled optimization problem of multiple-satellite orbital transfer. The studied problem involves a coupled formulation of the terminal conditions of the satellites. The solution was achieved using functional optimization techniques by a combined algorithm. The combined algorithm is based on the First Order Gradient and Neighboring-Extremals Algorithms. An orbital transfer optimization tool was developed. This software has the ability to consider multiple satellites with coupled terminal conditions. A solution to the multiple-satellite orbital transfer optimization problem is presented. A comparison of this solution to the uncoupled case is presented in order to review the benefits of using this approach. It is concluded that the coupled transfer maneuver solution approach is more computationally efficient and more accurate. Numerical solutions for a number of representative cases are presented.

  15. Constellation X-Ray Mission and Support

    NASA Technical Reports Server (NTRS)

    Tananbaum, H.; Grady, Jean (Technical Monitor)

    2002-01-01

    This report is a supplement to the Third Annual Report summarizing work performed by the Smithsonian Astrophysical Observatory (SAO) for NASA Goddard Space Flight Center (GSFC) under Cooperative Agreement NCC5-3681. The Agreement is entitled 'Constellation X-ray Mission Study and Support.' This supplementary report covers the period from October 1, 2001 through January 10, 2002. The report has been prepared and submitted to ensure that the Constellation-X Project Office at GSFC has current performance information needed to evaluate a proposed modified budget for FY02. That proposed budget is being submitted separately. SAO continues to perform work under the overall direction of Dr. Harvey Tananbaum, the SAO Principal Investigator for the program. Mr. Robert Rasche is the SAO Program Manager and is responsible for day-to-day program management at SAO and coordination with GSFC. The report summarizes the main areas of SAO activity. Most of the work has been done jointly with personnel from GSFC and Marshall Space Flight Center (MSFC). We describe SAO participation in these efforts. Under the Agreement, SAO performed work in seven major areas of activity. These areas related to: (1) Constellation X-ray Mission Facility Definition Team and Study Management; (2) Science Support; (3) Spectroscopy X-ray Telescope (SXT); (4) Systems Engineering; (5) Travel in Support of the Work Effort; and (6) In-house Management and Coordination.

  16. Debris environment interactions with low Earth orbit constellations

    NASA Technical Reports Server (NTRS)

    Reynolds, Robert; Bade, Anette; Siebold, Karl; Johnson, Nicholas

    1997-01-01

    Several low earth orbit communication satellite constellations are planned. Due to their size and complexity, these constellations potentially contribute to the orbital debris environment. The results of a parametric assessment of the impact of low earth orbit constellations on the orbital debris environment are presented. The increase in loss rate of non constellation spacecraft is considered, as well as the increase in the loss rate or replacement rate of constellation satellites as a result of debris impact. Primary parameters in the analysis are the number, size and altitude of the constellation. Parameters are defined for the vulnerable area of loss of spacecraft and the disposition of constellation spacecraft at the end of its life.

  17. End-of-Mission Planning Challenges for a Satellite in a Constellation

    NASA Technical Reports Server (NTRS)

    Boain, Ronald J.

    2013-01-01

    At the end of a mission, satellites embedded in a constellation must first perform propulsive maneuvers to safely exit the constellation before they can begin with the usual end-of-mission activities: deorbit, passivation, and decommissioning. The target orbit for these exit maneuvers must be sufficiently below the remaining constellation satellites such that, once achieved, there is no longer risk of close conjunctions. Yet, the exit maneuvers must be done based on the spacecraft's state of health and operational capability when the decision to end the mission is made. This paper focuses on the recently developed exit strategy for the CloudSat mission to highlight problems and issues, which forced the discarding of CloudSat's original EoM Plan and its replacement with a new plan consistent with changes to the spacecraft's original operational mode. The analyses behind and decisions made in formulating this new exit strategy will be of interest to other missions in a constellation currently preparing to update their End-of-Mission Plan.

  18. End-of-Mission Planning Challenges for a Satellite in a Constellation

    NASA Technical Reports Server (NTRS)

    Boain, Ronald J.

    2013-01-01

    At the end of a mission, satellites embedded in a constellation must first perform propulsive maneuvers to safely exit the constellation before they can begin with the usual end-of-mission activities: deorbit, passivation, and decommissioning. The target orbit for these exit maneuvers must be sufficiently below the remaining constellation satellites such that, once achieved, there is no longer risk of close conjunctions. Yet, the exit maneuvers must be done based on the spacecraft's state of health and operational capability when the decision to end the mission is made. This paper focuses on the recently developed exit strategy for the CloudSat mission to highlight problems and issues, which forced the discarding of CloudSat's original EoM Plan and its replacement with a new plan consistent with changes to the spacecraft's original operational mode. The analyses behind and decisions made in formulating this new exit strategy will be of interest to other missions in a constellation currently preparing to update their End-of-Mission Plan.

  19. Automating Trend Analysis for Spacecraft Constellations

    NASA Technical Reports Server (NTRS)

    Davis, George; Cooter, Miranda; Updike, Clark; Carey, Everett; Mackey, Jennifer; Rykowski, Timothy; Powers, Edward I. (Technical Monitor)

    2001-01-01

    Spacecraft trend analysis is a vital mission operations function performed by satellite controllers and engineers, who perform detailed analyses of engineering telemetry data to diagnose subsystem faults and to detect trends that may potentially lead to degraded subsystem performance or failure in the future. It is this latter function that is of greatest importance, for careful trending can often predict or detect events that may lead to a spacecraft's entry into safe-hold. Early prediction and detection of such events could result in the avoidance of, or rapid return to service from, spacecraft safing, which not only results in reduced recovery costs but also in a higher overall level of service for the satellite system. Contemporary spacecraft trending activities are manually intensive and are primarily performed diagnostically after a fault occurs, rather than proactively to predict its occurrence. They also tend to rely on information systems and software that are oudated when compared to current technologies. When coupled with the fact that flight operations teams often have limited resources, proactive trending opportunities are limited, and detailed trend analysis is often reserved for critical responses to safe holds or other on-orbit events such as maneuvers. While the contemporary trend analysis approach has sufficed for current single-spacecraft operations, it will be unfeasible for NASA's planned and proposed space science constellations. Missions such as the Dynamics, Reconnection and Configuration Observatory (DRACO), for example, are planning to launch as many as 100 'nanospacecraft' to form a homogenous constellation. A simple extrapolation of resources and manpower based on single-spacecraft operations suggests that trending for such a large spacecraft fleet will be unmanageable, unwieldy, and cost-prohibitive. It is therefore imperative that an approach to automating the spacecraft trend analysis function be studied, developed, and applied to

  20. The Portraits of Ancient Constellations: A Seven Was Their Number

    NASA Astrophysics Data System (ADS)

    Gurshtein, A. A.

    1997-12-01

    In seeking for genesis of archaic astronomical knowledge, I have found evidence that the "figure-of-seven" and the "figure-of-twelve" became sacred as the indirect result of celestial observational practices during very different historical epoches. While the figure-of-twelve became sacred after the time of the Egyptian heretic pharaoh Akhenaten and Moses (and concurrently with the oldest parts of the Holy Bible), the figure-of-seven originated as far back in prehistory as (at least) 30-20 thousand years B.C.E. -- the time of the recognition of a lunar month. I propose that the first constellations were credited as attributive groups of seven stellar objects. The hypothesis is based, in particular, upon evidence produced through interpretation of sky maps.

  1. A Genuine Jahn-Teller System with Compressed Geometry and Quantum Effects Originating from Zero-Point Motion.

    PubMed

    Aramburu, José Antonio; García-Fernández, Pablo; García-Lastra, Juan María; Moreno, Miguel

    2016-07-18

    First-principle calculations together with analysis of the experimental data found for 3d(9) and 3d(7) ions in cubic oxides proved that the center found in irradiated CaO:Ni(2+) corresponds to Ni(+) under a static Jahn-Teller effect displaying a compressed equilibrium geometry. It was also shown that the anomalous positive g∥ shift (g∥ -g0 =0.065) measured at T=20 K obeys the superposition of the |3 z(2) -r(2) ⟩ and |x(2) -y(2) ⟩ states driven by quantum effects associated with the zero-point motion, a mechanism first put forward by O'Brien for static Jahn-Teller systems and later extended by Ham to the dynamic Jahn-Teller case. To our knowledge, this is the first genuine Jahn-Teller system (i.e. in which exact degeneracy exists at the high-symmetry configuration) exhibiting a compressed equilibrium geometry for which large quantum effects allow experimental observation of the effect predicted by O'Brien. Analysis of the calculated energy barriers for different Jahn-Teller systems allowed us to explain the origin of the compressed geometry observed for CaO:Ni(+) . © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Lagrange L4/L5 points and the origin of our Moon and Saturn's moons and rings.

    PubMed

    Gott, J Richard

    2005-12-01

    The current standard theory of the origin of the Moon is that the Earth was hit by a giant impactor the size of Mars causing ejection of debris from its mantle that coalesced to form the moon; but where did this Mars-sized impactor come from? Isotopic evidence suggests that it came from 1 AU radius in the solar nebula, and computer simulations are consistent with its approaching Earth on a zero-energy parabolic trajectory. How could such a large object form at 1 AU in a quiescent disk of planetesimals without having already collided with the Earth at an earlier epoch before having the chance to grow large? Belbruno and Gott propose that the giant impactor could have formed in a stable orbit from debris at the Earth's Lagrange point L(5) (or L(4)). It would grow quietly by accretion at L(5) (or L(4)), but eventually gravitational perturbations by other growing planetesimals would kick it out into a horseshoe orbit and finally into a chaotic creeping orbit, which Belbruno and Gott show would, with high probability, hit the Earth on a near zero-energy parabolic trajectory. We can see other examples of this phenomenon occurring in the solar system. Asteroid 2002AA29 is in a horseshoe orbit relative to the Earth that looks exactly like the horseshoe orbits that Belbruno and Gott found for objects that had been perturbed from L(4)/L(5). The regular moons of Saturn are made of ice and have the same albedo as the ring particles (ice chunks, plus some dust). We (J. R. Gott, R. Vanderbei, and E. Belbruno) propose that the regular icy moons of Saturn (out to the orbit of Titan), which are all in nearly circular orbits, formed out of a thin disk of planetesimals (ice chunks) rather like the rings of Saturn today only larger in extent. In such a situation formation of objects at L(4)/L(5) might be expected. Indeed, Saturn's moon Dione is accompanied by moons (Helene and Polydeuces) at both L(4) and L(5) Lagrange points, and Saturn's moon Tethys is also accompanied by moons

  3. GPM Constellation Reconfiguration and Mission Status

    NASA Technical Reports Server (NTRS)

    Hou, Arthur Y.

    2006-01-01

    The Global Precipitation Measurement (GPM) Mission is an international satellite mission that uses combined active and passive remote sensing techniques to improve global precipitation measurements derived from dedicated and operational passive microwave sensors. GPM is a science mission with integrated applications goals to (1) advance the knowledge of precipitation physics and the global water cycle variability, and (2) improve weather, climate, and hydrological prediction capabilities through more accurate and frequent measurements of global precipitation and innovative application methods. The GPM Mission is currently a partnership between NASA and the Japan Aerospace Exploration Agency (JAXA), with opportunities for additional domestic and international partners in satellite constellation buildup and ground validation activities. The GPM concept is centered on employing a dualfrequency precipitation radar and a microwave radiometer with high-frequency capabilities on a core satellite to serve as a physics observatory and calibration standard to provide a consistent framework for unifying precipitation measurements from a heterogeneous constellation of passive microwave sensors. Building on the siccess of TRMM, GPM extends combined radadradiometer precipitation measurements into the mid and high latitudes, with new science foci on improved capabilities for light-rain and snowfall measurements, as well as more accurate precipitation retrievals over land. With recent studies indicating that AMSU-B rainfall estimates are comparable in quality to those derived from conically-scanning radiometers over land, it is envisioned that cross-track microwave sounders with high-frequency channels on operational satellites such as the National Polar-orbiting Operational Environmental Satellite System (NPOESS), NPOESS Preparatory Project (NPP), NOAA-N', and MetOp satellites can play a significant role in augmenting conically-scanning microwave radiometers to achieve better

  4. Constellation X-Ray Observatory Unlocking the Mysteries of Black Holes, Dark Matter and Life Cycles of Matter in the Universe

    NASA Technical Reports Server (NTRS)

    Weaver, Kim; Wanjek, Christopher

    2004-01-01

    This document provides an overview of the Contellation X-Ray Observatory and its mission. The observatory consists of four x-ray telescopes borne on a satellite constellation at the Earth-Sun L2 point.

  5. Constellation X-Ray Observatory Unlocking the Mysteries of Black Holes, Dark Matter and Life Cycles of Matter in the Universe

    NASA Technical Reports Server (NTRS)

    Weaver, Kim; Wanjek, Christopher

    2004-01-01

    This document provides an overview of the Contellation X-Ray Observatory and its mission. The observatory consists of four x-ray telescopes borne on a satellite constellation at the Earth-Sun L2 point.

  6. Trade-space Analysis for Constellations

    NASA Astrophysics Data System (ADS)

    Le Moigne, J.; Dabney, P.; de Weck, O. L.; Foreman, V.; Grogan, P.; Holland, M. P.; Hughes, S. P.; Nag, S.

    2016-12-01

    Traditionally, space missions have relied on relatively large and monolithic satellites, but in the past few years, under a changing technological and economic environment, including instrument and spacecraft miniaturization, scalable launchers, secondary launches as well as hosted payloads, there is growing interest in implementing future NASA missions as Distributed Spacecraft Missions (DSM). The objective of our project is to provide a framework that facilitates DSM Pre-Phase A investigations and optimizes DSM designs with respect to a-priori Science goals. In this first version of our Trade-space Analysis Tool for Constellations (TAT-C), we are investigating questions such as: "How many spacecraft should be included in the constellation? Which design has the best cost/risk value?" The main goals of TAT-C are to: Handle multiple spacecraft sharing a mission objective, from SmallSats up through flagships, Explore the variables trade space for pre-defined science, cost and risk goals, and pre-defined metrics Optimize cost and performance across multiple instruments and platforms vs. one at a time. This paper describes the overall architecture of TAT-C including: a User Interface (UI) interacting with multiple users - scientists, missions designers or program managers; an Executive Driver gathering requirements from UI, then formulating Trade-space Search Requests for the Trade-space Search Iterator first with inputs from the Knowledge Base, then, in collaboration with the Orbit & Coverage, Reduction & Metrics, and Cost& Risk modules, generating multiple potential architectures and their associated characteristics. TAT-C leverages the use of the Goddard Mission Analysis Tool (GMAT) to compute coverage and ancillary data, streamlining the computations by modeling orbits in a way that balances accuracy and performance. TAT-C current version includes uniform Walker constellations as well as Ad-Hoc constellations, and its cost model represents an aggregate model

  7. Electrical Arc Ignition Testing for Constellation Program

    NASA Technical Reports Server (NTRS)

    Sparks, Kyle; Gallus, Timothy; Smith, Sarah

    2009-01-01

    NASA Johnson Space Center (JSC) Materials and Processes Branch requested that NASA JSC White Sands Test Facility (WSTF) perform testing for the Constellation Program to evaluate the hazard of electrical arc ignition of materials that could be in close proximity to batteries. Specifically, WSTF was requested to perform wire-break electrical arc tests to determine the current threshold for ignition of generic cotton woven fabric samples with a fixed voltage of 3.7 V, a common voltage for hand-held electrical devices. The wire-break test was developed during a previous test program to evaluate the hazard of electrical arc ignition inside the Extravehicular Mobility Unit [1].

  8. The Constellation-X Reflection Grating Spectrometer

    NASA Technical Reports Server (NTRS)

    Allen, Jean C.

    2006-01-01

    The Reflection Grating Spectrometer on the Constellation-X mission will provide high sensitivity, high-resolution spectra in the soft x-ray band. The RGS performance requirements are specified as a resolving power of greater than 300 and an effective area of greater than 1000 sq cm across most of the 0.25 to 2.0 keV band. These requirements are driven by the science goals of the mission. We will describe the performance requirements and goals, the reference design of the spectrometer, and examples of science cases where we expect data from the RGS to significantly advance our current understanding of the universe.

  9. Future Nanosatellite Constellation for Radio Occultation Measurements

    NASA Astrophysics Data System (ADS)

    Fallet, C.; Mahfouf, J. F.; Hauchechrne, A.; Mathieu, R.; Martin, T.; Capet, N.; Mandea, M.

    2016-08-01

    The future nanosatellite constellation for radio occultation measurements aims to provide 10000 occultations per day (horizon 2020). The radio occultation technique based on the refraction of an electromagnetic signal between a GNSS satellite (Global Navigation Satellite System) and a receiver satellite located o a low orbit provides a way to observe the Earth's atmosphere, especially its temperature, pressure and water vapor, but also the ionosphere. This technique is now considered a mature concept, the benefits clearly recognized by the communities of weather prediction, climatology and space weather. Activities are underway at CNES to define a low cost system and instrumental concept to satisfy the specifications of the different communities.

  10. The Constellation-X Reflection Grating Spectrometer

    NASA Technical Reports Server (NTRS)

    Allen, Jean C.

    2006-01-01

    The Reflection Grating Spectrometer on the Constellation-X mission will provide high sensitivity, high-resolution spectra in the soft x-ray band. The RGS performance requirements are specified as a resolving power of greater than 300 and an effective area of greater than 1000 sq cm across most of the 0.25 to 2.0 keV band. These requirements are driven by the science goals of the mission. We will describe the performance requirements and goals, the reference design of the spectrometer, and examples of science cases where we expect data from the RGS to significantly advance our current understanding of the universe.

  11. NASA Constellation Distributed Simulation Middleware Trade Study

    NASA Technical Reports Server (NTRS)

    Hasan, David; Bowman, James D.; Fisher, Nancy; Cutts, Dannie; Cures, Edwin Z.

    2008-01-01

    This paper presents the results of a trade study designed to assess three distributed simulation middleware technologies for support of the NASA Constellation Distributed Space Exploration Simulation (DSES) project and Test and Verification Distributed System Integration Laboratory (DSIL). The technologies are the High Level Architecture (HLA), the Test and Training Enabling Architecture (TENA), and an XML-based variant of Distributed Interactive Simulation (DIS-XML) coupled with the Extensible Messaging and Presence Protocol (XMPP). According to the criteria and weights determined in this study, HLA scores better than the other two for DSES as well as the DSIL.

  12. Adaptive Resource Management Technology for Satellite Constellations

    NASA Technical Reports Server (NTRS)

    Welch, Lonnie; Tjaden, Brett; Pfarr, Barbara B.; Hennessy, Joseph F. (Technical Monitor)

    2002-01-01

    This manuscript describes the Sensor Web Adaptive Resource Manager (SWARM) project. The primary focus of the project is on the design and prototyping of middleware for managing computing and network resources in a way that enables the information systems of satellite constellations to provide realtime performance within dynamic environments. The middleware has been prototyped, and it has been evaluated by employing it to manage a pool of distributed resources for the ITOS (Integrated Test and Operations System) satellite command and control software system. The design of the middleware is discussed and a summary of the evaluation effort is provided.

  13. Interactions of the space debris environment with mega constellations-Using the example of the OneWeb constellation

    NASA Astrophysics Data System (ADS)

    Radtke, Jonas; Kebschull, Christopher; Stoll, Enrico

    2017-02-01

    Recently, several announcements have been published to deploy satellite constellations into Low Earth Orbit (LEO) containing several hundred to thousands of rather small sized objects. The purpose of these constellations is to provide a worldwide internet coverage, even to the remotest areas. Examples of these mega-constellations are one from SpaceX, which is announced to comprise of about 4000 satellites, the Norwegian STEAM network, which is told to contain 4257 satellites, and the OneWeb constellation, which forms one of the smaller constellations with 720 satellites. As example constellation, OneWeb has been chosen. From all announced constellation, OneWeb by far delivered most information, both in regards to constellation design and their plans to encounter space debris issues, which is the reason why it has been chosen for these analyses. In this paper, at first an overview of the planned OneWeb constellation setup is given. From this description, a mission life-cycle is deduced, splitting the complete orbital lifetime of the satellites into four phases. Following, using ESA-MASTER, for each of the mission phases the flux on both single constellations satellites and the complete constellation are performed and the collision probabilities are derived. The focus in this analysis is set on catastrophic collisions. This analysis is then varied parametrically for different operational altitudes of the constellation as well as different lifetimes with different assumptions for the success of post mission disposal (PMD). Following the to-be-expected mean number of collision avoidance manoeuvres during all active mission phases is performed using ARES from ESA's DRAMA tool suite. The same variations as during the flux analysis are considered. Lastly the characteristics of hypothetical OneWeb satellite fragmentation clouds, calculated using the NASA Breakup model, are described and the impact of collision clouds from OneWeb satellites on the constellation itself is

  14. Constellation pharmacology: a new paradigm for drug discovery.

    PubMed

    Teichert, Russell W; Schmidt, Eric W; Olivera, Baldomero M

    2015-01-01

    Constellation pharmacology is a cell-based high-content phenotypic-screening platform that utilizes subtype-selective pharmacological agents to elucidate the cell-specific combinations (constellations) of key signaling proteins that define specific cell types. Heterogeneous populations of native cells, in which the different individual cell types have been identified and characterized, are the foundation for this screening platform. Constellation pharmacology is useful for screening small molecules or for deconvoluting complex mixtures of biologically active natural products. This platform has been used to purify natural products and discover their molecular mechanisms. In the ongoing development of constellation pharmacology, there is a positive feedback loop between the pharmacological characterization of cell types and screening for new drug candidates. As constellation pharmacology is used to discover compounds with novel targeting-selectivity profiles, those new compounds then further help to elucidate the constellations of specific cell types, thereby increasing the content of this high-content platform.

  15. The Constellations of the Zodiac: Astronomy for Low Vision and Blind People

    NASA Astrophysics Data System (ADS)

    Garcia, B.; Cicero, A.; Farrando, M.; Bruno, P.

    2006-08-01

    One thinks, in general, there exist areas of the knowledge to which it is not possible to be acceded if one of the senses is diminished. Nevertheless, the reality is far from this false concept: it is not necessary to hear to compose music, nor to see to come near to the starred sky. This book has the purpose to introduce to the readers with visual difficulties the amazing world of astronomy, by means of the transmission of basic concepts of positional astronomy (cardinal points, Earth movements, apparent movement of the celestial sphere), with special emphasis in: movement of precession, the concept of stellar magnitude, its representation in celestial charts, and relation to mythology. On the other hand, the figures associated with the 13 constellations in the region of the plane of the ecliptic are described. The texts and the images are displayed in two formats: for visually diminished people, one worked on the basis of the original engravings of the Uranographia by Hevelius (1690). These were adapted and simplified for their better understanding, and a recommended font size. For blind people, we use tactile feature for the figures and Braille for the text.

  16. The Origin of Sterol Biosynthesis: A Time-Point for the Evolution of Eukaryotes and the Presence of O2

    NASA Astrophysics Data System (ADS)

    Pearson, A.; Budin, M.; Brocks, J. J.

    2003-12-01

    The evolution of sterol biosynthesis is of critical interest to geoscientists as well as to evolutionary biologists. The first enzyme in the pathway, squalene monooxygenase (Sqmo), requires molecular oxygen (O2), suggesting that this process post-dates the evolution of Cyanobacteria. Additionally, the presence of steranes in ancient rocks marks the suggested time-point of eukaryogenesis(1). Sterol biosynthesis is viewed primarily as a eukaryotic process, and the frequency of its occurrence in bacteria long has been a subject of controversy. In this work, 19 protein gene sequences for Sqmo from eukaryotes were compared to all available complete and partial prokaryotic genomes. Twelve protein gene sequences representing oxidosqualene cyclase (Osc), the second enzyme of the sterol biosynthetic pathway, also were examined. The only unequivocal matches among the bacteria were the alpha-proteobacterium, Methylococcus capsulatus, in which sterol biosynthesis already is known, and the planctomycete, Gemmata obscuriglobus. The latter species contains the most abbreviated sterol pathway yet identified in any organism. Experiments show that the major sterols in Gemmata are lanosterol and its uncommon isomer, parkeol. In bacteria, the sterol biosynthesis genes occupy a contiguous coding region and may represent a single operon. Phylogenetic trees show that the sterol pathway in bacteria and eukaryotes has a common ancestry. Gemmata may retain the most ancient remnants of the pathway's origin, and it is likely that sterol biosynthesis in eukaryotes was acquired through gene transfer from bacteria. However, this work indicates that no known prokaryotes could produce the 24-ethyl steranes found in Archaean rocks(1). Therefore these compounds remain indicative of the presence of both eukaryotes and O2 at 2.7 Ga. 1. J. J. Brocks, G. A. Logan, R. Buick, R. E. Summons, (1999) Science 285, 1033-1036.

  17. Hyperspectral Cubesat Constellation for Natural Hazard Response

    NASA Technical Reports Server (NTRS)

    Mandl, Daniel; Crum, Gary; Ly, Vuong; Handy, Matthew; Huemmrich, Karl F.; Ong, Lawrence; Holt, Ben; Maharaja, Rishabh

    2016-01-01

    The authors on this paper are team members of the Earth Observing 1 (E0-1) mission which has flown an imaging spectrometer (hyperspectral) instrument called Hyperion for the past 15+ years. The satellite is able to image any spot on Earth in the nadir looking direction every 16 days and with slewing, of the satellite for up to a 23 degree view angle, any spot on the Earth can be imaged approximately every 2 to 3 days. EO-1 has been used to track many natural hazards such as wildfires, volcanoes and floods. An enhanced capability that has been sought is the ability to image natural hazards in a daily time series for space-based imaging spectrometers. The Hyperion cannot provide this capability on EO-1 with the present polar orbit. However, a constellation of cubesats, each with the same imaging spectrometer, positioned strategically can be used to provide daily coverage or even diurnal coverage, cost-effectively. This paper sought to design a cubesat constellation mission that would accomplish this goal and then to articulate the key tradeoffs.

  18. Constellation X-Ray Mission and Support

    NASA Technical Reports Server (NTRS)

    Grady, Jean (Technical Monitor); Tananbaum, H.

    2004-01-01

    This Fifth Annual Report summarizes work performed by the Smithsonian Astrophysical Observatory (SAO) for NASA Goddard Space Flight Center (GSFC) under Cooperative Agreement NCC5-368. The Agreement is entitled 'Constellation X-ray Mission Study and Support.' This report covers the period from October 1, 2002 through September 30,2003. The report summarizes the main areas of SAO activity. Most of the work has been done jointly with personnel from GSFC and Marshall Space Flight Center (MSFC). We describe SAO participation in these efforts. In spite of the work being mainly a level of effort, a significant amount of work was accomplished. Under the Agreement, SAO performed work in eight major areas of activity. These areas related to: 1) Constellation X-ray Mission Facility Definition Team and Study Management; 2) Science Support; 3) Spectroscopy X-ray Telescope (SXT); 4) Systems Engineering; 5) Travel in Support of the Work Effort; 6) In-house Management and Coordination; 7) Technical Readiness and Implementation Plan (TRIP) Report and Follow-up; 8) Industry Liaison and Study Preparation.

  19. Space Technology 5 - A Successful Micro-Satellite Constellation Mission

    NASA Technical Reports Server (NTRS)

    Carlisle, Candace; Webb, Evan H.

    2007-01-01

    The Space Technology 5 (ST5) constellation of three micro-satellites was launched March 22, 2006. During the three-month flight demonstration phase, the ST5 team validated key technologies that will make future low-cost micro-sat constellations possible, demonstrated operability concepts for future micro-sat science constellation missions, and demonstrated the utility of a micro-satellite constellation to perform research-quality science. The ST5 mission was successfully completed in June 2006, demonstrating high-quality science and technology validation results.

  20. 41 CFR 302-7.7 - May the origin and destination points be other than that prescribed in § 302-7.6?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 4 2012-07-01 2012-07-01 false May the origin and destination points be other than that prescribed in § 302-7.6? 302-7.7 Section 302-7.7 Public Contracts and... reimbursement is limited to the cost of transporting the property in one lot from the authorized origin to...

  1. Precise orbit determination of Multi-GNSS constellation including GPS GLONASS BDS and GALIEO

    NASA Astrophysics Data System (ADS)

    Dai, Xiaolei

    2014-05-01

    In addition to the existing American global positioning system (GPS) and the Russian global navigation satellite system (GLONASS), the new generation of GNSS is emerging and developing, such as the Chinese BeiDou satellite navigation system (BDS) and the European GALILEO system. Multi-constellation is expected to contribute to more accurate and reliable positioning and navigation service. However, the application of multi-constellation challenges the traditional precise orbit determination (POD) strategy that was designed usually for single constellation. In this contribution, we exploit a more rigorous multi-constellation POD strategy for the ongoing IGS multi-GNSS experiment (MGEX) where the common parameters are identical for each system, and the frequency- and system-specified parameters are employed to account for the inter-frequency and inter-system biases. Since the authorized BDS attitude model is not yet released, different BDS attitude model are implemented and their impact on orbit accuracy are studied. The proposed POD strategy was implemented in the PANDA (Position and Navigation Data Analyst) software and can process observations from GPS, GLONASS, BDS and GALILEO together. The strategy is evaluated with the multi-constellation observations from about 90 MGEX stations and BDS observations from the BeiDou experimental tracking network (BETN) of Wuhan University (WHU). Of all the MGEX stations, 28 stations record BDS observation, and about 80 stations record GALILEO observations. All these data were processed together in our software, resulting in the multi-constellation POD solutions. We assessed the orbit accuracy for GPS and GLONASS by comparing our solutions with the IGS final orbit, and for BDS and GALILEO by overlapping our daily orbit solution. The stability of inter-frequency bias of GLONASS and inter-system biases w.r.t. GPS for GLONASS, BDS and GALILEO were investigated. At last, we carried out precise point positioning (PPP) using the multi-constellation

  2. Design of observation / telecommunication constellations : Synergy through a simulation platform

    NASA Astrophysics Data System (ADS)

    Rainjonneau, S.; Gaertner, S.; Froment, F.; Raffier, B.

    2002-07-01

    Some new world-wide telecommunication or observation systems are based on LEO or MEO satellite constellations, used as relay between terminals or imaging target and gateways or ground stations, in order to provide telephony, high data rate or ground imaging to the end user. Such complex systems are characterized by several system constraints, due to the huge number of users or requests, and the movement of the satellites with regards to the Earth. The design of such whole system can be also considered as a complex problem. It has to be realized thanks to simulators, taking into account a part more or less important of the system constraints. This article presents a complete set of simulation tools, developed by Alcatel Space Industries, in the framework of different telecommunication and observation projects. These tools are regrouped inside a common workshop and based on a generic representation of new telecommunication and observation systems. Two major key points can be highlighted in this approach : two phases correspond to 0/A and A/B project phases and for each phase, five generic steps are followed to conduct to the system design. Such a complete tool chain allows to define and analyze the constellation behavior during the first project levels, when an important system engineering activity is required, in order to support system trade-offs and to determine the best system architecture to guarantee the largest coverage and capacity over the targeted countries. Hence these tools can be considered as very interesting prototypes for operational mission planning services too. The paper will illustrate all these principles by presenting the workshop architecture and by delivering several outputs and visualizations issued from the different tools. The use cases will be chosen among potential or fictitious architectures.

  3. 41 CFR 302-10.100 - What distance will my agency allow for points of origin and destination within CONUS and Alaska?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 4 2010-07-01 2010-07-01 false What distance will my... PRIMARY RESIDENCE Computation of Distance § 302-10.100 What distance will my agency allow for points of origin and destination within CONUS and Alaska? Your agency will allow for the distance shown in standard...

  4. 41 CFR 302-10.100 - What distance will my agency allow for points of origin and destination within CONUS and Alaska?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 41 Public Contracts and Property Management 4 2011-07-01 2011-07-01 false What distance will my... PRIMARY RESIDENCE Computation of Distance § 302-10.100 What distance will my agency allow for points of origin and destination within CONUS and Alaska? Your agency will allow for the distance shown in standard...

  5. 41 CFR 302-7.6 - What are the authorized origin and destination points for the transportation of HHG and PBP&E?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... origin and destination points for the transportation of HHG and PBP&E? 302-7.6 Section 302-7.6 Public... STORAGE OF PROPERTY 7-TRANSPORTATION AND TEMPORARY STORAGE OF HOUSEHOLD GOODS, PROFESSIONAL BOOKS, PAPERS, AND EQUIPMENT, (PBP&E) AND BAGGAGE ALLOWANCE General Rules § 302-7.6 What are the authorized...

  6. 41 CFR 302-9.206 - What should I do if there is no port or terminal at my authorized point of origin or authorized...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 4 2012-07-01 2012-07-01 false What should I do if there is no port or terminal at my authorized point of origin or authorized destination when I transport a POV from my post of duty? 302-9.206 Section 302-9.206 Public Contracts and Property...

  7. Development of Constellation's Launch Control System

    NASA Technical Reports Server (NTRS)

    Lougheed, Kirk D.; Peaden, Cary J.

    2010-01-01

    The paper focuses on the National Aeronautics and Space Administration (NASA) Constellation Program's Launch Control System (LCS) development effort at Kennedy Space Center (KSC). It provides a brief history of some preceding efforts to provide launch control and ground processing systems for other NASA programs, and some lessons learned from those experiences. It then provides high level descriptions of the LCS mission, objectives, organization, architecture, and progress. It discusses some of our development tenets, including our use of standards based design and use of off-the-shelf products whenever possible, incremental development cycles, and highly reliable, available, and supportable enterprise class system servers. It concludes with some new lessons learned and our plans for the future.

  8. Odyssey, a constellation for personal communications

    NASA Astrophysics Data System (ADS)

    Rusch, Roger J.; Cress, Peter; Horstein, Michael; Huang, Robert; Wiswell, Eric

    1992-03-01

    The Odyssey, designed to provide economical high-quality personal communication services from medium-altitude-orbit satellites, is described. Odyssey's services are to include: voice, data, paging, radio determination, and messaging. A constellation of 12 satellites will be orbited in three 55-deg inclined planes at an altitude of 10,354 km to provide continuous coverage of designated regions. Two satellites will be visible anywhere in the world at all times. This dual visiblity leads to high line-of-sight elevation angles, thereby minimizing obstructions by terrain, trees, and buildings. Each satellite generates a multibeam antenna pattern that divides its coverage area into a set of contiguous cells. The communications system architecture employs spread spectrum CDMA on both the uplinks and downlinks. This signaling method permits band sharing with other systems and applications. The lower power Odyssey handset will be cellular compatible. Multipath fade protection will be provided in the handset.

  9. Launching the Future... Constellation Program at KSC

    NASA Technical Reports Server (NTRS)

    Denson, Erik C.

    2010-01-01

    With the Constellation Program, NASA is entering a new age of space exploration that will take us back to the Moon, to Mars, and beyond, and NASA is developing the new technology and vehicles to take us there. At the forefront are the Orion spacecraft and the Ares I launch vehicle. As NASA's gateway to space, Kennedy Space Center (KSC) will process and launch the new vehicles. This will require new systems and extensive changes to existing infrastructure. KSC is designing a new mobile launcher, a new launch control system, and new ground support equipment; modifying the Vehicle Assembly Building, one of the launch pads, and other facilities; and launching the Ares I-X flight test. It is an exciting and challenging time to be an engineer at KSC.

  10. Electric Propulsion for Low Earth Orbit Constellations

    NASA Technical Reports Server (NTRS)

    Oleson, Steven R.; Sankovic, John M.

    1998-01-01

    Hall Effect electric propulsion was evaluated for orbit insertion, satellite repositioning, orbit maintenance and de-orbit applications for a sample low earth orbit satellite constellation. Since the low masses of these satellites enable multiple spacecraft per launch, the ability to add spacecraft to a given launch was used as a figure of merit. When compared to chemical propulsion, the Hall thruster system can add additional spacecraft per launch using planned payload power levels. One satellite can be added to the assumed four satellite baseline chemical launch without additional mission times. Two or three satellites may be added by providing part of the orbit insertion with the Hall system. In these cases orbit insertion times were found to be 35 and 62 days. Depending on the electric propulsion scenario, the resulting launch vehicle savings is nearly two, three or four Delta 7920 launch vehicles out of the chemical baseline scenarios eight Delta 7920 launch vehicles.

  11. Electric Propulsion for Low Earth Orbit Constellations

    NASA Technical Reports Server (NTRS)

    Oleson, Steven R.; Sankovic, John M.

    1998-01-01

    Hall effect electric propulsion was evaluated for orbit insertion, satellite repositioning, orbit maintenance and de-orbit applications for a sample low earth orbit satellite constellation. Since the low masses of these satellites enable multiple spacecraft per launch, the ability to add spacecraft to a given launch was used as a figure of merit. When compared to chemical propulsion, the Hall thruster system can add additional spacecraft per launch using planned payload power levels. One satellite can be added to the assumed four satellite baseline chemical launch without additional mission times. Two or three satellites may be added by providing part of the orbit insertion with the Hall system. In these cases orbit insertion times were found to be 35 and 62 days. Depending, on the electric propulsion scenario, the resulting launch vehicle savings is nearly two, three or four Delta 7920 launch vehicles out of the chemical baseline scenario's eight Delta 7920 launch vehicles.

  12. 2014_11_05_uss_constellation

    NASA Image and Video Library

    2017-09-27

    NASA’s Operation IceBridge collected some rare images on a flight out of Punta Arenas, Chile on Nov. 5, 2014, on a science flight over western Antarctica dubbed Ferrigno-Alison-Abbott 01. Following a routine calibration pass over Punta Arenas airport, the NASA DC-8 overflew the USS Constellation which is being towed for demolition after 53 yeas of service. The crew then snapped a few shots of a calving front of the Antarctic ice sheet. This particular flight plan was designed to collect data on changes in ice elevation along the coast near the Ferrigno and Alison ice streams, on the Abbot Ice Shelf, and grounded ice along the Eights Coast.

  13. Constellation X-Ray Mission and Support

    NASA Technical Reports Server (NTRS)

    Tananbaum, H.; Grady, Jean (Technical Monitor)

    2005-01-01

    This Final Report summarizes work performed by the Smithsonian Astrophysical Observatory (SAO) for NASA Goddard Space Flight Center (GSFC) under Cooperative Agreement NCC5-368. The Agreement is entitled "Constellation X-ray Mission Study and Support." The report covers the full duration of the Agreement which ran from October 1,1998 to October 14,2004. Included in the report is a description of previously unreported work that was performed between October 2003 and the end of the Agreement. For convenience, the previously unreported work is covered first in Section 2.0. Then, an overall summary of all work performed under the Agreement is presented in Section 3. Section 4.0 contains a list of all formal reports that SAO has submitted to GSFC along with publications and presentations at various conferences.

  14. Cubesat Constellation Design for Air Traffic Monitoring

    NASA Technical Reports Server (NTRS)

    Nag, Sreeja; Rios, Joseph Lucio; Gerhardt, David; Pham, Camvu

    2015-01-01

    Suitably equipped global and local air traffic can be tracked. The tracking information may then be used for control from ground-based stations by receiving the Automatic Dependent Surveillance-Broadcast (ADS-B) signal. The ADS-B signal, emitted from the aircraft's Mode-S transponder, is currently tracked by terrestrial based receivers but not over remote oceans or sparsely populated regions such as Alaska or the Pacific Ocean. Lack of real-time aircraft time/location information in remote areas significantly hinders optimal planning and control because bigger "safety bubbles" (lateral and vertical separation) are required around the aircraft until they reach radar-controlled airspace. Moreover, it presents a search-and-rescue bottleneck. Aircraft in distress, e.g. Air France AF449 that crashed in 2009, take days to be located or cannot be located at all, e.g. Malaysia Airlines MH370 in 2014. In this paper, we describe a tool for designing a constellation of small satellites which demonstrates, through high-fidelity modeling based on simulated air traffic data, the value of space-based ADS-B monitoring and provides recommendations for cost-efficient deployment of a constellation of small satellites to increase safety and situational awareness in the currently poorly-served surveillance area of Alaska. Air traffic data has been obtained from the Future ATM Concepts Evaluation Tool (FACET), developed at NASA Ames Research Center, simulated over the Alaskan airspace over a period of one day. The simulation is driven by MATLAB with satellites propagated and coverage calculated using AGI's Satellite ToolKit(STK10).

  15. Mean Density Estimation derived from Satellite Constellations

    NASA Astrophysics Data System (ADS)

    Li, A.; Close, S.

    2015-12-01

    With the advent of nanosatellite constellations, we define here a new method to derive neutral densities of the lower thermosphere from multiple similar platforms travelling through same regions of space. Because of similar orbits, the satellites are expected to encounter similar mean neutral densities and hence experience similar drag if their drag coefficients are equivalent. Utilizing free molecular flow theory to bound the minimum possible drag coefficient possible and order statistics to give a statistical picture of the distribution, we are able to estimate the neutral density alongside its associated error bounds. Data sources for this methodology can either be from already established Two Line Elements (TLEs) or from raw data sources, in which an additional filtering step needs to be performed to estimate relevant parameters. The effects of error in the filtering step of the methodology are also discussed and can be removed if the error distribution is Gaussian in nature. This method does not depend on prior models of the atmosphere, but instead is based upon physics models of simple shapes in free molecular flow. With a constellation of 10 satellites, we can achieve a standard deviation of roughly 4% on the estimated mean neutral density. As additional satellites are included in the estimation scheme, the result converges towards the lower limit of the achievable drag coefficient, and accuracy becomes limited by the quality of the ranging measurements and the probability of the accommodation coefficient. Data is provided courtesy of Planet Labs and comparisons are made to existing atmospheric models such as NRLMSISE-00 and JB2006.

  16. A mars communication constellation for human exploration and network science

    NASA Astrophysics Data System (ADS)

    Castellini, Francesco; Simonetto, Andrea; Martini, Roberto; Lavagna, Michèle

    2010-01-01

    Zenith Sea Launch rockets in March 2021 and carrying four satellites each. After the entrance in Mars sphere of influence, the single spacecrafts separate and spiral-down with Hall effect thrusters until they reach the final operational orbits in April 2025, at 17,030 km of altitude and 37 deg of inclination. The preliminary design includes 105 kg and 577 W of mass and power margin for each satellite, that can be allocated for scientific payloads. The main challenges of the proposed design are represented by the optical technology development and the connected strict pointing constraints satisfaction, as well as by the Martian constellation operations management. This mission study has therefore shown the possibility of deploying an effective communication infrastructure in Mars orbit employing a small amount of the resources needed for the human exploration programme, additionally providing the chance of performing important scientific research either from orbit or with a network of small rovers carried on-board and deployed on the surface.

  17. Amidst the Beauty of the Night Sky, Which of the Constellations am I?

    NASA Astrophysics Data System (ADS)

    Herrmann, Kimberly A.

    2011-01-01

    A well known constellation am I- I never set in the northern sky. Native Americans and Greeks, you see, Wrote legends when they recognized me. Two close stars still test for keen eyesight. Two point to the North Star - what a light! Look for my galaxies, you know where. I am ---- -----, the ----- ----! (If you've an answer you'd care to try, Or check out more riddles, please stop by! Note: All my astronomy riddles are copyrighted.)

  18. Micro-satellite constellations for monitoring cryospheric processes and related natural hazards

    NASA Astrophysics Data System (ADS)

    Kaeaeb, A.; Altena, B.; Mascaro, J.

    2016-12-01

    Currently, several micro-satellite constellations for earth-observation are planned or under build-up. Here, we assess the potential of the well-advanced Planet satellite constellation for investigating cryospheric processes. In its final stage, the Planet constellation will consist of 150 free-flying micro-satellites in near-polar and ISS orbits. The instruments carry RGB+NIR frame cameras that image the Earth surface in nadir direction with resolutions of 3-5 m, covering 20 x 13 km per image. In its final set-up, the constellation will be able to image the (almost) entire land surface at least once per day, under the limitation of cloud cover. Here, we explore new possibilities for insight into cryospheric processes that this very high repeat cycle combined with high image resolution offer. Based on repeat Planet imagery we derive repeat glacier velocity fields for example glaciers in the northern and southern hemispheres. We find it especially useful to monitor the ice velocities near calving fronts and simultaneously detect changes of the front, pointing to calving events. We also explore deformation fields over creeping mountain permafrost, so-called rockglaciers. As a second, very promising cryospheric application we suggest monitoring of glacier and permafrost related natural hazards. In cases such as temporary lakes, lake outbursts, landslides, rock avalanches, visual information over remote areas and at high frequencies are crucial for hazard assessment, early warning or disaster management. Based on several examples, we demonstrate that massive micro-satellite constellations such Planet's are exactly able to provide this type of information. As a third promising example, we show how such high-repeat optical satellite data are useful to monitor river ice and related jams and flooding. At certain latitudes, the repeat frequency of the data is even high enough to track river ice floes and thus water velocities.

  19. A satellite constellation optimization for a regional GNSS remote sensing mission

    NASA Astrophysics Data System (ADS)

    Gavili Kilaneh, Narin; Mashhadi Hossainali, Masoud

    2017-04-01

    Due to the recent advances in the Global Navigation Satellite System Remote sensing (GNSS¬R) applications, optimization of a satellite orbit to investigate the Earth's properties seems significant. The comparison of the GNSS direct and reflected signals received by a Low Earth Orbit (LEO) satellite introduces a new technique to remotely sense the Earth. Several GNSS¬R missions including Cyclone Global Navigation Satellite System (CYGNSS) have been proposed for different applications such as the ocean wind speed and height monitoring. The geometric optimization of the satellite orbit before starting the mission is a key step for every space mission. Since satellite constellation design varies depending on the application, we have focused on the required geometric criteria for oceanography applications in a specified region. Here, the total number of specular points, their spatial distribution and the accuracy of their position are assumed to be sufficient for oceanography applications. Gleason's method is used to determine the position of specular points. We considered the 2-D lattice and 3-D lattice theory of flower constellation to survey whether a circular orbit or an elliptical one is suitable to improve the solution. Genetic algorithm is implemented to solve the problem. To check the visibility condition between the LEO and GPS satellites, the satellite initial state is propagated by a variable step size numerical integration method. Constellation orbit parameters achieved by optimization provide a better resolution and precession for the specular points in the study area of this research.

  20. Design of two-dimensional signal constellations for visible light communication

    NASA Astrophysics Data System (ADS)

    Huang, Nuo; Wang, Jun-Bo; Zheng, Beixiong; Guan, Rui; Chen, Ming

    2017-02-01

    This paper investigates a two-dimensional signal space for visible light communication (VLC) by taking into account some practical constraints. We first present the relationship between the signal space and basis functions, and then find the basis function yielding the largest signal space. Besides, to improve the symbol error rate (SER) performance of the system, we design the constellations by maximizing the minimum Euclidean distance among all constellation pairs. The original optimization problem is non-convex and relaxed to a convex one through a linear approximation method. Simulation results show that the optimized design provides significant signal-to-noise ratio gain (up to 6 dB at the SER of 10-4 for half-illumination target) over the heuristic design.

  1. The Chinese hamster dihydrofolate reductase replication origin decision point follows activation of transcription and suppresses initiation of replication within transcription units.

    PubMed

    Sasaki, Takayo; Ramanathan, Sunita; Okuno, Yukiko; Kumagai, Chiharu; Shaikh, Seemab S; Gilbert, David M

    2006-02-01

    Chinese hamster ovary (CHO) cells select specific replication origin sites within the dihydrofolate reductase (DHFR) locus at a discrete point during G1 phase, the origin decision point (ODP). Origin selection is sensitive to transcription but not protein synthesis inhibitors, implicating a pretranslational role for transcription in origin specification. We have constructed a DNA array covering 121 kb surrounding the DHFR locus, to comprehensively investigate replication initiation and transcription in this region. When nuclei isolated within the first 3 h of G1 phase were stimulated to initiate replication in Xenopus egg extracts, replication initiated without any detectable preference for specific sites. At the ODP, initiation became suppressed from within the Msh3, DHFR, and 2BE2121 transcription units. Active transcription was mostly confined to these transcription units, and inhibition of transcription by alpha-amanitin resulted in the initiation of replication within transcription units, indicating that transcription is necessary to limit initiation events to the intergenic region. However, the resumption of DHFR transcription after mitosis took place prior to the ODP and so is not on its own sufficient to suppress initiation of replication. Together, these results demonstrate a remarkable flexibility in sequence selection for initiating replication and implicate transcription as one important component of origin specification at the ODP.

  2. The Chinese Hamster Dihydrofolate Reductase Replication Origin Decision Point Follows Activation of Transcription and Suppresses Initiation of Replication within Transcription Units

    PubMed Central

    Sasaki, Takayo; Ramanathan, Sunita; Okuno, Yukiko; Kumagai, Chiharu; Shaikh, Seemab S.; Gilbert, David M.

    2006-01-01

    Chinese hamster ovary (CHO) cells select specific replication origin sites within the dihydrofolate reductase (DHFR) locus at a discrete point during G1 phase, the origin decision point (ODP). Origin selection is sensitive to transcription but not protein synthesis inhibitors, implicating a pretranslational role for transcription in origin specification. We have constructed a DNA array covering 121 kb surrounding the DHFR locus, to comprehensively investigate replication initiation and transcription in this region. When nuclei isolated within the first 3 h of G1 phase were stimulated to initiate replication in Xenopus egg extracts, replication initiated without any detectable preference for specific sites. At the ODP, initiation became suppressed from within the Msh3, DHFR, and 2BE2121 transcription units. Active transcription was mostly confined to these transcription units, and inhibition of transcription by alpha-amanitin resulted in the initiation of replication within transcription units, indicating that transcription is necessary to limit initiation events to the intergenic region. However, the resumption of DHFR transcription after mitosis took place prior to the ODP and so is not on its own sufficient to suppress initiation of replication. Together, these results demonstrate a remarkable flexibility in sequence selection for initiating replication and implicate transcription as one important component of origin specification at the ODP. PMID:16428457

  3. Science and the Constellation Systems Program Office

    NASA Technical Reports Server (NTRS)

    Mendell, Wendell

    2007-01-01

    An underlying tension has existed throughout the history of NASA between the human spaceflight programs and the external scientific constituencies of the robotic exploration programs. The large human space projects have been perceived as squandering resources that might otherwise be utilized for scientific discoveries. In particular, the history of the relationship of science to the International Space Station Program has not been a happy one. The leadership of the Constellation Program Office, created in NASA in October, 2005, asked me to serve on the Program Manager s staff as a liaison to the science community. Through the creation of my position, the Program Manager wanted to communicate and elucidate decisions inside the program to the scientific community and, conversely, ensure that the community had a voice at the highest levels within the program. Almost all of my technical contributions at NASA, dating back to the Apollo Program, has been within the auspices of what is now known as the Science Mission Directorate. However, working at the Johnson Space Center, where human spaceflight is the principal activity, has given me a good deal of incidental contact and some more direct exposure through management positions to the structures and culture of human spaceflight programs. I entered the Constellation family somewhat naive but not uninformed. In addition to my background in NASA science, I have also written extensively over the past 25 years on the topic of human exploration of the Moon and Mars. (See, for example, Mendell, 1985). I have found that my scientific colleagues generally have little understanding of the structure and processes of a NASA program office; and many of them do not recognize the name, Constellation. In many respects, the international ILEWG community is better informed. Nevertheless, some NASA decision processes on the role of science, particularly with respect to the formulation of a lunar surface architecture, are not well known

  4. Science and the Constellation Systems Program Office

    NASA Technical Reports Server (NTRS)

    Mendell, Wendell

    2007-01-01

    An underlying tension has existed throughout the history of NASA between the human spaceflight programs and the external scientific constituencies of the robotic exploration programs. The large human space projects have been perceived as squandering resources that might otherwise be utilized for scientific discoveries. In particular, the history of the relationship of science to the International Space Station Program has not been a happy one. The leadership of the Constellation Program Office, created in NASA in October, 2005, asked me to serve on the Program Manager s staff as a liaison to the science community. Through the creation of my position, the Program Manager wanted to communicate and elucidate decisions inside the program to the scientific community and, conversely, ensure that the community had a voice at the highest levels within the program. Almost all of my technical contributions at NASA, dating back to the Apollo Program, has been within the auspices of what is now known as the Science Mission Directorate. However, working at the Johnson Space Center, where human spaceflight is the principal activity, has given me a good deal of incidental contact and some more direct exposure through management positions to the structures and culture of human spaceflight programs. I entered the Constellation family somewhat naive but not uninformed. In addition to my background in NASA science, I have also written extensively over the past 25 years on the topic of human exploration of the Moon and Mars. (See, for example, Mendell, 1985). I have found that my scientific colleagues generally have little understanding of the structure and processes of a NASA program office; and many of them do not recognize the name, Constellation. In many respects, the international ILEWG community is better informed. Nevertheless, some NASA decision processes on the role of science, particularly with respect to the formulation of a lunar surface architecture, are not well known

  5. Genetic analysis of emerald ash borer (Agrilus Planipennis Fairmaire) to determine point of origin in North American infestations

    Treesearch

    Jim Smith; Bob Haack; Leah Bauer

    2004-01-01

    The objective of this project is to estimate the geographic origin of emerald ash borer (EAB) populations in Asia that gave rise to EAB in North America. Knowledge of EAB genetics will be useful in understanding the invasion dynamics of the beetle, and to help identify geographic localities of potential biocontrol agents.

  6. RAD-seq data point to a northern origin of the arctic-alpine genus Cassiope (Ericaceae).

    PubMed

    Hou, Yan; Nowak, Michael D; Mirré, Virginia; Bjorå, Charlotte Sletten; Brochmann, Christian; Popp, Magnus

    2016-02-01

    Many arctic-alpine plants display a highly disjunct distribution between the Arctic/Boreal regions and the southern Asian mountains. Two main hypotheses have been proposed to explain the origin of this biogeographic pattern: (1) south-to-north migration in the late Pliocene/early Pleistocene, and (2) north-to-south migration during the Miocene. The genus Cassiope is disjunctly distributed between the Arctic/Boreal regions and the Himalayan-Hengduan Mountains (HHM) and was selected to test these hypotheses. We constructed a fossil-calibrated phylogeny of Ericaceae using two plastid regions to estimate the crown group age of Cassiope, and used sequence data from thousands of loci produced by restriction site associated DNA sequencing (RAD-seq) to reconstruct the phylogeny of Cassiope. We also performed Bayesian divergence time analysis and biogeographic analysis. The Cassiope crown group was estimated to have originated in the Miocene, which predates the onset of Northern hemisphere glaciation. All HHM species formed a clade together with one eastern Siberian species, and this clade was sister to all other Arctic/Boreal species. This topology implies a northern origin of Cassiope, which is confirmed by our biogeographic analysis. Our results thus suggest that the ancient north-to-south migration hypothesis is most consistent with the origin of Cassiope. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Satellite Constellation for Ocean Wind and Stress

    NASA Astrophysics Data System (ADS)

    Liu, W.; Xie, X.

    2009-12-01

    A scatterometer sends microwave pulses to the earth's surface and measure the power backscattered from the surface roughness. The roughness is believed to be in equilibrium with the stress (turbulent transport of momentum). The backscatter depends not only on the magnitude of the stress but also the stress direction relative to the direction of the radar beam. Measuring both stress magnitude and direction is the major unique capability of the scatterometer. Although stress drives ocean circulation, we do not have any large-scale stress measurement except from the scatterometer; our concept of stress distribution is largely derived from our knowledge on wind. Stress is closely related to wind. The geophysical product of the scatterometer is the equivalent neutral wind. It is a fictitious quantity, which has an unambiguous relation with surface stress by definition, while the relation between actual wind and surface stress depends on atmospheric vertical density stratification. Over most of the ocean, the atmosphere is near neutral and the current is much smaller than wind and it is generally assumed that the equivalent neutral wind is the actual wind. QuikSCAT, a Ku-band scatterometer, was launched in 1999. The scientific contributions to natural disaster, energy, weather, climate, water, ecosystem, and agriculture from one decade of QuikSCAT measurements will be presented. A C-band scatterometer, ASCAT, was launched by European Space Agency in 2006. Ku-band scatterometers, similar in design with QuikSCAT, will be launched by India and China in 2010 and 2011. One polar orbiting scatterometer could only sample the earth at most two times a day. If the future scatterometers will produce similarly high quality data, the future constellation of scatterometers, with different overhead crossing time, will meet the six hourly revisit frequency required by the operational weather forecast community and the inertial frequency required by research oceanographers. The coverage

  8. Does the Constellation Program Offer Opportunities to Achieve Space Science Goals in Space?

    NASA Technical Reports Server (NTRS)

    Thronson, Harley A.; Lester, Daniel F.; Dissel, Adam F.; Folta, David C.; Stevens, John; Budinoff, Jason G.

    2008-01-01

    Future space science missions developed to achieve the most ambitious goals are likely to be complex, large, publicly and professionally very important, and at the limit of affordability. Consequently, it may be valuable if such missions can be upgraded, repaired, and/or deployed in space, either with robots or with astronauts. In response to a Request for Information from the US National Research Council panel on Science Opportunities Enabled by NASA's Constellation System, we developed a concept for astronaut-based in-space servicing at the Earth-Moon L1,2 locations that may be implemented by using elements of NASA's Constellation architecture. This libration point jobsite could be of great value for major heliospheric and astronomy missions operating at Earth-Sun Lagrange points. We explored five alternative servicing options that plausibly would be available within about a decade. We highlight one that we believe is both the least costly and most efficiently uses Constellation hardware that appears to be available by mid-next decade: the Ares I launch vehicle, Orion/Crew Exploration Vehicle, Centaur vehicle, and an airlock/servicing node developed for lunar surface operations. Our concept may be considered similar to the Apollo 8 mission: a valuable exercise before descent by astronauts to the lunar surface.

  9. Guidance and Control System for a Satellite Constellation

    NASA Technical Reports Server (NTRS)

    Bryson, Jonathan Lamar; Cox, James; Mays, Paul Richard; Neidhoefer, James Christian; Ephrain, Richard

    2010-01-01

    A distributed guidance and control algorithm was developed for a constellation of satellites. The system repositions satellites as required, regulates satellites to desired orbits, and prevents collisions. 1. Optimal methods are used to compute nominal transfers from orbit to orbit. 2. Satellites are regulated to maintain the desired orbits once the transfers are complete. 3. A simulator is used to predict potential collisions or near-misses. 4. Each satellite computes perturbations to its controls so as to increase any unacceptable distances of nearest approach to other objects. a. The avoidance problem is recast in a distributed and locally-linear form to arrive at a tractable solution. b. Plant matrix values are approximated via simulation at each time step. c. The Linear Quadratic Gaussian (LQG) method is used to compute perturbations to the controls that will result in increased miss distances. 5. Once all danger is passed, the satellites return to their original orbits, all the while avoiding each other as above. 6. The delta-Vs are reasonable. The controller begins maneuvers as soon as practical to minimize delta-V. 7. Despite the inclusion of trajectory simulations within the control loop, the algorithm is sufficiently fast for available satellite computer hardware. 8. The required measurement accuracies are within the capabilities of modern inertial measurement devices and modern positioning devices.

  10. Probing Dark Energy with Constellation-X

    SciTech Connect

    Rapetti, David; Allen, Steven W.; /KIPAC, Menlo Park

    2006-09-08

    Constellation-X (Con-X) will carry out two powerful and independent sets of tests of dark energy based on X-ray observations of galaxy clusters, providing comparable accuracy to other leading dark energy probes. The first group of tests will measure the absolute distances to clusters, primarily using measurements of the X-ray gas mass fraction in the largest, dynamically relaxed clusters, but with additional constraining power provided by follow-up observations of the Sunyaev-Zel'dovich (SZ) effect. As with supernovae studies, such data determine the transformation between redshift and true distance, d(z), allowing cosmic acceleration to be measured directly. The second, independent group of tests will use the exquisite spectroscopic capabilities of Con-X to determine scaling relations between X-ray observables and mass. Together with forthcoming X-ray and SZ cluster surveys, these data will help to constrain the growth of structure, which is also a strong function of cosmological parameters.

  11. Visibility and Geometry of Glonass Constellation

    NASA Astrophysics Data System (ADS)

    Januszewski, Jacek

    2009-01-01

    Nowadays there are two worldwide satellite navigation systems - American GPS, fully operational and Russian GLONASS, no fully operational. The number of GLONASS satellites is less than nominal 24; in June 2009 spatial segment consists of 20 satellites, 18 operational and 2 in maintenance. The number of GLONASS satellites visible in open and restricted area, the distributions (in per cent) of the Geometric Dilution of Precision (GDOP) coefficient values and No Fix (without 3D position) for different numbers of GLONASS satellites (interval [18, 24]), for different masking elevation angles (interval [0°, 25°]) at different observer's latitudes (9 zones, each 10° wide), latitude of Poland (zone 50°-60°), in particular, are demonstrated in the paper. Additionally the detailed distributions of satellite azimuths (8 intervals, each 45° wide) and the percentage of satellite visible in open area above given angle at different latitudes for different numbers of satellites are showed. The knowledge of all these distributions are very important, especially after the publication of the U. S. Government report in which we can read that in 2010 the overall GPS constellation will fall below the number of satellites required the actual level of GPS position fix accuracy.

  12. Polar constellations design for discontinuous coverage

    NASA Astrophysics Data System (ADS)

    Sarno, Salvatore; Graziano, Maria Daniela; D'Errico, Marco

    2016-10-01

    A novel constellation design method is developed for discontinuous coverage of the globe and polar caps. It integrates and extends the applicability of the coverage regions and mitigates the limitations of the existing techniques based on streets-of-coverage (SOC) theory. In particular, the visibility conditions of the targets are mapped in the (Ω, u)-domain to identify the number of satellites per plane and the distance between successive orbits, whereas the planes are arranged around the equator exploiting satellites both in ascending and descending phase. The proposed approach is applied to design potential space segments in polar LEO supporting the existing maritime surveillance services over the globe and on the future polar routes. Results show they require a smaller total number of satellites with respect to the SOC-based configurations for revisit times less than one hour and wide range of swaths. In details, it is observed a reduction between 6% and 22% for global coverage and between 24% and 33% for the coverage of polar caps.

  13. Minimum of Geometric Dilution of Precision (GDOP) for five satellites with dual-GNSS constellations

    NASA Astrophysics Data System (ADS)

    Teng, Yunlong; Wang, Jinling; Huang, Qi

    2015-07-01

    The Geometric Dilution of Precision (GDOP) is a term to specify multiplicative effect of the satellite geometry on positioning and timing precision. For positioning, navigation and timing (PNT) applications with multi-GNSS constellations, the lower the GDOP values are, the more accurate the PNT solution is, and thus, the minimum value of GDOP should be discussed. Firstly, this paper analyses the traditional method for calculating the minimum of GDOP for dual-GNSS constellations. Then, from the point of the practical constraints of a GNSS receiver on the earth surface, a new formula for the specific minimum of GDOP together with the design matrix is derived. The minimum of GDOP is expressed as a function with two satellite elevation angles as variables. The numerical experiments have demonstrated the validation of the new formula for the minimum of GDOP.

  14. Constellation-masked secure communication technique for OFDM-PON.

    PubMed

    Liu, Bo; Zhang, Lijia; Xin, Xiangjun; Yu, Jianjun

    2012-10-22

    This paper proposes a novel secure communication technique using constellation masking for applications in orthogonal frequency division multiplexing passive optical network (OFDM-PON). The constellation masking is applied both on each subcarrier and among different subcarriers. The Arnold mapping is utilized as the parameter function for the mask factors. A interleave length is employed to provide a scalable masking granularity for different ONUs. A 15.54 Gb/s constellation-masked 32QAM-OFDM signal has been successfully transmitted over 25-km single mode fiber in the experiment. Experimental results show that the proposed scheme can effectively protect the system from illegal ONU without wasting the bandwidth. The constellation-masked technique suggests an effective solution for the physical secure communication in future OFDM access network.

  15. Analysis For Monitoring the Earth Science Afternoon Constellation

    NASA Technical Reports Server (NTRS)

    Demarest, Peter; Richon, Karen V.; Wright, Frank

    2005-01-01

    The Earth Science Afternoon Constellation consists of Aqua, Aura, PARASOL, CALIPSO, Cloudsat, and the Orbiting Carbon Observatory (OCO). The coordination of flight dynamics activities between these missions is critical to the safety and success of the Afternoon Constellation. This coordination is based on two main concepts, the control box and the zone-of-exclusion. This paper describes how these two concepts are implemented in the Constellation Coordination System (CCS). The CCS is a collection of tools that enables the collection and distribution of flight dynamics products among the missions, allows cross-mission analyses to be performed through a web-based interface, performs automated analyses to monitor the overall constellation, and notifies the missions of changes in the status of the other missions.

  16. The New Millenium Program ST-5 Mission: Nanosatellite Constellation Trailblazer

    NASA Technical Reports Server (NTRS)

    Slavin, James A.

    1999-01-01

    NASA's New Millenium Program has recently selected the Nanosatellite Constellation Trailblazer (NCT) as its fifth mission (ST-5). NCT will consist of 3 small, very capable and highly autonomous satellites which will be operated as a single "constellation" with minimal ground operations support. Each spacecraft will be approximately 40 cm in diameter by 20 cm in height and weigh only 20 kg. These small satellites will incorporate 8 new technologies essential to the further miniaturization of space science spacecraft which need space flight validation. In this talk we will describe in greater detail the NCT mission concept and goals, the exciting new technologies it will validate, and the role of miniaturized particles and fields sensors in this project. Finally, NCT's pathfinder function for such future NASA missions as Magnetotail Constellation and Inner Magnetosphere Constellation will be discussed.

  17. The New Millenium Program ST-5 Mission: Nanosatellite Constellation Trailblazer

    NASA Technical Reports Server (NTRS)

    Slavin, James A.

    1999-01-01

    NASA's New Millenium Program has recently selected the Nanosatellite Constellation Trailblazer (NCT) as its fifth mission (ST-5). NCT will consist of 3 small, very capable and highly autonomous satellites which will be operated as a single "constellation" with minimal ground operations support. Each spacecraft will be approximately 40 cm in diameter by 20 cm in height and weigh only 20 kg. These small satellites will incorporate 8 new technologies essential to the further miniaturization of space science spacecraft which need space flight validation. In this talk we will describe in greater detail the NCT mission concept and goals, the exciting new technologies it will validate, and the role of miniaturized particles and fields sensors in this project. Finally, NCT's pathfinder function for such future NASA missions as Magnetotail Constellation and Inner Magnetosphere Constellation will be discussed.

  18. A Mars Communication Constellation For Human Exploration and Network Science

    NASA Astrophysics Data System (ADS)

    Castellini, Francesco; Lavagna, Michèle; Simonetto, Andrea

    : particular attention has been paid in optimizing the mission analysis and identifying the best power generation solution. Attention has been also focused on the optical communication architecture, strictly connected with the precise attitude control. The resulting solution foresees two propulsion modules to be placed on a C3 0 escape orbit with two launches in March 2021, equipped with gridded ion thrusters capable of the 4.5 Km/s deltaV needed for the Earth-Mars transfer; each module carries four satellites until the entrance in Mars sphere of influence with near-zero relative velocity, where they separate and singularly spiral-down with their own Hall effect thrusters until they reach the final operational orbits, at 17030 km of altitude and 37 deg of inclination. The main challenges of the proposed design are represented by the optical technology development, the constellation operations management and the strict pointing constraints satisfaction imposed by the lasers. The subsystems design of both the spacecrafts and the electric propulsion buses are presented in the paper, that lead to a total margined mass of 3590 kg per launch. The overall constellation has been thought to be fitted into two Zenith SL rockets, that allow more than 410 kg of excess mass per launch, that can be allocated for scientific payloads. Moreover the power requirements of the Hall thrusters in the spiral-in phase largely exceed the total operational requirements, therefore more than 1 kW is available for science payloads on-board each spacecraft even at EOL, after 4 years of transfer and 10 years of operations, and at the maximum Sun-Mars distance. This mission study has therefore shown the possibility of deploying an effective communication infrastructure in Mars orbit employing a small amount of the resources needed for the human exploration programme; moreover the designed constellation of satellites would have enough power and mass margin to perform important scientific research from orbit

  19. Imaging Sensor Constellation for Tomographic Chemical Cloud Mapping

    DTIC Science & Technology

    2009-01-30

    a chemical cloud parallels the approach used in X-ray based medical imaging and can be an important tool in understanding chemical cloud dynamics...SR-1345 PSI-1505 Imaging Sensor Constellation for Tomographic Chemical Cloud Mapping Bogdan R. Cosofret,1,* Daisei Konno,1 Aram Faghfouri...00-00-2009 to 00-00-2009 4. TITLE AND SUBTITLE Imaging Sensor Constellation for Tomographic Chemical Cloud Mapping 5a. CONTRACT NUMBER 5b

  20. BRITE Constellation: data processing and photometry

    NASA Astrophysics Data System (ADS)

    Popowicz, A.; Pigulski, A.; Bernacki, K.; Kuschnig, R.; Pablo, H.; Ramiaramanantsoa, T.; Zocłońska, E.; Baade, D.; Handler, G.; Moffat, A. F. J.; Wade, G. A.; Neiner, C.; Rucinski, S. M.; Weiss, W. W.; Koudelka, O.; Orleański, P.; Schwarzenberg-Czerny, A.; Zwintz, K.

    2017-09-01

    Context. The BRIght Target Explorer (BRITE) mission is a pioneering space project aimed at the long-term photometric monitoring of the brightest stars in the sky by means of a constellation of nanosatellites. Its main advantage is high photometric accuracy and time coverage which are inaccessible from the ground. Its main drawback is the lack of cooling of the CCD detectors and the absence of good shielding that would protect them from energetic particles. Aims: The main aim of this paper is the presentation of procedures used to obtain high-precision photometry from a series of images acquired by the BRITE satellites in two modes of observing, stare and chopping. The other aim is a comparison of the photometry obtained with two different pipelines and a comparison of the real scatter with expectations. Methods: We developed two pipelines corresponding to the two modes of observing. They are based on aperture photometry with a constant aperture, circular for stare mode of observing and thresholded for chopping mode. Impulsive noise is a serious problem for observations made in the stare mode of observing and therefore in the pipeline developed for observations made in this mode, hot pixels are replaced using the information from shifted images in a series obtained during a single orbit of a satellite. In the other pipeline, the hot pixel replacement is not required because the photometry is made in difference images. Results: The assessment of the performance of both pipelines is presented. It is based on two comparisons, which use data from six runs of the UniBRITE satellite: (i) comparison of photometry obtained by both pipelines on the same data, which were partly affected by charge transfer inefficiency (CTI), (ii) comparison of real scatter with theoretical expectations. It is shown that for CTI-affected observations, the chopping pipeline provides much better photometry than the other pipeline. For other observations, the results are comparable only for data

  1. Space Technology 5: Enabling Future Micro-Sat Constellation Science Missions

    NASA Technical Reports Server (NTRS)

    Carlisle, Candace C.; Webb, Evan H.

    2004-01-01

    The Space Technology 5 (ST-5) Project is part of NASA s New Millennium Program. ST-5 will consist of a constellation of three micro-satellites, each approximately 25 kg in mass. The mission goals are to demonstrate the research-quality science capability of the ST-5 spacecraft; to operate the three spacecraft as a constellation; and to design, develop and flight-validate three capable micro-satellites with new technologies. ST-5 is designed to measurably raise the utility of small satellites by providing high functionality in a low mass, low power, and low volume package. The whole of ST-5 is greater than the sum of its parts: the collection of components into the ST-5 spacecraft allows it to perform the functionality of a larger scientific spacecraft on a micro-satellite platform. The ST-5 mission was originally designed to be launched as a secondary payload into a Geosynchronous Transfer Orbit (GTO). Recently, the mission has been replanned for a Pegasus XL dedicated launch into an elliptical polar orbit. A three-month flight demonstration phase, beginning in March 2006, will validate the ability to perform science measurements, as well as the technologies and constellation operations. ST- 5 s technologies and concepts will then be transferred to future micro-sat science missions.

  2. Space Technology 5: Enabling Future Micro-Sat Constellation Science Missions

    NASA Technical Reports Server (NTRS)

    Carlisle, Candace C.; Webb, Evan H.; Slavin, James A.

    2004-01-01

    The Space Technology 5 (ST-5) Project is part of NASA s New Millennium Program. ST-5 will consist of a constellation of three micro-satellites, each approximately 25 kg in mass. The mission goals are to demonstrate the research-quality science capability of the ST-5 spacecraft, to operate the three spacecraft as a constellation; and to design, develop and flight-validate three capable micro-satellites with new technologies. ST-5 is designed to measurably raise the utility of small satellites by providing high functionality in a low mass, low power, and low volume package. The whole of ST-5 is greater than the sum of its parts: the collection of components into the ST-5 spacecraft allows it to perform the functionality of a larger scientific spacecraft on a micro-satellite platform. The ST-5 mission was originally designed to be launched as a secondary payload into a Geosynchronous Transfer Orbit (GTO). Recently, the mission has been replanned for a Pegasus XL dedicated launch into an elliptical polar orbit. A three-month flight demonstration phase, beginning in March 2006, will validate the ability to perform science measurements, as well as the technologies and constellation operations. ST- 5 s technologies and concepts will then be transferred to future micro-sat science missions.

  3. Space Technology 5: Enabling Future Micro-Sat Constellation Science Missions

    NASA Technical Reports Server (NTRS)

    Carlisle, Candace C.; Webb, Evan H.; Slavin, James A.

    2004-01-01

    The Space Technology 5 (ST-5) Project is part of NASA s New Millennium Program. ST-5 will consist of a constellation of three micro-satellites, each approximately 25 kg in mass. The mission goals are to demonstrate the research-quality science capability of the ST-5 spacecraft, to operate the three spacecraft as a constellation; and to design, develop and flight-validate three capable micro-satellites with new technologies. ST-5 is designed to measurably raise the utility of small satellites by providing high functionality in a low mass, low power, and low volume package. The whole of ST-5 is greater than the sum of its parts: the collection of components into the ST-5 spacecraft allows it to perform the functionality of a larger scientific spacecraft on a micro-satellite platform. The ST-5 mission was originally designed to be launched as a secondary payload into a Geosynchronous Transfer Orbit (GTO). Recently, the mission has been replanned for a Pegasus XL dedicated launch into an elliptical polar orbit. A three-month flight demonstration phase, beginning in March 2006, will validate the ability to perform science measurements, as well as the technologies and constellation operations. ST- 5 s technologies and concepts will then be transferred to future micro-sat science missions.

  4. Human Rating Requirements for NASA's Constellation Program

    NASA Technical Reports Server (NTRS)

    Berdich, Debbie

    2008-01-01

    NASA s Constellation Program (CxP) will conduct a series of human space expeditions of increasing scope, starting with missions supporting the International Space Station and expanding to encompass the Moon and Mars. Although human-rating is an integral part of all CxP activities throughout their life cycle, NASA Procedural Requirements document NPR 8705.2B, Human-Rating Requirements (HRR) for Space Flight Systems, defines the additional processes, procedures, and requirements necessary to produce human-rated space systems that protect the safety of crew members and passengers on these NASA missions. In order to be in compliance with 8705.2B the CxP must show appropriate implementation or progression toward the HRR, or justification for an exception. Compliance includes an explanation of how the CxP intends to meet the HRR, analyses to be performed to determine implementation; and a matrix to trace the HRR to CxP requirements. The HRR requires the CxP to establish a human system integration team (HSIT), consisting of astronauts, mission operations personnel, training personnel, ground processing personnel, human factors personnel, and human engineering experts, with clearly defined authority, responsibility, and accountability to lead the human-system integration. For example, per the HRR the HSIT is involved in the evaluation of crew workload, human-in-the-loop usability evaluations, determining associated criteria, and in assessment of how these activities influenced system design. In essence, the HSIT is invaluable in CxP s ability to meet the three fundamental tenets of human rating: the process of designing, evaluating, and assuring that the total system can safely conduct the required human missions; the incorporation of design features and capabilities that accommodate human interaction with the system to enhance overall safety and mission success; and the incorporation of design features and capabilities to enable safe recovery of the crew from hazardous

  5. Human Rating Requirements for NASA's Constellation Program

    NASA Technical Reports Server (NTRS)

    Berdich, Debbie

    2008-01-01

    NASA s Constellation Program (CxP) will conduct a series of human space expeditions of increasing scope, starting with missions supporting the International Space Station and expanding to encompass the Moon and Mars. Although human-rating is an integral part of all CxP activities throughout their life cycle, NASA Procedural Requirements document NPR 8705.2B, Human-Rating Requirements (HRR) for Space Flight Systems, defines the additional processes, procedures, and requirements necessary to produce human-rated space systems that protect the safety of crew members and passengers on these NASA missions. In order to be in compliance with 8705.2B the CxP must show appropriate implementation or progression toward the HRR, or justification for an exception. Compliance includes an explanation of how the CxP intends to meet the HRR, analyses to be performed to determine implementation; and a matrix to trace the HRR to CxP requirements. The HRR requires the CxP to establish a human system integration team (HSIT), consisting of astronauts, mission operations personnel, training personnel, ground processing personnel, human factors personnel, and human engineering experts, with clearly defined authority, responsibility, and accountability to lead the human-system integration. For example, per the HRR the HSIT is involved in the evaluation of crew workload, human-in-the-loop usability evaluations, determining associated criteria, and in assessment of how these activities influenced system design. In essence, the HSIT is invaluable in CxP s ability to meet the three fundamental tenets of human rating: the process of designing, evaluating, and assuring that the total system can safely conduct the required human missions; the incorporation of design features and capabilities that accommodate human interaction with the system to enhance overall safety and mission success; and the incorporation of design features and capabilities to enable safe recovery of the crew from hazardous

  6. Geology of Nicholson's point granite, Natal Metamorphic Province, South Africa: the chemistry of charnockitic alteration and origin of the granite

    NASA Astrophysics Data System (ADS)

    Grantham, G. H.; Allen, A. R.; Cornell, D. H.; Harris, C.

    1996-10-01

    In the Port Edward area of southern Kwa-Zulu Natal, South Africa, charnockitic aureoles up to ˜4 m in width are developed adjacent to contacts with Port Edward enderbite and pegmatites intruded into the normally garnetiferous Nicholson's Point granite. Other mineralogical differences between the aureoles and the granite include increased myrmekite and significantly less biotite in the former and the replacement of pyrite by pyrrhotite in the charnockitic rocks. No significant differences in major element chemistry between the garnet-biotite Nicholson's Point granite and charnockitic Nicholson's Point granite are seen, except possibly for higher CaO and TiO 2 in the charnockite. Higher Rb, Th, Nb and Y contents in the garnet-biotite granite suggest that these elements have been locally depleted from garnet-biotite granite during char nockitisation. This depletion is considered to be related to the reduction in biotite. Strontium and Ba contents are significantly higher in the charnockite. Generally higher S contents in the charnockite suggest S metasomatism, with S possibly being added from the enderbite. No differences in δ18O isotope data are seen between the garnetiferous and hypersthene bearing granite. In the charnockite the LREEs are weakly depleted whereas the HREEs show greater depletion compared to the garnetiferous granite. The depletions in REEs are thought to be related to the breakdown of garnet. Europium is marginally enriched or unchanged in the charnockite relative to the garnetiferous granite. Two-pyroxene thermometry on the Port Edward enderbite suggests that it was intruded at temperatures of ˜1000-1100°C. The replacement of pyrite by pyrrhotite is also consistent with a thermal auroele. Consequently the charnockitic zones developed around the intrusions of Port Edward enderbite may result from the thermally driven dehydration of biotite. The aureoles developed adjacent to pegmatites are not considered to have resulted from heat but probably

  7. Test and Verification Approach for the NASA Constellation Program

    NASA Technical Reports Server (NTRS)

    Strong, Edward

    2008-01-01

    This viewgraph presentation is a test and verification approach for the NASA Constellation Program. The contents include: 1) The Vision for Space Exploration: Foundations for Exploration; 2) Constellation Program Fleet of Vehicles; 3) Exploration Roadmap; 4) Constellation Vehicle Approximate Size Comparison; 5) Ares I Elements; 6) Orion Elements; 7) Ares V Elements; 8) Lunar Lander; 9) Map of Constellation content across NASA; 10) CxP T&V Implementation; 11) Challenges in CxP T&V Program; 12) T&V Strategic Emphasis and Key Tenets; 13) CxP T&V Mission & Vision; 14) Constellation Program Organization; 15) Test and Evaluation Organization; 16) CxP Requirements Flowdown; 17) CxP Model Based Systems Engineering Approach; 18) CxP Verification Planning Documents; 19) Environmental Testing; 20) Scope of CxP Verification; 21) CxP Verification - General Process Flow; 22) Avionics and Software Integrated Testing Approach; 23) A-3 Test Stand; 24) Space Power Facility; 25) MEIT and FEIT; 26) Flight Element Integrated Test (FEIT); 27) Multi-Element Integrated Testing (MEIT); 28) Flight Test Driving Principles; and 29) Constellation s Integrated Flight Test Strategy Low Earth Orbit Servicing Capability.

  8. Structural molecular components of septate junctions in cnidarians point to the origin of epithelial junctions in eukaryotes.

    PubMed

    Ganot, Philippe; Zoccola, Didier; Tambutté, Eric; Voolstra, Christian R; Aranda, Manuel; Allemand, Denis; Tambutté, Sylvie

    2015-01-01

    Septate junctions (SJs) insure barrier properties and control paracellular diffusion of solutes across epithelia in invertebrates. However, the origin and evolution of their molecular constituents in Metazoa have not been firmly established. Here, we investigated the genomes of early branching metazoan representatives to reconstruct the phylogeny of the molecular components of SJs. Although Claudins and SJ cytoplasmic adaptor components appeared successively throughout metazoan evolution, the structural components of SJs arose at the time of Placozoa/Cnidaria/Bilateria radiation. We also show that in the scleractinian coral Stylophora pistillata, the structural SJ component Neurexin IV colocalizes with the cortical actin network at the apical border of the cells, at the place of SJs. We propose a model for SJ components in Cnidaria. Moreover, our study reveals an unanticipated diversity of SJ structural component variants in cnidarians. This diversity correlates with gene-specific expression in calcifying and noncalcifying tissues, suggesting specific paracellular pathways across the cell layers of these diploblastic animals.

  9. Origin of electrochemical activity in nano-Li2MnO3; stabilization via a `point defect scaffold'

    NASA Astrophysics Data System (ADS)

    Sayle, Thi X. T.; Caddeo, Francesco; Monama, Nkwe O.; Kgatwane, Kenneth M.; Ngoepe, Phuti E.; Sayle, Dean C.

    2014-12-01

    Molecular dynamics (MD) simulations of the charging of Li2MnO3 reveal that the reason nanocrystalline-Li2MnO3 is electrochemically active, in contrast to the parent bulk-Li2MnO3, is because in the nanomaterial the tunnels, in which the Li ions reside, are held apart by Mn ions, which act as a pseudo `point defect scaffold'. The Li ions are then able to diffuse, via a vacancy driven mechanism, throughout the nanomaterial in all spatial dimensions while the `Mn defect scaffold' maintains the structural integrity of the layered structure during charging. Our findings reveal that oxides, which comprise cation disorder, can be potential candidates for electrodes in rechargeable Li-ion batteries. Moreover, we propose that the concept of a `point defect scaffold' might manifest as a more general phenomenon, which can be exploited to engineer, for example, two or three-dimensional strain within a host material and can be fine-tuned to optimize properties, such as ionic conductivity.

  10. Origins Rock Art and Calendar in Armenia and Anania Shirakatsi

    NASA Astrophysics Data System (ADS)

    Tokhatyan, Karen

    2014-10-01

    A review on the origin of rock art and calendars in Armenia, as well as Anania Shirakatsi's views are given. Astronomy and calendar, formation of the constellations, types of calendars, the Armenian ancient calendar, Armenian Hayk/Orion constellation and corresponding mythological heroes, and further phases of the Armenian calendar are discussed.

  11. 75 FR 2163 - Constellation Energy; Notice of Docketing of Special Nuclear Material License SNM-2505 Amendment...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-14

    ... COMMISSION Constellation Energy; Notice of Docketing of Special Nuclear Material License SNM-2505 Amendment... June 15, 2009, from Constellation Energy (Constellation) to amend its Special Nuclear Material License... will remain the same for this action. An NRC review, documented in a letter to Constellation dated...

  12. Role of fluid mixing and fault-related sulfide in the origin of the Ray Point uranium district, south Texas.

    USGS Publications Warehouse

    Goldhaber, M.B.; Reynolds, R.L.; Rye, R.O.

    1983-01-01

    The Lamprecht and Felder deposits are two of many roll-type uranium deposits hosted by the Miocene Oakville sandstone in the Ray Point district, Live Oak County, S Texas. Both deposits show similar patterns of geochemical zonation and distribution of authigenic iron disulphide minerals, and both appear to be genetically related to the nearby Oakville fault. Distribution of U, Mo and Se are typical of roll-type deposits. Sulphur isotope data indicate four stages of FeS2 mineral formation. Geochemical data suggest that the host sandstone near the Oakville fault is the site of a complex zone of mixing between fault-derived saline brines and oxygenated meteoric water. Conditions were thus provided in this zone for the proliferation of sulphate-reducing bacteria that in turn gave rise to the ore mineralization. A detailed discussion of the geological evolution of these deposits is presented.-J.E.S.

  13. Symbolics of the constellations of sagittarius and centaurus in russian traditional culture

    NASA Astrophysics Data System (ADS)

    Bagdasarov, R.

    2001-12-01

    Centaurus falls into the category of 'imaginary animals'. The Russian tradition used not only the symbol Sgr (a result of its acquaintance with the circle of Zodiac), but also the symbol Cen, which fact, as we shall demonstrate, is an evidence of certain mythological-astronomical conceptions. Both the constellations Sagittarius (Sgr) and Centaurus (Cen) are usually represented as versions of the picture of a fantastic being, a Centaur, shaped as man from head to waist, and as an animal, mostly, a horse, from waist down. 'Centaurus' (from the Greek word kev (or kevw)) for 'kill' and o, for 'bull') means 'bull killer', and is probably related to the opposition of the zodiacal constellations Taurus and Sagittarius. When the latter begins to rise on to the night sky, the former disappears completely from view. Sagittarius is represented at ancient monuments related to astronomy as a centaur holding a bow and pointing at certain stars. The constellation of Centaurus is also symbolised by a centaur, but holding not a bow, but a staff or a spear in one hand and an 'animal of sacrifice' in the other (Higinus, Astronomica, III, 37, 1; Chernetsov, 1975, Figure 1). The attributes stand for the Peliases Spear (The Mithological Dictionary, 1991), depicted in astrological maps as The Spear of Centaurus1, The Wolf (Lupus), the Panther or the Beast (Flammarion, 1994).

  14. Mathematical minimum of Geometric Dilution of Precision (GDOP) for dual-GNSS constellations

    NASA Astrophysics Data System (ADS)

    Teng, Yunlong; Wang, Jinling; Huang, Qi

    2016-01-01

    Selecting optimal satellites for positioning calculation is a basic problem for the positioning, navigation and timing (PNT) applications with Global Navigation Satellite System (GNSS), and the Geometric Dilution of Precision (GDOP) is a key index to handle this problem. In general, the lower the GDOP values are, the more accurate the PNT solution is. Therefore, the minimum value of GDOP should be pursued. In this paper, we focused on the five-satellite as at least five satellites are required for dual-GNSS constellations. Utilizing the characteristics of matrix partial orders, the mathematical minimum of GDOP in the five-satellite case together with the optimal distribution of the five satellites has been theoretically derived. Furthermore, from a theoretical point of view, the detailed expressions of the impact of different constellational combinations of these satellites on the GDOP have been obtained. The results demonstrated that, for dual-GNSS, even if the geometric distribution of the five satellites is fixed, different constellational combinations of these satellites lead to different values of GDOP. This is different from the single-GNSS case.

  15. Amidst the Beauty of the Night Sky, which of the Constellations am I?

    NASA Astrophysics Data System (ADS)

    Herrmann, K. A.

    2012-08-01

    A well known constellation am I- I never set in the northern sky. Native Americans and Greeks, you see, Wrote legends when they recognized me. Two close stars still test for keen eyesight. Two point to the North Star - what a light! Look for my galaxies, you know where. I am ____ _____, the _____ ____! © Kimberly A. Herrmann, 2003) I have loved rhyming poetry ever since I can remember - from Dr. Seuss's Green Eggs and Ham and Maurice Sendak's Chicken Soup with Rice, to the works of Shel Silverstein and Jack Prelutsky. It was not until high school, though, that I realized that I could combine two of my loves - those for poetry and astronomy. Since then, I have written almost 100 astronomical riddles and always attempted to include as much astronomy content as possible - even in the riddles about constellations. Consequently, I have found them effective in teaching or reviewing aspects of astronomy in several venues, including college astronomy courses for non-science majors and events with elementary school students. More recently I have used 23 constellation riddles to create informative and entertaining seating slides that have been playing at Lowell Observatory and the Youngstown Planetarium. I hope to have these slides played at other venues as well and also hope to publish my riddles as a series of books someday.

  16. The Availability of Space Service for Inter-Satellite Links in Navigation Constellations.

    PubMed

    Tang, Yinyin; Wang, Yueke; Chen, Jianyun

    2016-08-19

    Global navigation satellite systems (GNSS) are widely used in low Earth orbit (LEO) satellite navigation; however, their availability is poor for users in medium Earth orbits (MEO), and high Earth orbits (HEO). With the increasing demand for navigation from MEO and HEO users, the inadequate coverage of GNSS has emerged. Inter-satellite links (ISLs) are used for ranging and communication between navigation satellites and can also serve space users that are outside the navigation constellation. This paper aims to summarize their application method and analyze their service performance. The mathematical model of visibility is proposed and then the availability of time division ISLs is analyzed based on global grid points. The BeiDou navigation constellation is used as an example for numerical simulation. Simulation results show that the availability can be enhanced by scheduling more satellites and larger beams, while the presence of more users lowers the availability. The availability of navigation signals will be strengthened when combined with the signals from the ISLs. ISLs can improve the space service volume (SSV) of navigation constellations, and are therefore a promising method for navigation in MEO/HEO spacecraft.

  17. Linking Satellites Via Earth "Hot Spots" and the Internet to Form Ad Hoc Constellations

    NASA Technical Reports Server (NTRS)

    Mandl, Dan; Frye, Stu; Grosvenor, Sandra; Ingram, Mary Ann; Langley, John; Miranda, Felix; Lee, Richard Q.; Romanofsky, Robert; Zaman, Afoz; Popovic, Zoya

    2004-01-01

    As more assets are placed in orbit, opportunities emerge to combine various sets of satellites in temporary constellations to perform collaborative image collections. Often, new operations concepts for a satellite or set of satellites emerge after launch. To the degree with which new space assets can be inexpensively and rapidly integrated into temporary or "ad hoc" constellations, will determine whether these new ideas will be implemented or not. On the Earth Observing 1 (EO-1) satellite, a New Millennium Program mission, a number of experiments were conducted and are being conducted to demonstrate various aspects of an architecture that, when taken as a whole, will enable progressive mission autonomy. In particular, the target architecture will use adaptive ground antenna arrays to form, as close as possible, the equivalent of wireless access points for low earth orbiting satellites. Coupled with various ground and flight software and the Internet. the architecture enables progressive mission autonomy. Thus, new collaborative sensing techniques can be implemented post-launch. This paper will outline the overall operations concept and highlight details of both the research effort being conducted in constellations, mission autonomy and

  18. The Availability of Space Service for Inter-Satellite Links in Navigation Constellations

    PubMed Central

    Tang, Yinyin; Wang, Yueke; Chen, Jianyun

    2016-01-01

    Global navigation satellite systems (GNSS) are widely used in low Earth orbit (LEO) satellite navigation; however, their availability is poor for users in medium Earth orbits (MEO), and high Earth orbits (HEO). With the increasing demand for navigation from MEO and HEO users, the inadequate coverage of GNSS has emerged. Inter-satellite links (ISLs) are used for ranging and communication between navigation satellites and can also serve space users that are outside the navigation constellation. This paper aims to summarize their application method and analyze their service performance. The mathematical model of visibility is proposed and then the availability of time division ISLs is analyzed based on global grid points. The BeiDou navigation constellation is used as an example for numerical simulation. Simulation results show that the availability can be enhanced by scheduling more satellites and larger beams, while the presence of more users lowers the availability. The availability of navigation signals will be strengthened when combined with the signals from the ISLs. ISLs can improve the space service volume (SSV) of navigation constellations, and are therefore a promising method for navigation in MEO/HEO spacecraft. PMID:27548181

  19. Linking Satellites Via Earth "Hot Spots" and the Internet to Form Ad Hoc Constellations

    NASA Technical Reports Server (NTRS)

    Mandl, Dan; Frye, Stu; Grosvenor, Sandra; Ingram, Mary Ann; Langley, John; Miranda, Felix; Lee, Richard Q.; Romanofsky, Robert; Zaman, Afoz; Popovic, Zoya

    2004-01-01

    As more assets are placed in orbit, opportunities emerge to combine various sets of satellites in temporary constellations to perform collaborative image collections. Often, new operations concepts for a satellite or set of satellites emerge after launch. To the degree with which new space assets can be inexpensively and rapidly integrated into temporary or "ad hoc" constellations, will determine whether these new ideas will be implemented or not. On the Earth Observing 1 (EO-1) satellite, a New Millennium Program mission, a number of experiments were conducted and are being conducted to demonstrate various aspects of an architecture that, when taken as a whole, will enable progressive mission autonomy. In particular, the target architecture will use adaptive ground antenna arrays to form, as close as possible, the equivalent of wireless access points for low earth orbiting satellites. Coupled with various ground and flight software and the Internet. the architecture enables progressive mission autonomy. Thus, new collaborative sensing techniques can be implemented post-launch. This paper will outline the overall operations concept and highlight details of both the research effort being conducted in constellations, mission autonomy and

  20. RapidEye constellation relative radiometric accuracy measurement using lunar images

    NASA Astrophysics Data System (ADS)

    Steyn, Joe; Tyc, George; Beckett, Keith; Hashida, Yoshi

    2009-09-01

    The RapidEye constellation includes five identical satellites in Low Earth Orbit (LEO). Each satellite has a 5-band (blue, green, red, red-edge and near infrared (NIR)) multispectral imager at 6.5m GSD. A three-axes attitude control system allows pointing the imager of each satellite at the Moon during lunations. It is therefore possible to image the Moon from near identical viewing geometry within a span of 80 minutes with each one of the imagers. Comparing the radiometrically corrected images obtained from each band and each satellite allows a near instantaneous relative radiometric accuracy measurement and determination of relative gain changes between the five imagers. A more traditional terrestrial vicarious radiometric calibration program has also been completed by MDA on RapidEye. The two components of this program provide for spatial radiometric calibration ensuring that detector-to-detector response remains flat, while a temporal radiometric calibration approach has accumulated images of specific dry dessert calibration sites. These images are used to measure the constellation relative radiometric response and make on-ground gain and offset adjustments in order to maintain the relative accuracy of the constellation within +/-2.5%. A quantitative comparison between the gain changes measured by the lunar method and the terrestrial temporal radiometric calibration method is performed and will be presented.

  1. Intelligent constellation diagram analyzer using convolutional neural network-based deep learning.

    PubMed

    Wang, Danshi; Zhang, Min; Li, Jin; Li, Ze; Li, Jianqiang; Song, Chuang; Chen, Xue

    2017-07-24

    An intelligent constellation diagram analyzer is proposed to implement both modulation format recognition (MFR) and optical signal-to-noise rate (OSNR) estimation by using convolution neural network (CNN)-based deep learning technique. With the ability of feature extraction and self-learning, CNN can process constellation diagram in its raw data form (i.e., pixel points of an image) from the perspective of image processing, without manual intervention nor data statistics. The constellation diagram images of six widely-used modulation formats over a wide OSNR range (15~30 dB and 20~35 dB) are obtained from a constellation diagram generation module in oscilloscope. Both simulation and experiment are conducted. Compared with other 4 traditional machine learning algorithms, CNN achieves the better accuracies and is obviously superior to other methods at the cost of O(n) computation complexity and less than 0.5 s testing time. For OSNR estimation, the high accuracies are obtained at epochs of 200 (95% for 64QAM, and over 99% for other five formats); for MFR, 100% accuracies are achieved even with less training data at lower epochs. The experimental results show that the OSNR estimation errors for all the signals are less than 0.7 dB. Additionally, the effects of multiple factors on CNN performance are comprehensively investigated, including the training data size, image resolution, and network structure. The proposed technique has the potential to be embedded in the test instrument to perform intelligent signal analysis or applied for optical performance monitoring.

  2. Evaluation of the existing triple point path models with new experimental data: proposal of an original empirical formulation

    NASA Astrophysics Data System (ADS)

    Boutillier, J.; Ehrhardt, L.; De Mezzo, S.; Deck, C.; Magnan, P.; Naz, P.; Willinger, R.

    2017-08-01

    With the increasing use of improvised explosive devices (IEDs), the need for better mitigation, either for building integrity or for personal security, increases in importance. Before focusing on the interaction of the shock wave with a target and the potential associated damage, knowledge must be acquired regarding the nature of the blast threat, i.e., the pressure-time history. This requirement motivates gaining further insight into the triple point (TP) path, in order to know precisely which regime the target will encounter (simple reflection or Mach reflection). Within this context, the purpose of this study is to evaluate three existing TP path empirical models, which in turn are used in other empirical models for the determination of the pressure profile. These three TP models are the empirical function of Kinney, the Unified Facilities Criteria (UFC) curves, and the model of the Natural Resources Defense Council (NRDC). As discrepancies are observed between these models, new experimental data were obtained to test their reliability and a new promising formulation is proposed for scaled heights of burst ranging from 24.6-172.9 cm/kg^{1/3}.

  3. Streamlining the Design Tradespace for Earth Imaging Constellations

    NASA Technical Reports Server (NTRS)

    Nag, Sreeja; Hughes, Steven P.; Le Moigne, Jacqueline J.

    2016-01-01

    Satellite constellations and Distributed Spacecraft Mission (DSM) architectures offer unique benefits to Earth observation scientists and unique challenges to cost estimators. The Cost and Risk (CR) module of the Tradespace Analysis Tool for Constellations (TAT-C) being developed by NASA Goddard seeks to address some of these challenges by providing a new approach to cost modeling, which aggregates existing Cost Estimating Relationships (CER) from respected sources, cost estimating best practices, and data from existing and proposed satellite designs. Cost estimation through this tool is approached from two perspectives: parametric cost estimating relationships and analogous cost estimation techniques. The dual approach utilized within the TAT-C CR module is intended to address prevailing concerns regarding early design stage cost estimates, and offer increased transparency and fidelity by offering two preliminary perspectives on mission cost. This work outlines the existing cost model, details assumptions built into the model, and explains what measures have been taken to address the particular challenges of constellation cost estimating. The risk estimation portion of the TAT-C CR module is still in development and will be presented in future work. The cost estimate produced by the CR module is not intended to be an exact mission valuation, but rather a comparative tool to assist in the exploration of the constellation design tradespace. Previous work has noted that estimating the cost of satellite constellations is difficult given that no comprehensive model for constellation cost estimation has yet been developed, and as such, quantitative assessment of multiple spacecraft missions has many remaining areas of uncertainty. By incorporating well-established CERs with preliminary approaches to approaching these uncertainties, the CR module offers more complete approach to constellation costing than has previously been available to mission architects or Earth

  4. Feline Origin of Rotavirus Strain, Tunisia, 2008

    PubMed Central

    Fredj, Mouna Ben Hadj; Heylen, Elisabeth; Zeller, Mark; Fodha, Imene; Benhamida-Rebai, Meriam; Van Ranst, Marc; Matthijnssens, Jelle

    2013-01-01

    In Tunisia in 2008, an unusual G6P[9] rotavirus, RVA/human-wt/TUN/17237/2008/G6P[9], rarely found in humans, was detected in a child. To determine the origin of this strain, we conducted phylogenetic analyses and found a unique genotype constellation resembling rotaviruses belonging to the feline BA222-like genotype constellation. The strain probably resulted from direct cat-to-human transmission. PMID:23631866

  5. Elimination of infusion bubbles and uncontrolled reflux in the alcon constellation vitrectomy vision system.

    PubMed

    Russell, Stephen R; Sohn, Elliott H; Boldt, H Culver; Folk, James C; Tarantola, Ryan M; Kay, Christine N; Mahajan, Vinit B

    2013-04-01

    To identify the sources and management of 2 problems associated with the Alcon Constellation Vitrectomy (Alcon Laboratories, Inc) System: 1) infusion bubbles and 2) uncontrolled reflux. Surgical and analytical videos were evaluated to identify the source of intraoperative bubbles, which localized to the duckbill valve (DV). Intraoperatively, the authors modified the infusion tubing and its control by removing the DV. The DV was repurposed as a one-way valve to block reflux originating from the vitrectomy console. Twenty consecutive 23-gauge vitrectomies in 20 eyes of 20 subjects from 2 surgeons (S.R.R. and E.H.S.) were reviewed. Infusion bubbles at the DV developed with each transitory tubing pressure drop upon opening of the infusion clamp. Removal of the DV from the infusion line eliminated infusion bubbles in 20 consecutive 23-gauge cases. Adding a one-way valve, which was fashioned from the DV, to the aspiration tubing, resulted in elimination of infusion bubbles and console-originated reflux in 20 eyes. Placement of the DV to block reflux eliminated both uncontrolled and purposeful console-originated reflux. Intraoperative modification of Constellation tubing may eliminate two potentially harmful problems until manufacturer correction is instituted. Because the authors' modified connections represent off-label connectivity, the manufacturer cannot contact potentially affected surgeons or suggest temporary alternative connectivity improvements.

  6. Dark Energy, Dark Matter and Science with Constellation-X

    NASA Technical Reports Server (NTRS)

    Cardiff, Ann Hornschemeier

    2005-01-01

    Constellation-X, with more than 100 times the collecting area of any previous spectroscopic mission operating in the 0.25-40 keV bandpass, will enable highthroughput, high spectral resolution studies of sources ranging from the most luminous accreting supermassive black holes in the Universe to the disks around young stars where planets form. This talk will review the updated Constellation-X science case, released in booklet form during summer 2005. The science areas where Constellation-X will have major impact include the exploration of the space-time geometry of black holes spanning nine orders of magnitude in mass and the nature of the dark energy and dark matter which govern the expansion and ultimate fate of the Universe. Constellation-X will also explore processes referred to as "cosmic feedback" whereby mechanical energy, radiation, and chemical elements from star formation and black holes are returned to interstellar and intergalactic medium, profoundly affecting the development of structure in the Universe, and will also probe all the important life cycles of matter, from stellar and planetary birth to stellar death via supernova to stellar endpoints in the form of accreting binaries and supernova remnants. This talk will touch upon all these areas, with particular emphasis on Constellation-X's role in the study of Dark Energy.

  7. Dark Energy, Dark Matter and Science with Constellation-X

    NASA Technical Reports Server (NTRS)

    Cardiff, Ann Hornschemeier

    2005-01-01

    Constellation-X, with more than 100 times the collecting area of any previous spectroscopic mission operating in the 0.25-40 keV bandpass, will enable highthroughput, high spectral resolution studies of sources ranging from the most luminous accreting supermassive black holes in the Universe to the disks around young stars where planets form. This talk will review the updated Constellation-X science case, released in booklet form during summer 2005. The science areas where Constellation-X will have major impact include the exploration of the space-time geometry of black holes spanning nine orders of magnitude in mass and the nature of the dark energy and dark matter which govern the expansion and ultimate fate of the Universe. Constellation-X will also explore processes referred to as "cosmic feedback" whereby mechanical energy, radiation, and chemical elements from star formation and black holes are returned to interstellar and intergalactic medium, profoundly affecting the development of structure in the Universe, and will also probe all the important life cycles of matter, from stellar and planetary birth to stellar death via supernova to stellar endpoints in the form of accreting binaries and supernova remnants. This talk will touch upon all these areas, with particular emphasis on Constellation-X's role in the study of Dark Energy.

  8. Design of a micro-satellite constellation for communication

    NASA Astrophysics Data System (ADS)

    Ma, Der-Ming; Hong, Zuu-Chang; Lee, Tzung-Hang; Chang, Bo-Jyun

    2013-01-01

    The purpose of this paper is to present a low Earth orbit constellation which provides a communication function over a region centered in Taiwan, with radii of 500 km, 1000 km, 1500 km, 2000 km and 2500 km, and orbit altitudes of 800 km and 1500 km. Several constellations are studied. Two constellations with satellite orbit altitudes of only 800 km or 1000 km are considered first. The results that are obtained show that 27 satellites are required for an orbit altitude of 800 km and 15 satellites for an orbit altitude of 1500 km. The asymmetrical nature of constellations is also presented. The first case presents the results when a single inclination angle is used. For example, covering the region with a radius of 2000 km, 20 satellites orbiting at altitudes of 1500 km and 10 satellites orbiting at altitudes of 800 km with inclinations of 35° are required. In the second case examining the asymmetrical nature of constellations, two inclinations angles are used. For example, covering the region with a radius of 2000 km, 20 satellites orbiting at altitudes of 1500 km with inclinations of 35° and 9 satellites orbiting at altitudes of 800 km with inclinations of 30° are required.

  9. Constellation Pharmacology: A new paradigm for drug discovery

    PubMed Central

    Schmidt, Eric W.; Olivera, Baldomero M.

    2015-01-01

    Constellation Pharmacology is a cell-based high-content phenotypic-screening platform that utilizes subtype-selective pharmacological agents to elucidate the cell-specific combinations (“constellations”) of key signaling proteins that define specific cell types. Heterogeneous populations of native cells, in which the different individual cell types have been identified and characterized, are the foundation for this screening platform. Constellation Pharmacology is useful for screening small molecules or for deconvoluting complex mixtures of biologically-active natural products. This platform has been used to purify natural products and discover their molecular mechanisms. In the on-going development of Constellation Pharmacology, there is a positive-feedback loop between the pharmacological characterization of cell types and screening for new drug candidates. As Constellation Pharmacology is used to discover compounds with novel targeting-selectivity profiles, those new compounds then further help to elucidate the constellations of specific cell types, thereby increasing the content of this high-content platform. PMID:25562646

  10. Optimizing the Attitude Control of Small Satellite Constellations for Rapid Response Imaging

    NASA Astrophysics Data System (ADS)

    Nag, S.; Li, A.

    2016-12-01

    Distributed Space Missions (DSMs) such as formation flight and constellations, are being recognized as important solutions to increase measurement samples over space and time. Given the increasingly accurate attitude control systems emerging in the commercial market, small spacecraft now have the ability to slew and point within few minutes of notice. In spite of hardware development in CubeSats at the payload (e.g. NASA InVEST) and subsystems (e.g. Blue Canyon Technologies), software development for tradespace analysis in constellation design (e.g. Goddard's TAT-C), planning and scheduling development in single spacecraft (e.g. GEO-CAPE) and aerial flight path optimizations for UAVs (e.g. NASA Sensor Web), there is a gap in open-source, open-access software tools for planning and scheduling distributed satellite operations in terms of pointing and observing targets. This paper will demonstrate results from a tool being developed for scheduling pointing operations of narrow field-of-view (FOV) sensors over mission lifetime to maximize metrics such as global coverage and revisit statistics. Past research has shown the need for at least fourteen satellites to cover the Earth globally everyday using a LandSat-like sensor. Increasing the FOV three times reduces the need to four satellites, however adds image distortion and BRDF complexities to the observed reflectance. If narrow FOV sensors on a small satellite constellation were commanded using robust algorithms to slew their sensor dynamically, they would be able to coordinately cover the global landmass much faster without compensating for spatial resolution or BRDF effects. Our algorithm to optimize constellation satellite pointing is based on a dynamic programming approach under the constraints of orbital mechanics and existing attitude control systems for small satellites. As a case study for our algorithm, we minimize the time required to cover the 17000 Landsat images with maximum signal to noise ratio fall

  11. Realistic Covariance Prediction for the Earth Science Constellation

    NASA Technical Reports Server (NTRS)

    Duncan, Matthew; Long, Anne

    2006-01-01

    Routine satellite operations for the Earth Science Constellation (ESC) include collision risk assessment between members of the constellation and other orbiting space objects. One component of the risk assessment process is computing the collision probability between two space objects. The collision probability is computed using Monte Carlo techniques as well as by numerically integrating relative state probability density functions. Each algorithm takes as inputs state vector and state vector uncertainty information for both objects. The state vector uncertainty information is expressed in terms of a covariance matrix. The collision probability computation is only as good as the inputs. Therefore, to obtain a collision calculation that is a useful decision-making metric, realistic covariance matrices must be used as inputs to the calculation. This paper describes the process used by the NASA/Goddard Space Flight Center's Earth Science Mission Operations Project to generate realistic covariance predictions for three of the Earth Science Constellation satellites: Aqua, Aura and Terra.

  12. Risk to space sustainability from large constellations of satellites

    NASA Astrophysics Data System (ADS)

    Bastida Virgili, B.; Dolado, J. C.; Lewis, H. G.; Radtke, J.; Krag, H.; Revelin, B.; Cazaux, C.; Colombo, C.; Crowther, R.; Metz, M.

    2016-09-01

    The number of artificial objects in orbit continues to increase and, with it, a key threat to space sustainability. In response, space agencies have identified a set of mitigation guidelines aimed at enabling space users to reduce the generation of space debris by, for example, limiting the orbital lifetime of their spacecraft and launcher stages after the end of their mission. Planned, large constellations of satellites in low Earth orbit (LEO), though addressing the lack of basic internet coverage in some world regions, may disrupt the sustainability of the space environment enabled by these mitigation practices. We analyse the response of the space object population to the introduction of a large constellation conforming to the post-mission disposal guideline with differing levels of success and with different disposal orbit options. The results show that a high success rate of post-mission disposal by constellation satellites is a key driver for space sustainability.

  13. Low Earth orbit constellations: Orbit control or not

    NASA Astrophysics Data System (ADS)

    Radzik, Jose; Maral, Gerard

    1993-01-01

    The aim of the study is to list the arguments for and against the adoption of orbit control. The first section is a semi-analytical calculation of the probability of visibility with minimum elevation angle of a single satellite, to be used for altitudes less than 2000 km. Section two evaluates the number of noncontrolled satellites needed to guarantee a given probability of visibility for the whole constellation. Section three gives a comparison between noncontrolled and controlled constellations in the case of very low altitudes (less than 800 km). The main problem is the effect of atmospheric drag which reduces significantly the coverage performance of the satellite at its end of life. Evaluating the semi-major-axis contraction and eccentricity evolution with time allows us to define the noncontrolled satellite constellations.

  14. Design and Implementation of Satellite Formations and Constellations

    NASA Technical Reports Server (NTRS)

    Folta, David; Newman, Lauri Kraft; Quinn, David

    1998-01-01

    The direction to develop small low cost spacecraft has led many scientists to recognize the advantage of flying spacecraft in constellations and formations to achieve the correlated instrument measurements formerly possible only by flying many instruments on a single large platform. Yet, constellations and formation flying impose additional complications on orbit selection and orbit maintenance, especially when each spacecraft has its own orbit or science requirements. The purpose of this paper is to develop an operational control method for maintenance of these missions. Examples will be taken from the Earth Observing-1 (EO-1) spacecraft that is part of the New Millennium Program (NMP) and from proposed Earth System Science Program Office (ESSPO) constellations. Results can be used to determine the appropriateness of constellations and formation flying for a particular case as well as the operational impacts. Applications to the ESSPO and NMP are highly considered in analysis and applications. After constellation and formation analysis is completed, implementation of a maneuver maintenance strategy becomes the driver. Advances in technology and automation by GSFC's Guidance, Navigation, and Control Center allow more of the burden of the orbit selection and maneuver maintenance to be automated and ultimately placed onboard the spacecraft, mitigating most of the associated operational concerns. This paper presents the GSFC closed-loop control method to fly in either constellations or formations through the use of an autonomous closed loop three-axis navigation control and innovative orbit maintenance support. Simulation results using AutoCon(Trademark) and FreeFlyer(Trademark) with various fidelity levels of modeling and algorithms are presented.

  15. Design and implementation of satellite formations and constellations

    NASA Technical Reports Server (NTRS)

    Folta, David; Newman, Lauri Kraft; Quinn, David

    1998-01-01

    The direction to develop small low cost spacecraft has led many scientists to recognize the advantage of flying spacecraft in constellations and formations to achieve the correlated instrument measurements formerly possible only by flying many instruments on a single large platform. Yet, constellations and formation flying impose additional complications on orbit selection and orbit maintenance, especially when each spacecraft has its own orbit or science requirements. The purpose of this paper is to develop an operational control method for maintenance of these missions. Examples will be taken from the Earth Observing-1 (EO-1) spacecraft that is part of the New Millennium Program (NMP) and from proposed Earth System Science Program Office (ESSPO) constellations. Results can be used to determine the appropriateness of constellations and formation flying for a particular case as well as the operational impacts. Applications to the ESSPO and NMP are highly considered in analysis and applications. After constellation and formation analysis is completed, implementation of a maneuver maintenance strategy becomes the driver. Advances in technology and automation by GSFC's Guidance, Navigation, and Control Center allow more of the burden of the orbit selection and maneuver maintenance to be automated and ultimately placed onboard the spacecraft, mitigating most of the associated operational concerns. This paper presents the GSFC closed-loop control method to fly in either constellations or formations through the use of an autonomous closed loop three-axis navigation control and innovative orbit maintenance support. Simulation results using AutoCon(TM) and FreeFlyer(TM) with various fidelity levels of modeling and algorithms are presented.

  16. Small Satellite Constellations: The Future for Operational Earth Observation

    NASA Technical Reports Server (NTRS)

    Stephens, J. Paul

    2007-01-01

    Nanosat, microsat and minisat are low-cost, rapid-response small-satellites built from advanced terrestrial technology. SSTL delivers the benefits of affordable access to space through low-cost, rapid response, small satellites designed and built with state-of-the-art COTS technologies by: a) reducing the cost of entry into space; b) Achieving more missions within fixed budgets; c) making constellations and formation flying financially viable; d) responding rapidly from initial concept to orbital operation; and e) bringing the latest industrial COTS component advances to space. Growth has been stimulated in constellations for high temporal revisit&persistent monitoring and military responsive space assets.

  17. Optimal Constellation Design for Satellite Based Augmentation System

    NASA Astrophysics Data System (ADS)

    Kawano, Isao

    Global Positioning System (GPS) is widely utilized in daily life, for instance car navigation. Wide Area Augmentation System (WAAS) and Local Area Augmentation System (LAAS) are proposed so as to provide GPS better navigation accuracy and integrity capability. Satellite Based Augmentation System (SBAS) is a kind of WAAS and Multi-functional Transportation Satellite (MTSAT) has been developed in Japan. To improve navigation accuracy most efficiently, augmentation satellites should be so placed that minimize Geometric Dilution of Precision (GDOP) of constellation. In this paper the result of optimal constellation design for SBAS is shown.

  18. Electric propulsion for constellation deployment and spacecraft maneuvering

    NASA Technical Reports Server (NTRS)

    Deininger, W. D.; Vondra, R. J.

    1988-01-01

    This paper outlines the near-term (1990s) advantages of electric propulsion for two SDI missions: (1) the launch of a constellation of spacecraft, and (2) continual spacecraft defensive maneuvering. Ammonia arcjet and Xe-ion electric propulsion systems are compared to advanced chemical propulsion for each of these missions. The number of launch vehicles required for constellation deployment can be reduced by up to a factor of 2 when electric propulsion upper stages are used in place of advanced upper stages. Electric propulsion can provide significant benefits when used for continuous defensive maneuvering by enabling a large reduction in the initial spacecraft mass.

  19. The CEOS Atmospheric Composition Constellation (ACC), an Integrated Observing System

    NASA Astrophysics Data System (ADS)

    Hilsenrath, E.; Langen, J.; Zehner, C.

    2008-05-01

    The Atmospheric Composition (AC) Constellation is one of four pilot projects initiated by the Committee for Earth Observations Systems (CEOS) to bring about technical/scientific cooperation among space agencies that meet the goals of GEO and comply with the CEOS member agencies national programs. The Constellation concept has been endorsed in the GEO Work Plan, 2007-2009. The AC Constellation goal is to collect and deliver data to develop and improve monitoring, assessment and predictive capabilities for changes in the ozone layer, air quality and climate forcing associated with changes in the environment. These data will support five of the nine GEO SBAs: Health, Energy, Climate, Hazards, and Ecosystems. At the present time ESA, EC, CSA, CNES, JAXA, DLR, NIVR, NASA, NOAA and Eumetsat are participating in the Constellation study, and have major assets in orbit including 17 instruments on seven platforms. One goal of the Constellation study is to identify missing capabilities that will result when the present orbiting research satellites missions end and those not included in the next generation operational missions. Missing observations include very accurate and high spatial resolution measurements needed to be to track trends in atmospheric composition and understand their relationship to climate change. The following are the top level objectives for the AC Constellation Concept Study: • Develop a virtual constellation of existing and upcoming missions using synergies among the instruments and identify missing capabilities. • Study advanced architecture with new space assets and varying orbits with expectations that new technology could also be brought forward to best meet user requirements • Data system interoperability to insure that data are useful, properly targeted, and easily accessible. To demonstrate that the Constellation concept can provide value added data products, the ACC has initiated the three projects that are being supported by the

  20. Characteristics of signals originating near the lithium-diffused N+ contact of high purity germanium p-type point contact detectors

    DOE PAGES

    Aguayo, E.; Amman, M.; Avignone, F. T.; ...

    2012-11-09

    A study of signals originating near the lithium-diffused n+ contact of p-type point contact (PPC) high purity germanium detectors (HPGe) is presented. The transition region between the active germanium and the fully dead layer of the n+ contact is examined. Energy depositions in this transition region are shown to result in partial charge collection. This provides a mechanism for events with a well defined energy to contribute to the continuum of the energy spectrum at lower energies. A novel technique to quantify the contribution from this source of background is introduced. Furthermore, experiments that operate germanium detectors with a verymore » low energy threshold may benefit from the methods presented herein.« less

  1. Characteristics of signals originating near the lithium-diffused N+ contact of high purity germanium p-type point contact detectors

    SciTech Connect

    Aguayo, E.; Amman, M.; Avignone, F. T.; Barabash, A. S.; Barton, P. J.; Beene, J. R.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Chan, Y. -D.; Christofferson, C. D.; Collar, J. I.; Combs, D. C.; Cooper, R. J.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Elliott, S. R.; Esterline, J.; Fast, J. E.; Fields, N.; Finnerty, P.; Fraenkle, F. M.; Galindo-Uribarri, A.; Gehman, V. M.; Giovanetti, G. K.; Green, M. P.; Guiseppe, V. E.; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, R.; Hoppe, E. W.; Horton, M.; Howard, S.; Howe, M. A.; Johnson, R. A.; Keeter, K. J.; Kidd, M. F.; Knecht, A.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Leviner, L. E.; Loach, J. C.; Looker, Q.; Luke, P. N.; MacMullin, S.; Marino, M. G.; Martin, R. D.; Merriman, J. H.; Miller, M. L.; Mizouni, L.; Nomachi, M.; Orrell, J. L.; Overman, N. R.; Perumpilly, G.; Phillips, D. G.; Poon, A. W. P.; Radford, D. C.; Rielage, K.; Robertson, R. G. H.; Ronquest, M. C.; Schubert, A. G.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Steele, D.; Strain, J.; Timkin, V.; Tornow, W.; Varner, R. L.; Vetter, K.; Vorren, K.; Wilkerson, J. F.; Yakushev, E.; Yaver, H.; Young, A. R.; Yu, C. -H.; Yumatov, V.

    2012-11-09

    A study of signals originating near the lithium-diffused n+ contact of p-type point contact (PPC) high purity germanium detectors (HPGe) is presented. The transition region between the active germanium and the fully dead layer of the n+ contact is examined. Energy depositions in this transition region are shown to result in partial charge collection. This provides a mechanism for events with a well defined energy to contribute to the continuum of the energy spectrum at lower energies. A novel technique to quantify the contribution from this source of background is introduced. Furthermore, experiments that operate germanium detectors with a very low energy threshold may benefit from the methods presented herein.

  2. Classifying neuronal subclasses of the cerebellum through constellation pharmacology.

    PubMed

    Curtice, Kigen J; Leavitt, Lee S; Chase, Kevin; Raghuraman, Shrinivasan; Horvath, Martin P; Olivera, Baldomero M; Teichert, Russell W

    2016-02-01

    A pressing need in neurobiology is the comprehensive identification and characterization of neuronal subclasses within the mammalian nervous system. To this end, we used constellation pharmacology as a method to interrogate the neuronal and glial subclasses of the mouse cerebellum individually and simultaneously. We then evaluated the data obtained from constellation-pharmacology experiments by cluster analysis to classify cells into neuronal and glial subclasses, based on their functional expression of glutamate, acetylcholine, and GABA receptors, among other ion channels. Conantokin peptides were used to identify N-methyl-d-aspartate (NMDA) receptor subtypes, which revealed that neurons of the young mouse cerebellum expressed NR2A and NR2B NMDA receptor subunits. Additional pharmacological tools disclosed differential expression of α-amino-3-hydroxy-5-methyl-4-isoxazloepropionic, nicotinic acetylcholine, and muscarinic acetylcholine receptors in different neuronal and glial subclasses. Certain cell subclasses correlated with known attributes of granule cells, and we combined constellation pharmacology with genetically labeled neurons to identify and characterize Purkinje cells. This study illustrates the utility of applying constellation pharmacology to classify neuronal and glial subclasses in specific anatomical regions of the brain.

  3. Video Games, Identity, and the Constellation of Information

    ERIC Educational Resources Information Center

    Martin, Crystle

    2012-01-01

    This article explores the identity of youth in relation to the information sources they choose in the constellation of information of video games, using the massively multiplayer online game "World of Warcraft" as an example. From this study, several identities are recognized that are combinations of the participants skill and level in the game,…

  4. Optimal design of the satellite constellation arrangement reconfiguration process

    NASA Astrophysics Data System (ADS)

    Fakoor, Mahdi; Bakhtiari, Majid; Soleymani, Mahshid

    2016-08-01

    In this article, a novel approach is introduced for the satellite constellation reconfiguration based on Lambert's theorem. Some critical problems are raised in reconfiguration phase, such as overall fuel cost minimization, collision avoidance between the satellites on the final orbital pattern, and necessary maneuvers for the satellites in order to be deployed in the desired position on the target constellation. To implement the reconfiguration phase of the satellite constellation arrangement at minimal cost, the hybrid Invasive Weed Optimization/Particle Swarm Optimization (IWO/PSO) algorithm is used to design sub-optimal transfer orbits for the satellites existing in the constellation. Also, the dynamic model of the problem will be modeled in such a way that, optimal assignment of the satellites to the initial and target orbits and optimal orbital transfer are combined in one step. Finally, we claim that our presented idea i.e. coupled non-simultaneous flight of satellites from the initial orbital pattern will lead to minimal cost. The obtained results show that by employing the presented method, the cost of reconfiguration process is reduced obviously.

  5. Classifying neuronal subclasses of the cerebellum through constellation pharmacology

    PubMed Central

    Curtice, Kigen J.; Leavitt, Lee S.; Chase, Kevin; Raghuraman, Shrinivasan; Horvath, Martin P.; Olivera, Baldomero M.

    2015-01-01

    A pressing need in neurobiology is the comprehensive identification and characterization of neuronal subclasses within the mammalian nervous system. To this end, we used constellation pharmacology as a method to interrogate the neuronal and glial subclasses of the mouse cerebellum individually and simultaneously. We then evaluated the data obtained from constellation-pharmacology experiments by cluster analysis to classify cells into neuronal and glial subclasses, based on their functional expression of glutamate, acetylcholine, and GABA receptors, among other ion channels. Conantokin peptides were used to identify N-methyl-d-aspartate (NMDA) receptor subtypes, which revealed that neurons of the young mouse cerebellum expressed NR2A and NR2B NMDA receptor subunits. Additional pharmacological tools disclosed differential expression of α-amino-3-hydroxy-5-methyl-4-isoxazloepropionic, nicotinic acetylcholine, and muscarinic acetylcholine receptors in different neuronal and glial subclasses. Certain cell subclasses correlated with known attributes of granule cells, and we combined constellation pharmacology with genetically labeled neurons to identify and characterize Purkinje cells. This study illustrates the utility of applying constellation pharmacology to classify neuronal and glial subclasses in specific anatomical regions of the brain. PMID:26581874

  6. Key issues in constellation design optimization for NGSO satellite systems

    NASA Astrophysics Data System (ADS)

    Wang, Arthur W.

    1998-01-01

    This paper presents various constellation design criteria for satellite systems in non-geostationary orbits (NGSO). Key design parameters, constraints, and tradeoffs are discussed for two classes of orbits: circular and non-circular. Circular orbits, such as the low earth orbits (LEO), the medium earth orbits (MEO), and the highly inclined geosynchronous orbits (IGSO), have equal coverage period for both north and south hemispheres while non-circular orbits such as the various type of elliptical orbits provide more focused coverage period at certain specific geographic locations. Different services require various constraints including delay, power economics, coverage region, frequency sharing, total capacity, satellite and launch-vehicle numbers. Detailed discussion of the relationship between these constraints and constellations are provided. A comparison between a proposed benchmark MEO system with other proposed broadband NGSO satellite systems is presented to demonstrate the importance of constellation design to enhance frequency-sharing capability. A potential ``satellite highway'' accommodating families of elliptical geosynchronous satellites is also presented. This is a novel approach to regulatory NGSO constellations which will facilitate sharing valuable resources of spectrum and useful spatial areas.

  7. Constructing lightning towers for the Constellation Program and

    NASA Image and Video Library

    2007-11-09

    On Launch Pad 39B at NASA's Kennedy Space Center, workers measure the piling being pounded into the ground to help construct lightning towers for the Constellation Program and Ares/Orion launches. Pad B will be the site of the first Ares vehicle launch, including Ares I-X which is scheduled for April 2009.

  8. Constructing lightning towers for the Constellation Program and

    NASA Image and Video Library

    2007-11-09

    On Launch Pad 39B at NASA's Kennedy Space Center, pilings are being pounded into the ground to help construct lightning towers for the Constellation Program and Ares/Orion launches. Pad B will be the site of the first Ares vehicle launch, including Ares I-X which is scheduled for April 2009.

  9. Constructing lightning towers for the Constellation Program and

    NASA Image and Video Library

    2007-11-09

    On Launch Pad 39B at NASA's Kennedy Space Center, the crane crawler lifts a piling into place to be pounded into the ground to help construct lightning towers for the Constellation Program and Ares/Orion launches. Pad B will be the site of the first Ares vehicle launch, including Ares I-X which is scheduled for April 2009.

  10. Constructing lightning towers for the Constellation Program and

    NASA Image and Video Library

    2007-11-09

    On Launch Pad 39B at NASA's Kennedy Space Center, the crane crawler puts a piling into place to be pounded into the ground to help construct lightning towers for the Constellation Program and Ares/Orion launches. Pad B will be the site of the first Ares vehicle launch, including Ares I-X which is scheduled for April 2009.

  11. STS-54 astronomical observation of the constellation Orion

    NASA Image and Video Library

    1993-01-19

    STS054-97-018 (13-19 Jan 1993) --- The STS-54 crew used a handheld 70mm camera to record this view of the constellation Orion. Five astronauts spent six days aboard the Space Shuttle Endeavour in Earth orbit.

  12. Constructing lightning towers for the Constellation Program and

    NASA Image and Video Library

    2007-11-09

    On Launch Pad 39B at NASA's Kennedy Space Center, the crane crawler lifts a piling off a truck. The piling will be pounded into the ground to help construct lightning towers for the Constellation Program and Ares/Orion launches. Pad B will be the site of the first Ares vehicle launch, including Ares I-X which is scheduled for April 2009.

  13. Video Games, Identity, and the Constellation of Information

    ERIC Educational Resources Information Center

    Martin, Crystle

    2012-01-01

    This article explores the identity of youth in relation to the information sources they choose in the constellation of information of video games, using the massively multiplayer online game "World of Warcraft" as an example. From this study, several identities are recognized that are combinations of the participants skill and level in the game,…

  14. Launching Science: Science Opportunities Provided by NASA's Constellation System

    NASA Technical Reports Server (NTRS)

    2008-01-01

    In 2004 NASA began implementation of the first phases of a new space exploration policy. This implementation effort included the development of a new human-carrying spacecraft, known as Orion; the Altair lunar lander; and two new launch vehicles, the Ares I and Ares V rockets.collectively called the Constellation System (described in Chapter 5 of this report). The Altair lunar lander, which is in the very preliminary concept stage, is not discussed in detail in the report. In 2007 NASA asked the National Research Council (NRC) to evaluate the science opportunities enabled by the Constellation System. To do so, the NRC established the Committee on Science Opportunities Enabled by NASA's Constellation System. In general, the committee interpreted "Constellation-enabled" broadly, to include not only mission concepts that required Constellation, but also those that could be significantly enhanced by Constellation. The committee intends this report to be a general overview of the topic of science missions that might be enabled by Constellation, a sort of textbook introduction to the subject. The mission concepts that are reviewed in this report should serve as general examples of kinds of missions, and the committee s evaluation should not be construed as an endorsement of the specific teams that developed the mission concepts or of their proposals. Additionally, NASA has a well-developed process for establishing scientific priorities by asking the NRC to conduct a "decadal survey" for a particular discipline. Any scientific mission that eventually uses the Constellation System will have to be properly evaluated by means of this decadal survey process. The committee was impressed with the scientific potential of many of the proposals that it evaluated. However, the committee notes that the Constellation System has been justified by NASA and selected in order to enable human exploration beyond low Earth orbit.not to enable science missions. Virtually all of the science

  15. Launching Science: Science Opportunities Provided by NASA's Constellation System

    NASA Technical Reports Server (NTRS)

    2008-01-01

    In 2004 NASA began implementation of the first phases of a new space exploration policy. This implementation effort included the development of a new human-carrying spacecraft, known as Orion; the Altair lunar lander; and two new launch vehicles, the Ares I and Ares V rockets.collectively called the Constellation System (described in Chapter 5 of this report). The Altair lunar lander, which is in the very preliminary concept stage, is not discussed in detail in the report. In 2007 NASA asked the National Research Council (NRC) to evaluate the science opportunities enabled by the Constellation System. To do so, the NRC established the Committee on Science Opportunities Enabled by NASA's Constellation System. In general, the committee interpreted "Constellation-enabled" broadly, to include not only mission concepts that required Constellation, but also those that could be significantly enhanced by Constellation. The committee intends this report to be a general overview of the topic of science missions that might be enabled by Constellation, a sort of textbook introduction to the subject. The mission concepts that are reviewed in this report should serve as general examples of kinds of missions, and the committee s evaluation should not be construed as an endorsement of the specific teams that developed the mission concepts or of their proposals. Additionally, NASA has a well-developed process for establishing scientific priorities by asking the NRC to conduct a "decadal survey" for a particular discipline. Any scientific mission that eventually uses the Constellation System will have to be properly evaluated by means of this decadal survey process. The committee was impressed with the scientific potential of many of the proposals that it evaluated. However, the committee notes that the Constellation System has been justified by NASA and selected in order to enable human exploration beyond low Earth orbit.not to enable science missions. Virtually all of the science

  16. Constellation Program Life-cycle Cost Analysis Model (LCAM)

    NASA Technical Reports Server (NTRS)

    Prince, Andy; Rose, Heidi; Wood, James

    2008-01-01

    The Constellation Program (CxP) is NASA's effort to replace the Space Shuttle, return humans to the moon, and prepare for a human mission to Mars. The major elements of the Constellation Lunar sortie design reference mission architecture are shown. Unlike the Apollo Program of the 1960's, affordability is a major concern of United States policy makers and NASA management. To measure Constellation affordability, a total ownership cost life-cycle parametric cost estimating capability is required. This capability is being developed by the Constellation Systems Engineering and Integration (SE&I) Directorate, and is called the Lifecycle Cost Analysis Model (LCAM). The requirements for LCAM are based on the need to have a parametric estimating capability in order to do top-level program analysis, evaluate design alternatives, and explore options for future systems. By estimating the total cost of ownership within the context of the planned Constellation budget, LCAM can provide Program and NASA management with the cost data necessary to identify the most affordable alternatives. LCAM is also a key component of the Integrated Program Model (IPM), an SE&I developed capability that combines parametric sizing tools with cost, schedule, and risk models to perform program analysis. LCAM is used in the generation of cost estimates for system level trades and analyses. It draws upon the legacy of previous architecture level cost models, such as the Exploration Systems Mission Directorate (ESMD) Architecture Cost Model (ARCOM) developed for Simulation Based Acquisition (SBA), and ATLAS. LCAM is used to support requirements and design trade studies by calculating changes in cost relative to a baseline option cost. Estimated costs are generally low fidelity to accommodate available input data and available cost estimating relationships (CERs). LCAM is capable of interfacing with the Integrated Program Model to provide the cost estimating capability for that suite of tools.

  17. Human Systems Integration in Practice: Constellation Lessons Learned

    NASA Technical Reports Server (NTRS)

    Zumbado, Jennifer Rochlis

    2012-01-01

    NASA's Constellation program provided a unique testbed for Human Systems Integration (HSI) as a fundamental element of the Systems Engineering process. Constellation was the first major program to have HSI mandated by NASA's Human Rating document. Proper HSI is critical to the success of any project that relies on humans to function as operators, maintainers, or controllers of a system. HSI improves mission, system and human performance, significantly reduces lifecycle costs, lowers risk and minimizes re-design. Successful HSI begins with sufficient project schedule dedicated to the generation of human systems requirements, but is by no means solely a requirements management process. A top-down systems engineering process that recognizes throughout the organization, human factors as a technical discipline equal to traditional engineering disciplines with authority for the overall system. This partners with a bottoms-up mechanism for human-centered design and technical issue resolution. The Constellation Human Systems Integration Group (HSIG) was a part of the Systems Engineering and Integration (SE&I) organization within the program office, and existed alongside similar groups such as Flight Performance, Environments & Constraints, and Integrated Loads, Structures and Mechanisms. While the HSIG successfully managed, via influence leadership, a down-and-in Community of Practice to facilitate technical integration and issue resolution, it lacked parallel top-down authority to drive integrated design. This presentation will discuss how HSI was applied to Constellation, the lessons learned and best practices it revealed, and recommendations to future NASA program and project managers. This presentation will discuss how Human Systems Integration (HSI) was applied to NASA's Constellation program, the lessons learned and best practices it revealed, and recommendations to future NASA program and project managers on how to accomplish this critical function.

  18. Characterization of two neuronal subclasses through constellation pharmacology.

    PubMed

    Teichert, Russell W; Raghuraman, Shrinivasan; Memon, Tosifa; Cox, Jeffrey L; Foulkes, Tucker; Rivier, Jean E; Olivera, Baldomero M

    2012-07-31

    Different types of neurons diverge in function because they express their own unique set or constellation of signaling molecules, including receptors and ion channels that work in concert. We describe an approach to identify functionally divergent neurons within a large, heterogeneous neuronal population while simultaneously investigating specific isoforms of signaling molecules expressed in each. In this study we characterized two subclasses of menthol-sensitive neurons from cultures of dissociated mouse dorsal-root ganglia. Although these neurons represent a small fraction of the dorsal-root ganglia neuronal population, we were able to identify them and investigate the cell-specific constellations of ion channels and receptors functionally expressed in each subclass, using a panel of selective pharmacological tools. Differences were found in the functional expression of ATP receptors, TRPA1 channels, voltage-gated calcium-, potassium-, and sodium channels, and responses to physiologically relevant cold temperatures. Furthermore, the cell-specific responses to various stimuli could be altered through pharmacological interventions targeted to the cell-specific constellation of ion channels expressed in each menthol-sensitive subclass. In fact, the normal responses to cold temperature could be reversed in the two neuronal subclasses by the coapplication of the appropriate combination of pharmacological agents. This result suggests that the functionally integrated constellation of signaling molecules in a particular type of cell is a more appropriate target for effective pharmacological intervention than a single signaling molecule. This shift from molecular to cellular targets has important implications for basic research and drug discovery. We refer to this paradigm as "constellation pharmacology."

  19. CubeSat constellation design for air traffic monitoring

    NASA Astrophysics Data System (ADS)

    Nag, Sreeja; Rios, Joseph L.; Gerhardt, David; Pham, Camvu

    2016-11-01

    Suitably equipped global and local air traffic can be tracked. The tracking information may then be used for control from ground-based stations by receiving the Automatic Dependent Surveillance-Broadcast (ADS-B) signal. In this paper, we describe a tool for designing a constellation of small satellites which demonstrates, through high-fidelity modeling based on simulated air traffic data, the value of space-based ADS-B monitoring. It thereby provides recommendations for cost-efficient deployment of a constellation of small satellites to increase safety and situational awareness in the currently poorly-served surveillance area of Alaska. Air traffic data were obtained from NASA's Future ATM Concepts Evaluation Tool, for the Alaskan airspace over one day. The results presented were driven by MATLAB and the satellites propagated and coverage calculated using AGI's Satellite Tool. While Ad-hoc and precession spread constellations have been quantitatively evaluated, Walker constellations show the best performance in simulation. Sixteen satellites in two perpendicular orbital planes are shown to provide more than 99% coverage over representative Alaskan airspace and the maximum time gap where any airplane in Alaska is not covered is six minutes, therefore meeting the standard set by the International Civil Aviation Organization to monitor every airplane at least once every fifteen minutes. In spite of the risk of signal collision when multiple packets arrive at the satellite receiver, the proposed constellation shows 99% cumulative probability of reception within four minutes when the airplanes are transmitting every minute, and at 100% reception probability if transmitting every second. Data downlink can be performed using any of the three ground stations of NASA Earth Network in Alaska.

  20. The NASA EV-2 CYGNSS Small Satellite Constellation Mission

    NASA Astrophysics Data System (ADS)

    Ruf, C. S.; Gleason, S.; Jelenak, Z.; Katzberg, S. J.; Ridley, A. J.; Rose, R.; Scherrer, J.; Zavorotny, V.

    2012-12-01

    The NASA EV-2 Cyclone Global Navigation Satellite System (CYGNSS) is a spaceborne mission focused on tropical cyclone (TC) inner core process studies. CYGNSS attempts to resolve the principle deficiencies with current TC intensity forecasts, which lies in inadequate observations and modeling of the inner core. The inadequacy in observations results from two causes: 1) Much of the inner core ocean surface is obscured from conventional remote sensing instruments by intense precipitation in the eye wall and inner rain bands. 2) The rapidly evolving (genesis and intensification) stages of the TC life cycle are poorly sampled in time by conventional polar-orbiting, wide-swath surface wind imagers. CYGNSS is specifically designed to address these two limitations by combining the all-weather performance of GNSS bistatic ocean surface scatterometry with the sampling properties of a constellation of satellites. The use of a dense constellation of nanosatellite results in spatial and temporal sampling properties that are markedly different from conventional imagers. Simulation studies will be presented which examine the sampling as functions of various orbit parameters of the constellation. Historical records of actual TC storm tracks are overlaid onto a simulated time series of the surface wind sampling enabled by the constellation. For comparison purposes, a similar analysis is conducted using the sampling properties of several past and present conventional spaceborne ocean wind scatterometers. Differences in the ability of the sensors to resolve the evolution of the TC inner core are examined. The spacecraft and constellation mission are described. The signal-to-noise ratio of the measured scattered signal and the resulting uncertainty in retrieved surface wind speed are also examined.

  1. Characterization of two neuronal subclasses through constellation pharmacology

    PubMed Central

    Teichert, Russell W.; Raghuraman, Shrinivasan; Memon, Tosifa; Cox, Jeffrey L.; Foulkes, Tucker; Rivier, Jean E.; Olivera, Baldomero M.

    2012-01-01

    Different types of neurons diverge in function because they express their own unique set or constellation of signaling molecules, including receptors and ion channels that work in concert. We describe an approach to identify functionally divergent neurons within a large, heterogeneous neuronal population while simultaneously investigating specific isoforms of signaling molecules expressed in each. In this study we characterized two subclasses of menthol-sensitive neurons from cultures of dissociated mouse dorsal-root ganglia. Although these neurons represent a small fraction of the dorsal-root ganglia neuronal population, we were able to identify them and investigate the cell-specific constellations of ion channels and receptors functionally expressed in each subclass, using a panel of selective pharmacological tools. Differences were found in the functional expression of ATP receptors, TRPA1 channels, voltage-gated calcium-, potassium-, and sodium channels, and responses to physiologically relevant cold temperatures. Furthermore, the cell-specific responses to various stimuli could be altered through pharmacological interventions targeted to the cell-specific constellation of ion channels expressed in each menthol-sensitive subclass. In fact, the normal responses to cold temperature could be reversed in the two neuronal subclasses by the coapplication of the appropriate combination of pharmacological agents. This result suggests that the functionally integrated constellation of signaling molecules in a particular type of cell is a more appropriate target for effective pharmacological intervention than a single signaling molecule. This shift from molecular to cellular targets has important implications for basic research and drug discovery. We refer to this paradigm as “constellation pharmacology.” PMID:22778416

  2. 76 FR 66054 - Exelon Corporation Constellation Energy Group, Inc.; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-25

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Exelon Corporation Constellation Energy Group, Inc.; Notice of Filing Take notice that, on October 11, 2011, Exelon Corporation and Constellation Energy Group, Inc....

  3. 75 FR 53688 - Constellation Mystic Power, LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-01

    ...-000] Constellation Mystic Power, LLC; Supplemental Notice That Initial Market-Based Rate Filing... the above-referenced proceeding of Constellation Mystic Power, LLC's application for market-based...

  4. 78 FR 30295 - Constellation Energy Commoditiesgroup, Inc., ENI USA Gas Marketing LLC, Sequent Energy Canada...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-22

    ..., and 13-32-LNG] Constellation Energy Commoditiesgroup, Inc., ENI USA Gas Marketing LLC, Sequent Energy........... Constellation Order vacating blanket Energy authority to import/export Commodities natural gas from/to...

  5. Vernal Point and Anthropocene

    NASA Astrophysics Data System (ADS)

    Chavez-Campos, Teodosio; Chavez S, Nadia; Chavez-Sumarriva, Israel

    2014-05-01

    The time scale was based on the internationally recognized formal chronostratigraphical /geochronological subdivisions of time: The Phanerozoic Eonathem/Eon; the Cenozoic Erathem/Era; the Quaternary System/Period; the Pleistocene and Holocene Series/Epoch. The Quaternary was divided into: (1) The Pleistocene that was characterized by cycles of glaciations (intervals between 40,000 and 100,000 years). (2) The Holocene that was an interglacial period that began about 12,000 years ago. It was believed that the Milankovitch cycles (eccentricity, axial tilt and the precession of the equinoxes) were responsible for the glacial and interglacial Holocene periods. The magnetostratigraphic units have been widely used for global correlations valid for Quaternary. The gravitational influence of the sun and moon on the equatorial bulges of the mantle of the rotating earth causes the precession of the earth. The retrograde motion of the vernal point through the zodiacal band is 26,000 years. The Vernal point passes through each constellation in an average of 2000 years and this period of time was correlated to Bond events that were North Atlantic climate fluctuations occurring every ≡1,470 ± 500 years throughout the Holocene. The vernal point retrogrades one precessional degree approximately in 72 years (Gleissberg-cycle) and approximately enters into the Aquarius constellation on March 20, 1940. On earth this entry was verify through: a) stability of the magnetic equator in the south central zone of Peru and in the north zone of Bolivia, b) the greater intensity of equatorial electrojet (EEJ) in Peru and Bolivia since 1940. With the completion of the Holocene and the beginning of the Anthropocene (widely popularized by Paul Crutzen) it was proposed the date of March 20, 1940 as the beginning of the Anthropocene. The date proposed was correlated to the work presented in IUGG (Italy 2007) with the title "Cusco base meridian for the study of geophysical data"; Cusco was

  6. Leonardo-BRDF: A New Generation Satellite Constellation

    NASA Technical Reports Server (NTRS)

    Esper, Jaime; Neeck, Steven; Wiscombe, Warren; Ryschkewitsch, Michael; Andary, J. (Technical Monitor)

    2000-01-01

    Instantaneous net radiation flux at the top of the atmosphere is one of the primary drivers of climate and global change. Since the dawn of the satellite era, great efforts and expense have gone into measuring this flux from single satellites and even (for a several-year period) from a constellation of three satellites called ERBE. However, the reflected solar flux is an angular and spectral integral over the so-called "BRDF" or Bidirectional Reflectance Distribution Function, which is the angular distribution of reflected solar radiation for each solar zenith angle and each wavelength. Previous radiation flux satellites could not measure instantaneous BRDF, so scientists have had to fall back on models or composites. Because their range of observed solar zenith angles was very limited due to sunsynchronous orbits, the resultant flux maps are too inaccurate to see the dynamics of radiation flux or to reliably correlate it with specific phenomena (hurricanes, biomass fires, urban pollution, dust outbreaks, etc.). Accuracy only becomes acceptable after monthly averaging, but this washes out almost all cause-and-effect information, further exacerbated by the lack of spectral resolution. Leonardo-BRDF is a satellite system designed to measure the instantaneous spectral BRDF using a formation of highly coordinated satellites, all pointing at the same Earth targets at the same time. It will allow scientists for the first time to assess the radiative forcing of climate due to specific phenomena, which is bound to be important in the ongoing debate about global warming and what is causing it. The formation is composed of two satellite types having, as instrument payloads, single highly-integrated miniature imaging spectrometers or radiometers. Two nearby "keystone" satellites anchor the formation and fly in static orbits. They employ wide field of view imaging spectrometers that are extremely light and compact. The keystone satellites are identical and can operate in

  7. Landmark constellation models for medical image content identification and localization.

    PubMed

    Hansis, Eberhard; Lorenz, Cristian

    2016-07-01

    Many medical imaging tasks require the detection and localization of anatomical landmarks, for example for the initialization of model-based segmentation or to detect anatomical regions present in an image. A large number of landmark and object localization methods have been described in the literature. The detection of single landmarks may be insufficient to achieve robust localization across a variety of imaging settings and subjects. Furthermore, methods like the generalized Hough transform yield the most likely location of an object, but not an indication whether or not the landmark was actually present in the image. For these reasons, we developed a simple and computationally efficient method combining localization results from multiple landmarks to achieve robust localization and to compute a localization confidence measure. For each anatomical region, we train a constellation model indicating the mean relative locations and location variability of a set of landmarks. This model is registered to the landmarks detected in a test image via point-based registration, using closed-form solutions. Three different outlier suppression schemes are compared, two using iterative re-weighting based on the residual landmark registration errors and the third being a variant of RANSAC. The mean weighted residual registration error serves as a confidence measure to distinguish true from false localization results. The method is optimized and evaluated on synthetic data, evaluating both the localization accuracy and the ability to classify good from bad registration results based on the residual registration error. Two application examples are presented: the identification of the imaged anatomical region in trauma CT scans and the initialization of model-based segmentation for C-arm CT scans with different target regions. The identification of the target region with the presented method was in 96 % of the cases correct. The presented method is a simple solution for combining

  8. Exploring the Architectural Tradespace of Severe Weather Monitoring Nanosatellite Constellations

    NASA Astrophysics Data System (ADS)

    Hitomi, N.; Selva, D.; Blackwell, W. J.

    2014-12-01

    MicroMAS-1, a 3U nanosatellite developed by MIT/LL, MIT/SSL, and University of Massachusetts, was launched on July 13, 2014 and is scheduled for deployment from the International Space Station in September. The development of MicroMAS motivates an architectural analysis of a constellation of nanosatellites with the goal of drastically reducing the cost of observing severe storms compared with current monolithic missions such as the Precision and All-Weather Temperature and Humidity (PATH) mission from the NASA Decadal Survey. Our goal is to evolve the instrument capability on weather monitoring nanosatellites to achieve higher performance and better satisfy stakeholder needs. Clear definitions of performance requirements are critical in the conceptual design phase when much of the project's lifecycle cost and performance will be fixed. Ability to perform trade studies and optimization of performance needs with instrument capability will enable design teams to focus on key technologies that will introduce high value and high return on investment. In this work, we approach the significant trades and trends of constellations for monitoring severe storms by applying our rule-based decision support tool. We examine a subset of stakeholder groups listed in the OSCAR online database (e.g., weather, climate) that would benefit from severe storm weather data and their respective observation requirements (e.g. spatial resolution, accuracy). We use ten parameters in our analysis, including atmospheric temperature, humidity, and precipitation. We compare the performance and cost of thousands of different possible constellations. The constellations support hyperspectral sounders that cover different portions of the millimeter-wave spectrum (50-60 GHz, 118GHz, 183GHz) in different orbits, and the performance results are compared against those of the monolithic PATH mission. Our preliminary results indicate that constellations using the hyperspectral millimeter wave sounders can

  9. Phase Compensation Sensor for Ranging Consistency in Inter-Satellite Links of Navigation Constellation.

    PubMed

    Meng, Zhijun; Yang, Jun; Guo, Xiye; Hu, Mei

    2017-02-24

    Theperformanceoftheglobalnavigationsatellitesystem(GNSS)canbeenhancedsignificantly by introducing the inter-satellite links (ISL) of a navigation constellation. In particular, the improvement of the position, velocity, and time accuracy, and the realization of autonomous functions require the ISL distance measurement data as the original input. For building a high-performance ISL, the ranging consistency between navigation satellites becomes a crucial problem to be addressed. Considering the frequency aging drift and the relativistic effect of the navigation satellite, the frequency and phase adjustment (FPA) instructions for the 10.23 MHz must be injected from the ground station to ensure the time synchronization of the navigation constellation. Moreover, the uncertainty of the initial phase each time the onboard clock equipment boots also results in a pseudo-range offset. In this Ref., we focus on the influence of the frequency and phase characteristics of the onboard clock equipment on the ranging consistency of the ISL and propose a phase compensation sensor design method for the phase offset. The simulation and experimental results show that the proposed method not only realized a phase compensation for the pseudo-range jitter, but, when the 1 PPS (1 pulse per second) falls in the 10.23 MHz skip area, also overcomes the problem of compensating the ambiguous phase by directly tracking the 10.23 MHz to ensure consistency in the ranging.

  10. Phase Compensation Sensor for Ranging Consistency in Inter-Satellite Links of Navigation Constellation

    PubMed Central

    Meng, Zhijun; Yang, Jun; Guo, Xiye; Hu, Mei

    2017-01-01

    The performance of the global navigation satellite system (GNSS) can be enhanced significantly by introducing the inter-satellite links (ISL) of a navigation constellation. In particular, the improvement of the position, velocity, and time accuracy, and the realization of autonomous functions require the ISL distance measurement data as the original input. For building a high-performance ISL, the ranging consistency between navigation satellites becomes a crucial problem to be addressed. Considering the frequency aging drift and the relativistic effect of the navigation satellite, the frequency and phase adjustment (FPA) instructions for the 10.23 MHz must be injected from the ground station to ensure the time synchronization of the navigation constellation. Moreover, the uncertainty of the initial phase each time the onboard clock equipment boots also results in a pseudo-range offset. In this Ref., we focus on the influence of the frequency and phase characteristics of the onboard clock equipment on the ranging consistency of the ISL and propose a phase compensation sensor design method for the phase offset. The simulation and experimental results show that the proposed method not only realized a phase compensation for the pseudo-range jitter, but, when the 1 PPS (1 pulse per second) falls in the 10.23 MHz skip area, also overcomes the problem of compensating the ambiguous phase by directly tracking the 10.23 MHz to ensure consistency in the ranging. PMID:28245572

  11. Optimization of regional navigation satellite constellation by improved NSGA-II algorithm

    NASA Astrophysics Data System (ADS)

    Chang, Hui; Hu, Xiulin; Zhang, Yunyu; Zeng, Yujiang; Wang, Ying

    2009-12-01

    In this paper, the non-dominated sorting genetic algorithm II (NSGA-II) based on the concept of Pareto optimal is improved. A new algorithm with lower O(MNlogN) computational complexity to construct non-dominated set replaces the NSGA-II original fast non-dominated sorting algorithm with O(MN2) com-putational complexity. The new algorithm improves operating efficiency of NSGA-II significantly. Based on the combination of the improved NSGA-II algorithm and regional navigation satellite constellation design, a new idea to design regional navigation satellite constellation is proposed in this paper. The new idea is implemented by Satellite Tool Kits (STK) and Matlab: the improved NSGA-II algorithm is implemented by Matlab and the calculation of the objective function values is implemented by STK. STK/Connect interface is used to integrate STK and Matlab into one simulation. Simulation results show that new idea has some advantages over the traditional methods, being more efficient, more flexible and more comprehensive.

  12. Investigate the Upflow Ions with a Constellation: An introduction to a Future Chinese Mission

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Wang, C.; Xu, J.; Klecker, B.

    2014-12-01

    The ions upflowing from the ionosphere into the magnetosphere are vital for the coupling of Earth's magnetosphere and ionosphere because they play a very important role in the initiation and development of the geospace storm caused by solar disturbance.The Magnetosphere-Ionosphere-Thermosphere Coupling Small-Satellite Constellation Mission (MIT) is a Chinese mission targeting at the coupling processes of the earth's magnetosphere-ionosphere-thermosphere system. The mission's science objectives focus on the acceleration mechanism and the origin of outflow ions and other related outstanding scientific questions. The mission plans a constellation composed of four satellites orbiting the earth at three different altitudes. The proposed payloads include particles detectors, field detectors, aurora and neutral imaging system. These payloads will measure the plasma compositions and the electromagnetic waves, therefore determine the key acceleration mechanisms for the oxygen ions. This mission is selected as a background model supported by the strategy pioneer program of Chinese Academy of Science. The proposed lunch date is between 2019 to 2020.

  13. Acquisition through horizontal gene transfer of plasmid pSMA198 by Streptococcus macedonicus ACA-DC 198 points towards the dairy origin of the species.

    PubMed

    Papadimitriou, Konstantinos; Anastasiou, Rania; Maistrou, Eleni; Plakas, Thomas; Papandreou, Nikos C; Hamodrakas, Stavros J; Ferreira, Stéphanie; Supply, Philip; Renault, Pierre; Pot, Bruno; Tsakalidou, Effie

    2015-01-01

    Streptococcus macedonicus is an intriguing streptococcal species whose most frequent source of isolation is fermented foods similarly to Streptococcus thermophilus. However, S. macedonicus is closely related to commensal opportunistic pathogens of the Streptococcus bovis/Streptococcus equinus complex. We analyzed the pSMA198 plasmid isolated from the dairy strain Streptococcus macedonicus ACA-DC 198 in order to provide novel clues about the main ecological niche of this bacterium. pSMA198 belongs to the narrow host range pCI305/pWV02 family found primarily in lactococci and to the best of our knowledge it is the first such plasmid to be reported in streptococci. Comparative analysis of the pSMA198 sequence revealed a high degree of similarity with plasmids isolated from Lactococcus lactis strains deriving from milk or its products. Phylogenetic analysis of the pSMA198 Rep showed that the vast majority of closely related proteins derive from lactococcal dairy isolates. Additionally, cloning of the pSMA198 ori in L. lactis revealed a 100% stability of replication over 100 generations. Both pSMA198 and the chromosome of S. macedonicus exhibit a high percentage of potential pseudogenes, indicating that they have co-evolved under the same gene decay processes. We identified chromosomal regions in S. macedonicus that may have originated from pSMA198, also supporting a long co-existence of the two replicons. pSMA198 was also found in divergent biotypes of S. macedonicus and in strains isolated from dispersed geographic locations (e.g. Greece and Switzerland) showing that pSMA198's acquisition is not a recent event. Here we propose that S. macedonicus acquired plasmid pSMA198 from L. lactis via an ancestral genetic exchange event that took place most probably in milk or dairy products. We provide important evidence that point towards the dairy origin of this species.

  14. Fundamentals of the route theory for satellite constellation design for Earth discontinuous coverage. Part 2: Synthesis of satellite orbits and constellations

    NASA Astrophysics Data System (ADS)

    Razoumny, Yury N.

    2016-11-01

    The method for synthesis of satellite orbits and constellations, optimized by given criterion (minimum of required number of satellites in the constellation, or minimum revisit time, or minimum of the satellites' swath width required) for fixed parameters of on-board satellite equipment and constraints for unused criterion parameters of a list of mentioned above is presented. The numerical results demonstrate the possibilities of the method developed basing on analyzing the given satellite constellation revisit time values distributed on the Earth coverage area, and for synthesizing the satellite constellations to minimize revisit time in comparison with the traditional approaches based on constellation design in a priori fixed classes used for continuous coverage. Particularly, it is shown that the suggested synthesis method, basing on the simplest type of Route Constellations considered - Secure Route Constellations, directly leads, as result of high speed calculations for given Earth region coverage (seconds, or minutes as a worst case), to the optimized satellite constellations which provide consistently high performance and are better, or at least on the same level, in comparison with the best Walker constellations for discontinuous coverage. In order to have comprehensive coverage picture, both deterministic, and stochastic approaches are considered for estimation of the coverage characteristics of the given region of arbitrary shape, basing on the results of Earth coverage analytic emulation.

  15. RaInCube: a proposed constellation of precipitation profiling Radars In Cubesat

    NASA Astrophysics Data System (ADS)

    Peral, E.; Tanelli, S.; Haddad, Z. S.; Stephens, G. L.; Im, E.

    2014-12-01

    Precipitation radars in Low-Earth-Orbit provide vertically resolved profiles of rain and snow on a global scale. With the recent advances in miniaturized radar and CubeSat/SmallSat technologies, it would now be feasible to launch multiple copies of the same radar instrument in desirable formations to allow measurements of short time scale evolution of atmospheric processes. One such concept is the novel radar architecture compatible with the 6U CubeSat class that is being developed at JPL by exploiting simplification and miniaturization of the radar subsystems. The RaInCube architecture would significantly reduce the number of components, power consumption and mass with respect to existing spaceborne radars. The baseline RaInCube instrument configuration would be a fixed nadir-pointing profiler at Ka-band with a minimum detectable reflectivity better than +10 dBZ at 250m range resolution and 5 km horizontal resolution. The low cost nature of the RaInCube platform would enable deployment of a constellation of identical copies of the same instrument in various relative positions in LEO to address specific observational gaps left open by the current missions that require high-resolution vertical profiling capability. A constellation of only four RaInCubes would populate the precipitation statistics in a distributed fashion across the globe and across the times of day, and therefore, would enable substantially better sampling of the diurnal cycle statistics. One could extend this scheme by adding more RaInCubes in each of the orbital planes, and phase them once in orbit so that they would be separated by an arbitrary amount of time among them. Wide separations (say 20-30 min) would further extend the sampling of the diurnal cycle to sub-hourly scales. Narrower time separations between RaInCubes would allow studying the evolution of convective systems at the convective time scale in each region of interest and would reveal the dominant modes of evolution of each

  16. A point mutation in the polymerase protein PB2 allows a reassortant H9N2 influenza isolate of wild-bird origin to replicate in human cells.

    PubMed

    Hussein, Islam T M; Ma, Eric J; Hill, Nichola J; Meixell, Brandt W; Lindberg, Mark; Albrecht, Randy A; Bahl, Justin; Runstadler, Jonathan A

    2016-07-01

    H9N2 influenza A viruses are on the list of potentially pandemic subtypes. Therefore, it is important to understand how genomic reassortment and genetic polymorphisms affect phenotypes of H9N2 viruses circulating in the wild bird reservoir. A comparative genetic analysis of North American H9N2 isolates of wild bird origin identified a naturally occurring reassortant virus containing gene segments derived from both North American and Eurasian lineage ancestors. The PB2 segment of this virus encodes 10 amino acid changes that distinguish it from other H9 strains circulating in North America. G590S, one of the 10 amino acid substitutions observed, was present in ~12% of H9 viruses worldwide. This mutation combined with R591 has been reported as a marker of pathogenicity for human pandemic 2009 H1N1 viruses. Screening by polymerase reporter assay of all the natural polymorphisms at these two positions identified G590/K591 and S590/K591 as the most active, with the highest polymerase activity recorded for the SK polymorphism. Rescued viruses containing these two polymorphic combinations replicated more efficiently in MDCK cells and they were the only ones tested that were capable of establishing productive infection in NHBE cells. A global analysis of all PB2 sequences identified the K591 signature in six viral HA/NA subtypes isolated from several hosts in seven geographic locations. Interestingly, introducing the K591 mutation into the PB2 of a human-adapted H3N2 virus did not affect its polymerase activity. Our findings demonstrate that a single point mutation in the PB2 of a low pathogenic H9N2 isolate could have a significant effect on viral phenotype and increase its propensity to infect mammals. However, this effect is not universal, warranting caution in interpreting point mutations without considering protein sequence context.

  17. A point mutation in the polymerase protein PB2 allows a reassortant H9N2 influenza isolate of wild-bird origin to replicate in human cells

    PubMed Central

    Hussein, Islam T. M.; Ma, Eric J.; Hill, Nichola J.; Meixell, Brandt W.; Lindberg, Mark; Albrecht, Randy A.; Bahl, Justin; Runstadler, Jonathan A.

    2016-01-01

    H9N2 influenza A viruses are on the list of potentially pandemic subtypes. Therefore, it is important to understand how genomic reassortment and genetic polymorphisms affect phenotypes of H9N2 viruses circulating in the wild bird reservoir. A comparative genetic analysis of North American H9N2 isolates of wild bird origin identified a naturally occurring reassortant virus containing gene segments derived from both North American and Eurasian lineage ancestors. The PB2 segment of this virus encodes 10 amino acid changes that distinguish it from other H9 strains circulating in North America. G590S, one of the 10 amino acid substitutions observed, was present in ∼12% of H9 viruses worldwide. This mutation combined with R591 has been reported as a marker of pathogenicity for human pandemic 2009 H1N1 viruses. Screening by polymerase reporter assay of all the natural polymorphisms at these two positions identified G590/K591 and S590/K591 as the most active, with the highest polymerase activity recorded for the SK polymorphism. Rescued viruses containing these two polymorphic combinations replicated more efficiently in MDCK cells and they were the only ones tested that were capable of establishing productive infection in NHBE cells. A global analysis of all PB2 sequences identified the K591 signature in six viral HA/NA subtypes isolated from several hosts in seven geographic locations. Interestingly, introducing the K591 mutation into the PB2 of a human-adapted H3N2 virus did not affect its polymerase activity. Our findings demonstrate that a single point mutation in the PB2 of a low pathogenic H9N2 isolate could have a significant effect on viral phenotype and increase its propensity to infect mammals. However, this effect is not universal, warranting caution in interpreting point mutations without considering protein sequence context. PMID:27101787

  18. A point mutation in the polymerase protein PB2 allows a reassortant H9N2 influenza isolate of wild-bird origin to replicate in human cells.

    USGS Publications Warehouse

    Hussein, Islam T.M.; Ma, Eric J.; Meixell, Brandt; Hill, Nichola J.; Lindberg, Mark S.; Albrecht , Randy A.; Bahl, Justin; Runstadler, Jonathan A.

    2016-01-01

    H9N2 influenza A viruses are on the list of potentially pandemic subtypes. Therefore, it is important to understand how genomic reassortment and genetic polymorphisms affect phenotypes of H9N2 viruses circulating in the wild bird reservoir. A comparative genetic analysis of North American H9N2 isolates of wild bird origin identified a naturally occurring reassortant virus containing gene segments derived from both North American and Eurasian lineage ancestors. The PB2 segment of this virus encodes 10 amino acid changes that distinguish it from other H9 strains circulating in North America. G590S, one of the 10 amino acid substitutions observed, was present in ~ 12% of H9 viruses worldwide. This mutation combined with R591 has been reported as a marker of pathogenicity for human pandemic 2009 H1N1 viruses. Screening by polymerase reporter assay of all the natural polymorphisms at these two positions identified G590/K591 and S590/K591 as the most active, with the highest polymerase activity recorded for the SK polymorphism. Rescued viruses containing these two polymorphic combinations replicated more efficiently in MDCK cells and they were the only ones tested that were capable of establishing productive infection in NHBE cells. A global analysis of all PB2 sequences identified the K591 signature in six viral HA/NA subtypes isolated from several hosts in seven geographic locations. Interestingly, introducing the K591 mutation into the PB2 of a human-adapted H3N2 virus did not affect its polymerase activity. Our findings demonstrate that a single point mutation in the PB2 of a low pathogenic H9N2 isolate could have a significant effect on viral phenotype and increase its propensity to infect mammals. However, this effect is not universal, warranting caution in interpreting point mutations without considering protein sequence context.

  19. Enhancements to TetrUSS for NASA Constellation Program

    NASA Technical Reports Server (NTRS)

    Pandya, Mohagna J.; Frink, Neal T.; Abdol-Hamid, Khaled S.; Samareh, Jamshid A,; Parlete, Edward B.; Taft, James R.

    2011-01-01

    The NASA Constellation program is utilizing Computational Fluid Dynamics (CFD) predictions for generating aerodynamic databases and design loads for the Ares I, Ares I-X, and Ares V launch vehicles and for aerodynamic databases for the Orion crew exploration vehicle and its launch abort system configuration. This effort presents several challenges to applied aerodynamicists due to complex geometries and flow physics, as well as from the juxtaposition of short schedule program requirements with high fidelity CFD simulations. NASA TetrUSS codes (GridTool/VGRID/USM3D) have been making extensive contributions in this effort. This paper will provide an overview of several enhancements made to the various elements of TetrUSS suite of codes. Representative TetrUSS solutions for selected Constellation program elements will be shown. Best practices guidelines and scripting developed for generating TetrUSS solutions in a production environment will also be described.

  20. Science with Constellation-X, Choice of Instrumentation

    NASA Technical Reports Server (NTRS)

    Hornscheimeier, Ann; White, Nicholas; Tananbaum, Harvey; Garcia, Michael; Bookbinder, Jay; Petre, Robert; Cottam, Jean

    2007-01-01

    The Constellation X-ray Observatory is one of the two Beyond Einstein Great Observatories and will provide a 100-fold increase in collecting area in high spectral resolving power X-ray instruments over the Chandra and XMM-Newton gratings instruments. The mission has four main science objectives which drive the requirements for the mission. This contribution to the Garmire celebration conference describes these four science areas: Black Holes, Dark Energy, Missing Baryons, and the Neutron Star Equation of State as well as the requirements flow-down that give rise to the choice of instrumentation and implementation for Constellation-X. As we show, each of these science areas place complementary constraints on mission performance parameters such as collecting area, spectral resolving power, timing resolution, and field of view. The mission's capabilities will enable a great breadth of science, and its resources will be open to the community through its General Observer program.

  1. Realistic Covariance Prediction For the Earth Science Constellations

    NASA Technical Reports Server (NTRS)

    Duncan, Matthew; Long, Anne

    2006-01-01

    Routine satellite operations for the Earth Science Constellations (ESC) include collision risk assessment between members of the constellations and other orbiting space objects. One component of the risk assessment process is computing the collision probability between two space objects. The collision probability is computed via Monte Carlo techniques as well as numerically integrating relative probability density functions. Each algorithm takes as inputs state vector and state vector uncertainty information for both objects. The state vector uncertainty information is expressed in terms of a covariance matrix. The collision probability computation is only as good as the inputs. Therefore, to obtain a collision calculation that is a useful decision-making metric, realistic covariance matrices must be used as inputs to the calculation. This paper describes the process used by NASA Goddard's Earth Science Mission Operations Project to generate realistic covariance predictions for three of the ESC satellites: Aqua, Aura, and Terra

  2. Global Observations from a Constellation of Small Satellites

    NASA Astrophysics Data System (ADS)

    Bailey, S. M.; Allen, D. R.; Bevilacqua, R. M.; Fish, C. S.; Fromm, M. D.; Gordley, L. L.; Hoppel, K.; Marshall, B. T.; McHugh, M. J.; Nedoluha, G. E.

    2011-12-01

    The emergence of reliable, miniaturized spacecraft technology has enabled the use of constellations of small spacecraft to achieve global observations of the atmosphere and geospace environment. The need for the spacecraft to be spread globally can be met even with a single launch vehicle by deploying the spacecraft in orbits with slightly different precession rates. Within one year, the spacecraft can be in orbits spread uniformly around the Earth. As many as ten to one hundred satellites can be launched from a single, commonly used launch vehicle, depending on their mass and volume. In this talk we describe the concepts behind achieving global coverage through a constellation of small spacecraft. We describe a small rugged solar occultation instrument that is well suited to this approach and is capable of obtaining high vertical resolution observations of a variety of species important to atmospheric and geospace research. Specific applications regarding stratosphere troposphere exchange are also discussed.

  3. Realistic Covariance Prediction For the Earth Science Constellations

    NASA Technical Reports Server (NTRS)

    Duncan, Matthew; Long, Anne

    2006-01-01

    Routine satellite operations for the Earth Science Constellations (ESC) include collision risk assessment between members of the constellations and other orbiting space objects. One component of the risk assessment process is computing the collision probability between two space objects. The collision probability is computed via Monte Carlo techniques as well as numerically integrating relative probability density functions. Each algorithm takes as inputs state vector and state vector uncertainty information for both objects. The state vector uncertainty information is expressed in terms of a covariance matrix. The collision probability computation is only as good as the inputs. Therefore, to obtain a collision calculation that is a useful decision-making metric, realistic covariance matrices must be used as inputs to the calculation. This paper describes the process used by NASA Goddard's Earth Science Mission Operations Project to generate realistic covariance predictions for three of the ESC satellites: Aqua, Aura, and Terra

  4. Constellation crew exploration vehicle, or CEV, is being prepare

    NASA Image and Video Library

    2007-11-27

    In Hangar N at NASA's Kennedy Space Center, a heat shield for the Constellation crew exploration vehicle, or CEV, is being prepared for a demonstration. A developmental heat shield for the Orion spacecraft is being tested and evaluated at Kennedy. The shield was designed and assembled by the Boeing Company in Huntington Beach, Calif., for NASA's Constellation Program. The thermal protection system manufacturing demonstration unit is designed to protect astronauts from extreme heat during re-entry to Earth's atmosphere from low Earth orbit and lunar missions. The CEV will be used to dock and gain access to the International Space Station, travel to the moon in the 2018 timeframe and play a crucial role in exploring Mars.

  5. Establishing a Formation of Small Satellites in a Lunar Flower Constellation

    NASA Astrophysics Data System (ADS)

    McManus, Lauren; Schaub, Hanspeter

    2016-12-01

    The success of previous lunar science missions can be expanded upon by using a constellation of satellites to increase the lunar surface coverage. A constellation could also serve as a communications or GPS network for a lunar human base. Small-sats, deployed from a single mothercraft, are proposed to achieve a lunar constellation. The establishment of a single- and multi-petal constellation is investigated where the mothercraft does the primary deployment maneuvers. The constellation lifetime and closed-loop maintenance are addressed once higher order lunar gravity fields and Earth/solar perturbations are included.

  6. Methodology and method and appartus for signaling with capacity optimized constellations

    NASA Technical Reports Server (NTRS)

    Barsoum, Maged F. (Inventor); Jones, Christopher R. (Inventor)

    2012-01-01

    Communication systems are described that use geometrically shaped constellations that have increased capacity compared to conventional constellations operating within a similar SNR band. In several embodiments, the geometrically shaped is optimized based upon a capacity measure such as parallel decoding capacity or joint capacity. In many embodiments, a capacity optimized geometrically shaped constellation can be used to replace a conventional constellation as part of a firmware upgrade to transmitters and receivers within a communication system. In a number of embodiments, the geometrically shaped constellation is optimized for an Additive White Gaussian Noise channel or a fading channel.

  7. Methodology and Method and Apparatus for Signaling with Capacity Optimized Constellations

    NASA Technical Reports Server (NTRS)

    Barsoum, Maged F. (Inventor); Jones, Christopher R. (Inventor)

    2017-01-01

    Communication systems are described that use geometrically shaped constellations that have increased capacity compared to conventional constellations operating within a similar SNR band. In several embodiments, the geometrically shaped is optimized based upon a capacity measure such as parallel decoding capacity or joint capacity. In many embodiments, a capacity optimized geometrically shaped constellation can be used to replace a conventional constellation as part of a firmware upgrade to transmitters and receivers within a communication system. In a number of embodiments, the geometrically shaped constellation is optimized for an Additive White Gaussian Noise channel or a fading channel.

  8. Real-time Retrieving Atmospheric Parameters from Multi-GNSS Constellations

    NASA Astrophysics Data System (ADS)

    Li, X.; Zus, F.; Lu, C.; Dick, G.; Ge, M.; Wickert, J.; Schuh, H.

    2016-12-01

    The multi-constellation GNSS (e.g. GPS, GLONASS, Galileo, and BeiDou) bring great opportunities and challenges for real-time retrieval of atmospheric parameters for supporting numerical weather prediction (NWP) nowcasting or severe weather event monitoring. In this study, the observations from different GNSS are combined together for atmospheric parameter retrieving based on the real-time precise point positioning technique. The atmospheric parameters retrieved from multi-GNSS observations, including zenith total delay (ZTD), integrated water vapor (IWV), horizontal gradient (especially high-resolution gradient estimates) and slant total delay (STD), are carefully analyzed and evaluated by using the VLBI, radiosonde, water vapor radiometer and numerical weather model to independently validate the performance of individual GNSS and also demonstrate the benefits of multi-constellation GNSS for real-time atmospheric monitoring. Numerous results show that the multi-GNSS processing can provide real-time atmospheric products with higher accuracy, stronger reliability and better distribution, which would be beneficial for atmospheric sounding systems, especially for nowcasting of extreme weather.

  9. Linking satellites via Earth hot spots and the Internet to form ad hoc constellations

    NASA Astrophysics Data System (ADS)

    Mandl, Daniel; Frye, Stu; Grosvenor, Sandra; Ingram, Mary Ann; Langley, John; Miranda, Felix A.; Lee, Richard Q.; Romanofsky, Robert R.; Zaman, Afroz; Popovic, Zoya; Sherwood, Robert L.; Chien, Steve; Davies, Ashley

    2005-01-01

    As more assets are placed in orbit, opportunities emerge to combine various sets of satellites in temporary constellations to perform collaborative image collections. Often, new operations concepts for a satellite or set of satellites emerge after launch. To the degree with which new space assets can be inexpensively and rapidly integrated into temporary or "ad hoc" constellations, will determine whether these new ideas will be implemented or not. On the Earth Observing 1 (EO-1) satellite, a New Millennium Program mission, a number of experiments were conducted and are being conducted to demonstrate various aspects of an architecture that, when taken as a whole, will enable progressive mission autonomy. In particular, the target architecture will use adaptive ground antenna arrays to form, as close as possible, the equivalent of wireless access points for low earth orbiting satellites. Coupled with various ground and flight software and the Internet, the architecture enables progressive mission autonomy. Thus, new collaborative sensing techniques can be implemented post-launch. This paper will outline the overall operations concept and highlight details of both the research effort being conducted in the area of adaptive antenna arrays and some of the related successful autonomy software that has been implemented using EO-1 and other operational satellites.

  10. Comparison between multi-constellation ambiguity-fixed PPP and RTK for maritime precise navigation

    NASA Astrophysics Data System (ADS)

    Tegedor, Javier; Liu, Xianglin; Ørpen, Ole; Treffers, Niels; Goode, Matthew; Øvstedal, Ola

    2015-06-01

    In order to achieve high-accuracy positioning, either Real-Time Kinematic (RTK) or Precise Point Positioning (PPP) techniques can be used. While RTK normally delivers higher accuracy with shorter convergence times, PPP has been an attractive technology for maritime applications, as it delivers uniform positioning performance without the direct need of a nearby reference station. Traditional PPP has been based on ambiguity-­float solutions using GPS and Glonass constellations. However, the addition of new satellite systems, such as Galileo and BeiDou, and the possibility of fixing integer carrier-phase ambiguities (PPP-AR) allow to increase PPP accuracy. In this article, a performance assessment has been done between RTK, PPP and PPP-AR, using GNSS data collected from two antennas installed on a ferry navigating in Oslo (Norway). RTK solutions have been generated using short, medium and long baselines (up to 290 km). For the generation of PPP-AR solutions, Uncalibrated Hardware Delays (UHDs) for GPS, Galileo and BeiDou have been estimated using reference stations in Oslo and Onsala. The performance of RTK and multi-­constellation PPP and PPP-AR are presented.

  11. Constellation Program: Lessons Learned. Volume 1; Executive Summary

    NASA Technical Reports Server (NTRS)

    Rhatigan, Jennifer L. (Editor)

    2011-01-01

    This document (Volume I) provides an executive summary of the lessons learned from the Constellation Program. A companion Volume II provides more detailed analyses for those seeking further insight and information. In this volume, Section 1.0 introduces the approach in preparing and organizing the content to enable rapid assimilation of the lessons. Section 2.0 describes the contextual framework in which the Constellation Program was formulated and functioned that is necessary to understand most of the lessons. Context of a former program may seem irrelevant in the heady days of new program formulation. However, readers should take some time to understand the context. Many of the lessons would be different in a different context, so the reader should reflect on the similarities and differences in his or her current circumstances. Section 3.0 summarizes key findings developed from the significant lessons learned at the program level that appear in Section 4.0. Readers can use the key findings in Section 3.0 to peruse for particular topics, and will find more supporting detail and analyses in Section 4.0 in a topical format. Appendix A contains a white paper describing the Constellation Program formulation that may be of use to readers wanting more context or background information. The reader will no doubt recognize some very similar themes from previous lessons learned, blue-ribbon committee reviews, National Academy reviews, and advisory panel reviews for this and other large-scale human spaceflight programs; including Apollo, Space Shuttle, Shuttle/Mir, and the ISS. This could represent an inability to learn lessons from previous generations; however, it is more likely that similar challenges persist in the Agency structure and approach to program formulation, budget advocacy, and management. Perhaps the greatest value of these Constellation lessons learned can be found in viewing them in context with these previous efforts to guide and advise the Agency and its

  12. Intercalibration of High Frequency Channels on GPM Constellation

    NASA Astrophysics Data System (ADS)

    Ebrahimi, H.; Datta, S.; Jones, L.

    2014-12-01

    The Global Precipitation Measuring (GPM) mission is an international effort to measure precipitation worldwide every three hours. The research objective is to reduce errors in global rainfall estimates associated with temporal/spatial sampling by using a constellation of satellites. Inter-calibration of microwave radiometer channels using the GPM Microwave Imager (GMI) is a challenging task. In GPM constellation we have a combination of cross track and conical scanner sensors, the goal is to make a consistent measurement between all the sensors in this constellation. GMI is a conical scanner and is going to be a reference for the calibration of all the other sensors in the constellation., almost all the sensors with channels lower than 89 GHz are conical scanners, the inter-calibration between conical scanners have been done successfully over years, But for frequencies equal and higher than 89GHz, there is SSMIS on the Defense Meteorological Satellite Program (DMSP) which is a conical scanner, other sensors such as ATMS on AMSU, MHS on NOAA 18, NOAA 19, METOP A and METOP B and SAPHIR on Megha -Tropique , are cross track sensors. For these sensors each Instantaneous Field of View (IFOV) has different Earth incidence angles (EIA) and different slant paths through the atmosphere while conical scanner has constant earth incidence angle for all IFOVs. Here the double difference (DD) technique, which has been successfully applied for imager channel calibration before, has been applied to sounder channels, also the effect of using different surface emissivity models such as Elsasser's and RSS model and atmosphere models such as Rosenkranz and MonoRTM models, in these frequencies has been investigated.

  13. Constellation Program walkback test in Bldg. 9NW - POGO Floor

    NASA Image and Video Library

    2007-03-21

    JSC2007-E-14579 (21 March 2007) --- Attired in a Mark III advanced space suit technology demonstrator, Brian Daniel participates in an extravehicular activity (EVA) systems engineering and integration (SE&I) test in the Space Vehicle Mockup Facility at Johnson Space Center. Data collected in the test will be used in development of the next generation of space suits that are being designed for use in the Constellation Program.

  14. Constellation-X Cylinder Figuring and Polishing Studies

    NASA Technical Reports Server (NTRS)

    Waluschka, Eugene; Arsenovic, Petar; Content, David; Saha, Timo; Strojny, Carl; Wright, Geraldine; Fleetwood, Charles

    2001-01-01

    In support of Goddard's Constellation-X mandrel manufacturing effort a series of fabrication experiments are being performed to determine a best approach. Currently, polishing immediately after diamond turning, produces a RMS surface roughness of 0.31 nm, on a nickel plated aluminum mandrel. Studies currently under way will incorporate an abrasive figuring step followed by a polishing operation. The current diamond turning, figuring and polishing procedures will be described and the results presented.

  15. Ocean altimetry and wind applications of a GNSS nanosatellite constellation

    NASA Astrophysics Data System (ADS)

    Rose, Randall; Ruf, Christopher S.; Seki, Haruo

    2012-11-01

    Recent developments in electronics and nanosatellite technologies combined with modeling techniques developed over the past 20 years have enabled a new class of altimetry and wind remote sensing capabilities that offer markedly improved performance over existing observatories while opening avenues to new applications. Most existing spaceborne ocean altimetry and wind observatories are in polar low Earth orbits that maximize global coverage but result in either large gaps at the tropics or long time intervals between geolocation measurement revisits. This, combined with their use of radar systems operating in the C and Ku-bands, obscures key information about the ocean and the global climate. Using GNSS-based bi-static scatterometry performed by a constellation of nanosatellites in a non-polar low Earth orbit could provide ocean altimetry and wind data with unprecedented temporal resolution and spatial coverage across the full dynamic range of ocean wind speeds in all precipitating conditions - all with a system cost substantially less than existing and planned systems. This paper contrasts the performance of a GNSS nanosatellite constellation with the existing monolithic remote sensing observatories while identifying synergies of the systems that can be exploited to achieve a more complete understanding of both ocean current and wind phenomena. Two specific applications are reviewed; ocean winds and ocean wave altimetry. The recently awarded Cyclone Global Navigation Satellite System (CYGNSS) mission will be used for the ocean wind comparison while a notional GNSS constellation will be used for comparison of the ocean wave altimetry application. Design requirements, applications, and system implementation are presented for the GNSS nanosatellite constellation.

  16. Imaging sensor constellation for tomographic chemical cloud mapping.

    PubMed

    Cosofret, Bogdan R; Konno, Daisei; Faghfouri, Aram; Kindle, Harry S; Gittins, Christopher M; Finson, Michael L; Janov, Tracy E; Levreault, Mark J; Miyashiro, Rex K; Marinelli, William J

    2009-04-01

    A sensor constellation capable of determining the location and detailed concentration distribution of chemical warfare agent simulant clouds has been developed and demonstrated on government test ranges. The constellation is based on the use of standoff passive multispectral infrared imaging sensors to make column density measurements through the chemical cloud from two or more locations around its periphery. A computed tomography inversion method is employed to produce a 3D concentration profile of the cloud from the 2D line density measurements. We discuss the theoretical basis of the approach and present results of recent field experiments where controlled releases of chemical warfare agent simulants were simultaneously viewed by three chemical imaging sensors. Systematic investigations of the algorithm using synthetic data indicate that for complex functions, 3D reconstruction errors are less than 20% even in the case of a limited three-sensor measurement network. Field data results demonstrate the capability of the constellation to determine 3D concentration profiles that account for ~?86%? of the total known mass of material released.

  17. Learning Curve for Teaching Constellations in a Planetarium

    NASA Astrophysics Data System (ADS)

    Hintz, Eric G.; Smith, N.; Moody, J. W.; Stephens, D. C.; Joner, M. D.; Hintz, M.; Lawler, J.; Jones, M.; Bench, N.

    2014-01-01

    As part of a larger project we have examined how students learn constellations in a planetarium environment. Students in our introductory descriptive astronomy class were given a 50 object quiz before any instruction. This quiz includes 30 constellations, 17 bright stars, two star clusters, and the Orion Nebula. In addition we gathered a small set of demographic information. After the initial quiz we tracked student scores through the semester to see how long it took for them to learn all 50 objects. We also plan to give a follow-up constellation quiz to students who have previously taken the quiz to test for retention. This will cover a time line for 6 months up to 4 years. We will present our early results from this study. This data will also be used as a baseline for a study of Head Mounted Displays to teach a deaf audience in a planetarium. This work is partially supported by funding from the National Science Foundation grant IIS-1124548 and the Sorenson Foundation.

  18. Launching Science: Science Opportunities Provided by NASA's Constellation System

    NASA Astrophysics Data System (ADS)

    Committee On Science Opportunities Enabled By NASA's Constellation System National Research Board

    In January 2004 NASA was given a new policy direction known as the Vision for Space Exploration. That plan, now renamed the United States Space Exploration Policy, called for sending human and robotic missions to the Moon, Mars, and beyond. In 2005 NASA outlined how to conduct the first steps in implementing this policy and began the development of a new human-carrying spacecraft known as Orion, the lunar lander known as Altair, and the launch vehicles Ares I and Ares V. Collectively, these are called the Constellation System. In November 2007 NASA asked the National Research Council (NRC) to evaluate the potential for new science opportunities enabled by the Constellation System of rockets and spacecraft. The NRC committee evaluated a total of 17 mission concepts for future space science missions. Of those, the committee determined that 12 would benefit from the Constellation System and five would not. This book presents the committee's findings and recommendations, including cost estimates, a review of the technical feasibility of each mission, and identification of the missions most deserving of future study.

  19. The Global Positioning System constellation as a space weather monitor

    NASA Astrophysics Data System (ADS)

    Morley, S.; Henderson, M. G.; Woodroffe, J. R.; Brito, T. V.

    2016-12-01

    The Global Positioning System (GPS) satellites are distributed across six orbital planes and follow near-circular orbits, with a 12 hour period, at an altitude of approximately 20200 km. The six orbital planes are distributed around the Earth and are nominally inclined at 55 degrees. Energetic particle detectors have been flown on the GPS constellation for more than two decades; by February 2016 there were 23 GPS satellites equipped with energetic particle instrumentation. The Combined X-ray Dosimeter (CXD), which is flown on 21 GPS satellites, has recently been cross-calibrated against electron data from the Van Allen Probes mission, demonstrating its utility for scientific research and radiation environment specification. Recently electron and proton flux data from these instruments, for the month of January 2014, have been publicly released. We will describe the GPS constellation from the perspective of its use as a monitor for space weather, review some of the key scientific results enabled by these instruments and show some recent observations from the constellation, including the 2015 St. Patrick's Day storm. Using data from multiple satellite missions we describe the dynamics of this storm in detail.

  20. Optimal Orbit Design for the Magnetospheric Imaging Constellation

    NASA Technical Reports Server (NTRS)

    Hughes, Steven P.; Bauer, Frank H. (Technical Monitor)

    2001-01-01

    The Magnetospheric Imaging Constellation (MagIC) is a NASA space science concept to study the Earth's Magnetosphere. The concept proposes to apply tomography techniques using an array of spacecraft to obtain three dimensional images of the Earth's magnetosphere. This paper presents an optimal orbit design to ensure that the constellation is in the desired region of the magnetosphere for maximum time. The solution is found using a steepest descent optimization algorithm that takes into account perturbations from the non-spherical Earth, drag, Sun, Moon and other significant bodies. The solution also satisfies constraints on maximum eclipse duration and geometry constraints to allow an adequate GPS navigation solution. We present three solutions depending upon the epoch of the primary science: vernal equinox, summer solstice, and a third midway between the vernal equinox and summer solstice. Orbit insertion is also considered. All spacecraft are assumed to be launched on a single vehicle into a nominal orbit and the (Delta)V's to achieve the nominal orbit are presented. After insertion into the nominal orbit, each spacecraft undergoes a phasing maneuver to place it in the appropriate position with respect to the rest of the constellation. We present a minimum fuel approach to maneuver each spacecraft from the nominal orbit into the desired final orbit.

  1. System design for OFDM systems with high-density constellations

    NASA Astrophysics Data System (ADS)

    Gu, Jian

    2001-10-01

    This paper addresses issues in designing OFDM systems with high-density constellations. To achieve high data throughput, many high-speed OFDM systems such as HiperLAN2 and IEEE 802.11a use high-density constellations such as 64QAM to reach up to 54Mbits/s over a 20 MHz frequency bandwidth. Compared with low-density constellation modulations, OFDM systems using M-QAM (M>=64) are very sensitive to analog circuits/components variations causing so-called I-Q imbalances. Moreover, for the purpose of high integration level and low cost, simple front-end radio/analog architectures such as direct conversion and low-IF are desirable but such architectures are even more sensitive to circuitry and component variation. We have developed a patent-pending technology called IQ-Balancing, which removes the adverse effect of I-Q imbalance and enables OFDM systems to have high tolerance to circuitry and component variations. With IQ-Balancing technology, direct conversion and low-IF architectures become very attractive for high-speed OFDM systems. Exploring further with IQ- balancing technology leads to a simple implementation of software Defined Radio (SDR).

  2. Sea State and Weather Assessment Capability for NASA's Constellation Program

    NASA Technical Reports Server (NTRS)

    Barbre, B. J.; Keller, V. W.

    2008-01-01

    Marine weather and related parameters such as wind, ocean wave height and period, air temperature, sea surface temperature, visibility, and potential for icing are critical to the design, operation, and safety of crewed space vehicles. The National Aeronautics and Space Administration's (NASA's) Constellation Program requires detailed assessment of marine weather related parameters that may be encountered during launch, abort, landing, and crew rescue operations for the crewed Ares/Orion space vehicles. This information is required for both space vehicle design and operational purposes. The space vehicles must be designed such that they can withstand the environment they are likely to encounter. The crewed Ares/Orion space vehicles will launch from NASA's Kennedy Space Center (KSC), Florida for both International Space Station (ISS) missions with 51.6 o inclination orbits and lunar missions with approximately 28 inclination orbits. Since both missions will fly over the Atlantic Ocean on ascent to orbit and will fly over the Pacific Ocean on descent from orbit, an unlikely but possible emergency abort could require parachuting the Orion capsule and crew into the ocean. This situation could potentially put the crew in an isolated and hazardous environment for several hours while they await rescue. Therefore, abort, landing, and crew rescue elements of the Constellation Program must address weather related parameters on a global scale. This paper describes buoy measurement data, sea surface temperature satellite data, and sea state computer model data that are being utilized by the Constellation Program to address these design and operational issues.

  3. Stereochemistry in self-assembled encapsulation complexes: Constellational isomerism

    PubMed Central

    Yamanaka, Masamichi; Shivanyuk, Alexander; Rebek, Julius

    2004-01-01

    A previously uncharacterized form of stereochemistry, constellational isomerism, is described. The isomerism arises from different arrangements of small-molecule guests in the space of a self-assembled, cylindrical host. The cylindrical host detains three molecules each of CHCl3, 1,2-dichloroethane, or isopropyl chloride. The exchange of guests in and out of the host is slow on the NMR time scale. The dimensions of the capsular host and the sizes of the guests hinder the mobility of molecules inside, and separate NMR signals are seen for guests at the ends of the capsule and those near its center. When two different guests are encapsulated, the spectra show up to four additional species: two sets of constellational isomers. In every pairwise combination of the three guests, all isomers could be identified. The equilibrium distributions of isomers depended on the concentrations of the guests in the bulk solution. The relative stability of the constellational isomers was a function of the polarity of the guest molecule and its ability to interact with the components of the capsule. The different arrangements represent information, and some possibilities for their use in data storage are proposed. PMID:14981269

  4. Sea State and Weather Capability for NASA's Constellation Program

    NASA Technical Reports Server (NTRS)

    Barbre, R. E.; Keller, V. W.

    2008-01-01

    Marine weather and related parameters such as wind, ocean wave height and period, air temperature, sea surface temperature, visibility, and potential for icing are critical to the design, operation, and safety of crewed space vehicles. The National Aeronautics and Space Administration's (NASA's) Constellation Program requires detailed assessment of marine weather related parameters that may be encountered during launch, abort, landing, and crew rescue operations for the crewed Axes/Orion space vehicles. This information is required for both space vehicle design and operational purposes. The space vehicles must be designed such that they cam withstand the environment they are likely to encounter. The crewed Axes/Orion space vehicles will launch from NASA's Kennedy Space Center (KSC), Florida for both International Space Station (ISS) missions with 51.6deg inclination orbits and lunar missions with approximately 280 inclination orbits. Since both missions will fly ever the Atlantic Ocean on ascent to orbit and will fly over the Pacific Ocean on descent from orbit, an unlikely but possible emergency abort could require parachuting the Orion capsule and crew into the ocean. This situation could potentially put the crew in an isolated and hazardous environment for severn hours while they await rescue. Therefore, abort, landing, and crew rescue elements of the Constellation Program must address weather related parameters on a global scale. This paper describes buoy measurement data, sea surface temperature satellite data, and sea state computer model data that are being utilized by the Constellation Program to address these design and operational issues.

  5. The Science Goals of the Constellation-X Mission

    NASA Technical Reports Server (NTRS)

    White, Nicholas E.; Tananbaum, Harvey; Weaver, Kimberly; Petre, Robert; Bookbinder, Jay

    2004-01-01

    The Constellation-X mission will address the questions: "What happens to matter close to a black hole?" and "What is Dark Energy?" These questions are central to the NASA Beyond Einstein Program, where Constellation-X plays a central role. The mission will address these questions by using high throughput X-ray spectroscopy to observe the effects of strong gravity close to the event horizon of black holes, and to observe the formation and evolution of clusters of galaxies in order to precisely determine Cosmological parameters. To achieve these primary science goals requires a factor of 25-100 increase in sensitivity for high resolution spectroscopy. The mission will also perform routine high- resolution X-ray spectroscopy of faint and extended X-ray source populations. This will provide diagnostic information such as density, elemental abundances, velocity, and ionization state for a wide range of astrophysical problems. This has enormous potential for the discovery of new unexpected phenomena. The Constellation-X mission is a high priority in the National Academy of Sciences McKee-Taylor Astronomy and Astrophysics Survey of new Astrophysics Facilities for the first decade of the 21st century.

  6. Acquisition through Horizontal Gene Transfer of Plasmid pSMA198 by Streptococcus macedonicus ACA-DC 198 Points towards the Dairy Origin of the Species

    PubMed Central

    Papadimitriou, Konstantinos; Anastasiou, Rania; Maistrou, Eleni; Plakas, Thomas; Papandreou, Nikos C.; Hamodrakas, Stavros J.; Ferreira, Stéphanie; Supply, Philip; Renault, Pierre; Pot, Bruno; Tsakalidou, Effie

    2015-01-01

    Background Streptococcus macedonicus is an intriguing streptococcal species whose most frequent source of isolation is fermented foods similarly to Streptococcus thermophilus. However, S. macedonicus is closely related to commensal opportunistic pathogens of the Streptococcus bovis/Streptococcus equinus complex. Methodology/Principal Findings We analyzed the pSMA198 plasmid isolated from the dairy strain Streptococcus macedonicus ACA-DC 198 in order to provide novel clues about the main ecological niche of this bacterium. pSMA198 belongs to the narrow host range pCI305/pWV02 family found primarily in lactococci and to the best of our knowledge it is the first such plasmid to be reported in streptococci. Comparative analysis of the pSMA198 sequence revealed a high degree of similarity with plasmids isolated from Lactococcus lactis strains deriving from milk or its products. Phylogenetic analysis of the pSMA198 Rep showed that the vast majority of closely related proteins derive from lactococcal dairy isolates. Additionally, cloning of the pSMA198 ori in L. lactis revealed a 100% stability of replication over 100 generations. Both pSMA198 and the chromosome of S. macedonicus exhibit a high percentage of potential pseudogenes, indicating that they have co-evolved under the same gene decay processes. We identified chromosomal regions in S. macedonicus that may have originated from pSMA198, also supporting a long co-existence of the two replicons. pSMA198 was also found in divergent biotypes of S. macedonicus and in strains isolated from dispersed geographic locations (e.g. Greece and Switzerland) showing that pSMA198’s acquisition is not a recent event. Conclusions/Significance Here we propose that S. macedonicus acquired plasmid pSMA198 from L. lactis via an ancestral genetic exchange event that took place most probably in milk or dairy products. We provide important evidence that point towards the dairy origin of this species. PMID:25584532

  7. SLR tracking of GNSS constellations for improved future ITRF realizations

    NASA Astrophysics Data System (ADS)

    Pavlis, Erricos C.; Koenig, Daniel; Kuzmicz-Cieslak, Magdalena

    The development of various future products for the Global Geodetic Observing System—GGOS, will rely heavily on the IAG Services that comprise GGOS, and the synergisms that can be built amongst them. The International Terrestrial Reference Frame (ITRF) is the first product that has been since long identified as the prime GGOS contribution by the organization itself, as well as the Services contributing to its development. The ITRF has been pledged to the international community as the GGOS contribution to the greater effort under the auspices of the Global Earth Observation System of Systems (GEOSS). To meet the stringent requirements imposed by the user community, GGOS set strict goals for the accuracy and stability attributes of its products. The goal for the ITRF accuracy in the definition of the origin is 1 mm or better with a temporal stability on the order of 0.1 mm/y, and similar numbers for the scale and orientation components. These goals are based on extensive deliberations within the Earth science community. None of the IAG positioning techniques can achieve this goal alone. In part this is due to the non-observability of certain TRF attributes from each technique. Another reason is the poor and deteriorating state of some of the tracking networks (ground segment) and in the case of SLR, a further limitation is the lack of suitable available targets (space segment). The poor distribution of the aging SLR tracking stations is now being addressed through an international effort to rebuilt the network (along with those of the other techniques) in a well-planned, optimized fashion that will address all of these concerns and ensure full support the GGOS requirements. As far as the rather small number of satellite targets in orbit that are useful for ITRF development, there are multiple in-progress approaches to address this also at the moment. A new cannonball target (LARES) was recently added to the existing two LAGEOS’ and efforts are being made to

  8. Triggered star formation in the LMC4/Constellation III region of the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Efremov, Yuri N.; Elmegreen, Bruce G.

    1998-09-01

    The origin of a regular, 600-pc-long arc of young stars and clusters in the Constellation III region of the Large Magellanic Cloud is considered. The circular form of this arc suggests that the pre-stellar gas was uniformly swept up by a central source of pressure. In the centre of the arc are six ~30-Myr-old A-type supergiant stars and a Cepheid variable of similar age, which may be related to the source of this pressure. We calculate the expansion of a bubble around a cluster of this age, and show that it could have triggered the formation of the arc at the right time and place. Surrounding the central old stars and extending well outside the young arc is the LMC4 superbubble and giant HI shell. We show how this superbubble and shell could have formed by the continued expansion of the 15-Myr-old cavity, following star formation in the arc and the associated new pressures. The age sequence proposed here was not evident in the recent observations by Olsen et al. and Braun et al. because the first generation stars in the centre of the LMC superbubble are relatively faint and scarce compared to the more substantial population of stars less than 15 Myr old that formed throughout the region in a second generation. These considerations lead to an examination of the origin of the LMC4/Constellation III region and other large rings in the LMC and other galaxies. Their size and circularity could be the result of low galactic shear and a thick disc, with several generations of star formation in their interiors now too faint to be seen.

  9. Microscopic origin of the 1.3 G{sub 0} conductance observed in oxygen-doped silver quantum point contacts

    SciTech Connect

    Tu, Xingchen; Wang, Minglang; Hou, Shimin; Sanvito, Stefano

    2014-11-21

    Besides the peak at one conductance quantum, G{sub 0}, two additional features at ∼0.4 G{sub 0} and ∼1.3 G{sub 0} have been observed in the conductance histograms of silver quantum point contacts at room temperature in ambient conditions. In order to understand such feature, here we investigate the electronic transport and mechanical properties of clean and oxygen-doped silver atomic contacts by employing the non-equilibrium Green's function formalism combined with density functional theory. Our calculations show that, unlike clean Ag single-atom contacts showing a conductance of 1 G{sub 0}, the low-bias conductance of oxygen-doped Ag atomic contacts depends on the number of oxygen impurities and their binding configuration. When one oxygen atom binds to an Ag monatomic chain sandwiched between two Ag electrodes, the low-bias conductance of the junction always decreases. In contrast, when the number of oxygen impurities is two and the O-O axis is perpendicular to the Ag-Ag axis, the transmission coefficients at the Fermi level are, respectively, calculated to be 1.44 for the junction with Ag(111) electrodes and 1.24 for that with Ag(100) electrodes, both in good agreement with the measured value of ∼1.3 G{sub 0}. The calculated rupture force (1.60 nN for the junction with Ag(111) electrodes) is also consistent with the experimental value (1.66 ± 0.09 nN), confirming that the measured ∼1.3 G{sub 0} conductance should originate from Ag single-atom contacts doped with two oxygen atoms in a perpendicular configuration.

  10. Massive pulsating stars observed by BRITE-Constellation. I. The triple system β Centauri (Agena)

    NASA Astrophysics Data System (ADS)

    Pigulski, A.; Cugier, H.; Popowicz, A.; Kuschnig, R.; Moffat, A. F. J.; Rucinski, S. M.; Schwarzenberg-Czerny, A.; Weiss, W. W.; Handler, G.; Wade, G. A.; Koudelka, O.; Matthews, J. M.; Mochnacki, St.; Orleański, P.; Pablo, H.; Ramiaramanantsoa, T.; Whittaker, G.; Zocłońska, E.; Zwintz, K.

    2016-04-01

    modes originate in which component did not succeed, but there is potential for using this method when more BRITE data become available. Conclusions: Agena seems to be one of very few rapidly rotating massive objects with rich p- and g-mode spectra, and precisely known masses. It can therefore be used to gain a better understanding of the excitation of pulsations in relatively rapidly rotating stars and their seismic modeling. Lacking proper mode identification, the pulsation frequencies found in β Cen cannot yet be used to constrain the internal structure of the components, but it may be possible to achieve this in the future with the use of spectroscopy and spectropolarimetry. In particular, these kinds of data can be used for mode identification since they provide new radial velocities. In consequence, they may help to improve the orbital solution, derive more precise masses, magnetic field strength and geometry, inclination angles, and reveal rotation periods. They may also help to assign pulsation frequencies to components. Finally, the case studied here illustrates the potential of BRITE-Constellation data for the detection of rich-frequency spectra of small-amplitude modes in massive pulsating stars. Based on data collected by the BRITE-Constellation satellite mission, built, launched and operated thanks to support from the Austrian Aeronautics and Space Agency and the University of Vienna, the Canadian Space Agency (CSA) and the Foundation for Polish Science & Technology (FNiTP MNiSW) and National Centre for Science (NCN).

  11. The X-ray Microcalorimeter Spectrometer (XMS): A Reference Cryogenic Instrument Design for Constellation-X

    NASA Technical Reports Server (NTRS)

    Whitehouse, Paul L.

    2003-01-01

    Constellation-X, a mission now belonging to the Beyond Einstein initiative, is being planned to inherit the x-ray sky from Chandra, XMM-Newton and Astro-E. The first two of four observatories in the constellation will be launched together in 2013 and followed a year later by the launch of the remaining two. The four will independently orbit the Sun-Earth Lagrange point L2. An instrument compliment resides in the Focal Plane Module (FPM) of each observatory 10 m from the Optics Module and consists of three Hard X-ray Telescope (HXT) detectors, a Reflection Grating Spectrometer (RGS) focal plane CCD camera and an X-ray Microcalorimeter Spectrometer (XMS). Instrument awards are scheduled for early 2006. The reference detector for XMS is a 32 x 32 array of microcalorimetric superconducting Transition Edge Sensors (TES). Each pixel casts a variable resistance in a SQUID based multiplexed readout circuit which is coupled to series SQUID arrays for amplification and finally read out by external electronics. A multi-stage continuous ADR will provide the stable 50 mK desired for the TES array and a stable 1 K for the series SQUID arrays while also lifting thermal parasitic and inefficiency loads to a 6 K cryocooler interface. The 6 K cryocooler is expected to emerge from the joint-project Advanced Cryocooler Technology Development Program (ACTDP) in which Constellation-X is an active participant. Project Pre-Formulation activities are marked by extensive technology development necessitating early, but realistic, thermal and cooling load requirements for ADR and ACTDP-cryocooler design points. Such requirements are driven by the encompassing XMS cryostat and ultimately by the thermal environment imposed by the FPM. It is further desired that the XMS instrument be able to operate on its side in the laboratory, with a warm vacuum shell, during an extensive calibration regime. It is that reference system design of the XMS instrument (microcalorimeter, ADR, cryocooler and

  12. The X-ray Microcalorimeter Spectrometer (XMS): A Reference Cryogenic Instrument Design for Constellation-X

    NASA Technical Reports Server (NTRS)

    Whitehouse, Paul L.

    2003-01-01

    Constellation-X, a mission now belonging to the Beyond Einstein initiative, is being planned to inherit the x-ray sky from Chandra, XMM-Newton and Astro-E. The first two of four observatories in the constellation will be launched together in 2013 and followed a year later by the launch of the remaining two. The four will independently orbit the Sun-Earth Lagrange point L2. An instrument compliment resides in the Focal Plane Module (FPM) of each observatory 10 m from the Optics Module and consists of three Hard X-ray Telescope (HXT) detectors, a Reflection Grating Spectrometer (RGS) focal plane CCD camera and an X-ray Microcalorimeter Spectrometer (XMS). Instrument awards are scheduled for early 2006. The reference detector for XMS is a 32 x 32 array of microcalorimetric superconducting Transition Edge Sensors (TES). Each pixel casts a variable resistance in a SQUID based multiplexed readout circuit which is coupled to series SQUID arrays for amplification and finally read out by external electronics. A multi-stage continuous ADR will provide the stable 50 mK desired for the TES array and a stable 1 K for the series SQUID arrays while also lifting thermal parasitic and inefficiency loads to a 6 K cryocooler interface. The 6 K cryocooler is expected to emerge from the joint-project Advanced Cryocooler Technology Development Program (ACTDP) in which Constellation-X is an active participant. Project Pre-Formulation activities are marked by extensive technology development necessitating early, but realistic, thermal and cooling load requirements for ADR and ACTDP-cryocooler design points. Such requirements are driven by the encompassing XMS cryostat and ultimately by the thermal environment imposed by the FPM. It is further desired that the XMS instrument be able to operate on its side in the laboratory, with a warm vacuum shell, during an extensive calibration regime. It is that reference system design of the XMS instrument (microcalorimeter, ADR, cryocooler and

  13. System and antenna design considerations for highly elliptical orbits as applied to the proposed Archimedes Constellation

    NASA Technical Reports Server (NTRS)

    Paynter, C.; Cuchanski, M.

    1995-01-01

    The paper discusses various aspects of the system design for a satellite in a highly elliptical inclined orbit, and presents a number of antenna design options for the proposed Archimedes mission. A satellite constellation was studied for the provision of multi media communication services in the L and S Band for northern latitudes. The inclined elliptical orbit would allow coverage of Europe, America, and East Asia. Using Canada and North America as the baseline coverage area, this paper addresses system considerations such as the satellite configuration and pointing, beam configuration, and requirements for antennas. A trade-off is performed among several antenna candidates including a direct radiating array, a focal-fed reflector, and a single reflector imaging system. Antenna geometry, performance, and beam forming methods are described. The impact of the designs on the antenna deployment is discussed.

  14. System and antenna design considerations for highly elliptical orbits as applied to the proposed Archimedes Constellation

    NASA Technical Reports Server (NTRS)

    Paynter, C.; Cuchanski, M.

    1995-01-01

    The paper discusses various aspects of the system design for a satellite in a highly elliptical inclined orbit, and presents a number of antenna design options for the proposed Archimedes mission. A satellite constellation was studied for the provision of multi media communication services in the L and S Band for northern latitudes. The inclined elliptical orbit would allow coverage of Europe, America, and East Asia. Using Canada and North America as the baseline coverage area, this paper addresses system considerations such as the satellite configuration and pointing, beam configuration, and requirements for antennas. A trade-off is performed among several antenna candidates including a direct radiating array, a focal-fed reflector, and a single reflector imaging system. Antenna geometry, performance, and beam forming methods are described. The impact of the designs on the antenna deployment is discussed.

  15. Inter-calibrating Brightness Temperatures of a Constellation of Radiometers

    NASA Technical Reports Server (NTRS)

    Stocker, Erich Franz; Berg, Wesley; Kummerow, Christian; Stout, John

    2006-01-01

    In 2010, the National Aeronautics and Space Agency (NASA) of the U.S.A. and the Japanese Exploration Agency (JAXA) of Japan in cooperation with other U.S. and international partners will launch the Global Precipitation Measurement (GPM) mission. The mission center-piece is a core U.S. provided satellite holding a scanning microwave imager provided by the U.S. A. and a dual-frequency precipitation radar provided by Japan. The core satellite is in a 65 deg inclination (the current Tropical Rainfall Measuring Mission -TRMM is in a 35 deg inclination). Joining the core satellite are a constellation of approximately 8 satellites containing scanning radiometers. The purpose of the constellation is to increase the global sampling capability of the mission. One constellation satellite will be provided by NASA. Some of the constellation radiometers will provided by other U.S. agencies with existing (e.g. SSMI/S) or planned (NPOESS) radiometer assets. International groups have also expressed interest in contributing to the GPM mission including providing radiometer data for the GPM constellation. The use of a heterogeneous group of scanning radiometers each with its own unique purpose, characteristics and calibration offers a significant challenge for combining brightness temperatures or rain retrievals to create meaningful combined global radiometer products. However, the availability of active dual precipitation radar on the GPM core in combination with a well-calibrated radiometer on the same platform offers the possibility of inter-calibrating the constellation radiometers using the core satellite as a calibrator. This paper describes a joint NASA/GSFC and Colorado State University prototype effort at inter-calibrating existing radiometers using such a core calibrator approach. In the prototype, existing radiometers (i.e. SSM/I and AMSR-E) are intercalibrated, as required, using the TRMM Precipitation Radar (PR) and TRMM Microwave Imager (TMI) as the calibration core

  16. Micro-Satellite Constellation for Global Surface Water Data

    NASA Astrophysics Data System (ADS)

    Apperson, A. T.; Vanderbilt, V. C.

    2011-12-01

    Alsdorf et al. [1] have proposed a Ka band interferometric radar system for global monitoring of surface waters from space. We explore the feasibility of a constellation of micro-satellites with optical sensors measuring the sun's specular reflection by surface waters. Our approach, which is complementary to that of Alsdorf et al., would provide weekly global coverage with a 10m ground spatial resolution if a six micro-satellite constellation used a 0.7° ground swath width and the ADEOS 1 orbital parameters. Optical sensing has three main obstacles; smoke, clouds and canopy structures. The sun's specular reflection provides a signal strength that, from observations, penetrates aerosols with an optical depth approaching 1.0 and provides detection down to perhaps 1/32 of a pixel, which would potentially allow detection of surface waters under many plant canopies. Our system would provide data to help answer Alsdorf's question, "What is the spatial and temporal variability in terrestrial surface water storage, and how can we predict these variations more accurately?" [1] In addition, modifying the arrangement of the satellites in the constellation could potentially provide data on the canopy structure. Including an additional instrument could provide estimates on atmospheric column methane and other estimates of other atmospheric trace gases concentration. [2] [1] D. E. Alsdorf, E. Rodríguez, and D. P. Lettenmaier, "Measuring surface water from space," Rev. Geophys, vol. 45, no. 2, pp. 1-24, 2007. [2] North F. Larsen and Knut Stamnes, "Methane detection from space: use of sunglint", Opt. Eng. 45, 016202 (Feb 01, 2006); doi:10.1117/1.2150835

  17. Beta Pic observations requested for BRITE-Constellation

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2017-01-01

    The AAVSO is part of the BRITE-Constellation Ground Based Observations Team (GBOT), supporting cutting-edge science from the BRITE-Constellation satellites and coordinating with BRITE-Constellation scientist Dr. Konstanze Zwintz (Universitaet Innsbruck) and her team. The delta Scuti star beta Pic (NSV 16683) (3.80-3.86V) is one of the BRITE stars being focused on during this season. Bet Pic is particularly interesting now because a transit of the star's planet's Hill sphere (the region around a planet in which it dominates the attraction of satellites) is predicted to occur during 2017-2018. Ongoing observations beginning now are valuable to establish a baseline prior to the transit. The AAVSO's webpage on the BRITE target stars was updated in November with information on bet Pic from Dr. Zwintz. AAVSO observers with appropriate equipment and located at a southern enough latitude are encouraged to observe bet Pic. Its brightness makes bet Pic well suited to PEP and DSLR photometry; CCD photometry is also possible. However, great care must be taken by all observers, especially those using CCD, to avoid saturation. As the amplitude of this star is very small, visual observations are very difficult, but they are welcome. Multicolor (BVR) photometry better than 0.01 magnitude and time-series observations with a cadence of a few minutes (less than 10 minutes) are requested beginning now and continuing at least through 2017 and likely through 2018. The precision and cadence required are essential in order for the data to be most useful for studying the transit. Spectroscopists wishing to participate should submit their spectra directly to Dr. Konstanze Zwintz (konstanze.zwintz@uibk.ac.at). Finder charts with sequence may be created using the AAVSO Variable Star Plotter (https://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details.

  18. LEO constellations - Quo vadis after end-of-mission?

    NASA Astrophysics Data System (ADS)

    Hörl, Kay-Uwe; John, Rüdiger; Sarrocco, Claudia

    2001-10-01

    Constellations in low-Earth orbit (LEO) will increase the number of debris objects if they are not removed from their orbit after end of mission. This paper addresses two issues: the technical aspects dealing with the collision risk during de-orbiting (calculated with the MASTER model) and the political and legal aspects covering the liability question. Prerequisites for a code of conduct are outlined that could be agreed upon internationally to encourage spacecraft operators to de-orbit their spacecraft. If such measures were to be taken, a mass accumulation could be prevented at disposal orbits above 2000 km, thus preserving these regions useful for future generations.

  19. Multi-Objective Scheduling for the Cluster II Constellation

    NASA Technical Reports Server (NTRS)

    Johnston, Mark D.; Giuliano, Mark

    2011-01-01

    This paper describes the application of the MUSE multiobjecctive scheduling framework to the Cluster II WBD scheduling domain. Cluster II is an ESA four-spacecraft constellation designed to study the plasma environment of the Earth and it's magnetosphere. One of the instruments on each of the four spacecraft is the Wide Band Data (WBD) plasma wave experiment. We have applied the MUSE evolutionary algorithm to the scheduling problem represented by this instrument, and the result has been adopted and utilized by the WBD schedulers for nearly a year. This paper describes the WBD scheduling problem, its representation in MUSE, and some of the visualization elements that provide insight into objective value tradeoffs.

  20. Trade-Space Analysis Tool for Constellations (TAT-C)

    NASA Technical Reports Server (NTRS)

    Le Moigne, Jacqueline; Dabney, Philip; de Weck, Olivier; Foreman, Veronica; Grogan, Paul; Holland, Matthew; Hughes, Steven; Nag, Sreeja

    2016-01-01

    Traditionally, space missions have relied on relatively large and monolithic satellites, but in the past few years, under a changing technological and economic environment, including instrument and spacecraft miniaturization, scalable launchers, secondary launches as well as hosted payloads, there is growing interest in implementing future NASA missions as Distributed Spacecraft Missions (DSM). The objective of our project is to provide a framework that facilitates DSM Pre-Phase A investigations and optimizes DSM designs with respect to a-priori Science goals. In this first version of our Trade-space Analysis Tool for Constellations (TAT-C), we are investigating questions such as: How many spacecraft should be included in the constellation? Which design has the best costrisk value? The main goals of TAT-C are to: Handle multiple spacecraft sharing a mission objective, from SmallSats up through flagships, Explore the variables trade space for pre-defined science, cost and risk goals, and pre-defined metrics Optimize cost and performance across multiple instruments and platforms vs. one at a time.This paper describes the overall architecture of TAT-C including: a User Interface (UI) interacting with multiple users - scientists, missions designers or program managers; an Executive Driver gathering requirements from UI, then formulating Trade-space Search Requests for the Trade-space Search Iterator first with inputs from the Knowledge Base, then, in collaboration with the Orbit Coverage, Reduction Metrics, and Cost Risk modules, generating multiple potential architectures and their associated characteristics. TAT-C leverages the use of the Goddard Mission Analysis Tool (GMAT) to compute coverage and ancillary data, streamlining the computations by modeling orbits in a way that balances accuracy and performance.TAT-C current version includes uniform Walker constellations as well as Ad-Hoc constellations, and its cost model represents an aggregate model consisting of

  1. Development of Constellation-X Optics Technologies at MSFC

    NASA Technical Reports Server (NTRS)

    ODell, S. L.; Jones, W. D.; Smith, W. S.; Ramsey, B. D.; Engelhaupt, D.

    2000-01-01

    One of the major technological challenges for the Constellation X-ray Mission is the development of light-weight, high-resolution, grazing-incidence optics. NASA's Marshall Space Flight Center is developing and evaluating candidate technologies, based upon full-shell replication off precision mandrels. Here we report on recent progress in meeting the weight and imaging-performance requirements, using very thin, high-strength electroformed nickel alloys. In addition, we briefly describe MSFC's optics fabrication, metrology, and x-ray test facilities.

  2. Development of Constellation-X Optics Technologies at MSFC

    NASA Technical Reports Server (NTRS)

    Odell, S. L.; Jones, W. D.; Smith, W. S.; Ramsey, B. D.

    1999-01-01

    One of the major technological challenges for the Constellation X-ray Mission is the development of light-weight, high-resolution, grazing-incidence optics. NASA's Marshall Space Flight Center is developing and evaluating candidate technologies, based upon full-shell replication off precision mandrels. Here we report on recent progress in meeting the weight and imaging-performance requirements, using very thin, high-strength electroformed nickel alloys. In addition, we briefly describe MSFC's optics fabrication, metrology, and x-ray test facilities.

  3. Development of Constellation-X Optics Technologies at MSFC

    NASA Technical Reports Server (NTRS)

    Ramsey, B. D.; ODell, S. L.; Jones, W. D.; Smith, W. S.; Engelhaupt, D.

    2000-01-01

    One of the major technological challenges for the Constellation X-ray Mission is the development of light-weight, high-resolution, grazing-incidence optics. NASA's Marshall Space Flight Center is developing and evaluating candidate technologies, based upon full-shell replication off precision mandrels. Here we report on recent progress in meeting the weight and imaging-performance requirements, using very thin, high- strength electroformed nickel alloys, In addition, we briefly describe MSFC's optics fabrication, metrology, and x-ray test facilities.

  4. Development of Constellation-X Optics Technologies at MSFC

    NASA Technical Reports Server (NTRS)

    Ramsey, B. D.; ODell, S. L.; Jones, W. D.; Smith, W. S.; Engelhaupt, D.

    2000-01-01

    One of the major technological challenges for the Constellation X-ray Mission is the development of light-weight, high-resolution, grazing-incidence optics. NASA's Marshall Space Flight Center is developing and evaluating candidate technologies, based upon full-shell replication off precision mandrels. Here we report on recent progress in meeting the weight and imaging-performance requirements, using very thin, high- strength electroformed nickel alloys, In addition, we briefly describe MSFC's optics fabrication, metrology, and x-ray test facilities.

  5. Development of Constellation-X Optics Technologies at MSFC

    NASA Technical Reports Server (NTRS)

    Odell, S. L.; Jones, W. D.; Smith, W. S.; Ramsey, B. D.

    1999-01-01

    One of the major technological challenges for the Constellation X-ray Mission is the development of light-weight, high-resolution, grazing-incidence optics. NASA's Marshall Space Flight Center is developing and evaluating candidate technologies, based upon full-shell replication off precision mandrels. Here we report on recent progress in meeting the weight and imaging-performance requirements, using very thin, high-strength electroformed nickel alloys. In addition, we briefly describe MSFC's optics fabrication, metrology, and x-ray test facilities.

  6. Development of Constellation-X Optics Technologies at MSFC

    NASA Technical Reports Server (NTRS)

    ODell, S. L.; Jones, W. D.; Smith, W. S.; Ramsey, B. D.; Engelhaupt, D.

    2000-01-01

    One of the major technological challenges for the Constellation X-ray Mission is the development of light-weight, high-resolution, grazing-incidence optics. NASA's Marshall Space Flight Center is developing and evaluating candidate technologies, based upon full-shell replication off precision mandrels. Here we report on recent progress in meeting the weight and imaging-performance requirements, using very thin, high-strength electroformed nickel alloys. In addition, we briefly describe MSFC's optics fabrication, metrology, and x-ray test facilities.

  7. Spacecraft autonomy using onboard processing for a SAR constellation mission

    NASA Technical Reports Server (NTRS)

    Sherwood, R. L.; Chien, S.; Castano, R.

    2002-01-01

    The Autonomous Sciencecraft Experiment (ASE) will fly onboard the Air Force TechSat 21 constellation of three spacecraft scheduled for launch in 2006. ASE uses onboard continuous planning, robust task and goal-based execution, model-based mode identification and reconfiguration, and onboard machine learning and pattem recognition to radically increase science retum by enabling intelligent downlink selection and autonomous retargeting. Demonstration of these capabilities in a flight environment will open up tremendous new opportunities in planetary science, space physics, and earth science that would be unreachable without this technology.

  8. Multi-Objective Scheduling for the Cluster II Constellation

    NASA Technical Reports Server (NTRS)

    Johnston, Mark D.; Giuliano, Mark

    2011-01-01

    This paper describes the application of the MUSE multiobjecctive scheduling framework to the Cluster II WBD scheduling domain. Cluster II is an ESA four-spacecraft constellation designed to study the plasma environment of the Earth and it's magnetosphere. One of the instruments on each of the four spacecraft is the Wide Band Data (WBD) plasma wave experiment. We have applied the MUSE evolutionary algorithm to the scheduling problem represented by this instrument, and the result has been adopted and utilized by the WBD schedulers for nearly a year. This paper describes the WBD scheduling problem, its representation in MUSE, and some of the visualization elements that provide insight into objective value tradeoffs.

  9. The large Curie-point depth and thermal lithospheric thickness of the Yellowstone hotspot: a nonplume model for the origin of the Yellowstone hotspot?

    NASA Astrophysics Data System (ADS)

    Wang, J.; Li, C.

    2012-12-01

    The western United States has experienced extensive magmatism and large-scale extension during the Cenozoic. The most noticeable magmatism since the mid-Miocene has been associated with the Columbia River Flood Basalts (CRFB) and Eastern Snake River Plain hotspot track (ESRP). Most studies postulated that the CRFB and ESRP arise from a mantle plume. We present our recent inversion of Curie-point depth (Zb) of the western United States based on fractal spectral analyses of magnetic anomalies. Our result indicates a shallow Zb in the ESRP and an intermediate Zb in the most area of the CRFB, but a deep Zb (~ 35 km) around the Yellowstone hotspot. We also calculate the Moho temperature and thermal lithospheric thickness to constrain the crustal geothermal state using the 1D stable thermal conduction equation with a temperature-dependent thermal conductivity model, taking the Curie temperature of 550°C as one of the boundary conditions. The thermal lithospheric thickness around the Yellowstone is about 100 km. Both the deep Zb and large thermal lithospheric thickness in the Yellowstone are not in line with a mantle plume model for the origin of Yellowstone hotspot. In addition, the imaged Moho temperature is low, about 570°C, around the Yellowstone caldera. Thus, we favor an upper mantle source for the origin of the Yellowstone hotspot. The extension of the northern Basin and Range Province (B&R) can date back to at least 30 Ma, initiated in an intra-arc and back-arc setting during the steepening of the subducting Farallon slab between 40~20 Ma and then strongly influenced by the lateral traction of the San Andreas transform fault. We prefer that the succeeding extension of the northwestern part of the B&R induced mantle upwelling, which is responsible for the voluminous tholeiitic basalt of the CRFB erupted from ~16.6 Ma in Steens Mountain and almost the coeval eruption of the ESRP at the same position. We also find a lineament and two arc-shaped belts concaving

  10. Libration point orbits for lunar global positioning systems

    NASA Astrophysics Data System (ADS)

    Ren, Yuan; Shan, Jinjun

    2013-04-01

    With the development of lunar exploration, a lunar global positioning system (LGPS) is demanded for both on-ground and in-flight lunar exploration missions. The traditional configuration of constellation requires at least eighteen satellites to cover the whole lunar surface continuously. In this paper, the configurations of the libration point orbits (LPOs) constellations are investigated. By using the constellations on the Earth-Moon L1 and L2 LPOs, the basic functions of the LGPS can be realized by using eight to fourteen satellites. First, the LPO and the combinations of LPOs, which can be used in the constellations of the LGPS, are investigated. The criteria and procedures of the configuration design are introduced. Second, the configurations of LPOs constellations are investigated in the Earth-Moon circular-restricted three-body problem (CR3BP). The size of the LPOs and the distribution of the satellites on these LPOs are determined by using an exhaustive algorithm and a global optimization method, respectively. The key performance parameters of these constellations are computed. Third, the constellations with good performance in the CR3BP are redesigned in the more accurate Earth-Moon based Sun-perturbed bicircular four-body problem (B4BP). Moreover, in order to avoid the ground coverage problem caused by the perturbation of the Sun, some modifications are implemented, and the configuration of the no blind area LGPS in the B4BP is obtained.

  11. X-Ray Testing Constellation-X Optics at MSFC's 100-m Facility

    NASA Technical Reports Server (NTRS)

    O'Dell, Stephen; Baker, Markus; Content, David; Freeman, Mark; Glenn, Paul; Gubarev, Mikhail; Hair, Jason; Jones, William; Joy, Marshall

    2003-01-01

    In addition to the 530-m-long X-Ray Calibration Facility (XRCF), NASA's Marshall Space Flight Center (MSFC) operates a 104-m-long (source-to-detector) X-ray-test facility. Originally developed and still occasionally used for stray-light testing of visible-fight optical systems, the so-called "Stray-Light Facility" now serves primarily as a convenient and inexpensive facility for performance evaluation and calibration of X-ray optics and detectors. The facility can accommodate X-ray optics up to about 1-m diameter and 12-m focal length. Currently available electron-impact sources at the facility span the approximate energy range 0.2 to 100 keV, thus supporting testing of soft- and hard-X-ray optics and detectors. Available MSFC detectors are a front-illuminated CCD (charge-coupled device) and a scanning CZT (cadmium--zinc--telluride) detector, with low-energy cut-offs of about 0.8 and 3 keV, respectively. In order to test developmental optics for the Constellation-X Project, led by NASA's Goddard Space Flight Center (GSFC), MSFC undertook several enhancements to the facility. Foremost among these was development and fabrication of a five-degree-of-freedom (5-DoF) optics mount and control system, which translates and tilts the user-provided mirror assembly suspended from its interface plate. Initial Constellation-X tests characterize the performance of the Optical Alignment Pathfinder Two (OAP2) for the large Spectroscopy X-ray Telescope (SXT) and of demonstration mirror assemblies for the Hard X-ray Telescope (HXT). With the Centroid Detector Assembly (CDA), used for precision alignment of the Chandra (nee AXAF) mirrors, the Constellation-X SXT Team optically aligned the individual mirrors of the OAPZ at GSFC. The team then developed set-up and alignment procedures, including transfer of the alignment from the optical alignment facility at GSFC to the X-ray test facility at MSFC, using a reference flat and fiducials. The OAPZ incorporates additional ancillary

  12. Investigating GAIM-GM’s Capability to Sense Ionospheric Irregularities via Walker Satellite Constellations

    DTIC Science & Technology

    2015-03-26

    INVESTIGATING GAIM-GM’S CAPABILITY TO SENSE IONOSPHERIC IRREGULARITIES VIA WALKER SATELLITE CONSTELLATIONS THESIS Brandon T. McClung, Captain, USAF...CAPABILITY TO SENSE IONOSPHERIC IRREGULARITIES VIA WALKER SATELLITE CONSTELLATIONS THESIS Presented to the Faculty Department of Engineering Physics...WALKER SATELLITE CONSTELLATIONS THESIS Brandon T. McClung, B.S. Captain, USAF Committee Membership: Dr. William F. Bailey Chair Dr. Stephen T. Fiorino

  13. Monitoring of Arctic Conditions from a Virtual Constellation of Synthetic Aperture Radar Satellites

    DTIC Science & Technology

    2014-09-30

    Constellation of Synthetic Aperture Radar Satellites RSMAS – Department of Ocean Sciences Center for Southeastern Tropical Advanced Remote Sensing...fax: (305) 421-4696 email: pminnett@rsmas.miami.edu Award Number: N00014-12-1-0448 LONG-TERM GOALS Utilize a constellation of satellite...OBJECTIVES a) Provide daily Arctic situational awareness from the CSTARS SAR satellite constellation . b) Develop a Neural Network algorithm for ice-type

  14. Modelling of Picosatellite Constellation-Based Network and Effects on Quality of Service

    DTIC Science & Technology

    2015-03-01

    PICOSATELLITE CONSTELLATION - BASED NETWORK AND EFFECTS ON QUALITY OF SERVICE by Jingyi Chiew March 2015 Thesis Advisor: Alex Bordetsky Second...COVERED March 2015 Master ’s Thesis 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS MODELLING OF PICOSATELLITE CONSTELLATION -BASED NETWORK AND EFFECTS ON...minia.tw-ized satellites is known as the pi co satellite. In order to evaluate the performance of the picosatellite constellation -based network, a

  15. High-pressure xenon detector development at Constellation Technology Corporation

    NASA Astrophysics Data System (ADS)

    Austin, Robert A.

    2007-08-01

    Xenon-filled ionization detectors, due to their high atomic number fill gas ( Z=54), moderate densities (˜0.3-0.5 g/cm 3) and good energy resolution (2-4% at 662 keV), fill an important niche between more familiar technologies such as NaI(Tl) scintillators and germanium detectors. Until recently, difficulties with obtaining sufficient xenon purity, reducing microphonic sensitivity, and developing low-noise electronics compatible with small ionization signals have hampered the development of this nuclear detection field. Constellation Technology Corporation, whose experience with xenon detectors goes back to the mid 1990s, has made significant progress in these areas and has developed a commercial line of detectors with active volumes ranging from small (35 g Xe) to large (1400 g Xe). Current applications for Constellation's detectors are principally in the area of defense (Unmanned Aerial Vehicles and Advanced Spectroscopic Portals), but as awareness of this technology grows, it will surely find applications in a much expanded range of fields.

  16. Dynamic replanning on demand of UAS constellations performing ISR missions

    NASA Astrophysics Data System (ADS)

    Stouch, Daniel W.; Zeidman, Ernest; Callahan, William; McGraw, Kirk

    2011-05-01

    Unmanned aerial systems (UAS) have proven themselves to be indispensable in providing intelligence, surveillance, and reconnaissance (ISR) over the battlefield. Constellations of heterogeneous, multi-purpose UAS are being tasked to provide ISR in an unpredictable environment. This necessitates the dynamic replanning of critical missions as weather conditions change, new observation targets are identified, aircraft are lost or equipment malfunctions, and new airspace restrictions are introduced. We present a method to generate coordinated mission plans for constellations of UAS with multiple flight goals and potentially competing objectives, and update them on demand as the operational situation changes. We use a fast evolutionary algorithm-based, multi-objective optimization technique. The updated flight routes maintain continuity by considering where the ISR assets have already flown and where they still need to go. Both the initial planning and replanning take into account factors such as area of analysis coverage, restricted operating zones, maximum control station range, adverse weather effects, military terrain value, and sensor performance. Our results demonstrate that by constraining the space of potential solutions using an intelligently-formed air maneuver network with a subset of potential airspace corridors and navigational waypoints, we can ensure global optimization for multiple objectives considering the situation both before and after the replanning is initiated. We employ sophisticated visualization techniques using a geographic information system to help the user 'look under the hood" of the algorithms to understand the effectiveness and viability of the generated ISR mission plans and identify potential gaps in coverage.

  17. The behavioural constellation of deprivation: causes and consequences.

    PubMed

    Pepper, Gillian V; Nettle, Daniel

    2017-01-11

    Socioeconomic differences in behaviour are pervasive and well documented, but their causes are not yet well understood. Here, we make the case that there is a cluster of behaviours associated with lower socioeconomic status, which we call the behavioural constellation of deprivation. We propose that the relatively limited control associated with lower socioeconomic status curtails the extent to which people can expect to realise deferred rewards, leading to more present-oriented behaviour in a range of domains. We illustrate this idea using the specific factor of extrinsic mortality risk, an important factor in evolutionary theoretical models. We emphasise the idea that the present-oriented behaviours of the constellation are a contextually appropriate response to structural and ecological factors, rather than pathology or a failure of willpower. We highlight some principles from evolutionary theoretical models that can deepen our understanding of how socioeconomic inequalities can become amplified and embedded. These principles are that: 1) Small initial disparities can lead to larger eventual inequalities, 2) Feed-back loops can operate to embed early life circumstances, 3) Constraints can breed further constraints, and 4) Feed-back loops can operate over generations. We discuss some of the mechanisms by which socioeconomic status may influence behaviour. We then review how the contextually appropriate response perspective that we have outlined fits with other findings about control and temporal discounting. Finally, we discuss the implications of this interpretation for research and policy.

  18. The BRITE Constellation Nanosatellite Mission: Testing, Commissioning, and Operations

    NASA Astrophysics Data System (ADS)

    Pablo, H.; Whittaker, G. N.; Popowicz, A.; Mochnacki, S. M.; Kuschnig, R.; Grant, C. C.; Moffat, A. F. J.; Rucinski, S. M.; Matthews, J. M.; Schwarzenberg-Czerny, A.; Handler, G.; Weiss, W. W.; Baade, D.; Wade, G. A.; Zocłońska, E.; Ramiaramanantsoa, T.; Unterberger, M.; Zwintz, K.; Pigulski, A.; Rowe, J.; Koudelka, O.; Orleański, P.; Pamyatnykh, A.; Neiner, C.; Wawrzaszek, R.; Marciniszyn, G.; Romano, P.; Woźniak, G.; Zawistowski, T.; Zee, R. E.

    2016-12-01

    BRIght Target Explorer (BRITE) Constellation, the first nanosatellite mission applied to astrophysical research, is a collaboration among Austria, Canada and Poland. The fleet of satellites (6 launched; 5 functioning) performs precise optical photometry of the brightest stars in the night sky. A pioneering mission like BRITE—with optics and instruments restricted to small volume, mass and power in several nanosatellites, whose measurements must be coordinated in orbit—poses many unique challenges. We discuss the technical issues, including problems encountered during on-orbit commissioning (especially higher-than-expected sensitivity of the CCDs to particle radiation). We describe in detail how the BRITE team has mitigated these problems, and provide a complete overview of mission operations. This paper serves as a template for how to effectively plan, build and operate future low-cost niche-driven space astronomy missions. Based on data collected by the BRITE Constellation satellite mission, designed, built, launched, operated and supported by the Austrian Research Promotion Agency (FFG), the University of Vienna, the Technical University of Graz, the Canadian Space Agency (CSA), the University of Toronto Institute for Aerospace Studies (UTIAS), the Foundation for Polish Science & Technology (FNiTP MNiSW), and National Science Centre (NCN).

  19. Surface Landing Site Weather Analysis for NASA's Constellation Program

    NASA Technical Reports Server (NTRS)

    Altino, Karen M.; Burns, K. L.

    2008-01-01

    Weather information is an important asset for NASA's Constellation Program in developing the next generation space transportation system to fly to the International Space Station, the Moon and, eventually, to Mars. Weather conditions can affect vehicle safety and performance during multiple mission phases ranging from pre-launch ground processing of the Ares vehicles to landing and recovery operations, including all potential abort scenarios. Meteorological analysis is art important contributor, not only to the development and verification of system design requirements but also to mission planning and active ground operations. Of particular interest are the surface weather conditions at both nominal and abort landing sites for the manned Orion capsule. Weather parameters such as wind, rain, and fog all play critical roles in the safe landing of the vehicle and subsequent crew and vehicle recovery. The Marshall Space Flight Center (MSFC) Natural Environments Branch has been tasked by the Constellation Program with defining the natural environments at potential landing zones. This paper wiI1 describe the methodology used for data collection and quality control, detail the types of analyses performed, and provide a sample of the results that cab be obtained.

  20. ARGOS: a laser star constellation for the LBT

    NASA Astrophysics Data System (ADS)

    Kanneganti, Shrikrishna; Rabien, Sebastian; Deysenroth, Matthias; Ziegleder, Julian; Gemperlein, Hans; Haug, Marcus

    2010-07-01

    ARGOS is an innovative multi-star adaptive optics system being built for use with LUCIFER on the Large Binocular Telescope (LBT). LUCIFER is a wide field imager and multi-object spectrograph. Using a constellation of laser guide stars permits PSF correction over a wide field in exchange for a relatively small sacrifice in achievable correction. The laser constellation consists of three stars per each of the two eyes of the LBT. The stars are nominally positioned on a circle 2' in radius, but each star can be moved by upto 0.5' in any direction. Nd:YAG (SHG) lasers from InnoLas Laser GmbH are used to create the green (532nm) laser stars, and have an output above 18 W each at the planned pulsing frequency of 10kHz. The lasers are launched using a 40cm telescope and focused at a height of 12 km. The laser system is designed to be optically simple yet configurable. It also provisions for a central sodium laser to be installed later. We detail the characteristics of the laser system and the current state of its development.

  1. Going Beyond Einstein with the Constellation-X Mission

    NASA Technical Reports Server (NTRS)

    White, Nicholas

    2007-01-01

    The Constellation-X mission will address the questions: "What happens to matter close to a black hole?" and "What is Dark Energy?" These questions are central to the NASA Beyond Einstein Program, where Constellation-X plays a central role. The mission will address these questions by using high throughput X-ray spectroscopy to observe the effects of strong gravity close to the event horizon of black holes, and to observe the formation and evolution of clusters of galaxies in order to precisely determine Cosmological parameters. To achieve these primary science goals requires a factor of 25-100 increase in sensitivity for high resolution X-ray spectroscopy.'The mission will also perform routine high-resolution X-ray spectroscopy of faint 2nd extended X-ray source populations. This will provide diagnostic information such as density, elemental abundances, velocity; and ionization state for a wide range of astrophysical problems, including new constraints on the Neutron Star equation of state.

  2. Constellation design and performance analysis for regional satellite navigation system in China area

    NASA Astrophysics Data System (ADS)

    Du, Yuling; Zhang, Xuejun; Huang, Zhigang

    2005-11-01

    Based on the idea of covering China area, a novel constellation is proposed, consisting of one geostationary satellite and five inclined elliptic orbit geosynchronous satellites in this paper. Through a number of simulation tests, the orbital elements of each satellite are designed concretely. Moreover, its coverage performance is also evaluated under some factors, such as the geometric dilution of precision (GDOP), orbital perturbation, space transmission loss and eclipse. What's more, this constellation is compared with other constellations. Finally, Simulation results show, in this constellation, the number of satellites is small, and the navigation precision is relatively high. Therefore, this is a kind of high performance and economic regional navigation system for China.

  3. Constellation Map: Downstream visualization and interpretation of gene set enrichment results.

    PubMed

    Tan, Yan; Wu, Felix; Tamayo, Pablo; Haining, W Nicholas; Mesirov, Jill P

    2015-01-01

    Gene set enrichment analysis (GSEA) approaches are widely used to identify coordinately regulated genes associated with phenotypes of interest. Here, we present Constellation Map, a tool to visualize and interpret the results when enrichment analyses yield a long list of significantly enriched gene sets. Constellation Map identifies commonalities that explain the enrichment of multiple top-scoring gene sets and maps the relationships between them. Constellation Map can help investigators take full advantage of GSEA and facilitates the biological interpretation of enrichment results. Constellation Map is freely available as a GenePattern module at http://www.genepattern.org.

  4. Constellation Map: Downstream visualization and interpretation of gene set enrichment results

    PubMed Central

    Tamayo, Pablo; Haining, W. Nicholas; Mesirov, Jill P.

    2015-01-01

    Summary: Gene set enrichment analysis (GSEA) approaches are widely used to identify coordinately regulated genes associated with phenotypes of interest. Here, we present Constellation Map, a tool to visualize and interpret the results when enrichment analyses yield a long list of significantly enriched gene sets. Constellation Map identifies commonalities that explain the enrichment of multiple top-scoring gene sets and maps the relationships between them. Constellation Map can help investigators take full advantage of GSEA and facilitates the biological interpretation of enrichment results. Availability: Constellation Map is freely available as a GenePattern module at http://www.genepattern.org. PMID:26594333

  5. Ad hoc CubeSat constellations: Secondary launch coverage and distribution

    NASA Astrophysics Data System (ADS)

    Marinan, A.; Nicholas, A.; Cahoy, K.

    The primary purpose of a constellation is to obtain global measurements with improved spatial and temporal resolution. The small size, low cost, standardized form factor, and increasing availability of commercial parts for CubeSats make them ideal for use in constellations. However, without taking advantage of secondary payload opportunities, it would be costly to launch and distribute a CubeSat constellation into a specific configuration. A cost-effective way to launch a constellation of CubeSats is via consecutive secondary payload launch opportunities, but the resulting constellation would be an ad hoc mix of orbit parameters. We focus on the feasibility of cobbling together constellation-like functionality from multiple secondary payload opportunities. Each participating CubeSat (or set of CubeSats) per launch could have completely different orbital parameters, even without propulsion onboard the CubeSats or intermediate transfer carriers. We look at the ground coverages that could be obtained for a constellation of five to six orbital planes with one to six satellites in each plane. We analyze past and announced future launch opportunities for CubeSats, including launch platforms supported by the NASA Educational Launch of Nanosatellites (ELaNa). We consider combinations of possible launch locations and temporal spacings over the course of one year and simulate the resulting ground coverage patterns and revisit times for an ad hoc constellation using these launch opportunities. We perform this analysis for two separate case studies - one with only US launches and one with both US and non-US opportunities - and vary the number of satellites per orbital plane. Typical CubeSat mission lifetimes and deorbit times for low-altitude orbits are included in these analyses. The ad hoc constellation results are compared to coverage from uniformly-placed LEO constellations and are quantified in terms of revisit time, time to 100% global coverage, and response time. For mu

  6. A unique constellation of spacecraft constellations to study KHI in 2017-2020: MMS, Cluster and Themis

    NASA Astrophysics Data System (ADS)

    Masson, Arnaud; Nykyri, Katarina; Escoubet, Philippe; Laakso, Harri

    2017-04-01

    Over more than 10 years, the Cluster and the Themis missions have shed a total new light on the Kelvin-Helmholtz Instability mechanism. To name a few, these missions have enabled the observation of KHI rolled-up vortices for the first with four spacecraft (Hasegawa et al., 2004). They revealed its presence under any IMF conditions (Hwang et al., 2011, 2012), previously underestimated (Kavosi and Raeder, 2015). Very recently, the presence of ion magnetosonic waves with sufficient energy to account for the observed level of ion heating within a KHI vortex may be evidence of cross-scale energy transport (Moore et al., 2016). After presenting some the main highlights of Cluster and Themis on this phenomenon, we will present upcoming new observations with MMS, Cluster and Themis foreseen in 2017-2020 timeframe. Together, they will form a unique constellation of spacecraft constellation to study this phenomenon for the first time. Now looking forward: how to go from a qualitative picture to a quantitative picture of this phenomenon? For instance, how to quantify the role of KHI in the formation of the cold dense plasmasheet? Which observations would be then needed? Two main concepts of new observations will be evoked.

  7. Solar Occultation Constellation for Retrieving Aerosols and Trace Element Species (SOCRATES) Mission Concept

    NASA Astrophysics Data System (ADS)

    Bailey, S. M.; Bevilacqua, R. M.; Fish, C. S.; Gordley, L. L.; Fromm, M. D.

    2014-12-01

    The goal of SOCRATES is to quantify the critical role of the upper troposphere/lower stratosphere (UTLS) in the climate system. The mission would provide, for the first time, the suite of measurements required to quantify stratosphere/troposphere exchange (STE) pathways and their contribution to UTLS composition, and to evaluate the radiative forcing implications of potential changes in STE pathways with climate change. The discrimination and quantification of STE pathways requires simultaneous measurement of several key trace gases and aerosols with high precision, accuracy, and vertical resolution. Furthermore, aerosol and clouds, often present in the UTLS, complicate the measurement of trace gases. The SOCRATES sensor is a 23-channel Gas Filter Correlation Radiometer (GFCR), referred to as GLO (GFCR Limb solar Occultation), with heritage from HALOE on UARS, and SOFIE on AIM. GLO measures aerosol extinction from 0.45 to 3.88 μm, important radiatively active gases in the UTLS (H2O, O3, CH4, N2O), key tracers of STE (HCN, CO, HDO), gases important in stratospheric O3 chemistry (HCl and HF), and temperature from cloud top to 50 km at a vertical resolution of 1 km. Improved pointing knowledge will provide dramatically better retrieval precision in the UTLS, even in the presence of aerosols, than possible with HALOE. In addition, the GLO form factor is only a few percent of that of HALOE, and costs for a constellation of GLO sensors is within the cost cap of a NASA Venture mission. The SOCRATES mission concept is an 8-element constellation of autonomous CubeSats, each mated with a GLO sensor, deployed from a single launch vehicle. The SOCRATES/GLO approach reaps the advantages of solar occultation: high precision and accuracy; robust calibration; and high vertical resolution, while mitigating the sparse coverage of a single solar occultation sensor. We present the SOCRATES science case, and key elements of the SOCRATES mission and GLO instrument concepts.

  8. Solar Occultation Constellation for Retrieving Aerosols and Trace Element Species (SOCRATES): Proposed Mission Concept

    NASA Astrophysics Data System (ADS)

    Gordley, L. L.; Bailey, S. M.

    2015-12-01

    The goal of SOCRATES is to resolve the critical but underexplored role of the upper troposphere/lower stratosphere (UTLS) in climate change. The mission would provide the suite of measurements required to quantify UTLS transport pathways and their contribution to UTLS composition, and to evaluate the radiative forcing implications of changes in UTLS composition forced by expected changes in these pathways as the climate evolves. The discrimination and quantification of UTLS transport pathways requires simultaneous measurement of several key trace gases and aerosols with high precision, accuracy, and vertical resolution. Furthermore, aerosols and clouds, often present in the UTLS, complicate the measurement of trace gases. The SOCRATES sensor is a 23-channel Gas Filter Correlation Radiometer (GFCR), referred to as GLO (GFCR Limb solar Occultation), with heritage from HALOE on UARS, and SOFIE on AIM. GLO measures aerosol extinction from 0.45 to 3.88 μm, important radiatively active gases in the UTLS (H2O, O3, CH4, N2O), key tracers of UTLS transport (HCN, CO, HDO), gases important in stratospheric O3 chemistry (HCl and HF), and temperature from cloud top to 50 km at a vertical resolution of < 1 km. Improved pointing knowledge will provide dramatically better retrieval precision in the UTLS, even in the presence of aerosols, than possible with HALOE. In addition, the GLO form factor is only of order 10% of that of HALOE, and costs for a constellation of GLO sensors is within the cost cap of a NASA Earth Venture mission. The SOCRATES mission concept is a 6-element constellation of autonomous small satellites, each mated with a GLO sensor, and deployed from a single launch vehicle. The SOCRATES/GLO approach reaps the advantages of solar occultation: high precision and accuracy; robust calibration; and high vertical resolution, while mitigating the sparse coverage of a single solar occultation sensor. We present the SOCRATES science case, and key elements of the

  9. Development of a novel constellation based landmark detection algorithm

    NASA Astrophysics Data System (ADS)

    Ghayoor, Ali; Vaidya, Jatin G.; Johnson, Hans J.

    2013-03-01

    Anatomical landmarks such as the anterior commissure (AC) and posterior commissure (PC) are commonly used by researchers for co-registration of images. In this paper, we present a novel, automated approach for landmark detection that combines morphometric constraining and statistical shape models to provide accurate estimation of landmark points. This method is made robust to large rotations in initial head orientation by extracting extra information of the eye centers using a radial Hough transform and exploiting the centroid of head mass (CM) using a novel estimation approach. To evaluate the effectiveness of this method, the algorithm is trained on a set of 20 images with manually selected landmarks, and a test dataset is used to compare the automatically detected against the manually detected landmark locations of the AC, PC, midbrain-pons junction (MPJ), and fourth ventricle notch (VN4). The results show that the proposed method is accurate as the average error between the automatically and manually labeled landmark points is less than 1 mm. Also, the algorithm is highly robust as it was successfully run on a large dataset that included different kinds of images with various orientation, spacing, and origin.

  10. Precipitation from the GPM Microwave Imager and Constellation Radiometers

    NASA Astrophysics Data System (ADS)

    Kummerow, C. D.

    2012-12-01

    Satellite precipitation retrievals are fundamentally underconstrained requiring either implicit or explicit a-prior information to constrain the solutions. The radiometer algorithm being designed for the GPM core and constellation satellites makes this a-priori information explicit in the form of an a-priori database of possible rain structures and a Bayesian retrieval scheme. The a-priori database has its heritage in the TRMM satellite which ushered in an era of active/passive microwave retrievals. Because the output from such retrievals is physically consistent with the rainfall seen by the radar and the brightness temperatures seen by the radiometer, they are ideally suited for the a-priori database. This approach will be repeated for the Global Precipitation Mission, now scheduled for launch in February 2014. Its core satellite will carry a dual frequency radar and state of the art microwave radiometer. This combination of sensors, and the accompanying multi-sensor algorithm will provide a basis for creating the a-priori database for the radiometer only retrievals that is applicable not only to the wider swath of the GPM Microwave Imager (GMI), but to all the constellation radiometers. This talk will present the pre-launch synthesis of various satellite systems to simulate the core satellite retrieval necessary to have a reasonably robust database in place for the launch of the GPM core satellite. The talk will then focus on the implementation of the algorithm itself. This algorithm has a number of advances over previous versions. Most importantly, is the absence of screening routines that previously identified pixels as being raining or non-raining. This was particularly important over land where the surface could easily be mistaken for ice scattering in raining clouds. By having much better controls over the land surface and land surface emissivities, along with robust a-priori databases, the new algorithm relies completely on the Tb signature to determine

  11. Precipitation from the GPM Microwave Imager and Constellation Radiometers

    NASA Astrophysics Data System (ADS)

    Kummerow, Christian; Randel, David; Kirstetter, Pierre-Emmanuel; Kulie, Mark; Wang, Nai-Yu

    2014-05-01

    Satellite precipitation retrievals from microwave sensors are fundamentally underconstrained requiring either implicit or explicit a-priori information to constrain solutions. The radiometer algorithm designed for the GPM core and constellation satellites makes this a-priori information explicit in the form of a database of possible rain structures from the GPM core satellite and a Bayesian retrieval scheme. The a-priori database will eventually come from the GPM core satellite's combined radar/radiometer retrieval algorithm. That product is physically constrained to ensure radiometric consistency between the radars and radiometers and is thus ideally suited to create the a-priori databases for all radiometers in the GPM constellation. Until a robust product exists, however, the a-priori databases are being generated from the combination of existing sources over land and oceans. Over oceans, the Day-1 GPM radiometer algorithm uses the TRMM PR/TMI physically derived hydrometer profiles that are available from the tropics through sea surface temperatures of approximately 285K. For colder sea surface temperatures, the existing profiles are used with lower hydrometeor layers removed to correspond to colder conditions. While not ideal, the results appear to be reasonable placeholders until the full GPM database can be constructed. It is more difficult to construct physically consistent profiles over land due to ambiguities in surface emissivities as well as details of the ice scattering that dominates brightness temperature signatures over land. Over land, the a-priori databases have therefore been constructed by matching satellite overpasses to surface radar data derived from the WSR-88 network over the continental United States through the National Mosaic and Multi-Sensor QPE (NMQ) initiative. Databases are generated as a function of land type (4 categories of increasing vegetation cover as well as 4 categories of increasing snow depth), land surface temperature and

  12. Architecture analysis of the simplified libration point satellite navigation system

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Xu, Bo

    2016-10-01

    The libration point satellite navigation system is a novel navigation architecture that consists of satellites located in periodic orbits around the Earth-Moon libration points. Superiorities of the proposed system lie in its autonomy and extended navigation capability, which have been proved in our previous works. Based on the candidate architectures obtained before, a detailed analysis of the simplified libration point satellite navigation system, i.e. the Earth-Moon L1,2 two-satellite constellation, is conducted in this work. Firstly, relation between orbits amplitude is derived for the candidate two-satellite constellations to ensure continuous crosslink measurements between libration point satellites. Then, with the use of a reference lunar exploration mission scenario, navigation performances of different constellation configurations are evaluated by Monte-Carlo simulations. The simulation results indicate that the amplitude and initial phase combinations of libration point orbits have direct effect on the performance of the two-satellite constellations. By using a cooperative evolutionary algorithm for configuration parameter optimization, some optimal constellations are finally obtained for the simplified navigation architecture. The results obtained in this paper may be a reference for future system design.

  13. High-pressure xenon detector development at Constellation Technology Corporation

    NASA Astrophysics Data System (ADS)

    Austin, Robert A.; Bastian, Lloyd F.

    2006-08-01

    Xenon-filled ionization detectors, due to their high atomic number fill gas (Z=54), moderate densities (~0.3 g/cm 3-0.5 g/cm 3) and good energy resolution (2%-4% at 662 keV), fill an important niche between more familiar technologies such as NaI(Tl) scintillators and Germanium detectors. Until recently, difficulties with obtaining sufficient Xenon purity, reducing microphonic sensitivity, and developing low-noise electronics compatible with small ionization signals have hampered the development of this nuclear detection field. Constellation Technology Corporation, whose experience with xenon detectors goes back to the mid 1990's, has made significant progress in these areas and has developed a commercial line of detectors with active volumes ranging from small (35 g Xe) to large (1400 g Xe). Here we will discuss our development of a mobile, large area, spectroscopic array.

  14. Autonomous Spacecraft Navigation Using Above-the-Constellation GPS Signals

    NASA Technical Reports Server (NTRS)

    Winternitz, Luke

    2017-01-01

    GPS-based spacecraft navigation offers many performance and cost benefits, and GPS receivers are now standard GNC components for LEO missions. Recently, more and more high-altitude missions are taking advantage of the benefits of GPS navigation as well. High-altitude applications pose challenges, however, because receivers operating above the GPS constellations are subject to reduced signal strength and availability, and uncertain signal quality. This presentation will present the history and state-of-the-art in high-altitude GPS spacecraft navigation, including early experiments, current missions and receivers, and efforts to characterize and protect signals available to high-altitude users. Recent results from the very-high altitude MMS mission are also provided.

  15. Uplink Scheduling of Navigation Constellation Based on Immune Genetic Algorithm.

    PubMed

    Tang, Yinyin; Wang, Yueke; Chen, Jianyun; Li, Xianbin

    2016-01-01

    The uplink of navigation data as satellite ephemeris is a complex satellite range scheduling problem. Large-scale optimal problems cannot be tackled using traditional heuristic methods, and the efficiency of standard genetic algorithm is unsatisfactory. We propose a multi-objective immune genetic algorithm (IGA) for uplink scheduling of navigation constellation. The method focuses on balance traffic and maximum task objects based on satellite-ground index encoding method, individual diversity evaluation and memory library. Numerical results show that the multi-hierarchical encoding method can improve the computation efficiency, the fuzzy deviation toleration method can speed up convergence, and the method can achieve the balance target with a negligible loss in task number (approximately 2.98%). The proposed algorithm is a general method and thus can be used in similar problems.

  16. Fault Management Technology Maturation for NASA's Constellation Program

    NASA Technical Reports Server (NTRS)

    Waterman, Robert D.

    2010-01-01

    This slide presentation reviews the maturation of fault management technology in preparation for the Constellation Program. There is a review of the Space Shuttle Main Engine (SSME) and a discussion of a couple of incidents with the shuttle main engine and tanking that indicated the necessity for predictive maintenance. Included is a review of the planned Ares I-X Ground Diagnostic Prototype (GDP) and further information about detection and isolation of faults using Testability Engineering and Maintenance System (TEAMS). Another system that being readied for use that detects anomalies, the Inductive Monitoring System (IMS). The IMS automatically learns how the system behaves and alerts operations it the current behavior is anomalous. The comparison of STS-83 and STS-107 (i.e., the Columbia accident) is shown as an example of the anomaly detection capabilities.

  17. ECLSS and Thermal Systems Integration Challenges Across the Constellation Architecture

    NASA Technical Reports Server (NTRS)

    Carrasquillo, Robyn

    2010-01-01

    As the Constellation Program completes its initial capability Preliminary Design Review milestone for the Initial Capability phase, systems engineering of the Environmental Control and Life Support (ECLS) and Thermal Systems for the various architecture elements has progressed from the requirements to design phase. As designs have matured for the Ares, Orion, Ground Systems, and Extravehicular (EVA) System, a number of integration challenges have arisen requiring analyses and trades, resulting in changes to the design and/or requirements. This paper will address some of the key integration issues and results, including the Orion-to-Ares shared compartment venting and purging, Orion-to-EVA suit loop integration issues with the suit system, Orion-to-ISS and Orion-to-Altair intermodule ventilation, and Orion and Ground Systems impacts from post-landing environments.

  18. Hyperspectral Cubesat Constellation for Rapid Natural Hazard Response

    NASA Technical Reports Server (NTRS)

    Mandl, Daniel; Huemmrich, Karl; Crum, Gary; Ly, Vuong; Handy, Matthew; Ong, Lawrence

    2015-01-01

    Earth Observing 1 (E0-1) satellite has an imaging spectrometer (hyperspectral) instrument called Hyperion. The satellite is able to image any spot on Earth in the nadir looking direction every 16 days. With slewing of the satellite and allowing for up to a 23 degree view angle, any spot on the Earth can be imaged approximately every 2 to 3 days. EO-1 has been used to track many natural hazards such as wildfires, volcanoes and floods. An enhanced capability that is sought is the ability to image natural hazards in a daily time series for space based imaging spectrometers. The Hyperion can not provide this capability on EO-1 with the present polar orbit. However, a constellation of cubesats, each with the same imaging spectrometer, positioned strategically in the same orbit, can be used to provide daily coverage, cost-effectively.

  19. Constellation Program Electrical Ground Support Equipment Research and Development

    NASA Technical Reports Server (NTRS)

    McCoy, Keegan S.

    2010-01-01

    At the Kennedy Space Center, I engaged in the research and development of electrical ground support equipment for NASA's Constellation Program. Timing characteristics playa crucial role in ground support communications. Latency and jitter are two problems that must be understood so that communications are timely and consistent within the Kennedy Ground Control System (KGCS). I conducted latency and jitter tests using Alien-Bradley programmable logic controllers (PLCs) so that these two intrinsic network properties can be reduced. Time stamping and clock synchronization also play significant roles in launch processing and operations. Using RSLogix 5000 project files and Wireshark network protocol analyzing software, I verified master/slave PLC Ethernet module clock synchronization, master/slave IEEE 1588 communications, and time stamping capabilities. All of the timing and synchronization test results are useful in assessing the current KGCS operational level and determining improvements for the future.

  20. Space Technology 5: Pathfinder for Future Micro-Sat Constellations

    NASA Technical Reports Server (NTRS)

    Carlisle, Candace; Finnegan, Eric

    2004-01-01

    The Space Technology 5 (ST-5) Project, currently in the implementation phase, is part of the National Aeronautics and Space Administration (NASA) s New Millennium Program (NMP). ST-5 will consist of a constellation of three miniature satellites, each with mass less than 25 kg and size approximately 60 cm by 30 cm. ST-5 addresses technology challenges, as well as fabrication, assembly, test and operations strategies for future micro-satellite missions. ST-5 will be deployed into a highly eccentric, geo-transfer orbit (GTO). This will expose the spacecraft to a high radiation environment as well as provide a low level magnetic background. A three-month flight demonstration phase is planned to validate the technologies and demonstrate concepts for future missions. Each ST-5 spacecraft incorporates NMP competitively-selected breakthrough technologies. These include Cold Gas Micro-Thrusters for propulsion and attitude control, miniature X-band transponder for space-ground communications, Variable Emittance Coatings for dynamic thermal control, and CULPRiT ultra low power logic chip used for Reed-Solomon encoding. The ST-5 spacecraft itself is a technology that can be infused into future missions. It is a fully functional micro-spacecraft built within tight volume and mass constraints. It is built to withstand a high radiation environment, large thermal variations, and high launch loads. The spacecraft power system is low-power and low-voltage, and is designed to turn on after separation &om the launch vehicle. Some of the innovations that are included in the ST-5 design are a custom spacecraft deployment structure, magnetometer deployment boom, nutation damper, X-band antenna, miniature spinning sun sensor, solar array with triple junction solar cells, integral card cage assembly containing single card Command and Data Handling and Power System Electronics, miniature magnetometer, and lithium ion battery. ST-5 will demonstrate the ability of a micro satellite to perform

  1. The Apollo Experience Lessons Learned for Constellation Lunar Dust Management

    NASA Technical Reports Server (NTRS)

    Wagner, Sandra

    2006-01-01

    Lunar dust will present significant challenges to NASA's Lunar Exploration Missions. The challenges can be overcome by using best practices in system engineering design. For successful lunar surface missions, all systems that come into contact with lunar dust must consider the effects throughout the entire design process. Interfaces between all these systems with other systems also must be considered. Incorporating dust management into Concept of Operations and Requirements development are the best place to begin to mitigate the risks presented by lunar dust. However, that is only the beginning. To be successful, every person who works on NASA's Constellation lunar missions must be mindful of this problem. Success will also require fiscal responsibility. NASA must learn from Apollo the root cause of problems caused by dust, and then find the most cost-effective solutions to address each challenge. This will require a combination of common sense existing technologies and promising, innovative technical solutions

  2. Uplink Scheduling of Navigation Constellation Based on Immune Genetic Algorithm

    PubMed Central

    Tang, Yinyin; Wang, Yueke; Chen, Jianyun; Li, Xianbin

    2016-01-01

    The uplink of navigation data as satellite ephemeris is a complex satellite range scheduling problem. Large–scale optimal problems cannot be tackled using traditional heuristic methods, and the efficiency of standard genetic algorithm is unsatisfactory. We propose a multi-objective immune genetic algorithm (IGA) for uplink scheduling of navigation constellation. The method focuses on balance traffic and maximum task objects based on satellite-ground index encoding method, individual diversity evaluation and memory library. Numerical results show that the multi–hierarchical encoding method can improve the computation efficiency, the fuzzy deviation toleration method can speed up convergence, and the method can achieve the balance target with a negligible loss in task number (approximately 2.98%). The proposed algorithm is a general method and thus can be used in similar problems. PMID:27736986

  3. The Constellation-X Spectroscopy X-Ray Telescope

    NASA Technical Reports Server (NTRS)

    Petre, Robert; Content, David; Lehan, John; O'Dell, Stephen; Owens, Scott; Podgorsky, William; Stewart, Jeff; Zhang, William

    2004-01-01

    The status of technology development for the Constellation-X Spectroscopy X-ray Telescope (SXT) mirror is presented. The SXT mirror combines a large (1.6 m) aperture with modest (12 arc sec half power diameter) angular resolution and low mass (750 kg). The overall collecting area, larger than 9,600 square cm at 0.25 keV, requires high throughput, and thus nesting of a substantial number of thin reflectors. A phased development program is underway to develop reflectors, mounting and alignment approaches, and metrology techniques for components and the mirror has a whole. The latest results in all these areas are summarized, along with an overview of results of optical testing of reflector performance.

  4. Waste Collector System Technology Comparisons for Constellation Applications

    NASA Technical Reports Server (NTRS)

    Broyan, James Lee, Jr.

    2006-01-01

    The Waste Collection Systems (WCS) for space vehicles have utilized a variety of hardware for collecting human metabolic wastes. It has typically required multiple missions to resolve crew usability and hardware performance issues that are difficult to duplicate on the ground. New space vehicles should leverage off past WCS systems. Past WCS hardware designs are substantially different and unique for each vehicle. However, each WCS can be analyzed and compared as a subset of technologies which encompass fecal collection, urine collection, air systems, pretreatment systems. Technology components from the WCS of various vehicles can then be combined to reduce hardware mass and volume while maximizing use of previous technology and proven human-equipment interfaces. Analysis of past US and Russian WCS are compared and extrapolated to Constellation missions.

  5. Constellation Stick Figures Convey Information about Gravity and Neutrinos

    NASA Astrophysics Data System (ADS)

    Mc Leod, David Matthew; Mc Leod, Roger David

    2008-10-01

    12/21/98, at America's Stonehenge, DMM detected, and drew, the full stick-figure equivalent of Canis Major, CM, as depicted by our Wolf Clan leaders, and many others. Profound, foundational physics is implied, since this occurred in the Watch House there, hours before the ``model rose.'' Similar configurations like Orion, Osiris of ancient Egypt, show that such figures are projected through solid parts of the Earth, as two-dimensional equivalents of the three-dimensional star constellations. Such ``sticks'' indicate that ``line equivalents'' connect the stars, and the physical mechanism projects outlines detectable by traditional cultures. We had discussed this ``flashlight'' effect, and recognized some of its implications. RDM states that the flashlight is a strong, distant neutrino source; the lines represent neutrinos longitudinally aligned in gravitational excitation, opaque, to earthbound, transient, transversely excited neutrinos. ``Sticks'' represent ``graviton'' detection. Neutrinos' longitudinal alignment accounts for the weakness of gravitational force.

  6. Connecting the Sun and Earth: Field ALigned Connections Constellation

    NASA Astrophysics Data System (ADS)

    Stoneback, R.

    2016-12-01

    As the solar wind flows past the Earth power flows along geomagnetic field lines into the Earth's ionosphere, driving high latitude convection and plasma motions throughout the magnetosphere. Complete understanding of this energy flux has been limited by the availability of measurements. The presented Field ALigned CONnections constellation concept is designed to measure the energy flux as well as the energy deposited into the polar ionosphere. In collaboration with the ground based SuperDARN, measurements from both platforms may be assimilated into a cohesive system to better understand energy flow. The assimilation of DMSP and SuperDARN high-latitude convection measurements using Data Interpolating Empirical Orthogonal Functions (DINEOFs) will be shown.

  7. The Apollo Expericence Lessons Learned for Constellation Lunar Dust Management

    NASA Astrophysics Data System (ADS)

    Wagner, Sandra

    2006-09-01

    Lunar dust will present significant challenges to NASA's Lunar Exploration Missions. The challenges can be overcome by using best practices in system engineering design. For successful lunar surface missions, all systems that come into contact with lunar dust must consider the effects throughout the entire design process. Interfaces between all these systems with other systems also must be considered. Incorporating dust management into Concept of Operations and Requirements development are the best place to begin to mitigate the risks presented by lunar dust. However, that is only the beginning. To be successful, every person who works on NASA's Constellation lunar missions must be mindful of this problem. Success will also require fiscal responsibility. NASA must learn from Apollo the root cause of problems caused by dust, and then find the most cost-effective solutions to address each challenge. This will require a combination of common sense existing technologies and promising, innovative technical solutions

  8. Constellation Program Mission Operations Project Office Status and Support Philosophy

    NASA Technical Reports Server (NTRS)

    Smith, Ernest; Webb, Dennis

    2007-01-01

    The Constellation Program Mission Operations Project Office (CxP MOP) at Johnson Space Center in Houston Texas is preparing to support the CxP mission operations objectives for the CEV/Orion flights, the Lunar Lander, and and Lunar surface operations. Initially the CEV will provide access to the International Space Station, then progress to the Lunar missions. Initial CEV mission operations support will be conceptually similar to the Apollo missions, and we have set a challenge to support the CEV mission with 50% of the mission operations support currently required for Shuttle missions. Therefore, we are assessing more efficient way to organize the support and new technologies which will enhance our operations support. This paper will address the status of our preparation for these CxP missions, our philosophical approach to CxP operations support, and some of the technologies we are assessing to streamline our mission operations infrastructure.

  9. Scale analysis of equatorial plasma irregularities derived from Swarm constellation

    NASA Astrophysics Data System (ADS)

    Xiong, Chao; Stolle, Claudia; Lühr, Hermann; Park, Jaeheung; Fejer, Bela G.; Kervalishvili, Guram N.

    2016-07-01

    In this study, we investigated the scale sizes of equatorial plasma irregularities (EPIs) using measurements from the Swarm satellites during its early mission and final constellation phases. We found that with longitudinal separation between Swarm satellites larger than 0.4°, no significant correlation was found any more. This result suggests that EPI structures include plasma density scale sizes less than 44 km in the zonal direction. During the Swarm earlier mission phase, clearly better EPI correlations are obtained in the northern hemisphere, implying more fragmented irregularities in the southern hemisphere where the ambient magnetic field is low. The previously reported inverted-C shell structure of EPIs is generally confirmed by the Swarm observations in the northern hemisphere, but with various tilt angles. From the Swarm spacecrafts with zonal separations of about 150 km, we conclude that larger zonal scale sizes of irregularities exist during the early evening hours (around 1900 LT).

  10. SAC-C Mission and the Morning Constellation

    NASA Astrophysics Data System (ADS)

    Colomb, F. R.; Alonso, C.; Hofmann, C.; Frulla, L.; Nollmann, I.; Milovich, J.; Kuba, J.; Ares, F.; Kalemkarian, M.

    2002-01-01

    components (ICARE), provided by CNES will permit improvement of risk estimation models for radiation effect on last generation integrated circuit technology. . On June 14th, 2000 CONAE and NASA signed an amendment to the Memorandum of Understanding for the SAC-C mission in order that the SAC-C satellite, were included in a constellation - named "Morning Constellation". It is integrated by USA satellites Landsat 7, EO 1, Terra, and Argentine SAC-C that feature on-board instruments from the United States, Argentina, Denmark, Italy, France, and Japan. The four satellite tracks on the Earth's surface are the same, their orbital height being 705 km and their inclination, 98.21 degrees. They cross the Equator at 10:00, 10:01, 10:15, and 10:30 hours, respectively (local time). Satellites comply with the World Wide Reference System. The Constellation has been working since March 2001 as a single mission and several cooperative activities have been undertaken and will be presented in this paper. Several jointly sponsored technical workshops have been held, and also collaborative spacecraft navigation experiments have been made. One of the objectives of the AM Constellation is the collaboration in the case of emergencies, NASA and CONAE agreed to give preference in those situation in the planification of their satellite acquisitions. From all the possible hazardous events, the most important for the country are fire and floods. In relation to fires, CONAE is presently adapting and developing the algorithms for using MODIS data to generate a fire map product. Additionally research on fire detection is carried out using the data from the HSTC camera. In relation to flooding, CONAE works in cooperation to national institutions providing the data and, in some cases, producing flood extent maps. In particular MMRS data is demonstrating to be very effective due to its spectral and radiometric resolutions, and its large swath which is well suited for extended countries like Argentina.

  11. LAMOST 1: A Disrupted Satellite in the Constellation Draco

    NASA Astrophysics Data System (ADS)

    Vickers, John J.; Smith, Martin C.; Hou, Yonghui; Wang, Yuefei; Zhang, Yong

    2016-01-01

    Using Large Sky Area Multi-object Fibre Spectroscopic Telescope spectroscopic data, we find a strong signal of a comoving group of stars in the constellation of Draco. The group, observed near the apocenter of its orbit, is 2.6 kpc from the Sun with a metallicity of -0.64 dex. The system is observed as a streaming population of unknown provenance with mass of about 2.1+/- 0.4\\cdot {10}4 {M}⊙ and brightness of about {M}V˜ -3.6. Its high metallicity, diffuse physical structure, and eccentric orbit may indicate that the progenitor satellite was a globular cluster rather than a dwarf galaxy or an open cluster.

  12. Space Technology 5: Pathfinder for Future Micro-Sat Constellations

    NASA Technical Reports Server (NTRS)

    Carlisle, Candace; Finnegan, Eric

    2004-01-01

    The Space Technology 5 (ST-5) Project, currently in the implementation phase, is part of the National Aeronautics and Space Administration (NASA) s New Millennium Program (NMP). ST-5 will consist of a constellation of three miniature satellites, each with mass less than 25 kg and size approximately 60 cm by 30 cm. ST-5 addresses technology challenges, as well as fabrication, assembly, test and operations strategies for future micro-satellite missions. ST-5 will be deployed into a highly eccentric, geo-transfer orbit (GTO). This will expose the spacecraft to a high radiation environment as well as provide a low level magnetic background. A three-month flight demonstration phase is planned to validate the technologies and demonstrate concepts for future missions. Each ST-5 spacecraft incorporates NMP competitively-selected breakthrough technologies. These include Cold Gas Micro-Thrusters for propulsion and attitude control, miniature X-band transponder for space-ground communications, Variable Emittance Coatings for dynamic thermal control, and CULPRiT ultra low power logic chip used for Reed-Solomon encoding. The ST-5 spacecraft itself is a technology that can be infused into future missions. It is a fully functional micro-spacecraft built within tight volume and mass constraints. It is built to withstand a high radiation environment, large thermal variations, and high launch loads. The spacecraft power system is low-power and low-voltage, and is designed to turn on after separation &om the launch vehicle. Some of the innovations that are included in the ST-5 design are a custom spacecraft deployment structure, magnetometer deployment boom, nutation damper, X-band antenna, miniature spinning sun sensor, solar array with triple junction solar cells, integral card cage assembly containing single card Command and Data Handling and Power System Electronics, miniature magnetometer, and lithium ion battery. ST-5 will demonstrate the ability of a micro satellite to perform

  13. Spacecraft autonomy using onboard processing for a SAR constellation mission

    NASA Technical Reports Server (NTRS)

    Sherwood, R. L.; Chien, S.; Castano, R.; Rabideau, G.

    2002-01-01

    The Autonomous Sciencecraft Experiment (ASE) will fly onboard the Air Force TechSat 21 constellation of three spacecraft scheduled for launch in 2006. ASE uses onboard continuous planning, robust task and goal-based execution, model-based mode identification and reconfiguration, and onboard machine learning and pattern recognition to radically increase science return by enabling intelligent downlink selection and autonomous retargeting. In this paper we discuss how these AI technologies are synergistically integrated in a hybrid multi-layer control architecture to enable a virtual spacecruft science agent. Demonstration of these capabilities in a flight environment will open up tremendous new opportunities in planetary science, space physics, and earth science that would be unreachable without this technology.

  14. Constellation Program Mission Operations Project Office Status and Support Philosophy

    NASA Technical Reports Server (NTRS)

    Smith, Ernest; Webb, Dennis

    2007-01-01

    The Constellation Program Mission Operations Project Office (CxP MOP) at Johnson Space Center in Houston Texas is preparing to support the CxP mission operations objectives for the CEV/Orion flights, the Lunar Lander, and and Lunar surface operations. Initially the CEV will provide access to the International Space Station, then progress to the Lunar missions. Initial CEV mission operations support will be conceptually similar to the Apollo missions, and we have set a challenge to support the CEV mission with 50% of the mission operations support currently required for Shuttle missions. Therefore, we are assessing more efficient way to organize the support and new technologies which will enhance our operations support. This paper will address the status of our preparation for these CxP missions, our philosophical approach to CxP operations support, and some of the technologies we are assessing to streamline our mission operations infrastructure.

  15. CATIA V5 Virtual Environment Support for Constellation Ground Operations

    NASA Technical Reports Server (NTRS)

    Kelley, Andrew

    2009-01-01

    This summer internship primarily involved using CATIA V5 modeling software to design and model parts to support ground operations for the Constellation program. I learned several new CATIA features, including the Imagine and Shape workbench and the Tubing Design workbench, and presented brief workbench lessons to my co-workers. Most modeling tasks involved visualizing design options for Launch Pad 39B operations, including Mobile Launcher Platform (MLP) access and internal access to the Ares I rocket. Other ground support equipment, including a hydrazine servicing cart, a mobile fuel vapor scrubber, a hypergolic propellant tank cart, and a SCAPE (Self Contained Atmospheric Protective Ensemble) suit, was created to aid in the visualization of pad operations.

  16. Tabitha's One Teacher Rural School: Insights into the Arts through the Use of a Story Constellation

    ERIC Educational Resources Information Center

    Garvis, Susanne

    2011-01-01

    This paper presents a story constellation about a beginning teacher (who is also the principal) located in a one-teacher school in an isolated community in Queensland, Australia. The constellation documents the teacher's self-efficacy for teaching the arts (music, dance, drama, visual arts and media). Tabitha, the participant, shares insights…

  17. Story Constellations: A Narrative Approach to Contextualizing Teachers' Knowledge of School Reform

    ERIC Educational Resources Information Center

    Craig, Cheryl J.

    2007-01-01

    This article traces the roots of narrative research in the social sciences and education, then centers on "story constellations," a version of narrative inquiry that uncovers teachers' knowledge of school reform in context. A fluid form of investigation that unfolds in a three-dimensional inquiry space, story constellations consists of a flexible…

  18. Story Constellations: A Narrative Approach to Contextualizing Teachers' Knowledge of School Reform

    ERIC Educational Resources Information Center

    Craig, Cheryl J.

    2007-01-01

    This article traces the roots of narrative research in the social sciences and education, then centers on "story constellations," a version of narrative inquiry that uncovers teachers' knowledge of school reform in context. A fluid form of investigation that unfolds in a three-dimensional inquiry space, story constellations consists of a flexible…

  19. Constellation's First Flight Test: Ares I-X

    NASA Technical Reports Server (NTRS)

    Davis, Stephan R.; Askins, Bruce R.

    2010-01-01

    On October 28, 2009, NASA launched Ares I-X, the first flight test of the Constellation Program that will send human beings to the Moon and beyond. This successful test is the culmination of a three-and-a-half-year, multi-center effort to design, build, and fly the first demonstration vehicle of the Ares I crew launch vehicle, the successor vehicle to the Space Shuttle. The suborbital mission was designed to evaluate the atmospheric flight characteristics of a vehicle dynamically similar to Ares I; perform a first stage separation and evaluate its effects; characterize and control roll torque; stack, fly, and recover a solid-motor first stage testing the Ares I parachutes; characterize ground, flight, and reentry environments; and develop and execute new ground hardware and procedures. Built from existing flight and new simulator hardware, Ares I-X integrated a Shuttle-heritage four-segment solid rocket booster for first stage propulsion, a spacer segment to simulate a five-segment booster, Peacekeeper axial engines for roll control, and Atlas V avionics, as well as simulators for the upper stage, crew module, and launch abort system. The mission leveraged existing logistical and ground support equipment while also developing new ones to accommodate the first in-line rocket for flying astronauts since the Saturn IB last flew from Kennedy Space Center (KSC) in 1975. This paper will describe the development and integration of the various vehicle and ground elements, from conception to stacking in KSC s Vehicle Assembly Building; hardware performance prior to, during, and after the launch; and preliminary lessons and data gathered from the flight. While the Constellation Program is currently under review, Ares I-X has and will continue to provide vital lessons for NASA personnel in taking a vehicle concept from design to flight.

  20. Advanced Lithium-Ion Cell Development for NASA's Constellation Missions

    NASA Technical Reports Server (NTRS)

    Reid, Concha M.; Miller, Thomas B.; Manzo, Michelle A.; Mercer, Carolyn R.

    2008-01-01

    The Energy Storage Project of NASA s Exploration Technology Development Program is developing advanced lithium-ion batteries to meet the requirements for specific Constellation missions. NASA GRC, in conjunction with JPL and JSC, is leading efforts to develop High Energy and Ultra High Energy cells for three primary Constellation customers: Altair, Extravehicular Activities (EVA), and Lunar Surface Systems. The objective of the High Energy cell development is to enable a battery system that can operationally deliver approximately 150 Wh/kg for 2000 cycles. The Ultra High Energy cell development will enable a battery system that can operationally deliver 220 Wh/kg for 200 cycles. To accomplish these goals, cathode, electrolyte, separator, and safety components are being developed for High Energy Cells. The Ultra High Energy cell development adds lithium alloy anodes to the component development portfolio to enable much higher cell-level specific energy. The Ultra High Energy cell development is targeted for the ascent stage of Altair, which is the Lunar Lander, and for power for the Portable Life support System of the EVA Lunar spacesuit. For these missions, mass is highly critical, but only a limited number of cycles are required. The High Energy cell development is primarily targeted for Mobility Systems (rovers) for Lunar Surface Systems, however, due to the high risk nature of the Ultra High Energy cell development, the High Energy cell will also serve as a backup technology for Altair and EVA. This paper will discuss mission requirements and the goals of the material, component, and cell development efforts in further detail.

  1. Surface Landing Site Weather Analysis for Constellation Program

    NASA Technical Reports Server (NTRS)

    Altino, Karen M.; Burns, K. Lee

    2008-01-01

    Weather information is an important asset for NASA's Constellation Program in developing the next generation space transportation system to fly to the International Space Station, the Moon and, eventually, to Mars. Weather conditions can affect vehicle safety and performance during multiple mission phases ranging from pre-launch ground processing to landing and recovery operations, including all potential abort scenarios. Meteorological analysis is an important contributor, not only to the development and verification of system design requirements but also to mission planning and active ground operations. Of particular interest are the surface atmospheric conditions at both nominal and abort landing sites for the manned Orion capsule. Weather parameters such as wind, rain, and fog all play critical roles in the safe landing of the vehicle and subsequent crew and vehicle recovery. The Marshall Space Flight Center Natural Environments Branch has been tasked by the Constellation Program with defining the natural environments at potential landing zones. Climatological time series of operational surface weather observations are used to calculate probabilities of occurrence of various sets of hypothetical vehicle constraint thresholds, Data are available for numerous geographical locations such that statistical analysis can be performed for single sites as well as multiple-site network configurations. Results provide statistical descriptions of how often certain weather conditions are observed at the site(s) and the percentage that specified criteria thresholds are matched or exceeded. Outputs are tabulated by month and hour of day to show both seasonal and diurnal variation. This paper will describe the methodology used for data collection and quality control, detail the types of analyses performed, and provide a sample of the results that can be obtained,

  2. The NASA CYGNSS Satellite Constellation for Tropical Cyclone Observations

    NASA Astrophysics Data System (ADS)

    Ruf, C. S.; Provost, D.; Rose, R.; Scherrer, J.; Atlas, R. M.; Chang, P.; Clarizia, M. P.; Garrison, J. L.; Gleason, S.; Katzberg, S. J.; Jelenak, Z.; Johnson, J. T.; Majumdar, S.; O'Brien, A.; Posselt, D. J.; Ridley, A. J.; Said, F.; Soisuvarn, S.; Zavorotny, V. U.

    2016-12-01

    The NASA Cyclone Global Navigation Satellite System (CYGNSS) is scheduled for launch in November 2016 to study the surface wind structure in and near the inner core of tropical cyclones. CYGNSS consists of a constellation of eight observatories carried into orbit on a single launch vehicle. Each observatory carries a 4-channel bistatic radar receiver tuned to receive GPS navigation signals scattered from the ocean surface. The eight satellites are spaced approximately twelve minutes apart in a common circular, low inclination orbit plane to provide frequent temporal sampling in the tropics. The 35deg orbit inclination results in coverage of the full globe between 38deg N and 38deg S latitude with a median(mean) revisit time of 3(7) hours The 32 CYGNSS radars operate in L-Band at a wavelength of 19 cm. This allows for adequate penetration to enable surface wind observations under all levels of precipitation, including those encountered in the inner core and eyewall of tropical cyclones. The combination of operation unaffected by heavy precipitation together with high temporal resolution throughout the life cycle of storms is expected to support significant improvements in the forecast skill of storm track and intensity, as well as better situational awareness of the extent and structure of storms in near real time. A summary of the properties of the CYGNSS science data products will be presented, together with an update on the results of ongoing Observation System Simulation Experiments performed by members of the CYGNSS science team over the past four years, in particular addressing the expected impact on storm track and intensity forecast skill. With launch scheduled for the month prior to AGU, the on orbit status of the constellation will also be presented.

  3. 41 CFR 302-9.104 - What may I do if there is no port or terminal at the point of origin and/or destination?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the segment of travel from the port of embarkation back to your authorized origin after delivering the... will be reimbursed your one-way transportation cost. The total cost of round-trip travel, to deliver... diem allowance for round-trip travel to and from the port involved. POV Transportation at Time...

  4. 41 CFR 302-9.104 - What may I do if there is no port or terminal at the point of origin and/or destination?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... destination. For the segment of travel from the port of embarkation back to your authorized origin after... POV, you will be reimbursed your one-way transportation cost. The total cost of round-trip travel, to... diem allowance for round-trip travel to and from the port involved. POV Transportation at Time...

  5. 41 CFR 302-9.104 - What may I do if there is no port or terminal at the point of origin and/or destination?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... the segment of travel from the port of embarkation back to your authorized origin after delivering the... will be reimbursed your one-way transportation cost. The total cost of round-trip travel, to deliver... diem allowance for round-trip travel to and from the port involved. POV Transportation at Time...

  6. 41 CFR 302-9.104 - What may I do if there is no port or terminal at the point of origin and/or destination?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... destination. For the segment of travel from the port of embarkation back to your authorized origin after... POV, you will be reimbursed your one-way transportation cost. The total cost of round-trip travel, to... diem allowance for round-trip travel to and from the port involved. POV Transportation at Time...

  7. 41 CFR 302-9.104 - What may I do if there is no port or terminal at the point of origin and/or destination?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... destination. For the segment of travel from the port of embarkation back to your authorized origin after... POV, you will be reimbursed your one-way transportation cost. The total cost of round-trip travel, to... diem allowance for round-trip travel to and from the port involved. POV Transportation at Time...

  8. 41 CFR 302-7.7 - May the origin and destination points be other than that prescribed in § 302-7.6?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Property Management Federal Travel Regulation System RELOCATION ALLOWANCES TRANSPORTATION AND STORAGE OF PROPERTY 7-TRANSPORTATION AND TEMPORARY STORAGE OF HOUSEHOLD GOODS AND PROFESSIONAL BOOKS, PAPERS, AND... reimbursement is limited to the cost of transporting the property in one lot from the authorized origin to...

  9. 41 CFR 302-7.7 - May the origin and destination points be other than that prescribed in § 302-7.6?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Property Management Federal Travel Regulation System RELOCATION ALLOWANCES TRANSPORTATION AND STORAGE OF PROPERTY 7-TRANSPORTATION AND TEMPORARY STORAGE OF HOUSEHOLD GOODS AND PROFESSIONAL BOOKS, PAPERS, AND... reimbursement is limited to the cost of transporting the property in one lot from the authorized origin to...

  10. 41 CFR 302-7.7 - May the origin and destination points be other than that prescribed in § 302-7.6?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Property Management Federal Travel Regulation System RELOCATION ALLOWANCES TRANSPORTATION AND STORAGE OF PROPERTY 7-TRANSPORTATION AND TEMPORARY STORAGE OF HOUSEHOLD GOODS AND PROFESSIONAL BOOKS, PAPERS, AND... reimbursement is limited to the cost of transporting the property in one lot from the authorized origin to...

  11. Optical channel de-aggregation of quadrature-phase-shift-keying and eight-phase-shift-keying data using mapping onto constellation axes.

    PubMed

    Ziyadi, Morteza; Mohajerin-Ariaei, Amirhossein; Almaiman, Ahmed; Cao, Yinwen; Chitgarha, Mohammad Reza; Paraschis, Loukas; Tur, Moshe; Langrock, Carsten; Fejer, Martin M; Touch, Joseph D; Willner, Alan E

    2015-11-01

    An eight-phase-shift-keying signal is experimentally de-aggregated onto two four-pulse amplitude modulation signals using nonlinear processes in optical elements. Quadrature-phase-shift-keying signals are similarly de-multiplexed into two binary phase shift keying signals by mapping the data points onto the constellation axes. De-multiplexing performance is evaluated as a function of the optical signal-to-noise ratio of the incoming signals. The effect of phase noise is also studied.

  12. Learning the Constellations: From Junior High to Undergraduate Descriptive Astronomy Class

    NASA Astrophysics Data System (ADS)

    Stephens, Denise C.; Hintz, Eric G.; Hintz, Maureen; Lawler, Jeannette; Jones, Michael; Bench, Nathan

    2015-01-01

    As part of two separate studies we have examined the ability of students to learn and remember a group of constellations, bright stars, and deep sky objects. For a group of junior high students we tested their knowledge of only the constellations by giving them a 'constellation quiz' without any instruction. We then provided the students with a lab session, and retested. We also tested a large number of undergraduate students in our descriptive astronomy classes, but in this case there were the same 30 constellations, 17 bright stars, and 3 deep sky objects. The undergraduate students were tested in a number of ways: 1) pre-testing without instruction, 2) self-reporting of knowledge, 3) normal constellation quizzes as part of the class, and 4) retesting students from previous semesters. This provided us with a set of baseline measurements, allowed us to track the learning curve, and test retention of the material. We will present our early analysis of the data.

  13. Typology of person-environment fit constellations: a platform addressing accessibility problems in the built environment for people with functional limitations.

    PubMed

    Slaug, Björn; Schilling, Oliver; Iwarsson, Susanne; Carlsson, Gunilla

    2015-09-02

    Making the built environment accessible for all regardless of functional capacity is an important goal for public health efforts. Considerable impediments to achieving this goal suggest the need for valid measurements of acccessibility and for greater attention to the complexity of person-environment fit issues. To address these needs, this study aimed to provide a methodological platform, useful for further research and instrument development within accessibility research. This was accomplished by the construction of a typology of problematic person-environment fit constellations, utilizing an existing methodology developed to assess and analyze accessibility problems in the built environment. By means of qualitative review and statistical methods we classified the person-environment fit components covered by an existing application which targets housing accessibility: the Housing Enabler (HE) instrument. The International Classification of Functioning, Disability and Health (ICF) was used as a conceptual framework. Qualitative classification principles were based on conceptual similarities and for quantitative analysis of similarities, Principal Component Analysis was carried out. We present a typology of problematic person-environment fit constellations classified along three dimensions: 1) accessibility problem range and severity 2) aspects of functioning 3) environmental context. As a result of the classification of the HE components, 48 typical person-environment fit constellations were recognised. The main contribution of this study is the proposed typology of person-environment fit constellations. The typology provides a methodological platform for the identification and quantification of problematic person-environment fit constellations. Its link to the globally accepted ICF classification system facilitates communication within the scientific and health care practice communities. The typology also highlights how relations between aspects of functioning

  14. A possible space VLBI constellation utilizing the stable orbits around the TLPs in the Earth-Moon system.

    NASA Astrophysics Data System (ADS)

    Liu, Bin; Tang, Jingshi; Hou, Xiyun

    2016-07-01

    Current studies indicate that there are stable orbits around but far away from the triangular libration points .Two special quasi-periodic orbits around each triangular libration points L4 , L5 in the Earth-Moon sys-tem perturbed by Sun are gain , and the stable orbits discussed in this work are ideal places for space colonies because no orbit control is needed. These stable orbits can also be used as nominal orbits for space VLBI (Very Long Baseline Interferometry) stations. The two stations can also form baselines with stations on the Earth and the Moon, or with stations located around another TLP. Due to the long distance between the stations, the observation precision can be greatly enhanced compared with the VLBI stations on the Earth. Such a VLBI constellation not only can advance the radio astronomy, but also can be used as a navigation system for human activities in the Earth-Moon system and even in the solar system. This paper will focus on the navigation constellation coverage issues, and the orbit determination accuracy problems within the Earth-Moon sys-tem and interplanetary space.

  15. Sequence similarities of the capsid gene of Chilean and European isolates of infectious pancreatic necrosis virus point towards a common origin.

    PubMed

    Mutoloki, Stephen; Evensen, Øystein

    2011-07-01

    The Chilean salmonid industry was developed by importing breeding materials, a practice still in effect due to deficits in the national supply of roe. Importation of breeding materials is often associated with the transmission of pathogens. The objectives of this study were to compare the infectious pancreatic necrosis virus (IPNV) isolates from Chile to those of European origin and to determine the diversity of the Chilean IPNV. The VP2 genes of IPNV from Chilean fish (whose eggs originated from Scotland, Iceland and Norway) were compared to isolates from fish in Norway and Ireland. The results show that the isolates are identical (97-99%) and cluster into one genogroup. Our findings support previous reports of association between the trade-in breeding materials and transmission of pathogens. Furthermore, our results demonstrate the genotypic diversity of Chilean IPNV isolates. These findings have important implications for IPNV disease diagnosis and control in Chile.

  16. Array of Neutral Density Relative Observations MEasuring Divergence in the Atmosphere (ANDROMEDA), A Constellation Concept for Studying Thermospheric Dynamics

    NASA Astrophysics Data System (ADS)

    Palo, S. E.; Pilinski, M.; Forbes, J. M.

    2015-12-01

    In addition to being critical to the prediction of satellite orbits, total mass density is a fundamental property of the thermosphere. Density measurements from accelerometers on the CHAMP satellite have revealed quasi-steady state distributions of density structures around the globe, density responses to changing solar and geomagnetic activity, and spatial structures of wave-like phenomena along the orbit. However, a basic limitation on the time scale of any observable phenomenon is the ~90-minute orbital period. Thus, single-satellite missions like CHAMP are unable to measure the time derivative of density or the mass flux divergence (MFD) at a single point in the atmosphere. While the two accelerometer-carrying GRACE satellites could theoretically measure the density time derivative, in practice this measurement is hampered by the very low-signal levels in the tenuous atmosphere at the ~500-km GRACE orbits, as well as inter-satellite biases and drifts. The Array of Neutral Density Relative Observations Measuring Divergence in the Atmosphere (ANDROMEDA) is a constellation of CubeSats aimed at improving our understanding of atmospheric dynamics by measuring and interpreting the characteristics of traveling atmospheric disturbances as well as the distribution of MFD in the thermosphere. The ANDROMEDA constellation consists of two to three identical CubeSats spaced approximately 300 km apart and making multi-point measurements of total mass density with an accuracy of <2%. The mass density measurements will be made using a novel torque balance technique enabled by an extremely accurate attitude determination and control system (ADCS) that actively compensates for atmospheric disturbance torques. The benefit of the torque-balance technique is the high level of inter-satellite accuracy. The constellation will be deployed from the ISS and will make observations between 400 km and 250 km altitude as the satellite orbits decay. Distance between the spacecraft will be

  17. Cubesat-Based Dtv Receiver Constellation for Ionospheric Tomography

    NASA Astrophysics Data System (ADS)

    Bahcivan, H.; Leveque, K.; Doe, R. A.

    2013-12-01

    The Radio Aurora Explorer mission, funded by NSF's Space Weather and Atmospheric Research program, has demonstrated the utility of CubeSat-based radio receiver payloads for ionospheric research. RAX has primarily been an investigation of microphysics of meter-scale ionospheric structures; however, the data products are also suitable for research on ionospheric effects on radio propagation. To date, the spacecraft has acquired (1) ground-based UHF radar signals that are backscattered from meter-scale ionospheric irregularities, which have been used to measure the dispersion properties of meter-scale plasma waves and (2) ground-based signals, directly on the transmitter-spacecraft path, which have been used to measure radio propagation disturbances (scintillations). Herein we describe the application of a CubeSat constellation of UHF receivers to expand the latter research topic for global-scale ionospheric tomography. The enabling factor for this expansion is the worldwide availability of ground-based digital television (DTV) broadcast signals whose characteristics are optimal for scintillation analysis. A significant part of the populated world have transitioned, or soon to be transitioned, to DTV. The DTV signal has a standard format that contains a highly phase-stable pilot carrier that can be readily adapted for propagation diagnostics. A multi-frequency software-defined radar receiver, similar to the RAX payload, can measure these signals at a large number of pilot carrier frequencies to make radio ray and diffraction tomographic measurements of the ionosphere and the irregularities contained in it. A constellation of CubeSats, launched simultaneously, or in sequence over years, similar to DMSPs, can listen to the DTV stations, providing a vast and dense probing of the ionosphere. Each spacecraft can establish links to a preprogrammed list of DTV stations and cycle through them using time-division frequency multiplexing (TDFM) method. An on board program can

  18. 77 FR 11169 - In the Matter of Exelon Corporation; Constellation Energy Group, Inc.; R.E. Ginna Nuclear Power...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-24

    ... License] In the Matter of Exelon Corporation; Constellation Energy Group, Inc.; R.E. Ginna Nuclear Power... (Exelon), and Exelon Ventures Company, LLC (Exelon Ventures), and Constellation Energy Nuclear Group, LLC...'s parent companies, Constellation Energy Group, Inc. (CEG), whereby CEG would be merged into...

  19. Rare ADH Variant Constellations are Specific for Alcohol Dependence

    PubMed Central

    Zuo, Lingjun; Zhang, Heping; Malison, Robert T.; Li, Chiang-Shan R.; Zhang, Xiang-Yang; Wang, Fei; Lu, Lingeng; Lu, Lin; Wang, Xiaoping; Krystal, John H.; Zhang, Fengyu; Deng, Hong-Wen; Luo, Xingguang

    2013-01-01

    Aims: Some of the well-known functional alcohol dehydrogenase (ADH) gene variants (e.g. ADH1B*2, ADH1B*3 and ADH1C*2) that significantly affect the risk of alcohol dependence are rare variants in most populations. In the present study, we comprehensively examined the associations between rare ADH variants [minor allele frequency (MAF) <0.05] and alcohol dependence, with several other neuropsychiatric and neurological disorders as reference. Methods: A total of 49,358 subjects in 22 independent cohorts with 11 different neuropsychiatric and neurological disorders were analyzed, including 3 cohorts with alcohol dependence. The entire ADH gene cluster (ADH7–ADH1C–ADH1B–ADH1A–ADH6–ADH4–ADH5 at Chr4) was imputed in all samples using the same reference panels that included whole-genome sequencing data. We stringently cleaned the phenotype and genotype data to obtain a total of 870 single nucleotide polymorphisms with 0< MAF <0.05 for association analysis. Results: We found that a rare variant constellation across the entire ADH gene cluster was significantly associated with alcohol dependence in European-Americans (Fp1: simulated global P = 0.045), European-Australians (Fp5: global P = 0.027; collapsing: P = 0.038) and African-Americans (Fp5: global P = 0.050; collapsing: P = 0.038), but not with any other neuropsychiatric disease. Association signals in this region came principally from ADH6, ADH7, ADH1B and ADH1C. In particular, a rare ADH6 variant constellation showed a replicable association with alcohol dependence across these three independent cohorts. No individual rare variants were statistically significantly associated with any disease examined after group- and region-wide correction for multiple comparisons. Conclusion: We conclude that rare ADH variants are specific for alcohol dependence. The ADH gene cluster may harbor a causal variant(s) for alcohol dependence. PMID:23019235

  20. Breath-giving cooperation: critical review of origin of mitochondria hypotheses : Major unanswered questions point to the importance of early ecology.

    PubMed

    Zachar, István; Szathmáry, Eörs

    2017-08-14

    The origin of mitochondria is a unique and hard evolutionary problem, embedded within the origin of eukaryotes. The puzzle is challenging due to the egalitarian nature of the transition where lower-level units took over energy metabolism. Contending theories widely disagree on ancestral partners, initial conditions and unfolding of events. There are many open questions but there is no comparative examination of hypotheses. We have specified twelve questions about the observable facts and hidden processes leading to the establishment of the endosymbiont that a valid hypothesis must address. We have objectively compared contending hypotheses under these questions to find the most plausible course of events and to draw insight on missing pieces of the puzzle. Since endosymbiosis borders evolution and ecology, and since a realistic theory has to comply with both domains' constraints, the conclusion is that the most important aspect to clarify is the initial ecological relationship of partners. Metabolic benefits are largely irrelevant at this initial phase, where ecological costs could be more disruptive. There is no single theory capable of answering all questions indicating a severe lack of ecological considerations. A new theory, compliant with recent phylogenomic results, should adhere to these criteria. This article was reviewed by Michael W. Gray, William F. Martin and Purificación López-García.

  1. Transgressive origin of channeled estuarine deposits in the Point Lookout Sandstone, northwestern New Mexico: A model for Upper Cretaceous, cyclic regressive parasequences of the US Western Interior

    SciTech Connect

    Devine, P.E. )

    1991-06-01

    Regionally correlatable regressions, recorded in Upper Cretaceous strata from the US Western Interior, represent low-order cyclic progradations of the epeiric seaway shoreline. Stratigraphic intertonguing of coastal sandstone deposits and marine shales developed in response to higher order depositional cycles where episodic transgressions interrupt regressions. A simple model based on Walther's Law of Facies has most often been used to interpret these deposits, including channeled estuarine sandstones commonly found at the top of the sequence. The author proposes an alternative explanation for these deposits based on time-stratigraphic architecture and component facies distributions of the Point Lookout Sandstone in the northwestern San Juan basin, New Mexico. Interpretations of outcrop measured sections and well-log correlations suggest an individual parasequence is actually the product of a depositional couplet that includes a regressive phase and a transgressive phase. Strand-plain progradation during the regressive phase produced upward-coarsening, shoreline deposits. Deposition during the transgressive phase occurred mainly in a zone landward of a reworked shoreline trend and comprises a lagoonal-estuarine system. Transgressive estuarine deposits appear to be an important potential reservoir facies in the Point Lookout section. Each estuarine sandstone is developed as a discrete reservoir unit at the landward limit of a parasequence. These sandstones can be correlated into the subsurface and their distribution mapped parallel to depositional strike. The distribution of channeled estuarine reservoirs can be predicted and effectively exploited based on the depositional couplet mode.

  2. From value chain to value constellation: designing interactive strategy.

    PubMed

    Normann, R; Ramírez, R

    1993-01-01

    In today's fast-changing competitive environment, strategy is no longer a matter of positioning a fixed set of activities along that old industrial model, the value chain. Successful companies increasingly do not just add value, they reinvent it. The key strategic task is to reconfigure roles and relationships among a constellation of actors--suppliers, partners, customers--in order to mobilize the creation of value by new combinations of players. What is so different about this new logic of value? It breaks down the distinction between products and services and combines them into activity-based "offerings" from which customers can create value for themselves. But as potential offerings grow more complex, so do the relationships necessary to create them. As a result, a company's strategic task becomes the ongoing reconfiguration and integration of its competencies and customers. The authors provide three illustrations of these new rules of strategy. IKEA has blossomed into the world's largest retailer of home furnishings by redefining the relationships and organizational practices of the furniture business. Danish pharmacies and their national association have used the opportunity of health care reform to reconfigure their relationships with customers, doctors, hospitals, drug manufacturers, and with Danish and international health organizations to enlarge their role, competencies, and profits. French public-service concessionaires have mastered the art of conducting a creative dialogue between their customers--local governments in France and around the world--and a perpetually expanding set of infrastructure competencies.

  3. Nucleotide sequence conservation in paramyxoviruses; the concept of codon constellation.

    PubMed

    Rima, Bert K

    2015-05-01

    The stability and conservation of the sequences of RNA viruses in the field and the high error rates measured in vitro are paradoxical. The field stability indicates that there are very strong selective constraints on sequence diversity. The nature of these constraints is discussed. Apart from constraints on variation in cis-acting RNA and the amino acid sequences of viral proteins, there are other ones relating to the presence of specific dinucleotides such CpG and UpA as well as the importance of RNA secondary structures and RNA degradation rates. Recent other constraints identified in other RNA viruses, such as effects of secondary RNA structure on protein folding or modification of cellular tRNA complements, are also discussed. Using the family Paramyxoviridae, I show that the codon usage pattern (CUP) is (i) specific for each virus species and (ii) that it is markedly different from the host - it does not vary even in vaccine viruses that have been derived by passage in a number of inappropriate host cells. The CUP might thus be an additional constraint on variation, and I propose the concept of codon constellation to indicate the informational content of the sequences of RNA molecules relating not only to stability and structure but also to the efficiency of translation of a viral mRNA resulting from the CUP and the numbers and position of rare codons.

  4. Lunar Natural Environment for use by the Constellation Program

    NASA Technical Reports Server (NTRS)

    Ferguson, Dale C.

    2009-01-01

    The Lunar Environments used by the Constellation Program are embodied in two documents, the NEDD (Natural Environments Definition for Design) and the DSNE (Design Specification for Natural Environments). Recently, the lunar environments for the NEDD have been defined and incorporated in the document, as the result of contributions from experts in all areas of lunar environments. The purpose of the NEDD is to provide a uniform description of the natural environment to serve as a basic framework for both the crewed and robotic missions of the Exploration Systems Mission Directorate (ESMD). It is intended to support engineering and analysis, requirements development, and verification involved in the development of exploration concepts and architectures, flight hardware, and new technologies. (It does not support the operational phases of the Program since models and data with different properties are needed for those applications.) By presenting a single benchmark definition of natural environment parameters it provides an easily accessible and uniform baseline for competitive studies, independent analyses, and concept studies.

  5. Visibility and Geometry of Global Satellite Navigation Systems Constellations

    NASA Astrophysics Data System (ADS)

    Januszewski, Jacek

    2015-12-01

    Nowadays (November 2015) there are two global fully operational satellite navigation systems, American GPS and Russian GLONASS. Two next are under construction, Galileo in Europe and BeiDou in China. As the error of observer's position obtained from these systems depends on geometry factor DOP (Dilution Of Precision) among other things the knowledge of the number of satellites visible by this observer above given masking elevation angle Hmin and the distributions of DOP coefficient values, GDOP in particular, is very important. The lowest and the greatest number of satellites visible in open area by the observer at different latitudes for different Hmin, the percentage of satellites visible above angle H (9 intervals, each 10O wide), distributions (in per cent) of satellites azimuths (8 intervals, each 45O wide) and GDOP coefficient values (8 intervals) for Hmin = 5O for all these four systems at different observer's latitudes (9 intervals, each wide 10O wide) are presented in the paper. Additionally the lowest elevation for which the number of satellites visible at different latitudes by the observer in open area above this angle is equal 4 or 3 and the distributions (in per cent) of GDOP coefficient values for different Hmin at observer's latitudes 50-60O for the same four systems are showed. All calculations were made for constellation of GPS 27 satellites, GLONASS 24, Galileo 30 and BeiDou 27 MEO satellites.

  6. Vega-Constellation Tools to Analize Hyperspectral Images

    NASA Astrophysics Data System (ADS)

    Savorskiy, V.; Loupian, E.; Balashov, I.; Kashnitskii, A.; Konstantinova, A.; Tolpin, V.; Uvarov, I.; Kuznetsov, O.; Maklakov, S.; Panova, O.; Savchenko, E.

    2016-06-01

    Creating high-performance means to manage massive hyperspectral data (HSD) arrays is an actual challenge when it is implemented to deal with disparate information resources. Aiming to solve this problem the present work develops tools to work with HSD in a distributed information infrastructure, i.e. primarily to use those tools in remote access mode. The main feature of presented approach is in the development of remotely accessed services, which allow users both to conduct search and retrieval procedures on HSD sets and to provide target users with tools to analyze and to process HSD in remote mode. These services were implemented within VEGA-Constellation family information systems that were extended by adding tools oriented to support the studies of certain classes of natural objects by exploring their HSD. Particular developed tools provide capabilities to conduct analysis of such objects as vegetation canopies (forest and agriculture), open soils, forest fires, and areas of thermal anomalies. Developed software tools were successfully tested on Hyperion data sets.

  7. "The Reflection Grating Spectrometer on Constellation-X"

    NASA Technical Reports Server (NTRS)

    Cottam, J.

    2006-01-01

    The Constellation-X Reflection Grating Spectrometer (RGS) is designed to provide high-throughput, high-resolution spectra in the long wavelength band of 6 to 50 angstrom. In the nominal design an array of reflection gratings is mounted at the exit of the Spectroscopy X-ray Telescope (SXT) mirror module. The gratings intercept and disperse light to a designated array of CCD detectors. To achieve the throughput (A_eff > 1000 cm2 below 0.6 keV) and resolution (R > 300 below 0.6 keV) requirements for the instrument we are investigating two possible grating designs. The first design uses in-plane gratings in a classical configuration that is very similar to the XMM-Newton RGS. The second design uses off-plane gratings in a conical configuration. The off-plane design has the advantage of providing higher reflectivity and potentially, a higher spectral resolution than the in-plane configuration. In our presentation we will describe the performance requirements and the current status of the technology development.

  8. Efficient mission control for the 48-satellite Globalstar Constellation

    NASA Technical Reports Server (NTRS)

    Smith, Dan

    1994-01-01

    The Globalstar system is being developed by Globalstar, Limited Partnership and will utilize 48 satellites in low earth orbit (See Figure 1) to create a world-wide mobile communications system consistent with Vice President Gore's vision of a Global Information Infrastructure. As a large long term commercial system developed by a newly formed organization, Globalstar provides an excellent opportunity to explore innovative solutions for highly efficient satellite command and control. Design and operational concepts being developed are unencumbered by existing physical and organizational infrastructures. This program really is 'starting with a clean sheet of paper'. Globalstar operations challenges can appear enormous. Clearly, assigning even a single person around the clock to monitor and control each satellite is excessive for Globalstar (it would require a staff of 200! . Even with only a single contact per orbit per satellite, data acquisitions will start or stop every 45 seconds! Although essentially identical, over time the satellites will develop their own 'personalities'and will re quire different data calibrations and levels of support. This paper discusses the Globalstar system and challenges and presents engineering concepts, system design decisions, and operations concepts which address the combined needs and concerns of satellite, ground system, and operations teams. Lessons from past missions have been applied, organizational barriers broken, partnerships formed across the mission segments, and new operations concepts developed for satellite constellation management. Control center requirements were then developed from the operations concepts.

  9. "The Reflection Grating Spectrometer on Constellation-X"

    NASA Technical Reports Server (NTRS)

    Cottam, J.

    2006-01-01

    The Constellation-X Reflection Grating Spectrometer (RGS) is designed to provide high-throughput, high-resolution spectra in the long wavelength band of 6 to 50 angstrom. In the nominal design an array of reflection gratings is mounted at the exit of the Spectroscopy X-ray Telescope (SXT) mirror module. The gratings intercept and disperse light to a designated array of CCD detectors. To achieve the throughput (A_eff > 1000 cm2 below 0.6 keV) and resolution (R > 300 below 0.6 keV) requirements for the instrument we are investigating two possible grating designs. The first design uses in-plane gratings in a classical configuration that is very similar to the XMM-Newton RGS. The second design uses off-plane gratings in a conical configuration. The off-plane design has the advantage of providing higher reflectivity and potentially, a higher spectral resolution than the in-plane configuration. In our presentation we will describe the performance requirements and the current status of the technology development.

  10. Development of Mirror Segments for the Constellation-X Observatory

    NASA Technical Reports Server (NTRS)

    Zhang, W.; Content, David; Henderson, Stephen; Petre, Robert; Saha, Timo

    2003-01-01

    As NASA's next major X-ray observatory, Constellation-X will have a photon collection area of 30,000 sq cm at 1 keV, which, after folding other instrumental responses, translates into an effective area of 15,000 sq cm. The observatory consists of four identical satellites each of which carries a spectroscopic X-ray telescope mirror assembly (SXT) that is 1.6 m in diameter and has a focal length of 10 m and a collection area of 7,500 sq cm at 1 keV and an angular resolution of 15 sec. HPD (half-power diameter) at the system level. Each mirror assembly consists of a large number of mirror segments precisely assembled together. Our development of the mirror segments is divided into two steps. The first one is to develop the basic approach and fabricate segments within the constraints of existing infrastructure to meet the angular resolution requirement, but not mirror segment size requirement. We have all but successfully completed this part of the development. We are now on the verge of going into the second step, that is to fabricate mirror segments of larger sizes to reduce the number of segments that have to be aligned and integrated. In this paper, we report on the requirements and the development status of the mirror segments. These assembly and other requirements of the SXT are reported elsewhere.

  11. Cell assemblies at multiple time scales with arbitrary lag constellations

    PubMed Central

    Russo, Eleonora; Durstewitz, Daniel

    2017-01-01

    Hebb's idea of a cell assembly as the fundamental unit of neural information processing has dominated neuroscience like no other theoretical concept within the past 60 years. A range of different physiological phenomena, from precisely synchronized spiking to broadly simultaneous rate increases, has been subsumed under this term. Yet progress in this area is hampered by the lack of statistical tools that would enable to extract assemblies with arbitrary constellations of time lags, and at multiple temporal scales, partly due to the severe computational burden. Here we present such a unifying methodological and conceptual framework which detects assembly structure at many different time scales, levels of precision, and with arbitrary internal organization. Applying this methodology to multiple single unit recordings from various cortical areas, we find that there is no universal cortical coding scheme, but that assembly structure and precision significantly depends on the brain area recorded and ongoing task demands. DOI: http://dx.doi.org/10.7554/eLife.19428.001 PMID:28074777

  12. Earth's Radiation Imbalance from a Constellation of 66 Iridium Satellites

    NASA Astrophysics Data System (ADS)

    Chiu, J. C.; Wiscombe, W. J.

    2012-04-01

    The Earth Radiation Imbalance (ERI) at the top of the atmosphere is the primary driving force for climate change. If ERI is not zero, then Earth's temperature, both oceanic and atmospheric, will change gradually over time, tending toward a new steady state. The best estimates of current ERI from climate models range from 0.4 to 0.9 W/m2 (the imbalance being caused mainly by increasing CO2), but current satellite systems do not have the accuracy to measure ERI to even one significant digit. In this paper, we will describe a proposed constellation of 66 Earth radiation budget instruments, to be hosted on Iridium satellites. This system represents a quantum leap over current systems in several ways, in particular in providing ERI to at least one significant digit, thus enabling a crucial test of climate models. Because of its 24/7 coverage, the system will also provide ERI at three-hourly time scales without requiring extrapolations from narrowband geostationary instruments. This would allow studies of ERI's response to fast-evolving phenomena like dust storms and hurricanes. This offers a new, synoptic view of Earth radiation budget that will transform it from a monthly average into a dynamical variable alongside standard meteorological variables like temperature and pressure.

  13. The Rorschach Suicide Constellation: assessing various degrees of lethality.

    PubMed

    Fowler, J C; Piers, C; Hilsenroth, M J; Holdwick, D J; Padawer, J R

    2001-04-01

    In this article we examine the relation between the Rorschach Comprehensive System's Suicide Constellation (S-CON; Exner, 1993; Exner & Wiley, 1977) and lethality of suicide attempts during the course of patients' hospitalization at the Austen Riggs Center (Stockbridge, MA). Patient records were rated as nonsuicidal (n = 37), parasuicidal (n = 37), or near-lethal (n = 30) based on the presence and lethality of self-destructive acts. Diagnostic efficiency statistics utilizing a cutoff score of 7 or more positive indicators successfully predicted which patients would engage in near-lethal suicidal activity relative to parasuicidal patients (overall correct classification rate [OCC] = .79), nonsuicidal inpatients (OCC = .79), and college students (OCC = .89). Although these predictions were influenced by relatively high base rates in the hospital population (14.5%), base rate estimates were calculated for other hypothetical populations revealing different prediction estimates that should be considered when judging the relative efficacy of the S-CON. Logistic regression analysis revealed that an S-CON score of 7 or more was the sole predictor of near-lethal suicide attempts among 9 psychiatric and demographic variables.

  14. Point Source All Sky

    NASA Image and Video Library

    2003-03-27

    This panoramic view encompasses the entire sky as seen by Two Micron All-Sky Survey. The measured brightnesses of half a billion stars (points) have been combined into colors representing three distinct wavelengths of infrared light: blue at 1.2 microns, green at 1.6 microns, and red at 2.2 microns. This image is centered on the core of our own Milky Way galaxy, toward the constellation of Sagittarius. The reddish stars seemingly hovering in the middle of the Milky Way's disc -- many of them never observed before -- trace the densest dust clouds in our galaxy. The two faint smudges seen in the lower right quadrant are our neighboring galaxies, the Small and Large Magellanic Clouds. http://photojournal.jpl.nasa.gov/catalog/PIA04250

  15. Point Source All Sky

    NASA Technical Reports Server (NTRS)

    2003-01-01

    This panoramic view encompasses the entire sky as seen by Two Micron All-Sky Survey. The measured brightnesses of half a billion stars (points) have been combined into colors representing three distinct wavelengths of infrared light: blue at 1.2 microns, green at 1.6 microns, and red at 2.2 microns. This image is centered on the core of our own Milky Way galaxy, toward the constellation of Sagittarius. The reddish stars seemingly hovering in the middle of the Milky Way's disc -- many of them never observed before -- trace the densest dust clouds in our galaxy. The two faint smudges seen in the lower right quadrant are our neighboring galaxies, the Small and Large Magellanic Clouds.

  16. An Approach to Speed up Single-Frequency PPP Convergence with Quad-Constellation GNSS and GIM.

    PubMed

    Cai, Changsheng; Gong, Yangzhao; Gao, Yang; Kuang, Cuilin

    2017-06-06

    The single-frequency precise point positioning (PPP) technique has attracted increasing attention due to its high accuracy and low cost. However, a very long convergence time, normally a few hours, is required in order to achieve a positioning accuracy level of a few centimeters. In this study, an approach is proposed to accelerate the single-frequency PPP convergence by combining quad-constellation global navigation satellite system (GNSS) and global ionospheric map (GIM) data. In this proposed approach, the GPS, GLONASS, BeiDou, and Galileo observations are directly used in an uncombined observation model and as a result the ionospheric and hardware delay (IHD) can be estimated together as a single unknown parameter. The IHD values acquired from the GIM product and the multi-GNSS differential code bias (DCB) product are then utilized as pseudo-observables of the IHD parameter in the observation model. A time varying weight scheme has also been proposed for the pseudo-observables to gradually decrease its contribution to the position solutions during the convergence period. To evaluate the proposed approach, datasets from twelve Multi-GNSS Experiment (MGEX) stations on seven consecutive days are processed and analyzed. The numerical results indicate that the single-frequency PPP with quad-constellation GNSS and GIM data are able to reduce the convergence time by 56%, 47%, 41% in the east, north, and up directions compared to the GPS-only single-frequency PPP.

  17. An Approach to Speed up Single-Frequency PPP Convergence with Quad-Constellation GNSS and GIM

    PubMed Central

    Cai, Changsheng; Gong, Yangzhao; Gao, Yang; Kuang, Cuilin

    2017-01-01

    The single-frequency precise point positioning (PPP) technique has attracted increasing attention due to its high accuracy and low cost. However, a very long convergence time, normally a few hours, is required in order to achieve a positioning accuracy level of a few centimeters. In this study, an approach is proposed to accelerate the single-frequency PPP convergence by combining quad-constellation global navigation satellite system (GNSS) and global ionospheric map (GIM) data. In this proposed approach, the GPS, GLONASS, BeiDou, and Galileo observations are directly used in an uncombined observation model and as a result the ionospheric and hardware delay (IHD) can be estimated together as a single unknown parameter. The IHD values acquired from the GIM product and the multi-GNSS differential code bias (DCB) product are then utilized as pseudo-observables of the IHD parameter in the observation model. A time varying weight scheme has also been proposed for the pseudo-observables to gradually decrease its contribution to the position solutions during the convergence period. To evaluate the proposed approach, datasets from twelve Multi-GNSS Experiment (MGEX) stations on seven consecutive days are processed and analyzed. The numerical results indicate that the single-frequency PPP with quad-constellation GNSS and GIM data are able to reduce the convergence time by 56%, 47%, 41% in the east, north, and up directions compared to the GPS-only single-frequency PPP. PMID:28587305

  18. A novel modelling framework to prioritize estimation of non-point source pollution parameters for quantifying pollutant origin and discharge in urban catchments.

    PubMed

    Fraga, I; Charters, F J; O'Sullivan, A D; Cochrane, T A

    2016-02-01

    Stormwater runoff in urban catchments contains heavy metals (zinc, copper, lead) and suspended solids (TSS) which can substantially degrade urban waterways. To identify these pollutant sources and quantify their loads the MEDUSA (Modelled Estimates of Discharges for Urban Stormwater Assessments) modelling framework was developed. The model quantifies pollutant build-up and wash-off from individual impervious roof, road and car park surfaces for individual rain events, incorporating differences in pollutant dynamics between surface types and rainfall characteristics. This requires delineating all impervious surfaces and their material types, the drainage network, rainfall characteristics and coefficients for the pollutant dynamics equations. An example application of the model to a small urban catchment demonstrates how the model can be used to identify the magnitude of pollutant loads, their spatial origin and the response of the catchment to changes in specific rainfall characteristics. A sensitivity analysis then identifies the key parameters influencing each pollutant load within the stormwater given the catchment characteristics, which allows development of a targeted calibration process that will enhance the certainty of the model outputs, while minimizing the data collection required for effective calibration. A detailed explanation of the modelling framework and pre-calibration sensitivity analysis is presented.

  19. Identification of promiscuous ene-reductase activity by mining structural databases using active site constellations

    PubMed Central

    Steinkellner, Georg; Gruber, Christian C.; Pavkov-Keller, Tea; Binter, Alexandra; Steiner, Kerstin; Winkler, Christoph; Łyskowski, Andrzej; Schwamberger, Orsolya; Oberer, Monika; Schwab, Helmut; Faber, Kurt; Macheroux, Peter; Gruber, Karl

    2014-01-01

    The exploitation of catalytic promiscuity and the application of de novo design have recently opened the access to novel, non-natural enzymatic activities. Here we describe a structural bioinformatic method for predicting catalytic activities of enzymes based on three-dimensional constellations of functional groups in active sites (‘catalophores’). As a proof-of-concept we identify two enzymes with predicted promiscuous ene-reductase activity (reduction of activated C–C double bonds) and compare them with known ene-reductases, that is, members of the Old Yellow Enzyme family. Despite completely different amino acid sequences, overall structures and protein folds, high-resolution crystal structures reveal equivalent binding modes of typical Old Yellow Enzyme substrates and ligands. Biochemical and biocatalytic data show that the two enzymes indeed possess ene-reductase activity and reveal an inverted stereopreference compared with Old Yellow Enzymes for some substrates. This method could thus be a tool for the identification of viable starting points for the development and engineering of novel biocatalysts. PMID:24954722

  20. Methodology and method and apparatus for signaling with capacity optimized constellations

    NASA Technical Reports Server (NTRS)

    Barsoum, Maged F. (Inventor); Jones, Christopher R. (Inventor)

    2011-01-01

    Communication systems having transmitter, includes a coder configured to receive user bits and output encoded bits at an expanded output encoded bit rate, a mapper configured to map encoded bits to symbols in a symbol constellation, a modulator configured to generate a signal for transmission via the communication channel using symbols generated by the mapper. In addition, the receiver includes a demodulator configured to demodulate the received signal via the communication channel, a demapper configured to estimate likelihoods from the demodulated signal, a decoder that is configured to estimate decoded bits from the likelihoods generated by the demapper. Furthermore, the symbol constellation is a capacity optimized geometrically spaced symbol constellation that provides a given capacity at a reduced signal-to-noise ratio compared to a signal constellation that maximizes d.sub.min.