Science.gov

Sample records for original constellation points

  1. Origins of the "Western" Constellations

    NASA Astrophysics Data System (ADS)

    Frank, Roslyn M.

    The development of the 48 Greek constellations is analyzed as a complex mixture of cognitive layers deriving from different cultural traditions and dating back to different epochs. The analysis begins with a discussion of the zodiacal constellations, goes on to discuss the stellar lore in Homer and Hesiod, and then examines several theories concerning the origins of the southern non-zodiacal constellations. It concludes with a commentary concerning the age and possible cultural significance of stars of the Great Bear constellation in light of ethnohistorical documentation, folklore, and beliefs related to European bear ceremonialism.

  2. The origin of the constellations

    NASA Astrophysics Data System (ADS)

    Roy, Archie E.

    The problem of the origin of the stellar constellations familiar to western astronomers from ancient times is discussed in an attempt to answer the classical detective story questions: Who? When? Why? and Where? The available astronomical, literary and archaeological evidence is examined to suggest a possible solution.

  3. The Origin of Our Constellations.

    ERIC Educational Resources Information Center

    Ridpath, Ian

    1990-01-01

    Reviewed is the history of the naming of the constellations which appear in the sky. The roles of many ancient peoples through the astronomers of the eighteenth century up to the adoption of the official list of 88 constellations produced in 1922 by the International Astronomical Union are discussed. (CW)

  4. 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.

  5. 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.

  6. 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

  7. Code Single Point Positioning Using Nominal GNSS Constellations (Future Perception)

    NASA Astrophysics Data System (ADS)

    Farah, A. M. A.

    Global Navigation Satellite Systems (GNSS) have an endless number of applications in industry, science, military, transportation and recreation & sports. Two systems are currently in operation, namely GPS (the USA Global Positioning System) and GLONASS (the Russian GLObal NAvigation Satellite System), and a third is planned, the European satellite navigation system GALILEO. The potential performance improvements achievable through combining these systems could be significant and expectations are high. The need is inevitable to explore the future of positioning from different nominal constellations. In this research paper, Bernese 5.0 software could be modified to simulate and process GNSS observations from three different constellations (GPS, GLONASS and Galileo) using different combinations. This study presents results of code single point positioning for five stations using the three constellations and different combinations.

  8. 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.

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

    PubMed

    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

  10. 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

  11. 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.

  12. Precise point positioning with quad-constellations: GPS, BeiDou, GLONASS and Galileo

    NASA Astrophysics Data System (ADS)

    Cai, Changsheng; Gao, Yang; Pan, Lin; Zhu, Jianjun

    2015-07-01

    Multi-constellation GNSS precise point positioning (PPP) first became feasible back to 2007 but with only two constellations, namely GPS and GLONASS. With the availability of more satellites and precise orbit and clock products from BeiDou and Galileo, it is possible now to investigate PPP with four constellations, namely GPS, BeiDou, GLONASS and Galileo. This research aims at investigating the quad-constellation PPP for position determination and analyzing its positioning performance. A quad-constellation PPP model is developed to simultaneously process the observations from all the four GNSS systems. The developed model is also applicable to the PPP processing with observations from single, dual or triple constellations. The analysis on PPP accuracy and convergence time is conducted based on data processing results from both static and kinematic tests of single-constellation and multi-constellations. The three-hour static positioning results indicate that the BeiDou-only PPP accuracy is worse than the GPS-only PPP. The RMSs of position errors for BeiDou-only PPP are 5.2 cm, 2.7 cm and 8.3 cm in east, north and up directions while the ones for GPS-only PPP are 3.9 cm, 1.6 cm and 5.7 cm. The GPS/BeiDou PPP improves the positioning accuracy by 28%, 6% and 7% and reduces the convergence time by 26%, 13% and 14% over the GPS-only PPP in three coordinate components, respectively. The GPS/GLONASS PPP achieves slightly better performance than the GPS/BeiDou PPP. The triple-constellation PPP further increases the positioning accuracy and decreases the convergence time over the dual-constellation PPP. The improvement of positioning performance is not significant after adding Galileo due to currently limited number of satellites. Similar to the static positioning, the quad-constellation kinematic PPP also significantly improves the positioning performance in contrast with single-constellation and dual-constellations. The time varying characteristics of the time differences

  13. 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.

  14. On biases in precise point positioning with multi-constellation and multi-frequency GNSS data

    NASA Astrophysics Data System (ADS)

    El-Mowafy, A.; Deo, M.; Rizos, C.

    2016-03-01

    Various types of biases in Global Navigation Satellite System (GNSS) data preclude integer ambiguity fixing and degrade solution accuracy when not being corrected during precise point positioning (PPP). In this contribution, these biases are first reviewed, including satellite and receiver hardware biases, differential code biases, differential phase biases, initial fractional phase biases, inter-system receiver time biases, and system time scale offset. PPP models that take account of these biases are presented for two cases using ionosphere-free observations. The first case is when using primary signals that are used to generate precise orbits and clock corrections. The second case applies when using additional signals to the primary ones. In both cases, measurements from single and multiple constellations are addressed. It is suggested that the satellite-related code biases be handled as calibrated quantities that are obtained from multi-GNSS experiment products and the fractional phase cycle biases obtained from a network to allow for integer ambiguity fixing. Some receiver-related biases are removed using between-satellite single differencing, whereas other receiver biases such as inter-system biases are lumped with differential code and phase biases and need to be estimated. The testing results show that the treatment of biases significantly improves solution convergence in the float ambiguity PPP mode, and leads to ambiguity-fixed PPP within a few minutes with a small improvement in solution precision.

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

    DOEpatents

    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.

  16. Accuracy improvement techniques in Precise Point Positioning method using multiple GNSS constellations

    NASA Astrophysics Data System (ADS)

    Vasileios Psychas, Dimitrios; Delikaraoglou, Demitris

    2016-04-01

    The future Global Navigation Satellite Systems (GNSS), including modernized GPS, GLONASS, Galileo and BeiDou, offer three or more signal carriers for civilian use and much more redundant observables. The additional frequencies can significantly improve the capabilities of the traditional geodetic techniques based on GPS signals at two frequencies, especially with regard to the availability, accuracy, interoperability and integrity of high-precision GNSS applications. Furthermore, highly redundant measurements can allow for robust simultaneous estimation of static or mobile user states including more parameters such as real-time tropospheric biases and more reliable ambiguity resolution estimates. This paper presents an investigation and analysis of accuracy improvement techniques in the Precise Point Positioning (PPP) method using signals from the fully operational (GPS and GLONASS), as well as the emerging (Galileo and BeiDou) GNSS systems. The main aim was to determine the improvement in both the positioning accuracy achieved and the time convergence it takes to achieve geodetic-level (10 cm or less) accuracy. To this end, freely available observation data from the recent Multi-GNSS Experiment (MGEX) of the International GNSS Service, as well as the open source program RTKLIB were used. Following a brief background of the PPP technique and the scope of MGEX, the paper outlines the various observational scenarios that were used in order to test various data processing aspects of PPP solutions with multi-frequency, multi-constellation GNSS systems. Results from the processing of multi-GNSS observation data from selected permanent MGEX stations are presented and useful conclusions and recommendations for further research are drawn. As shown, data fusion from GPS, GLONASS, Galileo and BeiDou systems is becoming increasingly significant nowadays resulting in a position accuracy increase (mostly in the less favorable East direction) and a large reduction of convergence

  17. 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....

  18. 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.

  19. 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…

  20. Origins of the human pointing gesture: a training study.

    PubMed

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

    2012-11-01

    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 musical activities. One hundred and two infants of 9, 10, or 11 months of age were seen at the beginning, middle, and end of this one-month period and tested for declarative pointing and gaze following. Infants'ability to point with the index finger at the end of the study was not affected by the training but was instead predicted by infants' prior ability to follow the gaze direction of an adult. The frequency with which infants pointed indexically was also affected by infant gaze following ability and, in addition, by maternal pointing frequency in free play, but not by training. In contrast, infants' ability to monitor their partner's gaze when pointing, and the frequency with which they did so, was affected by both training and maternal pointing frequency in free play. These results suggest that prior social cognitive advances, rather than adult socialization of pointing per se, determine the developmental onset of indexical pointing, but socialization processes such as imitation and adult shaping subsequently affect both infants' ability to monitor their interlocutor's gaze while they point and how frequently infants choose to point. PMID:23106736

  1. 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.

  2. Constellation Coverage Analysis

    NASA Technical Reports Server (NTRS)

    Lo, Martin W. (Compiler)

    1997-01-01

    The design of satellite constellations requires an understanding of the dynamic global coverage provided by the constellations. Even for a small constellation with a simple circular orbit propagator, the combinatorial nature of the analysis frequently renders the problem intractable. Particularly for the initial design phase where the orbital parameters are still fluid and undetermined, the coverage information is crucial to evaluate the performance of the constellation design. We have developed a fast and simple algorithm for determining the global constellation coverage dynamically using image processing techniques. This approach provides a fast, powerful and simple method for the analysis of global constellation coverage.

  3. 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

    ... when price evaluation for shipments from various shipping points is contemplated: Shipping Point(s... 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...

  4. 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.

  5. 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

  6. 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

  7. 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...

  8. 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...

  9. 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

    ... 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...

  10. 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

    ... 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...

  11. Star Numbers and Constellations.

    ERIC Educational Resources Information Center

    Francis, Richard L.

    1993-01-01

    A number for which the number of digits categorizes the number is called a star number. A set of star numbers having a designated property is called a constellation. Discusses nature and cardinality of constellations made up of star square, star prime, star abundant, and star deficient numbers. Presents five related problems for exploration. (MDH)

  12. GPM Constellation with Clock

    NASA Video Gallery

    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...

  13. On the Origins of Pointing in Infancy: A Pilot Study.

    ERIC Educational Resources Information Center

    Butterworth, George; Adamson-Macedo, Elvidina

    Observations were made of the incidence of pointing behavior among infants differing in age when a radio-controlled truck entered the room in which mother and infant were seated. Infants' reactions over 5 to 6 minutes were recorded on videotape. Recordings were analyzed to establish the incidence of pointing, handedness of pointing, whether…

  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. 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. PMID:23777818

  17. 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.

  18. 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

  19. 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.

  20. 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…

  1. 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.

  2. Origins of nonlocality near the neutrality point in graphene.

    PubMed

    Renard, Julien; Studer, Matthias; Folk, Joshua A

    2014-03-21

    We present an experimental study of nonlocal electrical signals near the Dirac point in graphene. The in-plane magnetic field dependence of the nonlocal signal confirms the role of spin in this effect, as expected from recent predictions of the Zeeman spin Hall effect in graphene, but our experiments show that thermo-magneto-electric effects also contribute to nonlocality, and the effect is sometimes stronger than that due to spin. Thermal effects are seen to be very sensitive to sample details that do not influence other transport parameters. PMID:24702396

  3. The Relationship between Marital Adjustment and Sibling Constellation.

    ERIC Educational Resources Information Center

    Bloser, Edward Charles

    The conflict in research that exists between the relationship of marital adjustment and sibling constellation is examined here. The belief that the combination of birth order and gender (sibling constellation) is important, is not only a part of folk wisdom but it is a continuing point of view in the literature of marital and family therapy. Data…

  4. Commanding Constellations (Pipeline Architecture)

    NASA Technical Reports Server (NTRS)

    Ray, Tim; Condron, Jeff

    2003-01-01

    Providing ground command software for constellations of spacecraft is a challenging problem. Reliable command delivery requires a feedback loop; for a constellation there will likely be an independent feedback loop for each constellation member. Each command must be sent via the proper Ground Station, which may change from one contact to the next (and may be different for different members). Dynamic configuration of the ground command software is usually required (e.g. directives to configure each member's feedback loop and assign the appropriate Ground Station). For testing purposes, there must be a way to insert command data at any level in the protocol stack. The Pipeline architecture described in this paper can support all these capabilities with a sequence of software modules (the pipeline), and a single self-identifying message format (for all types of command data and configuration directives). The Pipeline architecture is quite simple, yet it can solve some complex problems. The resulting solutions are conceptually simple, and therefore, reliable. They are also modular, and therefore, easy to distribute and extend. We first used the Pipeline architecture to design a CCSDS (Consultative Committee for Space Data Systems) Ground Telecommand system (to command one spacecraft at a time with a fixed Ground Station interface). This pipeline was later extended to include gateways to any of several Ground Stations. The resulting pipeline was then extended to handle a small constellation of spacecraft. The use of the Pipeline architecture allowed us to easily handle the increasing complexity. This paper will describe the Pipeline architecture, show how it was used to solve each of the above commanding situations, and how it can easily be extended to handle larger constellations.

  5. Origins of Nonlocality Near the Neutrality Point in Graphene

    NASA Astrophysics Data System (ADS)

    Folk, Joshua

    Nonlocal measurements are an effective experimental tool for probing non-charge characteristics of carriers using a (charge) transport measurement. For example, nonlocal signals in a Hall bar geometry can indicate spin currents, or valley currents, or heat currents flowing through a sample without an accompanying charge current. We present an experimental study of nonlocal electrical signals near the Dirac point in graphene, with the goal of disentangling the various types of current that might give rise to nonlocality. The in-plane magnetic field dependence of the nonlocal signal confirms the role of spin in this effect, as expected from predictions of the Zeeman spin Hall effect in graphene, but our experiments show that thermo-magneto-electric effects also contribute to nonlocality, and the effect is sometimes stronger than that due to spin.

  6. BRITE-Constellation

    NASA Astrophysics Data System (ADS)

    Weiss, W. W.; Moffat, A., Kudelka, O.

    2008-12-01

    BRITE-Constellation, a project developed since 2003 by researchersxE2x88x97 at Canadian and Austrian Universities presently consists of UniBRITE and BRITE-Austria/TUG-SAT1, which are two 20 cm cube nanosatellites. Each will fly a 30 mm aperture telescope with a CCD camera equipped with either a red (550 to 700 nm) or a blue (390 to 460 nm) filter, to perform high-precision two-color photometry of the brightest stars in the sky ( ≤ 4th mag) for up to several years. Stars of up to two magnitudes fainter will be observed simultaneously with reduced accuracy in an on-board photometric mode. Depending on the orbit and the position of the BRITE targets the photometry can be obtained contiguously during many orbits for many months, with gaps during individual orbits, or only for certain periods of the year. The primary science goals are studies of massive and luminous stars in our neighbourhood, representing objects which dominate the ecology of our Universe, and of evolved stars (giants) to probe the future development of our Sun. The wide field cameras (24◦ ) will also obtain data from other scientifically interesting stars to investigate their stellar structure and evolution. All of this is enabled by innovative technology currently developed in collaboration between Canada and Austria. A launch of UniBRITE and BRITE-Austria in 2009 is envisioned and an expansion proposal of the BRITE-Constellation by two dditional spacecrafts of the same construction, to be funded by the Canadian Space Agency (CSA), is currently under review. A comprehensive description of scientific and technical aspects of BRITE-Constellation is being prepared for publication in Communications in Asteroseismology. The BRITE- Constellation web site can be found at www.brite-constellation.at. A first Announcement of Opportunity for submitting BRITE-Constellation observing proposals was issued at http://ams.astro.univie.ac.at/BRITE AO/BRITE AO.html

  7. Brite-Constellation: A status report

    NASA Astrophysics Data System (ADS)

    Kaiser, A.; Kuschnig, R.; Weiss, W. W.; BRITE-Constellation Team

    2012-12-01

    The BRITE-Constellation, short for ``BRIght Target Explorer" Constellation, is a group of six nanosatellites from Austria, Poland and Canada carrying thirty millimeter aperture optical telescopes with a CCD camera. The goal of the mission is to photometrically measure low-level oscillations and temperature variations of the brightest stars in the sky down to a visual magnitude of 4.0, with unprecedented precision and time coverage not achievable from ground in two colors. The improved three-axis pointing performance which is a critical element that makes this high precision photometry mission feasible is a recent development by the University of Toronto's Space Flight Laboratory. The University of Vienna and the FFG/ALR (Austria's space agency) are financing the development of two satellites. The Polish Academy of Sciences is funding two additional satellites as well as the Canadian Space Agency resulting in six components for the constellation.

  8. 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.

  9. 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.

  10. Autonomous interplanetary constellation design

    NASA Astrophysics Data System (ADS)

    Chow, Cornelius Channing, II

    According to NASA's integrated space technology roadmaps, space-based infrastructures are envisioned as necessary ingredients to a sustained effort in continuing space exploration. Whether it be for extra-terrestrial habitats, roving/cargo vehicles, or space tourism, autonomous space networks will provide a vital communications lifeline for both future robotic and human missions alike. Projecting that the Moon will be a bustling hub of activity within a few decades, a near-term opportunity for in-situ infrastructure development is within reach. This dissertation addresses the anticipated need for in-space infrastructure by investigating a general design methodology for autonomous interplanetary constellations; to illustrate the theory, this manuscript presents results from an application to the Earth-Moon neighborhood. The constellation design methodology is formulated as an optimization problem, involving a trajectory design step followed by a spacecraft placement sequence. Modeling the dynamics as a restricted 3-body problem, the investigated design space consists of families of periodic orbits which play host to the constellations, punctuated by arrangements of spacecraft autonomously guided by a navigation strategy called LiAISON (Linked Autonomous Interplanetary Satellite Orbit Navigation). Instead of more traditional exhaustive search methods, a numerical continuation approach is implemented to map the admissible configuration space. In particular, Keller's pseudo-arclength technique is used to follow folding/bifurcating solution manifolds, which are otherwise inaccessible with other parameter continuation schemes. A succinct characterization of the underlying structure of the local, as well as global, extrema is thus achievable with little a priori intuition of the solution space. Furthermore, the proposed design methodology offers benefits in computation speed plus the ability to handle mildly stochastic systems. An application of the constellation design

  11. Chinese Constellations and Star Maps

    NASA Astrophysics Data System (ADS)

    Sun, Xiaochun

    Star observations can be traced back to as early as the twenty-third century BC in ancient China. By the fifth century BC, the Chinese had named the 28 asterisms that formed the basic reference points for the Chinese equatorial coordinate system. By the first century BC, the Chinese had developed a unique system of constellations that reflected Chinese cosmological ideas with the central theme of the correlation between Heaven and Man. Star charts have been discovered on tomb ceilings dating back to Han times. But most of them are illustrative in their presentation of stars. The Dunhuang star maps from the ninth century, the star maps in the Xin yixiang fa yao of the eleventh century, and the Suzhou Astronomical Planisphere of the thirteenth century are examples of precise star maps from ancient China.

  12. 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

  13. 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.

  14. 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.

  15. Constellations and Networks

    NASA Astrophysics Data System (ADS)

    Greenwald, R. A.

    2013-12-01

    Constellations and Networks Prior to the late 1970's, most satellites probing the Earth's upper atmosphere, ionosphere, and magnetosphere and most ground-based experiments measuring the upper atmosphere and ionosphere provided uncoordinated, localized measurements of different regions of the Earth's near-space environment with the objective of determining their basic properties. These measurements showed that the magnetosphere was divided into a number of regions, each containing plasmas with different properties and varying concentrations of energetic particles. By the mid 1970's, this discovery phase of the various regions of the Earth's magnetosphere had essentially been completed. The next step was to understand how the various plasma domains of the magnetosphere and ionosphere were coupled into a complex plasma system and how energy flowed through this system from the solar wind to the upper atmosphere. To achieve this goal, satellite missions sponsored by NASA, ESA, and ISAS became more complex beginning with ISEE and extending to ISTP, Cluster, and many others. Specifically, the research effort evolved into coordinated multipoint measurements provided by constellations of spacecraft, all with on-board propulsion and station-keeping capability. During the same period, other scientific funding agencies in many countries supplemented the satellite-based research effort with the development of ground-based instrumentation networks capable of remote sensing the ionosphere and upper atmosphere. These networks provide measurements that complement the satellite data sets by providing large-scale contextual views of the state of the ionosphere and magnetically conjugate determinations of important physical parameters such as ionospheric electric fields and current systems. In this paper I discuss several of these ground-based networks and highlight research areas where they have made important contributions to satellite constellation missions as well as other topic

  16. Origin of electrical signals for plasma etching end point detection: Comparison of end point signals and electron density

    SciTech Connect

    Sobolewski, Mark A.; Lahr, David L.

    2012-09-15

    Electrical signals are used for end point detection in plasma etching, but the origin of the electrical changes observed at end point is not well understood. As an etch breaks through one layer and exposes an underlayer, the fluxes and densities of etch products and reactants in the gas phase will change. The resulting perturbation in gas composition may alter the plasma electron density, which in turn may affect the electrical signals. Alternatively, changes in substrate electrical properties or surface properties, such as work function or emitted electron yield, may be involved. To investigate these effects, experiments were performed in a radio-frequency (rf)-biased, inductively coupled reactor, during CF{sub 4}/Ar plasma etching of silicon dioxide films on silicon substrates. A complete set of electrical parameters, for the bias as well as the inductive source, was measured and compared. The most useful end point signal was found to be the fundamental rf bias impedance, which decreases when the oxide is removed. A simultaneous increase in plasma electron density was measured by a wave cutoff probe. Analytical sheath models indicate that the measured change in electron density accounts for nearly all of the impedance decrease. The change in electron density can in turn be explained by the effects of etch products or reactants on gas composition. In contrast, electrons emitted from the wafer surface play at most a minor role in the changes in electron density and impedance observed at end point.

  17. 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.

  18. The THEMIS Constellation

    NASA Astrophysics Data System (ADS)

    Harvey, P.; Taylor, E.; Sterling, R.; Cully, M.

    2008-12-01

    The Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission is the fifth NASA Medium-class Explorer (MIDEX), launched on February 17, 2007 to determine the trigger and large-scale evolution of substorms. The mission employs five identical micro-probes (termed “probes”), which have orbit periods of one, two and four days. Each of the Probes carries five instruments to measure electric and magnetic fields as well as ions and electrons. Each probe weighs 134 kg including 49 kg of hydrazine fuel and measures approximately 0.8×0.8×1.0 meters ( L× W× H) and operates on an average power budget of 40 watts. For launch, the Probes were integrated to a Probe Carrier and separated via a launch vehicle provided pyrotechnic signal. Attitude data are obtained from a sun sensor, inertial reference unit and the instrument Fluxgate Magnetometer. Orbit and attitude control use a RCS system having two radial and two axial thrusters for roll and thrust maneuvers. Its two fuel tanks and pressurant system yield 960 meters/sec of delta-V, sufficient to allow Probe replacement strategies. Command and telemetry communications use an S-band 5 watt transponder through a cylindrical omni antenna with a toroidal gain pattern. This paper provides the key requirements of the probe, an overview of the probe design and how they were integrated and tested. It includes considerations and lessons learned from the experience of building NASA’s largest constellation.

  19. Report of the Constellations Panel

    NASA Technical Reports Server (NTRS)

    Bents, D. J.; Vontiesenhausen, G.; Lundquist, C. A.; Swan, P.; Mayer, H. L.; Mangano, M. J.; Bergamasui, S.; Bevilacqua, F.; Williams, F.; Rum, G.

    1985-01-01

    The purpose of a constellation is to provide a mode of distributing space systems in a method that could be advantageous and not eliminating the consolidation/aggregation advantages. The applicability of stabilization concepts to various orbital conditions was defined.

  20. 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

  1. 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.

  2. Measurement and modeling of bentazone in the river Main (Germany) originating from point and non-point sources.

    PubMed

    Bach, M; Letzel, M; Kaul, U; Forstner, S; Metzner, G; Klasmeier, J; Reichenberger, S; Frede, H G

    2010-06-01

    A Water Framework Directive pilot project combines measured data and model approaches to calculate fluxes and mass balance of the pesticide bentazone in an 81 km section of the river Main (Germany). During the study period (six weeks in spring 2004) the observed bentazone inflow and outflow in the river section amounted to 52.8 and 53.1 kg, respectively; the maximum concentrations reached 220 and 290 ng l(-1). Based on sampling of seven sewage treatment plants a specific loss of 0.87 g bentazone per farm was calculated. Extrapolation to the entire sub-basin results in 2.6 kg bentazone in total as point source contribution from farms. Diffuse input into the surface water network occurred after an intensive rainfall event on May 7th. Total bentazone load was simulated with the pesticide emission model DRIPS to be 23.2 kg. One third of this load was estimated to be degraded by photolysis before reaching the main waterway, the river Main. The ATV water quality model was applied to predict the concentration profile of bentazone in river Main between Schweinfurt and Würzburg with reasonable results. The difference between total measured and modeled fluxes amounted to 1.5 kg corresponding to 2% of the overall input. The combined approach of monitoring and modeling appears to be a valuable strategy to quantify the relevance of point and non-point sources and to focus effective mitigation measures to the most relevant origins within a river basin. PMID:20546837

  3. 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.…

  4. 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.

  5. 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.

  6. Single point off-center helium ignitions as origin of some Type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Forcada, Ramon; Garcia-Senz, Domingo; José, Jordi

    The explosion of a helium layer accreted on top of a white dwarf, leading to the subsequent explosion of the star (while the accreting dwarf is still below the Chandrasekhar mass limit) is an alternative model for some subluminous Type Ia supernovae explosions. In this communication we present two preliminary hydrodynamical simulations concerning these so- called Sub-Chandrasekhar mass models for Type Ia supernovae, calculated in two dimensions. In the first calculation we have assumed one single detonation travelling through the helium layer which, after a while, induces the detonation of the carbon layer at the antipodes of the original ignition point. In the second case we assumed the prompt detonation of the carbon just beneath the ignition point. A comparison between these two models is presented.

  7. 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.

  8. 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.

  9. The replication origin decision point is a mitogen-independent, 2-aminopurine-sensitive, G1-phase event that precedes restriction point control.

    PubMed Central

    Wu, J R; Gilbert, D M

    1997-01-01

    At a distinct point during G1 phase (the origin decision point [ODP]), Chinese hamster ovary (CHO) cell nuclei experience a transition (origin choice) that is required for specific recognition of the dihydrofolate reductase (DHFR) origin locus by Xenopus egg extracts. We have investigated the relationship between the ODP and progression of CHO cells through G1 phase. Selection of the DHFR origin at the ODP was rapidly inhibited by treatment of early G1-phase cells with the protein kinase inhibitor 2-aminopurine (2-AP). Inhibition of the ODP required administration of 2-AP at least 3 h prior to phosphorylation of the retinoblastoma tumor suppressor protein (Rb) and the restriction point (R point). Cells deprived of either serum or isoleucine from metaphase throughout early G1 phase acquired the capacity to replicate in Xenopus egg extract (replication licensing) and subsequently passed through the ODP on the same schedule as cells cultured in complete growth medium. After growth arrest at the R point with hypophosphorylated Rb protein, serum- or isoleucine-deprived cells experienced a gradual loss of replication licensing. However, recognition of the DHFR origin by Xenopus egg cytosol remained stable in growth-arrested cells until the point at which all nuclei had lost the capacity to initiate replication. These results provide evidence that the ODP requires a mitogen-independent protein kinase that is activated after replication licensing and prior to R-point control. PMID:9234688

  10. 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

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

    PubMed

    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 frame conflict

  12. 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.

  13. Optimized orbits for the constellation of Space Station polar platforms

    NASA Technical Reports Server (NTRS)

    Chase, Robert; Mundt, Michael

    1989-01-01

    The orbital configuration of the Eos polar-platform constellation is examined to determine if baseline orbital parameters are appropriately specified to meet the mission task of measuring global oceanic mesoscale variability. Using the Nyquist sampling theorem, spatial and temporal measurement requirements are first established for the constellation. Based upon these requirements, the optimum solution indicates that a total of five spacecraft equipped with nadir-pointing altimeters, or two multibeam-equipped platforms, would be required to meet the mesoscale mapping task. Additional analyses were performed on both one- and and two-platform configurations as well as the complete four-platform Eos constellation. The results of these calculations show that the preferred scenario would be to equip all four Eos polar platforms with multibeam altimeters.

  14. 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.

  15. 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.

  16. 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.

  17. [Variations in the position and point of origin of the vermiform appendix].

    PubMed

    Delić, Jasmin; Savković, Admedina; Isaković, Eldar

    2002-01-01

    There were investigated variations of appendix vermiformis in the place of origin and position. The investigations were carried out on 50 human preparations of adults of both sexes, unintentional choice. The position and relation between intestinum caecum and appendix vermiformis were determined by forensic medical and pathoanatomical autopsy. Place of origin of appendix vermiformis, from wall of intestinum caecum is determined by anatomical dissection. Intestinum caecum has a variable shape and it occurs in two forms: conical, which dominates (56%) and square (44%). It has constant position in fossa iliaca dextra in 100% of 50 investigated cases. Appendix vermiformis is fully variable organ as for position and the place of origin from the wall of intestinum caecum. Dominantly (52%) it has rising position, and two subtypes are present: retrocecal (more expressed-38%) related to the retrocolic subtype (14%). Very frequent position of appendix vermiformis is a falling one (32%), in which pelvic position is more frequent (26%) related to descendent position (6%). Appendix vermifirmis is located subcaecaly in 8% of total number of investigated cases, found in three subtypes. It is found out that ostium appendicis vermiformis has a variable position in the wall of intestinum caecum. It is predominantly placed in the middle of the lower pole of the intestinum caecum (58%), in medial wall it is present in 32%, of all investigated, and in the lateral wall in the least number case 10%. The results of these investigations point out how important is to know variable anatomies of appendix vermiformis, for the clinical image of acute appendicitis is undoubtedly caused by the variable anatomical relations. PMID:11917693

  18. Relative motion and visibility evaluation in GNSS constellation: A projection method

    NASA Astrophysics Data System (ADS)

    Lin, Jinmao; Wang, Yueke; Zhou, Yongbin; Yang, Jun

    2016-04-01

    Using crosslinks to network the satellites in a GNSS constellation has been regarded as one of the most important trends for the GNSS modernisation. The motion and visibility of the satellites w.r.t. each other in the constellation have to be evaluated as an prerequisite to many tasks, especially to the inter-satellite network design, measurement scheduling and pointing-related issues. Thus far, very few analytical studies have been done on this issue for GNSS constellations. In this paper, a projection method is proposed to evaluate the relative motion and visibility. By projecting the relative trajectory orthogonally onto the orbital plane of the base satellite, it is much easier to study the geometric characteristics of the relative motion and the effect of constellation parameters and field-of-view constraint on the relative visibility. Given that GNSS constellations are designed based on Walker constellation, the relative motion pattern is explored algorithmically with index mapping techniques and the always visible relationship is visually modelled using a graph which in most cases shows a symmetry structure when the vertices are placed in a proper order. As demonstration of our method, a thorough experimental validation on the nominal GPS, GLONASS, Galileo and BeiDou-M constellation is proposed. The result explicitly reveals that the relative motion and visibility varies according to the parameters of the constellations.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 41 CFR 302-9.142 - What will I be reimbursed if I transport a POV from a point of origin that is different from the...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... reimbursed if I transport a POV from a point of origin that is different from the authorized point of origin... STORAGE OF A PRIVATELY OWNED VEHICLE Transportation Pov Transportation at Time of Assignment § 302-9.142 What will I be reimbursed if I transport a POV from a point of origin that is different from...

  4. 41 CFR 302-9.142 - What will I be reimbursed if I transport a POV from a point of origin that is different from the...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... reimbursed if I transport a POV from a point of origin that is different from the authorized point of origin... STORAGE OF A PRIVATELY OWNED VEHICLE Transportation Pov Transportation at Time of Assignment § 302-9.142 What will I be reimbursed if I transport a POV from a point of origin that is different from...

  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, 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..., PAPERS, AND EQUIPMENT (PBP&E) General Rules § 302-7.6 What are the authorized origin and destination points for the transportation of HHG and PBP&E? The authorized origin and destination points for...

  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. 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.

  10. 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

  11. 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

    ... hearing was published in the Federal Register on July 7, 2011 (76 FR 39910). No comments or hearing... 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...

  12. 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

  13. The CEOS constellation for land surface imaging

    NASA Astrophysics Data System (ADS)

    Bailey, G. Bryan; Berger, Michael; Jeanjean, Hervé; Gallo, Kevin P.

    2007-10-01

    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 submeter 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.

  14. 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.

  15. Constellation choosing based on multi-dimensional sphere packing technique

    NASA Astrophysics Data System (ADS)

    Jinghe, Li; Guijun, Hu; Kashero, Enock; Zhaoxi, Li

    2016-09-01

    In this paper we address the sphere packing lattice points selection problem being used as constellation points in high-dimensional modulation. We propose a new type of points selection method based on threshold theory. Theoretically, this method improves the transmission performance of high-dimensional signal modulation systems. We find that the BER of a 4D modulation signal using the threshold value points selection method reduces. We also compared random and distant points selection methods in a BER of 10-3 and obtained a reduced SNR of about 2 db. At a 10-3 BER, a 8D modulation signal with points selected using the threshold selection methods obtained a reduced SNR of about 3 db. At a 10-3 BER, a 16D modulation signal with points selected using the threshold selection methods obtained a reduced SNR of about 3.5 db.

  16. 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.

  17. 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.

  18. 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.

  19. Origins.

    ERIC Educational Resources Information Center

    Online-Offline, 1999

    1999-01-01

    Provides an annotated list of resources dealing with the theme of origins of life, the universe, and traditions. Includes Web sites, videos, books, audio materials, and magazines with appropriate grade levels and/or subject disciplines indicated; professional resources; and learning activities. (LRW)

  20. 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.

  1. 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.

  2. Cross Calibration of the Afternoon Constellation's

    NASA Video Gallery

    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...

  3. Monitoring coastal marine waters for spore-forming bacteria of faecal and soil origin to determine point from non-point source pollution.

    PubMed

    Fujioka, R S

    2001-01-01

    The US Environmental Protection Agency (USEPA) and the World Health Organization (WHO) have established recreational water quality standards limiting the concentrations of faecal indicator bacteria (faecal coliform, E. coli, enterococci) to ensure that these waters are safe for swimming. In the application of these hygienic water quality standards, it is assumed that there are no significant environmental sources of these faecal indicator bacteria which are unrelated to direct faecal contamination. However, we previously reported that these faecal indicator bacteria are able to grow in the soil environment of humid tropical island environments such as Hawaii and Guam and are transported at high concentrations into streams and storm drains by rain. Thus, streams and storm drains in Hawaii contain consistently high concentrations of faecal indicator bacteria which routinely exceed the EPA and WHO recreational water quality standards. Since, streams and storm drains eventually flow out to coastal marine waters, we hypothesize that all the coastal beaches which receive run-off from streams and storm drains will contain elevated concentrations of faecal indicator bacteria. To test this hypothesis, we monitored the coastal waters at four beaches known to receive water from stream or storm drains for salinity, turbidity, and used the two faecal indicator bacteria (E. coli, enterococci) to establish recreational water quality standards. To determine if these coastal waters are contaminated with non-point source pollution (streams) or with point source pollution (sewage effluent), these same water samples were also assayed for spore-forming bacteria of faecal origin (Cl. perfringens) and of soil origin (Bacillus species). Using this monitoring strategy it was possible to determine when coastal marine waters were contaminated with non-point source pollution and when coastal waters were contaminated with point source pollution. The results of this study are most likely

  4. 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.,...

  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, 2010 CFR

    2010-07-01

    ... is no port or terminal at the point of origin and/or destination? 302-9.104 Section 302-9.104 Public... Transportation General § 302-9.104 What may I do if there is no port or terminal at the point of origin and/or destination? If there is no port or terminal at the point of origin and/or destination, your agency will...

  6. Analysis of a Constellation Lab Cooperative Learning Activity

    NASA Astrophysics Data System (ADS)

    Gauthier, A. J.

    2001-12-01

    A cooperative learning activity was designed for use in the undergraduate laboratory course Introduction to Astronomical Observation. This group exercise enhances the student's learning of constellations and will hopefully increase retention of the material throughout the semester. It also serves as an "ice-breaker" during the first week of lab, promoting student involvement and vested interest in the course. To gain some insight into the student mind, a survey was conducted to evaluate the usefulness and overall opinion of this method. The students who completed the survey had previously been enrolled in a pre-requisite astronomy course that also required a constellation lab. In this previous course they "learned" the constellations from an instructor and a flashlight beam, studied them on their own, and then promptly took a quiz. Both methods are analyzed from an instructional designer's point of view and suggestions for future activities are presented. The preliminary results and accompanying activity will be discussed in poster and hand-out medium.

  7. 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. PMID:26203042

  8. 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.

  9. 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.

  10. Haplotypes in the Dystrophin DNA Segment Point to a Mosaic Origin of Modern Human Diversity

    PubMed Central

    Ziętkiewicz, Ewa; Yotova, Vania; Gehl, Dominik; Wambach, Tina; Arrieta, Isabel; Batzer, Mark; Cole, David E. C.; Hechtman, Peter; Kaplan, Feige; Modiano, David; Moisan, Jean-Paul; Michalski, Roman; Labuda, Damian

    2003-01-01

    Although Africa has played a central role in human evolutionary history, certain studies have suggested that not all contemporary human genetic diversity is of recent African origin. We investigated 35 simple polymorphic sites and one Tn microsatellite in an 8-kb segment of the dystrophin gene. We found 86 haplotypes in 1,343 chromosomes from around the world. Although a classical out-of-Africa topology was observed in trees based on the variant frequencies, the tree of haplotype sequences reveals three lineages accounting for present-day diversity. The proportion of new recombinants and the diversity of the Tn microsatellite were used to estimate the age of haplotype lineages and the time of colonization events. The lineage that underwent the great expansion originated in Africa prior to the Upper Paleolithic (27,000–56,000 years ago). A second group, of structurally distinct haplotypes that occupy a central position on the tree, has never left Africa. The third lineage is represented by the haplotype that lies closest to the root, is virtually absent in Africa, and appears older than the recent out-of-Africa expansion. We propose that this lineage could have left Africa before the expansion (as early as 160,000 years ago) and admixed, outside of Africa, with the expanding lineage. Contemporary human diversity, although dominated by the recently expanded African lineage, thus represents a mosaic of different contributions. PMID:14513410

  11. 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.

  12. 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

  13. On the origin of deletions and point mutations in Duchenne muscular dystrophy: most deletions arise in oogenesis and most point mutations result from events in spermatogenesis.

    PubMed Central

    Grimm, T; Meng, G; Liechti-Gallati, S; Bettecken, T; Müller, C R; Müller, B

    1994-01-01

    We present the results of a study of the rate and origin of mutations in Duchenne muscular dystrophy (DMD). Depending on the type of mutation (deletion/duplication or point mutation) present in the patient, there are widely varying ratios of male to female mutation rates. In deletions, the male mutation rate is only 30% of the female one. In non-deletional/non-duplicational mutations (presumably containing a high proportion of point mutations) the male mutation rate is at least 2.2 as high as the female one and probably much higher. Allowing for the presence of autosomal recessive phenocopies we find that k in non-deletional/non-duplicational mutations is 40.3. These findings mean that the vast majority of deletions arise in oogenesis, while most point mutations stem from spermatogenesis. Previous investigations have shown that in other diseases and genes, most notably haemophilia B and A, but also the ZFY and ZFX genes, the male mutation rate for point mutations tends to be higher than the female one. Our results can be seen as a confirmation of this for the special case of DMD. The influence on risk figures is considerable. As an example, the risk of the mother of an isolated case of DMD without an apparent structural anomaly of the gene of being a carrier increases from 67% to at least 76%. Given the estimate of 40.3 for k, allowing for the presence of autosomal recessive phenocopies mentioned above, it increases even further to 98%. However, as confidence intervals are still large, more data are needed to improve the estimates. Germinal mosaicism in this context is discussed. PMID:8014964

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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, 2011 CFR

    2011-07-01

    ... FOR TRANSPORTATION AND EMERGENCY STORAGE OF A PRIVATELY OWNED VEHICLE Return Transportation of a POV From a Post of Duty § 302-9.207 What will I be reimbursed if I transport my POV from a point of origin... reimbursed if I transport my POV from a point of origin or to a destination that is different from...

  19. 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, 2010 CFR

    2010-07-01

    ... FOR TRANSPORTATION AND EMERGENCY STORAGE OF A PRIVATELY OWNED VEHICLE Return Transportation of a POV From a Post of Duty § 302-9.207 What will I be reimbursed if I transport my POV from a point of origin... reimbursed if I transport my POV from a point of origin or to a destination that is different from...

  20. 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‰.

  1. 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

  2. Status of Constellation Pressure Garment Development

    NASA Technical Reports Server (NTRS)

    Ross, Amy; Aitchison, Lindsay; Daniel, Brian

    2009-01-01

    The Constellation Program requires the development of a space suit system to meet new requirements for launch, entry, and abort crew survival functions, microgravity intravehicular and extravehicular activities, and lunar surface exploration. This paper summarizes recent work and the current status of the NASA Constellation Space Suit Element Pressure Garment and Crew Survival Subsystem (PG/CS). The emphasis of the work by the PGS/CS team has been in the areas of feasibility studies toward PGS/CS architecture definition, risk mitigation, and requirements development. Included are results from component level engineering studies, testing in the Orion Vehicle and Orion seat mockups, microgravity testing on the Reduced Gravity Aircraft, occupant protection sled testing, analyses and studies, and their implications on Constellation PG/CS subsystem.

  3. 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.

  4. 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.

  5. Evolvable Lunar Navigation and Communication Constellations

    NASA Astrophysics Data System (ADS)

    Hamera, Kathryn E.; Mosher, T.

    2008-05-01

    Several international space agencies have announced plans for future lunar exploration missions, including orbiters, rovers, and the eventual build-up of a lunar outpost. Each of these missions will have certain communication and navigation requirements. Some missions will explore parts of the lunar environment that are not directly visible to the Earth, and a lunar relay element will be necessary to provide critical communication and navigation support. Previous research has shown the advantages of using halo orbits for a lunar relay. Halo orbit insertion costs are less than those for geostationary orbit, station-keeping costs are minimal, and the Earth is visible for 100% of the spacecraft's orbital period. An example constellation was designed to show the feasibility of a halo orbit constellation. The methodologies used to construct the example constellation can be tailored to design halo orbit constellations to meet the coverage needs of any lunar mission. Additionally, the halo orbits are selected such that low energy-transfers may be used to transfer spacecraft between halo orbits for very small maneuver costs. This follow-on research demonstrates the capability of the constellation to evolve and reconfigure through the use of low-energy transfers. Using low-energy transfers, multiple space agencies can utilize the same lunar relay constellation by reconfiguring the spacecraft to provide optimal coverage for different missions at different times. This research was funded by a grant from NASA's Exploration System Mission Directorate to the Colorado Space Grant Consortium and a Graduate Student Research Fellowship from the National Science Foundation.

  6. 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.

  7. 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.

  8. 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.

  9. Combined constellations GPS and Galileo systems

    NASA Astrophysics Data System (ADS)

    Januszewski, Jacek

    As for the users of satellite navigation systems the actual slogan is GPS and Galileo the advantages and disadvantages of different combined constellations of these systems must be taken into account. The distributions (in per cent) of the numbers of satellites visible by the observer at different latitudes situated in open and restricted (urban canyon) area for different masking elevation angles (Hmin) for two combined constellations GPS + Galileo systems (I - 29 GPS satellites + 27 Galileo satellites, II - 29 GPS + 30 Galileo) are presented in this paper. In addition to it the detailed distributions for the observer at latitudes 50-60° for other constellations & elevation angles are demonstrated. For the first constellation the difference between the number of GPS satellites visible by the observer above horizon (Hmin = 0°) at latitudes 50-60° and the number of Galileo satellites visible by the same observer at the same time can be equal each number between plus 7 and minus 7. This fact must be taken into account in the production and the determination of the number of channel of GPS-Galileo integrated receivers.

  10. 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.

  11. 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.

  12. Some notes on the Inka constellations

    NASA Astrophysics Data System (ADS)

    Pacheco, Elluz; Flores, Soraya; Salazar, Erwin

    2011-06-01

    The research carried out so far on the identification of constellations in the Inka civilisation is far from exhaustive, as there is both a great difficulty in obtaining the data and much heterogeneity in the information gathered. A brief presentation is given here.

  13. 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…

  14. Relationships between Social Cognition and Sibling Constellations.

    ERIC Educational Resources Information Center

    Goebel, Barbara L.

    1985-01-01

    First and second born college students (N=178) responded to measures of four social cognition factors. Multivariate analysis of variance identified relationships of social cognition factors with five sibling constellation components: subject's sex, subject's birth order (first or second), adjacent first or second born sibling's sex, spacing…

  15. Capabilities of lightsat constellation for operational altimetry

    NASA Astrophysics Data System (ADS)

    Aguttes, J. P.; Bellaiche, G.

    1992-08-01

    An overview is given of mission tradeoffs involved in lightsat constellations for operational altimetry. Typical mission requirements for a light satellite system and system constraints are discussed. A typical operational performance of a light satellite system is briefly described, and the lightsat as a tool for international cooperation is addressed.

  16. 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.

  17. 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.

  18. ML-oriented NDA carrier synchronization for general rotationally symmetric signal constellations

    NASA Astrophysics Data System (ADS)

    Moeneclaey, Marc; Dejonghe, Geert

    1994-08-01

    In this contribution we point out that the nondecision-aided (NDA) carrier synchronizer, maximizing the low E(sub s)/N(sub o) limit of the likelihood function averaged over a general 2(pi) /N-rotationally symmetric signal constellation, reduces to the familiar timing-aided Nth power synchronizer. Whereas in the case of M-PSK the tracking error variance of this NDA ML synchronizer is known to converge to the Cramer-Rao bound (CRB) with increasing E(sub s)/N(sub o), we show that for other rotationally symmetric constellations (such as QAM) the tracking error variance is substantially larger than the CRB.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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).

  5. 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.

  6. NASA's Constellation Program: Milestones Towards the Frontier

    NASA Technical Reports Server (NTRS)

    Hanley, Jeffrey M.; Thomas, Lawrence D.; Rhatigan, Jennifer L.; Boatright, Tony J.

    2009-01-01

    This slide presentation reviews the status and progress made in the Constellation Program's work towards the goal of lunar and Martian exploration flights. It includes views of the various components of the program, and reviews the status of the engine tests, and the development of the Ares I-X towards test launch, the Orion Crew Module, the launch abort system, and the ground operations facilities.

  7. 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.

  8. 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.

  9. The Constellation-X Science Case

    NASA Astrophysics Data System (ADS)

    Hornschemeier, Ann E.; White, N.; Tananbaum, H.; Garcia, M.; Petre, R.; Bookbinder, J.

    2006-09-01

    Constellation-X presents a great leap forward in collecting area over current X-ray observatories and will enable high signal-to-noise studies of X-ray sources that are currently too faint for Chandra and XMM-Newton. Thus Constellation-X remains a high-priority mission in reviews by the National Academies and is the next major X-ray observatory under development by NASA. Con-X will carry out high spectral resolution studies of AGN, which currently require heroic megasecond-class observations with Chandra and XMM, in observations as short as 50 ks. Con-X will be able to track material in accretion disks around supermassive black holes on a light-crossing timescale and will study AGN out to at least redshift 6. The imaging (non-dispersive) spectroscopy capability of the mission will be critical to studying extended sources such as clusters of galaxies and supernova remnants. Con-X studies of clusters of galaxies will allow a crucial means of studying dark matter properties and also of studying dark energy. This talk will cover recent updates to the Constellation-X science case considering the new, proposed Con-X Lite approach. We will also discuss the process whereby the high energy astrophysics community may continue to influence the science case for the mission.

  10. 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, 2011 CFR

    2011-07-01

    ... FOR TRANSPORTATION AND EMERGENCY STORAGE OF A PRIVATELY OWNED VEHICLE Return Transportation of a POV From a Post of Duty § 302-9.206 What should I do if there is no port or terminal at my authorized point... there is no port or terminal at my authorized point of origin or authorized destination when I...

  11. 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, 2010 CFR

    2010-07-01

    ... FOR TRANSPORTATION AND EMERGENCY STORAGE OF A PRIVATELY OWNED VEHICLE Return Transportation of a POV From a Post of Duty § 302-9.206 What should I do if there is no port or terminal at my authorized point... there is no port or terminal at my authorized point of origin or authorized destination when I...

  12. 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.

  13. 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

  14. 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(+) . PMID:27028895

  15. 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

  16. 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.

  17. 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

  18. 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.

  19. 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].

  20. Angular Resolution of Multi-Lisa Constellations

    NASA Astrophysics Data System (ADS)

    Wang, Yan; Gong, Xue-Fei

    2010-04-01

    In this article, we present a detailed derivation of the angular resolution of arbitrary sets of LISA (Laser Interferometer Space Antenna) constellations with a toy model for gravitational wave signals, and further generalized to more complicated cases with slowly varying gravitational wave signals of well-defined frequency at any time instant. For future space-borne LISA-like gravitational wave detectors, our results may serve as a conservative quick estimate of the detector's angular resolution and hopefully moreover a reference for the configuration designs.

  1. 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.

  2. Constellation Architecture and System Margins Strategy

    NASA Technical Reports Server (NTRS)

    Muirhead, Brian

    2008-01-01

    NASA's Constellation Program (CxP) is responsible for the definition, design, development, and operations of the flight, ground, and mission operations elements being developed by the United States for the human exploration of the Moon, Mars, and beyond. This paper provides an overview of the latest CxP technical architecture baseline, driving requirements, and reference missions for initial capability to fly to the International Space Station (ISS) and to the Moon. The results of the most recent design decisions and analyses supporting the architecture, including the Ares I, Ares V, Orion crew exploration vehicle, and the Altair lunar lander will be presented.

  3. 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.

  4. The strengths of constellation missions when exploring our atmosphere

    NASA Astrophysics Data System (ADS)

    Ridley, A. J.; Ruf, C. S.; Posselt, D. J.; Rose, R.; Provost, D.

    2014-12-01

    A few constellation mission have been flow by NASA, ESA, DoD and different companies. While some of these missions are with large satellites, such as ESA's Cluster mission, others are with smaller satellites, such as NASA's Themis mission. CubeSats and MicroSats are obviously smaller than monolithic satellites, and are therefore much more constrained in mass, power, volume and data throughput. They are also cheaper and can be launched in constellations or as secondary payloads. Constellations can provide measurements over larger areas and better sampling in time than single satellites in low Earth orbit, which is one of their main advantages. In this presentation, we focus on the CYGNSS constellation mission, which will measure the winds over the ocean. We show how the the mission will be deployed, the constellation measurement strategy, coverage statistics, and repeat times. We will also discuss other constellation missions that have flown or are being planned.

  5. Role of fluid mixing and fault-related sulfide in the origin of the Ray Point Uranium District, south Texas

    SciTech Connect

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

    1983-09-01

    The Lamprecht and Felder deposits are two of many roll-type uranium deposits hosted by the Miocene Oakville Sandstone in the Ray Point (south Texas) uranium district. The deposits in this district are aligned parallel to or are intersected by the Oakville fault which suggests control by the faults on their origin and/or preservation. The Lamprecht and Felder deposits show fundamentally similar patterns of geochemical zonation and of distribution of authigenic iron disulfide (FeS/sub 2/) minerals. Distribution of U, Mo, and Se are typical of roll-type deposits that result from invasion of geochemically reduced rock by oxygenated uranium-bearing solutions. Sulfur content of these deposits is high (as much as 9%), with almost all sulfur occurring as FeS/sub 2/ minerals. Organic carbon is virtually absent. Four distinct stages of FeS/sub 2/ mineral formation are recognized: (1) a generation of isotopically light (delta/sup 34/S < -20%o) preor pyrite, (2) a generation of isotopically light (delta/sup 34/S < -20%o) marcasite that formed mostly before, but also during, ore deposition, (3) a postore generation of isotopically heavy pyrite (delta/sup 34/S > 0%o), and (4) a yet later generation of marcasite with isotopically light sulfur close to the values of stages 1 and 2. The altered tongue in these deposits is anomalous in that it contains FeS/sub 2/ minerals in contrast to other Texas and Wyoming roll-type deposits which typically have an oxidized (ferric iron-bearing) altered tongue. The dominant FeS/sub 2/ mineral in the altered tongue is isotopically heavy pyrite (stage 3) with subordinate amounts of late marcasite (stage 4).

  6. 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.

  7. Receiver autonomous integrity monitoring using a 24-satellite GPS constellation

    NASA Astrophysics Data System (ADS)

    Brown, Alison K.

    A 24-satellite GPS configuration is studied in order to explore the conditions under which both failure detection and isolation are possible using receiver autonomous integrity monitoring (RAIM). Simulation results show that the satellite coverage provided by both the 3-plane and the 6-plane constellations considered are suitable to provide integrity for all phases of flight except for nonprecision approaches. Although the 6-plane constellation has marginally poorer geometry for satellite failure detection than the 3-plane constellation, the average satellite isolation geometry is significantly better, making the 6-plane constellation preferable for RAIM.

  8. 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.

  9. 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.

  10. 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.

  11. Constellation Pathfinder: A University Nanosatellite Project

    NASA Astrophysics Data System (ADS)

    Spence, Harlan E.; Petschek, Harry E.

    2002-08-01

    Under the task of nanosatellite mission design, we developed a mission concept that enables hundreds of one-kilogram spacecraft to be placed into orbit with a single mothership. We performed trade studies to arrive at a positive feasibility assessment. The results of that study were described in two publications. Second, under the task of spacecraft design, we developed nanosatellite designs needed to enable constellation missions. Design studies were conducted and subsystems prototyped, including a spin-table and launcher concept for a small stack of nanosatellites. Engineering design studies of this work appeared in the refereed literature. Instruments to be flown on such a small craft have been specified and then developed as part of a related AF SBIR effort. Undergraduate students (>100 in the Aerospace Engineering, Mechanical Engineering, and Electrical and Computer Engineering departments) played an enormous role in the mission and spacecraft definitions of the Constellation Pathfinder project. In addition to five publications, numerous invited and contributed presentations of these studies have been presented at national and international meetings.

  12. 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

  13. FAST TRACK COMMUNICATION: Affine constellations without mutually unbiased counterparts

    NASA Astrophysics Data System (ADS)

    Weigert, Stefan; Durt, Thomas

    2010-10-01

    It has been conjectured that a complete set of mutually unbiased bases in a space of dimension d exists if and only if there is an affine plane of order d. We introduce affine constellations and compare their existence properties with those of mutually unbiased constellations. The observed discrepancies make a deeper relation between the two existence problems unlikely.

  14. Distributed Avionics and Software Verification for the Constellation Program

    NASA Technical Reports Server (NTRS)

    Hood, Laura E.; Adams, James E.

    2008-01-01

    This viewgraph presentation reviews the planned verification of the avionics and software being developed for the Constellation program.The Constellation Distributed System Integration Laboratory (DSIL) will consist of multiple System Integration Labs (SILs), Simulators, Emulators, Testbeds, and Control Centers interacting with each other over a broadband network to provide virtual test systems for multiple test scenarios.

  15. 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.)

  16. 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.

  17. 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.

  18. 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.

  19. Constellation-X mirror technology development

    NASA Astrophysics Data System (ADS)

    Zhang, W. W.; Bolognese, J.; Byron, G.; Chang, K. W.; Content, D. A.; Hadjimichael, T. J.; He, Charles; Hill, M. D.; Hong, M.; Lehan, J. P.; Lozipone, L.; Mazzarella, J. M.; McClelland, R.; Nguyen, D. T.; Olsen, L.; Petre, R.; Robinson, D.; Rohrbach, S. O.; Russell, R.; Saha, T. T.; Sharpe, M.; Gubarev, M. V.; Jones, W. D.; O'Dell, S. L.; Davis, W.; Caldwell, D. R.; Freeman, M.; Podgorski, W.; Reid, P. B.

    2008-07-01

    As NASA's next major space X-ray observatory, the Constellation-X mission (Bookbinder et al. 2008) requires mirror assemblies with unprecedented characteristics that cannot be provided by existing optical technologies. In the past several years, the project has supported a vigorous mirror technology development program. This program includes the fabrication of lightweight mirror segments by slumping commercially available thin glass sheets, the support and mounting of these thin mirror segments for accurate metrology, the mounting and attachment of these mirror segments for the purpose of X-ray tests, and development of methods for aligning and integrating these mirror segments into mirror assemblies. This paper describes our efforts and developments in these areas.

  20. 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.

  1. 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.

  2. 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).

  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. 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. PMID:26691641

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Dark matter or point sources? Utilizing the 1-pt PDF to understand the origin of the GeV excess seen by the Fermi LAT detector

    NASA Astrophysics Data System (ADS)

    Harrison, Natalie; Gaskins, Jennifer; Fermi LAT Collaboration

    2015-04-01

    An excess of gamma rays from the Inner Galaxy in the Fermi LAT data has been identified. This emission has been interpreted as a possible signature of the annihilation of dark matter particles, or as originating from a collection of unresolved point sources, such as gamma-ray millisecond pulsars. We explore the clustering properties of the diffuse emission arising from a population of gamma-ray point sources and from the annihilation of dark matter particles in the halo of the Galaxy using the 1-pt probability distribution function of counts in pixels (1pt-PDF, the number of pixels with a specified number of counts as a function of counts); this approach is also known as fluctuation analysis or P(D) analysis. We analyze the 1-pt PDF of the GeV excess within a +/- 5 degree box around the Galactic Center. For both dark matter and point sources we adopt the spatial distribution and spectrum to fit the GeV excess. We determine the contributions to the 1-pt PDF from the Galactic diffuse and isotropic diffuse emissions, dark matter, and point sources, and discuss the implications of this analysis for the origin of the GeV excess.

  12. Dark matter or point sources? Utilizing the 1-pt PDF to understand the origin of the GeV excess seen by the Fermi LAT detector

    NASA Astrophysics Data System (ADS)

    Harrison, Natalie; Siegal-Gaskins, Jennifer M.

    2015-01-01

    An excess of gamma rays from the Inner Galaxy in the Fermi LAT data has been identified. This emission has been interpreted as a possible signature of the annihilation of dark matter particles, or as originating from a collection of unresolved point sources, such as gamma-ray millisecond pulsars. We explore the clustering properties of the diffuse emission arising from a population of gamma-ray point sources and from the annihilation of dark matter particles in the halo of the Galaxy using the 1-pt probability distribution function of counts in pixels (1pt-PDF, the number of pixels with a specified number of counts as a function of counts); this approach is also known as fluctuation analysis or P(D) analysis. We analyze the 1-pt PDF of the GeV excess within a +/- 5 degree box around the Galactic Center. For both dark matter and point sources we adopt the spatial distribution and spectrum to fit the GeV excess. We determine the contributions to the 1-pt PDF from the Galactic diffuse and isotropic diffuse emission, dark matter, and point sources, and discuss the implications of this analysis for the origin of the GeV excess.

  13. 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

  14. Development of a prototype nickel optic for the Constellation-X hard x-ray telescope

    NASA Astrophysics Data System (ADS)

    Romaine, S.; Basso, S.; Bruni, R. J.; Burkert, W.; Citterio, O.; Cotroneo, V.; Engelhaupt, D.; Freyberg, M. J.; Gorenstein, P.; Gubarev, M.; Hartner, G.; Mazzoleni, F.; O'Dell, S.; Pareschi, G.; Ramsey, B. D.; Speegle, C.; Spiga, D.

    2007-09-01

    The Constellation-X mission concept has been streamlined to a single Atlas V 551 configuration. This decision was reached by the project team after considering the increases in launch costs announced in 2006 coupled with the constrained budget environment apparent with the release of the NASA 2007 budget. Along with the Spectroscopy X-ray Telescopes, this new configuration continues to carry a Hard X-ray Telescope (HXT) component, with some modifications to the original requirements to adjust to the new configuration. The total effective area requirement in the 7 - 40 keV band has been reduced, but at the same time the angular resolution requirement has been increased from 1 arcmin to 30 arcsec. The Smithsonian Astrophysical Observatory, Marshall Space Flight Center and Brera Observatory, Italy) have been collaborating to develop and HXT which meets the requirements of Constellation-X. The development work we have been engaged in to produce multilayer coated Electroformed-Nickel-Replicate (ENR) shells is well suited for this new configuration. We report here on results of fabrication and testing of a prototyped optic for the HXT. Full beam illumination X-ray tests, taken at MPE-Panter Test Facility, show that these optics meet the new requirement of 30 arcsec for the streamlined Constellation-X configuration. This report also presents preliminary results from studies using titanium nitride as a release agent to simplify and improve the nickel electroforming replication process.

  15. 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.

  16. 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.

  17. 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.

  18. 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...

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

    PubMed

    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

  20. 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).

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Enhancing comprehensive inversions using the Swarm constellation

    NASA Astrophysics Data System (ADS)

    Sabaka, T. J.; Olsen, N.

    2006-04-01

    This paper reports on the findings of a simulation study designed to test various satellite configurations sug-gested for the upcoming Swarm magnetic mapping mission. The test is to see whether the mission objectives of recovering small-scale core secular variation (SV) and lithospheric magnetic signals, as well as information about mantle conductivity structure, can be met. The recovery method used in this paper is known as com-prehensive inversion (CI) and involves the parameterization of all major fields followed by a co-estimation of these parameters in a least-squares sense in order to achieve proper signal separation. The advantage of co-estimation over serial estimation of parameters is demonstrated by example. Synthetic data were calculated for a pool of six Swarm satellites from a model based heavily on the CM4 comprehensive model, but which has more small-scale lithospheric structure, a more complicated magnetospheric field, and an induced field reflecting a 3-D conductivity model. These data also included realistic magnetic noise from spacecraft and payload. Though the parameterization for the CI is based upon that of CM4, modifications have been made to accommodate these new magnetospheric and induced fields, in particular with orthogonality constraints defined so as to avoid covariance between slowly varying induced fields and SV. The use of these constraints is made feasible through an efficient numerical implementation. Constellations of 4, 3, 2, and 1 satellites were considered; that with 3 was able to meet the mission objectives, consistently resolving the SV to about spherical harmonic (SH) degree n = 15 and the lithosphere to a limited n < 90 due to external field leakage, while those with 2 and 1 were not; 4 was an improvement over 3, but was much less than the improvement from 2 to 3. The resolution of the magnetospheric and induced SH time-series from the 3 satellite configuration was sufficient enough to allow the detection of 3-D mantle

  7. 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.; Barton, P. J.; Beene, James R; Bertrand Jr, Fred E; Boswell, M.; Brudanin, V.; Busch, M.; Chan, Y-D; Christofferson, C. D.; Collar, Juan I.; Combs, D. C.; Detwiler, J.A.; Doe, P. J.; Efremenko, Yuri; Egorov, V.; Ejiri, H.; Elliott, S. R.; Esterline, J.; Fast, J.E.; Fields, N.; Finnerty, P.; Gehman, V. M.; Giovanetti, G. K.; Green, M. P.; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, R.; Hoppe, E.W.; Horton, M.; Howard, S.; Howe, M. 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.; Looker, Q.; Luke, P.N.; MacMullin, S.; Martin, R.D.; Merriman, J. H.; Miller, M. L.; Mizouni, L.; Orrell, John L.; Overman, N. R.; Perumpilly, G.; Phillips II, D. G.; et al.

    2013-01-01

    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. Experiments that operate germanium detectors with a very low energy threshold may benefit from the methods presented herein.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Infusing Stretch Goal Requirements into the Constellation Program

    NASA Technical Reports Server (NTRS)

    Lee, Young H.; Galpin, Roger A.; Ingoldsby, Kevin

    2008-01-01

    In 2004, the Vision for Space Exploration (VSE) was announced by the United States President's Administration in an effort to explore space and to extend a human presence across our solar system. Subsequently, the National Aeronautics and Space Administration (NASA) established the Exploration Systems Mission Directorate (ESMD) to develop a constellation of new capabilities, supporting technologies, and foundational research that allows for the sustained and affordable exploration of space. Then, ESMD specified the primary mission for the Constellation Program to carry out a series of human expeditions, ranging from Low Earth Orbit (LEO) to the surface of Moon, Mars, and beyond for the purposes of conducting human exploration of space. Thus, the Constellation Program was established at the Lyndon B. Johnson Space Center (JSC) to manage the development of the flight and ground infrastructure and systems that can enable continued and extended human access to space. Constellation Program's "Design Objectives" call for an early attention to the program's life cycle costs management through the Program's Need, Goals, and Objectives (NGO) document, which provides the vision, scope, and key areas of focus for the Program. One general policy of the Constellation Program, found in the Constellation Architecture Requirements Document (CARD), states: "A sustainable program hinges on how effectively total life cycle costs are managed. Developmental costs are a key consideration, but total life cycle costs related to the production, processing, and operation of the entire architecture must be accounted for in design decisions sufficiently to ensure future resources are available for ever more ambitious missions into the solar system....It is the intent of the Constellation Program to aggressively manage this aspect of the program using the design policies and simplicity." To respond to the Program's strong desire to manage the program life cycle costs, special efforts were

  14. CP Stars - probing stellar surface structure with BRITE Constellation

    NASA Astrophysics Data System (ADS)

    Lüftinger, T.; Weiss, W. W.

    2008-01-01

    More than 170 chemically peculiar (CP) stars will be observable by BRITE Constellation. These stars host a complex interplay of phenomena like strong magnetic fields, chemical diffusion, pulsation and rotation in the same object. Thus they serve as unique stellar laboratories where we can observe the correlation and interaction of these fundamental physical processes. We present here a summary of the unique potentials BRITE Constellation offers to obtain new insights in the atmospheric structure formation and the complex interplay of abundance variations, pulsation and magnetic fields under conditions that could never be reproduced on Earth.

  15. 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.

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

    DOE PAGESBeta

    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.; et al

    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

  17. 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.

  18. 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.

  19. 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,…

  20. Ocean observing satellite study: instrument and satellite constellation architecture options

    NASA Technical Reports Server (NTRS)

    Gerber, A. J.; McGuire, J.; Cunningham, J. D.; Pichel, W. G.

    2002-01-01

    This paper provides: (1) an overview of the set of active and passive instruments identified by the IPO designed to make the ocean measurements including visible and infrared medium and high resolution imagers, radiometers, altimeters, and synthetic aperture radars and (2) the instrument and satellite constellation architecture options studied, and their ability to meet the set of measurement requirements.

  1. The Constellation-X Mission: Science Prospects and Technology Challenges

    NASA Technical Reports Server (NTRS)

    Petre, Robert

    2007-01-01

    This talk will describe the Constellation-X mission. It will present the key scientific goals, relating to strong gravity, dark energy, ultra-dense matter and cosmic structure. The mission configuration will be described. Emphasis will be placed on the design and anticipated implementation of the X-ray mirror system.

  2. 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.

  3. 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

  4. 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

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Constellation Mystic Power, LLC; Supplemental Notice That Initial Market... supplemental notice in the above-referenced proceeding of Constellation Mystic Power, LLC's application...

  5. 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....

  6. 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...

  7. 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.

  8. VISTA - A Constellation for Real Time Regional Imaging

    NASA Astrophysics Data System (ADS)

    Meerman, Max; Boland, Lee; da Silva Curiel, Alex; Sweeting, Martin, , Sir

    2002-01-01

    The role of satellites in medium and high-resolution reconnaissance of the Earth's surface has been well demonstrated in recent years through missions such as Landsat, SPOT, IKONOS, ImageSat and Quickbird. The market for such data products is well served and likely to become more competitive with further very-high-resolution missions. Whereas commercial markets have concentrated on enhancing resolution, the small satellite sector has concentrated on reducing the cost of data products, and the development of systems providing niche services. One such EO requirement that can be well met by smaller satellites is the need for higher temporal resolution, as this typically requires a large number of satellites to operate as a constellation - thus far financially impractical using conventional EO satellites. Surrey is currently engaged in building its first constellation that will provide daily global coverage at moderate resolution (32-metre GSD and 600km swath) in three spectral bands. Targeted at providing timely quick-look data products for disaster mitigation and monitoring, the constellation comprises 7 satellites in a single orbital plane. Each satellite has a wide swath so that successive satellites progressively cover the entire globe in a single day. The Vista constellation takes this concept a step further, and is proposed for applications requiring near-continuous surveillance of regional activity. By introducing a multiple plane constellation of small Earth observation satellites, it is possible to monitor continuously selected regions anywhere on the globe. The paper describes the system trades and outlines the scope of the performance that could be obtained from such a system. A cost model illustrates that the balance between launch and space segment costs must be reached by considering suitable replacement strategies, and that the system is highly sensitive to requirement creep. Finally, it is shown that the use of cost effective, small satellites leads to

  9. 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.

  10. 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

  11. 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

  12. 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. PMID:27101787

  13. 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.

  14. 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

  15. 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.

  16. Life Support Requirements and Challenges for NASA's Constellation Program

    NASA Technical Reports Server (NTRS)

    Carasquillo, Robyn

    2007-01-01

    NASA's Constellation Program, which includes the mission objectives of establishing a permanently-manned lunar Outpost, and the exploration of Mars, poses new and unique challenges for human life support systems that will require solutions beyond the Shuttle and International Space Station state of the art systems. In particular, the requirement to support crews for 210 days duration at the lunar outpost with limited resource resupply capability wilt require closed-loop regenerative life support systems with minimal expendables. Planetary environmental conditions such as lunar dust and extreme temperatures, as well as the capability to support frequent and extended-duration EVA's will be particularly challenging. This presentation will summarize the key program and mission life support requirements for the Constellation Program and the unique challenges they present for technology and architecture development.

  17. 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.

  18. Global communication using a constellation of low earth meridian orbits

    NASA Astrophysics Data System (ADS)

    Oli, P. V. S.; Nagarajan, N.; Rayan, H. R.

    1993-07-01

    The concept of 'meridian orbits' is briefly reviewed. It is shown that, if a satellite in the meridian orbit makes an odd number of revolutions per day, then the satellite passes over the same set of meridians twice a day. Satellites in such orbits pass over the same portion of the sky twice a day and every day. This enables a user to adopt a programmed mode of tracking, thereby avoiding a computational facility for orbit prediction, look angle generation, and auto tracking. A constellation of 38 or more satellites placed in a 1200 km altitude circular orbit is favorable for global communications due to various factors. It is shown that appropriate phasing in right ascension of the ascending node and mean anomaly results in a constellation, wherein each satellite appears over the user's horizon one satellite after another. Visibility and coverage plots are provided to verify the continuous coverage.

  19. Comet Hale-Bopp in the constellation Andromeda

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Comet Hale-Bopp was photographed in the constellation Andromeda by George Shelton, photographer for The Bionetics Corp., at 8:14 p.m. on March 31, 1997, from Merritt Island, Florida, close to the Kennedy Space Center. During this 24-hour period, Comet Hale- Bopp is making its closest approach to the Sun.

  20. 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.

  1. 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

  2. SCARF - The Swarm Satellite Constellation Application and Research Facility

    NASA Astrophysics Data System (ADS)

    Olsen, Nils

    2014-05-01

    Swarm, a three-satellite constellation to study the dynamics of the Earth's magnetic field and its interactions with the Earth system, has been launched in November 2013. The objective of the Swarm mission is to provide the best ever survey of the geomagnetic field and its temporal evolution, which will bring new insights into the Earth system by improving our understanding of the Earth's interior and environment. In order to take advantage of the unique constellation aspect of Swarm, considerably advanced data analysis tools have been developed. Scientific users will also benefit significantly from derived products, the so-called Level-2 products, that take into account the features of the constellation. The Swarm SCARF (Satellite Constellation Application and Research Facility), a consortium of several research institutions, has been established with the goal of deriving Level-2 products by combination of data from the three satellites, and of the various instruments. A number of Level-2 data products will be offered by this consortium, including various models of the core and lithospheric field, as well as of the ionospheric and magnetospheric field. In addition, derived parameters like mantle conductivity, thermospheric mass density and winds, field-aligned currents, an ionospheric plasma bubble index, the ionospheric total electron content and the dayside equatorial zonal electrical field will be calculated. This service is expected to be operational for a period of at least 5 years. The present paper describes the Swarm input data products (Level-1b and auxiliary data) used by SCARF, the various processing chains of SCARF, and the Level-2 output data products determined by SCARF.

  3. 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.

  4. Results of the Constellation-X Mission Architecture Study

    NASA Astrophysics Data System (ADS)

    Skinner, M. A.; Stober, J. J.; Miller, C. D.

    1999-09-01

    The Constellation X-ray Mission is a proposed high throughput X-ray spectroscopy mission, scheduled to be planned, designed, constructed, launched, and operated in the coming decade. Constellation-X will provide a factor of nearly 100 increase in sensitivity over current high resolution X-ray spectroscopy missions and, in so doing, will obtain high quality spectra for all classes of X-ray sources over a wide range of luminosity and redshift. Cooperatively with the NASA Goddard Space Flight Center and the Smithsonian Astrophysical Observatory, we have carried out a mission architecture study, consisting of a series of preliminary configuration trades, that considered the mission and payload requirements, launch vehicle capabilities, candidate orbits, costs, and instrument accommodation abilities. We generated a small number of concepts that meet the Constellation-X requirements, and have ranked them based on risk and cost considerations. Our concept for the mission architecture design includes a suite of hard and soft X-ray telescopes, to be launched aboard two Evolved Expendable Launch Vehicles (EELV). A fixed optical bench, fixed solar array, and fixed sunshade accommodate the required telescope focal length, and provide for the cryogenic microcalorimeter detectors, as well as the other X-ray instruments. An L2 orbit provides for the thermal requirements of the detectors, and offers other advantages. Below, we illuminate these and other considerations, with an emphasis on the accommodation of the instruments in the observatory.

  5. 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.

  6. 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. PMID:19340137

  7. 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.

  8. SCARF - The Swarm Satellite Constellation Application and Research Facility

    NASA Astrophysics Data System (ADS)

    Olsen, N.; Alken, P.; Beggan, C.; Chulliat, A.; Doornbos, E.; Floberghagen, R.; Friis-Christensen, E. A.; Hamilton, B.; Hulot, G.; van den IJssel, J.; Kuvshinov, A. V.; Lesur, V.; Luhr, H.; Macmillan, S.; Maus, S.; Olsen, P. H.; Park, J.; Plank, G.; Ritter, P.; Rother, M.; Sabaka, T. J.; Stolle, C.; Thebault, E.; Thomson, A. W.; Tøffner-Clausen, L.; Velimsky, J.; Visser, P. N.

    2011-12-01

    In order to take advantage of the unique constellation aspect of the Swarm mission, considerably advanced data analysis tools will need to be developed. Scientific use of data from the Swarm mission will also benefit significantly from derived products, the so-called Level-2 products, that take into account the features of the constellation. For this reason ESA has established a "Satellite Constellation Application and Research Facility" (SCARF), in the form of a consortium of several research institutions. A number of Level-2 data products will be offered by this consortium, including various models of the core and lithospheric field, as well as of the ionospheric and magnetospheric field. In addition, derived parameters like mantle conductivity, thermospheric mass density and winds, field-aligned currents, an ionospheric plasma bubble index, the ionospheric total electron content and the dayside equatorial zonal electrical field will be calculated. Following the end of the currently running 30-month development phase, this service is expected to be operational for a period of 5 years after the launch of the Swarm Mission, which is scheduled for summer 2012. All of the derived products will be available through the Swarm Payload Data Ground Segment (PDGS), located at ESRIN, the ESA Centre for Earth Observation in Frascati, Italy.

  9. 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).

  10. 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.