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Mysterious quasar casts doubt on black holes - space -

Mysterious quasar casts doubt on black holes - space - | Tout est relatant | Scoop.it
A controversial alternative to black hole theory has been bolstered by observations of an object in the distant universe, researchers say. If their interpretation is correct, it might mean black holes do not exist and are in fact bizarre and compact balls of plasma called MECOs.

Rudolph Schild of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, US, led a team that observed a quasar situated 9 billion light years from Earth. A quasar is a very bright, compact object, whose radiation is usually thought to be generated by a giant black hole devouring its surrounding matter.

A rare cosmological coincidence allowed Schild and his colleagues to probe the structure of the quasar in much finer detail than is normally possible. Those details suggest that the central object is not a black hole. "The structure of the quasar is not at all what had been theorised," Schild told New Scientist.

A black hole, as traditionally understood, is an object with such a powerful gravitational field that even light is not fast enough to escape it. Anything that gets within a certain distance of the black hole's centre, called the event horizon, will be trapped.

A well accepted property of black holes is that they cannot sustain a magnetic field of their own. But observations of quasar Q0957+561 indicate that the object powering it does have a magnetic field, Schild's team says. For this reason, they believe that rather than a black hole, this quasar contains something called a magnetospheric eternally collapsing object (MECO). If so, it would be best evidence yet for such an object.

Flickering clues

The researchers used gravitational lensing to make their close observation of the quasar. This technique exploits rare coincidences that can occur when a galaxy sits directly between a distant object and observers on Earth.

The gravity of the intervening galaxy acts like a lens. As the intervening galaxy's individual stars pass in front of the quasar, this bending varies, making the quasar appear to flicker.

Carefully scrutinising this flickering allowed the researchers to probe fine details of the quasar's structure that are normally far too small to be resolved by even the most powerful telescopes.
Magnetic sweep

The researchers found that the disc of material surrounding the central object has a hole in it with a width of about 4000 Astronomical Units (1 AU is the distance between the Earth and the Sun). This gap suggests that material has been swept out by magnetic forces from the central object, the researchers say, and must therefore be a MECO, not a black hole.

"I believe this is the first evidence that the whole black hole paradigm is incorrect," says Darryl Leiter of the Marwood Astrophysics Research Center in Charottesville, Virginia, US, who co-authored the study. He says that where astronomers think they see black holes, they are actually looking at MECOs.

According to the MECO theory, objects in our universe can never actually collapse to form black holes. When an object gets very dense and hot, subatomic particles start popping in and out of existence inside it in huge numbers, producing copious amounts of radiation. Outward pressure from this radiation halts the collapse so the object remains a hot ball of plasma rather than becoming a black hole.
Extremely complex

But Chris Reynolds of the University of Maryland, in College Park, US, says the evidence for a MECO inside this quasar is not convincing. The apparent hole in the disc could be filled with very hot, tenuous gas, which would not radiate much and would be hard to see, he says. "Especially if you're looking with an optical telescope, which is how these observations were made, you wouldn't see that gas at all," he told New Scientist.

Leiter says this scenario would leave other things unexplained, however. The observations show that a small ring at the inner edge of the disc is glowing, which is a sign that it has been heated by a strong magnetic field, he says. In Reynolds's scenario, one would expect a much broader section of the disc to be heated, he says.

In any case, says Reynolds, it is difficult to draw conclusions from the team's detailed comparisons of their observations with models of black holes because those models are far from definitive. "We know the accretion of gas into black holes is an extremely complex phenomenon," he says. "We don't know precisely what that would look like."

"It would be truly exciting if there was compelling evidence found for a non-black-hole object in these quasars," Reynolds adds. "I just don't think that this fits."
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Water Vapor Found on Neptune-size Alien Planet

Water Vapor Found on Neptune-size Alien Planet | Tout est relatant | Scoop.it

A Neptune-size planet beyond the solar system has telltale traces of water vapor in its atmosphere, making it the smallest exoplanet known to have the wet stuff yet, scientists say.

Several massive Jupiter-size giants have had the components of their atmosphere examined, but until now, the atmospheres of smaller planets have proved more elusive. In this new study, scientists discovered traces of water on the alien planet HAT-P-11b, which orbits a star 124 light-years from Earth in the constellation Cygnus.

"Water is the most cosmically abundant molecule that we can directly observe in exoplanets, and we expect it to be prevalent in the upper atmospheres of planets at these temperatures," lead author Jonathan Fraine said in an email interview. Fraine, a graduate student at the University of Maryland, worked with a team lead by Drake Deming, also of the University of Maryland. [10 Alien Planets That Might Support Life]

 

"Detecting it is both a confirmation of our theories and revealing for the bulk of the spectrum that we can observe," Fraine told Space.com.

As a planet passes, or transits, between Earth and its sun, it blocks light from the star. The dip in light is how many exoplanets are first found. But these transits also allow astronomers to study the atmospheres of exoplanets. By observing the spectrum of light that passes through an exoplanet’s atmosphere, scientists can determine what it is made up of. [Quiz: Are You an Exoplanet Expert?]

For HAT-P-11b, a planet roughly four times the radius of Earth, that makeup is 90 percent hydrogen, with traces of water vapor. The Neptune-size planet orbits its sun every five days, at a distance that is only one-twentieth of the Earth-sun distance (which is 93 million miles, or 150 million kilometers). As a result, the temperature climbs higher on HAT P-11b than it does on gas giants in the solar system, reaching a sizzling 1,120 degrees Fahrenheit (605 degrees Celsius).

Scientists have been studying the atmospheres of Jupiter-like planets for years, but smaller planets produce a smaller signal that is more challenging to observe. For the new study, researchers examined the atmospheres of four other smaller exoplanets — two roughly the size of Neptune and two smaller super-Earths — but the results were disappointingly featureless.

"We do indeed have the technology — the resolution — to observe Neptune-size exoplanets, and even super-Earths," Fraine said.

But the chemical compositions of the other four planets were blocked by a familiar phenomenon — clouds.

"We've just been seeing a whole lot of nothing," Eliza Kempton, of Grinnell College in Iowa. Kempton models planetary atmospheres but was not involved in the research.

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Un "frère" perdu du Soleil retrouvé par des astronomes

Un "frère" perdu du Soleil retrouvé par des astronomes | Tout est relatant | Scoop.it
Des astronomes ont identifié un "frère" du Soleil : une étoile qui est probablement née du même nuage de gaz et de poussière que notre étoile.

En pointant une lunette astronomique bon marché en direction de la constellation d'Hercule, il vous sera possible d'y apercevoir l'un des « frères" de notre Soleil, non loin de l'étoile Vega. Baptisée HD 162826, cette étoile est en effet très probablement née dans la même nébuleuse de gaz de poussière que notre Soleil, il y a quelques 4,6 milliards d'années.

Détectée par une équipe d'astronomes emmenée par Ivan Ramirez (Université du Texas, États-Unis), l'étoile HD 162826 est située à 110 années-lumière de la Terre, et possède une masse supérieure de 15% à celle de notre Soleil.

L'étoile HD 162826 fait partie d'un groupe de 30 étoiles qui étaient étudiées depuis plusieurs années par les astronomes, car présentant des caractéristiques suggérant qu'elles pouvaient provenir du même nuage de gaz et de poussière que notre Soleil. Et c'est en passant au crible ces différentes caractéristiques à l'aide du télescope Harlan J. Smith de l'observatoire McDonald (Fort Davis, Etats-Unis), comme l'analyse de leur trajectoire orbitale au sein de notre galaxie ou l'étude de leur composition chimique, que l'astronome Ivan Ramirez et ses collègues sont parvenus à la conclusion que, parmi toutes ces candidates, l'étoile HD 162826 était manifestement l'un des "frères" perdus du Soleil.

Selon Ivan Ramirez, il n'est pas interdit de penser que les étoiles qui sont issues de la même nébuleuse de gaz et de poussière que notre Soleil, comme l'étoile HD 162826, ont une (petite) probabilité d'acceuillir des planètes abritant la vie. En effet, lorsque le Soleil et ses "frères" étaient en train de se former au sein de cette nébuleuse, des fragments rocheux portant potentiellement en leur sein des ingrédients nécessaires à la vie pourraient avoir voyagé d'une étoile à l'autre (et parmi elles, notre Soleil). Par conséquent, il est possible d'émettre l'hypothèse que ces ingrédients nécessaires à la vie, qui ont ensemencé la Terre, se sont également répandu au sein de ces autres étoiles nées avec le Soleil, et donc aussi au sein de leurs planètes.

Cette étude sera prochainement publiée dans la revue Astrophysical Journal sous le titre "Elemental Abundances of Solar Sibling Candidates". Ses références sont pour l'instant consultables sur le serveur de prépublication ArXiv : "Elemental Abundances of Solar Sibling Candidates".

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700 000 débris spatiaux tournent au-dessus de nos têtes

700 000 débris spatiaux tournent au-dessus de nos têtes | Tout est relatant | Scoop.it

Il y a 

Il y a eu la conquête spatiale et s'en est suivi la pollution de l'espace. Aujourd'hui, les scientifiques estiment à 700 000 le nombre de débris de plus d'un centimètre - 135 millions le nombre de débris de plus d'un millimètre - que l'homme a envoyés dans l'espace et qui tournent toujours au-dessus de nos têtes. Des débris potentiellement dangereux pour tous les nouveaux équipements spatiaux. Les récupérer est donc devenu un enjeu majeur pour les agences spatiales. Et les représentants d'une dizaine d'entre elles se retrouvent, ce lundi 12 mai, à Pékin, pour en débattre.

Un centimètre, ça peut paraître bien petit comme taille, mais dans l'espace, c'est loin d'être anodin. En orbite basse, des débris de cette taille-là ont la même énergie cinétique qu'une grosse berline lancée à 130 km/h. Alors si l'un d'entre eux venait à toucher un satellite en activité ou la station spatiale internationale, les dégâts pourraient être considérables. Et s'il en existe des biens plus gros - comme un satellite européen de 8 tonnes tournant à 25 000 kilomètres/heure - ce sont finalement les petits qui sont le plus dangereux, car le plus difficilement repérable, depuis la Terre comme depuis l'espace.

Avec 700 000 débris de plus d'un centimètre, la probabilité d'une collision n'est pas une hypothèse absurde. Le risque de perte d'un satellite est aujourd'hui de 5% : trop élevé aux yeux des agences spatiales.

Reste que faire le ménage dans l'espace n'est pas une tâche aisée. Pour les plus petits, il est possible d'envisager la destruction par laser depuis la Terre. Pour les autres, l'hypothèse de travail la plus avancée est celle d'un câble électrodynamique installé sur une navette ou une capsule. En donnant une décharge aux débris, il infléchirait leur trajectoire accélérant leur retour dans l'atmosphère et donc leur désintégration.

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ST - 2014 : Planck dévoile l’empreinte magnétique de notre Galaxie - CNES

ST - 2014 : Planck dévoile l’empreinte magnétique de notre Galaxie - CNES | Tout est relatant | Scoop.it
Le champ magnétique de la Voie Lactée vient d’être révélé dans une nouvelle carte livrée par la mission Planck de l’Agence spatiale européenne (ESA). Cette image est issue des 1eres observations sur l’ensemble du ciel de la lumière « polarisée » émise par la poussière interstellaire de notre galaxie. De nombreux chercheurs et ingénieurs du CNRS, du CEA, du CNES et des universités participent à la mission Planck qui continue sa moisson de résultats. Ces analyses viennent d’être soumises, dans 4 articles, à la revue Astronomy & Astrophysics.

La lumière est une forme d'énergie qui nous est très familière même si certaines de ses propriétés ne sont pas facilement accessibles. L'une d'entre elles - la polarisation - est une source d'informations pour les chercheurs. Dans l'espace, la lumière émise par les étoiles, le gaz ou la poussière peut être polarisée de plusieurs façons. En mesurant cette polarisation, les astronomes peuvent étudier les processus physiques qui sont à son origine, en particulier les propriétés des champs magnétiques dans le milieu interstellaire de notre Galaxie.

 

La carte présentée ici a été obtenue en utilisant des détecteurs du satellite Planck, agissant un peu à la manière des lunettes de soleil polarisées, en version astronomique. Les tourbillons, boucles et arches de cette image tracent la structure du champ magnétique de notre Galaxie. Cette image dévoile l'organisation à grande échelle d'une partie du champ magnétique galactique. La bande sombre correspond au plan galactique : l'émission polarisée y est particulièrement intense. La structure générale révèle un motif régulier où les lignes du champ magnétique sont majoritairement parallèles au plan de la Voie Lactée.

Les observations révèlent également des variations de la direction de polarisation dans les nuages de matière proches du Soleil vus de part et d'autre de la bande sombre. Celles-ci témoignent de changements de la direction du champ magnétique dont les astrophysiciens étudient l'origine.

Les zones à haute latitude galactique ont été masquées. Le signal y est plus faible et un travail supplémentaire est requis pour mesurer et séparer la polarisation de notre Galaxie de celle du rayonnement fossile micro-onde.

 

Au-delà de notre galaxie

L'intensité du rayonnement fossile de l'Univers a été cartographiée avec une précision sans précédent par Planck et aujourd'hui les chercheurs scrutent ces données pour mesurer la polarisation de ce rayonnement. C'est l'un des objectifs principaux de la mission Planck car cette polarisation pourrait révéler la présence d'ondes gravitationnelles primordiales générées juste après la naissance de l'Univers.

En mars 2014, les scientifiques de la collaboration BICEP2 ont annoncé la première détection d'un tel signal dans les données collectées par un télescope au sol observant une petite fraction du ciel (1%) à une seule fréquence. Leur résultat repose sur l'hypothèse que la polarisation de l'émission d'avant-plan de notre galaxie est négligeable dans cette région.

D'ici la fin de l'année 2014, la collaboration Planck livrera ses données obtenues à partir des observations du ciel complet dans les sept bandes en fréquence où les détecteurs sont sensibles à la polarisation de la lumière. Ces mesures multifréquences devraient permettre aux astrophysiciens d'estimer et de séparer le signal polarisé primordial et le signal d'avant-plan de notre Galaxie.

Cette étude permettra une investigation bien plus détaillée du début de l'histoire du cosmos, depuis son expansion quand l'Univers était âgé d'une toute petite fraction de seconde jusqu'à la naissance des premières étoiles, plusieurs centaines de millions d'années plus tard.

Un niveau de détail encore amélioré avec Pilot

En 2015, un ballon stratosphérique géant du CNES emportera à près de 40 km d’altitude une expérience de près d’une tonne développée par le CNRS, le CEA et le CNES, avec des contributions des universités de Rome et de Cardiff. Cette expérience, appelée Pilot, cartographiera l’émission polarisée du disque de notre galaxie avec des détails encore plus fins (près d’un vingtième de degrés) à une longueur d’onde complémentaire de celles de Planck.

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L'américain SpaceX lancera un satellite construit par Astrium

L'américain SpaceX lancera un satellite construit par Astrium | Tout est relatant | Scoop.it

Astrium, la branche spatiale d'EADS, va faire appel au concurrent de sa fusée Ariane, le lanceur Falcon 9 de l'américain SpaceX, pour lancer un satellite de surveillance allemand.

Dans le contrat signé ce 18 septembre par le spécialiste des technologies spatiales Astrium avec l'allemand OHB, ce n'est pas le montant de 344 millions d'euros qui marque les esprits, mais plutôt le lanceur choisi par la filiale de l'européen EADS pour mettre en orbite le futur satellite de surveillance de l'armée allemande.

Astrium, maître d'oeuvre de la fusée européenne Ariane, a confié à l'AFP "avoir choisi" Falcon 9, le lanceur rival développé par l'américain SpaceX qui fera ses débuts cet automne, car il est est "plus adapté à la demande du client".

C'est la première fois qu'Astrium fait appel à SpaceX. Un porte-parole a expliqué à l'AFP que le satellite du projet allemand SARah, qu'il va développer, fabriquer et lancer pour le compte de l'entreprise OHB System (qui construit les deux autres satellites du pojet SARAh) selon les termes du contrat, sera "trop petit pour être lancé seul sur Ariane 5", et placé sur orbite basse et non sur l'orbite géostationnaire habituelle pour Ariane.

Le contrat signé entre Astrium et OHB couvre également "la mise en place de tous les composants nécessaires au segment sol et d’une chaîne de traitement des images, de la commande à la transmission, totalement opérationnelle à fin 2019", précise le communiqué.

Dans le même temps, Astrium a annoncé dans un autre communiqué avoir signé avec Arianespace un accord pour engager la production de 18 fusées Ariane 5 ECA supplémentaires, qui seront lancées à partir de 2017. Elles s'ajoutent aux 35 lanceurs déjà commandés en 2009 par le spécialiste européen du transport spatial.

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ALMA observe de très près la dramatique naissance d'une étoile

ALMA observe de très près la dramatique naissance d'une étoile | Tout est relatant | Scoop.it

 

Des astronomes utilisant le Grand Réseau d’Antennes (sub-)millimétrique de l'Atacama (ALMA) ont obtenu une formidable vue rapprochée de la matière s'échappant d'une étoile nouvellement formée. En observant la lueur émise par les molécules de monoxyde de carbone dans un objet baptisé Herbig-Haro 46/47, ils ont découvert que ses jets sont bien plus énergétiques que prévu. Les nouvelles images très détaillées ont également révélé l'existence d'un jet encore inconnu pointant dans une direction radicalement différente.

Les jeunes étoiles constituent de vigoureux objets qui éjectent la matière à des vitesses proches du million de kilomètres par heure. Lorsque cette matière entre en interaction avec le gaz environnant, elle émet une lueur, créant par là-même un objet de type Herbig-Haro [1]. Herbig Haro 46/47, qui se situe à environ 1400 années-lumière de la Terre dans la constellation australe de Véla (Les Voiles), en constitue un formidable exemple. Cet objet a été étudié au moyen du réseau ALMA alors que ce dernier était encore en phase de construction, bien avant qu'il ne soit doté de l'intégralité des antennes qui le constituent aujourd'hui, donc.

Les nouvelles images révèlent le détail de deux jets, l'un se déplaçant en direction de la Terre, l'autre s'en éloignant. Le second jet était quasiment invisible sur les images antérieures acquises dans le domaine visible, en raison de l'obscurcissement généré par les nuages de poussière entourant l'étoile nouvellement formée. ALMA n'a pas seulement fourni des images dotées d'une meilleure résolution – comparée aux instruments plus anciens, il a également permis aux astronomes de mesurer la vitesse à laquelle la matière incandescente se déplace dans l'espace.

Ces nouvelles observations de Herbig Haro 46/47 révèlent que certains des matériaux éjectés sont dotés de vitesses bien plus élevées que celles mesurées auparavant. Cela signifie que le gaz qui s'échappe transporte bien plus d'énergie et de moment cinétique que nous le pensions.

Le leader de l'équipe et premier auteur de cette nouvelle étude, Héctor Arce (Université de Yale, Etats-Unis), nous explique que « l'extrême sensibilité d'ALMA permet la détection de caractéristiques auparavant invisibles dans cette source, tel ce jet de gaz très rapide. Il semble également qu'il s'agisse là d'un cas d'école : un modèle simple au sein duquel le jet moléculaire résulte d'un vent étendu en provenance de la jeune étoile. »

Les observations ont requis un temps d'observation de cinq heures seulement – bien qu'ALMA ait été encore en phase de construction à cette époque. Des observations de semblable qualité auraient requis un temps d'observation dix fois plus élevé avec d'autres télescopes.

« Le niveau de détail qui caractérise les images de Herbig Haro 46/47 est stupéfiant. D'autant plus impressionnant que ces images ont été acquises lors de la première phase d'exploitation scientifique d'ALMA. Dans l'avenir, ALMA procurera des images encore meilleures que celles-ci en une fraction de temps » ajoute Stuartt Corder (Observatoire Unifié ALMA, Chili), l'un des co-auteurs de cette nouvelle étude.

Diego Mardones (Université du Chili), autre co-auteur de cette étude, souligne que « ce système est semblable aux étoiles de faible masse les plus isolées en cours de formation, sur le point de naître donc. Ce qui fait l'originalité de ce système : le jet impacte le nuage d'un côté de la jeune étoile et s'échappe du nuage de l'autre côté. Il constitue donc un formidable objet d'étude de l'impact des vents stellaires sur le nuage à partir duquel la nouvelle étoile s'est formée. »

La résolution et la sensibilité qui caractérisent ces images acquises par ALMA ont également permis à l'équipe de découvrir l'existence d'un jet inconnu, provenant selon toute vraisemblance d'un compagnon de faible masse de la jeune étoile. Ce jet secondaire figure dans une direction perpendiculaire à l'objet principal et semble creuser son propre chemin au sein du nuage environnant.

Héctor Arce concludes that "ALMA has made it possible to detect features in the observed outflow much more clearly than previous studies. This shows that there will certainly be many surprises and fascinating discoveries to be made with the full array. ALMA will certainly revolutionise the field of star formation!"

Héctor Arce conclut ainsi : « ALMA a permis de déterminer les caractéristiques du jet de matière observé bien plus efficacement que toute étude antérieure. Cela augure de nombreuses surprises et de fascinantes découvertes à venir au moyen du réseau complet. ALMA révolutionnera sans aucun doute notre connaissance des processus de formation des étoiles ! »

Notes

[1] Les astronomes George Herbig et Guillermo Haro ne furent pas les découvreurs de l'un de ces objets qui portent à présent leurs noms, mais ils furent les premiers à étudier dans le détail le spectre de ces étranges objets. Ils ont découvert qu'il ne s'agissait pas de simples nuages de gaz et de poussières qui réfléchissaient la lumière, ou brillaient sous l'effet de la lumière ultraviolette en provenance de jeunes étoiles, mais qu'ils constituaient une nouvelle classe d'objets associés à des chocs créés par la matière éjectée à des vitesses élevées dans les régions de formation d'étoiles.

Plus d'informations

ALMA (Atacama Large Millimeter/submillimeter Array) est un équipement international pour l'astronomie. Il est le fruit d'un partenariat entre l'Europe, l'Amérique du Nord et l'Asie de l'Est en coopération avec la République du Chili. ALMA est financé en Europe par l'ESO (Observatoire Européen Austral), en Amérique du Nord par la NSF (Fondation Nationale de la Science) en coopération avec le NRC (Conseil National de la Recherche au Canada) et le NSC (Conseil National de la Science à Taïwan), en Asie de l'Est par les Instituts Nationaux des Sciences Naturelles (NINS) du Japon avec l'Academia Sinica (AS) à Taïwan. La construction et les opérations d'ALMA sont pilotées par l'ESO pour l'Europe, par le National Radio Astronomy Observatory (NRAO), dirigé par Associated Universities, Inc. (AUI) pour l'Amérique du Nord et par le National Astronomical Observatory of Japan (NAOJ) pour l'Asie de l'Est. L'Observatoire commun ALMA (JAO pour Joint ALMA Observatory) apporte un leadership et un management unifiés pour la construction, la mise en service et l'exploitation d'ALMA.

Ce travail de recherche a fait l'objet d'un article intitulé « ALMA Observations of the HH 46/47 Molecular Outflow » par Héctor Arce et al, à paraître dans la revue Astrophysical Journal.

L'équipe est composée de Héctor G. Arce (Université de Yale, New Haven, Etats-Unis), Diego Mardones (Université du Chili, Santiago, Chili), Stuartt A. Corder (Observatoire Unifié ALMA, Santiago, Chili), Guido Garay (Université du Chili), Alberto Noriega-Crespo (Centre de Traitement et d'Analyse Infrarouge, Institut de Technologie de Californie, Pasadena, Etats-Unis) et Alejandro C. Raga (Institut des Sciences Nucléaires, Mexique).

L'ESO est la première organisation intergouvernementale pour l'astronomie en Europe et l'observatoire astronomique le plus productif au monde. L'ESO est soutenu par 15 pays : l'Allemagne, l'Autriche, la Belgique, le Brésil, le Danemark, l'Espagne, la Finlande, la France, l'Italie, les Pays-Bas, le Portugal, la République Tchèque, le Royaume-Uni, la Suède et la Suisse. L'ESO conduit d'ambitieux programmes pour la conception, la construction et la gestion de puissants équipements pour l'astronomie au sol qui permettent aux astronomes de faire d'importantes découvertes scientifiques. L'ESO joue également un rôle de leader dans la promotion et l'organisation de la coopération dans le domaine de la recherche en astronomie. L'ESO gère trois sites d'observation uniques, de classe internationale, au Chili : La Silla, Paranal et Chajnantor. À Paranal, l'ESO exploite le VLT « Very Large Telescope », l'observatoire astronomique observant dans le visible le plus avancé au monde et deux télescopes dédiés aux grands sondages. VISTA fonctionne dans l'infrarouge. C'est le plus grand télescope pour les grands sondages. Et, le VLT Survey Telescope (VST) est le plus grand télescope conçu exclusivement pour sonder le ciel dans la lumière visible. L'ESO est le partenaire européen d'ALMA, un télescope astronomique révolutionnaire. ALMA est le plus grand projet astronomique en cours de réalisation. L'ESO est actuellement en train de programmer la réalisation d'un télescope européen géant (E-ELT pour European Extremely Large Telescope) de la classe des 39 mètres qui observera dans le visible et le proche infrarouge. L'E-ELT sera « l'œil le plus grand au monde tourné vers le ciel ».

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LADEE: NASA's Next Mission to the Moon

LADEE: NASA's Next Mission to the Moon | Tout est relatant | Scoop.it

NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) — pronounced "laddie," not "lady" — is set to launch to the moon in early September 2013.

The 844-pound (383 kilograms) spacecraft is designed to orbit the moon, investigating lunar dust, the lunar atmosphere and conditions near the moon's surface, NASA officials have said.

"While we know Earth's atmosphere has oxygen, we do not know what comprises the moon's atmosphere," NASA officials wrote in a fact sheet. "To help us understand what it contains, LADEE will dip into the lunar atmosphere, and instruments onboard the spacecraft will send detailed measurements to scientists to analyze on Earth." [Photos: NASA's LADEE Moon Dust Mission in Pictures]

 

 

Lunar atmosphere?

The moon's atmosphere is much thinner than Earth's. Scientists suspect that the lunar atmosphere is about 1/100,000th the density of Earth's; they therefore consider it a vacuum.

Because the atmosphere is so thin, temperatures reach 273 degrees Fahrenheit (134 degrees Celsius) on the sunny side of the moon, but the temperature can get as cold as -243 degrees Fahrenheit (-153 degrees Celsius) on the far side of the moon.

The moon's atmosphere can be compared to the fringes of Earth's atmosphere, the area of space where the International Space Station orbits, NASA officials wrote. Scientists also suspect that the moon's atmosphere could be analogous to the atmospheres of other relatively small planetary bodies throughout the solar system.

Following in lunar footsteps

LADEE is the latest in a long line of probes NASA has sent to the moon.

The space agency's Pioneer 4 completed the first successful American flyby of the moon in 1959. The Soviet spacecraft Luna 1 successfully flew by the moon a few months earlier. [How NASA's LADEE Spacecraft Works (Infographic)]

After sending various spacecraft to the natural satellite throughout the 1960s and 1970's, and successfully landing a manned vessel on the lunar surface in 1969, NASA didn't send another spacecraft to the moon until the Clementine orbiter in 1994.

In 2011, the Lunar Reconnaissance Orbiter sent back the most high-resolution moon map ever constructed.

That same year, the twin GRAIL (Gravity Recovery And Interior Laboratory-A) spacecraft launched. The two probes, responsible for investigating the structure of the lunar interior, were purposefully crashed into the moon in December 2012.

LADEE's Science

The LADEE spacecraft comes equipped with three science instruments and a technology demonstration:

Ultraviolet and Visible Light Spectrometer – This instrument will analyze the light signatures of materials around the moon to understand the composition of the satellite's atmosphere.Lunar Dust Experiment – This instrument will collect and analyze moon dust in the atmosphere. The instrument could also help NASA scientists solve a mystery, NASA officials wrote in a facts sheet: "Was lunar dust, electrically charged by solar ultraviolet light, responsible for the pre-sunrise horizon glow that the Apollo astronauts saw?"Neutral Mass Spectrometer – The spectrometer will look for variations in the lunar atmosphere while the moon is in different orbits and various space environments, according to NASA officials.Lunar Laser Communications Demonstration – For this technology demonstration, LADEE will use lasers (and not radio waves, like other spacecraft that have flown beyond close Earth orbit have used) to communicate with controllers on Earth. This could allow the spacecraft to communicate at broadband speeds with the ground.A history-making launch

The LADEE launch will be the first deep-space mission to launch from NASA's Goddard Space Flight Center's Wallops Flight Facility in Virginia. This mission also marks the first time a payload has been launched aboard a U.S. Air Force Minotaur V rocket integrated by Orbital Sciences Corp., NASA officials have said.

Once launched, the probe will take about 30 days to get to the moon; LADEE will then go through a checkout period for another 30 days. After that, the probe is scheduled to conduct 100 days of science operations.

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Wow! Curiosity Rover Captures 2 Mars Moons Together In Stunning NASA Video

Wow! Curiosity Rover Captures 2 Mars Moons Together In Stunning NASA Video | Tout est relatant | Scoop.it
Curiosity snapped the 41 images that comprise the 30-second video on Aug. 1, becoming the first robot ever to capture a view of the two satellites — called Phobos and Deimos — eclipsing each other from the Martian surface.

 

The new Curiosity video has plenty of scientific value in addition to its gee-whiz appeal, officials said. For example, researchers are studying the images to refine their knowledge of the orbits of Phobos and Deimos, both of which appear to be captured asteroids. [Watch Curiosity's video of the Martian moon eclipse]

 

"The ultimate goal is to improve orbit knowledge enough that we can improve the measurement of the tides Phobos raises on the Martian solid surface, giving knowledge of the Martian interior," Mark Lemmon of Texas A&M University said in a statement.

"We may also get data good enough to detect density variations within Phobos and to determine if Deimos' orbit is systematically changing," added Lemmon, who is a co-investigator for Curiosity's Mastcam instrument, which took the pictures using its telephoto lens.

Phobos' orbit is taking it closer to the surface of Mars very slowly, researchers said, while Deimos may gradually be getting farther and farther away from the planet.

Phobos is just 14 miles (22 kilometers) wide on average, while Deimos is even smaller. But Curiosity was able to spot both of them because they orbit quite close to the Red Planet's surface — 3,700 miles (6,000 km) in Phobos' case and 12,470 miles (20,070 km) for Deimos.

Earth's moon is gigantic compared to Phobos and Deimos, with a diameter of about 2,160 miles (3,475 km). But our planet's natural satellite orbits much farther away — its average distance is 239,000 miles (384,600 km) — so Phobos appears half as big in the sky to Curiosity as Earth's moon does to human skywatchers, NASA officials said.

The 1-ton Curiosity rover landed on Mars on Aug. 5, 2012 to determine if the Red Planet could ever have supported microbial life. The six-wheeled robot has already achieved that mission goal, finding that a site called Yellowknife Bay was indeed habitable billions of years ago.

Curiosity is now embarked upon a long drive to the foothills of the huge Mount Sharp, whose many layers hold a record of the Red Planet's changing environmental conditions over time. Mission scientists want Curiosity to read that history like a book as it climbs up through the mountain's lower reaches.

Curiosity deputy project scientist Ashwin Vasavada, of NASA's Jet Propulsion Laboratory in Pasadena, Calif., will discuss the rover's first year on Mars tonight (Aug. 15) during a talk at JPL. You can watch the presentation, which begins at 10 p.m. EDT (0200 GMT Aug. 16), live here on SPACE.com, courtesy of NASA and JPL.

 

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Pink Alien Planet Is Smallest Photographed Around Sun-Like Star

Pink Alien Planet Is Smallest Photographed Around Sun-Like Star | Tout est relatant | Scoop.it

Astronomers have snapped a photo of a pink alien world that's the smallest yet exoplanet found around a star like our sun.

The alien planet GJ 504b is a colder and bluer world than astronomers had anticipated and it likely has a dark magenta hue, infrared data from the Subaru Telescope in Hawaii revealed.

"If we could travel to this giant planet, we would see a world still glowing from the heat of its formation with a color reminiscent of a dark cherry blossom, a dull magenta," study researcher Michael McElwain, of NASA's Goddard Space Flight Center in Greenbelt, Md., said in a statement from the space agency.

 

"Our near-infrared camera reveals that its color is much more blue than other imaged planets, which may indicate that its atmosphere has fewer clouds," McElwain added.

The exoplanet orbits the bright star GJ 504, which is 57 light-years from Earth, slightly hotter than the sun and faintly visible to the naked eye in the constellation Virgo. The star system is relatively young at roughly 160 million years old. (For comparison, Earth's system is 4.5 billion years old).

Though it is the smallest alien world caught on camera around a sun-like star, the gas planet around GJ 504 is still huge — about four times the size of Jupiter. It lies nearly 44 Earth-sun distances from its central star, far beyond the system's habitable zone, and it has an effective temperature of about 460 degrees Fahrenheit (237 Celsius), according to the researchers' estimates.

The exoplanet's features challenge the core-accretion model of planet formation, they study's researchers say. Under this widely accepted theory, asteroid and comet collisions produce a core for Jupiter-like planets and when they gets massive enough, their gravitational pull draws in gas from the gas-rich disk of debris that circles their young star. But this model doesn't explain the formation of planets like GJ 504b that are far away from their parent star.

"This is among the hardest planets to explain in a traditional planet-formation framework," study researcher Markus Janson, a Hubble postdoctoral fellow at Princeton University in New Jersey, said in a statement. "Its discovery implies that we need to seriously consider alternative formation theories, or perhaps to reassess some of the basic assumptions in the core-accretion theory."

The discovery of GJ 504b was part of a larger survey, the Strategic Exploration of Exoplanets and Disks with Subaru or SEEDS program, which seeks to explain how planetary systems come together by looking at star systems of many sizes and ages with images at near-infrared wavelengths.

Direct imaging can help scientists measure an alien planet's luminosity, temperature, atmosphere and orbit, but it's difficult to detect faint planets next to their bright parent stars. The study's leader, Masayuki Kuzuhara of the Tokyo Institute of Technology, said the task is "like trying to take a picture of a firefly near a searchlight."

Two of the Subaru Telescope's tools in particular — the High Contrast Instrument for the Subaru Next Generation Adaptive Optics and the InfraRed Camera and Spectrograph — help scientists tease out light from these faint exoplanet sources.

 

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Kilonova: Dead-Star Crashes May Spark Mysterious Cosmic Explosions

Kilonova: Dead-Star Crashes May Spark Mysterious Cosmic Explosions | Tout est relatant | Scoop.it

Cataclysmic crashes involving black holes and ultradense neutron stars may explain the briefest of the most powerful explosions in the universe, scientists say.

 

NASA scientists are calling the new type of short, but intense, cosmic collision and conflagration a "kilonova," an explosion so powerful it is 1,000 times stronger than a typical star explosion, called a nova. Such events have long been predicted by astronomers, but never seen until now, researchers said. The discovery could shed light on the origin of heavy elements such as gold and platinum, they added.

 

Gamma-ray bursts are the most intense outbursts ever detected, giving off as much energy in an instant as our sun will beam out during its entire 10-billion-year lifetime. A nearby burst directed at Earth could easily cause a mass extinction, researchers say. [See more photos of the "kilonova" gamma-ray-burst explosion]

 

There are two kinds of gamma-ray bursts — ones that are longer-lived, lasting more than two seconds, and less common short-lived ones, lasting about two seconds or less.

 

Scientists have suggested these brief gamma-ray bursts might be caused by cataclysmic mergers of incredibly dense cosmic bodies — either two neutron stars (the tiny remnants of exploded stars) or a neutron star and a black hole. However, they lacked evidence until now.

 

 

 

 

Astronomer Nial Tanvir at the University of Leicester in England and his colleagues analyzed the short gamma-ray burst GRB 130603B, which exploded about 4 billion light-years away on June 3. NASA's Swift satellite measured it as 0.18 seconds long, while NASA's Wind spacecraft determined that it lasted only 0.09 seconds.

 

The mergers of dense cosmic bodies that are thought to cause short gamma-ray bursts can also blast out neutron-rich gas that rapidly generates heavy elements such as gold and platinum, scientists say. These "r-process" elements can undergo radioactive decay and release an enormous amount of energy — 1,000 times or so that given off by stellar explosions such as novas. These powerful events are thus known as "kilonovas" ("kilo" means "thousand" in Greek).

NASA's Hubble Space Telescope revealed that the near-infrared afterglow that accompanied GRB 130603B was the kind one would expect from a kilonova. This is smoking-gun evidence that an explosive merger caused the gamma-ray burst, Tanvir told SPACE.com.

"This is just the first example, and we will have to search for and study others to be completely sure, but it certainly looks right," Tanvir said.

 

It remains uncertain what kind of merger caused this kilonova and gamma-ray burst. The theoretical predictions for these mergers and the behavior of kilonovas "still have many uncertainties, so it is too early to try to distinguish these possibilities," Tanvir said.

 

In the future, the researchers aim to find other examples of kilonovas accompanying short gamma-ray bursts. Tanvir added that future research into kilonovas could shed light on the origin of r-process elements.

 

"The r-process elements are heavy elements whose origin we have long been uncertain about," Tanvir said. "They are not produced in normal stars, and astronomers have generally assumed they must be created in supernovae. However, the calculations suggest supernovae may not be good at creating those elements, so it is possible that kilonovae from merging compact objects may be the primary route in the universe to producing these elements."

 

The scientists detailed their findings online Aug. 3 in the journal Nature.

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Brains of the SLS – Flight Computer enters build phase.

Brains of the SLS – Flight Computer enters build phase. | Tout est relatant | Scoop.it

One of the key technologies on NASA’s new monster rocket, a small box of tricks known as the Flight Computer, is making good process during its developmental phase. With Boeing – main contractor for the Space Launch System (SLS) – deeply involved, a Production Readiness Review (PRR) has provided the green light to enter the build phase.

SLS Flight Computer:

All launch vehicles require the ability to think for themselves, providing real time monitoring and actions.

 

Data on the performance and required tasks for the SLS will be fed both to Orion’s crew, via their displays, and to the controllers on the ground – such as the teams in the Flight Control Room (FCR) at the Johnson Space Center (JSC).

For the SLS, the Flight Computer – a box of electronics and software – will run off the highest processing capability available in a flight avionics computer, developed by upgrading existing systems used in Global Positioning System and communication satellites.

Three Flight Computers will make up SLS’ Flight Computer Operating Group (FCOG).

Boeing, the contractor for the majority of the multi-billion dollar SLS, tasked their teams at their Satellite Systems Division facility in El Segundo to develop the Flight Computer, utilizing their experience with numerous satellite systems.

 

Working alongside the SLS Program Office, engineering and safety personnel participated in the kick-off of Boeing’s Flight Computer (FC) Critical Design Review (CDR) on back in August 22-23, 2012.

“Boeing and NASA personnel reviewed the design of the FC and each of its major sub-components, plans for qualifying the design, manufacturing/delivering units of increasing design maturity/pedigree, and mitigation of risks associated with moving forward with the design. Representatives of SLS Level 2 Flight Software team also attended the review,” according to notes from L2′s SLS rolling development update section.

No major issues were identified, although a risk reduction action was established to accelerate environmental testing. Because Boeing is developing the FC internally, the NASA team have been participating more deeply in the design review process.

 

The first of six SLS Core Stage Flight Computer Engineering Development Units (EDUs) was installed in the SLS Flight Software Development Facility (SDF) back in March 5, 2013.

The EDU is a functionally equivalent unit of the SLS Flight Computer developed by Boeing El Segundo.

“The SLS Flight Software team successfully powered up and performed initial checkout of the EDU, leading to efforts to port prototype SLS flight software to the EDU in order to continue integration and checkout of the EDU,” added the notes.

The flight software was installed in the Software Integration Test Facility at Marshall and tested with other electrical hardware and software. This facility can also run a variety of simulations to evaluate how the vehicle will perform in space.

“SLS will be the most powerful launch vehicle ever built, and it requires the most capable flight software in the history of human spaceflight,” added Todd May, Space Launch System Program manager.

“Having this avionics hardware in place early will allow the NASA SLS team and Boeing to accelerate the flight software development.”

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Il y a de l'eau sur Mercure !

Il y a de l'eau sur Mercure ! | Tout est relatant | Scoop.it
De nouvelles données provenant de la sonde Messenger, en orbite autour de Mercure, indiquent la présence d’importantes quantités de glace d’eau près des pôles de la planète la plus proche du Soleil.

De type tellurique, comme ses consœurs du système solaire interne (Mars, Venus et la Terre), Mercure est la planète la plus proche du Soleil. Conséquence : Il y fait très très chaud…ou très très froid !

Recoins. La température à sa surface s’élève en effet à près de 400°C côté jour mais retombe à -170°C quand elle n’est plus sous le feu solaire. Il existe même près des pôles quelques recoins, au fond de cratères, qui ne reçoivent jamais de lumière et où la température ne dépasse jamais -180°C.

C’est dans ces zones d’ombre que les scientifiques en charge de la mission Messenger, une sonde la Nasa qui s’est satellisée autour de Mercure en 2011, ont découvert d’importantes quantités de glace d’eau.

 

En rouge apparaissent les zones du pôle Nord de Mercure qui ne reçoivent jamais les rayons du Soleil.

NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington/National Astronomy and Ionosphere Center, Arecibo Observatory

L’idée de la présence de glace sur Mercure n’est pas nouvelle. Ces cratères d’impact ont été identifiés dès les années 70 par une première sonde, Mariner 10. Et dans les années 90, les radiotélescopes terrestres ont observé des plaques aux pôles qui reflètent les ondes radio comme de la glace.

Confirmation. Bref, il ne manquait plus qu’une confirmation « in situ » obtenue grâce à l’analyse des données issues des instruments de Messenger notamment du spectromètre neutron. Cette présence de glace d’eau fait l’objet de trois articles publiés dans la revue Science dont l’un est cosigné par un chercheur français, Sylvestre Maurice, du CNRS.

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Hubble Helps Find Smallest Known Galaxy Containing a Supermassive Black Hole

Hubble Helps Find Smallest Known Galaxy Containing a Supermassive Black Hole | Tout est relatant | Scoop.it
Astronomers using data from NASA’s Hubble Space Telescope and ground observation have found an unlikely object in an improbable place — a monster black hole lurking inside one of the tiniest galaxies ever known.

The black hole is five times the mass of the one at the center of our Milky Way galaxy. It is inside one of the densest galaxies known to date — the M60-UCD1 dwarf galaxy that crams 140 million stars within a diameter of about 300 light-years, which is only 1/500th of our galaxy’s diameter.

If you lived inside this dwarf galaxy, the night sky would dazzle with at least 1 million stars visible to the naked eye. Our nighttime sky as seen from Earth’s surface shows 4,000 stars.

The finding implies there are many other compact galaxies in the universe that contain supermassive black holes. The observation also suggests dwarf galaxies may actually be the stripped remnants of larger galaxies that were torn apart during collisions with other galaxies rather than small islands of stars born in isolation.

“We don’t know of any other way you could make a black hole so big in an object this small,” said University of Utah astronomer Anil Seth, lead author of an international study of the dwarf galaxy published in Thursday’s issue of the journal Nature.

Seth’s team of astronomers used the Hubble Space Telescope and the Gemini North 8-meter optical and infrared telescope on Hawaii’s Mauna Kea to observe M60-UCD1 and measure the black hole’s mass. The sharp Hubble images provide information about the galaxy’s diameter and stellar density. Gemini measures the stellar motions as affected by the black hole’s pull. These data are used to calculate the mass of the black hole.

Black holes are gravitationally collapsed, ultra-compact objects that have a gravitational pull so strong that even light cannot escape. Supermassive black holes — those with the mass of at least one million stars like our sun — are thought to be at the centers of many galaxies.

The black hole at the center of our Milky Way galaxy has the mass of four million suns. As heavy as that is, it is less than 0.01 percent of the Milky Way’s total mass. By comparison, the supermassive black hole at the center of M60-UCD1, which has the mass of 21 million suns, is a stunning 15 percent of the small galaxy’s total mass.

“That is pretty amazing, given that the Milky Way is 500 times larger and more than 1,000 times heavier than the dwarf galaxy M60-UCD1,” Seth said.
One explanation is that M60-UCD1 was once a large galaxy containing 10 billion stars, but then it passed very close to the center of an even larger galaxy, M60, and in that process all the stars and dark matter in the outer part of the galaxy were torn away and became part of M60.

The team believes that M60-UCD1 may eventually be pulled to fully merge with M60, which has its own monster black hole that weighs a whopping 4.5 billion solar masses, or more than 1,000 times bigger than the black hole in our galaxy. When that happens, the black holes in both galaxies also likely will merge. Both galaxies are 50 million light-years away.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington.
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Kepler 186F: un nom nimbé de mystères

Kepler 186F: un nom nimbé de mystères | Tout est relatant | Scoop.it

L'exoplanète Kepler 186F est à peine 10% plus grande que la Terre. Elle est située dans la zone habitable de son étoile, comme la Terre l'est avec le Soleil. Elle fascine les scientifiques, notamment à cause de sa ressemblance avec notre planète bleue. Il s'agit de la première exoplanète qui pourrait porter de la vie.

Qu’est-ce qu'une exoplanète?

Il s’agit d'une planète extérieure au système solaire. L'immense majorité des planètes de notre galaxie, et au-delà, sont des exoplanètes. Parmi celles-ci, beaucoup sont vagabondes, elles ne tournent autour d'aucune étoile. Mais dans leurs recherches, les scientifiques se concentrent surtout sur celles qui sont dans un système stellaire.

Ainsi, le système stellaire dans lequel se trouve Kepler 186F est à 490 années-lumière de chez nous, c’est-à-dire à 490 fois 9 460 milliards de kilomètres de distance par rapport à notre Soleil. On comprend donc aisément que les planètes qui sont dans un système sont plus faciles à trouver, mais surtout - et c'est ce qui intéresse les astronomes - les planètes qui ont une étoile ont aussi plus de chance de ressembler à la nôtre.

Qu'est-ce qui fait de la découverte de Kepler une première?

Kepler 186F est la première exoplanète qui remplit tous les critères extérieurs de ressemblance à la Terre : petite taille, donc possiblement planète rocheuse, et dans la zone habitable de son étoile, c'est-à-dire cette zone ni trop chaude, ni trop froide qui permettrait la présence d'eau liquide.

Toutes les autres planètes découvertes jusqu'à maintenant, près de 1 800 depuis 1994, étaient soit de grosses planètes dont il était difficile de déterminer la nature - gazeuse ou rocheuse -, soit des petites planètes trop lointaines ou trop proches de leur soleil. L’enjeu, c’est la possibilité qu’une planète porte de l’eau, donc de la vie.

Quel est l'objectif poursuivi par les scientifiques?

Trouver des preuves de vie dans l’Espace. Voilà ce qui anime, aujourd'hui plus que jamais, la communauté de l'astrophysique. Les scientifiques cherchent à voir si les conditions de naissance de la vie sont rassemblées. Ils cherchent donc des planètes où les températures coïncident avec la présence d'eau liquide. Ils s’intéressent aussi à la composition de l'atmosphère et se demandent notamment s'il y a de l'ozone dans l’atmosphère. On sait que la vie sur Terre est née grâce à l'eau, à l'ozone et au carbone.

Malheureusement, pour l'instant, nos connaissances à propos de Kepler 186F proviennent surtout de calculs et d’extrapolations mathématiques.

Que leur manque-t-il?

Il manque aux scientifiques des satellites suffisamment puissants pour connaitre la masse exacte de Kepler 186F, ce qui permettrait de savoir de manière certaine si la planète est rocheuse. Ils pourraient aussi déterminer la nature de l'atmosphère, et mener diverses analyses à distance pour mieux connaître la planète. Tous les instruments pour faire ces mesures existent déjà, pas le satellite.

Kepler, le satellite qui a découvert cette exoplanète, a pour mission de détecter les planètes, pas de les analyser. Les projets de missions qui pourraient mener à une analyse en profondeur de la jumelle de la Terre sont dans les cartons, d'après les scientifiques de l'Oservatoire d'astrophysique de Bordeaux, mais il leur faudrait une dizaine d'années pour voir le jour. Cette découverte pourrait conditionner de nouvelles missions, plus ciblées, pour vraiment élucider les mystères de Kepler 186F.

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NASA Spots Square-Shaped 'Hole' in the Sun (Video)

NASA Spots Square-Shaped 'Hole' in the Sun (Video) | Tout est relatant | Scoop.it

A NASA spacecraft has made a surprising find on the surface of the sun: a square-shaped "hole" in the star's outer atmosphere.

The dark square on the sun, known as a "coronal hole," is an area where the solar wind is streaming out of the sun at superfast speeds. NASA captured a video of the sun's square-shaped coronal hole between Monday and Wednesday (May 5-7) using the powerful Solar Dynamics Observatory (SDO).

The coronal hole appears dark in the NASA view because there is less material emitting light in the ultraviolet range of the spectrum used to make the video, according to a NASA video description. [Biggest Solar Storms of 2014 (Photos)]

 

"Inside the coronal hole you can see bright loops where the hot plasma outlines little pieces of the solar magnetic field sticking above the surface," SDO officials wrote in the video description. "Because it is positioned so far south on the sun, there is less chance that the solar wind stream will impact us here on Earth."

NASA's sun-watching Solar Dynamics Observatory is just one of a fleet of spacecraft keeping a close watch on the weather on Earth's parent star. In 2013, the sun experienced its peak activity of its 11-year solar weather cycle.

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Un exosquelette pour commander à distance les robots

Un exosquelette pour commander à distance les robots | Tout est relatant | Scoop.it

Le laboratoire de robotique téléopérée de l’Agence Spatiale Européenne (ESA) a mis au point un exosquelette pour contrôler à distance un robot qui à son tour réalise des opérations dans l’espace. Une démonstration de ce système vient d’être fait cette semaine.

Ce jeudi 8 mai, à la conférence TEDx RocketMinds qui s’est tenue dans le centre des opérations de l’ESA à Darmstadt, en Allemagne, cette équipe de chercheurs en robotique a fait la démonstration d’un exosquelette en liaison directe avec un robot situé à plus de 400 kilomètres de là, à Noordwijk aux Pays-Bas.

L’exosquelette, pesant seulement 10 kilos, est alimenté par batteries et envoie des commandes via un réseau cellulaire. Il peut être déployé rapidement et fonctionne tant que le robot est dans une zone couverture par un réseau télécom. L’opérateur revêt l’exosquelette et effectue les gestes qu’il veut faire faire au robot à distance.

Le robot va reproduire ensuite les mouvements du bras et de la main effectués par l’opérateur. L’intérêt de ce système se situe dans sa capacité à transmettre par retour de force les obstacles que le robot rencontre. Ainsi, la personne portant l’exosquelette se rend compte des contraintes du robot et peut le contrôler plus précisément.

Bien que l’équipe l’ait développé initialement pour des missions dans l’espace, cette solution peut également être très utile pour des applications terrestres très concrètes. Comme par exemple une situation d’urgence après une catastrophe naturelle. On peut tout à fait imaginer qu’après un tremblement de terre, un robot soit envoyé sur place pour extraire les corps. A distance, à quelques mètres ou à plusieurs centaines de kilomètres, l’opérateur se servira de l’exosquelette pour faire déplacer au robot les rochers et tirer la personne des décombres d’un immeuble effondré.

Envoyer des robots dans des zones sinistrées est une quête de longue haleine pour le secteur du secourisme. Avec ce dispositif, fonctionnel même en cas de coupure des réseaux électriques et de télécommunications, l’ESA a sans doute une première réponse.

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Nearest bright 'hypervelocity star' found

Nearest bright 'hypervelocity star' found | Tout est relatant | Scoop.it

A University of Utah-led team discovered a “hypervelocity star” that is the closest, second-brightest and among the largest of 20 found so far. Speeding at more than 1 million mph, the star may provide clues about the supermassive black hole at the center of our Milky Way and the halo of mysterious “dark matter” surrounding the galaxy, astronomers say.

“The hypervelocity star tells us a lot about our galaxy – especially its center and the dark matter halo,” says Zheng Zheng, an assistant professor of physics and astronomy and lead author of the study published recently in Astrophysical Journal Letters by a team of U.S. and Chinese astronomers.

“We can’t see the dark matter halo, but its gravity acts on the star,” Zheng says. “We gain insight from the star’s trajectory and velocity, which are affected by gravity from different parts of our galaxy.”

In the past decade, astronomers have found about 20 of these odd stars. Hypervelocity stars appear to be remaining pairs of binary stars that once orbited each other and got too close to the supermassive black hole at the galaxy’s center. Intense gravity from the black hole – which has the mass of 4 million stars like our sun – captures one star so it orbits the hole closely, and slingshots the other on a trajectory headed beyond the galaxy.

Zheng and his colleagues discovered the new hypervelocity star while conducting other research into stars with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, or LAMOST, located at the Xinglong Observing Station of the National Astronomical Observatories of China, about 110 miles northeast of Beijing.

LAMOST boasts a 13.1-foot-wide aperture and houses 4,000 optical fibers, which capture “spectra” or light-wavelength readings from as many as 4,000 stars at once. A star’s spectrum reveals information about its velocity, temperature, luminosity and size.

LAMOST’s main purpose is to study the distribution of stars in the Milky Way, and thus the galaxy’s structure. The new hypervelocity star – named LAMOST-HVS1 – stood out because its speed is almost three times the usual star’s 500,000-mph pace through space: 1.4 million mph relative to our solar system. Its speed is about 1.1 million mph relative to the speed of the center of the Milky Way.

Despite being the closest hypervelocity star, it nonetheless is 249 quadrillion miles from Earth. (In U.S. usage, a quadrillion is 1,000,000,000,000,000 miles or 10 to the 15th power, or 1 million billion).

“If you’re looking at a herd of cows, and one starts going 60 mph, that’s telling you something important,” says Ben Bromley, a University of Utah physics and astronomy professor who was not involved with Zheng’s study. “You may not know at first what that is. But for hypervelocity stars, one of their mysteries is where they come from – and the massive black hole in our galaxy is implicated.”

The Down-Low on a Fast and Loose Star

A cluster of known hypervelocity stars, including the new one, is located above the disk of our Milky Way galaxy, and their distribution in the sky suggests they originated near the galaxy’s center, Zheng says.

The diameter of the visible part of our spiral-shaped galaxy is at least 100,000 light years, or 588 quadrillion miles. Zheng says that when the halo of dark matter is added, the estimated diameter is roughly 1 million light years, or 5,880 quadrillion miles.

Scientists know dark matter halos surround galaxies because the way their gravity affects the motion of a galaxy’s visible stars and gas clouds. Researchers say only about 5 percent of the universe is made of visible matter, 27 percent is invisible and yet-unidentified dark matter and 68 percent is even more mysterious dark energy, responsible for accelerating the expansion of the universe. By traveling through the dark matter halo, the new hypervelocity star’s speed and trajectory can reveal something about the mysterious halo.

Our solar system is roughly 26,000 light years or 153 quadrillion miles from the center of the galaxy – more than halfway out from the center of the visible disk.

By comparison, the new hypervelocity star is about 62,000 light years or 364 quadrillion miles from the galactic center, beyond as well as above the galaxy’s visible disk. It is about 42,400 light years from Earth, or about 249 quadrillion miles away.

As far as that is – the star has a magnitude of about 13, or 630 times fainter than stars that barely can be seen with the naked eye – it nevertheless “is the nearest, second-brightest, and one of the three most massive hypervelocity stars discovered so far,” Zheng says.

It is nine times more massive than our sun, which makes it very similar to another hypervelocity star known as HE 0437-5439, discovered in 2005, and both are smaller than HD 271791, which was discovered in 2008 and is 11 times more massive than the sun. As seen from Earth, only HD 271791 is brighter than LAMOST-HVS1, Zheng says.

The newly discovered hypervelocity star also outshines our own sun: It is four times hotter and about 3,400 times brighter (if viewed from the same distance). But compared with our 4.6-billion-year-old sun, the newly discovered LAMOST–HVS1 is a youngster born only 32 million years ago, based on its speed and position, Zheng says.

Is there any chance that the supermassive black hole might hurl a hypervelocity star in Earth’s direction one day? Not really, Zheng says. First, astrophysicists estimate only one hypervelocity star is launched every 100,000 years. Second, possible trajectories of stars near the supermassive black hole don’t forebode any danger, should any of them become a hypervelocity star in the future.
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Gaia Flight Model Mass Properties Testing

Gaia Flight Model Mass Properties Testing | Tout est relatant | Scoop.it
TThe Gaia Spacecraft Flight Model has successfully completed its mass properties test campaign.

The mass properties of a spacecraft (total mass, centre of gravity [CoG] and moment of inertia [MoI] about all three axes) are among the characteristics calculated during the design process. Since the correct control and guidance of the spacecraft depend on an accurate knowledge of these values, they are subsequently measured as part of the test campaign. The integrated Gaia Flight Model (FM) spacecraft has completed its mass properties test campaign at the premises of Intespace in Toulouse, France.

Measurement of the mass ensures that the completed spacecraft has a total mass that is within the design tolerances. This value is important for the launch, spin-up and injection into the transfer orbit to reach the operational orbit at the second Lagrange point of the Sun-Earth system (L2). A weighing scale was used to determine the spacecraft's mass with an accuracy of 0.4 kg.

Top left: Gaia spacecraft on the weighing scale for total mass measurement. Top right, lower left and lower right: Gaia spacecraft being lifted from the weighing scale.
Credit: ESA/Stefan Corvaja

Determining the location of the CoG of the spacecraft confirms that it is located within the design tolerances. Knowledge of the CoG position is important because it dictates how the spacecraft will behave when the sets of chemical and micropropulsion thrusters are fired asymmetrically, to rotate the spacecraft, rather than symmetrically, to change velocity. The CoG position was determined to approximately 2 mm for the X-axis, and approximately 0.35 mm for the Y and Z axes.

Measuring the MoI about each of the spacecraft's axes and deriving the Products of Inertia (PoI) is performed so that its 'resistance' to rotation about any axis is available for refining the algorithms that the Attitude and Orbit Control System (AOCS) uses to control the spacecraft's orientation by firing the chemical or micropropulsion thrusters. The MoI about the X-axis was determined with an accuracy of  better than 10 kg m⊃2;, and better than 30 kg m⊃2; for the Y and Z axes.

The Gaia spacecraft being lifted from its ground handling trolley, which was used to rotate the spacecraft through 90° ready for testing in a horizontal position. Credit: ESA/Stefan Corvaja

The Gaia spacecraft being installed on the mass properties testing equipment in a horizontal position. Credit: ESA/Stefan Corvaja

ABOUT GAIA

Gaia will create a three-dimensional map of the Milky Way, in the process revealing information about its composition, formation and evolution. The mission will perform positional measurements for about one billion stars in our Galaxy and Local Group with unprecedented precision, together with radial velocity measurements for the brightest 150 million objects. Gaia is scheduled to launch in 2013 for a nominal five-year mission, with a possible one-year extension.

The spacecraft will operate in a Lissajous orbit around the second Lagrange point of the Sun-Earth system (L2). This location in space offers a very stable thermal environment, very high observing efficiency (since the Sun, Earth and Moon are all behind the instrument FoV) and a low radiation environment. Uninterrupted mapping of the sky will take place during the operational mission phase.

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Problème d'antenne sur l'ISS: 2 cosmonautes sortent dans l'espace

Problème d'antenne sur l'ISS: 2 cosmonautes sortent dans l'espace | Tout est relatant | Scoop.it

Deux membres de l'équipage de la Station spatiale internationale (ISS) sont sortis dans l'espace jeudi pour inspecter des antennes de la station, a indiqué le centre russe de contrôle des vols spatiaux (Tsoup).
Les cosmonautes russes Alexandre Missourkine et Fiodor Iourtchikhine ont quitté la station à 11H34 GMT et doivent passer près de cinq heures et demi hors de l'ISS, a précisé le Tsoup, sur son site officiel. 

 


"L'astronaute américain Christopher Cassidy a aperçu lundi à travers un hublot que le couvercle de l'une des six antennes installées sur le module russe Zvezda se détachait et s'envolait", a indiqué une source au sein du secteur spatial, citée par l'agence Interfax.
Le Tsoup a alors ordonné aux cosmonautes d'inspecter les autres antennes et de serrer les vis de leurs couvercles qui risquent aussi de se détacher, selon Interfax.
Les cosmonautes doivent aussi faire des prélèvements sur la surface de la station pour vérifier que des éléments chimiques et des micro-organismes capables d'endommager le corps de l'ISS ne s'y trouvent pas.

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EVA 23: exploring the frontier

EVA 23: exploring the frontier | Tout est relatant | Scoop.it

My eyes are closed as I listen to Chris counting down the atmospheric pressure inside the airlock – it’s close to zero now. But I’m not tired – quite the reverse! I feel fully charged, as if electricity and not blood were running through my veins. I just want to make sure I experience and remember everything. I’m mentally preparing myself to open the door because I will be the first to exit the Station this time round. Maybe it’s just as well that it’s night time: at least there won’t be anything to distract me.

When I read 0.5 psi, it’s time to turn the handle and pull up the hatch. It is pitch black outside, not the colour black but rather a complete absence of light. I drink in the sight as I lean out to attach our safety cables. I feel completely at ease as I twist my body to let Chris go by. In a matter of seconds, we finish checking each other and we separate. Even though we are both heading to more or less the same part of the International Space Station, our routes are completely different, set out by the choreography we have studied meticulously. My route is direct, towards the back of the Station, while Chris has to go towards the front first in order to wind his cable around Z1, the central truss structure above Node 1. At that moment, none of us in orbit or on Earth could have imagined just how much this decision would influence the events of the day.

I pay careful attention to every move as I make my way towards the protective bag that we left outside the week before. I don’t want to make the mistake of feeling so much at ease as to be relaxed. Inside the bag I find the cables that form part of what will perhaps be my most difficult task of the day. I have to connect them to the Station’s external sockets while at the same time securing them to the surface of the station with small metal wires. Both operations involve me using my fingers a lot, and I know from experience that this will be really tiring because of the pressurised gloves.

NASA astronaut Chris Cassidy. Credits NASA

Chris partially connected the first cable last week, so I get hold of the part that is still unattached and I guide it carefully towards the socket. After a little initial difficulty, I inform Houston that I have completed the task and I’m ready for the second cable. After getting hold of the next cable, I move into what I think is the most difficult position to work from on the whole Station: I’m literally wedged between three different modules, with my visor and my PLSS (my ‘backpack’) just a few centimetres from the external walls of Node 3, Node 1 and the Lab. Very patiently, with considerable effort I manage to fasten one end of the second cable to the socket. Then, moving blindly backwards, I free myself from the awkward position I’d had to work in. On the ground, Shane tells me that I’m almost 40 minutes ahead of schedule, and Chris is also running ahead on his tasks.

At this exact moment, just as I’m thinking about how to uncoil the cable neatly (it is moving around like a thing possessed in the weightlessness), I ‘feel’ that something is wrong. The unexpected sensation of water at the back of my neck surprises me – and I’m in a place where I’d rather not be surprised. I move my head from side to side, confirming my first impression, and with superhuman effort I force myself to inform Houston of what I can feel, knowing that it could signal the end of this EVA. On the ground, Shane confirms they have received my message and he asks me to await instructions. Chris, who has just finished, is still nearby and he moves towards me to see if he can see anything and identify the source of the water in my helmet.

At first, we’re both convinced that it must be drinking water from my flask that has leaked out through the straw, or else it’s sweat. But I think the liquid is too cold to be sweat, and more importantly, I can feel it increasing. I can’t see any liquid coming out of the drinking water valve either. When I inform Chris and Shane of this, we immediately receive the order to ‘terminate’ the sortie. The other possibility, to ‘abort’, is used for more serious problems. I’m instructed to go back to the airlock. Together we decide that Chris should secure all the elements that are outside before he retraces his steps to the airlock, i.e. he will first move to the front of the Station. And so we separate.

Luca "jammed"between three ISS modules.

As I move back along my route towards the airlock, I become more and more certain that the water is increasing. I feel it covering the sponge on my earphones and I wonder whether I’ll lose audio contact. The water has also almost completely covered the front of my visor, sticking to it and obscuring my vision. I realise that to get over one of the antennae on my route I will have to move my body into a vertical position, also in order for my safety cable to rewind normally. At that moment, as I turn ‘upside-down’, two things happen: the Sun sets, and my ability to see – already compromised by the water – completely vanishes, making my eyes useless; but worse than that, the water covers my nose – a really awful sensation that I make worse by my vain attempts to move the water by shaking my head. By now, the upper part of the helmet is full of water and I can’t even be sure that the next time I breathe I will fill my lungs with air and not liquid. To make matters worse, I realise that I can’t even understand which direction I should head in to get back to the airlock. I can’t see more than a few centimetres in front of me, not even enough to make out the handles we use to move around the Station.

I try to contact Chris and Shane: I listen as they talk to each other, but their voices are very faint now: I can hardly hear them and they can’t hear me. I’m alone. I frantically think of a plan. It’s vital that I get inside as quickly as possible. I know that if I stay where I am, Chris will come and get me, but how much time do I have? It’s impossible to know. Then I remember my safety cable. Its cable recoil mechanism has a force of around 3lb that will ‘pull’ me towards the left. It’s not much, but it’s the best idea I have: to follow the cable to the airlock. I force myself to stay calm and, patiently locating the handles by touch, I start to move, all the while thinking about how to eliminate the water if it were to reach my mouth. The only idea I can think of is to open the safety valve by my left ear: if I create controlled depressurisation, I should manage to let out some of the water, at least until it freezes through sublimation, which would stop the flow. But making a ‘hole’ in my spacesuit really would be a last resort.

Mission Control, Houston.
Credits NASA

I move for what seems like an eternity (but I know it’s just a few minutes). Finally, with a huge sense of relief, I peer through the curtain of water before my eyes and make out the thermal cover of the airlock: just a little further, and I’ll be safe. One of the last instructions I received was to go back inside immediately, without waiting for Chris. According to protocol, I should have entered the airlock last, because I was first to leave. But neither Chris nor I have any problem in changing the order in which we re-enter. Moving with my eyes closed, I manage to get inside and position myself to wait for Chris’ return. I sense movement behind me; Chris enters the airlock and judging from the vibrations, I know that he’s closing the hatch. At that moment, communication passes to Karen and for some reason, I’m able to hear her fairly well. But I realise that she can’t hear me because she repeats my instructions even though I’ve already replied. I follow Karen’s instructions as best I can, but when repressurization begins I lose all audio. The water is now inside my ears and I’m completely cut off.

I try to move as little as possible to avoid moving the water inside my helmet. I keep giving information on my health, saying that I’m ok and that repressurization can continue. Now that we are repressurizing, I know that if the water does overwhelm me I can always open the helmet. I’ll probably lose consciousness, but in any case that would be better than drowning inside the helmet. At one point, Chris squeezes my glove with his and I give him the universal ‘ok’ sign with mine. The last time he heard me speak was before entering the airlock!

The minutes of repressurization crawl by and finally, with an unexpected wave of relief, I see the internal door open and the whole team assembled there ready to help. They pull me out and as quickly as possible, Karen unfastens my helmet and carefully lifts it over my head. Fyodor and Pavel immediately pass me a towel and I thank them without hearing their words because my ears and nose will still be full of water for a few minutes more.

Space is a harsh, inhospitable frontier and we are explorers, not colonisers. The skills of our engineers and the technology surrounding us make things appear simple when they are not, and perhaps we forget this sometimes.

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Air Force Space Command discontinues space surveillance system

Air Force Space Command discontinues space surveillance system | Tout est relatant | Scoop.it
PETERSON AIR FORCE BASE, Colo. -- Due to resource constraints caused by sequestration, Air Force Space Command has directed the 21st Space Wing to prepare to discontinue operations at the Air Force Space Surveillance System by Oct. 1. Final decisions on all Fiscal Year 2014 budget issues will be made over the next few weeks. By discontinuing operations, the AFSSS would not be maintained in operational status; however, equipment will not be removed until a final disposition determination is made. 

The AFSSS sites are operated under contract and the 21st SW has notified the vendor, Five Rivers Services in Colorado Springs, Colo., that it most likely will not exercise the next contract option beginning Oct. 1. By de-activating the AFSSS by Oct. 1, AFSPC would see a cost savings of approximately $14 million per year, beginning in Fiscal Year 2014. 

AFSPC has devised modified operating modes for the Perimeter Acquisition Radar Characterization System at Cavalier AFS, N.D., and for the space surveillance Radar at Eglin AFB, Fla., which allows the discontinuation of AFSSS operations while still maintaining solid space situational awareness. 

The AFSSS is a series of three transmitters and six receivers along the 33rd parallel stretching across the southern United States. The three transmitter sites are located at Jordan Lake, Ala.; Lake Kickapoo, Texas; and Gila River, Ariz. The six receivers are located at Tattnall, Ga.; Hawkinsville, Ga.; Silver Lake, Miss.; Red River, Ark.; Elephant Butte, N.M.; and San Diego, Calif. The two receiver sites at Tattnall and Silver Lake were deactivated in April of this year.

The AFSSS, which has been operational since 1961, is just one part of AFSPC's global Space Surveillance Network. The system is designed to transmit a "fence" of radar energy vertically into space to detect all objects intersecting that fence. The operational advantage of the AFSSS is its ability to detect objects in an un-cued fashion, rather than tracking objects based on previous information. The disadvantage is the inherent inaccuracy of the data, based on its dated design. The new operating modes at Cavalier and Eglin will provide more accuracy than the AFSSS and still collect un-cued observations.

The AFSSS is typically referred to as the "Space Fence," which has caused confusion with the new Space Fence being developed for the future. "The AFSSS is much less capable than the Space Fence radar planned for Kwajalein Island in the Republic of the Marshall Islands," said General William L. Shelton, Commander, Air Force Space Command. "In fact, it's apples and oranges in trying to compare the two systems." 

Unlike the AFSSS, the new Space Fence will provide very precise positional data on orbiting objects and will be the most accurate radar in the Space Surveillance Network. It will provide enhanced space surveillance capabilities to detect and track orbiting objects such as commercial and military satellites, depleted space boosters and space debris. The new Space Fence will have much greater sensitivity, allowing it to detect, track and measure an object the size of a softball orbiting more than 1,200 miles in space. Because it is also an un-cued tracking system, it will provide evidence of satellite break-ups, collisions, or unexpected maneuvers of satellites. 

"When combined with the new Joint Space Operations Center's high performance computing environment, the new Fence will truly represent a quantum leap forward in space situational awareness for the Nation," General Shelton said. 

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Talking 'robot astronaut' blasts into space

Talking 'robot astronaut' blasts into space | Tout est relatant | Scoop.it
A talking humanoid robot, Kirobo, takes off on board a supply ship bound for the International Space Station from Japan's Tanegashima Space Centre.

The first talking humanoid robot, Kirobo, took off from Japan'sTanegashima Space Centre, Kagoshima Prefecture, early on Sunday morning.

Japanese rocket, H-IIB Transfer Vehicle, took off at 4:46am local time on Sunday (19:46 GMT), heading for the International Space Station with close to five and a half tons (tonnes) of supplies and equipment.

Kirobo was on board Konotori 4, an unmanned space cargo transporter, and is expected to reach the ISS on August 9.

While conventional robots in space have usually been tasked with maintenance or mechanical operations, Kirobo's mission is to be a companion to Japanese astronaut Koichi Wakata on-board the International Space Station.

Kirobo's land-based double robot, the Mirata, stayed on Earth.

 

The name Kirobo derives from the Japanese words "Hope" and "Robot," while Mirata comes from the word "future."

The endeavour is a joint project between advertising company Dentsu, auto giant Toyota and robot creator Tomotaka Takahashi at the University of Tokyo's Research Centre for Advanced Science and Technology.

The system behind the robot's conversational functions and intelligence was designed by auto giant Toyota.

The robonaut duo is capable of recognising human voice and speech, has preprogrammed responses and actions to questions while it can also create verbal responses based on its past conversations.

Mr Takahashi, who heads his own robotics company, designed the Kirobo/Mirata hardware and their physical movements.

The biggest challenge, he said is making the robot compatible with space. It took more than nine months and dozens of tests to ensure its reliability.

Among the tests was taking a parabolic flight test to see if the Kirobo can move and talk in a low-gravity environment.

The experiment was done on a small jet plane which can artificially reconstruct a low-gravity state for brief periods of time.

Another experiment has tested the compatibility of the robot's power system with that of the International Space Station.

The Kirobo and Mirata stand 13 inches tall, 7 inches wide, weigh just under 2.2 pounds, and for now, speak only Japanese.

Kirobo will await Mr Wakata's arrival at the International Space Station which is due around November.

Aboard the ISS, the two will engage in communication tests to see whether and how far the Kirobo can autonomously hold conversations with Wakata, as well as how its remote control functions from Earth.

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China’s Long March 2C launches Shijian 11-05 | NASASpaceFlight.com

China’s Long March 2C launches Shijian 11-05 | NASASpaceFlight.com | Tout est relatant | Scoop.it

After the successful completion of the Shenzhou-10 mission to the Tangong-1 orbital module, China embarked for the second half of 2013 with the successful launch of another mysterious satellite on the Shijian-11 series. The launch of Shijian 11-05 took place at 09:27UTC on Monday using a Long March 2C launch vehicle from the 603 launch pad of the LC43 launch complex from the Jiuquan Satellite Launch Center.

Chinese Launch:

This is the fifth satellite of the series, following the loss of the fourth satellite after the failure of the Long March 2C on August 18, 2011.

According to the Chinese media, this mission involved an “experimental satellite” developed by the DongFangHong Satellite Company of the China Aerospace Science and Technology Corp.

As with the previous Shijian-11 satellites, the true mission of Shijian 11-05 was not revealed by the Chinese authorities. However, some observers noted that the Shijian-11 series could be related with a constellation of operational early warning satellites.

‘Shijian’ means ‘Practice’ and this series of satellites have been used with a variety of configurations and missions for scientific research and technological experiments.

The first ShiJian-11 (36088 2009-061A) was launched at 0245:04UTC on November 12, 2009 by the Chang Zheng 2C (Y21) from the Jiuquan Satellite Launch Center. The second satellite on the series, ShiJian 11-03 (37730 2011-030A) was launched at 0428:03.993UTC on July 6, 2011, by the CZChang Zheng-2C (Y25), also from Jiuquan.

Shijian 11-02 (37765 2011-039A) was the third satellite in the series and was launched at 0742:03.570UTC on July 29, 2011 from Jiuquan by the Chang Zheng-2C (Y24) launch vehicle.

All satellites operate in typical 705 by 690 km, 98.1 degrees orbits.

 

The Chang Zheng 2C (Long March 2C) is a Low Earth Orbit (LEO) launch vehicle derived from DF-5 ICBM. It can be launched from either the Jiuquan Satellite Launch Center or the Taiyuan Satellite Launch Center.

The rocket is a two stage hypergolic launch vehicle with a total length of 35.15 meters, a diameter of 3.35 meters and a total mass of 192,000 kg. The first stage is equipped with four YF-20A engines. Is has a length of 20.52 meters and a burn time of 122 seconds.

The second stage is equipped with one YF-22A engine, and has a length of 7.50 meters with a burn time of 130 seconds.

This launch was the 178th Chinese orbital launch, the 178th launch of the Chang Zheng launch vehicle family. It was also the 59th orbital launch from the Jiuquan Satellite launch Center and the fourth orbital launch from China this year.

The Jiuquan Satellite Launch Center, also known as the Shuang Cheng Tze launch center, was the first Chinese satellite launch center.

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Following Russia’s GLONASS set back, US and European GPS advance

Following Russia’s GLONASS set back, US and European GPS advance | Tout est relatant | Scoop.it

While investigators continue to search through the debris of the failed launch of three Russian GLONASS navigation satellites, the United States and Europe have announced progress with their fleet of upcoming GPS spacecraft. The first Galileo Full Operational Capability (FOC) satellite is now undergoing testing in Holland, while Lockheed Martin’s GPS III program passed a major development milestone.


GPS was created by the US Department of Defense (DoD) and became fully operational in 1994. Serving both the military and the public alike, the use of GPS has rocketed in recent years, not least via the use of navigation aids in personal mobile devices.

The Americans lead the way with their GPS satellite fleet, with the most recent launch coming via the successful deployment of the fourth Block IIF GPS satellite – GPS IIF-4 – the sixty-fourth GPS satellite overall.

The next generation of navigation satellites – known as GPS III – is on track for a 2014 launch, with Lockheed Martin currently under contract for production of the first four GPS III satellites (SV 1-4), while they have also received advanced procurement funding for long-lead components for the fifth, sixth, seventh and eighth satellites (SV 5-8).

In preparation for the new fleet, the GPS III Non-Flight Satellite Testbed (GNST) successfully completed a series of high-fidelity pathfinding events, validating the process and facility for vehicle integration checkout, as well as signals interference testing.

The GNST is a full-sized GPS III satellite prototype, used to identify and resolve development issues prior to integration and test of the first GPS III space vehicle (SV 1).

During this latest milestone, the GNST successfully completed thermal vacuum (T-Vac) chamber trail blazing, demonstrating facility, mechanical and electrical ground equipment integration, and ran a series of vehicle integration test procedures.

The GNST also completed Passive Intermodulation (PIM) and Electromagnetic Compatibility (EMC) testing, which assures that multiple high-powered signals generated from the satellite’s navigation downlink transmissions, or transmitted from the hosted nuclear detection system payload on the satellite, do not interfere with each other or themselves.

“As the GNST serves as a pathfinder for the GPS III program, its successful completion of this testing validates that development risks have been retired and our engineering and technology is sound for the flight vehicles being built,” explained Keoki Jackson, vice president for Lockheed Martin’s Navigation Systems mission area.


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