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Sonntag, 19. Mai 2013 - 14:25 Uhr

Raumfahrt - DLR-Roboter TORO

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Ein Roboter wird komplett: Arme und Hände für Gehmaschine "TORO"

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Angefangen hat es im Sommer 2009 mit zwei Beinen und einer darauf montierten Kamera. Allerdings war das äußerlich noch weit entfernt von einem Roboter nach menschlichem Vorbild. Nach und nach aber wurde die Gehmaschine "TORO" des Deutschen Zentrums für Luft- und Raumfahrt (DLR) menschenähnlicher: Ein Oberkörper, ein Kopf mit Kameraaugen und Oberarme folgten. Mit Unterarmen und Händen ist "TORO", der mit Sensoren und nachgiebigen Gelenken feinfühlig auf seine Umgebung reagieren kann, jetzt komplett. Was für den Menschen einfach ist, wird TORO von nun an in kleinen Schritten lernen müssen: Treppensteigen oder Türöffnen beispielsweise. "Mit dem vollständigen Roboterkörper können wir jetzt die Abläufe testen, bei denen der Roboter vorausschauend und fließend Bewegungsabläufe des Menschen durchführt", erklärt Projektleiter Dr. Christian Ott.

Gehen mit Gefühl

Eines kann "TORO" als Gehmaschine natürlich bereits gut: Gehen. Gleichmäßig setzt der Roboter einen Fuß nach dem anderen auf und bewegt sich in kleinen Schritten vorwärts. Auch wenn die Geschwindigkeit nicht groß ist - bei jedem Schritt nimmt "TORO" über Sensoren in den Füßen wahr, welche Kräfte beim Auftreten wirken. Drehmomentsensoren in den Gelenken sorgen dafür, dass der Roboter flexibel auf seine Umwelt reagiert. Steht die Gehmaschine, balanciert sie Stöße gegen die Beine nachgiebig aus. Auch auf einem Kippbrett schafft "TORO" das bereits. "Wir arbeiten daran, dass das auch im Gehen besser funktioniert", sagt Ott. Dabei sind die Füße von "TORO" auffällig klein. Eine schwierige Hürde, die sich die Wissenschaftler selbst gewählt haben. "Wir wollten es uns mit der geringen Standfläche zum einen schwerer machen, zum anderen kann der Roboter so leichter über Hindernisse steigen." Mit der Berücksichtigung von Oberkörper und Armen kommt nun eine weitere Herausforderung hinzu.

Experimentierfeld auf zwei Beinen

Die Gehmaschine ist für die Wissenschaftler kein einfacher Roboter, der bestimmte Aufgaben lernen und übernehmen soll, sondern ein Experimentierfeld für die gesamte notwendige Technik. Während andere Roboter sich vor allem in bekannter Umgebung geplant bewegen sollen, soll "TORO" andere Talente entwickeln: Er soll sich vor allem selbstständig, flexibel und sicher in einer neuen, unbekannten Umgebung bewähren. Dabei greifen die Wissenschaftler des DLR-Zentrums für Robotik und Mechatronik auf bereits erworbenes Wissen zurück: Arme und Beine von "TORO" basieren auf den Leichtbaurobotern des DLR, die auch bereits schon für Arbeitsschritte in der Autoproduktion eingesetzt werden. Auch diese sind mit Sensoren ausgestattet und reagieren bei Störungen von außen nachgiebig. Für die Beine der Gehmaschine wählten die Wissenschaftler besonders starke Motoren, für die Arme durften es etwas schwächere Motoren sein - für das Aussehen von "TORO" bedeutet dies kräftige Beine und dünnere Arme.

Intuitiv wie ein Mensch

Mit den Armen und Händen wird "TORO" die nächste Entwicklungsstufe angehen, bei dem die Interaktion mit der Umgebung noch größer ist.  "Wenn ein Mensch zum Beispiel eine schwere Tür öffnet, macht er das in einem dynamischen Vorgang", betont Projektleiter Ott. "Er weiß unbewusst, welche Bewegungen er durchführen muss - das soll unser Roboter auch können." Wann übt man beim Öffnen der Tür Druck aus, wann gibt man nach, wie verlagert man dabei den Oberkörper? Für Menschen ist dieses Wissen intuitiv, "TORO" soll seinem Vorbild darin folgen. In seinem Oberkörper meldet zum Beispiel ein Neigungssensor Beschleunigung und Drehrate. "Ein anderes Ziel ist das  Treppensteigen: TORO soll lernen, wie man sich dabei wie ein Mensch am Treppengeländer hochzieht." Die ersten Hände für die Gehmaschine sind dabei einfach gehalten: Sie können greifen, aber nicht so geschickt agieren wie beispielsweise die feinfühligen Hände von DLR-Roboter Justin, der selbst Behälter öffnen und Gläser greifen kann. "Die Arbeit mit TORO ist ein kontinuierlicher Prozess", sagt DLR-Wissenschaftler Christian Ott. "Dabei soll aus der Gehmaschine kein optimaler Laufroboter werden - sondern ein ständiger Lieferant für neues Wissen."

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Quelle: DLR


3199 Views

Samstag, 18. Mai 2013 - 22:30 Uhr

UFO-Forschung - UFO-Sichtungen in China waren Raketentests

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Seltsame fliegenden Objekte, die am Montag in China gesichtet wurden, waren Starts chinesischer Raketen.

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Die seltsamen fliegenden Objekte, die am Montag im Himmel über einer Reihe von Gebieten Südchinas zu beobachten waren, haben nun eine Erklärung bekommen: Es habe sich um Starts chinesischer Raketen gehandelt, die zu Forschungszwecken vorgenommen worden seien.

Die Beschreibungen dieser Starts, die von den offiziellen chinesischen Massenmedien und von US-Beobachtern gegeben worden sind, unterscheiden sich nur unwesentlich voneinander, stellt Wasilij Kaschin, Experte des Zentrums für Analyse von Strategien und Technologien, fest.

Die Nachrichtenagentur Xinhua hat eine Erklärung der Akademie der Wissenschaften der VR China verbreitet, wonach meteorologische Raketen gestartet worden seien. Das ist ein gut bekanntes Instrument für wissenschaftliche Forschungen, das seit langem in verschiedenen Ländern Anwendung findet. Relativ preiswerte und einfache ballistische Raketen, die nicht leistungsstark genug sind, um eine erdnahe Umlaufbahn zu erreichen, die jedoch imstande sind, zu den oberen Atmosphärenschichten aufzusteigen und sogar in das Weltall vorzudringen, tragen wissenschaftliche Geräte an Bord. Sie können für die Erforschung der Atmosphäre und Raumstrahlungen sowie zu anderen Zwecken genutzt werden.

China erzeugt und startet regelmäßig meteorologische Raketen, von denen die Rakete T-7 die erste gewesen ist (ihr erster Flug ist 1965 erfolgt). Der im Bau befindliche wichtigste chinesische Kosmodrom Wenchang auf der Insel Hainan hat seine Geschichte als Stützpunkt für die Starts von meteorologischen Raketen in den 1980er Jahren begonnen.

Laut chinesischen Angaben ist am 13, Mai eine neue Rakete, die Gunpeng-7, ein Erzeugnis des Raketen- und Weltraumkonzerns CASIC, gestartet worden. Nach Angaben des astrophysikalischen Zentrums der Harward University (USA) hat die Rakete eine Höhe von 10.000 Kilometer über dem Meeresspiegel erreicht, was den höchsten suborbitalen Flug seit 1976 darstellt. Über die chinesischen meteorologischen Raketen, die zuvor gestartet worden sind, ist bekannt, dass sie eine Höhe von 200 bis 300 Kilometer erreicht haben.

Für den neuen Start sei laut amerikanischen Angaben eine “leistungsstarke Rakete” eingesetzt worden, die potentiell ein Träger von Antisatellitenwaffen sein könnte. Doch nach amerikanischen Einschätzungen lägen keine Anzeichen für militärische Prüfungen vor. Es könnte sich um einen wissenschaftlichen Start handeln, der für die Erforschung der Magnetosphäre der Erde bestimmt sei, wie das von den Chinesen auch erklärt wird.

Sowohl die Chinesen als auch die Amerikaner nennen den Weltraumbahnhof Xichang in der Provinz Sichuan als den Ort des Raketenstarts; dieser Weltraumbahnhof ist auch der Startplatz für die Prüfungen der chinesischen Antisatellitenwaffen gewesen, die in den vergangenen Jahren erfolgt sind. Der Konzern CASIC ist der wichtigste Hersteller von ballistischen Feststoffraketen und zeichnet für das Programm der Entwicklung und Erprobung von Antisatellitenwaffen verantwortlich. Bekannt sind zwei Typen von Trägerraketen, die gegenwärtig gefertigt werden und die CASIC auf dem kommerziellen Markt anbietet: KT-1 (auf der Basis der Mittelstreckenrakete DF-21) und KT-2 (auf der Basis der Interkontinentalrakete DF-31A). Aus amerikanischen Veröffentlichungen ergibt es sich, dass die beiden Systeme auch im Programm für die Entwicklung der chinesischen Antisatellitenwaffen Verwendung fänden.

Somit ist das durchgeführte wissenschaftliche Experiment zwar keine Prüfung des Systems zur Satellitenbekämpfung, doch konnte es wahrscheinlich die Vervollkommnung von Technologien und Systemen bezwecken, die im Rahmen von militärischen Programmen geschaffen worden sind. Es ist durchaus wahrscheinlich, dass die USA das Experiment als einen weiteren Nachweis chinesischer Erfolge bei der Entwicklung von Systemen wahrnehmen werden, die für einen Krieg im Weltraum bestimmt sind.

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Quelle: China Observer

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3317 Views

Samstag, 18. Mai 2013 - 18:00 Uhr

Mars-Chroniken - Opportunity-News

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The pale rock in the upper center of this image, about the size of a human forearm, includes a target called "Esperance," which was inspected by NASA's Mars Exploration Rover Opportunity. Data from the rover's alpha particle X-ray spectrometer (APXS) indicate that Esperance's composition is higher in aluminum and silica, and lower in calcium and iron, than other rocks Opportunity has examined in more than nine years on Mars. Preliminary interpretation points to clay mineral content due to intensive alteration by water. Image Credit: NASA/JPL-Caltech/Cornell/Arizona State Univ.

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PASADENA, Calif. -- NASA's senior Mars rover, Opportunity, is driving to a new study area after a dramatic finish to 20 months on "Cape York" with examination of a rock intensely altered by water.

The fractured rock, called "Esperance," provides evidence about a wet ancient environment possibly favorable for life. The mission's principal investigator, Steve Squyres of Cornell University, Ithaca, N.Y., said, "Esperance was so important, we committed several weeks to getting this one measurement of it, even though we knew the clock was ticking."

The mission's engineers at NASA's Jet Propulsion Laboratory, Pasadena, Calif., had set this week as a deadline for starting a drive toward "Solander Point," where the team plans to keep Opportunity working during its next Martian winter.

"What's so special about Esperance is that there was enough water not only for reactions that produced clay minerals, but also enough to flush out ions set loose by those reactions, so that Opportunity can clearly see the alteration," said Scott McLennan of the State University of New York, Stony Brook, a long-term planner for Opportunity's science team.

This rock's composition is unlike any other Opportunity has investigated during nine years on Mars -- higher in aluminum and silica, lower in calcium and iron.

The next destination, Solander Point, and the area Opportunity is leaving, Cape York, both are segments of the rim of Endeavour Crater, which spans 14 miles (22 kilometers) across. The planned driving route to Solander Point is about 1.4 miles (2.2 kilometers). Cape York has been Opportunity's home since the rover arrived at the western edge of Endeavour in mid-2011 after a two-year trek from a smaller crater.

"Based on our current solar-array dust models, we intend to reach an area of 15 degrees northerly tilt before Opportunity's sixth Martian winter," said JPL's Scott Lever, mission manager. "Solander Point gives us that tilt and may allow us to move around quite a bit for winter science observations."

Northerly tilt increases output from the rover's solar panels during southern-hemisphere winter. Daily sunshine for Opportunity will reach winter minimum in February 2014. The rover needs to be on a favorable slope well before then.

The first drive away from Esperance covered 81.7 feet (24.9 meters) on May 14. Three days earlier, Opportunity finished exposing a patch of the rock's interior with the rock abrasion tool. The team used a camera and spectrometer on the robotic arm to examine Esperance.

The team identified Esperance while exploring a portion of Cape York where the Compact Reconnaissance Spectrometer for Mars (CRISM) on NASA's Mars Reconnaissance Orbiter had detected a clay mineral. Clays typically form in wet environments that are not harshly acidic. For years, Opportunity had been finding evidence for ancient wet environments that were very acidic. The CRISM findings prompted the rover team to investigate the area where clay had been detected from orbit. There, they found an outcrop called "Whitewater Lake," containing a small amount of clay from alteration by exposure to water.

"There appears to have been extensive, but weak, alteration of Whitewater Lake, but intense alteration of Esperance along fractures that provided conduits for fluid flow," Squyres said. "Water that moved through fractures during this rock's history would have provided more favorable conditions for biology than any other wet environment recorded in rocks Opportunity has seen."

NASA's Mars Exploration Rover Project launched Opportunity to Mars on July 7, 2003, about a month after its twin rover, Spirit. Both were sent for three-month prime missions to study the history of wet environments on ancient Mars and continued working in extended missions. Spirit ceased operations in 2010.

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Opportunity Heads Toward Next Destination, 'Solander Point'

This map of a portion of the western rim of Endeavour Crater on Mars shows the area where NASA's Mars Exploration Rover Opportunity worked for 20 months, "Cape York," in relation to the area where the rover team plans for Opportunity to spend its sixth Martian winter, "Solander Point."

The scale bar at lower left is 200 meters (one-eighth of a mile). The inset at upper left indicates the location of the mapped area in relation to the entire Endeavour Crater, which is 14 miles (22 kilometers) in diameter. Both Cape York and Solander Point are raised sections of the crater's western rim.

Opportunity arrived at the edge of Endeavour Crater in August 2011 after a two-year trek from Victoria Crater, where it had spent two years. Observations by NASA's Mars Reconnaissance Orbiter detected traces of clay minerals in a portion of Cape York, and the rover team used that information to guide Opportunity's exploration of the area. Opportunity finished its inspection of targeted rocks on Cape York with examination of "Esperance," indicated on this map. Esperance was found to have a composition suggesting the presence of clay minerals formed by water intensely altering the rock.

Solander Point has a north-facing slope favorable for electrical output by Opportunity's solar panels during the coming southern-hemisphere winter. The minimum-sunshine days of the winter will be in February 2014. The rover team plans to get Opportunity to a northerly tilt well before then. The anticipated drive distance from Esperance to Solander Point is about 1.4 miles (2.2 kilometers). Opportunity began that trek on May 14, 2013.

The base image for this map is from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter.

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This mosaic of four frames shot by the microscopic imager on the robotic arm of NASA's Mars Exploration Rover Opportunity shows a rock target called "Esperance" after some of the rock's surface had been removed by Opportunity's rock abrasion tool, or RAT. Credit: NASA/JPL-Caltech/Cornell/USGS

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Quelle: NASA


Tags: Opportunity-News 

2856 Views

Freitag, 17. Mai 2013 - 15:25 Uhr

Astronomie - Meteoriten-Einschlag auf Mond beobachtet

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May 17, 2013:  For the past 8 years, NASA astronomers have been monitoring the Moon for signs of explosions caused by meteoroids hitting the lunar surface. "Lunar meteor showers" have turned out to be more common than anyone expected, with hundreds of detectable impacts occurring every year.
They've just seen the biggest explosion in the history of the program.
"On March 17, 2013, an object about the size of a small boulder hit the lunar surface in Mare Imbrium," says Bill Cooke of NASA's Meteoroid Environment Office. "It exploded in a flash nearly 10 times as bright as anything we've ever seen before."
Anyone looking at the Moon at the moment of impact could have seen the explosion--no telescope required.  For about one second, the impact site was glowing like a 4th magnitude star.
Ron Suggs, an analyst at the Marshall Space Flight Center, was the first to notice the impact in a digital video recorded by one of the monitoring program's 14-inch telescopes.  "It jumped right out at me, it was so bright," he recalls.
The 40 kg meteoroid measuring 0.3 to 0.4 meters wide hit the Moon traveling 56,000 mph.  The resulting explosion1 packed as much punch as 5 tons of TNT.
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hese false-color frames extracted from the original black and white video show the explosion in progress. At its peak, the flash was as bright as a 4th magnitude star.
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Cooke believes the lunar impact might have been part of a much larger event.
"On the night of March 17, NASA and University of Western Ontario all-sky cameras picked up an unusual number of deep-penetrating meteors right here on Earth," he says. "These fireballs were traveling along nearly identical orbits between Earth and the asteroid belt."
This means Earth and the Moon were pelted by meteoroids at about the same time.
“My working hypothesis is that the two events are related, and that this constitutes a short duration cluster of material encountered by the Earth-Moon system," says Cooke.
One of the goals of the lunar monitoring program is to identify new streams of space debris that pose a potential threat to the Earth-Moon system.  The March 17th event seems to be a good candidate.
Controllers of NASA's Lunar Reconnaissance Orbiter have been notified of the strike.  The crater could be as wide as 20 meters, which would make it an easy target for LRO the next time the spacecraft passes over the impact site.  Comparing the size of the crater to the brightness of the flash would give researchers a valuable "ground truth" measurement to validate lunar impact models.
Unlike Earth, which has an atmosphere to protect it, the Moon is airless and exposed.  "Lunar meteors" crash into the ground with fair frequency. Since the monitoring program began in 2005, NASA’s lunar impact team has detected more than 300 strikes, most orders of magnitude fainter than the March 17th event.  Statistically speaking, more than half of all lunar meteors come from known meteoroid streams such as the Perseids and Leonids.  The rest are sporadic meteors--random bits of comet and asteroid debris of unknown parentage.
U.S. Space Exploration Policy eventually calls for extended astronaut stays on the lunar surface.  Identifying the sources of lunar meteors and measuring their impact rates gives future lunar explorers an idea of what to expect. Is it safe to go on a moonwalk, or not?  The middle of March might be a good time to stay inside.
"We'll be keeping an eye out for signs of a repeat performance next year when the Earth-Moon system passes through the same region of space," says Cooke. “Meanwhile, our analysis of the March 17th event continues.”
Footnote: (1)  The Moon has no oxygen atmosphere, so how can something explode? Lunar meteors don't require oxygen or combustion to make themselves visible.  They hit the ground with so much kinetic energy that even a pebble can make a crater several feet wide.  The flash of light comes not from combustion but rather from the thermal glow of molten rock and hot vapors at the impact site.
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NASA's lunar monitoring program has detected hundreds of meteoroid impacts. The brightest, detected on March 17, 2013, in Mare Imbrium, is marked by the red square.
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Quelle: NASA

Tags: Moon-Impacts Meteorit Mond 

3266 Views

Freitag, 17. Mai 2013 - 13:00 Uhr

Astronomie - Meteorit über Thüringen – Wer hat etwas gesehen?

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16.07.2013

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Am Morgen des 15. Mai 2013 berichten mehrere Personen in Thüringen eine Himmelserscheinung gesehen zu haben.
Thüringen - Am Morgen des 15. Mai 2013, wurden von mehreren Personen eine Leuchterscheinung über den Thüringer Himmel gesehen. Mit großer Wahrscheinlichkeit handelte es sich hierbei um einen größeren Meteoriten, der über Thüringen in die Erdatmosphäre eingedrungen und somit für eine spektakuläre Himmelserscheinung gesorgt hat.
Wer hat den Meteoriten gesehen und kann Angaben zu Ort, Flugrichtung, Helligkeit, Schweif, Geräusche, etc. machen? Wir suchen Augenzeugen die, diesen Meteoriten gesehen haben.
Hierzu haben wir eine Seite eingerichtet um Augenzeugenberichte zusammen zu tragen.
http://www.sterngucker.de/seite/meteorit-ueber-thueringen/
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Sterngucker.de ist das Portal für Beobachtungs- & Erfahrungsberichte von Sternguckern, interessanten astronomischen Artikel sowie technische Daten und detaillierte Spezifikationen über Teleskope, Ferngläser und Zubehöre.
Kontakt:
P35.de
Andy Langzettel
Bahnhofstr. 76
98746 Katzhütte
036781 / 260010
info@sterngucker.de
http://www.sterngucker.de
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Update: 17.05.2013
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Diese Beobachtung kam bei CENAP an:
Hallo, ich habe am Mittwoch 15.5.13 um ca. 9:16Uhr den Tageslicht Meteor
über Thüringen (von Schleiz aus) am Himmel gesehen.
Er fiel aus dem Himmel heraus (nicht am Horizont). Die Sonne stand in meinem
Rücken, so dass ich den angestrahlten Lichtblitz noch deutlicher sehen
konnte. In Richtung West fiel er sehr weiß-blau leuchtend vom Himmel. Ich
sah das flackernde Feuer im Schweif sehr deutlich. Es war sehr
beeindruckend. Als die Sonne im flachen Winkel dann nicht mehr den Meteor
anstrahlte, sah ich einen dunklen Punkt zu Boden rauschen. Es muss ein sehr
großer Brocken gewesen sein. In Molschleben bei Gotha hat ein Ehepaar den
Meteor ebenfalls gesehen. MDR Thüringen berichtete gestern davon.
 LG I.Wetzel
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Ton gibt es hier: http://www.mdr.de/mdr-thueringen/audio547848.html
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Update: Nach neuen Meldungen, konnte der Meteorit auch über Franken (Nördlich von Nürnberg) beobachtet werden.

3025 Views

Freitag, 17. Mai 2013 - 09:00 Uhr

Astronomie - Sind biologische Vorgänge für mysteriöse Wolken der Venus verantwortlich?

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Does Alien Life Thrive in Venus' Mysterious Clouds?

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Personally, I’ve always thought that Venus gets a lot of bad press. Sure, it’s wrapped in clouds so strongly acidic that they dissolved the first few probes we tried to land there, and it has a surface temperature high enough to melt lead — but just above the cloud decks of Venus, you’ll find some of the most “Earth-like” conditions in our entire solar system.
This has prompted some astrobiologists to wonder if, contrary to popular belief, Venus may actually be a home to life of some kind. Perhaps we’ve been looking in the wrong place, and life on Venus is not on its surface but in its clouds.
In fact, roughly 50 to 65 kilometers (30-40 miles) above the surface of Venus, conditions are quite hospitable. Both temperature and pressure are similar to those on Earth. Water vapor and even scarce amounts of free oxygen can be found there. There isn’t much, but it’s there.
Astrobiological studies of Venus are, by nature, highly speculative. The notion sounds audacious but, from what we know of Earth life, it’s certainly not implausible. What’s more, there’s still very much about Earth’s twisted sister that we don’t understand.
We know that there are bacteria living in Earth’s clouds. They’re tolerant little beasts too, living in dry conditions, surviving high levels of ultraviolet light and low levels of oxygen. They’re even thought to help clouds to form, particularly in warmer climates.
On Venus, you might think that the potent acid which makes up the clouds may be a hindrance to any kind of Venusian microbes that may live there, but there are extremophile bacteria on Earth that live in similar conditions. One form of bacteria live in caves (the unappealingly named snottites), where they metabolise sulfur and create sulfuric acid. These bacteria create, and thrive in, acid as strong as what you might find in a car battery.
One scientist who’s given a lot of thought to life in unusual environments is Dirk Schulze-Makuch, currently at Washington State University. Something which he and his colleagues were interested by is the fact that the clouds of Venus seem to absorb more ultraviolet light than they should.
Being about 42 million kilometers (26 million miles) closer to the sun than Earth, the upper atmosphere of Venus is bombarded by enough ultraviolet to give lethal sunburn to anything without adequate protection. However, one idea is that molecular rings of sulfur could be giving something just that kind of protection.
Sulfur is plentiful in the atmosphere of Venus, and in its elemental form it likes to make molecules, each containing 8 sulfur atoms. Known as cyclo-octasulfur, these molecules absorb harmful UV and radiate it away at less harmful wavelengths. Could we be seeing sulfur sunblock? Perhaps, but then again perhaps not. Either way, whatever it is which is absorbing all that UV still hasn’t been conclusively identified.
Chemically, there’s definitely some mystery lurking in those beautiful clouds. Certain molecules are found there which shouldn’t be found together. Two in particular, sulfur dioxide (SO2) and hydrogen sulfide (H2S) shouldn’t be found together — when in the same place, they react with each other. The only conclusion is that, somehow, something on Venus must be creating them, otherwise there’d be none for us to see.
Another unexpected chemical in Venus’ atmosphere is known as carbonyl sulfide (OCS). On Earth, carbonyl sulfide is so difficult to create through inorganic processes that it’s been used as an “unambiguous indicator of biological activity“.
There’s one final piece in this bizarre acidic puzzle. The so-called “mode 3 cloud particles.” The clouds of Venus, much like the clouds on any other planet, are a menagerie of tiny droplets and ice crystals made up of the various chemicals found in the atmosphere. These cloud particles are normally fairly easy to identify, but the mode 3 particles are still a mystery.
They’re large, non-spherical, and they contain plenty of sulfuric acid. While it would be ridiculous to make any wild claims, it’s worth considering that those cloud particles are even the same size as bacteria — a notion that David Grinspoon, curator of astrobiology at the Denver Museum of Nature and Science, discussed in his book, Venus Revealed.
Of course, I’m not saying that there actually is life in the vitriolic Venusian clouds. There’s no way anyone could say that for certain, and there are still a lot of criticisms of the idea. The biggest sticking point being the lack of water — while there is some water in those clouds, it’s certainly scarce. All the same, there is something going on on that planet that Venus isn’t telling us. And it doesn’t seem like it’s going to give up its mysteries just yet.
Most people aren’t too keen on the idea that Earth’s “evil twin” may actually be a home to life, but you have to admit that all the evidence I’ve written about here gives some compelling food for thought. Venus is normally dismissed immediately when talking about alien life. Perhaps we shouldn’t give up on the big acid ball just yet.
Quelle: DNEWS

3178 Views

Donnerstag, 16. Mai 2013 - 23:25 Uhr

Raumfahrt - ULA startet Atlas V Rocket mit GPS IIF-4 Satellit

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15.05.2013

CAPE CANAVERAL, Fla — United Launch Alliance (ULA) is preparing to launch an Atlas V 401 rocket with the Air Force’s Global Positioning System (GPS) IIF-4 from Cape Canaveral Air Force Station’s Space Launch Complex 41 (SLC-41) in Florida. Launch is currently set to take place May 15 at 5:38 p.m. EDT. The launch window only extends for 18 minutes. If you are in town and have never watched a launch before, here’s your chance for a rare opportunity.
But where? Which spots provide the best viewing opportunities? Which ones are horrible? What if you’re on a budget? Not all locations are ideal, and while one spot might be perfect to view a certain launch vehicle, given the sheer amount of terrain that Cape Canaveral covers, another location might provide poor viewing.
One of the best spots for those that want to view the launch in person is Playalinda Beach. This is due to the virtually unobstructed view of SLC-41 and, therefore, the Atlas rocket. It only costs $5 to enter the park, which closes at sunset and provides for plenty of time to view this launch. The park can be contacted at: 321-267-1110
For those taking a cruise, Port Canaveral is also a popular viewing spot. In actuality, one can stop at almost any point on SR-528 or SR-401 behind the Port to gain a clear view of launch, as well as to experience the thrill of hearing the roar of the RD-180 engines powering it aloft. Even at a distance of 10 miles you can still hear the rocket’s engines throttle loudly into the black.
Quelle: ULA
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Update: 16.05.2013
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  • Posted at 6:01 PM EDT, 05/15/13: Atlas 5 boosts GPS navsat into space
  • Updated at 09:25 PM EDT, 05/15/13: Satellite separation; mission declared successful

A United Launch Alliance Atlas 5 rocket boosted a new Global Positioning System satellite into orbit Wednesday, the latest in a series of upgraded navigation beacons with improved accuracy and longevity.

The Atlas 5's RD-180 first stage engine roared to life and throttled up at 5:38 p.m. EDT (GMT-4), pushing the 188-foot-tall booster away from launch complex 41 at the Cape Canaveral Air Force Station with 860,000 pounds of thrust.
Burning more than a ton of liquid oxygen and highly refined kerosene per second, the rocket quickly accelerated, climbing away on a northeasterly trajectory atop a rushing torrent of fiery exhaust visible for miles around.
The first stage shut down four minutes and four seconds after liftoff and fell away, followed seconds later by ignition of the Centaur's hydrogen-fueled second stage engine.
Generating 22,300 pounds of push, the Pratt & Whitney RL10A engine burned for nearly 13 minutes to put the spacecraft in a preliminary near-circular orbit at an altitude of about 11,050 miles. A second 1.5-minute firing was planned three hours later to put the payload in its operational orbit.
The $121.3 million GPS 2F-4 satellite, the fourth in a series of 12 being built by Boeing, was released from the Centaur second stage three hours and 24 minutes after launch. In a news release, United Launch Alliance declared the launching a success.
Following tests and checkout operations, the 3,600-pound solar-powered satellite will be turned over to the Air Force for operational use.
The new satellite joins a constellation of 30 other Global Positioning System navigation stations operating in six different orbital planes. At least four satellites fly in each plane and multiple spacecraft are above the horizon at any given moment as viewed from any point on Earth.
Each satellite transmits signals that specify its exact orbital location and the exact time, using ultra-precise on-board atomic clocks.
Combining the signals from four or more visible satellites, GPS receivers on the ground, at sea and in the air can compute a user's position, altitude and velocity. Encrypted high-precision military signals are available, along with a slightly less precise public signal used in a wide variety of commercial applications.
The GPS 2F series provide "greater navigational accuracy through improvements in atomic clock technology, a more secure and jam-resistant military signal, an improved (system) that will eventually assist in commercial aviation and search-and-rescue operations, and an onboard reprogrammable processor," said Jan Heide, Boeing program director. "And this is with a 12-year design life for long-term service and reduced operating costs."
Col. Steve Steiner, chief of the Air Force's GPS Space Systems Division in Los Angeles, said the satellites "provide precision, day or night, all-weather, guidance and timing to numerous platforms and weapons that we have."
"GPS is critical to how we fight wars on land, sea and air," he told reporters in a pre-launch news briefing. "Space systems truly are an embedded part of how the U.S. military operates these days."
And the same goes for more familiar commercial applications.
"The timing capabilities of the vehicle are also integral to the U.S. economy," Heide said. "Every ATM transaction that happens essentially is facilitated by GPS timing capabilities. Cellphone is another fantastic example. The ability to walk up and pay at the pump to get gas, fantastic capability.
"It's almost integrated into everything that current societies are accustomed to having," he added. "It's like telephone utility service that people just have an expectation that the satellite and the mission capability are going to be there for them."
Quelle: CBS
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Frams: Start-Video ULA
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2891 Views

Donnerstag, 16. Mai 2013 - 09:05 Uhr

Astronomie - Cassini liefert Daten für erste Titan-Karte

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Polar Views of Titan's Global Topography
These polar maps show the first global, topographic mapping of Saturn's moon Titan, using data from NASA's Cassini mission. To create these maps, scientists employed a mathematical process called splining, which uses smooth curved surfaces to "join" the areas between grids of existing topography profiles obtained by Cassini's radar instrument. The topography maps at bottom focus on the polar regions (north at left, south at right) in stereographic projection. The top maps show the 2-D radar data in gold and black, with topography data color-coded by elevation. The bottom images are from the new topography map, with contour lines added at 656 feet (200 meters) apart in elevation.
Visible are deep basins at 72 degrees south latitude and 20 degrees east longitude, and a wider basin at 68 degrees south latitude and 105 degrees east longitude.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and ASI, the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the US and several European countries.
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Scientists have created the first global topographic map of Saturn's moon Titan, giving researchers a valuable tool for learning more about one of the most Earth-like and interesting worlds in the solar system. The map was just published as part of a paper in the journal Icarus. 
Titan is Saturn's largest moon - with a radius of about 1,600 miles (2,574 kilometers), it's bigger than planet Mercury - and is the second-largest moon in the solar system. Scientists care about Titan because it's the only moon in the solar system known to have clouds, surface liquids and a mysterious, thick atmosphere. The cold atmosphere is mostly nitrogen, like Earth's, but the organic compound methane on Titan acts the way water vapor does on Earth, forming clouds and falling as rain and carving the surface with rivers. Organic chemicals, derived from methane, are present in Titan's atmosphere, lakes and rivers and may offer clues about the origins of life. 
"Titan has so much interesting activity - like flowing liquids and moving sand dunes - but to understand these processes it's useful to know how the terrain slopes," said Ralph Lorenz, a member of the Cassini radar team based at the Johns Hopkins University Applied Physics Laboratory, Laurel, Md., who led the map-design team. "It's especially helpful to those studying hydrology and modeling Titan's climate and weather, who need to know whether there is high ground or low ground driving their models." 
Titan's thick haze scatters light in ways that make it very hard for remote cameras to "see" landscape shapes and shadows, the usual approach to measuring topography on planetary bodies. Virtually all the data we have on Titan comes from NASA's Saturn-orbiting Cassini spacecraft, which has flown past the moon nearly 100 times over the past decade. On many of those flybys, Cassini has used a radar imager, which can peer through the haze, and the radar data can be used to estimate the surface height. 
"With this new topographic map, one of the most fascinating and dynamic worlds in our solar system now pops out in 3-D," said Steve Wall, the deputy team lead of Cassini's radar team, based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "On Earth, rivers, volcanoes and even weather are closely related to heights of surfaces - we're now eager to see what we can learn from them on Titan." 
There are challenges, however. "Cassini isn't orbiting Titan," Lorenz said. "We have only imaged about half of Titan's surface, and multiple 'looks' or special observations are needed to estimate the surface heights. If you divided Titan into 1-degree by 1-degree [latitude and longitude] squares, only 11 percent of those squares have topography data in them." 
Lorenz's team used a mathematical process called splining - effectively using smooth, curved surfaces to "join" the areas between grids of existing data. "You can take a spot where there is no data, look how close it is to the nearest data, and use various approaches of averaging and estimating to calculate your best guess," he said. "If you pick a point, and all the nearby points are high altitude, you'd need a special reason for thinking that point would be lower. We're mathematically papering over the gaps in our coverage." 
The estimations fit with current knowledge of the moon - that its polar regions are "lower" than areas around the equator, for example - but connecting those points allows scientists to add new layers to their studies of Titan's surface, especially those modeling how and where Titan's rivers flow, and the seasonal distribution of its methane rainfall. "The movement of sands and the flow of liquids are influenced by slopes, and mountains can trigger cloud formation and therefore rainfall. This global product now gives modelers a convenient description of this key factor in Titan's dynamic climate system," Lorenz said. 
The most recent data used to compile the map is from 2012; Lorenz says it could be worth revising when the Cassini mission ends in 2017, when more data will have accumulated, filling some of the gaps in present coverage. "We felt we couldn't wait and should release an interim product," he says. "The community has been hoping to get this for a while. I think it will stimulate a lot of interesting work." 
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and ASI, the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries.
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To create the first global, topographic map of Saturn's moon Titan, scientists analyzed data from NASA's Cassini spacecraft and a mathematical process called splining. This method effectively uses smooth curved surfaces to "join" the areas between grids of existing topography profiles obtained by Cassini's radar instrument. In the upper panel of this graphic, gold colors show where radar images have been obtained over almost half of Titan's surface. Image credit: NASA/JPL-Caltech/ASI/JHUAPL/Cornell/Weizmann
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Quelle: NASA

3218 Views

Donnerstag, 16. Mai 2013 - 08:49 Uhr

Astronomie - Das verborgene feurige Band des Orion

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Dieses indrucksvolle neue Bild kosmischer Wolken im Sternbild Orion offenbart etwas, das wie ein feuriges Band am Himmel aussieht. Das orangene Glimmen stellt ein schwaches Leuchen dar, das von kaltem interstellarem Staub stammt und dessen Wellenlänge zu groß ist, um für das menschliche Auge sichtbar zu sein. Das Bild wurde mit dem Atacama Pathfinder Experiment (APEX) in Chile beobachtet, das von der ESO betrieben wird.
In diesem Bild wurde das Leuchten des Staubs im Submillimetebereich mit einer vertrauteren Aufnahme der Himmelsregion im sichtbaren Licht vom Digitized Sky Survey überlagert. Die große, helle Wolke oben rechts im Bild ist der berühmte Orionnebel, auch Messier 42 genannt.
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Wolken aus interstellarem Gas und Staub sind das Rohmaterial, aus dem Sterne entstehen. Allerdings verbergen die winzigen Staubkörnchen all das, was in oder hinter diesen Wolken liegt. Dies wiederum erschwert das Beobachten von Sternentstehungsprozessen. Zumindest gilt das für den sichtbaren Bereich des Lichts.
Aus diesem Grund verwenden Astronomen Instrumente, die es ermöglichen, bei anderen Wellenlängen des Lichts zu beobachten. Im Submillimeterbereich beispielsweise strahlen die Staubteilchen wegen ihrer Temperatur von einigen zehn Grad über dem absoluten Nullpunkt [1], anstatt das Licht zu blockieren. Das APEX-Teleskop, das sich in einer Höhe von 5000 Metern über dem Meeresspiegel auf dem Chajnantor-Plateau befindet, und seine Kamera LABOCA, die bei Submillimeterwellenlängen empfindlich ist, sind ideal, um solche Beobachtungen durchzuführen.
Das spektakuläre neue Bild zeigt nur einen Teil eines größeren Komplexes im Sternbild Orion, das man die Orion-Molekülwolke nennt. Dieses Gebiet ist ein unerschöpflicher Schmelztiegel aus hellen Nebeln, heißen, jungen Sternen und kaltem Staub, hat einen Durchmesser von mehreren Hundert Lichtjahren und ist etwa 1320 Lichtjahre von uns entfernt. Das Leuchten im Submillimeterbereich stammt von den kalten Staubwolken, die in diesem Bild orange dargestellt sind, und wurde mit einer vertrauteren Aufnahme dieser Himmelsregion im sichtbaren Licht überlagert.
Die große, helle Wolke oben rechts im Bild ist der berühmte Orionnebel, auch Messier 42 genannt. Er ist bereits mit bloßem Auge als ein etwas verschwommenes, sternähnliches Gebilde im Schwert des Orion zu sehen. Der Orionnebel ist aber nur der hellste Teil einer riesigen Sternkinderstube, in der nach wie vor neue Sterne geboren werden. Er ist von der Erde aus gesehen der nächste Ort, an dem Sternentstehung stattfindet.
Die Staubwolken bilden wunderschöne Filamente, Streifen und Blasen, die durch Prozesse wie den gravitativen Kollaps oder die Einwirkungen von Sternwinden entstehen. Solche Winde sind Strömungen von ausgestoßenem Gas aus Atmosphären der Sterne. Sie sind stark genug, um die umgebenden Wolken in die gebogenen Strukturen zu bringen, die wir sehen.   
Astronomen haben mit Hilfe dieser und weiterer Daten von APEX zusammen mit Bildern des Herschel-Weltraumteleskops der ESA nach sogenannten Protosternen, einem frühen Stadium der Sternentstehung, im Gebiet des Orion gesucht. Bisher waren sie in der Lage, 15 solcher Objekte zu identifizieren, die bei längeren Wellenlängen viel heller erscheinen als bei kürzeren. Diese neu entdeckten, seltenen Objekte gehören vermutlich zu den jüngsten Protosternen, die jemals gefunden wurden. Diese Entdeckung bringt Astronomen dem Ziel näher, den Moment mitzuerleben, an dem ein Stern überhaupt erst anfängt sich zu bilden.
Endnoten
[1] Heiße Objekte geben den größten Anteil ihrer Strahlung bei kürzeren Wellenlängen und kältere Objekte bei längeren Wellenlängen ab. So sehen zum Beispiel heiße Sterne (mit Temperaturen von ca. 20.000 Kelvin) blau aus. Dagegen sehen kühlere Sterne (mit Temperaturen um die 3000 Kelvin) rot aus. Eine Staubwolke mit einer Temperatur von nur zehn Kelvin hat somit ihr Emissionsmaximum bei einer viel längeren Wellenlänge – etwa 0,3 Millimeter – also in dem Teil des elektromagnetischen Spektrums, in dem APEX sehr empfindlich ist.
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Diese Übersichtsaufnahme zeigt die Himmelsregion um den Reflexionsnebel NGC 1999 im berühmten Sternbild Orion im sichtbaren Licht. NGC 1999 liegt in der Bildmitte. Das große, helle Objekt am oberen Bildrand ist der bekannte Orionnebel (Messier 42). Das Bild wurde aus Daten des Digitized Sky Survey 2 erstellt.
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Quelle: ESO

3010 Views

Donnerstag, 16. Mai 2013 - 08:36 Uhr

Raumfahrt - Dream Chaser Raumschiff beginnt mit Flug-Test

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Sierra Nevada Corporation’s Dream Chaser spacecraft arrived at NASA’s Dryden Flight Research Center, wrapped in plastic and looking a bit like an enormous swordfish, to be prepared for its first test flights.
Dream Chaser is one of three vehicles being developed under  NASA’s Commercial Crew Program, which will launch astronauts to the International Space Station and low-earth orbit later this decade. The lifting body vehicle will be reassembled at Dryden over the coming weeks, then begin flight testing next door on the dry lake bed at Edwards Air Force Base in Southern California.
“This will be the first full scale flight test of the Dream Chaser lifting body and will demonstrate the unique capability of our spacecraft to land on a runway,” Sierra Nevada’s Jim Voss said in a statement. “Other flight tests will follow to validate the aerodynamic data used to control the vehicle in the atmosphere when it returns from space.”
The Dream Chaser is the only orbital space vehicle currently in testing that will land like a glider after reentry from space. It is based on lifting body vehicles dating to the 1960s, including NASA’s M2-F2 made famous in the opening sequence of the Six Million Dollar Man. It is a more direct descendent of NASA’s HL-20, a newer lifting body design developed in the 1990s.
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Since the retirement of the space shuttle, the United States has relied upon Russia’s Soyuz vehicles to get people into orbit. NASA just extended its contract with the Russians, paying an additional $424 million to provide transportation to the International Space Station for six U.S. astronauts through 2017.
Sierra Nevada, Boeing and SpaceX are developing vehicles to fly astronauts to low earth orbit for NASA. Boeing and SpaceX are developing capsule spacecraft that will return to earth under parachute, while the Dream Chaser will return much like the space shuttle orbiters.
After several years of development, wind tunnel testing and refinement, the Dream Chaser team completed its first major safety review with NASA last month. On Sunday, the vehicle was loaded onto a truck at the company’s facility in Colorado and driven west. The team will spend several weeks reassembling the spacecraft and begin a series of ground-based tests, including a tow down the runway to evaluate the landing gear and brakes and a resonance test.
Eventually the Dream Chaser will begin flight tests, starting with a “captive carry” flight suspended beneath a helicopter and autonomous free flights to test the approach and landing system. The flight test vehicle will be dropped from an Erickson Air-crane.While the Dream Chaser is being assembled in the Mojave desert, NASA astronauts in Hampton, Virginia will begin flying simulations of its approach and landing pattern to further evaluate the vehicle’s handling. Using the simulator will allow the team at NASA’s Langley Research Center to “fly” the Dream Chaser in a wide range of atmospheric conditions, as well as several different flight scenarios.
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Tags: Dream Chaser 

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