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Sonntag, 21. September 2014 - 17:55 Uhr

Raumfahrt - Sternenhimmel aus der Raumstation

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Starry Sky from the Space Station
ISS041-E-009477 (13 Sept. 2014) --- One of the Expedition 41 crew members aboard the Earth-orbiting International Space Station on Sept. 13, 2014 captured this image of a starry sky. The white panel at left belonging to the ATV-5 spacecraft, which is docked with the orbital outpost, obstructs the view of Scorpius. The red star Antares is directly to the left of the bottom of the second ATV panel from the top. The two stars that are close together and on the lower left of the photo comprise Shaula, the tip of the scorpion’s tail. The open cluster close to Shaula is M7. The hardware at bottom right is part of one of the station's solar panels.
Image Credit: NASA

Tags: Raumfahrt 

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Sonntag, 21. September 2014 - 09:05 Uhr

Raumfahrt - Sowjet-Ära Kosmonaut Anatoly Berezovoy (Raumstation Saljut) gestorben.

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Anatoly Berezovoy, who in 1982 spent 211 days working aboard a Russian space station, died Sept. 20. He was 72. (Roscosmos)
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Sep. 20, 2014 - Soviet-era cosmonaut Anatoly Berezovoy, who led the first expedition on board Russia's final Salyut space station, died Saturday (Sept. 20). He was 72.
"[Berezovoy] was a member of a legendary generation of cosmonauts, a man of great will and courage, [and] a top-class professional who did so much for the development of cosmonautics and major research projects," said Oleg Ostapenko, the chief of the Russian federal space agency Roscosmos. "His memory will live on forever in the hearts of those who knew and loved [him]."
Chosen to be a cosmonaut in April 1970, Berezovoy made his first and only spaceflight 12 years later as commander of the Soyuz T-5 mission to the Salyut 7 space station. Launched on May 13, 1982, Berezovoy and FLIGHTengineer Valentin Lebedev spent a then-record 211 days aboard the orbiting outpost, which was the last of its type before the launch of the Mir space station in 1986.
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Anatoly Berezovoy and Valentin Lebedev were the first residents onboard the Soviet Union's Salyut 7 space station. (Roscosmos)
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During his expedition, which was flown under the call sign "Elbrus," Berezovoy and Lebedev operated cameras and a telescope, materials processing furnace, and plant growth chamber. The two crewmates also deployed a small radio communications satellite, which the Soviet Union claimed as the world's first satellite to be deployed from a manned spacecraft (NASA's space shuttle Columbia would launch with two communication SATELLITES on the STS-5 mission later that same year).
Berezovoy and Lebedev also made a two-hour, 33-minute spacewalk on July 30, 1982, to retrieve material exposure samples and replace equipment.
The two cosmonauts were visited by four robotic resupply ships and two crews. Among Berezovoy's and Lebedev's temporary crew members were the first French citizen to fly in space, Jean-Loup Chrétien, and the second woman in space, Soviet cosmonaut Svetlana Savitskaya, as well as Vladimir Dzhanibekov, Alexander Ivanchenkov, Leonid Popov and Alexander Serebrov.
Berezovoy and Lebedev returned to Earth from the Salyut 7 space station on Dec. 10, 1972 on board the Soyuz T-7 spacecraft. Touching down in heavy snow and on uneven land, which caused their capsule to roll down a slope, the two cosmonauts — already weak from being in space for so long — spent the night with recovery personnel, waiting for a helicopter to come the next day.
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Anatoly Berezovoy floats onboard the Salyut 7 space station with the second woman in space, Svetlana Savitskaya. (Roscosmos)
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In total, Berezovoy logged 211 days, 9 hours, 4 minutes in space.
Although he served as a back-up commander for several other Soyuz FLIGHTS, Berezovoy did not fly again. He retired from the cosmonaut corps in October 1992 after suffering injuries in an armed robbery.
Anatoly Nikolayevich Berezovoy was born April 11, 1942, to a Ukrainian family in the Russian village of Enem. He attended the A.F. Masnikovin military flying school, where he graduated in 1965.
During his time on Salyut 7, Berezovoy penned a 92-page diary, in which he RECORDED his space experiences for his wife, Lidia Grigorievna, and their two children, Sergei and Tatiana (then 13 and 8 years old, respectively).
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Anatoly Berezovoy and Valentin Lebedev train onboard a Soyuz T simulator prior to their 1982 FLIGHT on Soyuz T-5. (Roscosmos)
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"For a long time I've been trying to write about everything that has moved me during these days passed in FLIGHT," Berezovoy wrote to begin the journal on June 22, 1982, a month into his 7-month stay, according to spacediary.info, which has offered the original hand-written diary for sale. "There is a lot of work to be done."
After leaving the cosmonaut corps, Berezovoy served as vice president of the Cosmonautics Federation of Russia from 1992 to 1999. In 1995, he campaigned for a seat in Russia's parliament representing the Republic of Adygea, but lost in the election.
Berezovoy was honored as a Hero of the Soviet Union and bestowed the Order of Lenin for his service to his country as a cosmonaut.
Quelle: SC
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Quelle: Salyut-7 Roscosmos

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Samstag, 20. September 2014 - 20:00 Uhr

Astronomie - Die gewaltsame Entstehung von Scheibengalaxien

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Neue ALMA-Beobachtungen erklären warum milchstaßenähnliche Galaxien im Universum so häufig vorkommen

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Jahrzehntelang glaubten Wissenschaftler, dass die Verschmelzung von Galaxien normalerweise zur Entstehung von ELLIPTISCHEN Galaxien führt. Nun haben Forscher zum ersten Mal mit Hilfe von ALMA und einer Reihe weiterer Radioteleskope einen direkten Beweis dafür gefunden, dass kollidierende Galaxien stattdessen Scheibengalaxien hervorbringen können, und dass dieser Ausgang in der Tat recht häufig ist. Dieses überraschenden Ergebnis könnte erklären, warum es im Universum so viele Spiralgalaxien wie die Milchstraße gibt.
Ein internationales Forscherteam unter der Leitung von Junko Ueda, einem promovierten wissenschaftlichen Mitarbeiter der Japan Society for the Promotion of Science, hat die überraschende Beobachtung gemacht, dass die meisten Zusammenstöße von Galaxien im nahen Universum – innerhalb von 40-600 Millionen Lichtjahren von der Erde – zu sogenannten Scheibengalaxien führen. Scheibengalaxien – einschließlich Spiralgalaxien wie der Milchstraße und linsenförmiger Galaxien – zeichnen sich durch ihre Pfannkuchenform mit Gebieten aus Gas und Staub aus und unterscheiden sich von der Klasse der elliptischen Galaxien.
Schon einige Zeit lang herrschte die Meinung vor, dass kollidierdende Scheibengalaxien letzten Endes ellipsenförmige Galaxien bilden. Während dieser heftigen Wechselwirkungen nehmen die Galaxien nicht nur an Masse zu, während sie miteinander verschmelzen beziehungsweise einander auffressen, sondern ändern ihre Form und damit auch ihren Typ auf kosmischen Zeitskalen.
Computersimulationen aus den 1970ern zufolge würden Kollisionen zweier vergleichbarer Scheibengalaxien in einer elliptischen Galaxie resultieren. Nach diesen Simulationen müssten die meisten heutigen Galaxien ELLIPTISCH sein, was der Beobachtung dass 70% der Galaxien aber in Wirklichkeit Scheibengalaxien sind widerspricht. Neuere Simulationen deuten allerdings darauf hin, dass solche Kollisionen auch Scheibengalaxien hervorbringen können.
Um die letztendliche Form von Galaxien nach Verschmelzungen durch Beobachtungen zu ermitteln, hat das Team die Verteilung von Gas in 37 Galaxien untersucht, die sich in ihrer letzten Verschmelzungsphase befinden. Mit dem Atacama Large Millimeter/sub-millimeter Array (ALMA) und einigen weiteren Radioteleskopen [1] wurde die Emission von Kohlenstoffmonoxid (CO) untersucht, einem Indikator für molekulares Gas.
Die Arbeit dieser Gruppe stellt die bislang größte Untersuchung molekularen Gases in Galaxien dar und liefert einzigartige Einblicke in die Art und Weise, wie die Milchstraße entstanden sein könnte. Ihre Studie enthüllte, dass fast alle Galaxienverschmelzungen in pfannkuchenförmigen Gebiete molekularen Gases resultieren und es sich daher um Scheibengalaxien in der Entstehung handelt. Ueda erklärt: „Zum ersten Mal gibt es beobachtbare Nachweise für verschmelzende Galaxien, die zu Scheibengalaxien werden könnten. Das ist ein großer und unerwarteter Schritt zur Lösung des Rätsels um die GEBURT von Scheibengalaxien.”
Nichtsdestotrotz gibt es noch viel mehr zu entdecken. Ueda ergänzt: „Wir müssen anfangen uns auf die Sternentstehung in diesen Gasscheiben zu konzentrieren. Außerdem müssen wir in das weiter entfernte Universum hinausblicken: Wir wissen, dass die meisten Galaxien im ferneren Universum ebenfalls Scheiben besitzen. Wir wissen jedoch noch nicht, ob Galaxienverschmelzungen auch dafür verantwortlich sind oder ob sie durch kaltes, in die Galaxie einfallendes Gas entstanden sind. Vielleicht haben wir einen allgemeinen Mechanismus gefunden, der für die gesamte Geschichte des Universums gilt.” 
Endnoten
[1] Die folgenden Teleskope waren an den Beobachtungen beteiligt: ALMA, das Combined Array for Research in Millimeter-wave Astronomy: eine Anordnung von 23 parabolischen Antennenschüsseln in Kalifornien, die im Millimeterwellenbereich beobachtet; das  Submillimeter Array: eine Anordnung von acht parabolischen Antennenschüsseln in Mauna Kea auf Hawaii, das im Submillimeterbereich beobachtet; das Plateau de Bure Interferometer; das  NAOJ Nobeyama Radio Observatory 45-Meter-Radioteleskop; das National Radio Astronomy Observatory 12-Meter-Teleskop der USA; das Five College Radio Astronomy Observatory 14-Meter-Teleskop der USA; das 30-Meter-Teleskop des IRAM und ergänzend das Swedish-ESO Submillimeter Telescope.
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Jedes der bunten Objekte in diesem Bild stellt eine von 30 verschmelzenden Galaxien dar. DIE KONTUREN in den einzelnen Galaxien stellen die Verteilung von Kohlenstoffmonoxid dar, während die Farbe die Gasbewegung repräsentiert. Gas, das sich von uns entfernt, erscheint rot, wohingegen blau das Gas anzeigt, das sich auf uns zu bewegt. Die Konturen zusammen mit den Übergängen von rot zu blau stellen eine Gasscheibe dar, die um das Galaxiezentrum rotiert.
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Quelle: ESO

Tags: Astronomie 

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Samstag, 20. September 2014 - 09:12 Uhr

Astronomie - ESA´s Mars-Express sieht den Winter bei ARGYRE

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Over billions of years, the southern uplands of Mars have been pockmarked by numerous impact features, which are often so closely packed that they overlap. One such feature is Hooke crater, shown in this frost-tinged scene, imaged by ESA’s Mars Express during winter in the southern hemisphere.

Hooke crater is located near the northern edge of the 1800 km-wide Argyre basin – one of the most impressive impact structures on Mars, excavated in a giant collision about 4 billion years ago.
Sitting in a FLAT part of the basin known as Argyre Planitia, Hooke crater has a diameter of 138 km and a maximum depth of about 2.4 km. It is named after the English physicist and astronomer Robert Hooke (1635–1703).
Hooke crater comprises two different impact structures, with a smaller impactor blasting a DEPRESSION off-centre in the floor of a larger, pre-existing crater. The newer crater in the centre is filled with a large mound topped by a dark dune field. The mound appears to be composed of layered material, possibly alternating sheets of sand and frost.
Dark dunes also spread southwards (to the left in the topographic, main colour and 3D images) from the smaller crater, partially covering the floor of the main crater. The local topography modifies the airflow, serving as a sand trap for the wind-blown sediments.
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Hooke crater is located at about 46°S / 316°E, near the northern edge of the 1800 km-wide Argyre basin, one of the most impressive impact structures on Mars. The crater, with diameter 138 km and a maximum depth of about 2.4 km, is situated in a FLAT region within the basin known as Argyre Planitia.
The region was imaged by the High Resolution Stereo CAMERA on Mars Express on 20 April 2014 during orbit 13 082. The smaller rectangle above outlines the region highlighted in the associated Mars Express images.
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Colour-coded topography map of a region of the Argyre basin, featuring Hooke crater and part of the floor of the basin known as Argyre Planitia. White and red show the highest terrains, while blue and purple show the deepest. The image is based on a digital terrain model of the region, from which the topography of theLANDSCAPE can be derived. The region clearly slopes to the south (left).
The image was acquired by the High Resolution Stereo CAMERAon Mars Express on 20 April 2014 during orbit 13 082. The ground resolution is about 63 m per pixel. Hooke crater is located at about 46°S / 316°E.  North is right and East is down.
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In these images, much of the low-lying region to the south, as well as the central mound inside Hooke crater, is covered with a thin, white coating of carbon dioxide frost. At higher elevations and on north-facing crater walls, the frost is largely absent and appears only in areas shaded from direct sunlight by the walls of smaller craters.
Outside the crater, there are a number of linear features visible on the floor of Argyre Planitia, on the south (left) side of the topographic, main colour and 3D images. These are examples of ‘yardangs’, rocky ridges that have been shaped by prolonged wind erosion. Most of the yardangs are oriented towards Hooke crater, indicating the prevailing wind direction.
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Also visible on the floor of the Argyre basin are small areas of chaotic terrain, which resembleDEPRESSIONS containing flat-topped mesas, buttes and hills. In the topographic, main colour and 3D images, one of these regions can be seen at the top edge, about a third of the way from the left, and another in the lower middle part, down from the left-most edge of the crater.
Chaotic terrains like these are thought to have been created when large-scale melting of ground ice caused the ground to collapse. Where the terrain has not collapsed completely, the larger mesas may still contain substantial water ice.
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Clearly, this region has been greatly modified by natural forces since the dramatic impacts billions of years ago that formed the Argyre basin and, later, the pair of Hooke craters.
Quelle: ESA

Tags: Astronomie 

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Freitag, 19. September 2014 - 08:00 Uhr

Astronomie - Uranus Mond Miranda: Ein Eisiger Mond durch Gezeiten-Wärme deformiert

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Mosaic of southern hemisphere of Miranda, the innermost regular satellite of Uranus, with radius of 236 km. Projection is orthographic, centered on the south pole. Visible from left to right are Elsinore, Inverness, and Arden coronae. Image credit: NASA/Jet Propulsion Laboratory/Ted Stryk.

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Boulder, Colo., USA – Miranda, a small, icy moon of Uranus, is one of the most visually striking and enigmatic bodies in the solar system. Despite its relatively small size, Miranda appears to have experienced an episode of intense resurfacing that resulted in the formation of at least three remarkable and unique surface features -- polygonal-shaped regions called coronae.
These coronae are visible in Miranda’s southern hemisphere, and each one is at least 200 km across. Arden corona, the largest, has ridges and troughs with up to 2 km of relief. Elsinore corona has an outer belt that is approx. 80 km wide, relatively smooth, and elevated above the surrounding terrain by approx. 100 m. Inverness corona has a trapezoidal shape with a large, bright chevron at its center. The northern hemisphere of Miranda was never imaged by the Voyager 2 spacecraft, so it is unknown whether additional coronae exist.
Using numerical models, Noah Hammond and Amy Barr show that convection in Miranda's ice mantle likely formed the coronae. During convection, warm buoyant ice rose toward the surface, driving concentric surface extension beneath the locations of the coronae, causing the formation of extensional tectonic faults. This style of resurfacing is similar to plate tectonics on Earth, in that convection is a primary driving force for surface deformation.
Hammond and Barr write that the internal energy that powered convection probably came from tidal heating. Tidal heating would have occurred when Miranda was in an eccentric orbit -- moving closer to and further from Uranus. This caused the tidal forces from Uranus to vary, periodically stretching and squeezing Miranda and generating heat in its ice shell. Hammond and Barr find that convection powered by tidal heating explains the locations of the coronae, the deformation patterns within the coronae, and the estimated heat flow during corona formation.
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Global resurfacing of Uranus's moon Miranda by convection
Noah P. Hammond1 and Amy C. Barr1
Abstract
Miranda, an icy moon of Uranus, is one of the most visually striking and enigmatic bodies in the solar system. Three polygonal-shaped regions of intense deformation, dubbed "coronae," dominate the surface of Miranda. Here we use numerical methods to show that sluggish-lid convection in Miranda's ice shell, powered by tidal heating, can simultaneously match the global distribution of coronae, the concentric deformation pattern, and the estimated heat flow during formation. The expected rheological conditions in Miranda's ice shell lead to the development of low-order convection that produces surface deformation patterns similar to those observed. We find that satellite core size strongly controls convection geometry and that low-order convection patterns are much more stable for core radii less than half the satellite radius.
Quelle: The Geological Society of America (GSA)

Tags: Astronomie 

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Freitag, 19. September 2014 - 08:00 Uhr

Astronomie - Neue Ergebnisse von AMS-Experiment auf ISS

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The Alpha Magnetic Spectrometer (link is external) (AMS) collaboration has today presented its latest results. These are based on the analysis of 41 billion particles detected with the space-based AMS detector aboard the International Space Station. The results, presented during a seminar at CERN, provide new insights into the nature of the mysterious excess of positrons (antielectrons) observed in the flux of cosmic rays. The findings are published today in the journal Physical Review Letters.
The AMS experiment is able to map the flux of cosmic rays with unprecedented precision and in the results published today, the collaboration presents new data at energies never before recorded. The AMS collaboration has analysed 41 billion primary cosmic-ray events among which 10 million have been identified as electrons and positrons. The distribution of these events in the energy range of 0.5 to 500 GeV shows a well-measured increase of positrons from 8 GeV with no preferred incoming direction in space. The energy at which the positron fraction ceases to increase has been measured to be 275±32 GeV.
This rate of decrease after the “cut-off energy” is very important to physicists as it could be an indicator that the excess of positrons is the signature of dark-matter particles annihilating into pairs of electrons and positrons. Although the current measurements could be explained by objects such as pulsars, they are also tantalizingly consistent with dark matter particles with mass of the order of 1 TeV.  Different models on the nature of dark matter predict different behaviour of the positron excess above the positron fraction expected from ordinary cosmic ray collisions. Therefore, results at higher energies will be of crucial importance in the near future to evaluate if the signal is from dark matter or from a cosmic source.
Quelle: CERN

Tags: Astronomie 

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Donnerstag, 18. September 2014 - 21:58 Uhr

Raumfahrt - United Launch Alliance und Blue Origin entwickeln gemeinsam neuen amerikanischen Raketenmotor

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ULA Teams With Blue Origin for New Rocket Engine
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WASHINGTON — The United Launch Alliance (ULA) is teaming with Seattle-based Blue Origin to design and produce a next-generation, American-made rocket engine for space launch, the companies announced Wednesday.
While the engine will be designed for multiple missions, the agreement is a clear move by ULA to develop an American-made replacement for the RD-180, used in its Atlas V vehicle for military space launch under the Air Force’s Evolved Expendable Launch Vehicle (EELV) program. The Russian-made RD-180 has become a source of controversy following that country’s invasion of Ukraine.
“The RD-180 is a great engine, it’s a real workhorse, it’s reliable and it’s high performance,” Tory Bruno, ULA president, told reporters. “But this is a real opportunity to jump ... into the 21st century with modern technology so we can achieve more performance at a lower cost.”
Blue Origin has been a passion project for Jeff Bezos, best known as the founder of Amazon.com, and more recently as the new owner of the Washington Post.
Its prime facility is located just outside of Seattle — close to a number of facilities operated by Boeing, which owns half of ULA in a partnership with Lockheed Martin.
Bruno, who replaced long-time ULA head Michael Gass in August, heaped praise on Bezos as a true American success story.
“I just have to say how honored I am to sit up here with Jeff Bezos, one of our country’s truly great innovators and entrepreneurs, a man who has really changed how things work,” Bruno said.
It was hard not to miss the fact ULA now has its own silicon valley superstar on board to help counter the popularity of Elon Musk, the PayPal and Tesla Motors inventor whose SpaceX launch company has proven a thorn in ULA’s side.
That will be particularly helpful when dealing with Congress, which has clearly taken a shine to SpaceX as an alternative to the legacy provider of military launch. But while Bruno said the team was already holding meetings with members of Congress on its new venture, he insisted the decision was driven by the technology Blue Origin could bring to the table.
Bezos, for his part, referred to ULA’s decision to use its technology as a “huge endorsement from a very successful space launch company.”
The engine in question is the Blue Engine 4 (BE-4), which Bezos said could provide 555,000 pounds of thrust, operating with liquefied natural gas.
In the future, the engine also has the potential to be reusable, although that won’t occur for EELV purposes, Bezos told reporters.
Both men stressed that the Blue Origin team has been working on the engine for three years, which should reduce needed development time. Analysts have estimated that developing a new engine from scratch could take anywhere from five to seven years and cost $1 billion.
“By partnering with [Blue Origin], we have the opportunity to really cut that cycle in half,” Bruno said. “That means that in about four years from now we will be in a position to start flying rockets with this engine technology.”
ULA is making a “significant” investment in Blue Origin, Bezos said, but declined to say how much money the launch company was funneling to its new partner.
The engines will be adapted for the Atlas V and Delta IV, ULA’s existing launch vehicles. That will require some re-engineering on the vehicles to adjust for the differences in size and weight of the new stage-one rocket engines. ULA engineers are studying that issue and expect to make their decisions public by the end of the year, Bruno said.
Bruno confirmed that the relationship came out of a series of study contracts ULA announced in June.
The ULA event was held at the National Press Club in downtown Washington. As Bezos and Bruno finished speaking, the Air Force’s head of Space Command, Gen. John Hyten, discussed the announcement with reporters at the Air Force Association’s Air and Space conference, being held just outside the city.
Hyten said he was “excited” about the partnership, according to news reports. Both Bezos and Bruno said they had contacted the Air Force and received positive feedback about the new agreement.
Quelle: defensenews
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United Launch Alliance and Blue Origin Announce Partnership To Develop New American Rocket Engine

Centennial, Colo. and Kent, Wash. – Sept. 17, 2014 – United Launch Alliance (ULA), the nation’s premier space launch company, and Blue Origin, LLC, a privately-funded aerospace company owned by Amazon.com founder Jeff Bezos, announced today that they have entered into an agreement to jointly fund development of the new BE-4 rocket engine by Blue Origin. This new collaboration will allow ULA to maintain the heritage, success and reliability of its rocket families – Atlas and Delta – while addressing the long-term need for a new domestic engine.
“This agreement ensures ULA will remain the most cost-efficient, innovative and reliable company launching the nation’s most important national security, civil, human and commercial missions,” said Tory Bruno, president and chief executive officer of ULA. “Blue Origin has demonstrated its ability to develop high-performance rocket engines and we are excited to bring together the best minds in engineering, supply chain management and commercial business practices to create an all-new affordable, reliable, American rocket engine that will create endless possibilities for the future of space launch.”
"ULA has put a satellite into orbit almost every month for the past eight years – they’re the most reliable launch provider in history and their record of success is astonishing,” said Jeff Bezos, founder of Blue Origin. “The team at Blue Origin is methodically developing technologies to enable human access to space at dramatically lower cost and increased reliability, and the BE-4 is a big step forward. With the new ULA partnership, we’re accelerating commercial development of the next great US-made rocket engine.”
The ULA/Blue Origin agreement allows for a four-year development process with full-scale testing in 2016 and first flight in 2019. The BE-4 will be available for use by ULA and Blue Origin for both companies’ next generation launch systems.
The BE-4 is a liquid oxygen, liquefied natural gas (LNG) rocket engine that delivers 550,000-lbf of thrust at sea level. Two BE-4s will power each ULA booster, providing 1,100,000-lbf thrust at liftoff. ULA is investing in the engineering and development of the BE-4 to enable availability for national security, civil, human and commercial missions. Development of the BE-4 engine has been underway for three years and testing of BE-4 components is ongoing at Blue Origin’s test facilities in West Texas. Blue Origin recently commissioned a new large test facility for the BE-4 to support full engine testing.
About United Launch Alliance
With more than a century of combined heritage, United Launch Alliance is the nation’s most experienced and reliable launch service provider. ULA has successfully delivered more than 80 satellites to orbit that provide critical capabilities for troops in the field, aid meteorologists in tracking severe weather, enable personal device-based GPS navigation and unlock the mysteries of our solar system. Bringing rocket science down to Earth.
Quelle: Blue Origin

Tags: Raumfahrt 

2319 Views

Donnerstag, 18. September 2014 - 21:33 Uhr

Raumfahrt - Die Amateur-Raketenwissenschaftler von Philadelphia Raketen Association (PARA)

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A small group of amateur rocket scientists keep their fizzling hobby alive

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Jim Hansen has been in and out of rocketry for 50 years.
First you see the signs, yellow with bold, black lettering: "Caution. Rocket launch in progress."
They're posted at the far end of a black gravel driveway that leads past a farmhouse and scattered harvesting equipment, and right up to a red dirt road that opens to a clearing between two cornfields.
A row of cars, like an honor guard standing at attention, is parked behind a line of white flags demarcating the safe zone. Down the field are 15 launch pads, grouped into sections denoted by letters from A to D, set up at varying distances. Rockets with engines less than an inch around will launch from the six A pads. Pads B and C are for rockets with larger engines. But today's crowd of about 12 is most interested in the two D pads 50 yards down.
It's shortly after 11 a.m. on an overcast, but not rainy, Sunday in August, an ideal day for firing model rockets into the sky. Wind, at least what can be felt from the ground, is minimal. The cloud ceiling is very high, which makes Ken Derstine's 5-foot rocket, named This End Up, the perfect one to let loose.
Inside the rocket's base, near the fins, is a reloadable metal casing, 6 inches long and packed with ammonium perchlorate, a rubbery, granular, solid rocket propellant. This is the type of stuff used in military-grade rockets, albeit in larger quantities and with other substances.
At a nearby launch station, someone checks to make sure that the electric current running through the wires from the operator's table to the D pads is unbroken. When the current makes it to the D pads, it will transfer to an aluminum wire coated in a pyrogenic substance that will ignite the propellant. Countdown begins: 5, 4, 3, 2, 1.
In less than a second, the rocket lifts from the pad at more than 200 miles an hour with a noise that sounds like a cross between a whoosh and a thawed steak hitting hot oil inside a frying pan. A swirl of fluorescent green and orange knifes through the sky with a smoky black trail chasing behind. Craned necks track its progress.
After about nine seconds, the rocket burns through the last of its fuel and, at 1,040 feet, hits apogee, the moment when the forces of gravity begin to pull it back to the Earth's surface. A distant pop registers as the rocket breaks apart at the middle — all part of the plan.
The first parachute, a thin piece of nylon called a drogue, deploys; its purpose is to prevent high-altitude winds from pulling the rocket into the remote reaches of either of the two cornfields boxing in its descent.
A programmable altimeter powered by a 9-volt battery inside the rocket tracks its altitude as it falls, and at 500 feet, the nose cone breaks away. In a process known as dual-deploy, a second parachute flows from the top, slowing the rocket's descent even more until it recedes behind the stalks of corn on its way to a soft, and recoverable, landing.
Barry McGarvey, a man with a shaved head wearing a yellow reflective vest — the person attending the launch station, and therefore responsible for pushing the buttons that send rockets skyward — gives the all-clear, and Derstine begins his walk through the damp, calf-high grass and into the cornfield to find his rocket.
Another one down — another 50 to go. Welcome to launch day with the Philadelphia Area Rocketry Association (PARA).
Like the faithful on pilgrimage, members of PARA have been returning to this Bucks County farm once a month since 1990. Located in Ottsville, about an hour north of Philadelphia, the field, which PARA rents from farmer Jim Hallowell, is a refuge to this band of rocketry geeks. Instead of dodging confrontational neighbors in parks near their homes or packing up their launch stands quickly when a baseball team shows up to reclaim the diamond, they get four hours the first Sunday of every month, save for any forces of nature that put a damper on a hobby that requires sparks, flames and dry black powder.
Membership in the group, while never a major concern, has waned to just 16 this year. Now it's on McGarvey — a man who builds his own rockets and is certified to fire off ones boosted by engines as thick as Italian salami — to keep the tradition alive as PARA enters its 25th year.
"We'll fly any month of the year, as long as conditions are OK," says McGarvey, 47, a Northeast Philadelphia resident and PARA member for the last five years.
Discovering this local rocketry club took McGarvey some time, however. Growing up near Franklin Mills, he and his brother would shoot off model rockets behind their house. At age 21, McGarvey bought his first model rocket, and as his interest grew he resorted to finding any open, flat area to fire them, a strategy that often led him to unorthodox launch sites — considering he and his wife were living near Keystone Racetrack (what is now Parx Casino).
"I'd go over to the parking lot and fly it," he says. "Didn't have anybody's permission to do it. I did that for a good 15 years before I found [PARA]. I didn't even know these types of things existed."
Getting the word out about the group is part of McGarvey's challenge now. For the last two years he has served as president of PARA, a position he assumed when the last president wanted to step down.
"I said this is a good thing; we can't just let it die," he says.
PARA members are a tinkering subculture. They arrive at the Sunday launches with toolboxes and plastic crates of gear crammed into car trunks: pliers, wire strippers, screwdrivers, pencils, igniters. Some carry extra grease to make dysfunctional rocket parts easier to pry off. McGarvey brings a tub of nylon parachutes this August afternoon, as well as additional shock cords made of flame-retardant Nomex and Kevlar. One member carries an entire case of "dog bark," slang for a protective insulating material placed inside the hollow body of a rocket between the engine and the parachute.
They fawn over rockets the same way car collectors go weak in the knees for '68 Mustangs. Grab any one of them, and they all say something similar: "I've been launching model rockets since I was a boy."
Many of them today build their own rockets from cardboard and fiberglass tubes in basement and home workshops. The rockets range from barely a few inches to more than 6 feet tall. The size and location of the PARA launch field limit what rockets can be launched, restrictions imposed by the Federal Aviation Administration.
A notice to airmen — a document warning airplane pilots of potential hazards along their flight routes — is required for every PARA launch. McGarvey requests one from the FAA the Saturday before each launch. Most members stick to launching model rockets, the hobby variety that are sold in prepackaged kits, weigh less than 3 pounds and have engines designated with letters from A to G. (Each step up the alphabet represents an engine capable of launching a rocket with twice the thrust as the preceding one.)
Those who are certified may launch rockets powered by engines represented by letters G to O, which are used in high-powered rocketry. But the maximum allowed at the PARA field are G80 engines
"You can't fly these in the neighborhood," says Derstine with a laugh as he prepares Red Dawn, a 71-inch-tall, high-powered rocket wrapped in fiberglass for extra strength. The fins are three-ply wood, tougher than balsa. A 59-year-old mechanic from Sellersville,Derstine has been with the group for about eight years, and has the losses to show for it.
"I've got a couple hanging out in the woods back there, across the creek," he says, his index finger pointing to the far edge of the launch field, where the rows of corn trail off into a grove of trees. "As you come here, you learn. You make a mistake. You go too high. A lot of times, it's not windy here, but you get up too high — I got a couple hanging over there."
Chasing falling rockets is part of the PARA ritual. Even though prepackaged model rocket kits start at only $10, prices increase from there to $100 for larger rockets with bigger engines. One of Derstine's rockets hanging in the woods still holds a reloadable metal casing worth $70. And no member wants to lose a built-from-scratch rocket, for which he might have made measurements, cut fins and tubing and sourced sturdier wood and fiberglass. This End Up took Derstine several weekends to assemble, he says.
Though a certain amount of unpredictability hangs over the monthly launches — PARA members, in addition to paying $25 in annual dues and a launch-day fee of $5, must sign a liability waiver acknowledging that "known risks of participating in rocket launches include ... bodily injury and death" — there's a greater chance of damage to a haphazardly constructed rocket.
Chris LaBelle, a landscaper and part-time chemistry professor who brings his 13-year-old son, William, to the launches, sees his 8-inch rocket explode into three parts not long after it clears the launch pad.
"Keep an eye on section three!" he calls out, hoping for help in finding it.
John McConville, a 28-year-old mechanical engineer from Allentown who has been attending PARA launches for the last year and a half, experienced a different problem with his foot-long orange rocket dubbed Wizard. Takeoff was a cinch, and the Wizard reached apogee at the height of its flight as it was meant to. But as the nose cone on McConville's rocket popped off to release the parachute, it detached from the rocket body along with the parachute.
"Separation!" everyone cheers — followed by a wisecrack about separation anxiety — and McConville takes off running toward the cornfield with eyes trained skyward. Without the help of a brightly colored chute, it's difficult to place a falling rocket, but a thud is audible from about 30 feet away, and McConville returns from navigating the maze of corn with Wizard in hand.
The Philadelphia rocketry group is one of 125 similar groups scattered across the U.S. and affiliated with the National Association of Rocketry (NAR). The founders of PARA, none of whom are still group members today, were all local members of the NAR. As a nonprofit scientific organization, the NAR promotes both the hobby of sport rocketry (as model rocketry is known to enthusiasts) and youth education to swell the ranks of its 5,800 members nationwide.
It's also the NAR that bestows certifications on adult rocketry hobbyists like McGarvey and Derstine.
Perhaps it's no surprise that a group that has been so influential to the growth of model rocketry in the U.S. formed in 1957. That was the year the Soviet Union launched the first satellite into orbit, the opening shot in a space race that would see the founding of the Gemini and Apollo space programs as well as an American president who told the country, "We choose to go to the moon." It was the U.S. that took both the small steps and the giant leap into space travel and exploration. Rocketry, it might be argued, is as American as baseball and apple pie.
But sustaining interest appears to be a game of hit-or-miss.
"People seem to come and go out of rocketry," says McGarvey. "There's a core group of us that's seemed to stay the same. For some reason I guess people move on or their life becomes too busy."
Like McGarvey, Derstine first began launching rockets as a kid. But as he got older, and had his own children, he drifted from hobby rocketry. It wasn't until his three sons graduated from college that he found time to take up model rocketry again.
Jim Hansen, a retired electrical engineer easily recognizable by the stud in his left earlobe, tells a similar story. "I started when there were no rocket kits. I had one book on rockets and was using powdered zinc and sulfur for fuel. I made my first gunpowder when I was in the sixth grade," he says proudly, a toothy grin forming under his trim gray mustache.
He's been "off and on" in model rocketry for more than 50 years, he says, taking what seems to be the requisite break after getting married. For the last eight years, though, Hansen has been a steady presence in PARA, as both a past president and an active participant at the monthly launches. (He's the one who brought the case of dog bark.) At 71, Hansen's the elder statesman of the group. The biggest rocket he'll set off on this day is Minnie Magg, a 4.8-pound rocket that flies off the D pad.
"I was born on the Fourth of July. And that's 90 percent of the battle right there," he says. "I always enjoyed the fireworks, and rockets were just a natural progression."
Occasionally PARA will attempt to attract newer, and younger, members. On Oct. 5, nine cadets from the Northeast Philadelphia Composite Squadron 104 of the Civil Air Patrol will head to Ottsville to launch rockets that McGarvey helped them assemble.
While construction of the rockets is a worthwhile challenge, the real joy surfaces on launch day.
When Big Bertha, a 2-foot, all-black rocket, comes off the launch pad and goes screaming 1,500 feet into the air, McGarvey quickly dons his sport shades, stretches his neck upward and then shouts, "I got it!" before tearing off running down the dirt road, parallel to the cornfield, so he can pinpoint the exact spot where it lands.
And in that moment — seeing a grown man break into a big smile before galloping after a rocket falling under chute — I'm reminded that my own path to this story mirrored the stories I've been asking strangers to tell me all afternoon.
I was an 8-year-old boy growing up in Chester County when my father bought my first model rocket. It was a kit that included several small engines sold by Estes, one of the more popular model rocket manufacturers. We assembled it together; it couldn't have been taller than a foot. He showed me where the fins attached to the rocket's base and at precisely what angle I should hold the bottle of Super Glue to make sure the nozzle wouldn't clog.
An aerospace engineer by training, he explained to me the purpose of the pinkish-red streamer we stuffed into the rocket body before pressing on the nose cone. On weekends he would drive us to Hibernia Park to launch it, making sure that I never got too close to the lit engine. I'd gawk at the sky waving my index finger around, never quite sure exactly where my rocket had flown. When the streamer shot out of the nose cone I'd run at him to get his attention, and then he'd tell me to run after it. One day, we lost it in the trees, and I cried the entire way home. I loved that rocket, but I loved those afternoons with my dad even more.
As the hours ticked away that recent August Sunday, I thought more than once about searching for a local hobby store, buying my own rocket and chipping in my $5 at the next month's launch. I was envious. Here was a menagerie of proud geeks joining in on an activity that's overwhelmingly nostalgic — for all of us.
"You come out here and you just spend a day launching rockets. You're not bothering anybody. Nobody bothers you. You don't have to worry about anything," says McGarvey, almost breathlessly. "When that smell of the burnt rocket fuel mixes with the manure, I enjoy it, as weird as that sounds. I just love this stuff."
Quelle:CityPaper

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Donnerstag, 18. September 2014 - 10:00 Uhr

Astronomie - Grosses Schwarzes Loch in kleiner dichten M60-UCD1-Galaxy gefunden

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A team of researchers, including an MSU astronomer, has discovered a black hole at the center of an ultra-dense galaxy known as M60-UCD1. This Hubble Space Telescope image compares the size of that galaxy to the gigantic NGC 4647 galaxy.

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A team of researchers, including an astronomer from Michigan State University, has discovered a huge black hole at the center of an ultra-compact galaxy – the smallest galaxy known to contain one.
The galaxy, known as M60-UCD1, was discovered last year by a team led by Jay Strader, MSU assistant professor of physics and astronomy. Strader was a member of the team that found the black hole.
The findings are detailed in the recent edition of the journal Nature.
The finding suggests that other ultra-compact galaxies also may contain massive black holes. And that those galaxies may be the stripped remnants of larger galaxies that were torn apart during collisions with other galaxies.
There has been much debate whether ultra-compact dwarf galaxies are born as jam-packed star clusters or if they are galaxies that get smaller because they have stars ripped away from them. The discovery of this black hole, combined with the high galaxy mass and sun-like levels of elements found in the stars, favor the latter idea, Strader said.
The supermassive black hole found at the center of this galaxy is estimated to have a mass of 21 million suns. By comparison, the mass of the black hole found at the center of our Milky Way galaxy is only about 4 million suns.
The other interesting aspect of this finding, Strader said, is that it suggests supermassive black holes are more common in less-massive galaxies than previously thought.
"This means that the ‘seeds’ of supermassive black holes are more likely to be something that occurred commonly in the early universe," he said.
However, it does continue to be a matter of debate as to whether these black holes could instead have come about as a result of unusual "seeds," such as "super" stars that collapse directly to massive black holes, or runaway stellar collisions that occurred in the core of a dense star cluster.
The research was funded by the National Science Foundation, the German Research Foundation and the Gemini Telescope partnership, which includes the NSF and scientific agencies in Canada, Chile, Australia, Brazil and Argentina.
Quelle: Michigan State University

Tags: Astronomie 

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Mittwoch, 17. September 2014 - 19:30 Uhr

Astronomie - Visualisierung der vierten Dimension bei Asteroiden

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One of the largest treasure troves of astronomical data comes from the Sloan Digital Sky Survey (SDSS), an ongoing scan of the firmament that began 15 years ago. Its catalogue covers 35 percent of the sky and contains multicolor OBSERVATIONSof hundreds of millions of distinct galaxies, stars and quasars. If a person were to attempt to individually inspect each of these objects at a rate of one per second through the workday, it would be a full-time job lasting over 60 years!
Fortunately, such individual inspection is not how astronomers work. Instead, we use various specialized algorithms to automatically sift through and categorize this vast data set and dream up novel visualization schemes to make clear in a glance the relationships between thousands or millions of individual objects.
One of my favorite examples of this type of visualization involves a subset of the above data, the SDSS Moving Object Catalog, which my colleague Zeljko Ivezic has been instrumental in producing and collating. This catalogue contains detailed data on nearly half a million small asteroids orbiting our sun, allowing us not only to track the orbital path of individual asteroids but also to gain insight into the chemical composition and formation history of individual objects and THE SOLAR SYSTEM as a whole.
The SDSS data gives us much more than just the orbital dynamics. Multiband imaging gives us detailed measurements of the color of reflected sunlight off each of these asteroids. Just as on Earth our eyes can distinguish white quartz from dark basalt based on how they each reflect sunlight, the SDSS TELESCOPE can distinguish among different chemical compositions of asteroids based on how their surfaces reflect sunlight.
We can summarize this chemical information with two “color” measurements: color in the OPTICAL range and color in the near-infrared range. Combining this with the semimajor axis (a measure of the size of the orbit around the sun) and the inclination (a measure of how “tilted” the orbit is compared with Earth’s orbital plane) gives us a four-dimensional data set: four properties of each asteroid that contain information about its orbit and chemical composition.
Visualizing the fourth dimension 
With this four-dimensional data set decided, we can now think about how to best visualize it. One-dimensional data fits on a number-line; two-dimensional data can be plotted on a FLAT page or screen; three-dimensional data can be conceived as a 3-D plot, perhaps rotating on a computer screen; but how do you effectively plot four-dimensional data?
We can start simple, by splitting the data into chemical indicators on one hand and orbital indicators on the other:
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This visualization is full of information. The left PANEL is known as a color–color diagram and distinguishes between broad classes of asteroid chemistries. The left-most clump in this panel is primarily carbonaceous (C-type) asteroids whereas the right-most clump is primarily silicaceous (S-type) asteroids. The faint downward extension of the right-most clump is V-type asteroids, known to be associated with the asteroid Vesta.
The right panel showing the orbital characteristics offers even more insight. Immediately we see that there is some intriguing structure to the data: clumps and clusters as well as specific regions that are devoid of any asteroids at all. These clumps are known as asteroid families, and the vertical voids near 2.5 astronomical units (AU) and 2.8 AU are areas of orbital resonance with Jupiter: In this particular region of THE SOLAR SYSTEM, these resonance effects quickly kick any asteroids out of their orbits. (An astronomical unit is the mean Earth–sun distance, or about 149.6 million kilometers.)
These are all interesting insights, but what we’d really like is to see INTUITIVELYhow the chemistry reflected in the left panel is related to the orbital dynamics reflected in the right panel. Such a four-dimensional relationship is very difficult to capture.
Plotting all pairs of dimensions

One common way to visualize high-dimensional data is to use a grid of multiple two-dimensional plots. In this way we can plot each pair of features against one another and look at the correlations. Of course, the two PANELS from above are just a subset of the six distinct plots (each with a mirror-image) created by this method:
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This plot conveys a lot of information, and there are some intriguing pieces. For example, in the PANEL comparing near-infrared color to orbital inclination (top row, second from the left) we see a distinct clump of data: These are points that are clustered both in color and inclination. Further investigation shows this clump reflects the Vesta family, a chemically similar group of asteroids that also shares the same orbital inclination. We’ll return to these below.
Colors as added dimensions 
Another common high-dimensional visualization technique is to treat color as an added dimension. This way a standard two-dimensional plot can reflect three-dimensions of information. Let’s try visualizing the four dimensions in this way: We’ll do two versions of the orbital inclination plot, using a different color scale in each plot:
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In the left plot the colors of the points correspond to the OPTICAL color whereas in the right plot the colors correspond to the near-infrared color. With this enhancement, we’re really getting somewhere: The left panel makes clear that the clumps of asteroids in orbital space are generally grouped according to their optical colors—that is, their position on the carbonaceous–silicaceous spectrum. The right plot shows the Vesta group that we pointed out above—the group of asteroids near 2.4 AU with a blue-infrared color.
Multicolor plot
Let’s put these all together. Rather than using two separate color scales to identify these asteroid groups, we can define a SINGLE two-dimensional color scale reflecting the asteroid chemistry and use these colors when plotting the same points in orbital space. The result is a plot very similar to the one that appeared in Parker et al, 2008, where this work was first reported:
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This final plot offers a full, INTUITIVE view of the relationships between the four measured asteroid characteristics. From this visualization, it becomes clear that asteroid chemistry (reflected in the color of the individual points defined by the left panel) is strongly related to the orbital distribution of asteroids (reflected in the clumping of asteroid families in the right panel). What this shows is that families of asteroids not only orbit near one another in space, but also have largely the same chemical composition!

This OBSERVATION lends evidence to the theory that asteroid families are formed by collisions of larger bodies. At some time in the past, two larger asteroids likely collided, shattering into hundreds or thousands of smaller bodies. Because these smaller bodies each came from the same source, they will be chemically similar and continue to orbit in the same region for several hundred million years.

As the volume and complexity of data GROW, novel visualization techniques like this are an important part of mining large data sets in search of such insights.

Quelle: Scientific American


Tags: Astronomie 

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