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Sonntag, 23. Dezember 2012 - 23:07 Uhr

Raumfahrt - Sonnensonde SOHO nimmt Erde auf

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The STEREO Behind spacecraft has now moved far enough in its orbit for Earth to enter the HI1-B field-of-view. Earth has been visible in the HI2 telescopes since launch, but this is the first time it's been visible in either of the HI1 telescopes, which image areas closer to the Sun. This is happening because the STEREO spacecraft are moving closer to the points in their orbits at which they will be directly opposite Earth on the other side of the Sun.

In the above image, Earth is the object at the center right edge. The bright object near the upper-right corner is the bright star Pollux (β Gem; sorry for the incorrect label). Soon Earth will be visible in STEREO Ahead's HI1 and eventually in the coronagraphs. In 2015 the Earth will pass behind the Sunfrom the point of view of the two spacecraft.

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Quelle: NASA


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Sonntag, 23. Dezember 2012 - 22:49 Uhr

Luftfahrt - DLR untersucht maritime Flugmissionen mit unbemannten Luftfahrzeugsystemen

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Für die Küstenwache und Katastrophenhilfe ist es eine große Herausforderung, den Überblick über weitläufige Meeresgebiete zu gewährleisten. Zukünftig sollen unbemannte Luftfahrzeuge dazu einen entscheidenden Beitrag leisten. Im Dezember 2012 simulierte das Deutsche Zentrum für Luft- und Raumfahrt (DLR) unbemannte Erkundungsflüge über dem Mittelmeer. Die virtuellen Testläufe zeigten ein funktionierendes Zusammenspiel mit dem regulären Flugverkehr. Sie bereiten erste ferngeführte Erprobungsflüge rund um die südspanische Stadt Murcia im Sommer 2013 vor.

"Echtzeitaufnahmen aus der Luft sind ein wesentlicher Baustein zur Erstellung maritimer Lagebilder", sagt Dr. Dennis Göge, DLR-Programmkoordinator Sicherheitsforschung. "Heute werden Luftaufnahmen immer noch fast ausschließlich mit bemannten Luftfahrzeugen erflogen. Wir arbeiten gemeinsam mit unseren Partnern im Projekt Desire daran, dass zukünftig auch unbemannte Luftfahrzeuge  auf offener See zum Einsatz kommen können. Damit leisten wir einen Beitrag zur Erhöhung der maritimen Sicherheit." Desire (Demonstration of Satellites Enabling the Insertion of Remotely Piloted Aircraft Systems in Europe) ist ein Projekt der ESA mit dem Ziel, die satellitengestützte Führung unbemannter Luftfahrzeuge in Küstennähe und über dem Meer zu erproben.

Detailliertes Monitoring der Meere 

"Die Simulation zeigt, dass sich unbemannte Luftfahrzeuge in den zivilen kontrollierten Flugverkehr einfügen können", sagt der beim Bundesministerium des  Innern für Technik und Logistik der Bundespolizei zuständige Referatsleiter Achim Friedl. Er informierte sich vor Ort am DLR-Standort Braunschweig über die Simulationskampagne. "Für die Aufgabenwahrnehmung der Bundespolizei auf der Nord- und Ostsee könnte die Verwendung von unbemannten Luftfahrzeugen eine Ergänzung des heutigen Einsatzes von Patrouillenbooten und Hubschraubern sein." Ein detailliertes Monitoring der Meere ist wichtig, um Hilfe rechtzeitig an den richtigen Ort zu bringen. Beispielsweise sind Schiffbrüchige aus der Luft schneller auffindbar. Und es profitiert der Meeresschutz, wenn etwa illegale Tankspülungen aufgedeckt werden.

Für Aufnahmen mit unbemannten Luftfahrzeugen  über dem Meer ist satellitengestützte Kommunikation unverzichtbar. Diese Luftfahrzeuge mit eingebauter Sensorik haben gegenüber  Beobachtungssatelliten den Vorteil, dass sie kontinuierlich aktuelle Detailinformationen einer Region liefern können. Da sie über dem Meer außerhalb der direkten Sichtweite operieren,  benötigen sie eine Datenverbindung  per Satellit zum Piloten in der Bodenkontrollstation. So wird eine zuverlässige Kommunikation und Steuerung ermöglicht.

Virtuelle Erprobung des Erstfluges

Das DLR hat mit der Simulationskampagne den satellitengestützten Erstflug eines unbemannten Luftfahrzeuges im südspanischen Murcia vorbereitet. Dabei nutzten die Wissenschaftler ihre breite Kompetenz in der virtuellen Analyse des europäischen Luftverkehrs. "Wir müssen sichergehen, dass es bei der Erprobung der ferngeführten Luftfahrzeuge zu keiner Beeinträchtigung des regulären Flugverkehrs kommt", sagt Dr. Dirk-Roger Schmitt vom DLR-Institut für Flugführung. "Das Zusammenspiel mit den Fluglotsen im Tower und den Piloten am Boden muss funktionieren. Im virtuellen Testlauf konnten wir das zeigen." Das Projektkonsortium muss den spanischen Luftfahrtbehörden vorab einen einwandfreien Flugverlauf für die Genehmigung des Erstflugs nachweisen. Die Simulationskampagne dient dafür als Grundlage.

Fluglotsen und ein Pilot für unbemannte Luftfahrzeugsysteme waren für die Kampagne im Validierungszentrum Luftverkehr des Instituts für Flugführung in Braunschweig vor Ort. Dort waren sowohl Fluglotsenarbeitsplätze, die Bodenstation für das Luftfahrzeug sowie die Arbeitsplätze für die Piloten der anderen Flugzeuge, die in der Simulation den Luftraum mit dem unbemannten Luftfahrzeug teilen,  eingerichtet. Die Akteure wickelten die ferngeführten Flüge wie in der Realität ab. Sie kommunizierten über eine Sprechfunkverbindung, während das Fluggerät per simuliertem Datenlink mit der Bodenstation verbunden war. Das Luftfahrzeug startete beispielsweise virtuell von einer Startbahn des Flughafens Murcia San Javier, flog dann nach einem vorher festgelegten Flugplan Richtung Osten auf das Mittelmeer hinaus, um Schiffbrüchige aufzufinden und kehrte schließlich - ein paar Mausklicks später - per automatischer Landung zurück. Die virtuellen Flüge wurden unter verschiedenen Verkehrs-, Wetter und Kommunikationsbedingungen geflogen. Beispielsweise untersuchten die Wissenschaftler, wie sich die Zeitverzögerung in der Signalübertragung per Satellit auf den Flug im kontrollierten Luftraum auswirkt.  In einem anderen Fall konnten die Forscher Verfahren, die bei Unterbrechung der Funkverbindung  angewendet werden, erproben.

"Die Ergebnisse der jetzigen virtuellen und späteren realen Flugversuche in Murcia nutzen wir ebenso für das Projekt "F&E für die Maritime Sicherheit und entsprechende Echtzeitdienste", dessen Förderung in diesem Jahr vom Haushaltsausschuss des Deutschen Bundestags beschlossen wurde", ergänzt Dr. Dennis Göge. Im Rahmen des Projekts forscht das DLR für einen verbesserten Küsten- und Meeresschutz sowie einen sicheren Schiffsverkehr.

ESA-Projekt Desire

Desire ist ein Projekt der ESA im Rahmen des ARTES-Programmes. Hauptauftragnehmer  des Forschungsprojektes ist die spanische Firma Indra SA. Die experimentelle Simulation wurde als Unterauftrag an  AT-One EWIV vergeben. AT-One EWIV ist eine gemeinsame Unternehmung des DLR und seines Partners NLR (National Aerospace Laboratory of the Netherlands). Beide  Forschungseinrichtungen bündeln in der Allianz AT-One ihre Kompetenzen im Bereich Luftverkehrsmanagement.

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Quelle: DLR


3430 Views

Sonntag, 23. Dezember 2012 - 15:00 Uhr

Mars-Curiosity-Chroniken - Curiosity-News Sol 132+133

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This image was taken by Mars Hand Lens Imager (MAHLI) onboard NASA's Mars rover Curiosity on Sol 132 (2012-12-19 19:59:43 UTC) .

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This image was taken by Mars Hand Lens Imager (MAHLI) onboard NASA's Mars rover Curiosity on Sol 132 (2012-12-19 20:04:38 UTC) .

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This image was taken by Navcam: Right A (NAV_RIGHT_A) onboard NASA's Mars rover Curiosity on Sol 132 (2012-12-19 17:43:21 UTC) .

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This image was taken by Navcam: Left A (NAV_LEFT_A) onboard NASA's Mars rover Curiosity on Sol 132 (2012-12-19 17:52:33 UTC) .

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This image was taken by Front Hazcam: Left A (FHAZ_LEFT_A) onboard NASA's Mars rover Curiosity on Sol 132 (2012-12-19 17:59:19 UTC) .

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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 133 (2012-12-20 18:12:39 UTC) .

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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 133 (2012-12-20 18:15:16 UTC) .

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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 133 (2012-12-20 18:16:33 UTC) .

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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 133 (2012-12-20 18:20:58 UTC) .

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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 133 (2012-12-20 18:23:08 UTC) .

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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 133 (2012-12-20 18:23:49 UTC) .

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This image was taken by ChemCam: Remote Micro-Imager (CHEMCAM_RMI) onboard NASA's Mars rover Curiosity on Sol 133 (2012-12-20 17:53:11 UTC) .

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This image was taken by Navcam: Right A (NAV_RIGHT_A) onboard NASA's Mars rover Curiosity on Sol 133 (2012-12-20 19:20:06 UTC) .

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This image was taken by Navcam: Right A (NAV_RIGHT_A) onboard NASA's Mars rover Curiosity on Sol 133 (2012-12-20 20:37:55 UTC) .

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This image was taken by Navcam: Right A (NAV_RIGHT_A) onboard NASA's Mars rover Curiosity on Sol 133 (2012-12-20 20:36:12 UTC) .

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This image was taken by Front Hazcam: Left A (FHAZ_LEFT_A) onboard NASA's Mars rover Curiosity on Sol 133 (2012-12-20 19:32:52 UTC) .

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Fotos: NASA


3372 Views

Sonntag, 23. Dezember 2012 - 13:00 Uhr

Astronomie - Seit seiner Einführung im Jahr 2001 hat die Wilkinson Microwave Anisotropy Probe (WMAP) Weltraummission unsere Sicht des Universums revolutioniert

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WMAP Team Releases Final Results, Based on Nine Years of Observations

 

Since its launch in 2001, the Wilkinson Microwave Anisotropy Probe (WMAP) space mission has revolutionized our view of the universe, establishing a cosmological model that explains a widely diverse collection of astronomical observations. Led by Johns Hopkins astrophysicist Charles L. Bennett, the WMAP science team has determined, to a high degree of accuracy and precision, not only the age of the universe, but also the density of atoms; the density of all other non-atomic matter; the epoch when the first stars started to shine; the “lumpiness” of the universe, and how that “lumpiness” depends on scale size.

In short, when used alone (with no other measurements), WMAP observations have made our knowledge of those six parameters above about 68,000 times more precise, thereby converting cosmology from a field of often wild speculation to a precision science.

Now, two years after the probe “retired,” Bennett and the WMAP science team are releasing its final results, based on a full nine years of observations.

“It is almost miraculous, says Bennett, Alumni Centennial Professor of Physics and Astronomy and Johns Hopkins Gilman Scholar at the Johns Hopkins University’s Krieger School of Arts and Sciences. “The universe encoded its autobiography in the microwave patterns we observe across the whole sky. When we decoded it, the universe revealed its history and contents. It is stunning to see everything fall into place.”

WMAP’s “baby picture of the universe” maps the afterglow of the hot, young universe at a time when it was only 375,000 years old, when it was a tiny fraction of its current age of 13.77 billion years. The patterns in this baby picture were used to limit what could have possibly happened earlier, and what happened in the billions of year since that early time. The (mis-named) “big bang” framework of cosmology, which posits that the young universe was hot and dense, and has been expanding and cooling ever since, is now solidly supported, according to WMAP.

WMAP observations also support an add-on to the big bang framework to account for the earliest moments of the universe. Called “inflation,” the theory says that the universe underwent a dramatic early period of expansion, growing by more than a trillion trillion-fold in less than a trillionth of a trillionth of a second. Tiny fluctuations were generated during this expansion that eventually grew to form galaxies.

Remarkably, WMAP’s precision measurement of the properties of the fluctuations has confirmed specific predictions of the simplest version of inflation:  the fluctuations follow a bell curve with the same properties across the sky, and there are equal numbers of hot and cold spots on the map. WMAP also confirms the  predictions that the amplitude of the variations in the density of the universe on big scales should be slightly larger than smaller scales, and that the universe should obey the rules of Euclidean geometry so the sum of the interior angles of a triangle add to 180 degrees.

Recently, Stephen Hawking commented in New Scientist that WMAP’s evidence for inflation was the most exciting development in physics during his career.

The universe comprises only 4.6 percent atoms. A much greater fraction, 24 percent of the universe, is a different kind of matter that has gravity but does not emit any light — called “dark matter”. The biggest fraction of the current composition of the universe, 71%, is a source of anti-gravity (sometimes called “dark energy”) that is driving an acceleration of the expansion of the universe.

“WMAP observations form the cornerstone of the standard model of cosmology, “says Gary F. Hinshaw of the University of British Columbia, who is part of the WMAP science team. “Other data are consistent and when combined we now know precise values for the history, composition, and geometry of the universe.”

WMAP has also provided the timing of epoch when the first stars began to shine, when the universe was about 400 million old.  The upcoming James Webb Space Telescope is specifically designed to study that period that has added its signature to the WMAP observations.

WMAP launched on June 30, 2001 and maneuvered to its observing station near the “second Lagrange point” of the Earth-Sun system, a million miles from Earth in the direction opposite the sun. From there, WMAP scanned the heavens, mapping out tiny temperature fluctuations across the full sky.  The first results were issued in February 2003, with major updates in 2005, 2007, 2009, 2011, and now this final release. The mission was selected by NASA in 1996, the result of an open competition held in 1995. It was confirmed for development in 1997 and was built and ready for launch only four years later, on-schedule and on-budget.

“The last word from WMAP marks the end of the beginning in our quest to understand the Universe,” comments fellow Johns Hopkins astrophysicist Adam G. Riess, whose discovery of dark energy led him to share the 2011 Nobel Prize in Physics. “WMAP has brought precision to cosmology and the Universe will never be the same.”

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Quelle:Johns Hopkins University


2957 Views

Samstag, 22. Dezember 2012 - 22:29 Uhr

Planet Erde - Schön das sie nicht unter ging...

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...und wir auf ihr leben können. AUFNAHMEN stammen von Beobachtungssatelliten LANDSAT-5

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Blick auf Myanmar

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Blick auf Griechenland

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Blick auf Erie-See

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Blick auf Mount Elgon

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Blick auf Eyre-See

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Quelle: NASA


3262 Views

Samstag, 22. Dezember 2012 - 15:01 Uhr

Raumfahrt - NASA testet Orion-Fallschirmsystem

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NASA Puts Orion Backup Parachutes to the Test
 

A mockup Orion capsule is poised to drop from a plane 25,000 feet above the U.S. Army Yuma Proving Ground in Arizona to test the parachute design for the spacecraft that will take humans farther than they’ve ever been before – and return them to Earth at greater speeds than ever before. Photo credit: NASA

Three 300-pound main parachutes gently lower a mockup Orion capsule to the ground during a test at the U.S. Army Yuma Proving Ground in Arizona on Dec. 20. Photo credit: NASA

A mockup Orion capsule touches down in the desert of the U.S. Army Yuma Proving Ground in Arizona with the help of its three 300-pound main parachutes, after being dropped from an airplane 25,000 feet up. The test verified that the parachute design for the spacecraft – which will take humans farther than they’ve ever been before and return them to Earth at greater speeds than ever before – will work in the event of one of the capsule’s two drogue parachutes malfunctions.Photo credit: NASA

NASA completed the latest in a series of parachute tests for its Orion spacecraft Thursday at the U.S. Army Yuma Proving Ground in southwestern Arizona, marking another step toward a first flight test in 2014. The test verified Orion can land safely even if one of its two drogue parachutes does not open during descent.

Orion will take humans farther into space than ever before, but one of the most challenging things the multipurpose vehicle will do is bring its crew home safely. Because it will return from greater distances, Orion will reenter the Earth's atmosphere at speeds of more than 20,000 mph. After re-entry, the parachutes are all that will lower the capsule carrying astronauts back to Earth.


"The mockup vehicle landed safely in the desert and everything went as planned," said Chris Johnson, a NASA project manager for Orion's parachute assembly system. "We designed the parachute system so nothing will go wrong, but plan and test as though something will so we can make sure Orion is the safest vehicle ever to take humans to space."

Orion uses five parachutes. Three are main parachutes measuring 116 feet wide and two are drogue parachutes measuring 23 feet wide. The 21,000-pound capsule needs only two main parachutes and one drogue. The extra two provide a backup in case one of the primary parachutes fails.

To verify Orion could land safely with only one drogue parachute, engineers dropped a spacecraft mockup from a plane 25,000 feet above the Arizona desert and simulated a failure of one of the drogues. About 30 seconds into the mockup's fall, the second drogue parachute opened and slowed the mockup down enough for the three main parachutes to take over the descent.

The next Orion parachute test is scheduled for February and will simulate a failure of one of the three main parachutes.

In 2014, an uncrewed Orion spacecraft will launch from Cape Canaveral Air Force Station in Florida on Exploration Flight Test-1. The spacecraft will travel 3,600 miles above Earth's surface. This is 15 times farther than the International Space Station's orbit and farther than any spacecraft designed to carry humans has gone in more than 40 years. The main flight objective is to test Orion's heat shield performance at speeds generated during a return from deep space.

Quelle: NASA


442 Views

Samstag, 22. Dezember 2012 - 14:27 Uhr

Astronomie - Deutschland beteiligt sich bei SKA

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Germany joins the SKA Organisation

 

Ten countries now involved in the pre-construction phase of the world’s largest telescope

20 December 2012, Manchester, UK – The Board of Directors of the Square Kilometre Array (SKA) Organisation has approved Germany, represented by the Federal Ministry of Education and Research (BMBF), as the tenth member of the organisation to participate in the detailed design of the SKA telescope.

The SKA will be the largest and most sensitive radio telescope ever built. It will enable astronomers to glimpse the formation and evolution of the very first stars and galaxies after the Big Bang, investigate the nature of gravity, and possibly even discover life beyond Earth.

Professor John Womersley, chair of the board of the SKA Organisation, welcomed Germany’s membership. “Germany has an excellent track record not only in radio astronomy but also in the management and delivery of science megaprojects and associated engineering. This expertise will be of great benefit to the SKA project as we move towards the construction phase of this inspirational telescope”, he said.

Dr Beatrix Vierkorn-Rudolph, Deputy Director General, Federal Ministry of Education and Research and Professor Michael Kramer, Director of Max-Planck-Institut für Radioastronomie, an institute of the Max-Planck-Gesellschaft (MPG), have been appointed to represent Germany on the SKA Board of Directors. The German contribution to the SKA Organisation amounts to 1 million Euro and is financed 50% each by BMBF and MPG.

“We live in an exciting time for science and the unprecedented scale of the multi-national SKA project ensures that we will continue to be able to push the boundaries of physics and astronomy. The SKA genuinely has the potential to completely transform our understanding of the universe as we know it today”, says Professor Kramer.

Germany joins the SKA Organisation at the end of what has been an exciting first year for the newly formed organisation. In May 2012 the members of the SKA Organisation agreed on a dual site for the SKA to maximise on investments already made at the candidate sites in Australia and South Africa. Both sites offer exceptionally radio quiet environments for detecting very faint radio waves from the early universe and many thousands of SKA receptors will soon be constructed across these two desert regions. In September Professor Philip Diamond was appointed as the first permanent Director General of the SKA Organisation and in November staff moved into the new purpose-built SKA headquarters at Jodrell Bank Observatory near Manchester in the UK.

As a member of the SKA Organisation, Germany has voting rights and is eligible to appoint two representatives to the Board of Directors. The SKA Board of Directors has the authority to appoint senior staff, decide budgets, admit new project partners to the organisation and direct the work of the global work package consortia in the SKA pre-construction phase.

Germany joins the existing members of the SKA Organisation: Australia, Canada, China, Italy, the Netherlands, New Zealand, South Africa, Sweden and the United Kingdom. India is an associate member.

About the SKA

The Square Kilometre Array will be the world’s largest and most sensitive radio telescope. The total collecting area will be approximately one square kilometre giving 50 times the sensitivity, and 10 000 times the survey speed, of the best current-day telescopes. The SKA will be built in Southern Africa and in Australia. Thousands of receptors will extend to distances of 3 000 km from the central regions. The SKA will address fundamental unanswered questions about our Universe including how the first stars and galaxies formed after the big bang, how dark energy is accelerating the expansion of the Universe, the role of magnetism in the cosmos, the nature of gravity, and the search for life beyond Earth. Construction of phase one of the SKA is scheduled to start in 2016. The SKA Organisation, with its headquarters at Jodrell Bank Observatory, near Manchester, UK, was established in December 2011 as a not-for-profit company in order to formalise relationships between the international partners and centralise the leadership of the project.

Members of the SKA Organisation as of December 2012:

  • Australia: Department of Innovation, Industry, Science and Research
  • Canada: National Research Council
  • China: National Astronomical Observatories, Chinese Academy of Sciences
  • Germany: Federal Ministry of Education and Research
  • Italy: National Institute for Astrophysics
  • Netherlands: Netherlands Organisation for Scientific Research
  • New Zealand: Ministry of Economic Development
  • Republic of South Africa: National Research Foundation
  • Sweden: Onsala Space Observatory
  • United Kingdom: Science and Technology Facilities Council

Associate member:

  • India: National Centre for Radio Astrophysics
  • Quelle: SKA

3436 Views

Samstag, 22. Dezember 2012 - 13:50 Uhr

Raumfahrt - NASA beginnt mit Mega-Raketen-Konstruktion

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This screen capture from a NASA animation shows the design of the new heavy-lift rocket, the Space Launch System (SLS). (NASA)  

HUNTSVILLE, Alabama -- NASA's Space Launch System (SLS),the new heavy-lift rocket system being created for a mission to Mars, passed a major technical review Thursday at Huntsville's Marshall Space Flight Center. NASA says the system is on track to meet its 2017 launch date, and contractor Boeing can now begin building the core stage.

The core stage preliminary design review (PDR) was held Thursday at NASA Marshall and included representatives from the agency and Boeing. Boeing's Exploration Launch Systems in Huntsville is the prime contractor for the core stage and its avionics. Marshall manages the SLS Program.

The review was to make sure the core design met requirements "within acceptable risk and fell within schedule and budget constraints,

"Passing a preliminary design review within 12 months of bringing Boeing on contract shows we are on track toward meeting a 2017 launch date," said Tony Lavoie, manager of the SLS stages at Marshall. "We can now allow those time-critical areas of design to move forward with initial fabrication and proceed toward the final design phase -- culminating in a critical design review in 2014 -- with confidence."

The review was to make sure the core stage design met the requirements of the launch system "within acceptable risk and fell within schedule and budget constraints," a NASA statement said. It did that. The core stage will be built at NASA's Michoud Assembly Facility in New Orleans.

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Michoud Assembly Facility in eastern New Orleans / NASA

Construction is ready to begin in eastern New Orleans on the major components of NASA's new mega-rocket, designed to transport astronauts to deep space.

The work is expected to bring hundreds of high-paying jobs to the Michoud Assembly Facility when construction on the program, called the Space Launch System, reaches its peak, starting next year and leveling off in 2015.

The heavy-lift rock's massive core stage will be built at Michoud, and the engines that will power the vehicle beyond low-Earth orbit and into deep space will be test-fired at the Stennis Space Center in Mississippi.

The Space Launch System is designed to transport astronauts to far-off destinations like asteroids and Mars over the next decade-and-a-half, an Obama administration goal. An unmanned test mission for the mega-rocket is slated for 2017.

The program's design team completed a major technical review of the core stage Thursday at NASA's Marshall Space Flight Center in Huntsville, Ala., the agency said in a statement Friday.


3575 Views

Samstag, 22. Dezember 2012 - 13:40 Uhr

Astronomie - Asteroid auf 0,2%-Erdkurs im Jahre 2040

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UH Observations Result in “All Clear” for Potential Asteroid Impact

University of Hawaii at Manoa astronomers made new observations of asteroid 2011 AG5 that show that this asteroid, previously thought to have a significant potential to threaten Earth, no longer poses a significant risk of impact, NASA announced today. The orbital uncertainties of the 140-meter-diameter near-Earth asteroid had previously allowed a 0.2 percent chance of collision in February 2040, leading to a call for more observations to better constrain the asteroid’s future course.

Answering the call, David Tholen, Richard Wainscoat and Marco Micheli of the UH Institute for Astronomy used the 8-meter Gemini North telescope on Mauna Kea, Hawaii, to find the small, very faint asteroid on October 20, 21 and 27, 2012.

An analysis of the new data conducted by NASA’s Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, California, shows that the risk of collision in 2040 has been eliminated. The updated trajectory of 2011 AG5 is not significantly different, but the new observations have reduced the orbit uncertainties by more than a factor of 60, meaning that Earth’s position in February 2040 no longer falls within the range of possible future paths for the asteroid. With the updated orbit, the asteroid will pass no closer than 890,000 km (550,000 miles, over twice the distance to the moon) in February 2040, the time of the prior potential collision.

This result was expected. Earlier in 2012, NASA’s NEO Program Office conducted a contingency deflection analysis for the 2040 potential impact of 2011 AG5. Among the findings was that any new observations either in 2012 or in 2013, when the object will be much easier to observe, had a 95 percent likelihood of eliminating the hazard posed by 2011 AG5. If the potential for impact had been confirmed the impact odds could have risen as high as 1 in 10, but the May 2012 study found that scenario to be unlikely. While the interest in 2011 AG5 has been reduced by the new results, the experience gained by studying this real-world deflection problem has demonstrated that NASA is well situated to detect and predict the trajectories of Earth-threatening asteroids.

In addition to the Gemini measurements, Tholen, Micheli, and Garrett Elliott obtained less conclusive observations in September and earlier in October with the UH 2.2-meter telescope, also on the summit of Mauna Kea. Tholen explained, “As it turns out, the asteroid is highly variable in brightness, which is probably why we were unable to make definitive observations on the smaller telescope.”  

The data are being published by the Minor Planet Center in Cambridge, Mass.

Quelle:University of Hawaii

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"All Clear" Given on Potential 2040 Impact of Asteroid 2011 AG5

NASA/JPL Near-Earth Object Program Office
December 21, 2012

NASA scientists have announced that new observations of 2011 AG5 show that this asteroid, once thought to have a worrisome potential to threaten Earth, no longer poses a significant risk of impact. The orbital uncertainties of the 140m diameter near-Earth asteroid had previously allowed a 0.2% chance of collision in Feb. 2040, leading to a call for more observations to better constrain the asteroid's future course.

Answering the call, University of Hawaii astronomers Dave Tholen, Richard Wainscoat and Marco Micheli used the Gemini 8-meter telescope at Mauna Kea, Hawaii to successfully recover and observe the small and very faint asteroid on October 20, 21 and 27, 2012. In addition to improving our knowledge of the orbit, the Gemini observations also suggest the asteroid varies in brightness as it rotates and therefore may be elongated. Gemini is managed by the Association of Universities for Research in Astronomy (AURA). In addition to the Gemini measurements, Tholen, Micheli and Garrett Elliott obtained less conclusive observations on October 9 & 10 with the University of Hawaii 2.2-meter telescope, also situated on the summit of Mauna Kea. After extensive astrometric analysis by the team in Hawaii, all observations were then sent to the International Astronomical Union's Minor Planet Center in Cambridge, Massachusetts.

An analysis of the new data conducted by NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, California, shows that the risk of collision in 2040 has been eliminated. The updated trajectory of 2011 AG5 is not significantly different, but the new observations have reduced the orbit uncertainties by more than a factor of 60, meaning that the Earth's position in February 2040 no longer falls within the range of possible future paths for the asteroid. With the updated orbit, the asteroid will pass no closer than 890,000 km (over twice the distance to the moon) in Feb. 2040, the epoch of the prior potential collision.

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The position data obtained for near-Earth asteroid 2011 AG5 in October 2012 was used to update its orbit and dramatically reduce its future orbital uncertainties in February 2040. In the first plot, the asteroid's possible positions in space (region of uncertainty) prior to the orbit improvement is an extremely lengthy arc that includes the position of the Earth. Hence an Earth collision could not be ruled out. However, the observational data in October 2012 allowed a sixty-fold improvement in the 2040 region of uncertainty and the second plot shows that this, now much smaller, arc no long includes the Earth. Hence an Earth impact by 2011 AG5 in February 2040 is no longer possible.

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Earlier in 2012, NASA's NEO Program Office conducted a contingency deflection analysis for the 2040 potential impact of 2011 AG5. Among the findings was that any new observations either in 2012, or in 2013 when the object will be much easier to observe, had a 95% likelihood of eliminating the hazard posed by 2011 AG5. If the potential for impact had been confirmed, the impact odds could have risen as high as 1 in 10, but the study released in May 2012 found that scenario to be unlikely. While the interest in 2011 AG5 has been reduced by the new results, the experience gained by studying this potential real-world deflection problem has demonstrated that NASA is well situated to predict the trajectories of Earth threatening asteroids.

Quelle: NASA


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Freitag, 21. Dezember 2012 - 15:15 Uhr

Raumfahrt - Sojus-TMA-07M im Anflug zur ISS

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NASA-TV LIVE-Frams von Andockmanöver von TMA-07M an ISS


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