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Sonntag, 29. Juli 2012 - 16:00 Uhr

Raumfahrt - Progress-M-15M erfolgreich an ISS angedockt

 

 

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A second attempt to re-dock the Russian Progress M-15M resupply spacecraft to the International Space Station (ISS) with the help of a new rendezvous system has been a success, a spokesman for the Russian Mission Control Center said on Sunday.

“The re-docking took place in a normal mode at the estimated time,” a Mission Control spokesman told RIA Novosti.

The unmanned space freighter, which had arrived at the ISS in April, undocked from the station early on Monday in order to perform a series of engineering tests during re-docking designed to verify the Kurs-NA automated rendezvous system.

The vehicle initially separated to a distance of about 100 miles from the station and held position for 24 hours before Tuesday’s failed attempt to re-dock with the space station due to an apparent failure in the Kurs-NA sensors.

The failure triggered a passive abort - a standard procedure that took the Progress spacecraft to a safe distance of about 1.8 miles below the space station.

 

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Sonntag, 29. Juli 2012 - 10:31 Uhr

Raumfahrt - 7 Tage-Countdown für Mars-Rover Curiosity

 

 

 

 

Course Maneuver Successful; MSL Begins Final Approach

  • Sun, 29 Jul 2012 08:02:20 AM GMT+0200

    Late Saturday night, NASA's Mars Science Laboratory spacecraft successfully fine-tuned its course to better zero in on its target entry point into the Martian atmosphere on landing day. Two brief thruster firings totaling about seven seconds altered the spacecraft's velocity slightly, by about one-fortieth of one mile per hour (one centimeter per second). This trajectory correction maneuver—the fourth since MSL's launch—adjusted the point at which Curiosity will enter the Martian atmosphere by about 13 miles (21 kilometers). On landing day, MSL can steer enough during its flight through the upper atmosphere to correct for a miss of the target entry point by a few miles and still land within its target ellipse. Mission engineers and managers rated the projected 13-mile miss big enough to warrant a correction maneuver. Telemetry and tracking data indicate the maneuver was successful. MSL will have two further opportunities for additional course corrections during the final 48 hours before landing, if needed.

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Samstag, 28. Juli 2012 - 22:30 Uhr

Raumfahrt - Japan´s HTV-3 nähert sich der ISS zum Andock-Manöver

 

 

KOUNOTORI3 Completes First Height Adjustment Maneuver
Last Updated: July 26, 2012
KOUNOTORI3 performed its first Height Adjustment Maneuver (HAM1) at 2:01 a.m., July 26, 2012.
Next height adjustment maneuver is scheduled to begin at 11:35 a.m., July 27, 2012.
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Update: 27.07.2012
The unmanned, school bus-size H-2 Transfer Vehicle-3 (HTV-3), also called Kounotori 3 ("White Stork" in Japanese), flew to about 40 feet (12 meters) away from the ISS, where it was grabbed at 8:23 a.m. ET (1223 GMT) by the space station's 58-foot long (18 m) robotic arm, which was controlled from inside by astronauts Joe Acaba of NASA and Aki Hoshide of JAXA (the Japanese Aerospace Exploration Agency).
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The HTV-3 cargo ship, moments before capture by the International Space Station's robot arm. (Photo: NASA TV)
"HTV capture is complete," Hoshide called down after the spacecraft was grappled at 8:23 a.m. EDT (GMT-4). "Congratulations to all the teams in Houston and (Japan)."

Spectacular video from the station showed the bus-size HTV suspended against the black backdrop of space as the two spacecraft sailed 253 miles above the southern Indian Ocean.

"Congratulations on a great capture. We'd like to welcome Kounotori aboard," astronaut Catherine Coleman replied from Houston, referring to the cargo craft's Japanese nickname -- "white stork."

After carefully aligning the HTV's forward hatch with Harmony's Earth-facing port, a gang of motorized bolts were driven home to lock the spacecraft in place by 10:34 a.m. Hatches were scheduled to be opened Saturday, but the astronauts were running ahead of schedule and they had the option of entering the craft earlier if time allowed.

Developed by the Japan Aerospace Exploration Agency, or JAXA, as a contribution to the space station program, the HTV is designed to carry both pressurized and unpressurized cargo, including equipment too big to pass through the space station's hatches.

Making the program's third flight, the HTV is loaded with 3.9 tons of pressurized cargo, including a research aquarium, five small "CubeSat" satellites and their launcher, a catalytic reactor for the station's water processing system and a water pump. Also on board: Japanese food, beverages and crew clothing.

The HTV is carrying another 1.2 tons of gear in its unpressurized section, including experimental NASA communications hardware and instruments and sensors that will be mounted outside the Japanese Kibo lab module.

The flight plan calls for the cargo ship to remain in place until Sept. 6.
Update: 28.07.2012 / 22.30 MESZ
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KOUNOTORI3's berthing operations began. The Space Station Remote Manipulator System (SSRMS) will attach KOUNOTORI3 to a Common Berthing Mechanism (CBM) at the nadir port of Harmony (Node2).

The berthing operations will be completed when the CBM between KOUNOTORI and Harmony is fastened with CBM bolts, and all the electrical lines and communications cables between the two modules are connected.

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The Common Berthing Mechanism (CBM) between KOUNOTORI3 and Harmony was fastened with bolts at 0:22 a.m., July 28.

The ISS crew members will open the hatch of the Harmony nadir port to perform electrical and communications cable connections (vestibule outfitting).

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Samstag, 28. Juli 2012 - 16:00 Uhr

Mars-Chroniken - Windtunnel-Test von Curiosity´s Fallschirm

 

 

Wind tunnel testing at Cleveland's NASA Glenn Research Center boosts confidence in Curiosity rover's Mars parachute

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As the Mars rover Curiosityscreams from space down to the Red Planet's surface next Sunday night, it will endure more aerobatic twists than a Cirque du Soleil trapeze artist.

First it will blaze through the upper atmosphere like a fireball, then it will be slowed by a supersonic parachute, and finally it will dangle from a rocket-powered "sky crane" before gently touching down on the rusty Martian soil.

NASA calls the complicated, harrowing descent "seven minutes of terror." The outcome of two of those minutes, during which the rover will hang below the biggest parachute ever deployed on Mars while falling at hundreds of miles an hour, hinges in part on testing done at Cleveland's Glenn Research Center.

The three months of wind tunnel trials here in 2008 helped convince NASA Jet Propulsion Laboratory engineers overseeing the mission that the chute and its $1.8 billion passenger could safely withstand a scary-looking aerodynamic quirk called "area oscillation."

The phenomenon, captured by high-speed cameras during the Glenn tests, repeatedly causes the canopy to partially collapse, then re-inflate, in the supersonic slipstream, billowing like the folds of a sea creature.

"The way the parachute was oscillating was kind of like a squid or an octopus," said Christine Pastor-Barsi, an aero-mechanical test engineer with Glenn contractor Sierra-Lobo Inc. who participated in the testing. "It was really cool looking, actually."

Maybe. But it would be extremely uncool if a chute failure ended the ambitious Mars Science Laboratory mission before the rover was even on the ground.

"We have an almost unprecedented level of confidence that this [landing] is going to work," said JPL aerospace engineer Devin Kipp, who's in charge of the parachute portion of Curiosity's descent. "But at the same time, this is the most complex thing we've ever attempted" on Mars, "and it has the most number of wild-card, random variables that could go wrong."

So NASA engineers pored over every aspect of what's called EDL, or entry, descent and landing.

The space agency's three previous Mars rovers – Sojourner, in 1997, and the twins Spirit and Opporunity, in 2004 – used a sequence of heat shield, parachute, retro rockets and a protective cocoon of airbags to slow their plummet through the planet's thin atmosphere and cushion their bouncing arrival.

But at nearly a ton, the Mini Cooper-sized Curiosity is five times heavier than either Spirit or Opportunity, and a whopping 86 times the mass of tiny Sojurner, which was no bigger than an adult beagle. The tried-and-true airbags –bounce-tested years ago on simulated Martian rocks inside the giant vacuum chamber at NASA's Plum Brook Station near Sandusky – couldn't handle Curiosity's bulk.

So NASA ditched the airbags in favor of the "sky crane." It's a sort of jet pack on steroids that will hover while gently lowering Curiosity to the ground on a tether, then fly a safe distance away and crash. The sky crane not only can handle heavy-lifting, but it provides a far more precise landing spot than the careening air bags. "It looks crazy, but it's well-reasoned," Kipp said.

For the maneuver to work, though, Curiosity's initial descent still has to be slowed by a heat shield, and the supersonic parachute.

Fortunately, a lot of what NASA needed to know about parachute behavior in the wispy Martian atmosphere had already been worked out in preparation for the Viking Mars lander missions in 1976. There were well-documented chute inflation tests in Earth's thin stratosphere, and drop tests with dummy loads. Having those results saved the Curiosity team months of work and millions of dollars in costs.

But there were still differences, and some unknowns, that could affect performance and had to be checked out.

Curiosity's chute would have to be bigger than Viking's – 70 feet across, compared to 53 – to handle the rover's additional weight and its bullet-fast, supersonic 900 mph speed when the canopy unfurls. Its fabric is nylon, not Viking's disco-era polyester, and its suspension cords substitute Kevlar for Viking's more stretchy Dacron.

The engineers needed to know that Curiosity's canopy material wouldn't suffer damaging friction burns when it burst from its packing bag during deployment. (It didn't.)

And they needed to get to the bottom of some odd flight data readings that had showed up just seconds after NASA's Phoenix Mars lander opened its Viking-style parachute, en route to a successful 2008 landing near Mars' north polar ice cap.

The readings seemed to indicate the Phoenix chute was undergoing the jellyfish-like undulations of area oscillation, partially deflating and refilling, over and over. "There was a lot of concern that this is a phenomenon we [didn't] have a good physical understanding of," said Kipp.

Since Curiosity's chute would be 33 percent larger than the Viking and Phoenix canopies, "we had to convince ourselves that, by making it bigger, we weren't introducing any new physics that Viking [and Phoenix] didn't have to deal with," Kipp said.

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To tackle the problem, JPL and Stanford University engineers used data from the 1970s Viking parachute tests to program a computer model that could predict how Curiosity's canopy would behave. The JPL Curiosity team also commissioned the chute tests at Glenn's supersonic wind tunnel, which could mimic the punishing conditions of the rover's Mars descent.

At 10 feet tall, 10 feet wide and 48 feet long, the Glenn facility is the largest supersonic wind tunnel in the country. Built in the early 1950s, and still operating with its original compressors and drive motors, the "10 by 10" can whip up a gale that dwarfs the worst hurricane on record.

CLEVELAND, Ohio — Its Mach 3.5 top speed (3.5 times the speed of sound, or 2,664 mph) is so powerful that grains of dirt become damaging projectiles, requiring that the tunnel be kept scrupulously clean. Over the years, the 10 by 10 has tested scaled-down models or components of everything from the SR-71 Blackbird spy plane and the space shuttle to the Saturn moon rocket.

The Curiosity chute tests at Glenn were only meant to study chute motion, not durability, and their Mach 2-2.5 wind speeds were considerably higher than what the rover's canopy will experience at Mars. So the scaled-down 2-feet-wide mini-chutes lasted only a couple of seconds in the howling tunnel before ripping apart.

But in that blink of an eye, ultra-fast specialized cameras helped the engineers see what was going on. Optical tricks allowed them to visualize two supersonic shock waves, one created by air striking the chute, and the other building up around Curiosity's protective capsule.

In video footage from one of the tests, the chute's shock wave looks like a writhing alien blob, spilling out from under the canopy and snaking along its cords as if alive. "It was kind of crawling up those suspension lines," said Glenn mechanical engineer Jim Roeder, who led the wind tunnel tests.

In certain supersonic conditions, those two separate "bow shocks" can mingle in the space between capsule and chute, causing turbulence that makes the canopy repeatedly sag, then recover.

Creating more distance between canopy and capsule by lengthening the chute's cords could alter the shock wave patterns and ease the area oscillations. "Right now, the suspension lines are 50 meters long," Kipp said. "If we made them 80 or 100 meters, this problem would start to go away."

But longer cords would be heavier and bulkier, eating up precious room and fuel on the spacecraft delivering Curiosity to Mars. The Glenn wind tunnel tests helped convince the JPL team that the oscillations wouldn't fully collapse Curiosity's chute. And hundreds of thousands of computer simulations showed that the chute's billowing during descent barely affected the rover's carefully planned trajectory down to the surface.

"We felt like we had tested and analyzed ourselves out of being concerned about this problem," Kipp said.

The NASA engineers won't know whether that confidence is justified until early on the morning of August 6, when they'll listen and hope for Curiosity's report that it has safely touched down. The parachute is just one of many components that must work for the rover to survive. "Entry, descent and landing is like a game of dominoes," NASA's Mars Exploration Program director Doug McCuistion said in a recent news briefing. "If one of them is out of place, it's very likely that the last domino won't fall."

The "seven minutes of terror" landing sequence is automated, so all everyone can do at that point is wait. The JPL team has rehearsed, Kipp said, and "seven minutes feels like a long time, even when you know it's a test."

The nearly 14 minutes it takes a radio message to cross the 154 million miles from Mars to Earth will heighten the suspense. "By the time we're getting the signal that [Curiosity] is entering the atmosphere, we will already have been on the ground for seven minutes," Kipp said. "One way or the other."

What he means is the rover will either be down in one piece, or in a million pieces.

NASA's track record for landing spacecraft on Mars is an admirable seven of eight, so the odds favor Curiosity. "If it doesn't work, you're always going to wonder what else I could have done with the last 10 years of my life," Kipp said. "But I think everybody feels they've done everything they can. The team as a whole doesn't have any lingering concerns."

At Glenn, the engineers who tested Curiosity's parachute design have moved on to other work, but they'll closely follow its final approach to Mars. Roeder plans to stay up late, watching the landing coverage on TV.

"I think everybody here feels a little part of the effort," he said. "If it doesn't land correctly, I think we're all going to feel it."

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Samstag, 28. Juli 2012 - 09:00 Uhr

Raumfahrt - Erfolgreicher Start von Dänemark Smaragd-1 Rakete

 

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A Danish group of amateur spaceflight enthusiasts launched a homemade rocket Friday (July 27) on a trial flight to test vital technologies for a private manned spacecraft.

The team Copenhagen Suborbitals launched its two-stage unmanned rocket SMARAGD-1 from a floating platform in the Baltic Sea to test long-range communications gear, rocket stage separation systems and other equipment needed for its planned larger crewed spaceship. The rocket was expected to reach an altitude of about 12 miles (20 kilometers) during the test flight, according to a mission description.

The launch marked the first mission for the non-profit Copenhagen Suborbitals since a 2011 test flight of its HEAT-1X rocket and a space capsule prototype. The group is now developing a small, one-person space capsule (called Tycho Deep Space) that resembles a miniature Apollo spacecraft.


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Freitag, 27. Juli 2012 - 15:00 Uhr

UFO-Forschung - Kinder und UFOs

 

Auf der empfehlenswerten Webseite; http://www.ufo-information.de/ gibt es seit heute eine informative Seite für Kinder welche ihnen die Welt der Ufos erklärt!

 

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Bereits im Frühjahr 2011 hielt CENAP in einer Grundschule bei Heidelberg einen Astronomie+Ufo-Vortrag vor Schülern aus der 3 und 4 Klasse welche sich im Alter von 10-12 befanden. Bereits Wochen zuvor wurde das Thema Weltraum und Außerirdische im Unterricht klassenübergreifend behandelt. Abgeschlossen wurde es im Zeichenunterricht : Wie stell ich mir ein Ufo vor und mit Fragebriefen an CENAP, H.Köhler und deren Fragen im Vortrag beantwortet wurden.

Nachfolgend die Zeichnungen der Schüler, welche CENAP zur weiteren Verwendung überlassen wurden:

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Beispiel-Brief der Kinder, Michelle 10 Jahre:

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Freitag, 27. Juli 2012 - 14:23 Uhr

Mars-Chroniken - Mars Express unterstützt Curiosity-Landung der NASA auf dem Mars

 

 

Presseeinladung: Mars Express unterstützt Curiosity-Landung der NASA auf dem Mars
 
27 Juli 2012
Wir laden Medienvertreter ein, am 6. August am ESOC in Darmstadt mitzuverfolgen, wie der ESA-Orbiter Mars Express die NASA-Sonde MSL / Couriosity beim Eintritt in die Mars-Atmosphäre, bei der Abstiegsphase und Landung auf dem Mars unterstützt.
 
Die MSL-Sonde (Mars Science Laboratory) der NASA soll an diesem Tag den Rover Curiosity auf der Oberfläche des Roten Planeten aussetzen.
Die Landung im Gale-Krater markiert den Beginn eines ehrgeizigen Explorationsprogramms zur Erforschung der Bewohnbarkeit, des Klimas und der Geologie des Mars sowie zur Sammlung von Daten für eine künftige bemannte Marsmission.
Während der kritischen Eintritts-, Abstiegs- und Landephase von MSL, die voraussichtlich zwischen 6.15 Uhr und 7.30 Uhr MESZ stattfindet, wird der ESA-Orbiter Mars Express komplexe Befehle und Daten für die Bahnverfolgung übertragen.  
Der europäische Orbiter wird sich nämlich in einer idealen Position zur Aufnahme von Signalen des NASA-Landegeräts befinden, so dass Wissenschaftler mit seiner Hilfe die Eintritts- und Landephase in ihren Einzelheiten nachvollziehen und somit eine genauere Kenntnis der Marsatmosphäre erlangen können.
Die Bestätigung der Landung durch die NASA soll um 7.31 MESZ erfolgen.
Die Bahnverfolgungs- und anderen Daten, die die ESA mit Mars Express bereitstellt, bilden sind eine wichtige Stütze für die Raumflugkontrolle durch die NASA.
Das ESA-Bodenstationsnetz mit seinen 35 m-Antennen für interplanetare Missionen wird die Landung ebenfalls unterstützen. Im Notfall kann es für das NASA-eigene Antennennetz für interplanetare Missionen einspringen. 
Presseeinladung ins ESOC in Darmstadt Vertreter der Medien sind somit am 6. August eingeladen, die Mission im Europäischen Satellitenkontrollzentrum der ESA in Darmstadt live mitzuverfolgen. Kommentiert wird die Veranstaltung vom ESA-Direktor für bemannte Raumfahrt und Betrieb, Thomas Reiter, sowie von führenden Mars-Wissenschaftlern der ESA.
Darüber hinaus werden auch die Unterstützungstätigkeiten der ESA für laufende und frühere NASA-Missionen sowie die langjährige Zusammenarbeit zwischen ESA und NASA beim Missionsbetrieb und in der Weltraumforschung vorgestellt.   Veranstaltungsprogramm: 06:00-09:00 Uhr 06:00 Uhr: Einlass06:30 Uhr: Eröffnung durch Thomas Reiter, ESA-Direktor für bemannte Raumfahrt und Betrieb und Leiter des ESOC06:35 Uhr: Europa auf dem Mars – 8 Jahre wissenschaftliche Forschung mit Mars Express, Mark McCaughrean, ESA-Leiter für Forschungs- und Wissenschaftsunterstützung06:50 Uhr: Präsentation der Unterstützungstätigkeiten von Mars Express für die NASA-Sonde MSL, Michel Denis, Mars Express-Flugbetriebsleiter07:05 Uhr: Live-Übertragung der Eintritts-, Abstiegs- und Landungsphase von MSL durch NASA-TV, moderiert von Paolo Ferri, ESA-Leiter für den Flugbetrieb von Planetenmissionen07:31 Uhr: voraussichtliche Bestätigung der Landung von MSL auf dem Mars07:50 Uhr: Zusammenfassung des Programms, Manfred Warhaut, Leiter der ESA-Abteilung für Missionsbetrieb08:00 Uhr: Gelegenheiten für Interviews, Fragen und Antworten09:00 Uhr: Ende der Veranstaltung
Live-Übertragung per Streaming
Am 6. August können außerdem Präsentationen von Experten und Beiträge über die technischen Arbeiten im Raumflugkontrollzentrum der ESA zwischen 6.30 Uhr und 8 Uhr MESZ live per Streaming über folgenden Link abgerufen werden: www.livestream.com/eurospaceagency 
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Fotos+Quelle: ESA
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Freitag, 27. Juli 2012 - 14:00 Uhr

Astronomie - Staubwirbel auf Mond entdeckt

 

Scientists in the UK have solved a long-standing mystery on the Moon - and their solution could help develop a shield to protect astronauts against deadly radiation.
A team from RAL Space at the Rutherford Appleton Laboratory in Oxfordshire looked at so-called lunar swirls - patches of pale soil on the Moon, some several tens of kms across, for which there had been no ready explanation before.
They identified that small scale magnetic bubbles - miniature versions of the field that protects the Earth - were deflecting the blast from the solar wind that was bombarding the Moon.
The scientists, led by Dr Ruth Bamford, combined the space data with experiments in a "solar wind tunnel" to construct an experimental magnetic shield that might protect explorers in their journeys between the planets.
Radiation from powerful solar flares, which can occur at any time, are one of the biggest hazards confronting long-distance space travellers because of the high levels of radiation they can produce.
There are already safety areas on the International Space Station where astronauts can shelter. But on a journey to Mars the prospect of bad space weather is a very worrying one.
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Foto:NASA
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The RAL team realised that understanding just how the "mini-magnetospheres" on the Moon produce a cavity in the solar wind to drive away the solar wind could help them design a mechanism to protect space explorers. Scientists at the University of York in the UK have now managed to create similar "bubbles" in the laboratory.
Dr Bamford said: "Close to the moon's surface, the strength of a magnetic anomaly is likely to be very irregular, featuring overlapping "cavities" and "gradients". Over an estimated 3.8 billion years these anomalies would have been deflecting the solar wind particles streaming in from space, slowly creating these amazing patterns, which can be clearly seen on the lunar surface today.
"We still need to determine quite how effective this mechanism would be at deflecting the real hazardous higher energy particles. The jury is still out on that one, but such an active shield could make the difference between survivable and certain death for astronauts on their way to Mars."
Dr Bamford added: "When we first tried the experiment in the Solar Wind Tunnel and it worked, it was very exciting. The active force which deflect the solar wind particles is electric not magnetic. The electric field is created naturally by the edges of the moon's magnetic 'bubbles".

"What matters is the "gradient" in the magnetic field, rather than the overall size of the magnetic bubble. So they can be as small as you like - as long as the gradient is steep enough ".

Dr Bamford has long been experimenting on building a protective shield, using a shop-bought magnet for earlier tests. She told this writer: "These initial experiments have shown promise and it may be possible to shield astronauts from deadly space weather. NASA have shown a lot of interest in our work. We've shown this is possible and not just science fiction. It is all very encouraging."

Dr Bamford, who thought it might take 15-20 years to develop a full-scale model for a real spaceship, pointed out that science fiction shows had got their ideas for defence fields from the Earth's own protective field. She told me: "The shields in Star Trek were inspired by the magnetosphere in the first place."

The most striking lunar swirl is called Reiner Gamma and can be seen from Earth with a good telescope. The picture above was taken by NASA's Lunar Reconnaissance Orbiter probe in orbit around the Moon.

Quelle: SEN

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Freitag, 27. Juli 2012 - 11:45 Uhr

Raumfahrt - 9 Tage-Countdown für Mars-Rover Curiosity

 

 

 

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Frams: NASA-TV

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Freitag, 27. Juli 2012 - 10:14 Uhr

Astronomie - Neues Auge mustert den Gammahimmel

 

 

Weltgrößtes Tscherenkow-Teleskop H.E.S.S. II sah heute sein erstes Licht
Das Gamma-Auge in Namibia hat erheblich an Sehschärfe gewonnen: Das neue Teleskop H.E.S.S. II besitzt einen 28-Meter-Spiegel und ergänzt seit heute das aus vier 12-Meter-Spiegeln bestehende H.E.S.S.-Observatorium (High Energy Stereoscopic System). Das größte jemals gebaute Tscherenkow-Teleskop wird die energiereichsten und extremsten Phänomene im Universum im sehr hochenergetischen Gammalicht beobachten. Von dem Instrument nahe des Gamsbergs versprechen sich die Forscher ein tieferes Verständnis bekannter hochenergetischer kosmischer Strahlungsquellen wie supermassiver schwarzer Löcher, Pulsare und Supernovae.
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Das neue Teleskop wiegt fast 600 Tonnen, sein 28-Meter-Spiegel entspricht der Fläche von zwei Tennisplätzen. Am 26. Juli um 0:43 Uhr MEZ hat es „erstes Licht“ gesehen und Bilder von atmosphärischen Teilchenschauern aufgenommen, die von kosmischen Gammastrahlen oder von kosmischer Strahlung erzeugt werden. „Das neue Teleskop hat nicht nur die weltweit größte Spiegelfläche derartiger Instrumente, sondern es löst auch die Bilder der Teilchenschauer mit beispiellosem Detailreichtum auf, da es viermal mehr Pixel pro Himmelsfläche besitzt als die kleineren Teleskope“, sagt Pascal Vincent von dem französischen Team, das für die Lichtsensor-Einheit (Kamera) im Fokus des Spiegels verantwortlich ist.
Gammastrahlen stammen nach heutigem Verständnis der Astrophysik aus natürlichen kosmischen Teilchenbeschleunigern wie supermassiven schwarzen Löchern, Doppelsternen, Pulsaren, Galaxienhaufen und Supernovae oder auch von Teilchen aus dem Urknall. Im Universum gibt es viele solcher natürlichen Beschleuniger, die geladene Teilchen auf weit höhere Energieniveaus bringen als dies in künstlichen Beschleunigern wie dem LHC am Genfer CERN der Fall ist.
Hochenergetische Gammastrahlen sind Sekundärprodukte dieser Prozesse und lassen sich daher mit für dieses Licht sensiblen Teleskopen untersuchen. Bisher kennen die Wissenschaftler mehr als 100 kosmische Quellen höchstenergetischer Gammastrahlen. Mit H.E.S.S. II werden die Astrophysiker nicht nur diese Objekte detaillierter erforschen, sondern wohl auch viele neue Quellen entdecken.
Insbesondere wird H.E.S.S. II den Gammastrahlenhimmel bei Energien im Bereich von einigen zehn Gigaelektronenvolt erkunden – also im wenig untersuchten Übergangsbereich zwischen Weltrauminstrumenten und den derzeitigen Teleskopen am Boden, der ein riesiges Potenzial für Entdeckungen bietet.
Hinter den extremsten Gammastrahlern verbergen sich aktive Galaxienkerne. Sie leuchten etwa hundertfach so hell wie die gesamte Milchstraße; dabei scheint die Energie aus einem Volumen zu kommen, das deutlich kleiner ist als das unseres Sonnensystems. Zudem ändert sich die Intensität der Strahlung innerhalb von Minuten dramatisch – ein Hinweis auf die Existenz von supermassiven schwarzen Löchern, die gierig Materie aus der Umgebung verschlingen und dabei Strahlung abgeben.
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Die H.E.S.S.-Teleskope haben in den vergangenen Jahren einige Quellen entdeckt, die bei anderen Wellenlängen unsichtbar sind. Dabei könnte es sich um einen neuen Typ von Himmelsobjekten handeln, zu deren Entschlüsselung H.E.S.S. II beitragen wird.
Dabei beobachtet H.E.S.S. das All nicht direkt wie etwa optische Fernrohre. Wenn Gammastrahlen hoch in der irdischen Atmosphäre auf Luftmoleküle treffen, erzeugen sie eine Kaskade von Sekundärteilchen (Teilchenschauer). Diese Tscherenkow-Strahlung zeigt sich als bläuliche Lichtblitze, die Teleskope mit ultraschnellen Kameras am Boden registrieren. Die für H.E.S.S. II entwickelte Kamera ist in der Lage, die sehr schwachen Blitze mit einer Belichtungszeit von einigen Milliardstel Sekunden aufzunehmen, also eine Million mal schneller als eine normale Kamera.
Die H.E.S.S.-II-Kamera hat die Fläche eines Garagentors, wiegt etwa drei Tonnen und liegt 36 Meter über dem Spiegel in der Brennebene – bei aufrechter Position auf der Höhe eines 20-stöckigen Gebäudes. Trotz seiner Größe kann das Teleskop doppelt so schnell wie die kleineren Teleskope schwenken, um sofort auf schnelle und kurzzeitige Phänomene wie Gammastrahlenausbrüche irgendwo am Firmament zu reagieren.
Die Teleskopstruktur und das Antriebssystem wurden von Ingenieuren in Deutschland und Südafrika entwickelt und in Namibia und Deutschland gebaut. Die 875 sechseckigen Spiegelfacetten, aus denen der riesige Reflektor besteht, wurden in Armenien hergestellt. Die Kamera mit integrierter Elektronik wurde in Frankreich entwickelt und gebaut. Der Bau des neuen H.E.S.S.-II-Teleskops wurde hauptsächlich von deutschen und französischen Institutionen vorangetrieben und finanziert; wesentliche Beiträge kamen aus Österreich, Polen, Südafrika und Schweden.
Das Heidelberger Max-Planck-Institut für Kernphysik war an der Entwicklung und dem Design aller Komponenten außer der Kamera und ihrer Elektronik maßgeblich beteiligt und koordinierte die Aufbauarbeiten. Die Max-Planck-Gesellschaft war mit einem Anteil an der Finanzierung von knapp 50 Prozent der mit Abstand größte Geldgeber für H.E.S.S. II.
„Die erfolgreiche Inbetriebnahme des neuen Teleskops ist ein großer Schritt voran für die Wissenschaftler von H.E.S.S., für die astronomische Forschung insgesamt und für das südliche Afrika als erstklassigen Standort“, sagt Werner Hofmann, Direktor am Max-Planck-Institut für Kernphysik und Sprecher des Projekts. „H.E.S.S. II ebnet auch den Weg zur Realisierung von CTA, dem Cerenkov Telescope Array. Das ist die nächste Instrumentengeneration mit höchster Priorität bei Astroteilchenphysikern in Europa.“
Das H.E.S.S.-Observatorium wird seit fast einem Jahrzehnt von einer Kollaboration betrieben, der mehr als 170 Wissenschaftler aus 32 Institutionen in zwölf verschiedenen Ländern angehören: Namibia und Südafrika, Deutschland, Frankreich, Großbritannien, Irland, Österreich, Polen, Tschechien, Schweden, Armenien und Australien. Bisher hat die H.E.S.S.-Kollaboration mehr als 100 Artikel in wissenschaftlichen Zeitschriften veröffentlicht.
Im Jahr 2006 erhielt H.E.S.S. den Descartes-Preis der Europäischen Kommission – die höchste Auszeichnung für wissenschaftliche Zusammenarbeit – und 2010 den Rossi-Preis der Amerikanischen Astronomischen Gesellschaft. In einer Übersicht über die einflussreichsten Observatorien weltweit kam H.E.S.S. im Jahr 2006 auf den zehnten Platz und damit in die Nähe des Hubble Weltraumteleskops und der Europäischen Südsternwarte ESO in Chile.
Quelle: MPI

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