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Sonntag, 12. Juni 2016 - 18:30 Uhr

Astronomie - NASA bestätigt Objekt über St. Louis war ein Tages-Meteor

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ST. LOUIS, MO (KTVI) – An out of this world sight dozens of people spotted in the sky over St. Louis earlier this week was in deed a meteor. NASA reports that it was a meteor that burned up along a 25 mile track, starting near Hannibal. It was about 30 miles above earth.
The meteor was traveling about 49,000 miles per hour, so it didn’t take long to disappear. Nearly 300 people reported seeing it.
Quelle: FOX2
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6.06.2016

Did you see it? Viewers report seeing object ‘flash’ over St. Louis

ST. LOUIS, MO (KTVI) – Several FOX 2 viewers have called in say they saw something fly over the area at around 11:40am.  Meterologist Angela Hutti captured something on one of our cameras stationed at Eckert’s Farm in Belleville.  Others report seeing the object  across the viewing area.
Tom Stolze posted a video of what he is calling a meteor to YouTube today.  He writes, “Our outdoor camera caught footage of a meteor today to the NW of O’Fallon, MO located west of St. Louis, MO.”
Rich Loeschner writes, “I believe I just saw a small meteor fall somewhere by St. Charles. I was driving west bound on 370 when I saw a streak of light come straight down and went out about 200 yard in the air. I thought I heard a faint explosion. Looked like a small firework but very bright!”
Quinton LeJeune sent this message to FOX 2, “I seen the meteor just northwest of Moscow mills from hwy U/ us 61 it was really cool it was green blue red and yellow”
“I saw what I thought was a flair in Clayton about the time others were reporting the meteor. It looked to be right over Brentwood Blvd and Forest Park express way. wrote Denise Hayes Bolds.
“I saw that flash of light today around 11:40am near page and Lindbergh. I wasn’t sure what it was.” Tashishia posted to FOX 2’s Facebook messages.
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Quelle: FOX2

Tags: Astronomie 

1867 Views

Sonntag, 12. Juni 2016 - 17:00 Uhr

Astronomie - Haben je außerirdische Zivilisationen jemals existiert? Astronomen sagen, die Chancen sind himmelhoch

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Ellie Arroway (played by Jodie Foster) listens for alien signals in the movie “Contact.” (Credit: Warner Bros.)
Are we alone? Fifty-five years ago, astronomer Frank Drake came up with an equation that weighed the odds for aliens, and now two astronomers have tweaked the formula to come up with a slightly different spin.
Their bottom line? There’s an astronomically high chance that other civilizations have arisen elsewhere in the universe at some point in its 13.8 billion-year history.
The University of Washington’s Woody Sullivan and the University of Rochester’s Adam Frank published their assessment in the May issue of Astrobiology, and Frank is following up with an op-ed in Sunday’s New York Times.
“While we do not know if any advanced extraterrestrial civilizations currently exist in our galaxy, we now have enough information that they almost certainly existed at some point in cosmic history,” Frank writes.
He and Sullivan come to that conclusion by deconstructing the Drake Equation. The classic formula starts out with the rate of formation of stars in our Milky Way galaxy, then multiplies that by the fraction of those stars with planetary systems, the average number of habitable planets for each of those systems, the fraction of those planets that give rise to life, the fraction of those life-bearing planets that give rise to civilizations, the fraction of those civilizations that beam out evidence of their existence, and the average length of time during which they’re able to do the beaming. The result tells you how many alien civilizations in the Milky Way you think should be sending out signals.
Simple, right? You can use this interactive to plug in your own estimates and come up with a figure.
The problem is that the latter terms of the equation are squishy, because we just don’t know enough about life beyond Earth to hazard an educated guess. But thanks to the data from NASA’s planet-hunting Kepler space telescope, astronomers are getting a good handle on the first three terms: the number of stars, planetary production and the prevalence of habitable planets.
So Frank and Sullivan focus on what’s known about the big picture, and set aside the time factor.
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The Drake Equation, top, combines several factors to come up with an estimate for the number of extraterrestrial civilizations in the Milky Way currently beaming out signals. The Frank-Sullivan Equation, bottom, eliminates the time factors and provides an estimate for the number of advanced cvilizations likely to have developed over the history of the observable universe. Click on the graphic for a larger version. (Credit: University of Rochester)
They start out with an estimate of 20 sextillion stars in the observable universe (2 x 1022). There appears to be at least one planet for every star (1.0). And about one-fifth of those planets appear to orbit in habitable zones (0.2). That gives you a really big number for the estimate of habitable planets in the universe: 4 sextillion, or 4 x 1021.
Then the astronomers add a twist to the equation. How low do you have to set the chances that a habitable planet gives rise to a signal-beaming civilization, in order to reduce what you get when you do the multiplication (planets times probability) to just one world, as in Earth? The number would have to be one chance in 4 sextillion, or 2.5 x 10-22.
“To me, this implies that other intelligent, technology-producing species very likely have evolved before us,” Frank said in a news release about the tweaked equation. “Think of it this way: Before our result you’d be considered a pessimist if you imagined the probability of evolving a civilization on a habitable planet were, say, one in a trillion. But even that guess, one chance in a trillion, implies that what has happened here on Earth with humanity has in fact happened about 10 billion other times over cosmic history!”
Or as Carl Sagan put it in “Contact,” the novel that was made into a movie starring Jodie Foster: “If it’s just us, seems like an awful waste of space.”
Sullivan pointed out that there’s still room to be pessimistic about the search for extraterrestrial intelligence.
“The universe is more than 13 billion years old,” he said. “That means that even if there have been a thousand civilizations in our own galaxy, if they live only as long as we have been around — roughly 10,000 years — then all of them are likely already extinct. And others won’t evolve until we are long gone. For us to have much chance of success in finding another ‘contemporary’ active technological civilization, on average they must last much longer than our present lifetime.”
On one level, calculating the odds for alien life is just a numbers game. But on a deeper level, it should get us thinking about what it takes to make a civilization sustainable for the long term — so that we can stick around long enough to make our own mark in the cosmos.
Quelle: GeekWire
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Yes, There Have Been Aliens

LAST month astronomers from the Kepler spacecraft team announced the discovery of 1,284 new planets, all orbiting stars outside our solar system. The total number of such “exoplanets” confirmed via Kepler and other methods now stands at more than 3,000.
This represents a revolution in planetary knowledge. A decade or so ago the discovery of even a single new exoplanet was big news. Not anymore. Improvements in astronomical observation technology have moved us from retail to wholesale planet discovery. We now know, for example, that every star in the sky likely hosts at least one planet.
But planets are only the beginning of the story. What everyone wants to know is whether any of these worlds has aliens living on it. Does our newfound knowledge of planets bring us any closer to answering that question?
A little bit, actually, yes. In a paper published in the May issue of the journal Astrobiology, the astronomer Woodruff Sullivan and I show that while we do not know if any advanced extraterrestrial civilizations currently exist in our galaxy, we now have enough information to conclude that they almost certainly existed at some point in cosmic history.
Among scientists, the probability of the existence of an alien society with which we might make contact is discussed in terms of something called the Drake equation. In 1961, the National Academy of Sciences asked the astronomer Frank Drake to host a scientific meeting on the possibilities of “interstellar communication.” Since the odds of contact with alien life depended on how many advanced extraterrestrial civilizations existed in the galaxy, Drake identified seven factors on which that number would depend, and incorporated them into an equation.
The first factor was the number of stars born each year. The second was the fraction of stars that had planets. After that came the number of planets per star that traveled in orbits in the right locations for life to form (assuming life requires liquid water). The next factor was the fraction of such planets where life actually got started. Then came factors for the fraction of life-bearing planets on which intelligence and advanced civilizations (meaning radio signal-emitting) evolved. The final factor was the average lifetime of a technological civilization.
Drake’s equation was not like Einstein’s E=mc2. It was not a statement of a universal law. It was a mechanism for fostering organized discussion, a way of understanding what we needed to know to answer the question about alien civilizations. In 1961, only the first factor — the number of stars born each year — was understood. And that level of ignorance remained until very recently.
That’s why discussions of extraterrestrial civilizations, no matter how learned, have historically boiled down to mere expressions of hope or pessimism. What, for example, is the fraction of planets that form life? Optimists might marshal sophisticated molecular biological models to argue for a large fraction. Pessimists then cite their own scientific data to argue for a fraction closer to 0. But with only one example of a life-bearing planet (ours), it’s hard to know who is right.
Or consider the average lifetime of a civilization. Humans have been using radio technology for only about 100 years. How much longer will our civilization last? A thousand more years? A hundred thousand more? Ten million more? If the average lifetime for a civilization is short, the galaxy is likely to be unpopulated most of the time. Once again, however, with only one example to draw from, it’s back to a battle between pessimists and optimists.
But our new planetary knowledge has removed some of the uncertainty from this debate. Three of the seven terms in Drake’s equation are now known. We know the number of stars born each year. We know that the percentage of stars hosting planets is about 100. And we also know that about 20 to 25 percent of those planets are in the right place for life to form. This puts us in a position, for the first time, to say something definitive about extraterrestrial civilizations — if we ask the right question.
In our recent paper, Professor Sullivan and I did this by shifting the focus of Drake’s equation. Instead of asking how many civilizations currently exist, we asked what the probability is that ours is the only technological civilization that has ever appeared. By asking this question, we could bypass the factor about the average lifetime of a civilization. This left us with only three unknown factors, which we combined into one “biotechnical” probability: the likelihood of the creation of life, intelligent life and technological capacity.
You might assume this probability is low, and thus the chances remain small that another technological civilization arose. But what our calculation revealed is that even if this probability is assumed to be extremely low, the odds that we are not the first technological civilization are actually high. Specifically, unless the probability for evolving a civilization on a habitable-zone planet is less than one in 10 billion trillion, then we are not the first.
To give some context for that figure: In previous discussions of the Drake equation, a probability for civilizations to form of one in 10 billion per planet was considered highly pessimistic. According to our finding, even if you grant that level of pessimism, a trillion civilizations still would have appeared over the course of cosmic history.
In other words, given what we now know about the number and orbital positions of the galaxy’s planets, the degree of pessimism required to doubt the existence, at some point in time, of an advanced extraterrestrial civilization borders on the irrational.
In science an important step forward can be finding a question that can be answered with the data at hand. Our paper did just this. As for the big question — whether any other civilizations currently exist — we may have to wait a long while for relevant data. But we should not underestimate how far we have come in a short time.
Quelle: The New York Times

Tags: Astronomie die Chancen sind himmelhoch 

1559 Views

Sonntag, 12. Juni 2016 - 14:30 Uhr

Raumfahrt - Mars-Curiosity-Chroniken - Curiosity-News Sol 1301-1317

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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1301 (2016-04-03 15:42:50 UTC). 
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1301 (2016-04-03 15:45:06 UTC). 
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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 1301 (2016-04-03 15:47:55 UTC). 
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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 1301 (2016-04-03 15:51:20 UTC). 
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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 1301 (2016-04-03 16:02:29 UTC). 
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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 1301 (2016-04-03 16:08:07 UTC). 
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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 1301 (2016-04-03 16:15:39 UTC). 
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This image was taken by Mars Descent Imager (MARDI) onboard NASA's Mars rover Curiosity on Sol 1301 (2016-04-04 02:38:27 UTC). 
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This image was taken by Navcam: Left B (NAV_LEFT_B) onboard NASA's Mars rover Curiosity on Sol 1301 (2016-04-03 23:01:13 UTC). 
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This image was taken by Navcam: Left B (NAV_LEFT_B) onboard NASA's Mars rover Curiosity on Sol 1301 (2016-04-03 23:02:38 UTC).
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1302 (2016-04-05 00:28:00 UTC). 
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1302 (2016-04-04 17:39:39 UTC). 
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1302 (2016-04-04 17:39:39 UTC). 
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1302 (2016-04-05 00:31:49 UTC). 
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1302 (2016-04-05 00:36:28 UTC). 
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1302 (2016-04-05 00:37:07 UTC). 
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1302 (2016-04-05 00:46:09 UTC). 
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1302 (2016-04-05 00:47:26 UTC). 
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1302 (2016-04-05 00:59:03 UTC). 
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1302 (2016-04-05 01:02:02 UTC). 
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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 1303 (2016-04-05 20:42:55 UTC). 
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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 1303 (2016-04-05 22:03:43 UTC). 
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1303 (2016-04-06 00:46:16 UTC). 
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This image was taken by Front Hazcam: Left B (FHAZ_LEFT_B) onboard NASA's Mars rover Curiosity on Sol 1304 (2016-04-06 23:43:29 UTC). 
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1305 (2016-04-07 23:56:13 UTC). 
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1305 (2016-04-08 01:28:07 UTC). 
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1306 (2016-04-08 19:54:32 UTC). 
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This image was taken by Navcam: Right B (NAV_RIGHT_B) onboard NASA's Mars rover Curiosity on Sol 1306 (2016-04-08 23:50:03 UTC). 
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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 1309 (2016-04-12 01:19:18 UTC).
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1309 (2016-04-12 01:19:18 UTC). 
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1309 (2016-04-12 04:57:00 UTC). 
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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 1311 (2016-04-14 03:39:24 UTC). 
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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 1311 (2016-04-14 03:37:48 UTC).
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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 1312 (2016-04-15 03:33:27 UTC). 
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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 1312 (2016-04-15 04:33:29 UTC). 
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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 1312 (2016-04-15 04:34:08 UTC). 
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NASA's Mars rover Curiosity acquired this image using its Mars Hand Lens Imager (MAHLI), located on the turret at the end of the rover's robotic arm, on April 16, 2016, Sol 1313 of the Mars Science Laboratory Mission, at 08:01:01 UTC.
When this image was obtained, the focus motor count position was 13013. This number indicates the internal position of the MAHLI lens at the time the image was acquired. This count also tells whether the dust cover was open or closed. Values between 0 and 6000 mean the dust cover was closed; values between 12500 and 16000 occur when the cover is open. For close-up images, the motor count can in some cases be used to estimate the distance between the MAHLI lens and target. For example, in-focus images obtained with the dust cover open for which the lens was 2.5 cm from the target have a motor count near 15270. If the lens is 5 cm from the target, the motor count is near 14360; if 7 cm, 13980; 10 cm, 13635; 15 cm, 13325; 20 cm, 13155; 25 cm, 13050; 30 cm, 12970. These correspond to image scales, in micrometers per pixel, of about 16, 25, 32, 42, 60, 77, 95, and 113.
Most images acquired by MAHLI in daylight use the sun as an illumination source. However, in some cases, MAHLI's two groups of white light LEDs and one group of longwave ultraviolet (UV) LEDs might be used to illuminate targets. When Curiosity acquired this image, the group 1 white light LEDs were off, the group 2 white light LEDs were off, and the ultraviolet (UV) LEDS were off. 
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NASA's Mars rover Curiosity acquired this image using its Mars Hand Lens Imager (MAHLI), located on the turret at the end of the rover's robotic arm, on April 16, 2016, Sol 1313 of the Mars Science Laboratory Mission, at 08:20:49 UTC.
When this image was obtained, the focus motor count position was 12582. This number indicates the internal position of the MAHLI lens at the time the image was acquired. This count also tells whether the dust cover was open or closed. Values between 0 and 6000 mean the dust cover was closed; values between 12500 and 16000 occur when the cover is open. For close-up images, the motor count can in some cases be used to estimate the distance between the MAHLI lens and target. For example, in-focus images obtained with the dust cover open for which the lens was 2.5 cm from the target have a motor count near 15270. If the lens is 5 cm from the target, the motor count is near 14360; if 7 cm, 13980; 10 cm, 13635; 15 cm, 13325; 20 cm, 13155; 25 cm, 13050; 30 cm, 12970. These correspond to image scales, in micrometers per pixel, of about 16, 25, 32, 42, 60, 77, 95, and 113.
Most images acquired by MAHLI in daylight use the sun as an illumination source. However, in some cases, MAHLI's two groups of white light LEDs and one group of longwave ultraviolet (UV) LEDs might be used to illuminate targets. When Curiosity acquired this image, the group 1 white light LEDs were off, the group 2 white light LEDs were off, and the ultraviolet (UV) LEDS were off. 
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This image was taken by Navcam: Left B (NAV_LEFT_B) onboard NASA's Mars rover Curiosity on Sol 1313 (2016-04-16 07:58:31 UTC). 
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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 1314 (2016-04-17 06:01:42 UTC). 
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1315 (2016-04-18 05:38:50 UTC). 
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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 1316 (2016-04-19 07:04:29 UTC). 
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This image was taken by Navcam: Left B (NAV_LEFT_B) onboard NASA's Mars rover Curiosity on Sol 1316 (2016-04-19 09:05:42 UTC). 
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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 1317 (2016-04-20 10:45:26 UTC). 
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1317 (2016-04-20 10:45:55 UTC). 
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Fotos: NASA

Tags: Raumfahrt 

1217 Views

Sonntag, 12. Juni 2016 - 12:20 Uhr

Astronomie - ELVE (Emissions of Light and Very Low Frequency Perturbations due to Electromagnetic Pulse Sources)

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DONUT OF LIGHT OVER COLORADO: It was faint, brief, and enormous. On June 8th, amateur astronomer Thomas Ashcraft photographed a 300 km-wide donut of light over a thunderstorm in southeast Colorado:

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Video hier: https://vimeo.com/169885841

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"It only lasted about a millisecond," says Ashcraft, "but it was definitely there."
This is an example of an ELVE (Emissions of Light and Very Low Frequency Perturbations due to Electromagnetic Pulse Sources). First seen by cameras on the space shuttle in 1990, ELVEs appear when a pulse of electromagnetic radiation from lightning propagates up toward space and hits the base of Earth's ionosphere. A faint ring of light marks the broad 'spot' where the EMP hits.
ELVES often appear alongside red sprites. Indeed, Ashcraft's camera caught a cluster of sprites leaping straight up through the middle of the donut. "Play the complete video to see the sprites," says Ashcraft.
ELVEs are elusive--and that's an understatement. Blinking in and out of existance in only 1/1000th of a second, they are completely invisible to the human eye. For comparison, red sprites tend to last for hundredths of a second and regular lightning can scintillate for a second or more. To catch an ELVE, a high-speed video camera is required. Stay tuned for more captures as thunderstorm season unfolds.
Quelle: Spacewather

Tags: Astronomie 

1315 Views

Sonntag, 12. Juni 2016 - 10:15 Uhr

Astronomie - Hubble entdeckt geheimnisvolle Einsiedler Galaxie UGC 4879

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The drizzle of stars scattered across this image forms a galaxy known as UGC 4879. UGC 4879 is an irregular dwarf galaxy — as the name suggests, galaxies of this type are a little smaller and messier than their cosmic cousins, lacking the majestic swirl of a spiral or the coherence of an elliptical.
This galaxy is also very isolated. There are about 2.3 million light years between UGC 4879 and its closest neighbor, Leo A, which is about the same distance as that between the Andromeda Galaxy and the Milky Way.
This galaxy’s isolation means that it has not interacted with any surrounding galaxies, making it an ideal laboratory for studying star formation uncomplicated by interactions with other galaxies. Studies of UGC 4879 have revealed a significant amount of star formation in the first 4 billion years after the Big Bang, followed by a strange 9-billion-year lull in star formation that ended 1 billion years ago by a more recent re-ignition. The reason for this behavior, however, remains mysterious, and the solitary galaxy continues to provide ample study material for astronomers looking to understand the complex mysteries of star birth throughout the universe.
Quelle: NASA

Tags: Astronomie 

1375 Views

Sonntag, 12. Juni 2016 - 10:00 Uhr

Science - Neues topologisches Halbmetall

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These graphs, known as Riemann surfaces, describe the energy-momentum relationships of electrons in the surfaces of exotic new materials called topological semimetals.
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Discovered just five years ago, topological semimetals are materials with unusual physical properties that could make them useful for future electronics. In the latest issue of Nature Physics, MIT researchers report a new theoretical characterization of topological semimetals' electrical properties that accurately describes all known topological semimetals and predicts several new ones.
Guided by their model, the researchers also describe the chemical formula and crystal structure of a new topological semimetal that, they reason, should exhibit electrical characteristics never seen before. "Generally, the properties of a material are sensitive to many external perturbations," says Liang Fu, an assistant professor of physics at MIT and senior author on the new paper.
"What's special about these topological materials is they have some very robust properties that are insensitive to these perturbations. That's attractive because it makes theory very powerful in predicting materials, which is rare in condensed-matter physics. Here, we know how to distill or extract the most essential properties, these topological properties, so our methods can be approximate, but our results will be exact."
Semimetals are somewhat like semiconductors, which are at the core of all modern electronics. Electrons in a semiconductor can be in either the "valence band," in which they're attached to particular atoms, or the "conduction band," in which they're free to flow through the material as an electrical current. Switching between conductive and nonconductive states is what enables semiconductors to instantiate the logic of binary computation.
Bumping an electron from the valence band into the conduction band requires energy, and the energy differential between the two bands is known as the "band gap." In a semimetal - such as the much-studied carbon sheets known as graphene - the band gap is zero. In principle, that means that semimetal transistors could switch faster, at lower powers, than semiconductor transistors do.
Parking-garage graphs
The term "topological" is a little more oblique. Topology is a branch of mathematics that treats geometry at a high level of abstraction. Topologically, any object with one hole in it - a coffee cup, a donut, a garden hose - is equivalent to any other. But no amount of deformation can turn a donut into an object with two holes, or none, so two-holed and no-holed objects constitute their own topological classes.
In a topological semimetal, "topological" doesn't describe the geometry of the material itself; it describes the graph of the relationship between the energy and the momentum of electrons in the material's surface. Physical perturbations of the material can warp that graph, in the same sense that a donut can be warped into a garden hose, but the material's electrical properties will remain the same. That's what Fu means when he says, "Our methods can be approximate, but our results will be exact."
Fu and his colleagues - joint first authors Chen Fang and Ling Lu, both of whom were MIT postdocs and are now associate professors at the Institute of Physics in Beijing; and Junwei Liu, a postdoc at MIT's Materials Processing Center - showed that the momentum-energy relationships of electrons in the surface of a topological semimetal can be described using mathematical constructs called Riemann surfaces.
Widely used in the branch of math known as complex analysis, which deals with functions that involve the square root of -1, or i, Riemann surfaces are graphs that tend to look like flat planes twisted into spirals.
"What makes a Riemann surface special is that it's like a parking-garage graph," Fu says. "In a parking garage, if you go around in a circle, you end up one floor up or one floor down. This is exactly what happens for the surface states of topological semimetals. If you move around in momentum space, you find that the energy increases, so there's this winding."
The researchers showed that a certain class of Riemann surfaces accurately described the momentum-energy relationship in known topological semimetals. But the class also included surfaces that corresponded to electrical characteristics not previously seen in nature.
Cross sections
The momentum-energy graph of electrons in the surface of a topological semimetal is three dimensional: two dimensions for momentum, one dimension for energy. If you take a two-dimensional cross section of the graph - equivalent to holding the energy constant - you get all the possible momenta that electrons can have at that energy. The graph of those momenta consists of curves, known as Fermi arcs.
The researchers' model predicted topological semimetals in which the ends of two Fermi arcs would join at an angle or cross each other in a way that was previously unseen. Through a combination of intuition and simulation, Fang and Liu identified a material - a combination of strontium, indium, calcium, and oxygen - that, according to their theory, should exhibit such exotic Fermi arcs.
What uses, if any, these Fermi arcs may have is not clear. But topographical semimetals have such tantalizing electrical properties that they're worth understanding better.
Of his group's new work, however, Fu acknowledges that for him, "the appeal is its mathematical beauty - and the fact that this mathematical beauty can be found in real materials."
Quelle: SD

Tags: Science 

1358 Views

Sonntag, 12. Juni 2016 - 09:45 Uhr

Planet Erde - Die Zusammensetzung und Temperatur des Erdinneren

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The schematic plot of VP and VS anomaly caused by thermal anomaly under spin transition of iron in ferropericalse. Image courtesy Science China Press.

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The composition and temperature of the Earth's interior are fundamental for us to understand the Earth' interior and his dynamics. Because of the impossibility to access directly most areas of the Earth's interior, the combination of the elasticity of minerals at high temperature and pressure (PT) and the seismic results becomes one of most practical ways to constrain the temperature and chemical composition of Earth's interior.
This is done by answering what kinds of aggregates of minerals have the sound velocities and densities of Earth's interior. Therefore the elasticity of minerals at high PT is crucial for us to translate the seismic sound velocity into the composition and temperature.
However, obtaining elasticity of minerals at high PT is highly challenging for experimental measurements and extremely expensive using the first-principles calculations. Wu and Wentzcovitch (2011) developed a new method, which reduces the computational loads to one-tenth of the traditional method.
The method has been successfully applied to many minerals, whose elastic data are ideal in constraining the composition and temperature and understanding the velocity structure of the lower mantle. Zhongqing Wu and Wenzhong Wang, two scientists at University of Science and Technology of China, review recently the relevant advance.
The traditional method requires vibration density of state (DOS) of ~ 100 configurations with various kinds of strains and volumes. By analyzing the relations between volume dependence of and strain dependence of lattice vibration, Wu found how to get the knowledge of strain dependence of lattice vibration needed in calculating the elasticity from the volume dependence of vibration, which avoids the vibration DOS for the configurations under strains.
Therefore the numbers of the vibrational DOS need to be calculated is reduced to ~10 from ~100 in the traditional method. It is clear that the computational and manual loads of the new method are only less than tenth of the traditional method. The elastic data show that the new method has the comparable precise as the traditional method.
The effect of spin transition of iron on the properties of ferropericalse has been conducted extensively in the last decade. Taking advantage of the new method, Wu et al for the first time obtained the elastic data of ferropericlase and found that the spin transition can produce some visible features in seismic tomography and some reported seismic tomography results show the features in consistence with the spin crossover. The works open the possibility to take advantage directly of the spin crossover to promote our understanding to the lower mantle.
In general, the bulk modulus of the materials decreases slowly with increasing temperature. The spin transition leads to an unusual effect that the bulk modulus of ferropericlase increases quickly with increasing temperature at certain temperature range. The effect is so significant that the bulk modulus of the lower mantle can increase with increasing temperature at some depths even the lower mantle has only ~15 wt% Fp.
Therefore the temperature effect of the bulk modulus and of the shear modulus of the lower mantle cancels out each other and VP of the lower mantle become insensitive to the temperature at certain range of the depths (~1750 km). VP anomaly caused by thermal anomaly should be much smaller at the depth of ~1750 km than those at the adjoined depths, namely, the structure of VP looks like have a disruption.
Geodynamic simulation show that spin transition play a critical role for structure feature of the large low shear velocity provinces in the lower mantle because of anomalous effect of spin transition on the thermodynamic properties of ferropericalse. Therefore the spin transition of iron in ferropericalse in the lower mantle has been suggested by three main branches of geophysics: mineral physics, seismology and geodynamics.
Using the obtained elastic data, Wu constrained the composition of the lower mantle and show that the content of Fp locates between the pyrolite and chondritic model, two main composition models of the mantle and any composition well constrained by seismic model has a sufficient amount of ferropericalse to show the positive temperature dependence of the bulk sound velocity but is not sufficient to exhibit the positive temperature dependence of the compressional wave velocity at the middle lower mantle.
Anticorrelation between the bulk sound velocity and the shear velocity without involving any composition variation is a robust feature at the middle lower mantle.
Quelle: SD

Tags: Planet Erde 

1436 Views

Sonntag, 12. Juni 2016 - 09:30 Uhr

Raumfahrt - Start von Delta-IV Heavy mit NROL-37 Satelliten

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30.05.2016
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Delta IV Heavy to Launch NROL-37

Delta IV NROL-37 Launch ArtworkMay 27, 2016, Update: The NROL-37 Delta IV launch is delayed at the request of the customer. The NROL-37 spacecraft and launch vehicle are secure on Space Launch Complex 37. 
Rocket/Payload: A United Launch Alliance Delta IV Heavy will launch the NROL-37 mission for the National Reconnaissance Office (NRO).
Date/Site/Launch Time: Space Launch Complex (SLC)-37, at Cape Canaveral Air Force Station, Florida.
Mission Description: The mission will be launched for the National Reconnaissance Office in support of national defense.  
Launch Notes: NROL-37 will be the 32nd Delta IV mission since the vehicle’s inaugural launch in 2002, and the 10th NRO mission to launch on Delta IV.
Quelle: ULA
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NRO delays launch of Delta IV Heavy

Next Saturday's planned launch of a heavy-lift Delta IV rocket from Cape Canaveral has been postponed.
United Launch Alliance on Friday said the mission was delayed at the request of the National Reconnaissance Office, whose classified payload will launch atop the Delta IV Heavy.
No new target date was announced for the mission labeled NROL-37.
"The NROL-37 spacecraft and launch vehicle are secure on Space Launch Complex 37," ULA said in a statement.
ULA simultaneously is preparing for a June 24 launch of an Atlas V rocket and Navy communications satellite from Launch Complex 41.
Falcon booster returning to Port
For the third time, a ship carrying the first stage of a SpaceX Falcon 9 rocket is steaming back to Port Canaveral.
After its 5:39 p.m. Friday launch from Cape Canaveral with the Thaicom 8 communications satellite, the rocket stuck its landing on the modified barge more than 400 miles down range.
SpaceX CEO Elon Musk said there was a risk the booster could tip over following its relatively high-speed touchdown, but it didn't. Crews boarded the "Of Course I Love You" ship to secure the stage and begin sailing it home.
The journey typically takes three or four days, depending on the distance back to port and weather conditions. At Port Canaveral, a crane will offload the rocket stage so it can be transported horizontally to SpaceX's hangar at the base of pad 39A at Kennedy Space Center.
The stage was the third in a row that SpaceX has landed, and fourth overall. The first, in December, landed on land at Cape Canaveral while the last three have been ocean landings.
Quelle: Florida Today
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Update: 3.06.2016
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Upcoming Delta 4-Heavy launch back on track after payload-related delay

CAPE CANAVERAL — A new launch date has been established — June 9 — for the Delta 4-Heavy rocket to carry a classified satellite into space for U.S. national security needs.
Liftoff of the United Launch Alliance rocket will be possible during a five-hour period stretching from 1:30 to 6:30 p.m. EDT (1730-2230 GMT). The actual launch window is hidden within that unclassified period.
Readiness of the payload delayed the flight from its earlier target of June 4. But given the secretive nature of the spacecraft, no details were publicly revealed about what specifically triggered the slip.
The satellite and rocket are stacked atop Complex 37 at Cape Canaveral Air Force Station for the mission.
“The spacecraft, launch vehicle and support systems are ready to support launch,” United Launch Alliance said in a statement to the press today.
The launch is being performed for the U.S. National Reconnaissance Office, the agency responsible for the country’s spy satellite fleet. The NRO is a joint organization between the Department of Defense and Intelligence Community.
The identity of the satellite launching aboard the Delta 4-Heavy is top-secret. The launch is known as NROL-37.
It is the first of five national security space launches scheduled over the next four months, three aboard Delta 4 rockets and two on Atlas 5.
After the Heavy, the Navy’s MUOS 5 communications satellite and the NROL-61 mission are planned on back-to-back Atlas 5 launches, then a pair of Delta 4s will launch the second set of Geosynchronous Space Situational Awareness Program, or GSSAP, satellites for U.S. Strategic Command followed by the Air Force’s Wideband Global SATCOM 8 communications spacecraft.
Quelle: SN
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Update: 5.06.2016
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Launch week: ULA's Delta IV Heavy set to launch for NRO

United Launch Alliance is poised to launch its first mission since March, with a heavy-lift Delta IV rocket targeting an afternoon launch Thursday, June 9, from Cape Canaveral Air Force Station.
Liftoff from Launch Complex 37 is planned between 1:30 p.m. and 6:35 p.m. A more precise launch window will be released before then.
The classified National Reconnaissance Office mission was delayed five days due to an unspecified issue with the payload. ULA on June 2 confirmed the launch was "go" to proceed a week later.
"The spacecraft, launch vehicle and support systems are ready to support launch," the company said in a statement.
The launch will be the 32nd by a Delta IV rocket and ninth by a Delta IV Heavy, whose three core boosters generate 2.1 million pounds of thrust at liftoff.
Quelle: Florida Today
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Update: 7.06.2016
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Weather 40 percent ‘go’ for Delta 4-Heavy

The sun rises on Delta 4-Heavy for NROL-15 launch in 2012. Credit: Walter Scriptunas II / Scriptunas Images
CAPE CANAVERAL — After tropical weather passes through Florida to start the week, meteorologists say there is a 40 percent chance of acceptable conditions for the United Launch Alliance Delta 4-Heavy rocket to fly Thursday from Cape Canaveral with a reconnaissance satellite payload for the U.S. government.
Tropical Storm Colin, which formed Sunday over the southern Gulf of Mexico, will make its way northeastward today, bringing its center ashore in the Big Bend area of Florida. Along the Space Coast, heavy rains are expected through Tuesday and a tropical storm warning is in effect for the beaches.
The Delta 4-Heavy rocket and its classified National Reconnaissance Office payload are safe and secure within the protective gantry at Complex 37.
“Weather will improve Wednesday, but Thursday a trough to the south will migrate north over the Space Coast causing a risk of showers and thunderstorms beginning as early as noon and continuing into the afternoon,” Air Force launch meteorologists reported today.
“Anvils from inland storms will also migrate toward the Space Coast. The primary concerns for launch are anvil clouds, cumulus clouds and lightning.”
Thursday’s liftoff will happen some time between 1:30 and 6:30 p.m. EDT (1730-2230 GMT).
Winds will be easterly at 12 gusting to 18 knots and temperatures will be in the mid-80s F.
If the launch is scrubbed, another flight opportunity will be available Saturday. The outlook improves to 80 percent “go” odds then.
“In the event of a 48-hour delay, weather improves significantly as the boundary moves south and dryer air aloft moves in. The primary concern for a 48-hour delay is thick cloud,” launch forecasters said.
Quelle: SN
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Update: 9.06.2016
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Mammoth Eavesdropping Satellite Set for Launch Thursday Atop Delta-IV Heavy

Armed and with his identity protected, this swordsman guards the American Flag
behind a shield marked 37 in Roman numerals. Image Credit: NRO
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The biggest spacecraft in the world—a top secret $1.7 billion National Reconnaissance Office (NRO) Mentor/Advanced Orion eavesdropping satellite—is ready for launch from Cape Canaveral AFS as soon as June 9 at 1:59 pm EDT, on board the most powerful operational rocket in the world, a$375 million United Launch Alliance (ULA) Delta IV Heavy.
Carrying a mammoth eavesdropping antenna spanning 330 feet, the Mentors “are the largest satellites ever launched,” said Air Force 4-star Gen. Bruce Carlson (ret), who headed NRO from 2009-2012.
NRO-37The nearly 6-ton NRO 37 Mentor/Advanced Orion spacecraft being launched is a Crown Jewel of America’s top secret intelligence satellite operations. This is because of its importance to national security from its signals and electronic intelligence intercepts for the National Security Agency (NSA); Central Intelligence Agency (CIA); Defense Intelligence Agency (DIA); and for Army, Navy, Air Force, and National Command Authority intelligence operations.
Local and national news media will briefly cover (or not cover) the NRO 37 mission as if it is a routine shot. But this over $2 billion mission is far from routine.
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The Mentor/Advanced Orion spacecraft provides unique and vitally important intelligence by listening to Middle Eastern Adversaries, such as ISIS, and political and military officials in China, North Korea, Russia, and other countries.
The satellite will also listen-in to telemetry from foreign missile tests, especially key intelligence from North Korea, China, and Russia, which are all developing multiple new missiles with which to threaten the U.S. on land, sea, and in the air.
The NRO long ago developed the ability to listen to Chinese and Soviet/Russian leaders in their offices and cars. But as technology has advanced such eavesdropping has become far more complex. Much of the intelligence received is coded, requiring extensive efforts at NSA to break it.
In addition to its intelligence data, the NRO Mentor and ULA/USAF Delta-IV Heavy programs fund hundreds of ULA jobs across the U.S. and at the Cape’s 45th Space Wing. In fact the Delta-IV Heavy rocket was developed primarily for launching advanced Mentor/Orion spacecraft directly into geosynchronous orbit. It also launches advanced Crystal KH-11 type digital imaging satellites into medium altitude polar orbits.
Locally, the Harris Corp. in Melbourne, Fla., has received hundreds of millions of dollars in NRO funding for the football field-sized dish antenna on each Mentor/Advanced Orion spacecraft. So far eight Orion and Advanced Orion Mentors have been launched carrying the huge Harris antennas. These Harris antennas involve some of the country’s most advanced highly protected technologies.
The prime contractor for previous versions of the Advanced Orion/Mentor spacecraft was TRW/Northrop Grumman Corp. (NGC), and it is likely NGC remains the lead contractor.
The weather for a Thursday launch attempt is predicted to be 60 percent unfavorable, with clouds and thunderstorms a possibility throughout the day. If weather or technical issues force tomorrow’s launch to be scrubbed, the next opportunity to launch the NRO mission will come Saturday, June 11.
The 48-hour turnaround requirement is caused by Eastern Test Range requirements to support the “Return to Flight” at the Wallops Flight Center of the Orbital ATK Antares rocket, which now sports two new Energomash RD-181 engines.
The Delta-IV Heavy NRO 37 mission will lift off on 2 million pounds of thrust, generated from its three RS-68A engines in the triple core launcher.
They will propel the Delta-IV Heavy off Launch Complex 37B on a trajectory that will place the satellite directly into geosynchronous orbit. That location remains secret, but it will join three other Mentor/Advanced Orions launched by Delta-IV Heavies since 2009.
At liftoff Each oxygen/hydrogen powered RS-68A will produce 705,000 lbs thrust—30 percent more than each Space Shuttle Main Engine generated.
The launch milestone chart below shows the approximate timing of NRO-37 ascent milestones, including the three burns by the Delta IV Heavy’s upper stage powered by a 25,000 lb-thrust RL-10-B-2 engine.
The exact ascent milestones must remain secret to avoid Russian and Chinese precision tracking. But the chart was originally prepared for the Initial Delta IV Heavy flight test with the initial RS-68 versions. It uses a two burn upper stage test profile.
Calculations by world renowned military space analyst Ted Molczan in Canada show the expected altitudes for each upper stage maneuver:
—Initial second stage engine cutoff is predicted to result in a 190 x 244 Km. (118 x 151 mi.) orbit .
—Second upper stage cutoff orbit is predicted by Molczan to be in orbit at 212 x 35,809 km. (132 x 22,250 mi.).
—Third upper stage burn is predicted to achieve a 35,746 (22,211 mi.) geosynchronous orbit.
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Quelle: AS
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Update: 19.40 MESZ
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Launch LIVE-Frams:
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20.15 MESZ
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Start verschoben wegen Wetterlage...
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Update: 23.25 MESZ
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Update: 10.06.2016
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Delta IV Heavy to Launch NROL-37
Delta IV NROL-37 Launch ArtworkCape Canaveral Air Force Station, Fla. (June 9, 2016) - The ULA Delta IV NROL-37 launch scrubbed for the day due to violation of multiple launch weather criteria. The Delta IV NROL-37 is scheduled to lift off on Saturday, June 11 at 1:51 p.m. from Space Launch Complex 37 at Cape Canaveral Air Force Station in Florida..
Rocket/Payload:  A United Launch Alliance Delta IV Heavy will launch the NROL-37 mission for the National Reconnaissance Office (NRO).
Date/Site/Launch Time: Saturday, June 11, 2016, from Space Launch Complex (SLC)-37 at Cape Canaveral Air Force Station, Florida. Launch is planned for 1:51 p.m. EDT (17:51 GMT).
Webcast: The live broadcast will begin at 1:31 p.m. EDT.
Launch Notes: NROL-37 will be the 32nd Delta IV mission since the vehicle’s inaugural launch in 2002, and the 10th NRO mission to launch on Delta IV.
Mission Description: The mission will be launched for the National Reconnaissance Office in support of national defense.
Launch Updates: To keep up to speed with updates to the launch countdown, dial the ULA launch hotline at 1-877-852-4321 or join the conversation at www.facebook.com/ulalaunch, twitter.com/ulalaunch and instagram.com/ulalaunch; hashtags #NROL37 and #DeltaIV.
Quelle: ULA
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Update: 11.06.2016 / 16.40 MESZ
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Quelle: ULA
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Update: 19.15 MESZ
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LIFT OFF
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Quelle: ULA
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Update: 12.06.2016
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Rocket with secret cargo blasts off from Florida

A towering United Launch Alliance Delta 4-Heavy rocket believed to be carrying a National Reconnaissance Office electronic eavesdropping satellite climbed away from Cape Canaveral Saturday, putting on a spectacular weekend show as it streaked toward space on a blacked-out mission.
Running two days late because of stormy weather, the heavy-lift Delta 4 thundered to life with a brilliant rush of fiery exhaust at 1:51 p.m. EDT (GMT-4) as its three Common Booster Core engines ignited and throttled up to full power.
An instant later, generating a combined 2.1 million pounds of thrust, the huge rocket began climbing away from complex 37 at the Cape Canaveral Air Force Station. It was only the ninth launch of a Delta 4-Heavy, the most powerful operational rocket in the U.S. inventory, and the first since December 2014.
Burning three tons of liquid oxygen and hydrogen fuel per second, the rocket quickly lost weight and accelerated, arcing away to the east over the Atlantic Ocean on a trajectory typically used to put satellites in high "geosynchronous" orbits where they circle the globe in lockstep with Earth's rotation.
Liftoff came two days after a launch scrub Thursday because of extensive showers, thick clouds and electrical activity across southern Florida. More of the same was expected Saturday, but no storms were in the area at launch time, and mission managers cleared the 1.6-million-pound rocket for flight.
Four minutes after liftoff, now well out of the denser lower atmosphere, the Delta 4's two strap-on Common Booster Core engines throttled back and shut down. The side boosters then were jettisoned and the Delta 4 continued the ascent on the power of its central CBC engine. A minute and a half later, that engine shut down as planned and the stage fell away.
The rocket's second stage engine, an Aerojet Rocketdyne RL10B2, ignited seconds later and the nose cone fairing protecting the satellite payload was jettisoned as planned.
But as usual with launchings involving classified payloads, United Launch Alliance ended its mission commentary at that point "at the request of our customer," and the rest of the Delta 4's ascent was carried out in secrecy.
No details about the rocket's payload were released by the Air Force or the National Reconnaissance Office.
But Ted Molzcan, a respected amateur satellite analyst who coordinates worldwide observations of military and civilian spacecraft, believes it likely was a Mentor signals intelligence satellite equipped with a huge, unfolding mesh antenna that can pull in all manner of electronic data and communications.
"If the NRO is the customer and it's a Delta 4-Heavy out of Florida, then all of the precedents have been heavy signals intelligence-type satellites," Molczan told CBS News. "One of the common code names that people use that, I guess, leaked out some years ago is Mentor. Sometimes it's also called Advanced Orion."
But that's only an educated guess, he said.
"Until you see where it actually goes and what it does, you can't totally rule out the possibility that it'll be something different," he said. "But I think it's a pretty good bet that's what it is."
Matthew Aid, author of "Intel Wars: The Secret History of the Fight Against Terror" and "The Secret Sentry," a history of the National Security Agency, said the six-ton Mentor satellites -- if, in fact, one was on board the Delta 4 -- feature the largest antennas ever used in space.
"Details of how Mentor satellites operate (are) highly classified, but they are known to pick up a large number of electronic signals from ships, aircraft and ground stations, as well as other satellites," he writes on his web page. "This data undergoes some processing on the Mentor satellite, is then encrypted and transmitted to American ground stations for further analysis."
In any case, Mentor satellites are relatively easy for space sleuths to track, thanks to the sunlight reflected by their huge antennas, believed by some to be more than a football field across.
"Several of the Mentors have been observed by my colleagues who are able to track these things visually and optically," Molczan said. "For geosynchronous birds, they're quite bright."
Unlike commercial communications satellites, which appear very dim and require telescopes to spot in their geosynchronous perches 22,300 miles above the equator, Mentors are within the reach of good binoculars.
"If you had a little bit bigger binoculars, like 11-by-80s, and you're in a part of the world where they're in your line of sight, then you'd be able to spot them without any difficulty at all," Molczan said.
Quelle: CBS NEWS



1823 Views

Samstag, 11. Juni 2016 - 23:00 Uhr

Astronomie - Jupiter und Mondsichel am Abendhimmel

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Nachfolgende Aufnahmen von Jupiter und Mond sind von Gesternabend über dem Odenwald aufgenommen:

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Fotos: ©-hjkc

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Und wenn es Heuteabend auch aufklaren sollte, sind Beide noch dichter zusammen wie auf nachfolgenden Astro-Karte zu sehen:

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Update: 22.55 MESZ

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Hier über Odenwald Wolken-Lücken welche am Westhimmel den Blick auf das Duo Jupiter und Mond frei gaben, auch wenn zusätzlich noch Nebelfetzen daran vorbei zogen. Für 4 Aufnahmen davon hat es gereicht...

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Fotos: ©-hjkc


Tags: Astronomie 

1464 Views

Samstag, 11. Juni 2016 - 16:00 Uhr

Raumfahrt - ISRO - Erfolgreicher Start von RLVTD-Space-Shuttle-Projekt-Update-3

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26.05.2016

Final Reusable Launch Vehicle RLV-TD will need a better body to be launched into space: ISRO
The rocket will have to be modified with a more sustainable body before it is finally launched into space. (ISRO)
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The rocket will have to be modified with a more sustainable body before it is finally launched into space.
The body of India's first ever indigenously built reusable space shuttle - the Reusable Launch Vehicle - Technology Demonstrator (RLV-TD) - will need to be made of better material to enable it to be launched into space, said director of Vikram Sarabhai Space Centre (VSSC), K Sivan, on Wednesday.
Indian Space Research Organisation (ISRO) successfully test launched RLV-TD on Monday from Satish Dhawan Space Centre (SDSC) in Sriharikota island of Andhra Pradesh.
Addressing the media on Wednesday after the feat, Sivan said the rocket will have to be modified with a more sustainable body before it is finally launched into space.
"The aluminum material, after 150 degrees Celsius, it will become dilute. Steel, it will become dilute at 500 degrees Celsius. You just imagine what will happen to a material if it is at 2,000 degrees Celsius. It will evaporate. So we need a protection system against that one and we need a material which is working in the high temperature. That is another thing. We need autonomous mission management, another thing," Sivan said in Chennai.
The VSSC director also suggested ways to make the vehicle more cost-effective.
"80% of the cost of the rocket and of the materials that cost, only 15-20% are consumables like propellant. Suppose, in the rocket, 80% of the rocket, if we recover 80% of the rocket, that means 80% of the money we can recover. That is simple technology. That means every time only 20% of the cost will be required to launch a satellite," added Sivan.
The test launch was intended to enable scientists to gather data on autonomous landing, hypersonic speed and more.
It's success puts India on an elite list of space-faring nations, including the United States, Japan and Russia, which have been using their own RLVs for years.
Quelle: dna
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Update: 11.06.2016
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India Slowly Becoming Space Exploration Powerhouse

India successfully launched an unmanned mini prototype space shuttle joining the world race to develop the first low-cost reusable spacecraft.
On May 23, India successfully launched an unmanned mini prototype space shuttle called the Reusable Launch Vehicle-Technology Demonstrator (RLV-TD), joining the world race to develop the first low-cost reusable spacecraft.
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According to BBC India, the 22-foot (7m) scale model took off from Andhra Pradesh and was expected to fly about 43 miles into the atmosphere before coming down to Earth into the Bay of Bengal.
According to  Indian Space Research Organisation’s (ISRO) announcement, in this successful experimental mission, the HS9 solid rocket booster carrying RLV-TD lifted off from the First Launch Pad at Satish Dhawan Space Centre, Sriharikota at 07:00hr IST.  After a successful flight of just over 90 seconds, burn out occurred, following which both HS9 and RLV-TD (mounted on its top,) coasted to a height of about 34 miles (56 km). At that height, RLV-TD separated from HS9 booster and further ascended to a height of about 40 miles (65km).
From that peak altitude of  just over 40 miles, RLV-TD began its descent followed by atmospheric re-entry at around Mach 5 (five times the speed of sound). The shuttle’s Navigation, Guidance and Control system accurately steered the vehicle during this phase for a safe descent.
“After successfully surviving a high temperatures of re-entry with the help of its Thermal Protection System (TPS), RLV-TD successfully glided down to the defined landing spot over the Bay of Bengal, at a distance of about 450 km [280 miles] from Sriharikota, completing its mission,” The Indian Space Research Organization (ISRO) announced  May 23.
The vehicle was successfully tracked during its flight from ground stations at Sriharikota and a shipborne terminal. Total flight duration from launch to the landing of this mission of the delta-winged RLV-TD lasted for about 770 seconds.
Despite operating with a budget of $1 billion—five percent of NASA’s $17.6 billion annual budget—ISRO has launched a number of successful space exploration initiatives over the last seven decades. Most notably, in September 2014, ISRO launched an orbiter on to Mars, making it the fourth agency to do so after the United States, the Soviet Union, and the European Union. ISRO accomplished this on a mere $75 million budget—just 11 percent of what it cost NASA
Quelle: india

Tags: Raumfahrt 

1520 Views


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