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Sonntag, 16. August 2015 - 22:45 Uhr

Raumfahrt-History - 1962: X-20 DYNA-SOAR SPACE VEHICLE

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The Dyna-Soar design contract was awarded to Boeing on Nov. 9, 1959, and on June 19, 1962, the Dyna-Soar was designated the X-20.
The Dyna-Soar, designed to be a 35.5-foot (10.8-meter) piloted reusable space vehicle, had a sharply swept delta 20.4-foot-span (62-meter-span) wing and a graphite and zirconia composite nose cap and used three retractable struts for landing. Eleven manned flights were to be launched from Cape Canaveral, Fla., starting in November 1964. Dyna-Soar’s first orbital flight was tentatively scheduled for early 1965.
The X-20 reached the mockup stage. $410 million had been spent on its development, and a cadre of astronauts was training to fly it. However, the U.S. government canceled the program on Dec. 10, 1963, because Dyna-Soar had no viable military mission and was too expensive for a research vehicle. Congress diverted the X-20 funding to the Manned Orbiting Laboratory, which used McDonnell-built Gemini capsules. The partially completed X-20 prototype and the mockup were scrapped as well as initial tooling set up for a production line for 10 space planes.
In 1961, the U.S. Air Force had contracted with McDonnell Aircraft to build six experimental aerodynamic/elastic structures environment test vehicles that roughly resembled the Dyna-Soar. The scaled-down test vehicles were 5.7 feet (1.7 meters) long and used Douglas-built Thor or Thor-Delta boosters, which in turn used engines built by North American’s Rocketdyne division. The program was very successful and demonstrated that winged reentry vehicles could traverse the upper atmosphere.
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Quelle: Boeing

Tags: Raumfahrt 

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Sonntag, 16. August 2015 - 19:00 Uhr

Astronomie - Ist das Universum vor Annäherung an einen Zustand der Entropie?

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It's the end of the universe as we know it, but don't worry just yet

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A team of astronomers from around the world confirmed this week what researchers have known for almost a century now: what started with the Big Bang will eventually go bust.
According to experts from the Galaxy And Mass Assembly (GAMA), the universe is only churning out half as much energy as it did 2 billion years ago, and is gradually approaching a state of entropy. The study confirmed something researchers have suspected for decades: the stars that populate countless galaxies are slowly burning themselves out.
Could that bleak scenario, although far into the future, have an impact on expectations for space travel, and other such endeavors? The question is legitimate, given that space tourism is expected to grow into a $1 billion sector over the next several years, according to the Federal Aviation Administration. Meanwhile the National Space Society estimates the industry's size could eventually swell to as high as $1 trillion.
Indeed, the GAMA research in some ways seems to have inspired science writers and science fiction rather than scientists, many of whom think the new data illustrate information that has been known for years. The new information is not, as one astrophysicist put it, "earth-shattering," nor is it likely to be an issue for at least a billion years or so, they add.
However, scientists from some of the top academic institutions across the United States agree that the new data contribute to the understanding of the universe—even if the findings are relatively old hat.
"Of course the universe is dying," said Sean Carroll, an astrophysicist at the California Institute of Technology, who authored two books on theoretical physics. He added that it was "something we've known since at least the 1920s."
In the early 20th century, scientists theorized that the universe was dying, yet only recently has that death been accurately measured. The new GAMA study is part of an effort to quantify the effects of universal deterioration.
The news comes as space exploits have dominated headlines. Recent events has included comet landings, meteor showers, the discovery of an Earth-like planet and a touchdown on Pluto—putting the mysteries of the universe squarely in the public's imagination.
The study, which was jointly led by Simon Driver and Andrew Hopkins, was an international effort that harnessed technology both on land and in space to study 200,000 galaxies and the energy they generated. Basically, it found that stars have lost roughly half their firepower over the last 2 billion years.
Yet the scientists stated the demise of all we know could best be described as a fade to black, rather than an apocalyptic end. As the International Centre for Radio Astronomy Research, where Driver is on staff, euphemistically put it, scientists are measuring "the slow death of the universe."
Driver conceived and initiated the project, and told CNBC in an interview that he prefers to say the universe is "fading," rather than dying. He said that he and his team studied the "energy released from matter" from galaxies where the light takes between some tens of millions to 2 billion years to reach the planet.
What the team produced was more and newer data that confirms the energy release by galaxies is declining. In other words, Driver said, the universe "will get consistently darker and gloomier"—although no one can estimate when, or by how much.
There is one type of cosmic body largely responsible for emitting galactic energy, and it's slowly losing steam, experts said. "Those emissions are dominated by stars," said Adam Burrows, professor in the astrophysical sciences department at Princeton University. The galaxy gas that creates these stars "is being depleted, and is not being adequately replenished."
Burrows, who used to chair the National Research Council Board on Physics and Astronomy, also chose to describe the scenario as a "gradual diminution of the brightness of the galaxies," rather than either dying or fading. Andrew Hopkins, head of research at the Australian Astronomical Observatory who jointly led the GAMA survey, chose to call it a "decline."
Daniel Akerib, a professor of particle physics and astrophysics at Stanford University, simply described the phenomenon as "expanding and cooling," adding that some of the doom and gloom appears overblown. To believe stars are in imminent danger of being extinguished "strikes me as a bit hyped, like saying that a newborn baby in its first week of life has started dying," Akerib said.
Whether the universe is dying, fading, declining or cooling, most scientists believe the endgame is too far into the future for humans to worry about. In fact, one scientist contends it could be 100 billion years out before the universe fizzles.
For perspective, the universe is just 14 billion years old, according to NASA.
"I'm not losing any sleep over this, since there are much more urgent threats to humanity from our own reckless behavior," said cosmologist Max Tegmark, a physics professor at the Massachusetts Institute of Technology and author of the book "Our Mathematical Universe."
Meanwhile, there might be more immediate challenges for the universe—and again, those too are much further on the horizon. "In 5 billion years, the sun will expand and swallow the Earth," said Driver. "In 10 billion years, our galaxy will merge with Andromeda."
In the meantime, scientists intend to keep themselves busy studying the more than 200,000 known galaxies that remain shrouded in mystery. Astronomers estimate there are more than 100 billion galaxies in the observable universe, said David Kaiser, a physics professor at MIT whose work focuses on Early-universe cosmology.
"We're starting to answer some of the questions asked by every civilization that's ever existed," said Driver. "But there's still a long way to go."
Quelle: CNBC

Tags: Astronomie 

1690 Views

Sonntag, 16. August 2015 - 15:30 Uhr

Raumfahrt-History - 1975: Venera-9 und Venera-10

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Aus dem CENAP-Archiv:

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Quelle: CENAP-Archiv


Tags: Raumfahrt 

1508 Views

Sonntag, 16. August 2015 - 10:27 Uhr

Raumfahrt - Neues IC, DoD Space Center als Nachfolger von JSPOC

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HUNTSVILLE, ALA.: The new Intelligence Community-military space operations center the military is creating may replace the long-established JSPOC, two top commanders said, but a lot has to happen first. The nascent JICSPOC — Joint, Interagency, & Coalition Space Operations Center — will start as an experiment before potentially becoming a backup to JSPOC and then one day, maybe, taking over from it.
JIPSOC is being created at the direction of Deputy Defense Secretary Robert Work. Its objective: to improve the sharing of data between the IC and the military and to help counter rising Russian and Chinese threats to US satellites and space-based systems. By bringing together intelligence agencies and foreign allies alongside the military services, it will act as a “JSPOC on steroids,” said Lt. Gen. David Mann, the chief of Army Space & Missile Defense Command.
“It really allows us to be more responsive to the warfighter and to more effectively and in a more timely manner respond to potential threats, whether it’s jamming, spoofing, whatever it may be,” Mann told reporters at the Space & Missile Defense conference here. Sure, the existing JSPOC can address these dangers too, but without having other US agencies  fully involved, he said, “you’re not fully exploiting all the other efforts that are out there.”
If the new ops center will be so much more capable than the existing one, asked one journalist, then why shouldn’t JIPSOC be the primary control site?
“It may evolve into that, over time. I don’t know. It possibly could,” Mann said, emphasizing that he can’t speak for Air Force Space Command on the matter. “This is something that was recently directed by the DepSecDef, very, very recently.”
Adm. Cecil Haney, chief of Strategic Command, added some detail. “Secretary Work mentioned the fact that ultimately it [the new JICSPOC] could be the backup for the JSPOC,” Haney said. That may or may not happen, he cautioned. For the JICSPOC, he said, “first and foremost is to figure out how we can take this operational concept, expand upon it…. so we can really protect our ability to support the warfighter.”
“The JSPOC that we have right now is a very established operations center,” he went on, so you don’t want “to stop immediately and go straight to a JICSPOC [as the primary control]. You probably have to wait for it to evolve.”
For now, the new ops center’s primary mission is experimentation, said Haney. While the new center dedicates itself to figuring out how to fight new threats to space, someone has to keep doing the existing center’s day-to-day job as (in essence) space traffic control.
“We have to be able to experiment and work our way through various vignettes,” Haney told reporters, “so we can make better investments” against threats ranging from GPS jamming to ground-based lasers. “At the same time. we still have this responsibility for being able to avoid collisions in space. [There are] agreements we have for sharing information with a number of nations, a number of commercial entities: That work still has to go on.”
Quelle: BD

Tags: Raumfahrt 

1704 Views

Sonntag, 16. August 2015 - 08:00 Uhr

UFO-Forschung-History - 1949: Wie Air Force Nacht Fotos einfängt

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Aus dem CENAP-Archiv:

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Quelle: CENAP-Archiv


Tags: UFO-Forschung 

1467 Views

Samstag, 15. August 2015 - 21:00 Uhr

Astronomie - Gaia funktioniert – ein erster Blick in die Daten Update-1

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15.08.2015

ASTEROIDS AT THE “PHOTO FINISH”
Today's Gaia blog post is contributed by Paolo Tanga, Associate Astronomer at the Observatoire de la Côte d’Azur, Nice (France).
We tend to think that a still picture, shot with an ordinary camera, represents a subject at a given time. But this is not always the case. In some situations, a picture can show the evolution in time of the depicted subject. This is the case, for example, of the well-known “photo finish” technique widely used in athletics to record the competing athletes as they cross the arrival line at the end of the race.
How does it work? Simply, the camera aims only at a vertical strip containing the finish line and repeatedly photographs it at high speed. By putting all the strips together side-by-side, one can obtain the evolution of the image of the finish line as a function of time. As weird as it may sound, the CCD camera onboard Gaia works exactly the same way – by transforming the recorded star positions into times, the finish line being a thin strip of pixels on the edge of the detector.
Let’s imagine that we are looking at a number of athletes all running at the same speed on a straight track, but each of them having started the race at a different time: in this analogy, these are the stars, which drift across the Gaia telescopes all at the same velocity – given by the constant rotation of the satellite. If Gaia observes them several times, they will always appear spaced by the same delays.
Now, let’s add to these well-behaved competitors a different type of athlete, a rebel one who's not playing by the rules, always running either much faster or much slower than the others, and not following the direction of the track lanes but drifting as he/she pleases. Each time this eccentric athlete crosses the finish line, it will be in a different position relative to the competing runners. This is how an asteroid appears to Gaia, as its motion relative to stars makes it appear always in a different position, as a function of the time at which it is observed.
This unorthodox behaviour opens up a specific category of problems when dealing with asteroid observations. The first one is predicting when – and where – Gaia will observe a given object. In practice, it’s like predicting in advance the delays of the eccentric athlete relative to the others, when on the finish line. To perform this computation, we need to have an exact knowledge of its trajectory (the orbit of the asteroid), along with the precise speed of the “ordinary” competitors (the stars). In the case of Gaia, all these pieces of information are known, but the complexity of the scanning law, which displaces the “arrival line” in non-trivial patterns, makes the task extremely delicate. Besides, there are several “finish lines” on the Gaia focal plane (at least one per CCD), so the whole geometry of the system plays a role.
The second type of problem concerns the processing of asteroid observations, especially in the case of newly detected asteroids or of asteroids whose orbit is not yet known to great precision. In fact, each time the asteroid crosses the “finish line” it will be in a different region of the sky. Only observations that are close in time can be easily linked together, as the asteroid displacement relative to its background will be small. If the observations are performed over longer time spans, the presence of several such “rebel runners” can make things extremely complex.
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These various aspects are illustrated in the following pictures. The first one (right) is a test image of the asteroid (54) Alexandra, a bright moving target. It was obtained by programming Gaia in a special imaging mode. As described before, this is a “photo finish” image. It was reconstructed by moving along the horizontal axis, which is equivalent to the observer moving in time: each pixel column represents the signal present on the “finish line” (in practice: the edge of the CCD) at a given moment. In the image, the time delay between the arrival at the finish line of the bright star and the asteroid is about 1.26 seconds. A very accurate timing of each source “arrival” is the basis of the extraordinary astrometric capabilities of Gaia.
More important, however, is the fact that in this image the predicted position of the asteroid is very close to the observed one, only a few pixels away. Given the computational difficulties involved in this process, this is an achievement with important consequences, such as the possibility to predict well enough very close “encounters” between a star and an asteroid on the plane of the sky – these are potential sources of confusion while searching for other types of anomalies (when monitoring the brightness of a star, for example). Many astronomers want to be alerted when an interesting change occurs, not when an asteroid is just passing by!
On the other hand, other astronomers (planetary scientists!) are interested in the asteroids themselves. In fact, Gaia will observe 350,000 asteroids, providing the richest sample of precise orbits and physical properties that we could dream of. Those rebel runners, containing clues about the Solar System's formation, are really interesting, and come in large quantities. Our capability to track their position is essential in the identification process.
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The case of the asteroid (4997) Ksana (above) is more difficult, and showcases the capabilities of Gaia in detecting and identifying asteroids. Because it is very faint, it may have been confused with several stars – some not even present in current catalogues – making its identification more ambiguous. The presence of a source very close to the position where the asteroid was predicted to be is very encouraging, but only a comparison of data acquired over time can provide a confirmation.
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The result is shown in (left), which represents an intermediate product of the processing itself: the preliminary positions of the sources seen by Gaia, as determined by the “Initial Data Treatment”. In these images, each point is a source and the point size is proportional to the source's brightness. Different colours represent the stars observed during five different sweeps of the same sky region, each lasting 6 seconds, by a single CCD.
The asteroid (4997) Ksana is now clearly seen moving from one sweep to the next (as indicated by the arrows). Checking the presence and motion of the object at the corresponding epoch provides a secure confirmation of its nature. A final remark: the observations are not equally spaced in time, and the closer couple of detections correspond to the source passing through the two telescopes (106 minutes apart) while the satellite rotates. A full rotation of the satellite (every 6 hours) separates the two detections in each pair.
Gaia asteroid observations will be processed using the software pipeline designed and implemented by Coordination Unit 4 of the DPAC, running at the CNES processing centre (Toulouse, France).
The data presented here are extracted from the results obtained by the Initial Data Treatment (IDT) pipeline, which was largely developed at the University of Barcelona and runs at the Data Processing Centre at ESAC.
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GAIA DISCOVERS ITS FIRST SUPERNOVA
While scanning the sky to measure the positions and movements of stars in our Galaxy, Gaia has discovered its first stellar explosion in another galaxy far, far away.
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This powerful event, now named Gaia14aaa, took place in a distant galaxy some 500 million light-years away, and was revealed via a sudden rise in the galaxy’s brightness between two Gaia observations separated by one month.
Gaia, which began its scientific work on 25 July, repeatedly scans the entire sky, so that each of the roughly one billion stars in the final catalogue will be examined an average of 70 times over the next five years.
“This kind of repeated survey comes in handy for studying the changeable nature of the sky,” comments Simon Hodgkin from the Institute of Astronomy in Cambridge, UK.
Many astronomical sources are variable: some exhibit a regular pattern, with a periodically rising and declining brightness, while others may undergo sudden and dramatic changes.
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“As Gaia goes back to each patch of the sky over and over, we have a chance to spot thousands of ‘guest stars’ on the celestial tapestry,” notes Dr Hodgkin. “These transient sources can be signposts to some of the most powerful phenomena in the Universe, like this supernova.”
Dr Hodgkin is part of Gaia’s Science Alert Team, which includes astronomers from the Universities of Cambridge, UK, and Warsaw, Poland, who are combing through the scans in search of unexpected changes.
It did not take long until they found the first ‘anomaly’ in the form of a sudden spike in the light coming from a distant galaxy, detected on 30 August. The same galaxy appeared much dimmer when Gaia first looked at it just a month before.
“We immediately thought it might be a supernova, but needed more clues to back up our claim,” explains Łukasz Wyrzykowski from the Warsaw University Astronomical Observatory, Poland.
Other powerful cosmic events may resemble a supernova in a distant galaxy, such as outbursts caused by the mass-devouring supermassive black hole at the galaxy centre.
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Supernova Gaia14aaa and its host galaxy
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However, in Gaia14aaa, the position of the bright spot of light was slightly offset from the galaxy’s core, suggesting that it was unlikely to be related to a central black hole.
So, the astronomers looked for more information in the light of this new source. Besides recording the position and brightness of stars and galaxies, Gaia also splits their light to create a spectrum. In fact, Gaia uses two prisms spanning red and blue wavelength regions to produce a low-resolution spectrum that allows astronomers to seek signatures of the various chemical elements present in the source of that light.
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COUNTING STARS WITH GAIA
This image, based on Gaia housekeeping data, is no ordinary depiction of the heavens. While the image portrays the outline of our Galaxy, the Milky Way, and of its neighbouring Magellanic Clouds, it was obtained in a rather unusual way.  
 
As Gaia scans the sky to measure positions and velocities of a billion stars with unprecedented accuracy, for some stars it also determines their speed across the camera's sensor. This information is used in real time by the attitude and orbit control system to ensure the satellite's orientation is maintained with the desired precision.
These speed statistics are routinely sent to Earth, along with the science data, in the form of housekeeping data. They include the total number of stars, used in the attitude-control loop, that is detected every second in each of Gaia's fields of view.
It is the latter – which is basically an indication of the density of stars across the sky – that was used to produce this uncommon visualisation of the celestial sphere. Brighter regions indicate higher concentrations of stars, while darker regions correspond to patches of the sky where fewer stars are observed.
The plane of the Milky Way, where most of the Galaxy's stars reside, is evidently the brightest portion of this image, running horizontally and especially bright at the centre. Darker regions across this broad strip of stars, known as the Galactic Plane, correspond to dense, interstellar clouds of gas and dust that absorb starlight along the line of sight.
The Galactic Plane is the projection on the sky of the Galactic disc, a flattened structure with a diameter of about 100 000 light-years and a vertical height of only 1000 light-years.
Beyond the plane, only a few objects are visible, most notably the Large and Small Magellanic Clouds, two dwarf galaxies orbiting the Milky Way, which stand out in the lower right part of the image.
A few globular clusters – large assemblies up to millions of stars held together by their mutual gravity – are also sprinkled around the Galactic Plane. Globular clusters, the oldest population of stars in the Galaxy, sit mainly in a spherical halo extending up to 100 000 light-years from the centre of the Milky Way.
The globular cluster NGC 104 is easily visible in the image, to the immediate left of the Small Magellanic Cloud. Other globular clusters are highlighted in an annotated version of this image.
Interestingly, the majority of bright stars that are visible to the naked eye and that form the familiar constellations of the sky are not accounted for in this image because they are too bright to be used by Gaia's control system. Similarly, the Andromeda galaxy – the largest galactic neighbour of the Milky Way – also does not stand out here.
Counterintuitively, while Gaia carries a billion-pixel camera, it is not a mission aimed at imaging the sky: it is making the largest, most precise 3D map of our Galaxy, providing a crucial tool for studying the formation and evolution of the Milky Way.
Acknowledgement: this image was prepared by Edmund Serpell, a Gaia Operations Engineer working in the Mission Operations Centre at ESA's European Space Operations Centre in Darmstadt, Germany
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GAIA SATELLITE AND AMATEUR ASTRONOMERS SPOT ONE IN A BILLION STAR
The Gaia satellite has discovered a unique binary system where one star is 'eating' the other, but neither star has any hydrogen, the most common element in the Universe. The system could be an important tool for understanding how binary stars might explode at the end of their lives.  
 
An international team of researchers, with the assistance of amateur astronomers, have discovered a unique binary star system: the first known such system where one star completely eclipses the other. It is a type of two-star system known as a Cataclysmic Variable, where one super dense white dwarf star is stealing gas from its companion star, effectively 'cannibalising' it.
The system could also be an important laboratory for studying ultra-bright supernova explosions, which are a vital tool for measuring the expansion of the Universe. Details of the new research will be published in the journal Monthly Notices of the Royal Astronomical Society.
The system, named Gaia14aae, is located about 730 light years away in the Draco constellation. It was discovered by the European Space Agency's Gaia satellite in August 2014 when it suddenly became five times brighter over the course of a single day.
Astronomers led by the University of Cambridge analysed the information from Gaia and determined that the sudden outburst was due to the fact that the white dwarf – which is so dense that a teaspoonful of material from it would weigh as much as an elephant – is devouring its larger companion.
Additional observations of the system made by the Center for Backyard Astrophysics (CBA), a collaboration of amateur and professional astronomers, found that the system is a rare eclipsing binary, where one star passes directly in front of the other, completely blocking it out when viewed from Earth. The two stars are tightly orbiting each other, so a total eclipse occurs roughly every 50 minutes. The follow-up campaign was  also using many professional telescopes, among others the ones located in the Canary Islands, where observing time was made available through the International Time Program.
"It's rare to see a binary system so well-aligned" said Dr Heather Campbell of Cambridge's Institute of Astronomy, who led the follow-up campaign for Gaia14aae. "Because of this, we can measure the system with great precision in order to figure out what these systems are made of and how they evolved. It's a fascinating system – there's a lot to be learned from it."
Using spectroscopy from the William Herschel Telescope in the Canary Islands, Campbell and her colleagues found that Gaia14aae contains large amounts of helium, but no hydrogen, which is highly unusual as hydrogen is the most common element in the Universe. The lack of hydrogen allowed them to classify Gaia14aae as a very rare type of system known as an AM Canum Venaticorum (AM CVn), a type of Cataclysmic Variable system where both stars have lost all of their hydrogen. This is the first known AM CVn system where one star totally eclipses the other.
"It's really cool that the first time that one of these systems was discovered to have one star completely eclipsing the other, that it was amateur astronomers who made the discovery and alerted us," said Campbell. "This really highlights the vital contribution that amateur astronomers make to cutting edge scientific research."
AM CVn systems consist of a small and hot white dwarf star which is devouring its larger companion. The gravitational effects from the hot and superdense white dwarf are so strong that it has forced the companion star to swell up like a massive balloon and move towards it.
The companion star is about 125 times the volume of our sun, and towers over the tiny white dwarf - which is about the size of the Earth. This is similar to comparing a hot air balloon (companion) and a marble (white dwarf). However, the companion star is lightweight, weighing in at only one percent of the white dwarf's mass.
"This is an exquisite system: a very rare type of binary system in which the component stars complete orbits faster than the minute hand of a clock, oriented so that one eclipses the other." said Prof. Tom Marsh  of the University of Warwick. "We will be able to measure their sizes and masses to a higher accuracy than any similar system; it whets the appetite for the many new discoveries I expect from the Gaia satellite."
AM CVn systems are prized by astronomers, as they could hold the key to one of the greatest mysteries in modern astrophysics: what causes Ia supernova explosions? This type of supernova, which occurs in binary systems, is important in astrophysics as their extreme brightness makes them an important tool to measure the expansion of the Universe.
In the case of Gaia14aae, it's not known whether the two stars will collide and cause a supernova explosion, or whether the white dwarf will completely devour its companion first. "Every now and then, these sorts of binary systems may explode as supernovae, so studying Gaia14aae helps us understand the brightest explosions in the Universe," said Dr Morgan Fraser of the Institute of Astronomy.
"This is an awesome first catch for Gaia, but we want it to be the first of many," said the Institute of Astronomy's Dr Simon Hodgkin, who is leading the search for more transients in Gaia data. "Gaia has already found hundreds of transients in its first few months of operation, and we know there are many more out there for us to find."
The research was supported by ESA Gaia, DPAC, and the DPAC Photometric Science Alerts Team. DPAC is funded by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.
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ASTEROIDS ALL AROUND
Eight months of Gaia data and a sample of 50,000 asteroids were used to test the detection efficiency of software in the Gaia processing pipeline.  
 
Gaia observes more than a billion stars on the whole sky, without knowing in advance where they are. However, as each source is observed multiple times, the Initial Data Processing (IDT, a highly sophisticated piece of software running on the data transmitted by the satellite, developed by the University of Barcelona team) has the task of grouping together multiple observations of the same source.
This task, the so-called "cross-matching", involves comparing the positions recorded by Gaia. If two sources are observed, within the uncertainty, at the same position on the sky they are recognized to be – in fact – the same source.
For asteroids, this cannot work, as they are always moving amongst the stars - slowly (typically, an asteroid in the Main Belt can take a couple of days to move a distance of a Moon diameter) but fast enough for Gaia (several pixels during a single transit on the focal plane)! As a result, Gaia never sees an asteroid at the same place, and the cross-matching described above leaves these detections as "orphans" that do not repeat over time.
Such "un-matched" observations are processed by software running at the CNES data processing center (in Toulouse, France), written by several European astronomers under the coordination of P. Tanga (Observatoire de la Côte d'Azur, France). The first task of this software is the identification of known asteroids that can proceed only by comparing the position of the "orphan" detections to the predictions provided by a specific software module. The reference data, in this case, are the known asteroid orbits (a few 100,000 objects), that are used to generate the position of all of them for any Gaia measurement of a moving source.
Such a procedure has been implemented in the processing pipeline by J. Berthier (IMCCE) and collaborators and has been applied independently (by F. Mignard and L. Galluccio, OCA, France) on eight months of Gaia data and a sample of 50,000 asteroids to test its detection efficiency and to get a flavour of the performance of asteroid identification.
The picture above is one of the results of such a test, showing where Gaia has seen asteroids on the sky. The reference frame for the plot is equatorial, implying that the ecliptic (the orbital plane of the Earth and – also – of most other Solar System objects) appears inclined with respect to the celestial equator, and follows the sinusoidal path on which the asteroids cluster. A total of 418,000 observations by Gaia, over that period, have been successfully associated to one of the asteroids of the sample, a number very close to the expectations.
The colour of the dots is related to the accuracy of the identification, in other words to the distance between the position detected by Gaia and the one predicted by the computation of the ephemerides. For most asteroids, the identification works well (the discrepancies are less than 1 arcsec) but for others – whose orbit is poorly known – identification may become tricky and requires further processing steps.
Interestingly, the plot clearly shows a region of mixed colours, very localised, where large errors seem to be more frequent. In fact, in that region, the ecliptic crosses the Galactic plane, not far from its densest parts. The high stellar density complicates the task of IDT cross-matching, and more stars there, remaining un-matched, are incorrectly considered as asteroids. Their positions correspond to some predicted asteroid positions only by chance, so that they show up with larger discrepancies. This is an expected effect of lower efficiency in extremely crowded areas of the sky, which are very limited in size.
In fact, both statistics and analysis of samples of individual objects show that Gaia is very efficient in detecting asteroids, and the whole expected population is being observed, within a few percent of the completeness at the magnitude limit of the mission.  
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DEMONSTRATING GAIA'S ASTROMETRIC POTENTIAL
Hertzsprung-Russell diagrams based on provisional absolute parallaxes determined by the first Tycho-Gaia Astrometric Solution. Distances for stars with less than 20% (figure above) and 10% (figure below) relative parallax uncertainty (formal standard errors) were used to convert the apparent Tycho-2 magnitudes into the absolute magnitudes on the y-axis. Stars in the Hipparcos catalogue and stars with formal parallax uncertainties larger than 1 milliarcsec were omitted. Awaiting Gaia's own extensive photometric survey, the colour indices J-K on the x-axis were taken from the ground-based 2MASS catalogue. The absolute magnitudes and colour indices have not been corrected for interstellar extinction.
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The Hertzsprung-Russell (HR) diagrams presented here were produced as part of a first validation of the astrometric capabilities of the instrument and of the Basic Angle variation measured by the on-board interferometer (Basic Angle Monitor; BAM). Based on less than one year of data from the routine observation phase of Gaia, they give an exciting hint of what the mission will deliver.
In principle the Gaia data collected until now are not yet sufficient for disentangling the parallax and proper motion of a star. However, by using an earlier-epoch position, the degeneracy can be lifted already now. For this study we used a Tycho-Gaia Astrometric Solution (TGAS; see article "The Tycho-Gaia Astrometric Solution" and A&A paper) to calculate provisional Gaia parallaxes for more than a million Tycho-2 stars. The astrometric observations were corrected for variations of the Basic Angle, as determined by the BAM. Without such a correction, the parallaxes would have been strongly biased due to the 1 mas amplitude Basic Angle variation.
Much further work is needed to prepare the data releases and to gain full confidence in the resulting astrometric parameters. Nevertheless, the above diagrams demonstrate the overall correctness and readiness of the data processing chain, the quality of the Gaia instrument, and strengthen the confidence that the impact of the Basic Angle variations can be eliminated from the final astrometric results
Quelle: ESA/Gaia/DPAC/IDT/FL/DPCE/AGIS

Tags: Astronomie 

1612 Views

Samstag, 15. August 2015 - 15:25 Uhr

Mars-Chroniken - Indiens Mars Orbiter Erfasst eindrucksvollen Blick auf Mars Canyons

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India's Mars Orbiter, which arrived at the Red Planet late last year, has just sent back a beautiful shot of the Ophir Chasma, a system of deep valleys and scalloped terrain in the Valles Marineris region. Areas with major geological features like this tend to show off the various layers of materials making up the surface. The picture above was taken July 19 from 1,857 kilometers (1,154 miles), but the scientists at the Indian Space Research Organisation also reconstructed what it might look like from nearby.

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Reconstructed 3-D view of the Ophir Chasma on Mars. ISRO
The "Mangalyaan" orbiter has been a major success story. It was constructed on a budget a fraction the size of most space missions — in fact, it cost less than the blockbuster space film "Gravity." It's not carrying state-of-the-art equipment like NASA's Maven orbiter, which entered orbit at nearly the same time. India's mission is more of a proof of concept, showing that the country is more than capable of undertaking serious space exploration.
This success not only means great views like this one, but validation of ISRO's technology and methods. Mangalyaan's original six-month mission is long over, but the orbiter will continue sending data as long as it remains functional.
Quelle: NBC News

Tags: Mars-Chroniken 

1621 Views

Samstag, 15. August 2015 - 12:00 Uhr

UFO-Forschung - Außerirdische Flugobjekte bei der UFO-Meldestelle von CENAP

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Weiterer UFO-Meldeeingang bei UFO-Meldestelle von CENAP, darunter "wirklich außerirdische Flugobjekte" welche wissbegierige Zeugen meldeten und wir ihnen helfen konnten mit Antworten auf die Frage WAS sie gesehen haben, manchmal auch direkt LIVE!

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9.08.2015 - Köln-Bickendorf

Diese Email erreichte uns:

Guten Abend Herr Köhler,
ich hatte gestern Abend (09.08.2015) eine UFO-Sichtung, es wäre schön wenn Sie mir helfen könnten, dieses zu identifizieren.
Zu den Fakten:
1. Ort der Beobachtung: Bei mir zu Hause (Köln-Bickendorf, 50827). Ich schaute aus dem Fenster und sah „es“ am Himmel
2. Uhrzeit/Dauer: Ich habe direkt auf die Uhr geschaut und es war 23:01 Uhr MESZ. Das Phänomen war knapp eine halbe Minute zu beobachten
3. Was ist passiert:
Ich sah aus dem Augenwinkel einen hellen Punkt im Himmel, etwas größer noch als der hellste Stern am Himmel. Er bewegte sich relativ gleichmäßig in einer Geschwindigkeit, wie die eines Flugzeugs in Richtung Osten. Zuerst habe ich gedacht/(gehofft) es wäre die ISS gewesen (hab ich auch schon mal bewusst gesehen), aber dafür war es zu hell.
Dann dachte ich natürlich an ein Flugzeug, aber da es nur ein gleichmäßig heller Punkt im Himmel war, ohne Positionslichter oder Strobe lights kam auch dies nicht in Frage (ich arbeite am Flughafen und studiere Luftverkehrsmanagement, sodass ich ziemlich gut beurteilen kann, wie ein Flugzeug aussieht und sich bewegt).
Für einen Hubschrauber war dieses Gebilde zu hoch, zu hell und zudem völlig geräuschlos, was zusätzlich ein Argument gegen ein Luftfahrzeug darstellt.
Auch eine Himmelslaterne war es nicht. Die habe ich auch schon gesehen und dafür flog sie zu schnell.
Das mysteriöseste ist jedoch, dass nach knapp 30 Sekunden der sehr helle Punkt langsam anfing konstant an Leuchtkraft zu verlieren, bis er irgendwann verschwunden war, nachdem es vorher konstant hell schien.
Das einzige was ich nicht komplett ausschließen kann, wäre ein Meteor, aber dafür war es doch ziemlich lange, sehr konstant und hatte auch keinen Schweif oder ähnliches. Außerdem verglühte es nicht einfach, sondern der große helle Punkt wurde von außen weg immer kleiner und verschwand.
Leider hat es sonst bei mir im Haus keiner gesehen, da ich alleine war zu dem Zeitpunkt.

Ich hoffe meine Erklärungen waren einigermaßen verständlich und ich bedanke mich schon einmal für Ihre Mühen.
Über eine Antwort würde ich mich sehr freuen!
Mit freundlichen Grüßen M.E.
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Unsere Überprüfung der üblich Verdächtigen erfolgte ebenso wie der Check von ISS-Überflug trotz der Aussage des Zeugen (er meinte: ISS nicht so hell wäre). Wir wurden dann doch bei dem "außerirdischen Flugkörper" fündig. Genau zu der angegebenen Zeit war ISS im Begriff über Europa zu ziehen und auch von Köln-Bickendorf aus zu sehen wie die Standort-Abfrage der ISS-Sichtbarkeit für Köln-Bickendorf ergab:
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Identifizierung: ISS Internationale Raumstation
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9.08.2015 - Leipzig
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Am 10.August erreichte uns über die UFO-Meldestelle Frau H. aus Leipzig, nach dem ihr Ehemann unsere UFO-Meldestelle über das Internet gefunden hatte. Frau H. hatte am 9.August gegen 23.10 MESZ ihren HUnd ausgeführt und dabei die klare Sommernachtfür das "Sternengucken" genutzt, hierbei file ihr plötzlich bei Sternbild Cassiopeia ein helles Licht aufblitzen auf welche sich insgesamt 3 mal in einer gedachten Flugbahn ereignete und sie mit großem Fragezeichen stehen lies. 
Blick auf aktuelle Astro-Karte zu gegebenen Beobachtungszeitpunkt:
Unsere Recherchen ergaben dann einen Satelliten-Überflug von COS-B welcher zur angegebener Zeit  in der Nähe von Cassiopeia aufleuchtete und durch seine Rotation dieses Aufleuchten verursachte.
Nachfolgend die Überflugskizze von COS-B:
COS-B-Satellit wurde 1975 gestartet und stellte 1982 seinen Betrieb ein und umkreist rotierend die Erde :
Identifizierung: ESA COS-B-Satellit
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11.08.2015 - Gaggenau
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Diese Mails bekamen wir von zwei Zeugen aus Gaggenau bei Karlsruhe:
Hallo Leute,
habe vor ca einer 3/4 Stunde evt auch Stunde ein Dreiecks/Kegelförmiges helles Licht am Himmel über Gaggenau (76571) wahrgenommen, welches sich recht schnell bewegte.
Es war heller als jeder heute zu sehende Stern (deshalb schließe ich Satelit mal aus...aber bin da kein Fachmann).
Es bewegte sich räumlich nach vorne und hinten, nachdem es sich linear fortbewegt hatte. Wie gesagt ziemlich schnell. Das Licht wurde mit zunehmender Entfernung wärmer. Ging bis ins orangene.
In der näöchsten nichteinmal halben Stunde nahm ich weitere 8 Flugobjekte (Flugzeuge, die jedoch erstaunlich laut wahren, dafür das sie so seltsam Tief geflogen sind) wahr.
Ich meine es tatsächölich ernst und bin etwas verwirrt...hab sowas noch nie gesehen. Gab es zufällig ähnliche Meldungen in der Sichtweite?
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In der zweiten Rückantwort-Mail kamen zusätzliche Infos zur Beobachtung:
Hallo Herr Köhler,
dies waren laut Google Maps die Koordinaten unseres gestrigen Aufenthaltsortes: 48°47'54.8"N 8°19'19.8"E
Direkt gegenüber von der Avia Tankstelle (Hauptstraße 40).
Es flog richtung Osten.
Ich persönlich muss zugeben, dass der Flugkörper für mich wie ein sich bewegender Stern ausgesehen hat. Er war einfach nur sauschnell!
Mein Kumpel meinte jedoch es hätte eine Dreieckige Grundfläche. Also einfach ein Dreieck. Es kann durchaus sein, dass sich das Licht durch
meine Brille anders gebrochen hat und ich es deshalb nicht so gesehen habe.
Was ich evt auch nochmal erwähne, weil ich es gestern iwie schlecht formuliert habe ist die Route. Ich habe gesagt es hat sich erst linear
und dann nach vorne hinten bewegt. Dies war evt etwas missverständlich. Es hatte den anschein das es (nachdem es sich linear bewegt hatte) von der erde wegfliegt, aber schräg nach vorne (siehe Skizze).
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Uhrzeit wird schlecht, da wir beide keine Uhr hatten und uns in dem moment auch echt egal war wie viel Uhr es war....es muss ca 23 Uhr gewesen sein...könnte aber auch 10 vor 23 uhr gewesen sein...
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Auch in diesem Fall spricht sehr viel für den ISS-Überflug auch wenn die Zeitangabe zu wünschen übrig lässt. Da die Standortfrage für den Überflug der ISS positiv (flög 22.50 MESZ über Gaggenau) ausfiel und auch die Uhrzeit-Schätzung des Zeugen streift, gehen wir von dem auffälligen ISS-Überflug aus. Nachfolgende Skizze und Angaben zum ISS-Überflug-Standort Gaggenau:
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Identifizierung: ISS Internationale Raumstation
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12.08.2015 - Suttgart-Neugereut

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Gegen 1.10 MESZ vom 12.August meldete sich Ehepaar G. aus Neugereut bei Stuttgart über das UFO-Meldestelle Telefon und beobachtete seit geraumer Zeit "ein tanzendes Licht am Himmel" zusammen mit ihrer Mutter. Zusammen nutzten sie die angenehmen Nachttemperaturen um im Garten den Sternenhimmel nach Perseiden zu beobachten. Hierbei fiel ihnen ein helles weiß,blau,rot blinkendes Licht auf, das sich scheinbar bei genauen Anpeilen über einen Holzstock "zwischen 5-8 mm hin und her bewegte"! Alle drei Personen wollten nun wissen was sie hier beobachteten und so mit begann eine Astronomie-Stunde LIVE. Der Ehemann hatte eine Astro-App und konnte so angeben, das es sich rechts bei Sternbild Schwan befände. Da ich auch das Astro-Programm auf meinem PC hochgefahren hatte, begann "die Ortung des hellen Lichts". Blick auf gegebene Astro-Karte während des Telefon-Gesprächs:

Hierbei wurde es immer klarer, hier Wega die Beobachter mit ihrem Schein faszinierte, nach dem auch Lyra erkannt wurde welche bei "dem hellen Licht stand". Inzwischen waren es die Begleitumstände von Wega welche dann durch die Erd-Atmosphäre sowie der Überkopfbeobachtung zu dem "Farbenblinken und scheinbaren 5-8 mm Bewegungen" führte:

Identifizierung: Stern Wega

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13.08.2015 - Ludwigshafen

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Bei meiner Perseiden-Beobachtungs-Nacht im Odenwald, erreichte mich Herr G. um 0.49 MESZ aus Ludwigshafen, welcher zusammen mit seiner Freundin "ein helles Licht wie ein Flugzeugscheinwerfer" sahen und er noch sehen würde, nach dem er seine Freundin nach Hause gebracht hatte. Da ich mich auf einer Anhöhe im Odenwald zur Perseiden-Beobachtung befand und eine 360° Grad-Umsicht hatte, suchten wir gemeinsam LIVE am Telefon erst einmal die Himmelsrichtung. Hierbei lief der junge Mann erst einmal ein paar Schritte um von einer hellen Straßenlaterne weg zu kommen und so erkannte er das Sternbild des großen Wagens, und das helle Licht befand sich Links davon. Auch wenn ich dann Arcturus als Kandidat am Westhimmel ausmachte, wurde ein Screenshot von Astro-Karte auf Laptop  angefertigt und konnte die Identifizierung erfolgen.                                   Blick auf Astr-Karte:

Identifizierung: Stern Arcturus

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CENAP-Mannheim, hjkc


Tags: UFO-Forschung 

2169 Views

Freitag, 14. August 2015 - 22:45 Uhr

Raumfahrt - ESA-Sonde Rosetta/Philae auf Komet 67P/Churyumov-Gerasimenko - Update-36

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14.08.2015 / 9.34 MESZ

Rosetta captures images of jet-blasting comet
Cameras of European Space Agency craft get within 330km of comet 67P as it hurtles past sun, rattles its ‘guest’, Philae, and spews out gas and boulders
Cameras on the Rosetta spacecraft captured powerful jets of steam and dust erupting from comet 67P as it tore past the sun on Thursday morning. Images beamed back from the probe showed the comet spewing material as it warmed up on its closest pass of the sun and began its journey back out into the frigid far reaches of the solar system.
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Pictures taken a few hours before the comet’s close encounter with the sun recorded one powerful outburst that flung a visible, bright, stream of dust and vapour several kilometres into space.
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Holger Sierks, the lead scientist on Rosetta’s Osiris camera, compared the jet blasting from the spinning comet to a garden water sprinkler. “It’s the first time this has been seen in space,” he said.
When Rosetta, which was built and launched by the European Space Agency, arrived at the comet in August last year its surface temperature was a chilly -70C (-94F). But as the comet swung closer to the sun, its surface warmed. In May, the comet was a few degrees below 0C (32F). Over the next month, it could reach 30C.
The rise in temperature has transformed the comet from a dull and frozen lump into a body billowing furiously as it tumbles through space. The amount of water being shed from the comet has risen 1,000-fold in the past year. The comet now sheds 300kg of water every second, enough to fill an Olympic swimming pool every two-and-a-half hours. The vapour leaving the comet dislodges a tonne of dust every second.
Other images released by the Rosetta team on Thursday showed a boulder being blasted off the surface of the comet and out into space. Sierks said the boulder was spinning at five revolutions a second and going fast enough to leave the comet, which has a length of about 4km (2.4 miles) for good rather than go into orbit around it. Mission scientists are still calculating the size of the boulder, but said it was between four metres and 40 metres wide. 
Much of the gas and debris dislodged from the surface forms the comet’s atmosphere or coma, or helps to build up its spectacular tail. Rosetta is too close to image the comet’s tail directly, but groundbased telescopes have measured it stretching out across 120,000km (74,564 miles).
Rosetta orients itself by the stars and has had to back away from the comet to prevent its star trackers from being blinded by dust. The latest images were taken at about 330km away from the comet. At such a distance Rosetta’s cameras cannot see whether a 500-metre crack in the neck of the comet has widened. At some point the comet could break in two, but the chances of that happening while Rosetta is orbiting the comet were minuscule, said Sierks.
Down on the surface the conditions are becoming ever more violent for the little Philae lander, which, in November last year, became the first to touch down on a comet. The ESA lander has not been heard from in the past month, but scientists hope it may still make contact now that it is receiving more sunlight to charge its batteries and Rosetta has flown back up to the comet’s north where communcation links are easier.
Barbara Cozzoni, Philae operations engineer, said the powerful vapour jets were unlikely to knock Philae off the comet but might push it into a bad position where it could not call home. “There’s a danger that it might change the attitude of Philae,” she said. The team is now working on a way to send commands to Philae in the hope of getting fresh data back from the battered lander.
Rosetta will escort the comet out towards Jupiter until September 2016 when flight controllers will fly lower and lower around the comet until the spacecraft crash lands. 
“I’d bet on a hardish landing,” said Armelle Hubault, spacecraft operations engineer. “There are boulders and mountain-sized rocks everywhere. It’s very likely the spacecraft will hit one of those and stumble at the end. So it will not be very graceful.”
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Quelle: theguardian
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Update: 22.45 MESZ
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A SHAPE MODEL – WHAT’S THAT?
Today, a new shape model of Rosetta’s comet is released by ESA. Some of you might immediately know what this is and how you might use it, and others will wonder ‘what’s that?’  This blog post, which has been prepared with the help of experts from the Rosetta Flight Dynamics team, explains what a shape model is, how it is created, and what you could use it for.
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The ESA NavCam shape model that is released today. Credit: ESA/Rosetta/NAVCAM, CC BY-SA IGO 3.0
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At the most basic level, a shape model is a geometrical representation of an object. Shape models are commonly used in computer programmes where the motion or change of shape of a complex object needs to be represented. Applications can vary from medical imaging of organs, creating characters in cartoons and computer games, or — closer to home (at least for the Rosetta team) — modelling how the surface of a comet changes as it rotates.
Back in the summer of 2014, the Rosetta mission operations and flight dynamics teams were faced with the mammoth task of figuring out how to approach and navigate around Comet 67P/Churyumov-Gerasimenko. After a year of marvellous close-up views of this comet it’s easy to forget that early models of the comet bore very little resemblance to the reality.
The first hints that the comet might not have a simple shape came in July 2014, when images taken by the scientific camera, OSIRIS, revealed a double-lobed object. It was soon clear that navigation would be a challenge, and an important factor in successful navigation would be a robust shape model.
The first, crude shape models were constructed by the flight dynamics team, using a method called silhouette carving. For this, software is used to map the silhouette of the comet, as seen in NavCam images, onto a large ‘virtual’ body and the parts of the body that extend beyond the silhouette are removed. As more and more images of different regions, taken from different perspectives, are added, the shape of the comet starts to emerge.
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This image shows an example of a crude shape model generated using the silhouette carving method. The colours are the default settings used in the software tool mathematica. This silhouette carving approach was the first step in creating a shape model that could eventually be used for navigating around 67P/C-G. Credit: ESA
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The next step was to identify landmarks on the surface of the comet that could be used to create a framework of reference positions. For the first shape models, the team identified, by hand, 30 landmarks — easily recognisable features such as pits, valleys, or bumps — to make ‘maplets’. These maplets are small, 3D high-resolution maps. The first maplets covered 500 m x 500 m with 10 m resolution, while during closest approach to the comet the maplets covered 100 m x 100 m with 1 m resolution.
The maplets are generated by stereophotoclinometry, a technique that uses stereo images of regions of the surface and finds slopes by examining the way the surface looks under different illumination conditions. Once the slopes are known then the surface height can be inferred.
These maplets were then projected onto the crude shape model to provide a more detailed shape model. For recent shape models the team now use about 1000 landmarks, which are automatically identified from NAVCAM images.
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This fine-detail shape model is an example of one generated using the stereophotoclinometry method. This method was also used to generate the ESA shape model that was released today. Credit: ESA
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The ESA NAVCAM shape model is a core tool used by the team to precisely navigate around 67P/C-G. Each day, the positions of landmarks are identified in the most recent NAVCAM images and are provided to the orbit determination team who use this information to establish the position of the spacecraft with respect to the comet, and to plot the new trajectory. The orbit details are updated twice a week and are used by mission planners to devise the future orbits, and by the instrument scientists to plan their observations.
In addition to these operational aspects, a shape model is also an important tool for scientists analysing images and data from Rosetta. Such models can be used for calibrating data, studying changes on the surface, and for investigating the geology and morphology of the comet. The OSIRIS team have produced a number of shape models in the course of the past year which have been used by Rosetta scientists to select the landing site for Philae, and to determine physical properties of the comet, such as size, volume, and density, as well as measuring the rotation of the comet, its gravitational potential, and tracking changes on the surface.
And it’s not just people working directly on the mission who produce shape models. Mattias Malmer, an image processing expert and a space enthusiast, has developed a shape model based on publicly released NAVCAM images. This is accompanied by a ‘texture’ file that indicates the boundaries between the different geomorphological regions that scientists have identified on the comet.
Apart from the very specific operational or scientific applications that the Rosetta teams have for shape models, there are plenty of other uses for these models, such as printing your own 3D model of the comet or creating visualisation tools, such as the View Rosetta’s comet tool that is released today.
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NEW: INTERACTIVE VIEWER FOR COMET 67P/C-G
In the week that we celebrate a year that Rosetta has been at Comet 67P/Churyumov-Gerasimenko and mark their passage through perihelion, we are delighted to present a new interactive tool that allows you to explore the shape and surface of this intriguing comet.
View Rosetta’s comet is based on images taken with Rosetta’s navigation camera, NAVCAM. Since November 2014, these images have been released under a Creative Commons license, which allows you to share them with whomever you like, to publish them on your blog or elsewhere, as well as to adapt, process, and modify them.
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Screen shot from the View Rosetta's comet interactive tool.
As of 30 July this year, more than 6800 NAVCAM images are available to download from ESA’s Archive Image Browser, and that number will increase with the regular addition of many more as Rosetta's mission continues.
From reactions that we’ve had on this blog, via social media, and meeting people at events we know that many of you are intrigued and fascinated by Comet 67P/C-G — as we are.
As far back as August last year, when the unusual shape of this comet became clear, we saw the need for an interactive way of exploring the surface of the comet. More recently, we started to wonder about what could be done with the Rosetta images and 3D computer models of the shape of the comet.
A conversation that started on a Friday evening as a "Wouldn’t it be great if we had an interactive way to view the comet?" set our colleague Oliver Jennrich thinking, and by the following Monday morning he had come up with a simple prototype tool using a shape model that had been developed by Mattias Malmer an image processing expert and space enthusiast living in Sweden. Mattias used publicly available NAVCAM images to generate his model and then made it available via his own website.
With this basic tool, it was possible to zoom in and out, and rotate and pan across the comet. This was already better than anything we had in the Rosetta communications team, but as soon as we starting playing with it more ideas started to flow.
Could we add the geological regions that have been identified on the comet's surface? Could we tie this tool in with the huge repository of NAVCAM images in the Archive Image Browser? Could we include other shape models?
Over the next few weeks, Oliver implemented a number of new features, including a texture map made by Mattias to add the regions identified by Nicolas Thomas and colleagues in their scientific analysis of 67P/C-G.
Then Oliver added a trail of points along Rosetta’s trajectory to show where images of the comet have been taken by NAVCAM. That made it possible to link the tool to the NAVCAM database, to view and allow downloads of the corresponding images.
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View Rosetta's comet interactive tool provides access to some of the best NAVCAM images in the ESA Archive Image Browser.
With subsequent support from João Martinho Moura and colleagues at Science Office, who also worked on our Where is Rosetta? tool, the code was optimised and the interface fine-tuned. Most recently, a separate ESA NAVCAM shape model, developed by the ESA Flight Dynamics team, was made available for release and has been added to the tool as an option.
You can find more detailed information about the tool here. (Note that the viewer does require a WebGL-enabled browser and graphics card.)
But this is just the beginning! It’s clear to us that there is a lot of scope to develop the tool further, but we want to make this ‘beta’ version available to you now, at the time of perihelion, to enjoy and try out.
We aim to make further releases ourselves, but the code is available as open source, so feel free to take it and develop it further — we hope you do!
Share with us your comments about your experience, including your possible enhancements of the viewer, or new ways that you have found to use the images and shape models, via the comments block below.
Stay tuned for more NAVCAM images and updates to this tool.
And don’t forget to join us later today, at 15:00 CEST, for a Google Hangout with Rosetta mission experts as we celebrate perihelion.
Quelle: ESA

Tags: Raumfahrt 

1545 Views

Freitag, 14. August 2015 - 17:25 Uhr

UFO-Forschung - Annabergfest-Ufo war nur Zieldarsteller, keine Drohne

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Nur Zieldarsteller, keine Drohne
Das Rätsel ist gelöst: Das Annabergfest-Ufo war ein kleiner Jet, der im Auftrag der Bundeswehr ein Luftziel darstellen sollte - also doch keine US-Späh-Drohne, wie viele der Bergfestbesucher mutmaßten. Gestern hatten die SRZ-Recherchen Erfolg.
Die Abteilung Flugbetrieb der Bundeswehr hatte nach unserer detaillierter Anfrage die richtige Auskunft parat: "Die Überprüfung ergab für den von Ihnen angegebenen Zeitraum keinen Anhaltspunkt für einen Übungsflugbetrieb mit unbemannten Luftfahrzeugen. Jedoch können die angegebenen Flugbewegungen dem angemeldeten Flug eines zivilen Luftfahrzeugs, welches im Auftrag der Bundeswehr als Zieldarsteller fungierte und im Bereich des Truppenübungsplatz Grafenwöhr flog, zugeordnet werden." 
Dieses Luftfahrzeug sei auch mehrmals genau zu den angegebenen Zeiten in den Abendstunden im Luftraum über den beschriebenen Gebieten zwischen Edelsfeld und Sulzbach gekreist. Der kleine Jet mit seinem Piloten habe sich in einer Höhe von circa 1300 Meter über Grund im Landkreis Amberg-Sulzbach befunden - das entsprach laut Bundeswehr den flugbetrieblichen Vorschriften. "In diesen Höhen werden üblicherweise zu diesen Tageszeiten zur Verhütung von Zusammenstößen mit anderer Luftverkehrsteilnehmer, die Landescheinwerfer eingeschaltet. 
Im Dschungel der Auskünfte - Angemerkt von Joachim Gebhardt
"Was fliegt denn da?", heißt ein bekanntes Vogel-Buch. Am Annabergfest stellten sich viele Besucher heuer auch diese Frage, als sie am Nachthimmel mehrfach ein Flugobjekt mit Scheinwerfer wahrnahmen. Das gute einheimische Festbier, sonst gern Ursache für allerlei paranormale Phänomene wie lokale Erdschwankungen, war diesmal unschuldig. 
Logisch, dass die Zeitung da nachforscht. Zunächst über das Landratsamt, dann über die US Army. Keiner weiß von nichts, möchte man fast sagen. Beim Luftfahrt-Bundesamt hat man Urlaub. "Schicken Sie halt eine E-Mail!" Wann liest die Referentin das denn? "Keine Ahnung!" Neue Vermittlung. Plötzlich der Anrufbeantworter der Ufo-Forschungsgesellschaft. "Melden Sie uns Ihre Beobachtungen!" Nie mehr Festbier... 
Endlich eine Spur: Flugbetrieb der Bundeswehr in Köln. E-Mail, Anruf, sofortige Antwort und erwünschte Auskunft. Respekt. Auch die Gesellschaft zur Flugzieldarstellung ist kooperativ: "Das war unser Jet!" 
Fall geklärt, keine US-Drohne, kein Ufo, nur Bundeswehr-Übungsbetrieb in Grafenwöhr mit Außenwirkung. Die NSA weiß also immer noch nicht, wie viele Maßen wir am Berg getrunken haben. Wir könnten ihr da aber auch nicht wirklich helfen. Und außerirdisch (gut) waren dort nur zwei Sachen: das Bier und die Stimmung. Was stört uns da schon so ein Düsenfliegerl...
Quelle: SULZBACHH-ROSENBERGER ZEITUNG

Tags: UFO-Forschung keine Drohne 

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