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Sonntag, 15. Dezember 2013 - 22:33 Uhr

Astronomie - NOAO / SOAR: Wo Sterne und Braune Zwerge am Ende anfangen?

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The relation between size and temperature at the point where stars end and brown dwarfs begin (based on a figure from the publication) Image credit: P. Marenfeld & NOAO/AURA/NSF.

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Stars come in a tremendous size range, from many tens of times bigger than the Sun to a tiny fraction of its size. But the answer to just how small an astronomical body can be, and still be a star, has never been known. What is known is that objects below this limit are unable to ignite and sustain hydrogen fusion in their cores: these objects are referred to as brown dwarfs.
In research accepted for publication in the Astronomical Journal, the RECONS (Research Consortium On Nearby Stars) group from Georgia State University has found clear observational evidence for the theoretically predicted break between very low mass stars and brown dwarfs. The data came from the SOAR (SOuthern Astrophysical Research) 4.1-m telescope and the SMARTS (Small and Moderate Aperture Research Telescope System) 0.9-m telescope at the Cerro Tololo Inter-American Observatory (CTIO) in Chile.
For most of their lives, stars obey a relationship referred to as the main sequence, a relation between luminosity and temperature – which is also a relationship between luminosity and radius. Stars behave like balloons in the sense that adding material to the star causes its radius to increase: in a star the material is the element hydrogen, rather than air which is added to a balloon. Brown dwarfs, on the other hand, are described by different physical laws (referred to as electron degeneracy pressure) than stars and have the opposite behavior. The inner layers of a brown dwarf work much like a spring mattress: adding additional weight on them causes them to shrink. Therefore brown dwarfs actually decrease in size with increasing mass.
As Dr. Sergio Dieterich, the lead author, explained, “In order to distinguish stars from brown dwarfs we measured the light from each object thought to lie close to the stellar/brown dwarf boundary. We also carefully measured the distances to each object. We could then calculate their temperatures and radii using basic physical laws, and found the location of the smallest objects we observed (see the attached illustration, based on a figure in the publication). We see that radius decreases with decreasing temperature, as expected for stars, until we reach a temperature of about 2100K. There we see a gap with no objects, and then the radius starts to increase with decreasing temperature, as we expect for brown dwarfs. “
Dr. Todd Henry, another author, said: “We can now point to a temperature (2100K), radius (8.7% that of our Sun), and luminosity (1/8000 of the Sun) and say ‘the main sequence ends there’ and we can identify a particular star (with the designation 2MASS J0513-1403) as a representative of the smallest stars.”
Aside from answering a fundamental question in stellar astrophysics about the cool end of the main sequence, the discovery has significant implications in the search for life in the universe. Because brown dwarfs cool on a time scale of only millions of years, planets around brown dwarfs are poor candidates for habitability, whereas very low mass stars provide constant warmth and a low ultraviolet radiation environment for billions of years. Knowing the temperature where the stars end and the brown dwarfs begin should help astronomers decide which objects are candidates for hosting habitable planets.
Also, because brown dwarfs cool forever, they eventually become a type of macroscopic dark matter, so it is important to know how much dark matter is trapped in the form of extremely old and cold brown dwarfs.
The research highlights the capabilities of the National Optical Astronomy Observatory system in a single project. The SOAR observations provided the missing link to a wealth of data that had previously been obtained using telescopes under the auspices of NOAO. As Dieterich explains: “We used the SOAR 4.1-m telescope to measure the visible light of faint stars and brown dwarfs, and the CTIO 0.9-m telescope to obtain precise measurements of their distances. We then combined these measurements with infrared data taken at the CTIO 1.3-m telescope and the WISE space telescope. Three out of four of these telescopes are public telescopes located at CTIO, and the fourth explores wavelengths that are only accessible from space.”
CTIO is a division of the National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy Inc. (AURA) under a cooperative agreement with the National Science Foundation.
Quelle: NOAO

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Samstag, 14. Dezember 2013 - 17:30 Uhr

UFO-Forschung - Ufo-Alarm über Mannheim durch Quadrocopter

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Ein Zeuge meldete am Freitag, 13.12. gg. 21.15 Uhr ein unbekanntes Flugobjekt über den Dächern der Nachbarschaft. Vor Ort konnte ermittelt werden, dass es sich bei dem UFO vermutlich um einen ferngesteuerten Quadrocopter handelte. Nicht nur durch das laute Motorengeräusch sondern auch durch die Tatsache, dass diese Fluggeräte regelmäßig mit Kameras ausgestattet sind, führte bei dem Zeugen zu Unbehagen. Das Polizeirevier Käfertal hat die Ermittlungen aufgenommen.

Quelle: MRN-News

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UFO-Stimuli Quadrocopter im Schwarmflug

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49 Quadrocopter bei der Ars Electronica 2012 im Schwarm

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Quadrocopter zeichnen Star Trek Logo über London, Promotion für “Star Trek Into Darkness” Kinostart 17.Mai 2013


4132 Views

Freitag, 13. Dezember 2013 - 21:22 Uhr

Astronomie - Seltener Meteorit blieb seit 140 Jahren unbemerkt

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A rare meteorite that formed soon after the origin of the solar system has been discovered in a private geological collection – 140 years after it fell to Earth. The stone, which is around 4.6 billion years old, was officially handed over to Naturalis Biodiversity Center in Leiden, the Netherlands, earlier this week.

Bright lights and sizzling sounds accompanied the fall of the meteorite on 27 October 1873 in the village of Diepenveen in the Netherlands, according to a contemporary handwritten note. Two witnesses to the fall dug up the small, warm stone and gave it to the local schoolmaster. It remained a school specimen until 2009, when it was given to a collector. Dutch amateur astronomer Henk Nieuwenhuis then "rediscovered" the 5-centimetre-wide space rock when he examined the collection last year.

"It is very unusual for a space rock to remain unnoticed by astronomers and geologists for such a long time," says Leo Kriegsman, a geologist at the Naturalis Biodiversity Center.

The Diepenveen, as the meteorite is now officially called, is only the fifth to have fallen in the Netherlands as far as we know. The find is all the more remarkable because the meteorite turns out to be of a very rare, carbon-rich type known as a CM carbonaceous chondrite – the same type as the one that triggered a meteorite hunt when it fell to Earth in California last year.

"CMs comprise less than 1 per cent of all known meteorites," says geologist Marco Langbroek of the Free University in Amsterdam, where the Diepenveen underwent its first analysis.

CM carbonaceous chondrites contain up to 2 per cent carbon, often in the form of microscopic diamonds. They also contain organic matter like amino acids, which some researchers believe brought the building blocks of life to Earth.

"It is very interesting news," says meteorite researcher Peter Brown of the University of Western Ontario in London, Canada. "CM meteorite falls are indeed rare. If the meteorite has been stored well and not subjected to too much terrestrial contamination it could be quite interesting."

However, fellow meteorite researcher Michael Zolensky of NASA's Johnson Space Center in Houston, Texas, is more cautious. "It will be thoroughly contaminated in any case, so only results for non-terrestrially occurring amino acids may be believable," he says.

Tiny samples of the brittle and porous meteorite are now being studied at laboratories in California, New Mexico and Switzerland. "We hope to publish our analysis results sometime next year," says Langbroek.

Quelle: NewScientist

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New Dutch meteorite fell in 1873

 

The stone has a rare composition of scientific importance.

140 years after its fall to earth, there is official recognition at last: the rock that landed near the Dutch village of Diepenveen back in 1873 is the fifth Dutch meteorite. The “Diepenveen”, as it’s called, has an unusual composition and may contain complex molecules that could perhaps have played a role in the origin of life on earth.

"A blinding light"

Around 3 o’clock in the afternoon of the 27th October 1873, a piece of rock plummeted to earth narrowly missing people working in the fields of Diepenveen, a village lying to the east of the Netherlands near the town of Deventer. “There was a blinding light and much hissing as this rock fell down”, according to the writing on the little wooden box, made to house the meteorite at a later stage.

Then, on the 11th August 2012, nearly 140 years later, amateur astronomer and former Director of the Eise Eisinga Planetarium in Franeker, Henk Nieuwenhuis, came across the rock as part of a collection belonging to a Mrs L. Kiers. “I really couldn’t believe my eyes,” remembers Mr Nieuwenhuis who straightaway recognised the rock as a carbonaceous meteorite. Mr Nieuwenhuis’ identification of this rock as a meteorite was later confirmed through research carried out by astronomer Niek de Kort of the Royal Netherlands Association for Meteorology and Astronomy (KNVWS) and geoscientists Marco Langbroek and Wim van Westrenen of the Vrije Universiteit (VU) of Amsterdam. Initially sceptical, the scientists became very excited as they realised that the rock was indeed an unrecognised Dutch meteorite.

Origin of life on earth

The Diepenveen discovery turns out to be very important internationally because of its unusual composition. It belongs to the relatively large class of so-called ‘stony meteorites’ but within this class, there is a rare sub-class known as ‘carbonaceous chondrites’, to which only about 1% of all meteorites belong, and the Diepenveen meteorite is one of these. Carbonaceous chondrites can contain complex molecules which may have played a role in the origin of life on earth. Analysis of a small piece of the Diepenveen has shown that it does indeed contain organic molecules but what those are exactly is now the subject of further research. Scientists at the Faculty of GeoSciences at the VU University of Amsterdam and Naturalis Biodiversity Center are writing various scientific publications about the Diepenveen meteorite, together with various international organisations.

The Diepenveen meteorite is extremely old, as old as the solar system which formed roughly 4.6 billion years ago. It weighs 68 grams.

History of the find

The researchers are also interested to know whether other bits of rock from around that time in 1873 are hidden away somewhere. So during the Christmas holiday, a day has been organised during which the inhabitants of Diepenveen will be asked whether they may have, perhaps somewhere in their attic, some material or documents that could shed some more light on this extraordinary discovery.

Scientific collection

In the meantime, on the 12th December 2013 at 11:30 a.m., the meteorite’s former owner, Mrs L. Kiers, presented the ‘Diepenveen’ to the Director of Naturalis Biodiversity Center, Edwin van Huis. As part of Naturalis' scientific collection, the rock will still be accessible for further research and it will also be officially included on the international list of meteorites. In exchange for the Diepenveen, Mrs Kiers will be given a piece from a similar sort of meteorite, ‘the Allende.’

Meteorite weekend in January

The Diepenveen, together with the four other Dutch meteorites, are on view to the public at Naturalis for just one weekend: the 18th and 19th January 2014. During that weekend, the scientists involved with this discovery will tell their story and hold a workshop called ‘How to recognise a meteorite.’ People can then also bring their own discoveries for examination by the experts. A detailed programme for this weekend will soon be available here (in Dutch).
More extensive background information about the Diepenveen and the other Dutch meteorites can be found here (in Dutch).

Quelle: Naturalis


2452 Views

Freitag, 13. Dezember 2013 - 21:00 Uhr

Astronomie - Kosmologen uneins über mysteriöse Anomalien in den Daten von frühen Universum

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Planck satellite's picture of cosmic microwave background needs correction, some researchers argue.

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The Planck probe's picture of the full sky — which it took in different bands of the microwave spectrum —  may have been plagued by systematic errors in the 217-gigahertz band, a new study suggests.

ESA and the Planck Collaboration

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A new analysis of data on the infant universe released earlier this year indicates that the initial findings are more in line with the standard cosmological picture than had originally been thought.

There were both celebrations and surprises last March when the science team of the European Space Agency’s Planck mission unveiled a new map of the cosmic microwave background (CMB), the radiation left over from the Big Bang. The precision data formed the highest-resolution all-sky CMB map ever. And it revealed a higher density of matter, a slightly greater variation in the distribution of that matter, and a lower value of the Hubble constant — a measure of the Universe's expansion rate — than a host of previous studies from the ground and space had indicated.

Although the differences were slight, cosmologist David Spergel of Princeton University in New Jersey was intrigued. “Planck is so precise that even small discrepancies become interesting,” he notes. The initial findings, he says, suggested one of three possibilities: Either the standard cosmological model might have to be modified; or a host of different astronomical studies were incorrect; or some systematic error in the Planck data had not been accounted for.

A new analysis of the Planck data by Spergel, Renée Hložek of Princeton and Raphael Flauger of the Institute for Advanced Study in Princeton and New York University indicates that the problem lies with the Planck sky map data recorded at a radio frequency of 217 gigahertz. When they removed the 217-GHz data from the maps and relied on two lower frequencies, 100 and 143 GHz, the results essentially fell in line with previous CMB and other astrophysical studies, including NASA's Wilkinson Microwave Anisotropy Probe (WMAP). Spergel had led the analysis for that mission.

Spergel presented the findings on 10 December at the 27th Texas Symposium on Relativistic Astrophysics in Dallas. He and his collaborators also posted the study on the arXiv preprint server2.

In one of the Planck team’s many research papers released in March, the scientists noted that the data recorded at 217 GHz failed some calibration tests1. However, the method that the Planck team chose to analyse the data did not account for this issue.

Spergel and his team also compared Planck data recorded during the first half to that taken during the second half of the craft’s observing seasons. That comparison revealed that the 217-GHz data were not independent of data gathered at other frequencies. When Spergel’s team corrected for the correlation they found, the cosmological properties deduced from the Planck sky maps were also more similar to those calculated from earlier studies. Detectors at different frequencies might not be independent because they are all housed in the same cooling system, Spergel suggests.

The Planck researchers acknowledge that a systematic error might have been at play, and they say that they will now re-examine their own data analysis, which is currently under review at a journal, says Francois Bouchet, a Planck researcher from the Institute of Astrophysics of Paris.

However they also stand by their earlier claim. "We believe that differences in cosmological parameters derived by WMAP and Planck are not due to [the spurious 217 GHz] feature, but more simply to the improved performance of the Planck data," says ESA's Jan Tauber, who leads the Planck science team and is based in Noordwijk,The Netherlands.

“There is an issue with one set of detectors on Planck, which we were aware of, but didn't properly understand by the time of the 2013 data release,” adds George Efstathiou, an astrophysicist at the University of Cambridge, UK, and another member of the Planck science team. “It is a small systematic and has very little impact on the cosmology, but it is a systematic that will be removed from the 2014 data,” he says.

“With an experiment as sensitive as Planck, the great challenge is fully understanding all of the systematics,” says Spergel.  He adds that just as the analysis of WMAP data continued to improve through its nine years of operations, “I anticipate that the Planck 2014 analysis will be an improvement on the Planck 2013 analysis.”

Cosmologist Michael Turner of the University of Chicago in Illinois quips, “Precision cosmology is hard; accurate cosmology is even harder.”

Quelle: nature


2657 Views

Freitag, 13. Dezember 2013 - 13:11 Uhr

Raumfahrt - China´s Change3-Mond-Rover Mission Teil-1

 

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5.05.2013

The proposed Chang’e 3 rover, scheduled for launch in December 2013.

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Currently scheduled for launch in December 2013 from the Xichang Satellite Launch Center in Sichuan province, the Chang’e 3 mission aims to land a Chinese rover on the Moon. If the mission is successful, it will be the first soft landing on the Moon since the Russian Luna 24 mission in 1976. Overseen by the China National Space Administration, the Chang’e program is following a step-wise approach to lunar exploration that could lead to the first taikonaut stepping onto the Moon by 2025.

The previous Chang’e 1 and 2 lunar orbiting missions, launched in 2007 and 2010, represented the first phase of the Chang’e program. Chang’e 3, to be followed by Chang’e 4, represent the second phase of the program, both involving rovers. The third phase, with Chang’e 5, will be a sample-return mission and is currently scheduled for 2017. After that, it is anticipated that a new program will commence, which might culminate in a manned landing.

Chang’e is the name of a Chinese goddess who ascended to the Moon after consuming an immortality pill and there befriended a jade rabbit who was already a lunar resident. The elements of this legend were relayed by NASA to the Apollo 11 crew ahead of the first Moon landing in 1969. Michael Collins famously responded “Okay. We’ll keep a close eye out for the bunny girl.”

The Chang’e 3 lander will set down in Sinus Iridum, which is an extension of Mare Ibrium and roughly opposite the Apollo 15 landing site near Hadley Rille.

After landing, a solar-powered rover will roll off the lander and commence its mission, which is expected to last for at least three months, although presumably that will include a lot of down-time while the two-week-long lunar nights prevail.

The Chang’e 3 lander itself will continue to operate as a stationary science platform. It will be powered by a radioisotope thermoelectric generator and hence will be largely unaffected by the presence or absence of direct sunlight. The lander will operate a number of science instruments, including an optical telescope and a “soil probe” to conduct analyses of lunar regolith.

The Chang’e 3 rover will have a mass of 120 kilograms, including a 20 kg science payload. It is reported that it will explore widely over an area within a 5 kilometer radius of the lander. This sounds a little ambitious considering that the Spirit and Opportunity rovers traveled just 2 to 3 kilometers over their first year of operation, but the Chang’e 3 rover will have more advanced technology and more solar energy to draw upon.

The rover will also have autonomous hazard avoidance and navigation capacity, but with a radio delay of only 1.3 seconds from Earth, it will be mostly under the direct control of an Earth-based driver.

The rover’s science payload will include an alpha particle X-ray spectrometer, which has been standard issue on all the NASA Mars rovers to date, to enable geochemical analyses. The rover will also have a radar device on its underside, to investigate the structure and depth of the lunar regolith as well as the underlying structure of the lunar crust.

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Quelle: AS

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Update: 25.09.2013

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China unveils its first and unnamed moon rover
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BEIJING, Chinese scientists described the country's first moon rover on Wednesday and invited the global public to come up with a name for it.
Zhao Xiaojin, director of the aerospace department of the China Aerospace Science and Technology Corporation, depicted the lunar rover an orbiter adaptable to harsh environments; a highly efficient and integrated robot; and a high altitude "patrolman" carrying the dreams of Asia.
The Chang'e-3 mission to moon, named after a Chinese lunar goddess, will take place in December, when a Chinese spacecraft will soft-land on a celestial body for the first time.
The rover has two wings, stands on six wheels, weighs 140 kg and will be powered by solar energy.
"When it arrives in lunar orbit on board a lander, the rover will choose the best landing site and gently touch down the moon's surface, using optical and microwave sensors to avoid rocks and craters," Zhao said.
The rover will "select the best route, use minimal fuel and make the smallest possible error" during landing and is capable of hovering to steer clear of obstacles, he said.
Domestic and overseas compatriots can submit their proposed names for the rover through the Internet and the official name will be announced in November after an online poll on the selected proposals.
Li Benzheng, deputy chief designer of China's lunar probe program, said the name of the rover should express the wishes of Chinese at home and abroad, feature the modern and national traits to inspire people.
Li noted the rover will recognize obstacles on the moon's surface, and plot a path of least resistance by a combination of onboard navigation systems and remote control from the command center.
The rover can "rest", automatically entering a dormant state to recharge its batteries, and return to work after a while, Li said.
It can endure a vacuum, intense radiation and extremes of temperature. Temperatures on the moon's surface can range from minus 180 to plus 150 degrees Celsius, said Wu Weiren, the program's chief designer.
The rover is equipped with numerous detectors and information gathering systems such as a panoramic camera and radar measurement devices. The rover will patrol the Earth's natural satellite for about three months.
The data collected by the rover, such as 3D images, infrared spectrums and lunar soil analysis, will directly and accurately lead to greater understanding of the moon..
China launched Chang'e-1 in 2007 and Chang'e-2 in 2010. The first probe collected a large body of data and a completed map of the moon. The second mission greatly enhanced the resolution of the previous map and generated a high-definition image of Sinus Iridium, a plain of basaltic lava, considered by lunar observers to be one of the satellite's most beautiful features.
The Chang'e-3 moon probe is part of the second stage of China's three-stage lunar mission, orbiting, landing, and analyzing lunar soil and stone samples.

Quelle: Xinhua

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Update: 28.10.2013

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Chinese lunar rover looks too much like Nasa's Opportunity, say scientists

 

Chinese design plays it safe but ends up looking too much like Nasa's Mars vehicle

Chinese lunar rover looks too much like Nasa's Opportunity, say scientists

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The launch of China's most ambitious lunar probe, scheduled for sometime in December, will likely be a proud moment for many in the nation.
But for some scientists, at least one of whom was directly involved in the project, the event will be frustrating.
The rover, they say, shows little technological innovation, and borrows heavily from American and Soviet-era designs.
The rover, they note, looks similar to Nasa's Opportunity, which has roamed Mars for nearly a decade. Both feature a flat back with solar panels, a long neck fronted by cameras and a robotic arm set at the front chest.
Only their wheels are different. For that part, the Chinese rover seems to have borrowed heavily from the Lunokhod 1 - the first lunar rover launched by the Soviet Union in 1970.
Some scientists directly involved in the rover design project said the Chinese version was derivative.
"There is no denying the similarities," Professor Wen Guilin from Hunan University in Changsha told the South China Morning Post.
Wen said the Chinese vehicle "borrowed heavily from other countries, in particularly the United States".
"A lot of things have been drawn from the reliable and successful design of the [American] Mars rover," he said.
If the Chinese design lacks originality, it is not for want of trying. In 2005, the government asked all qualified universities and institutes to propose designs for the rover. It said the winner would be chosen through a fair, transparent process.
It was the first time that the secretive space agency - run by the military - had invited civilian scientists to participate in a major exploration programme.
Many top universities set up special teams of their best researchers, who proposed creative rover designs. Wen's own team, for instance, offered a design with only four wheels but with a greater ability to manoeuvre over rough terrain.
Civilian scientists were disappointed when authorities decided on a design they felt drew heavily on the American design.
Zhu Jihong, a professor of robotics who entered the competition on behalf of Tsinghua University, said the outcome had dampened Chinese scientists' enthusiasm for innovation.
"In the beginning they said they encouraged original thinking. In the end they did not even bother to make an announcement or give us any feedback," he said. "We will not participate in anything that involves the military in the future."
Professor Cao Qixin, whose team from the Jiaotong University in Shanghai submitted a spider-like design, said he was not surprised by the decision.
Unlike the space programmes in the US and other Western countries, China's programme was not focused on pushing technological limits, Cao said.
"You see other countries have failed in their space programmes. But Chinese missions are almost always perfect," he said, "We only trust tried and proven technology and equipment. They may not be advanced, but they guarantee you success."
Wen, however, defended the government's design decision. "This is a big project, where creativity has to give way to practicality," he said.
Quelle: South China Morning Post
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Carrier rocket sent to launch base for unmanned moon landing mission
A Long March-3B carrier rocket is being transported towards the Xichang Satellite Launch Center in southwest China, after left Beijing Sunday morning, to prepare for the upcoming launch of Chang'e-3 moon probe.
The carrier rocket left the capital aboard a train and is scheduled to reach the launch center on Nov. 1, said a statement from the State Administration of Science, Technology and Industry for National Defense.
Compared with the carrier rocket of Chang'e-2 moon probe, this one has been equipped with a number of new technologies and its reliability has been further improved, the statement said.
All tests on the Chang'e-3 moon probe, which has been in Xichang since Sept. 12, are going on smoothly, the statement added.
The Chang'e-3 moon probe is designed to carry China's first moon rover and soft-land on the moon. Its launch is scheduled at the end of this year.
It is part of the second stage of China's three-stage lunar probe program, orbiting, landing, and analyzing lunar soil and stone samples.
Quelle: CHINAS-NEWS
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Ten candidate names for China's first moon rover after global poll
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Ten possible names for China's first moon rover, likely to be launched in December, have come out after a month-long online poll and debate of a jury board.
"Yutu," or jade hare in Chinese, tops the list while "Tansuo," or explore, and "Lanyue," or catch moon, came at the second and third places, said Sunday's Beijing Times.
Chinese at home and abroad were wooed to submit proposals for the name of the lunar rover at www.xinhuanet.com and www.qq.com from Sept. 25 to Oct. 25.
About 190,000 proposals were received and a 14-member jury board selected the ten most popular after heated debates and several rounds of vote on Saturday, said the newspaper report.
Yutu is a white pet rabbit accompanying the goddess Chang'e on the moon in a popular ancient Chinese myth.
In the next week, another online poll will elect the three most popular names and the final result will be announced in November.
The moon rover is scheduled to be on board of the Chang'e-3 moon probe, which will soft-land on the moon.
The rover has two wings, stands on six wheels, weighs 140 kg and will be powered by solar energy.
In an interview last month, Zhao Xiaojin, director of the aerospace department of the China Aerospace Science and Technology Corporation, depicted the lunar rover an orbiter adaptable to harsh environments; a highly efficient and integrated robot; and a high altitude "patrolman" carrying the dreams of Asia.
"When it arrives in lunar orbit on board a lander, the rover will choose the best landing site and gently touch down the moon's surface, using optical and microwave sensors to avoid rocks and craters," Zhao said.
The Chang'e-3 moon probe is part of the second stage of China's three-stage lunar mission, orbiting, landing, and analyzing lunar soil and stone samples.
Quelle: Xinhua
 

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Update: 22.11.2013 

China's 1st Moon Lander May Cause Trouble for NASA Lunar Dust Mission

China's mission to robotically land on the moon next month is sure to stir up lunar dust, but it may also cause a political dustup, too.
China is in the final stages of preparing its robotic Chang'e 3 moon lander to launch atop a Long March 3B rocket, slated for liftoff in early December. The ambitious mission is built to first orbit the moon, then propel down to a landing site, after which a small, solar-powered lunar rover will be unleashed.
Already on duty orbiting the moon is NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE). The probe's science instrument commissioning is now underway, after which the spacecraft will drop down to the lower lunar science orbit and start the full science phase of the mission.
LADEE is designed to study the moon's thin exosphere and the lunar dust environment. However, there is concern that China's ambitious Chang'e 3 mission could impact LADEE's science goals.
Significant contamination
"The arrival of the Chang'e 3 spacecraft into lunar orbit and then its descent to the surface will result in a significant contamination of the lunar exosphere by the propellant," saidJeff Plescia, a space scientist at Johns Hopkins University's Applied Physics Laboratory in Laurel, Md.
Plescia also chairs NASA's Lunar Exploration Analysis Group (LEAG), chartered to assist the space agency in planning the scientific exploration of the moon.
While Chang'e 3's mission will create some problems for LADEE — in that the spacecraft would measure not only the native exosphere, but also the Chinese spacecraft's propellant — it also creates a unique opportunity, Plescia told SPACE.
Sinus Iridum area of the moon. It is likely that China will land a rover near Laplace A crater. Arrow shows location of Soviet Lunokhod 1 rover. 
Credit: NASA/GSFC/Arizona State University
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"Propellant will be released at a relatively high altitude from burns as the Chang'e spacecraft enters lunar orbit and then at a range of altitudes as the spacecraft descends to the surface," Plescia said. "LADEE will be able to observe how the propellant becomes distributed into the lunar exosphere and then how it is later removed."
LADEE also has the potential to measure dust that might be lofted above the lunar surface by the Chang'e 3 touchdown, he said.
That big nozzle on the bottom of the Chinese lander, Plescia said, should produce a significant plume on the surface. "We see plume effects at every landing site, human and robotic," he said.
Wanted: scientific cooperation
Clive Neal of the Department of Civil & Environmental Engineering and Earth Sciences at the University of Notre Dame in Indiana has a similar point of view.
It is possible that Chang'e 3 could severely compromise the LADEE mission, Neal told SPACE.com. That's because LADEE is slated to establish a baseline evaluation of the moon's exosphere, something that may not be completed by China's robotic landing, Neal said.
"Conversely, with some sort of communication between the missions, including NASA's Lunar Reconnaissance Orbiter (LRO)," talk between countries could enhance both LADEE and Chang'e 3 investigations, Neal said.
"What we have here is a situation where politics is certainly inhibiting good scientific cooperation and discovery because the NASA mission people are not allowed to communicate bilaterally with their Chinese counterparts," Neal said.
Landing site
High-definition images of what appears to be the preferred landing spot for Chang'e 3 — called Sinus Iridum — were snapped by China's Chang'e 2 lunar orbiter in late 2010.
Meanwhile, China's state-run Xinhua News agency has been hosting an online poll, calling on the public to select the rover's name, with "Seeking Dream" in the lead after more than 500,000 votes.
The six-wheeled rover is equipped with four cameras and can climb onto hills and cross over obstacles on the moon's surface, Xiao Jie, a designer for the rover with the Shanghai Academy of Spaceflight Technology, said according to Xinhua.
The rover will patrol the surface for at least three months under control by scientists on Earth, said Ye Peijian, chief commander of the Chang’e-2 and Chang’e-3 missions, according to the Xinhua.
Great place to rove
Mark Robinson of Arizona State University's School of Earth and Space Exploration is eagerly awaiting China's first lunar landing attempt. Robinson is the Lunar Reconnaissance Orbiter Camera (LROC) Principal Investigator on NASA's Lunar Reconnaissance Orbiter.               
If indeed China's lander/rover successfully digs its legs into and rolls around Sinus Iridum, Robinson said the site is "a great place to rove!"
Robinson added that the exact landing spot has not officially been announced, but it seems likely the landing will take place in Sinus Iridum, near the fresh crater Laplace A, a feature 5 miles (8 kilometers) in diameter.
If so, the Chinese moon machinery won't be alone.
The Soviet Union's Luna 17/Lunokhod 1 rover landed nearby in November 1970 and is 155 miles (250 km) Southwest of Laplace A.The now-stilled Lunokhod was on the prowl for 11 months, relaying views of the lunar landscape to Earth and carrying out soil tests.
Why Sinus Iridum?
It is likely that there are critical engineering constraints in terms of landing site selection as well as important science goals, Robinson told SPACE.com. An added bonus, he said, is that there is the sheer grandeur view from the rim of Laplace A.
The Chinese rover would get an eyeful rolling up to that rim. It's a sheer drop of more than 5,200 feet (1,600 meters).
From LROC narrow-angle cameras, scientists can tell that the crater sports solid material exposed in the upper walls and has seen dramatic landslides that have streamed material down to the crater floor.
The crater floor hosts a now-frozen lake of impact melt 1.5 miles (2.4 km) in diameter, Robinson said.
Inviting ejecta blanket
Wheeling around the area, the rover will traverse the crater's ejecta blanket, Robinson said, so in a geologic sense, the robot can drive "down" into the crater. Material ejected from deep in the crater ends up near the rim, he said, and rocks from the preimpact surface are thrown far from the crater.
So as a rover drives ever-closer to the rim, it can characterize rocks from deeper and deeper below the surface, Robinson said.
"No humans or robots have ever visited a fresh crater anywhere near this size on the moon — or Mars for that matter — so the return from this mission has great potential for advancing our knowledge of the moon," Robinson said.
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The Chang’e 3 lunar lander and moon rover is part of the second phase of China’s three-step robotic lunar exploration program.
Credit: Beijing Institute of Spacecraft System Engineering
Quelle: SpaceInsider

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Update: 26.11.2013

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China´s lunar probe to land on moon next month 

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Wu Zhijian (C), spokesman with the State Administration of Science, Technology and Industry for National Defense, introduces China's lunar probe at a press conference in Beijing, capital of China, Nov. 26, 2013. China is scheduled to launch Chang'e-3 lunar probe to the moon in early December, marking the first time for a Chinese spacecraft to soft-land on the surface of an extraterrestrial body, the official said Tuesday.

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China is scheduled to launch Chang'e-3 lunar probe to the moon in early December, the first time a Chinese spacecraft will soft-land on the surface of an extraterrestrial body, an official said Tuesday.

 

Chang'e-3 comprises a lander and a moon rover called "Yutu" (Jade Rabbit). The lunar probe will land on the moon in mid-December if everything goes according to plan, said Wu Zhijian, spokesman with State Administration of Science, Technology and Industry for National Defence(SASTIND).

 

Tasks for Yutu include surveying the moon's geological structure and surface substances, while looking for natural resources, Ouyang Ziyuan, chief scientist of China's lunar orbiter project, said in an interview with Xinhua.

 

Yutu will land in Sinus Iridum, or the Bay of Rainbows, and operate there for three months. It can travel at a speed of 200 meters per hour.

 

The Bay of Rainbows was selected because the level terrain will enable smooth communication and ample sunshine. Previous lunar missions were near the lunar equator and no country has surveyed the area yet. The Bay of Rainbows was "left blank" in the study of the moon, said the scientist.

 

The Chang'e-3 mission is the second phase of China's lunar program, which includes orbiting, landing and returning to Earth. It follows the success of the Chang'e-1 and Chang'e-2 missions in 2007 and 2010.

 

Chinese scientists have made technological breakthroughs for Chang'e-3, which will be the most complicated and difficult task in China's space exploration, SASTIND spokesman Wu said.

 

"More than 80 percent of the technology adopted in the mission is new," he said.

 

The mission will be China's first exploration of an extraterrestrial object using remote control of a lunar probe and deep space communication, Wu said.

 

Narrow time windows mean a timely launch is essential. Different trajectory parameters have to be adapted quickly as intervals between the windows are very short, he said.

 

Many technologies will be used to ensure the probe makes a soft-landing in low-gravity conditions. The rover will separate from the lander to the explore area around the landing site.

 

The lunar program will also see breakthroughs in remote control between the moon and Earth. Technologies of high precision observation and control as well as lunar positioning will be used in the mission, which includes experiments that would be extremely difficult to conduct on Earth's surface, he said.
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Quelle: Xinhua
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China names moon rover "Yutu"
              
China has chosen the name "Yutu" (Jade Rabbit) for its first moon rover, after a worldwide online poll challenged people to come up with names.
Li Benzheng, deputy commander-in-chief of China's lunar program, announced the name at a press conference on Tuesday.
"Yutu is a symbol of kindness, purity and agility, and is identical to the moon rover in both outlook and connotation. Yutu also reflects China's peaceful use of space," said Li.
In Chinese folklore, Yutu is the white pet rabbit of Chang'e, the moon goddess who has lent her name to the Chinese lunar mission.
Legend has it that, after swallowing a magic pill, Chang'e took her pet and flew toward the moon, where she became a goddess, and has lived there with the white jade rabbit ever since.
From Sept. 25 to Oct. 25, Chinese at home and abroad were invited to submit proposals for the rover's name on two websites. About 190,000 proposals were received and a 14-member jury selected the ten most suitable after heated debate.
Popular names included "Tansuo" (Explore) and "Lanyue" (Catch the Moon), according the Beijing Times. Another popular choice was "Qian Xuesen," the late scientist who is considered the father of China's space program.
In the final round of voting, about 650,000 people out of more than 3.4 million chose Yutu, according to Li.
The moon rover is part of the Chang'e-3 lunar probe, which is expected to be launched in early December. The mission is the second phase of China's lunar program, which includes orbiting, landing and returning to Earth.
Yutu is scheduled to land on the moon in the middle of December and explore the surface for three months.
If successful, it will be the first time a Chinese spacecraft has soft-landed on the surface of an extraterrestrial body.
The rover has two wings, stands on six wheels, and weighs 140 kg. It is a highly efficient and integrated robot that can withstand the vast temperature variations of the moon.

 Quelle: China News

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Update. 28.11.2013

 

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Chinese moon lander on the verge of launch

China has scheduled the launch of an ambitious robotic lunar rover as soon as Sunday on a quest to achieve the first soft landing on the moon in more than three decades.
The Chang'e 3 mission is China's third moon probe, following two successful orbiters that surveyed the lunar surface and mapped landing zones.
Chinese officials say the mission is set for launch in early December, with landing on the moon scheduled for mid-December. China has not officially disclosed the mission's launch or landing dates.
But an aeronautical notice issued to warn pilots of an impending launch indicates the solar-powered rover is set for liftoff Sunday shortly after 1720 GMT (12:20 p.m. EST) from the Xichang space center in southwestern China's Sichuan province.
The launch will come in the middle of the night in China at approximately 1:20 a.m. Beijing time.
A Long March 3B rocket will boost the probe on course toward the moon, where the spacecraft will enter orbit five days after launch before dropping to the lunar surface for landing some time in mid-December, according to Wu Zhijian, a spokesperson for China's State Administration of Science, Technology and Industry for National Defence, or SASTIND, which is managing the Chang'e 3 mission.
The mission is China's first try to land a spacecraft on the moon - or any other celestial body - and it marks a new phase in the country's exploration efforts, which include a lunar sample return mission before the end of the decade.
The lander reportedly weighs about 3,800 kilograms, or about 8,377 pounds, fully loaded with propellant. It's dimensions measure a bit larger than a sports utility vehicle.
Quelle: SN
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Update: 29.11.2013
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ESA hilft China zum Mond
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Kourou tracking station
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Shortly after China’s Chang’e-3 spacecraft departs Earth to land on the Moon, ESA’s network of tracking stations will swing into action, providing crucial support for the vessel’s five-day lunar cruise.

China’s Chang’e-3, named after the mythological goddess of the Moon, is scheduled for lift off on 1 December from the Xichang launch base in China’s Sichuan province on a journey to deposit a lander and a six-wheeled rover on the lunar surface.

The landing, in the Sea of Rainbows on 14 December, will be the first since Russia’s Luna-24 in 1976.

Immediately after liftoff, ESA’s station in Kourou, French Guiana, will start receiving signals from the mission and uploading commands on behalf of the Chinese control centre.

The tracking will run daily throughout the voyage to the Moon. Then, during descent and after landing, ESA’s deep-space stations will pinpoint the craft’s path and touchdown. 

“We are proud that the expertise of our ground station and flight dynamics teams and the sophisticated technologies of our worldwide Estrack network can assist China to deliver a scientifically important lander and rover to the Moon,” says ESA’s Thomas Reiter, Director for Human Spaceflight and Operations.

“Whether for human or robotic missions, international cooperation like this is necessary for the future exploration of planets, moons and asteroids, benefitting everyone.”

The effort is being run from the Estrack Control Centre in ESA’s European Space Operations Centre in Darmstadt, Germany.

Chang’e-3 liftoff is set for around 18:00 GMT on 1 December, and the 15 m-diameter dish in Kourou will pick up the first signals around 18:44 GMT.

Working with Chinese tracking stations, Kourou will support the mission through lunar orbit entry on 6 December continuing until just prior to its descent to the surface, expected around mid-day on 14 December.

The landing and rover operations on the Moon will be commanded via two Chinese tracking stations at Kashi, in the far west of China, and at Jiamusi, in the northeast.

“After the lander and rover are on the surface, we will use our 35 m-diameter deep-space antennas at Cebreros, Spain, and New Norcia, Australia, to provide ‘delta-DOR’ location measurement,” says Erik Soerensen, responsible for external mission tracking support at ESOC.

“Using this delta-DOR technique, you can compute locations with extreme accuracy, which will help our Chinese colleagues to determine the precise location of the lander.”

Together with Cebreros, New Norcia will record Chang’e-3’s radio signals during landing, which will help the Chinese space agency to reconstruct the trajectory for future reference.

A team of engineers from China will be on hand in Darmstadt. “While we’re very international at ESOC, hardly anyone speaks Mandarin, so having Chinese colleagues on site will really help in case of any unforeseen problems,” says Erik.

“Both sides are using international technical standards to enable our stations and ESOC to communicate with their mission and ground systems."

Quelle: ESA

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Update: 30.11.2013
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China will send a rabbit rover to the moon this weekend

China may soon become the world's third country to land an object on the surface of the Moon — and a bunny will be along for the ride. On Tuesday, the country voted to name its new lunar rover Yutu, or Jade Rabbit, out of 190,000 proposed ideas. The choice of name shouldn't be a surprise. On Sunday, December 1st at 17:30 GMT, the superpower will send the rover to the moon on board its Chang'e-3 lunar probe. In Chinese folklore, Chang'e was a goddess who accidentally swallowed an immortality pill and flew to the Moon, with only a rabbit to keep her company.

"Yutu is a symbol of kindness, purity and agility, and is identical to the moon rover in both outlook and connotation. Yutu also reflects China's peaceful use of space," said Li Benzheng, deputy commander-in-chief of China's lunar program, at a press conference announcing the naming choice.

Chang'e-1 and Chang'e-2 were merely lunar orbiters, and the primary goal of Chang'e-3 is to achieve a soft landing on the moon. Should all go well, Chang'e and Yutu should arrive on the Moon around December 14th, landing in a plain known as the Sea of Rainbows. After that, the six-wheeled rover will spend three months exploring for resources.

China's space program is advancing rapidly, with the country intending to put men on the moon and build a space station of its own before long. However, Chinese officials say they don't intend to provoke another space race, according to a translation at The Planetary Society.

In fact, we have no desire to race with any country. China has its own space program. We are realizing our own plans step by step. Our goal is to use space peacefully. It is also the consensus of the world. Human beings need to make use of space resources to support sustainable development.

Amusingly, the crew of Apollo 11 were asked to look for Chang'e and her rabbit companion as they were about to land on the moon way back in 1969. "We'll keep a close eye out for the bunny girl," replied astronaut Michael Collins at the time.

Quelle: The Verge

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Update: 1.12.2013 

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The launching tower where the Chang'e-3 lunar probe has been ready for being launched is loaded with fuel at the Xichang Satellite Launch Center, southwest China's Sichuan Province, Nov. 30, 2013. China will launch the Chang'e-3 lunar probe to the moon at 1:30 a.m. Monday. It will be the first time for China to send a spacecraft to soft land on the surface of an extraterrestrial body, where it will conduct surveys on the moon.

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The weather at the launch site for China's Chang'e-3 lunar probe will be favorable, a senior engineer with Xichang Satellite Launch Center has said.
Jiang Xiaohua, a senior meteorologist, told Xinhua on Sunday that the weather will be good for the window period for the launch. There will be no rain.
Jiang said cold weather and upper winds may pose challenges as temperature variations will affect the decision on how much fuel will be needed. Strong winds may influence the rocket's trajectory.
China will launch Chang'e-3 lunar probe to the moon at 1:30 a.m. Monday from the launch center.
It will be the first time China has sent a spacecraft to soft land on the surface of an extraterrestrial body.
Quelle: Xinhua

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Update: 18.45 MEZ 
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The Chang'e 3 lunar probe, now getting ready for its launch at 1:30 a.m. on Dec. 2, is set to accomplish several unprecedented achievements.
It will be a global first to simultaneously land on the moon and carry out both a patrol and surveillance.
Chang’e 3 will be the first Chinese spacecraft to make a soft landing on the surface of any extraterrestrial body.
Additionally, it will be the first Chinese spacecraft to carry out both a a patrol and surveillance in extraterrestrial territory.
Chang'e 3 will be the first Chinese spacecraft to employ radioisotope heat source technology as well as conduct a two-phase fluid loop.
The lunar probe will mean the first breakthrough in the technologies of multiple-window of cryogenic propellant rockets, narrow launch width and high-precision orbiting.
It will for the first time to study and develop a large-scale Chinese deep-space station and set up a deep-space measurement and control network.
It is the first time a remote control will be used on a lunar probe.
It is the first time a lunar probe will research and build a set of high-level experimental facilities and create a set of advanced experimental methods.
Finally then, it is the world’s first lunar probe to carry out multiple scientific research on the moon.
Quelle: China.org
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A Long March 3B rocket launches with China's 'Yutu' moon rover from the Xichang Satellite Launch Center, Dec. 1, 2013. (Xinhua)
December 1, 2013 — China's first lunar rover is bound for the moon, having launched Sunday (Dec. 1) on a mission that, if successful, will establish China as the third nation to soft land a spacecraft on Earth's natural satellite.
China's Chang'e 3 probe, with its "Yutu" moon rover, lifted off at 11:30 a.m. CST (1730 GMT; 1:30 a.m. Dec. 2 local time) on top of a Long March 3B rocket from the Xichang Satellite Launch Center in the country's southwest region.
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Moonshot to test rover’s soft-landing
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Update: 2.12.2013

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ESA BODENSTATIONEN UNTERSTÜTZEN CHINESISCHE MONDMISSION 

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Kurz nachdem Chinas Sonde „Chang'e-3“ die Erde verlassen hat, um auf dem Mond zu landen, hat sich das Bodenstationsnetzwerk der ESA an die Arbeit gemacht, unverzichtbare Unterstützung für den fünftägigen Flug zum Mond zu liefern.
Die MissionChang'e-3, benannt nach der Mondgöttin Chang’e aus der chinesischen Mythologie, ist am 1. Dezember um 18:30 MEZ vom Weltraumbahnhof Xichang LC-2 in der chinesischen Provinz Sichuan gestartet. Die Raumsonde wird eine stationäre Basis und einen sechsrädrigen Rover auf der Mondoberfläche positionieren.
Die Landung an der Regenbogenbucht (Sinus Iridum) ist für den 14. Dezember geplant und wird die erste weiche Mondlandung seit der russischen Mission „Luna 24“ im Jahr 1976 sein.
Unterstützung durch europäische Funkstation
Unmittelbar nach dem Start hatte die 15-Meter-Antenne der ESA-Bodenstation in Kourou, Französisch-Guayana, mit der Unterstützung der Telekommunikation begonnen. Sie hat Signale der Mission empfangen und als Schnittstelle zur chinesischen Kontrollstation Telekommandos fungiert.
Dieser Funkkontakt wird täglich stattfinden und über den kompletten Flug zum Mond andauern. Während des Anflugs und nach der Landung werden die ESA-Weltraumstationen eingesetzt, um akkurate Positionsbestimmungen zu liefern. 
Alle Aktivitäten werden von der Steuerungszentrale des ESA-Bodenstationsnetzes ESTRACK im Europäischen Satellitenkontrollzentrum ESOC in Darmstadt aus kontrolliert.
„Wir sind stolz darauf, dass die Kompetenz unserer Bodenstation und das Fachwissen unseres Flugdynamik-Teams sowie die hochentwickelte Technologie unseres weltweiten ESTRACK-Netzwerkes China dabei helfen können, einen wissenschaftlich bedeutenden Lander und einen Rover zum Mond zu bringen“, sagt Thomas Reiter, Leiter des ESA-Direktorats für Bemannte Raumfahrt und Missionsbetrieb.
„Ob für bemannte oder robotergesteuerte Missionen, solche internationalen Kooperationen sind für die zukünftige Erforschung von Planeten, Monden und Asteroiden notwendig und nutzen der Allgemeinheit.“
Der Start der Chang’e-3-Mission ist am 1. Dezember um18:30 Uhr MEZ  erfolgt. Die Station in Kourou hat die ersten Signale um 19:34 Uhr MEZ empfangen.
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ESTRACK-Kontrollraum am ESOC in Darmstadt/GERMANY
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In Abstimmung mit chinesischen Funkstationen wird das Zentrum in Kourou die Mission beim Eintritt in die Mondumlaufbahn am 6. Dezember bis zum Anflug der Sonde auf die Mondoberfläche, der um die Mittagszeit am 14. Dezember erwartet wird, unterstützen.
Die Mondlandung und die Roveroperationen auf der Oberfläche werden über die chinesischen Stationen Kashi und Jiamusi kontrolliert.
„Nachdem der Lander und der Rover auf der Mondoberfläche angekommen sind, werden unsere Raumstationen in Cebreros, Spanien, und New Norcia, Australien, die mit 35-Meter-Antennen ausgestattet sind, Standortbestimmungen mit delta-DOR-Technologie durchführen“, sagt Erik Soerensen, zuständig für die Unterstützung externer Missionsverfolgung am ESOC.
„Mit der delta-DOR-Technologie können Standorte äußerst präzise berechnet werden. Das wird unseren chinesischen Kollegen dabei helfen, die exakte Position des Landers zu lokalisieren.“
Station in New Norcia beobachten die Mondlandung
Die Stationen in New Norcia und Cebreros werden die Chang’e-3-Radiosignale während der Landung aufzeichnen. Diese Aufzeichnungen werden der chinesischen Raumfahrtbehörde helfen, die Flugbahn für zukünftige Anwendungen zu rekonstruieren.
Während der Unterstützungsaktivitäten wird ein chinesisches Ingenieur-Team in Darmstadt stationiert sein.
„Beide Seiten nutzen internationale technische Standards, sodass unsere Stationen und das ESOC mit ihrer Mission und ihren Experten am Boden kommunizieren können“, sagt Soerensen.
„Wir sind am ESOC sehr international aufgestellt. Dennoch haben wir kaum Mitarbeiter, die Mandarin sprechen. Im Fall von unerwarteten Problemen wird es also sehr hilfreich sein, die chinesischen Kollegen vor Ort zu haben.“
Quelle: ESA
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Update: 3.12.2013
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Chang'e-3 trims its orbit
               
BEIJING, Dec. 2 (Xinhua) -- Chang'e-3, China's first planned soft moon landing, finished the first orbital trimming at 3:50 p.m. in its trajectory along the earth-moon transfer orbit, the Beijing Aerospace Control Center (BACC) said.
Chang'e-3 mission with moon rover "Yutu" (Jade Rabbit) was successfully launched early on Monday morning from the Xichang Satellite Launch Center.
It will travel for around 112 hours along the earth-moon transfer orbit, while scientists adjust its orbit depending on the circumstances.
The probe is estimated to reach the 100-km high circular lunar orbit sometime on Friday.
The BACC said as of 4:00 p.m. Beijing Time on Monday, Chang'e-3 has been flying for about 14 hours and is now about 138,000 km away from Earth.
Quelle: Xinhua
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Update: 6.12.2013
 

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Planned orbit trim for Chang'e-3 canceled

Chinese lunar probe Chang'e-3 will not perform a planned third trimming of its trajectory along the earth-moon transfer orbit, according to the State Administration of Science, Technology and Industry for National Defense.
Chang'e-3, which is carrying moon rover "Yutu" (Jade Rabbit), was successfully launched early Monday morning from the Xichang Satellite Launch Center.
"The probe's carrier, an enhanced Long March-3B rocket, entered the orbit with comparatively high precision, and the first two orbital trimmings were highly exact, which resulted in the probe being capable of meeting the demands of near-moon deceleration and follow-up orbital control," said a statement released Thursday by the administration.
Noting good adaptability in the flying control plan for Chang'e-3, the statement added that "it has been decided that a third orbital trimming is not necessary."
If all goes well, the Chang'e-3 mission will mark the first time for China to send a spacecraft to soft-land on the surface of an extraterrestrial body, where it will conduct surveys of the Moon.
According to the administration, the variable thrust engine -- completely designed and made by Chinese scientists -- can realize continuous variation of thrust power ranging from 1,500 to 7,500 newtons. It will offer the main momentum for Chang'e-3 as it decelerates before reaching the lunar surface.
Chang'e-3 has been in normal operation for about 88 hours as of 6 p.m. Thursday, with a distance travelled of nearly 350,000 kilometers, according to the statement.
Quelle: Xinhua
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China's Chang'e-3 probe entered a circular lunar orbit at 5:53 p.m. Friday Beijing Time, after about 112 hours on a Earth-Moon transfer orbit, the Beijing Aerospace Control Center (BACC) said.
The probe entered the lunar orbit after 361 seconds of precise braking by the variable thrust engine, following orders by engineers with BACC.
The center later verified that Chang'e-3 had entered the 100 km-high lunar circular orbit.
The braking was important otherwise Chang'e-3 would have escapes from the Moon, or crashed into it, said BACC.
The probe was launched at 1:30 a.m. Monday from southwest China's Xichang Satellite Center. It should soft-land on the Moon in the middle of December.
Quelle: Xinhua
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Update: 7.12.2013
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BEIJING, China's Chang'e-3 probe entered a circular lunar orbit at 5:53 p.m. Friday Beijing Time, after about 112 hours on a Earth-Moon transfer orbit, the Beijing Aerospace Control Center (BACC) said.

The probe entered the lunar orbit after 361 seconds of precise braking by the variable thrust engine, following orders by engineers with BACC.

The center later verified that Chang'e-3 had entered the 100 km-high lunar circular orbit.

The braking was important otherwise Chang'e-3 would have escapes from the Moon, or crashed into it, said BACC.

The probe was launched at 1:30 a.m. Monday from southwest China's Xichang Satellite Center. It should soft-land on the Moon in the middle of December.

Quelle: Xinhua

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Update: 11.12.2013
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Chang'e-3 probe moves closer to the moon
               
BEIJING, China's lunar probe Chang'e-3 entered an orbit closer to the moon on Tuesday night.
Following an order from the Beijing Aerospace Control Center, the probe descended from the 100 km-high lunar circular orbit to an elliptical orbit with its nearest point about 15 km away from the moon's surface, the State Administration of Science, Technology and Industry for National Defense said in a statement.
The administration said the transition was conducted above the dark side of the moon at 9:20 p.m.
At 9:24 p.m., it was confirmed that Chang'e-3 had entered the new orbit.
In the new orbit, the probe will prepare for a soft-landing on the moon's surface, according to the statement.
Chang'e-3, which is carrying moon rover "Yutu" (Jade Rabbit), was successfully launched on Dec. 2 from the Xichang Satellite Launch Center.
It is expected to land on the moon in mid-December, and will be China's first spacecraft to soft-land on the surface of an extraterrestrial body.
Quelle: Xinhua  
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Update: 12.12.2013
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Chang'e-3 tritt in nähere Umlaufbahn von Mond
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The lunar probe Chang'e-3 moved a step closer to the moon on Tuesday night. The craft descended from a 100 kilometer-high lunar orbit to an elliptical orbit with its nearest point, just 15 kilometers from the moon’s surface.
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China's lunar probe Chang'e-3 entered an orbit closer to the moon on Dec. 10, 2013. 
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According to the State Administration of Science, Technology and Industry for National Defense, the transition took place above the dark side of the moon at 9.20 p.m, Beijing time. The transition took around four minutes. In the new orbit, Chang’e-3 will prepare for a soft-landing on the moon’s surface.
The probe, which is carrying the moon rover "Yutu", was launched on December the 2nd. China’s first soft-landing on the moon is set to take place in the coming days.
Quelle: Xinhua
 

 

 


Tags: Moon-Rover 14.December 2013 

3410 Views

Freitag, 13. Dezember 2013 - 12:56 Uhr

Raumfahrt - Vorbereitung für Progress M-22M Ankunft bei ISS im Februar 2014

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ISS orbit to be adjusted to ensure docking with Progress resupply spacecraft

The Station's forthcoming docking of Russian resupply spacecraft Progress M-22M is scheduled for February 5, 2014
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Russia's space flight control center (FCC) will adjust the orbit of the International Space Station (ISS) on Friday in order to ensure the Station's forthcoming docking of Russian resupply spacecraft Progress M-22M, the launch of which is slated for February 5, 2014, an FCC official told Itar-Tass.
"The engines of the cargo spacecraft Progress M-21M will be resorted to raise the ISS orbit. An ignition of the engines is scheduled for 18:57, Moscow time, on Friday, the FCC official said.
Within the 599-second operation of the propulsion plant, the ISS, upon getting an additional impulse of 1.3 m/sec, will rise by about 2 km. Thereby, the Station's average orbit altitude will be approximately 417 km.
ISS orbit adjustment maneuvers are usually carried out in order to bring the Station to a needed orbit for docking with a resupply spacecraft or a manned spaceship, and to create conditions for successful landings, as well as for evasion of space debris.
Every day, under the impact of terrestrial gravitational pull and other factors, the altitude of the ISS orbit lowers by 150-200 meters.
Quelle: Roscosmos

 


Tags: Progress M-22M 2014 

2658 Views

Freitag, 13. Dezember 2013 - 10:59 Uhr

Astronomie - Überraschungs Bild von WISE zum 4. Einsatzjahr

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March of Asteroids Across Dying Star

A dying star, called the Helix nebula, is shown surrounded by the tracks of asteroids in an image captured by NASA's Wide-field Infrared Survey Explorer, or WISE.

In this image, infrared wavelengths of light have been assigned different colors, with longer wavelengths being red, and shorter, blue. The bluish-green and red materials are expelled remnants of what was once a star similar to our sun. As the star aged, it puffed up and its outer layers sloughed off. The burnt-out core of the star, called a white dwarf, is heating the expelled material, inducing it to glow with infrared light. Over time, the brilliant object, known as a planetary nebula, will fade away, leaving just the white dwarf.

Skirting around the edges of the Helix nebula are the footprints of asteroids marching across the field of view. Each set of yellow dots is a series of pictures of an asteroid. As the asteroid moved, WISE snapped several pictures, all of which are represented in this view. Scientists use these data to discover and characterize asteroids, including those that pass relatively close to Earth, called near-Earth asteroids. Infrared data are particularly useful for finding the smaller, darker asteroids that are more difficult to see with visible light, and for measuring the asteroids' sizes.

The other streaks in the picture are Earth-orbiting satellites and cosmic rays.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages and operates the recently activated NEOWISE mission for NASA's Science Mission Directorate. The WISE mission was selected competitively under NASA's Explorers Program managed by the agency's Goddard Space Flight Center in Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory in Logan, Utah. The spacecraft was built by Ball Aerospace & Technologies Corp. in Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA.

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Quelle: NASA


2457 Views

Freitag, 13. Dezember 2013 - 10:40 Uhr

Luftfahrt - Galileo erzielt seine erste Flugrouten-Aufzeichnung

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ESA’s Galileo satellites have achieved their very first aerial fix of longitude, latitude and altitude, enabling the inflight tracking of a test aircraft.
ESA’s four Galileo satellites in orbit have supported months of positioning tests on the ground across Europe since the very first fix back in March.
Now the first aerial tracking using Galileo has taken place, marking the first time ever that Europe has been able to determine the position of an aircraft using only its own independent navigation system.
This milestone took place on a Fairchild Metro-II above Gilze-Rijen Air Force Base in the Netherlands at 12:38 GMT on 12 November.
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It came as part of an aerial campaign overseen jointly by ESA and the National Aerospace Laboratory of the Netherlands, NLR, with the support of Eurocontrol, the European Organisation for the Safety of Air Navigation, and LVNL, the Dutch Air Navigation Service Provider.  
A pair of Galileo test receivers was used aboard the aircraft, the same kind currently employed for Galileo testing in the field and in labs across Europe. They were connected to an aeronautical-certified triple-frequency Galileo-ready antenna mounted on top of the aircraft.
Tests were scheduled during periods when all four Galileo satellites were visible in the sky – four being the minimum needed for positioning fixes.
The receivers fixed the plane’s position and, as well as determining key variables such as the ‘position, velocity and timing’ accuracy, time to first fix, signal to noise ratio, range error and range–rate error.
Testing covered both Galileo’s publicly available Open Service and the more precise, encrypted Public Regulated Service, whose availability is limited to governmental entities.
Flights covered all major phases: take off, straight and level flight with constant speed, orbit, straight and level flight with alternating speeds, turns with a maximum bank angle of 60º, pull-ups and push-overs, approaches and landings.
They also allowed positioning to be carried out during a wide variety of conditions, such as vibrations, speeds up to 456 km/h, accelerations up to 2 ghorizontal and 0.5–1.5 gvertical, and rapid jerks. The maximum altitude reached during the flights were 3000 m.
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NLR’s Fairchild Metro-II is something of a satnav veteran, having previously performed initial European GPS testing back in the 1980s and the first tests of the European Geostationary Navigation Overlay Service, EGNOS, which sharpens GPS accuracy and monitors its reliability over Europe for high-accuracy or even ‘safety-of-life’ uses.
European partnership
The definition and development of Galileo’s in-orbit validation phase were carried out by ESA and co-funded by ESA and the EU.
The Full Operational Capability phase is managed and fully funded by the European Commission. The Commission and ESA have signed a delegation agreement by which ESA acts as design and procurement agent on behalf of the Commission.
Quelle: ESA

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Freitag, 13. Dezember 2013 - 10:24 Uhr

Mars-Chroniken - Erfolgreiche erste Alter-Bestimmung von Mars-Stein direkt auf dem Mars durchgeführt.

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First Rock Dating Experiment Performed on Mars

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Although researchers have determined the ages of rocks from other planetary bodies, the actual experiments—like analyzing meteorites and moon rocks—have always been done on Earth. Now, for the first time, researchers have successfully determined the age of a Martian rock—with experiments performed on Mars. The work, led by geochemist Ken Farley of the California Institute of Technology (Caltech), could not only help in understanding the geologic history of Mars but also aid in the search for evidence of ancient life on the planet.
Many of the experiments carried out by the Mars Science Laboratory (MSL) mission's Curiosity rover were painstakingly planned by NASA scientists more than a decade ago. However, shortly before the rover left Earth in 2011, NASA's participating scientist program asked researchers from all over the world to submit new ideas for experiments that could be performed with the MSL's already-designed instruments. Farley, W.M. Keck Foundation Professor of Geochemistry and one of the 29 selected participating scientists, submitted a proposal that outlined a set of techniques similar to those already used for dating rocks on Earth, to determine the age of rocks on Mars. Findings from the first such experiment on the Red Planet—published by Farley and coworkers this week in a collection of Curiosity papers in the journal Science Express—provide the first age determinations performed on another planet.
The paper is one of six appearing in the journal that reports results from the analysis of data and observations obtained during Curiosity's exploration at Yellowknife Bay—an expanse of bare bedrock in Gale Crater about 500 meters from the rover's landing site. The smooth floor of Yellowknife Bay is made up of a fine-grained sedimentary rock, or mudstone, that researchers think was deposited on the bed of an ancient Martian lake.
In March, Curiosity drilled holes into the mudstone and collected powdered rock samples from two locations about three meters apart. Once the rock samples were drilled, Curiosity's robotic arm delivered the rock powder to the Sample Analysis on Mars (SAM) instrument, where it was used for a variety of chemical analyses, including the geochronology—or rock dating—techniques.
One technique, potassium-argon dating, determines the age of a rock sample by measuring how much argon gas it contains. Over time, atoms of the radioactive form of potassium—an isotope called potassium-40—will decay within a rock to spontaneously form stable atoms of argon-40. This decay occurs at a known rate, so by determining the amount of argon-40 in a sample, researchers can calculate the sample's age.
Although the potassium-argon method has been used to date rocks on Earth for many decades, these types of measurements require sophisticated lab equipment that could not easily be transported and used on another planet. Farley had the idea of performing the experiment on Mars using the SAM instrument. There, the sample was heated to temperatures high enough that the gasses within the rock were released and could be analyzed by an onboard mass spectrometer.
Farley and his colleagues determined the age of the mudstone to be about 3.86 to 4.56 billion years old. "In one sense, this is an utterly unsurprising result—it's the number that everybody expected," Farley says.
Indeed, prior to Curiosity's geochronology experiment, researchers using the "crater counting" method had estimated the age of Gale Crater and its surroundings to be between 3.6 and 4.1 billion years old. Crater counting relies on the simple fact that planetary surfaces are repeatedly bombarded with objects that scar their surface with impact craters; a surface with many impact craters is presumed to be older than one with fewer craters. Although this method is simple, it has large uncertainties.
"What was surprising was that our result—from a technique that was implemented on Mars with little planning on Earth—got a number that is exactly what crater counting predicted," Farley says. "MSL instruments weren't designed for this purpose, and we weren't sure if the experiment was going to work, but the fact that our number is consistent with previous estimates suggests that the technique works, and it works quite well."
The researchers do, however, acknowledge that there is some uncertainty in their measurement. One reason is that mudstone is a sedimentary rock—formed in layers over a span of millions of years from material that eroded off of the crater walls—and thus the age of the sample drilled by Curiosity really represents the combined age of those bits and pieces. So while the mudstone indicates the existence of an ancient lake—and a habitable environment some time in the planet's distant past—neither crater counting nor potassium-argon dating can directly determine exactly when this was.
To provide an answer for how the geology of Yellowknife Bay has changed over time, Farley and his colleagues also designed an experiment using a method called surface exposure dating. "The surface of Mars, the surface of Earth, and basically all surfaces in the solar system are being bombarded by cosmic rays," explains Farley, and when these rays—very high-energy protons—blast into an atom, the atom's nucleus shatters, creating isotopes of other elements. Cosmic rays can only penetrate about two to three meters below the surface, so the abundance of cosmic-ray-debris isotopes in rock indicates how long that rock has been on the surface.
Using the SAM mass spectrometer to measure the abundance of three isotopes that result from cosmic-ray bombardment—helium-3, neon-21, and argon-36—Farley and his colleagues calculated that the mudstone at Yellowknife Bay has been exposed at the surface for about 80 million years. "All three of the isotopes give exactly the same answer; they all have their independent sources of uncertainty and complications, but they all give exactly the same answer. That is probably the most remarkable thing I've ever seen as a scientist, given the difficulty of the analyses," Farley says.
This also helps researchers looking for evidence of past life on Mars. Cosmic rays are known to degrade the organic molecules that may be telltale fossils of ancient life. However, because the rock at Yellowknife Bay has only been exposed to cosmic rays for 80 million years—a relatively small sliver of geologic time—"the potential for organic preservation at the site where we drilled is better than many people had guessed," Farley says.
Furthermore, the "young" surface exposure offers insight into the erosion history of the site. "When we first came up with this number, the geologists said, 'Yes, now we get it, now we understand why this rock surface is so clean and there is no sand or rubble,'" Farley says. 
The exposure of rock in Yellowknife Bay has been caused by wind erosion. Over time, as wind blows sand against the small cliffs, or scarps, that bound the Yellowknife outcrop, the scarps erode back, revealing new rock that previously was not exposed to cosmic rays.
"Imagine that you are in this site a hundred million years ago; the area that we drilled in was covered by at least a few meters of rock. At 80 million years ago, wind would have caused this scarp to migrate across the surface and the rock below the scarp would have gone from being buried—and safe from cosmic rays—to exposed," Farley explains. Geologists have developed a relatively well-understood model, called the scarp retreat model, to explain how this type of environment evolves. "That gives us some idea about why the environment looks like it does and it also gives us an idea of where to look for rocks that are even less exposed to cosmic rays," and thus are more likely to have preserved organic molecules, Farley says.
Curiosity is now long gone from Yellowknife Bay, off to new drilling sites on the route to Mount Sharp where more dating can be done. "Had we known about this before we left Yellowknife Bay, we might have done an experiment to test the prediction that cosmic-ray irradiation should be reduced as you go in the downwind direction, closer to the scarp, indicating a newer, more recently exposed rock, and increased irradiation when you go in the upwind direction, indicating a rock exposed to the surface longer ago," Farley says. "We'll likely drill in January, and the team is definitely focused on finding another scarp to test this on."
This information could also be important for Curiosity chief scientist John Grotzinger, Caltech's Fletcher Jones Professor of Geology. In another paper in the same issue of Science Express, Grotzinger—who studies the history of Mars as a habitable environment—and colleagues examined the physical characteristics of the rock layers in and near Yellowknife Bay. They concluded that the environment was habitable less than 4 billion years ago, which is a relatively late point in the planet's history.
"This habitable environment existed later than many people thought possible," Grotzinger says. His findings suggest that the surface water on Mars at that time would have been sufficient enough to make clays. Previously, such clays—evidence of a habitable environment—were thought to have washed in from older deposits. Knowing that the clays could be produced later in locations with surface water can help researchers pin down the best areas at which to look for once habitable environments, he says.
Farley's work is published in a paper titled "In-situ radiometric and exposure age dating of the Martian surface." Other Caltech coauthors on the study include Grotzinger, graduate student Hayden B. Miller, and Edward Stolper.
Quelle: caltech

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Freitag, 13. Dezember 2013 - 10:09 Uhr

Astronomie - Erste Edelgas-Moleküle im Weltraum

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Argon was forged in the doomed star that became the famous Crab Nebula: image taken by the Hubble Space Telescope. (Courtesy: NASA, ESA, J Hester and A Loll (Arizona State University))

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An international team of astronomers has accidentally spotted the first space molecules bearing a noble gas, argon. The surprising discovery, in the debris of an exploded star, reveals the element's isotopic composition, confirming long-standing predictions that argon is forged in such doomed stars.
Once called inert gases, the elements in the final column of the periodic table have closed outer shells of electrons that normally prevent them from exchanging electrons with other atoms to form molecules. In 1962, however, chemists discovered molecules containing xenon and now call these elements noble gases instead. But no-one had ever seen a molecule in space harbouring a noble gas, even though one such gas – helium – is the universe's second most abundant element.
Mike Barlow, an astronomer at University College London, and his colleagues were using the Herschel Space Observatory to study supernova remnants, including the well known Crab Nebula. It resulted when a massive star 6500 light-years from Earth in the constellation Taurus ran out of fuel, sparking a brilliant explosion that our ancestors witnessed in 1054.
Looking for common molecules
Barlow and his colleagues wanted to observe the Crab Nebula's dust, which radiates its heat at the far-infrared wavelengths that Herschel detects. They also searched the Herschel spectra for lines from common molecules such as carbon monoxide.
The scientists never found those molecules. Instead, they saw two mysterious emission lines – one at a wavelength of 243 microns, the other at 486 microns, exactly twice as long. "That was a giveaway that it was a simple diatomic molecule – two atoms rotating about each other," says Barlow. After failing to find a match with common diatomic molecules, the scientists realized that they had spotted the argon hydride molecular ion, the chemical formula of which is ArH+.
"It was very surprising to us," Barlow says. "Nobody had predicted the molecule. We call the discovery serendipitous to make it sound a bit more scientific, but it was an accident – a lucky discovery." The peculiar molecule probably forms when singly ionized argon – an argon atom with one of its electrons missing – meets molecular hydrogen (H2) and grabs a hydrogen atom.
Argon (atomic number 18) is the eleventh most abundant element in the universe and the third most common gas in the atmospheres of Venus, Earth and Mars. The element makes up 0.93% of the air that we breathe. Most terrestrial argon is argon-40, which comes from the decay of radioactive potassium-40 in rocks.
Lighter argon isotope
We call the discovery serendipitous to make it sound a bit more scientific, but it was an accident – a lucky discovery 
Mike Barlow, University College London
But theorists have long predicted that massive stars should manufacture large quantities of a lighter argon isotope, argon-36, which has equal numbers of protons and neutrons. Other astronomers had already detected argon atoms in the Crab Nebula. "But there was no direct proof that it was argon-36," Barlow says, because atomic spectral lines from different argon isotopes have nearly the same wavelengths, making it difficult to distinguish them.
For molecules, however, the task is easy, because molecules containing different argon isotopes emit radiation at noticeably different wavelengths. Therefore, the argon-hydride molecules revealed the element's isotopic composition: it is argon-36, just as the theory predicts.
Cherished beliefs borne out
"It's nice to see cherished beliefs borne out," says astronomer Stan Woosley, a supernova expert at the University of California at Santa Cruz, who was not involved with the discovery. Early in its life, a massive star shines by converting hydrogen into helium, as the Sun does. Then the star begins burning the helium into carbon and oxygen, which eventually forge still heavier elements. Argon arises during the oxygen-burning stage, in which one oxygen-16 nucleus hits another, creating sulphur-32. The sulphur nucleus is in an excited state and usually emits a helium-4 particle, thereby becoming silicon-28. The helium-4 particles strike the silicon-28 and sulphur-32 nuclei to make argon-36 and also calcium-40.
Woosley says that the timing of argon's creation depended on the star itself, which astronomers think was born eight to 16 times as massive as the Sun. If the lesser figure is correct, he says the element originated primarily in the supernova. If instead the star was born with the larger mass, it created most of its argon before the explosion, during the last few months of its life.
Massive stars should also produce smaller amounts of another argon isotope, argon-38. If scientists can detect it, they could compare its abundance with that of argon-36. "It's a direct test of nuclear reaction theory in supernovae," says Barlow. He hopes to use ground-based telescopes to search the Crab Nebula for the heavier argon isotope, because the Herschel Space Observatory recently ceased observations.
Barlow and his colleagues are publishing their discovery online today in Science.
Quelle: Physics World
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Astronomers discover first noble gas molecules in space

Noble gas molecules have been detected in space for the first time in the Crab Nebula, a supernova remnant, by astronomers at UCL.
Led by Professor Mike Barlow (UCL Department of Physics & Astronomy) the team used ESA's Herschel Space Observatory to observe the Crab Nebula in far infrared light.
Their measurements of regions of cold gas and dust led them to the serendipitous discovery of the chemical fingerprint of argon hydride ions, published today in the journal Science.
The findings support scientists' theories of how argon forms in nature.
The Herschel Space Observatory, an ESA space telescope which recently completed its mission, is the biggest space telescope ever to have flown.
Herschel's instruments were designed to detect far-infrared light, which has much longer wavelengths than we can see with our eyes.
"We were doing a survey of the dust in several bright supernova remnants using Herschel, one of which was the Crab Nebula. Discovering argon hydride ions here was unexpected because you don't expect an atom like argon, a noble gas, to form molecules, and you wouldn't expect to find them in the harsh environment of a supernova remnant," said Barlow.
Although hot objects like stars glow brightly in visible light, colder objects like the dust in nebulae radiate mainly in the infrared, wavelengths which are blocked by Earth's atmosphere.
Although nebulae can be seen in visible light, this light comes from hot excited gases within them; the cold and dusty component is invisible at optical wavelengths.
In addition to mapping the dust by making far-infrared images of the nebula, the team used Herschel's SPIRE instrument to make spectroscopic observations. In these, the infrared light is split up and dispersed according to its wavelength, much like a prism breaks white light down into its respective colours. When they looked at the data, the team saw some very unusual features which took some time to fully understand.
"Looking at infrared spectra is useful as it gives us the signatures of molecules, in particular their rotational signatures," Barlow said. "Where you have, for instance, two atoms joined together, they rotate around their shared centre of mass. The speed at which they can spin comes out at very specific, quantised, frequencies, which we can detect in the form of infrared light with our telescope."
Elements can exist in several different versions, or isotopes, which have different numbers of neutrons in their atomic nuclei. The properties of isotopes are very similar to one another in most respects, but they do differ slightly in mass. Because of this mass difference, the speed of rotation depends on which isotopes are present in a molecule.
The light coming from certain regions of the Crab Nebula showed extremely strong and unexplained peaks in intensity around 618 Gigahertz and 1235 GHz. Consulting databases of known properties of different molecules, the scientists found that the only possible explanation was that the emission was coming from spinning molecular ions of argon hydride. Moreover, the only isotope of argon whose hydride could rotate at that rate was argon-36.
In this case, energy from the neutron star at the heart of the nebula appears to have ionised the argon, which then joined with molecules of hydrogen to form the molecular ion ArH+.
Professor Bruce Swinyard (UCL Department of Physics & Astronomy and Rutherford Appleton Laboratory), a member of the team, added: "Our discovery was unexpected in another way – because normally when you find a new molecule in space, its signature is weak and you have to work hard to find it. In this case it just jumped out of our spectra."
The discovery of argon-36 in the Crab Nebula, as well as being the first detection of its kind, helps support scientists' theories of how argon forms in nature. Calculations of what elements are churned out by a supernova predict a lot of argon-36 and no argon-40 – exactly what the team observed in the Crab Nebula. On Earth, however, argon-40 is the dominant isotope as it is released by the radioactive decay of potassium in rocks.
This first discovery of an argon molecule in space continues a long tradition of noble gas research at UCL. Argon, along with the other noble gases, was discovered at UCL by William Ramsay at the end of the 19th century.
Quelle: EurekAlert
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This image shows a composite view of the Crab nebula, an iconic supernova remnant in our Milky Way galaxy, as viewed by the Herschel Space Observatory and the Hubble Space Telescope. Image credit: ESA/Herschel/PACS/MESS Key Programme Supernova Remnant Team; NASA, ESA and Allison Loll/Jeff Hester (Arizona State University)
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Crab Nebula, as Seen by Herschel and Hubble
This image shows a composite view of the Crab nebula, an iconic supernova remnant in our Milky Way galaxy, as viewed by the Herschel Space Observatory and the Hubble Space Telescope. Herschel is a European Space Agency (ESA) mission with important NASA contributions, and Hubble is a NASA mission with important ESA contributions.
A wispy and filamentary cloud of gas and dust, the Crab nebula is the remnant of a supernova explosion that was observed by Chinese astronomers in the year 1054.
The image combines Hubble's view of the nebula at visible wavelengths, obtained using three different filters sensitive to the emission from oxygen and sulphur ions and is shown here in blue. Herschel's far-infrared image reveals the emission from dust in the nebula and is shown here in red.
While studying the dust content of the Crab nebula with Herschel, a team of astronomers have detected emission lines from argon hydride, a molecular ion containing the noble gas argon. This is the first detection of a noble-gas based compound in space.
The Herschel image is based on data taken with the Photoconductor Array Camera and Spectrometer (PACS) instrument at a wavelength of 70 microns; the Hubble image is based on archival data from the Wide Field and Planetary Camera 2 (WFPC2).
Herschel is a European Space Agency cornerstone mission, with science instruments provided by consortia of European institutes and with important participation by NASA. NASA's Herschel Project Office is based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. JPL contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the United States astronomical community. Caltech manages JPL for NASA.
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Chemical Surprise Found in Crab Nebula

Astronomers have discovered a rare chemical pairing in the remains of an exploded star, called the Crab nebula. A gas thought to be a loner has made a "friend," linking up with a chemical partner to form a molecule. The discovery, made with the Herschel space observatory, a European Space Agency mission with important NASA contributions, will help scientists better understand supernovas, the violent deaths of massive stars. 
The unexpected find involves a noble gas called Argon, named for its chemical aloofness after the Greek word for "inactive." Noble gases, which also include helium and neon among others, rarely engage in chemical reactions. They prefer to go it alone. 
A new study, led by Michael Barlow from University College London, United Kingdom, and based on spectral data from Herschel, has found the first evidence of such a noble gas-based compound in space, a molecule called argon hydride. The results are published in the journal Science. 
"The strange thing is that it is the harsh conditions in a supernova remnant that seem to be responsible for some of the argon finding a partner with hydrogen," said Paul Goldsmith of NASA's Jet Propulsion Laboratory, Pasadena, Calif. 
"This is not only the first detection of a noble-gas based molecule in space, but also a new perspective on the Crab nebula. Herschel has directly measured the argon isotope we expect to be produced via explosive nucleosynthesis in a core-collapse supernova, refining our understanding of the origin of this supernova remnant," concludes Göran Pilbratt, Herschel project scientist at the European Space Agency. 
Quelle: NASA

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