samedi 22 mars 2014

Arianespace’s Ariane 5 orbits satellites at the service of SES and HISPASAT


















ARIANESPACE / ESA - Flight VA216 Mission poster.


March 22, 2014

Ariane Flight VA216


Images above: Ariane 5 performs another on-time lift-off from the Spaceport (photo at left) and ascends through a low cloud deck with its dual payload.

The workhorse Ariane 5 orbited a pair of payloads – ASTRA 5B for SES and HISPASAT’S Amazonas 4A – this evening, continuing the relationships with two customers that have come to rely on Arianespace’s launch services.

LIFTOFF of Ariane-V VA216 carrying Astra-5B and Amazonas-4A

Lifting off from the Spaceport in French Guiana, Flight VA216 provided a total payload lift performance of just under 9,580 kg. on the delivery mission to geostationary transfer orbit.  It was one of multiple launch campaigns currently underway for Arianespace missions, covering its full launcher family – composed of the heavy-lift Ariane 5, medium-lift Soyuz and light-lift Vega.

video
VA216 - Mission Accomplished!

ASTRA 5B was deployed by Ariane 5 at 27 minutes into the mission, with Amazonas 4A separated from the launcher at 34 minutes after liftoff.

This was Ariane 5’s second flight in 2014, and the 73rd overall launch of the vehicle – continuing its on-target track record with the 59th consecutive success.  The mission was designated Flight VA216 in Arianespace’s launcher family numbering system.

ASTRA 5B was produced by Airbus Defence and Space using a Eurostar 3000 L platform, and had a mass at liftoff of approximately 5,755 kg.  It is fitted with 40 active Ku-band and 6 Ka-band transponders, and will be positioned at 31.5 degrees East.

 ASTRA 5B satellite

Amazonas 4A was the eighth satellite launched by Arianespace for Spain, and is part of the Amazonas relay platform series that is expanding HISPASAT’s business over South America.

Amazonas 4A satellite

As the 25th Orbital Sciences Corporation-built satellite launched by Arianespace, Amazonas 4A is based on a GEOStar-2.4 platform, and weighed in at about 3,000 kg. for liftoff.  This high-power satellite’s 24 active Ku-band transponders will provide a broad range of telecommunications services across all of South America, and has a design life of 15 years.

In addition to tonight’s Ariane 5 success, parallel preparations are underway at the Spaceport for Arianespace’s next mission – Soyuz Flight VS07, scheduled for liftoff on April 3 with Europe’s Sentinel-1A; and Vega Flight VV03 with the European-built DZZ-HR multi-mission satellite for Kazakhstan.  The European Space Agency’s Automated Transfer Vehicle (ATV) Georges Lemaître is at the Spaceport undergoing checkout in advance of an Ariane 5 mission in July for servicing of the International Space Station.

Related links:

Airbus Defence and Space website: http://www.astrium.eads.net/

SES website: http://www.ses.com/

HISPASAT website: http://www.hispasat.com/

Orbital Sciences Corporation website: http://www.orbital.com/

Images, Video, Text, Credits: Arianespace / Arianespace TV / Astrium / Gunter's Space Page / Screen captures: Orbiter.ch Aerospace.

Greetings, Orbiter.ch

vendredi 21 mars 2014

Cool running for CMS tracker












CERN - European Organization for Nuclear Research logo.

March 21, 2014

By successfully passing a recent ‘Master Cold Test’, the CMS experiment Tracker has proved it can run at temperatures colder than ever before. It is now in shape to operate until 2025.

This Tracker – the closest subdetector to the collision point of Large Hadron Collider (LHC) particle beams – must face an onslaught of billions of particles flying through it each second of operation. If the Tracker was operated at room temperatures, damage from this onslaught would soon render it inoperable. So during the LHC’s first run from 2010 to 2013, the Tracker operated at +4 °C. But with higher LHC beam intensities from 2015 onwards, the Tracker must operate at much colder temperatures, posing a monumental challenge to the Tracker community. However, after two years of planning and one year of work, they have succeeded.


Image above: The CMS Tracker Outer Barrel (TOB) shown in a clean room before its installation into the detector in 2008 (Image: Maximilien Brice/CERN).

To achieve lower temperatures, many projects ran in parallel. The CMS cooling plant was refurbished and the fluorocarbon cooling system completely overhauled. New methods for vapour-sealing and insulation helped suppress humidity inside the Tracker and several hundred high-precision sensors have improved humidity and temperature monitoring. A new dry-gas plant now provides eight times as much dry gas (air or nitrogen) than before to help keep humidity away from the delicate electronics, and allows fine-grained regulation of the flow. In addition, all cooling bundles outside the Tracker were equipped with heater wires and temperature sensors to guarantee safe operation in the future.

As a result, in early 2014 the Tracker successfully passed the important ‘Master Cold Test’ milestone, running the Strip Tracker at temperatures down to −20°C with the Pixel Tracker lines going to −25°C. The subdetector was monitored continuously and performed as expected, without affecting the temperature of surrounding layers of the Electromagnetic Calorimeter, which operate at +18°C.
Environmental conditions allow operation at −25°C and the detector has been successfully operated at −20°C. To minimise thermal stress, researchers are discussing operating the Strip Tracker at −15°C and the Pixel Tracker at −20°C for the coming years.

With this milestone, the Tracker project has completed the bulk of its work for Long Shutdown 1 of the LHC. The detector can now be operated cold with a sufficient safety margin. The team are now ready to track particles until Long Shutdown 3!

More images of the CMS tracker can be found on the CERN Document Server: https://cds.cern.ch/record/1431469

Note:

CERN, the European Organization for Nuclear Research, is the world's leading laboratory for particle physics. It has its headquarters in Geneva. At present, its Member States are Austria, Belgium, Bulgaria, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Italy, the Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom. Romania is a candidate for accession. Israel is an Associate Member in the pre-stage to Membership. India, Japan, the Russian Federation, the United States of America, Turkey, the European Commission and UNESCO have Observer status.

Related links:

Large Hadron Collider (LHC): http://home.web.cern.ch/topics/large-hadron-collider

CMS experiment: http://home.web.cern.ch/about/experiments/cms

For more information about the European Organization for Nuclear Research (CERN), visit: http://home.web.cern.ch/

Image, Text, Credits: CERN / Nicola Bacchetta, Erik Butz, Francesco Palmonari, Antti Onnela and Frank Hartmann.

Greetings, Orbiter.ch

LHC and Tevatron scientists announce first joint result












CERN - European Organization for Nuclear Research logo.

March 21, 2014

Scientists working on experiments at CERN’s Large Hadron Collider (LHC) and Fermilab’s Tevatron colliders have joined forces to produce a more precise measurement of the mass of the top quark.

Scientists from the four experiments involved—ATLAS, CDF, CMS and DZero—announced their joint findings at the Rencontres de Moriond international physics conference in Italy.

The four experiments pooled their data analysis power to arrive at a new world’s best value for the mass of the top quark of 173.34 plus/minus 0.76 GeV/c2.


Graphic above: This graphic shows the four individual top quark mass measurements published by the ATLAS, CDF, CMS and DZero collaborations, together with the most precise measurement obtained in a joint analysis.

Experiments at the LHC at the CERN laboratory in Geneva, Switzerland and the Tevatron collider at Fermilab near Chicago in Illinois, USA are the only ones that have ever seen top quarks—the heaviest elementary particles ever observed.  The top quark’s huge mass (more than 100 times that of the proton) makes it one of the most important tools in the physicists’ quest to understand the nature of the universe.

The new precise value of the top-quark mass will allow scientists to test further the mathematical framework that describes the quantum connections between the top quark, the Higgs particle and the carrier of the electroweak force, the W boson. Theorists will explore how the new, more precise value will change predictions regarding the stability of the Higgs field and its effects on the evolution of the universe. It will also allow scientists to look for inconsistencies in the Standard Model of particle physics – searching for hints of new physics that will lead to a better understanding of the nature of the universe.

For more information read the press release: http://press.web.cern.ch/press-releases/2014/03/international-team-lhc-and-tevatron-scientists-announces-first-joint-result

Note:

CERN, the European Organization for Nuclear Research, is the world's leading laboratory for particle physics. It has its headquarters in Geneva. At present, its Member States are Austria, Belgium, Bulgaria, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Italy, the Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom. Romania is a candidate for accession. Israel is an Associate Member in the pre-stage to Membership. India, Japan, the Russian Federation, the United States of America, Turkey, the European Commission and UNESCO have Observer status.

Related links:

Large Hadron Collider (LHC): http://home.web.cern.ch/topics/large-hadron-collider

Fermilab: http://www.fnal.gov/

ATLAS experiment: http://home.web.cern.ch/about/experiments/atlas

CMS experiment: http://home.web.cern.ch/about/experiments/cms

Higgs particle: http://home.web.cern.ch/topics/higgs-boson

Standard Model of particle physics: http://home.web.cern.ch/about/physics/standard-model

CDF experiment: http://www-cdf.fnal.gov/index.html

DZero experiment: http://www-d0.fnal.gov/

Rencontres de Moriond: http://moriond.in2p3.fr/

Graphic, Text, Credit: CERN.

Best regards, Orbiter.ch

Hubble Peers at the Heart of NGC 5793











NASA - Hubble Space Telescope patch.

March 21, 2014

 Hubble Peers at the Heart of NGC 5793

This new Hubble image is centered on NGC 5793, a spiral galaxy over 150 million light-years away in the constellation of Libra. This galaxy has two particularly striking features: a beautiful dust lane and an intensely bright center — much brighter than that of our own galaxy, or indeed those of most spiral galaxies we observe.

NGC 5793 is a Seyfert galaxy. These galaxies have incredibly luminous centers that are thought to be caused by hungry supermassive black holes — black holes that can be billions of times the size of the sun — that pull in and devour gas and dust from their surroundings.

This galaxy is of great interest to astronomers for many reasons. For one, it appears to house objects known as masers. Whereas lasers emit visible light, masers emit microwave radiation. The term "masers" comes from the acronym Microwave Amplification by Stimulated Emission of Radiation. Maser emission is caused by particles that absorb energy from their surroundings and then re-emit this in the microwave part of the spectrum.

Naturally occurring masers, like those observed in NGC 5793, can tell us a lot about their environment; we see these kinds of masers in areas where stars are forming. In NGC 5793 there are also intense mega-masers, which are thousands of times more luminous than the sun.

For more information about Hubble Space Telescope, visit: http://www.spacetelescope.org/ and http://hubblesite.org/

Image, Text, Credits:  NASA, ESA, and E. Perlman (Florida Institute of Technology).

Cheers, Orbiter.ch

jeudi 20 mars 2014

Hardy Star Survives Supernova Blast











NASA - Chandra X-ray Observatory patch.

March 20, 2014


When a massive star runs out fuel, it collapses and explodes as a supernova.  Although these explosions are extremely powerful, it is possible for a companion star to endure the blast. A team of astronomers using NASA’s Chandra X-ray Observatory and other telescopes has found evidence for one of these survivors.

This hardy star is in a stellar explosion’s debris field − also called its supernova remnant − located in an HII region called DEM L241. An HII (pronounced "H-two") region is created when the radiation from hot, young stars strips away the electrons from neutral hydrogen atoms (HI) to form clouds of ionized hydrogen (HII). This HII region is located in the Large Magellanic Cloud, a small companion galaxy to the Milky Way.

A new composite image of DEM L241 contains Chandra data (purple) that outlines the supernova remnant. The remnant remains hot and therefore X-ray bright for thousands of years after the original explosion occurred. Also included in this image are optical data from the Magellanic Cloud Emission Line Survey (MCELS) taken from ground-based telescopes in Chile (yellow and cyan), which trace the HII emission produced by DEM L241. Additional optical data from the Digitized Sky Survey (white) are also included, showing stars in the field.

R. Davies, K. Elliott, and J. Meaburn, whose last initials were combined to give the object the first half of its name, first mapped DEM L241 in 1976. The recent data from Chandra revealed the presence of a point-like X-ray source at the same location as a young massive star within DEM L241’s supernova remnant.

Astronomers can look at the details of the Chandra data to glean important clues about the nature of X-ray sources.  For example, how bright the X-rays are, how they change over time, and how they are distributed across the range of energy that Chandra observes.

In this case, the data suggest that the point-like source is one component of a binary star system.  In such a celestial pair, either a neutron star or black hole (formed when the star went supernova) is in orbit with a star much larger than our Sun. As they orbit one another, the dense neutron star or black hole pulls material away its companion star through the wind of particles that flows away from its surface. If this result is confirmed, DEM L241 would be only the third binary containing both a massive star and a neutron star or black hole ever found in the aftermath of a supernova.

Chandra X-ray Observatory

Chandra’s X-ray data also show that the inside of the supernova remnant is enriched in oxygen, neon and magnesium. This enrichment and the presence of the massive star imply that the star that exploded had a mass greater than 25 times, to perhaps up to 40 times, that of the Sun.

Optical observations with the South African Astronomical Observatory's 1.9-meter telescope show the velocity of the massive star is changing and that it orbits around the neutron star or black hole with a period of tens of days. A detailed measurement of the velocity variation of the massive companion star should provide a definitive test of whether or not the binary contains a black hole.

Indirect evidence already exists that other supernova remnants were formed by the collapse of a star to form a black hole. However, if the collapsed star in DEM L241 turns out to be a black hole, it would provide the strongest evidence yet for such a catastrophic event.

What does the future hold for this system? If the latest thinking is correct, the surviving massive star will be destroyed in a supernova explosion some millions of years from now. When it does, it may form a binary system containing two neutron stars or a neutron star and a black hole, or even a system with two black holes.

A paper describing these results is available online and was published in the November 10, 2012 issue of The Astrophysical Journal (http://arxiv.org/abs/1208.1453). The authors are Fred Seward of the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA; P. Charles from University of Southampton, UK; D. Foster from the South African Astronomical Observatory in Cape Town, South Africa; J. Dickel and P. Romero from University of New Mexico in Albuquerque, NM; Z. Edwards, M. Perry and R. Williams from Columbus State University in Columbus, GA.

NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Mass., controls Chandra's science and flight operations.

View large image: http://chandra.harvard.edu/photo/2014/deml241/

Chandra on Flickr: http://www.flickr.com/photos/nasamarshall/sets/72157606205297786/

Images, Text, Credits: X-ray: NASA/CXC/SAO/F. Seward et al; Optical: NOAO/CTIO/MCELS, DSS.

Cheers, Orbiter.ch

NASA's Spitzer Telescope Brings 360-Degree View of Galaxy to Our Fingertips












NASA - Spitzer Space Telescope patch.

March 20, 2014

Touring the Milky Way now is as easy as clicking a button with NASA's new zoomable, 360-degree mosaic presented Thursday at the TEDActive 2014 Conference in Vancouver, Canada.

The star-studded panorama of our galaxy is constructed from more than 2 million infrared snapshots taken over the past 10 years by NASA's Spitzer Space Telescope.


Image above: A new panorama from NASA's Spitzer Space Telescope shows us our galaxy's plane all the way around us in infrared light. Image Credit: NASA/JPL-Caltech/University of Wisconsin.

"If we actually printed this out, we'd need a billboard as big as the Rose Bowl Stadium to display it," said Robert Hurt, an imaging specialist at NASA's Spitzer Space Science Center in Pasadena, Calif. "Instead we’ve created a digital viewer that anyone, even astronomers, can use."

The 20-gigapixel mosaic uses Microsoft’s WorldWide Telescope visualization platform. It captures about three percent of our sky, but because it focuses on a band around Earth where the plane of the Milky Way lies, it shows more than half of all the galaxy's stars.

The image, derived primarily from the Galactic Legacy Mid-Plane Survey Extraordinaire project, or GLIMPSE360, is online at:

http://www.spitzer.caltech.edu/glimpse360

Spitzer, launched into space in 2003, has spent more than 10 years studying everything from asteroids in our solar system to the most remote galaxies at the edge of the observable universe. In this time, it has spent a total of 4,142 hours (172 days) taking pictures of the disk, or plane, of our Milky Way galaxy in infrared light. This is the first time those images have been stitched together into a single expansive view.

Our galaxy is a flat spiral disk; our solar system sits in the outer one-third of the Milky Way, in one of its spiral arms. When we look toward the center of our galaxy, we see a crowded, dusty region jam-packed with stars. Visible-light telescopes cannot look as far into this region because the amount of dust increases with distance, blocking visible starlight. Infrared light, however, travels through the dust and allows Spitzer to view past the galaxy's center.

Spitzer Space Telescope. Image Credit: NASA/JPL-Caltech

"Spitzer is helping us determine where the edge of the galaxy lies," said Ed Churchwell, co-leader of the GLIMPSE team at the University of Wisconsin-Madison. "We are mapping the placement of the spiral arms and tracing the shape of the galaxy."

Using GLIMPSE data, astronomers have created the most accurate map of the large central bar of stars that marks the center of the galaxy, revealing the bar to be slightly larger than previously thought. GLIMPSE images have also shown a galaxy riddled with bubbles. These bubble structures are cavities around massive stars, which blast wind and radiation into their surroundings.

All together, the data allow scientists to build a more global model of stars, and star formation in the galaxy -- what some call the "pulse" of the Milky Way. Spitzer can see faint stars in the "backcountry" of our galaxy -- the outer, darker regions that went largely unexplored before.

"There are a whole lot more lower-mass stars seen now with Spitzer on a large scale, allowing for a grand study," said Barbara Whitney of the University of Wisconsin, Madison, co-leader of the GLIMPSE team. "Spitzer is sensitive enough to pick these up and light up the entire 'countryside' with star formation."

The Spitzer team previously released an image compilation showing 130 degrees of our galaxy, focused on its hub. The new 360-degree view will guide NASA's upcoming James Webb Space Telescope to the most interesting sites of star-formation, where it will make even more detailed infrared observations.

Some sections of the GLIMPSE mosaic include longer-wavelength data from NASA's Wide-field Infrared Survey Explorer, or WISE, which scanned the whole sky in infrared light.

The GLIMPSE data are also part of a citizen science project, where users can help catalog bubbles and other objects in our Milky Way galaxy. To participate, visit: http://www.milkywayproject.org

More information about Spitzer is online at: http://www.nasa.gov/spitzer

Images (mentioned), Text, Credits: NASA / J.D. Harrington / JPL / Whitney Clavin.

Greetings, Orbiter.ch

mercredi 19 mars 2014

NASA Orbiter Finds New Gully Channel on Mars












NASA - Mars Reconnaissance Orbiter (MRO) patch.

March 19, 2014

Before and After Images: 

Before
 
After

Images above: This pair of before and after images from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter documents formation of a new channel on a Martian slope between 2010 and 2013, likely resulting from activity of carbon-dioxide frost. Image Credit: NASA/JPL-Caltech/Univ. of Arizona.

A comparison of images taken by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter in November 2010 and May 2013 reveal the formation of a new gully channel on a crater-wall slope in the southern highlands of Mars.

These before-and-after images are available online at http://www.nasa.gov/jpl/new-gully-channel-terra-sirenum-pia17958 .

Gully or ravine landforms are common on Mars, particularly in the southern highlands. This pair of images shows that material flowing down from an alcove at the head of a gully broke out of an older route and eroded a new channel. The dates of the images are more than a full Martian year apart, so the observations did not pin down the Martian season of the activity at this site. Before-and-after HiRISE pairs of similar activity at other sites demonstrate that this type of activity generally occurs in winter, at temperatures so cold that carbon dioxide, rather than water, is likely to play the key role.

Artist's view of the Mars Reconnaissance Orbiter (MRO). Image Credit: NASA/JPL-Caltech

HiRISE is operated by the University of Arizona, Tucson. The instrument was built by Ball Aerospace & Technologies Corp., Boulder, Colo. The Mars Reconnaissance Orbiter Project is managed for NASA's Science Mission Directorate, Washington, by NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena.

For more information about HiRISE, see http://hirise.lpl.arizona.edu .  For more information about the Mars Reconnaissance Orbiter, visit http://www.nasa.gov/mro  

Image (mentioned), Text, Credits: NASA / JPL / Guy Webster.

Greetings, Orbiter.ch

mardi 18 mars 2014

NASA Releases First Interactive Mosaic of Lunar North Pole












NASA - Lunar Reconnaissance Orbiter (LRO) patch.

March 18, 2014

Scientists, using cameras aboard NASA's Lunar Reconnaissance Orbiter (LRO), have created the largest high resolution mosaic of our moon’s north polar region. The six-and-a-half feet (two-meters)-per-pixel images cover an area equal to more than one-quarter of the United States.

Web viewers can zoom in and out, and pan around an area. Constructed from 10,581 pictures, the mosaic provides enough detail to see textures and subtle shading of the lunar terrain. Consistent lighting throughout the images makes it easy to compare different regions.

"This unique image is a tremendous resource for scientists and the public alike," said John Keller, LRO project scientist at NASA's Goddard Space Flight Center, Greenbelt, Md. "It's the latest example of the exciting insights and data products LRO has been providing for nearly five years."

The images making up the mosaic were taken by the two LRO Narrow Angle Cameras, which are part of the instrument suite known as the Lunar Reconnaissance Orbiter Camera (LROC). The cameras can record a tremendous dynamic range of lit and shadowed areas.


Image above: A new interactive mosaic from NASA's Lunar Reconnaissance Orbiter covers the north pole of the moon from 60 to 90 degrees north latitude at a resolution of 6-1/2 feet (2 meters) per pixel. Close-ups of Thales crater (right side) zoom in to reveal increasing levels of detail. Image Credit: NASA/GSFC/Arizona State University.

"Creation of this giant mosaic took four years and a huge team effort across the LRO project," said Mark Robinson, principal investigator for the LROC at Arizona State University in Tempe. "We now have a nearly uniform map to unravel key science questions and find the best landing spots for future exploration."

The entire image measures 931,070 pixels square – nearly 867 billion pixels total. A complete printout at 300 dots per inch – considered crisp resolution for printed publications – would require a square sheet of paper wider than a professional U.S. football field and almost as long. If the complete mosaic were processed as a single file, it would require approximately 3.3 terabytes of storage space. Instead, the processed mosaic was divided into millions of small, compressed files, making it manageable for users to view and navigate around the image using a web browser.

LRO entered lunar orbit in June 2009 equipped with seven instrument suites to map the surface, probe the radiation environment, investigate water and key mineral resources, and gather geological clues about the moon's evolution.

Researchers used additional information about the moon's topography from LRO's Lunar Orbiter Laser Altimeter, as well as gravity information from NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission, to assemble the mosaic. Launched in September 2011, the GRAIL mission, employing twin spacecraft named Ebb and Flow, generated a gravity field map of the moon -- the highest resolution gravity field map of any celestial body.

LRO is managed by Goddard for the Science Mission Directorate (SMD) at NASA Headquarters in Washington. LROC was designed and built by Malin Space Science Systems and is operated by the University of Arizona. NASA's Jet Propulsion Laboratory in Pasadena, Calif., managed the GRAIL mission for SMD.

For more information about LRO, visit: http://www.nasa.gov/lro

To access the complete collection of LROC images, visit: http://lroc.sese.asu.edu/

To view the image with zoom and pan capability, visit: http://lroc.sese.asu.edu/gigapan

Image (mentioned), Text, Credit: NASA.

Cheers, Orbiter.ch

NASA's STEREO Studies Extreme Space Weather












NASA - STEREO Mission logo.

March 18, 2014

video
STEREO Captures Fastest CME to Date

Video above: Scientists studied this unusually fast coronal mass ejection – shown here in a movie from NASA's STEREO-A from July 22, 2012, at 10:00 p.m. EDT until 2 a.m. on July 23 – to improve models of extreme space weather. Because the CME headed toward STEREO-A, it appears like a giant halo around the sun. Image Credit: NASA/STEREO/Helioviewer.

On July 22, 2012, a massive cloud of solar material erupted off the sun's right side, zooming out into space and passing one of NASA's twin Solar Terrestrial Relations Observatory, or STEREO, spacecraft along the way. Scientists clocked this giant cloud, known as a coronal mass ejection, or CME, as traveling over 1,800 miles per second as it left the sun.

Conversations began to buzz and the emails to fly: this was the fastest CME ever observed by STEREO, which since its launch in 2006 has helped make CME speed measurements much more precise. Measuring a CME at this speed, traveling in a direction safely away from Earth, represented a fantastic opportunity for researchers studying the sun's effects. Now, a paper in Nature Communications, published on March 18, 2014, describes how a combination of events worked together to create these incredible speeds.

"The authors believe this extreme event was due to the interaction of two CMEs separated by only 10 to 15 minutes," said Joe Gurman, project scientist for STEREO at NASA's Goddard Space Flight Center in Greenbelt, Md. "Plus the CMEs traveled through a region of space that had been cleared out by another CME four days earlier."

The researchers describe the July 2012 event as a perfect storm, referring to the phrase originally coined for the October 1991 Atlantic Ocean storm to describe an event where a rare combination of circumstances can drastically aggravate a situation.


Image above: This image captured on July 23, 2012, at 12:24 a.m. EDT, shows a coronal mass ejection that left the sun at the unusually fast speeds of over 1,800 miles per second. Image Credit: NASA/STEREO.

Such work helps scientists understand how extreme solar events form and what their effects might be if aimed toward Earth. At Earth, the harshest space weather can have strong effects on the magnetic system surrounding the planet, which in turn can affect satellites and interrupt GPS and radio communications. At its worst, rapidly changing magnetic field lines around Earth can induce electric surges in the power utility grids on the ground. One of the best ways to protect against such problems, and perhaps learn to predict the onset of one of these storms, is to make computer models matching the observations of past events.

In the case of the July 2012 event, three spacecraft offered data on the CMEs: the two STEREO spacecraft and the joint European Space Agency/NASA Solar and Heliospheric Observatory, or SOHO. SOHO lies between Earth and the sun, while the two STEREO spacecraft have orbits that for most of their journey give views of the sun that cannot be had from Earth. Each spacecraft observed the CMEs from a different angle, and together they could help map out a three-dimensional image of what happened.

NASA's STEREO-A spacecraft. Image Credit: NASA

The authors suggest it was the successive, one-two punch of the CMEs that was the key to the high speeds of the event – speeds that would lead to circling Earth five times in one minute.  A CME from four days earlier had an impact too. First, it swept aside particles in the way, making it all the easier for the next CMEs to travel.  Second, it altered the normal spiral of the magnetic fields around the sun to a straighter pattern above the region that was the source for these CMEs, thus allowing for freer movement.

"A key finding is that it’s not just the initial conditions on the sun that can produce an extreme space weather storm," said Gurman. "The interactions between successive coronal mass ejections farther out in interplanetary space need to be considered as well."

The researchers found that state-of-the-art models that didn't take the effects of successive CMEs into consideration failed to correctly simulate the July 2012 event.  Such information will be incorporated into the models being tested by space weather forecasters. This should lead to better predictions of the worst storms and better protection of Earth and our technology in space.

Related Links:

NASA's STEREO mission: http://www.nasa.gov/stereo

SOHO mission site: http://sohowww.nascom.nasa.gov/

July 2012 solar event: http://www.nasa.gov/mission_pages/stereo/news/fast-cme.html

Images (mentioned), Video (mentioned), Text, Credits: NASA's Goddard Space Flight Center / Karen C. Fox.

Greetings, Orbiter.ch

Herschel Completes largest survey of cosmic dust in local universe












ESA - Herschel Mission patch.

18 March 2014

Herschel survey in infrared and visible

The largest census of dust in local galaxies has been completed using data from ESA’s Herschel space observatory, providing a huge legacy to the scientific community.

Cosmic dust grains are a minor but fundamental ingredient in the recipe of gas and dust for creating stars and planets. But despite its importance, there is an incomplete picture of the dust properties in galaxies beyond our own Milky Way.

Key questions include how the dust varies with the type of galaxy, and how it might affect our understanding of how galaxies evolve.

Herschel survey in infrared

Before concluding its observations in April 2013, Herschel provided the largest survey of cosmic dust, spanning a wide range of nearby galaxies located 50–80 million light-years from Earth.

The catalogue contains 323 galaxies with varying star formation activity and different chemical compositions, observed by Herschel’s instruments across far-infrared and submillimetre wavelengths.

A sample of these galaxies is displayed in a collage, arranged from dust-rich in the top left to dust-poor in the bottom right.

The dust-rich galaxies are typically spiral or irregular, whereas the dust-poor ones are usually elliptical. Blue and red colours represent cooler and warmer regions of dust, respectively.

Herschel survey in visible light

Dust is gently heated across a range of temperatures by the combined light of all of the stars in each galaxy, with the warmest dust being concentrated in regions where stars are being born.

For comparison, the galaxies are also shown in visible light images obtained by the Sloan Digital Sky Survey. Here, blue corresponds to young stars – hot, massive stars that burn through their fuel very quickly and are therefore short-lived.

Conversely, red stars are older population – they are less massive and cooler, and therefore live for longer.

The Herschel observations allow astronomers to determine how much light is emitted by the dust as a function of wavelength, providing a means to study the physical properties of the dust.

For example, a galaxy forming stars at a faster rate should have more massive, hot stars in it, and thus the dust in the galaxy should also be warmer. In turn, that means that more of the light emitted by the dust should come out at shorter wavelengths.

ESA’s Herschel space observatory (mission ended, out of service)

However, the data show greater variations than expected from one galaxy to another based on their star formation rates alone, implying that other properties, such as its chemical enrichment, also play an important role.

By allowing astronomers to investigate these correlations and dependences, the survey provides a much-needed local benchmark for quantifying the role played by dust in galaxy evolution throughout the history of the Universe.

The data will complement observations being made by other telescopes, such as the ground-based Atacama Large Millimeter Array in Chile, which will allow astronomers to look at dust in galaxies to the very edge of the observable Universe.

More information:

“PACS photometry of the Herschel Reference Survey – far-infrared/sub-millimeter colours as tracers of dust properties in nearby galaxies,” by L. Cortese et al., is published in the Monthly Notices of the Royal Astronomical Society, 18 March 2014.

For more information about Herschel mission, visit: http://www.esa.int/Our_Activities/Space_Science/Herschel

Images, Text, Credits: ESA/Herschel/HRS-SAG2 and HeViCS Key Programmes/Sloan Digital Sky Survey/ L. Cortese (Swinburne University).

Best regards, Orbiter.ch

lundi 17 mars 2014

Hubble revisits the Monkey Head Nebula for 24th birthday snap












ESA - Hubble Space Telescope logo.

17 March 2014

New Hubble image of NGC 2174

To celebrate its 24th year in orbit, the NASA/ESA Hubble Space Telescope has released a beautiful new image of part of NGC 2174, also known as the Monkey Head Nebula. This colourful region is filled with young stars embedded within bright wisps of cosmic gas and dust.

NGC 2174 lies about 6400 light-years away in the constellation of Orion (The Hunter). Hubble previously viewed this part of the sky back in 2001, creating a stunning image released in 2011, and the space telescope has now revisited the region to celebrate its 24th year of operation.

Wide field image of NGC 2174 (ground-based view)

Nebulae are a favourite target for Hubble. Their colourful plumes of gas and fiery bright stars create ethereally beautiful pictures. Some of the most famous of Hubble's images have been of nebulae — for example, the telescope's 22nd and 23rd anniversary images of the Tarantula (heic1206) and Horsehead (heic1307) nebulae, and its festive 2012 image of planetary nebula NGC 5189 (heic1220).

The detail shown in this image lies within NGC 2174, a nebula which gets its more common name, the Monkey Head Nebula, from its curiously familiar shape when viewed in wide-field images.

Visible and Infrared Comparison of NGC 2174

The nebula is a violent stellar nursery, packed with the ingredients needed for star formation. However, the recipe for cooking up new stars isn't very efficient and most of the ingredients are wasted as the cloud of gas and dust disperses. This process is accelerated by the presence of fiercely hot young stars which trigger high velocity winds that help to blow the gas outwards.

A vibrant palette of colours can be seen in this new image of NGC 2174. Dark brown and rust-coloured dust clouds billow outwards, framed against a background of bright blue gas. These striking hues are formed by combining several Hubble images taken with different coloured filters, to reveal a broad range of colours not normally visible to the human eye.

Location of the Hubble IR Detail in NGC 2174

The icing on this cosmic birthday cake takes the form of young white and pink stars sprinkled amongst the glowing clouds, pushing away the dark stellar nurseries in which they formed. The key ingredient in NGC 2174 is hydrogen gas, which is ionised by the ultraviolet radiation emitted by the young stars. As a result, this region is also known as an HII region [1] — a large cloud of ionised gas.

video
Zooming in on NGC 2174

This image marks 24 years of Hubble. This milestone will be further celebrated by a conference being held in Rome, Italy, in March of this year. The conference, entitled Science with the Hubble Space Telescope IV, will highlight and celebrate the scientific breakthroughs that Hubble has made over the last two decades and look into the future at the topics and key questions that will shape the field of astrophysics in the next decade.

video
Panning across NGC 2174

This portion of the Monkey Head Nebula was imaged in the infrared using Hubble's Wide Field Camera 3. Hubble's earlier Wide Field Planetary Camera 2 image from 2011 inspired its choice as the telescope's 24th anniversary image. A processed version of the WFPC2 dataset was entered into the Hubble's Hidden Treasures image processing competition by Yurij Tukachev.

video
Hubble orbiting Earth

Notes:

[1] An HI region (pronounced "H-one") contains a lot of neutral hydrogen, an HII (pronounced "H-two") lots of ionised hydrogen, and a H2 region molecular hydrogen.
Notes for editors

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

Links:

Images of Hubble: http://www.spacetelescope.org/images/archive/category/spacecraft/

Hubble Heritage release: http://heritage.stsci.edu/2014/18/

NASA release: http://hubblesite.org/newscenter/archive/releases/2014/18

Tarantula nebulae (heic1206): http://spacetelescope.org/news/heic1206/

Horsehead nebulae (heic1307): http://spacetelescope.org/news/heic1307/

Planetary nebula NGC 5189 (heic1220): http://www.spacetelescope.org/news/heic1220/

Hubblecast 73: Hubble revisits the Monkey Head Nebula for 24th birthday: http://www.spacetelescope.org/videos/heic1406a/

Images, Text, Credits: NASA, ESA, and the Hubble Heritage Team (STScI/AURA) and J. Hester, R. Crisp / Digitized Sky Survey (DSS) / Palomar/Caltech / Videos: NASA, ESA, and G. Bacon (STScI). Acknowledgement: A. Fujii, the Digitized Sky Survey 2, and the Hubble Heritage Team (STScI/AURA) / M. Kornmesser.

Best regards, Orbiter.ch

dimanche 16 mars 2014

NASA Completes this Year's Flights in Search of Climate Change Clues















NASA - ATTREX Misson logo.


March 16, 2014


Image above: NASA's Global Hawk No. 872 flares for landing at Andersen Air Force Base on Guam to begin the 2014 ATTREX climate-change mission Jan. 17. The two-month-long airborne science flight campaign wrapped up with the aircraft's return to NASA's Armstrong Flight Research Center March 14. (U.S. Air Force).

NASA's Global Hawk research aircraft returned to its base at NASA's Armstrong Flight Research Center at Edwards Air Force Base, Calif., early Friday morning March 14, marking the completion of flights in support of this year's Airborne Tropical Tropopause Experiment (ATTREX), a multi-year NASA airborne science campaign.

On Feb. 13, the autonomously operated aircraft began conducting science flights from Andersen Air Force Base on Guam in the western Pacific region on a mission to track changes in the upper atmosphere and help researchers understand how these changes affect Earth's climate.

"The western Pacific region is critical for establishing the humidity of the air entering the stratosphere," said Eric Jensen, ATTREX principal investigator at NASA’s Ames Research Center at Moffett Field, Calif.

ATTREX measures the moisture levels and chemical composition of upper regions of the lowest layer of Earth's atmosphere, a region where even small changes can significantly impact climate. Scientists will use the data to better understand physical processes occurring in this part of the atmosphere and help make more accurate climate predictions.


Image above: Mario Rana of Science Systems and Applications, Inc., at NASA Langley (foreground) and Jim Podolske of NASA Ames check out data recorded by the Diode Laser Hygrometer installed on NASA's Global Hawk following a 2014 ATTREX mission flight March 9 over the western Pacific Ocean. (NASA / Dave Fratello).

Studies show even slight changes in the chemistry and amount of water vapor in the stratosphere, the same region that is home to the ozone layer that protects life on Earth from the damaging effects of ultraviolet radiation, can affect climate significantly by absorbing thermal radiation rising from the surface. Predictions of stratospheric humidity changes are uncertain because of gaps in the understanding of the physical processes occurring in the tropical tropopause layer.

ATTREX is studying moisture and chemical composition from altitudes of 45,000 to 60,000 feet in the tropical tropopause, which is the transition layer between the troposphere, the lowest part of the atmosphere, and the stratosphere, which extends to roughly 30 miles above Earth's surface. Scientists consider the tropical tropopause to be the gateway for water vapor, ozone and other gases that enter the stratosphere. For this mission, the Global Hawk carries instruments that will sample the tropopause near the equator over the Pacific Ocean.

ATTREX scientists installed 13 research instruments on NASA's Global Hawk 872. Some of these instruments capture air samples while others use remote sensing to analyze clouds, temperature, water vapor, gases and solar radiation.

This year, ATTREX conducted seven long-duration science flights totaling 121 hours, averaging more than 17 hours per flight. This year's flights bring the total hours flown in support of ATTREX to 297 hours since 2011.


Image above: A team of NOAA researchers checks out the UAS Chromatograph for Atmospheric Trace Species (UCATS) instrument installed in NASA's unmanned Global Hawk for the ATTREX mission. (NASA photo).

Jensen and Project Manager Dave Jordan of Ames lead the ATTREX mission. It includes investigators from Ames and three other NASA facilities: Langley Research Center in Hampton, Va., Goddard Space Flight Center in Greenbelt, Md., and the Jet Propulsion Laboratory in Pasadena, Calif. The team also includes investigators from the National Oceanic and Atmospheric Administration, the National Center for Atmospheric Research, the University of California at Los Angeles, the University of Miami, the University of Heidelberg, and private industry.

ATTREX is one of the first research missions of NASA's new Earth Venture project. These small and targeted science investigations complement NASA's broader science research satellite missions. The Earth Venture missions are part of NASA's Earth System Science Pathfinder Program managed by Langley.

NASA monitors Earth's vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

Related link:

Airborne Tropical Tropopause Experiment (ATTREX): http://espo.nasa.gov/missions/attrex

For more information about NASA's Earth science activities in 2014, visit:
http://www.nasa.gov/earthrightnow

Images (mentioned), Text, Credits: NASA Ames Research Center / Rachel Hoover.

Cheers, Orbiter.ch

Jade Rabbit will remain stationary for the rest of its life - however long that may be










CNSA - China National Space Administration logo.

March 16, 2014

China’s troubled Yutu (Jade Rabbit) rover has woken up again after its third lunar night to begin its fourth day on the Moon despite the problems with its motor driving circuit that persisted when the rover headed into sleep mode on February 23.

Sunrise at Mare Imbrium occurred around 11 UTC on March 10, but with Yutu unable to tilt one of its solar panels toward the sun, it was suspected that the rover could not wake up as early in the lunar day as it would if it was healthy. On March 13, @uhf_satcom who had received signals from Chang’e 3 & Yutu earlier reported that Yutu was transmitting a signal that appeared to be a low-rate data downlink from the rover.

@uhf_satcom also reported that China was uplinking commands to Yutu as the uplink signal was reflected from the Moon and detected by their tracking station. Later on Thursday, it was reported that the rover had responded to commands & showed a strong downlink signal similar to those seen before the last lunar night.

Yutu (Jade Rabbit) rover on the Moon surface

Official Chinese news outlets have not reported of Yutu’s awakening yet, but the reception of the rover’s signal confirms that the Jade Rabbit is still alive & officially exceeding its expected life time on the lunar surface. The rover was designed to survive for three lunar days, but teams hoped it would be able to continue operating longer than that. Still, if the problems related to the rover’s motor-driving system can not be solved, Yutu will remain stationary for the rest of its life - however long that may be.

The problem emerged back on January 25 when Yutu was about to enter sleep mode for the mission’s second lunar night and left the rover in a bad thermal configuration with its mast and both solar panels extended.

Mission controllers were ready to pronounce the rover dead as it was not expected that Yutu would survive the cold temperatures of the lunar night without folding up its mast and shielding it & the rover body with one of the solar panels. On February 12, Yutu woke up and was still operational, but the problem with its control circuitry persisted throughout the third lunar day and troubleshooting efforts were not successful. It remains to be seen whether the rover will be able to drive again and how long it can endure the harsh environment on the lunar surface.

For more information about China National Space Administration (CNSA), visit: http://www.cnsa.gov.cn/n615709/cindex.html

Images, Text, Credits: Spaceflight101./China Academy of Sciences/Xinhua.

Greetings, Orbiter.ch