samedi 13 août 2011
Hubble Offers a Dazzling 'Necklace'
NASA - Hubble Space Telescope patch.
August 13, 2011
The Necklace Nebula is located 15,000 light-years away in the constellation Sagitta (the Arrow). In this composite image, taken on July 2, 2011, Hubble's Wide Field Camera 3 captured the glow of hydrogen (blue), oxygen (green), and nitrogen (red). Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA).
A giant cosmic necklace glows brightly in this NASA Hubble Space Telescope image.
The object, aptly named the Necklace Nebula, is a recently discovered planetary nebula, the glowing remains of an ordinary, Sun-like star. The nebula consists of a bright ring, measuring 12 trillion miles wide, dotted with dense, bright knots of gas that resemble diamonds in a necklace.
A pair of stars orbiting close together produced the nebula, also called PN G054.2-03.4. About 10,000 years ago one of the aging stars ballooned to the point where it engulfed its companion star. The smaller star continued orbiting inside its larger companion, increasing the giant’s rotation rate.
The bloated companion star spun so fast that a large part of its gaseous envelope expanded into space. Due to centrifugal force, most of the gas escaped along the star’s equator, producing a ring. The embedded bright knots are dense gas clumps in the ring.
The pair is so close, only a few million miles apart, they appear as one bright dot in the center. The stars are furiously whirling around each other, completing an orbit in a little more than a day.
The Necklace Nebula is located 15,000 light-years away in the constellation Sagitta. In this composite image, taken on July 2, Hubble’s Wide Field Camera 3 captured the glow of hydrogen (blue), oxygen (green), and nitrogen (red).
Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA).
Hubble is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy Inc. in Washington.
For images and more information about Hubble, visit:
ESA Hubble website: http://www.spacetelescope.org/
Image (mentioned), Text, Credit: NASA / Space Telescope Science Institute, Baltimore, Md. / Donna Weaver / Ray Villard.
Publié par Orbiter.ch à 04:21
vendredi 12 août 2011
A Cosmic Exclamation Point
NASA - Chandra X-ray Observatory patch.
August 12, 2011
VV 340, also known as Arp 302, provides a textbook example of colliding galaxies seen in the early stages of their interaction. The edge-on galaxy near the top of the image is VV 340 North and the face-on galaxy at the bottom of the image is VV 340 South. Millions of years later these two spirals will merge -- much like the Milky Way and Andromeda will likely do billions of years from now. Data from NASA's Chandra X-ray Observatory (purple) are shown here along with optical data from the Hubble Space Telescope (red, green, blue). VV 340 is located about 450 million light years from Earth.
Because it is bright in infrared light, VV 340 is classified as a Luminous Infrared Galaxy (LIRG). These observations are part of the Great Observatories All-Sky LIRG Survey (GOALS) combining data from Chandra, Hubble, NASA's Spitzer Space Telescope and Galaxy Evolution Explorer (GALEX) and ground-based telescopes. The survey includes over two hundred LIRGs in the local Universe. A chief motivation of this study is to understand why LIRGs emit so much infrared radiation. These galaxies generate energy at a rate this is tens to hundreds of times larger than that emitted by a typical galaxy. An actively growing supermassive black hole or an intense burst of star formation is often invoked as the most likely source of the energy.
Work on the full GOALS survey is ongoing, but preliminary analysis of data for VV 340 provides a good demonstration of the power of observing with multiple observatories. The Chandra data show that the center of VV 340 North likely contains a rapidly growing supermassive black hole that is heavily obscured by dust and gas. The infared emission of the galaxy pair, as observed by Spitzer, is dominated by VV 340 North, and also provides evidence for a growing supermassive black hole. However, only a small fraction of the infrared emission is generated by this black hole.
By contrast most of the ultraviolet and short wavelength optical emission in the galaxy pair -- as observed by GALEX and HST -- comes from VV 340 South. This shows that VV 340 South contains a much higher level of star formation. (The Spitzer and GALEX images are not shown here because they strongly overlap with the optical and X-ray images, but they are shown in a separate composite image.) VV 340 appears to be an excellent example of a pair of interacting galaxies evolving at different rates.
These results on VV 340 were published in the June 2009 issue of the Publications of the Astronomical Society of the Pacific. The lead author was Lee Armus from the Spitzer Science Center in Pasadena, CA.
Read more/access all images: http://chandra.harvard.edu/photo/2011/vv340/
Image, Text, Credit: X-ray NASA / CXC / IfA / D.Sanders et al; Optical NASA / STScI / NRAO / A.Evans et al.
Publié par Orbiter.ch à 14:58
jeudi 11 août 2011
Cosmic Inkblot Test
NASA - SPITZER Space Telescope logo.
August 11, 2011
The Dumbbell Nebula, also known as Messier 27, pumps out infrared light in this image from NASA's Spitzer Space Telescope. The nebula was named after its resemblance to a dumbbell when seen in visible light. It was discovered in 1764 by Charles Messier, who included it as the 27th member of his famous catalog of nebulous objects. Although he did not know it at the time, this was the first in a class of objects, now known as planetary nebulae, to make it into the catalog.
Planetary nebulae, historically named for their resemblance to gas-giant planets, are now known to be the remains of stars that once looked a lot like our sun. When sun-like stars die, they puff out their outer gaseous layers, which are heated by the hot core of the dead star, called a white dwarf, and shine with infrared and visible-light colors. Our own sun will blossom into a planetary nebula when it dies in about five billion years.
Image, Text, Credits: NASA / JPL-Caltech / Harvard-Smithsonian CfA.
Publié par Orbiter.ch à 14:22
mercredi 10 août 2011
A Spiral in Leo
ESO - European Southern Observatory logo.
10 August 2011
A spiral galaxy in Leo
This new picture from ESO’s Very Large Telescope shows NGC 3521, a spiral galaxy located about 35 million light years away in the constellation of Leo (The Lion). Spanning about 50 000 light-years, this spectacular object has a bright and compact nucleus, surrounded by richly detailed spiral structure.
The most distinctive features of the bright galaxy NGC 3521 are its long spiral arms that are dotted with star-forming regions and interspersed with veins of dust. The arms are rather irregular and patchy, making NGC 3521 a typical example of a flocculent spiral galaxy. These galaxies have “fluffy” spiral arms that contrast with the sweeping arms of grand-design spirals such as the famous Whirlpool galaxy or M 51, discovered by Charles Messier.
The spiral galaxy NGC 3521 in the constellation of Leo
NGC 3521 is bright and relatively close-by, and can easily be seen with a small telescope such as the one used by Messier to catalogue a series of hazy and comet-like objects in the 1700s. Strangely, the French astronomer seems to have missed this flocculent spiral even though he identified several other galaxies of similar brightness in the constellation of Leo.
It was only in the year that Messier published the final version of his catalogue, 1784, that another famous astronomer, William Herschel, discovered NGC 3521 early on in his more detailed surveys of the northern skies. Through his larger, 47-cm aperture, telescope, Herschel saw a “bright center surrounded by nebulosity,” according to his observation notes.
In this new VLT picture, colourful, yet ill defined, spiral arms replace Herschel’s “nebulosity”. Older stars dominate the reddish area in the centre while young, hot blue stars permeate the arms further away from the core.
Wide-field view of the sky around NGC 3521
Oleg Maliy, who participated ESO’s Hidden Treasures 2010 competition , selected the data from the FORS1 instrument on ESO’s VLT at the Paranal Observatory in Chile that were used to create this dramatic image. Exposures taken through three different filters that passed blue light (coloured blue), yellow/green light (coloured green), and near-infrared light (coloured red) have been combined to make this picture. The total exposure times were 300 seconds per filter. Oleg’s image of NGC 3521 was a highly ranked entry in the competition, which attracted almost 100 entries.
 ESO’s Hidden Treasures 2010 competition gave amateur astronomers the opportunity to search through ESO’s vast archives of astronomical data, hoping to find a well-hidden gem that needed polishing by the entrants. To find out more about Hidden Treasures, visit http://www.eso.org/public/outreach/hiddentreasures/.
ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive astronomical observatory. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 40-metre-class European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.
Photos of the VLT: http://www.eso.org/public/images/archive/category/paranal/
Images, Text, Credits: ESO / O. Maliy / IAU and Sky & Telescope / Digitized Sky Survey 2.
Publié par Orbiter.ch à 03:47
mardi 9 août 2011
Solar Flares: What Does It Take to Be X-Class?
NASA logo / NOAA logo labeled.
August 10, 2011
Video above: Solar flares are classified according to their strength. The smallest ones are A-class, followed by B, C, M and X, the largest. Credit: NASA / Goddard / S. Wiessinger.
Solar flares are giant explosions on the sun that send energy, light and high speed particles into space. These flares are often associated with solar magnetic storms known as coronal mass ejections (CMEs). The number of solar flares increases approximately every 11 years, and the sun is currently moving towards another solar maximum, likely in 2013. That means more flares will be coming, some small and some big enough to send their radiation all the way to Earth.
The biggest flares are known as "X-class flares" based on a classification system that divides solar flares according to their strength. The smallest ones are A-class (near background levels), followed by B, C, M and X. Similar to the Richter scale for earthquakes, each letter represents a 10-fold increase in energy output. So an X is ten times an M and 100 times a C. Within each letter class there is a finer scale from 1 to 9.
C-class and smaller flares are too weak to noticeably affect Earth. M-class flares can cause brief radio blackouts at the poles and minor radiation storms that might endanger astronauts.
And then come the X-class flares. Although X is the last letter, there are flares more than 10 times the power of an X1, so X-class flares can go higher than 9. The most powerful flare measured with modern methods was in 2003, during the last solar maximum, and it was so powerful that it overloaded the sensors measuring it. The sensors cut out at X28.
The Solar and Heliospheric Observatory (SOHO) spacecraft captured this image of a solar flare as it erupted from the sun early on Tuesday, October 28, 2003. Credit: NASA / SOHO.
The biggest X-class flares are by far the largest explosions in the solar system and are awesome to watch. Loops tens of times the size of Earth leap up off the sun's surface when the sun's magnetic fields cross over each other and reconnect. In the biggest events, this reconnection process can produce as much energy as a billion hydrogen bombs.
If they're directed at Earth, such flares and associated CMEs can create long lasting radiation storms that can harm satellites, communications systems, and even ground-based technologies and power grids. X-class flares on December 5 and December 6, 2006, for example, triggered a CME that interfered with GPS signals being sent to ground-based receivers.
The Halloween solar storms of 2003 resulted in this aurora visible in Mt. Airy, Maryland. Credit: NASA / George Varros.
NASA and NOAA – as well as the US Air Force Weather Agency (AFWA) and others -- keep a constant watch on the sun to monitor for X-class flares and their associated magnetic storms. With advance warning many satellites and spacecraft can be protected from the worst effects.
› Recent Solar Events: http://www.nasa.gov/mission_pages/sunearth/multimedia/Solar-Events.html
› Space Weather Frequently Asked Questions: http://www.nasa.gov/mission_pages/sunearth/spaceweather/index.html
› View video of 2003 Halloween Solar Storm: http://www.nasa.gov/multimedia/videogallery/index.html?media_id=17956765
Images (mentioned), Video (mentioned), Text, Credit: NASA's Goddard Space Flight Center, Karen C. Fox.
Publié par Orbiter.ch à 19:48
NASA Mars Rover Approaches Long-Term Goal
NASA - Mars Rover Exploration "Opportunity" (MER-B) patch.
August 10, 2011
NASA's Mars Exploration Rover Opportunity used its panoramic camera to capture this view of a portion of Endeavour crater's rim. NASA's Mars Exploration Rover Opportunity used its panoramic camera (Pancam) to capture this view of a portion of Endeavour crater's rim after a drive during the rover's 2,676th Martian day, or sol, of working on Mars (Aug. 4, 2011). Image Credit: NASA / JPL-Caltech / Cornell / ASU.
The NASA Mars rover Opportunity has gained a view of Endeavour crater from barely more than a football-field's distance away from the rim. The rim of Endeavour has been the mission's long-term goal since mid-2008.
Endeavour offers the setting for plenty of productive work by Opportunity. The crater is 14 miles (22 kilometers) in diameter -- more than 25 times wider than Victoria crater, an earlier stop that Opportunity examined for two years. Observations by orbiting spacecraft indicate that the ridges along Endeavour's western rim expose rock outcrops older than any Opportunity has seen so far. The selected location for arrival at the rim, "Spirit Point," is at the southern tip of one of those ridges, "Cape York," on the western side of Endeavour.
Mars Rover Exploration Opportunity. Image Credit: NASA / JPL-Caltech
NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover Project for the NASA Science Mission Directorate, Washington. More information about the rovers is online at: http://www.nasa.gov/rovers
Images (mentioned), Text, Credit: NASA / JPL / Guy Webster.
Publié par Orbiter.ch à 19:18
CERN experiment weighs antimatter with unprecedented accuracy
CERN - European Organization for Nuclear Research logo.
In a paper published 28 July 2011 in the journal Nature, the Japanese-European ASACUSA experiment at CERN reported a new measurement of the antiproton’s mass accurate to about one part in a billion. Precision measurements of the antiproton mass provide an important way to investigate nature’s apparent preference for matter over antimatter.
The ASACUSA experiment
“This is a very satisfying result,” said Masaki Hori, a project leader in the ASACUSA collaboration. “It means that our measurement of the antiproton’s mass relative to the electron is now almost as accurate as that of the proton.”
Ordinary protons constitute about half of the world around us, ourselves included. With so many protons around it would be natural to assume that the proton mass should be measurable to greater accuracy than that of antiprotons. After today’s result, this remains true but only just. In future experiments, ASACUSA expects to improve the accuracy of the antiproton mass measurement to far better than that for the proton. Any difference between the mass of protons and antiprotons would be a signal for new physics, indicating that the laws of nature could be different for matter and antimatter.
Image above: The ASACUSA experiment at CERN's AD antiproton decelerator catches antiprotons in helium, where the antiprotons replace electrons, giving exotics atoms.
To make these measurements antiprotons are first trapped inside helium atoms, where they can be ‘tickled’ with a laser beam. The laser frequency is then tuned until it causes the antiprotons to make a quantum jump within the atoms, and from this frequency the antiproton mass can be calculated. However, an important source of imprecision comes from the fact that the atoms jiggle around, so that those moving towards and away from the beam experience slightly different frequencies.
A similar effect is what causes the siren of an approaching ambulance to apparently change pitch as it passes you in the street. In their previous measurement in 2006, the ASACUSA team used just one laser beam, and the achievable accuracy was dominated by this effect. This time they used two beams moving in opposite directions, with the result that the jiggle for the two beams partly cancelled out, resulting in a four times better accuracy.
ASACUSA Experiment - Antiprotons weighed with unprecedented precision
“Imagine measuring the weight of the Eiffel tower” said Hori. “The accuracy we’ve achieved here is roughly equivalent to making that measurement to within less than the weight of a sparrow perched on top. Next time it will be a feather.”
Video: CERN News ASACUSA Experiment: http://cdsweb.cern.ch/record/1371017
Follow CERN at:
1. 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. India, Israel, Japan, the Russian Federation, the United States of America, Turkey, the European Commission and UNESCO have Observer status.
Images, Video, Text, Credit: CERN.
Best regards, Orbiter.ch
Publié par Orbiter.ch à 18:48
Japan tsunami caused icebergs to break off in Antarctica
ESA - ENVISAT logo.
9 August 2011
The effects of the March 2011 earthquake and subsequent tsunami that devastated areas of Japan can be seen as far away as Antarctica. Satellite images show new icebergs were created after the tsunami hit the Sulzberger Ice Shelf.
Using radar images acquired by ESA’s Envisat satellite, a NASA team was able to spot the icebergs – the largest measuring about 6.5 by 9.5 km in surface area and about 80 m in thickness.
The findings linking the tsunami to the calving event by NASA’s Kelly Brunt, a cryosphere specialist at Goddard Space Flight Center in Greenbelt, Maryland, and her colleagues were published in the online Journal of Glaciology on Monday.
Sulzberger Ice Shelf
The Tohoku 9.0 magnitude earthquake that stuck off the coast of Japan triggered a tsunami with giant waves. The waves then propagated through the Pacific Ocean over 13 000 km south to the Sulzberger Ice Shelf in Antarctica, causing large chunks of ice to break off and float into the Ross Sea.
The waves were likely only about 30 cm high when they reached the Sulzberger shelf, but the consistency of the waves created enough stress to cause the break off.
“These new findings in Antarctica demonstrate that satellite observations are essential to understanding the mechanisms and effects associated with natural disasters,” said Henri Laur, ESA Envisat Mission Manager.
“The Envisat data of the Tohoku earthquake have also been exploited intensively by scientists to provide a detailed map of the surface deformation in Japan a few weeks after the earthquake.”
The Advanced Synthetic Aperture Radar on board Envisat can capture images in all weather and lighting conditions, and is therefore essential for observing polar areas.
Every day, Envisat gathers radar images of Antarctica. Those images are freely available to anyone using the ESA MIRAVI web site.
Journal of Glaciology: http://www.igsoc.org/journal/
The International Charter Space and Major Disasters: http://www.disasterscharter.org/
MIRAVI: Earth live: http://miravi.eo.esa.int/en/
Images, Text, Credit: ESA.
Publié par Orbiter.ch à 09:01
lundi 8 août 2011
NASA Researchers: DNA Building Blocks Can Be Made in Space
NASA-funded researchers have evidence that some building blocks of DNA, the molecule that carries the genetic instructions for life, found in meteorites were likely created in space. The research gives support to the theory that a "kit" of ready-made parts created in space and delivered to Earth by meteorite and comet impacts assisted the origin of life.
"People have been discovering components of DNA in meteorites since the 1960's, but researchers were unsure whether they were really created in space or if instead they came from contamination by terrestrial life," said Dr. Michael Callahan of NASA's Goddard Space Flight Center, Greenbelt, Md. "For the first time, we have three lines of evidence that together give us confidence these DNA building blocks actually were created in space." Callahan is lead author of a paper on the discovery appearing in Proceedings of the National Academy of Sciences of the United States of America.
Video above: NASA-funded researchers have evidence that some building blocks of DNA, the molecule that carries the genetic instructions for life, found in meteorites were likely created in space. The research gives support to the theory that a "kit" of ready-made parts created in space and delivered to Earth by meteorite and comet impacts assisted the origin of life. (Credit: NASA's Goddard Space Flight Center).
The discovery adds to a growing body of evidence that the chemistry inside asteroids and comets is capable of making building blocks of essential biological molecules. For example, previously, these scientists at the Goddard Astrobiology Analytical Laboratory have found amino acids in samples of comet Wild 2 from NASA’s Stardust mission, and in various carbon-rich meteorites. Amino acids are used to make proteins, the workhorse molecules of life, used in everything from structures like hair to enzymes, the catalysts that speed up or regulate chemical reactions.
In the new work, the Goddard team ground up samples of twelve carbon-rich meteorites, nine of which were recovered from Antarctica. They extracted each sample with a solution of formic acid and ran them through a liquid chromatograph, an instrument that separates a mixture of compounds. They further analyzed the samples with a mass spectrometer, which helps determine the chemical structure of compounds.
Image above: Meteorites contain a large variety of nucleobases, an essential building block of DNA. (Artist concept credit: NASA's Goddard Space Flight Center / Chris Smith).
The team found adenine and guanine, which are components of DNA called nucleobases, as well as hypoxanthine and xanthine. DNA resembles a spiral ladder; adenine and guanine connect with two other nucleobases to form the rungs of the ladder. They are part of the code that tells the cellular machinery which proteins to make. Hypoxanthine and xanthine are not found in DNA, but are used in other biological processes.
Also, in two of the meteorites, the team discovered for the first time trace amounts of three molecules related to nucleobases: purine, 2,6-diaminopurine, and 6,8-diaminopurine; the latter two almost never used in biology. These compounds have the same core molecule as nucleobases but with a structure added or removed.
It's these nucleobase-related molecules, called nucleobase analogs, which provide the first piece of evidence that the compounds in the meteorites came from space and not terrestrial contamination. "You would not expect to see these nucleobase analogs if contamination from terrestrial life was the source, because they're not used in biology, aside from one report of 2,6-diaminopurine occurring in a virus (cyanophage S-2L)," said Callahan. "However, if asteroids are behaving like chemical 'factories' cranking out prebiotic material, you would expect them to produce many variants of nucleobases, not just the biological ones, due to the wide variety of ingredients and conditions in each asteroid."
The second piece of evidence involved research to further rule out the possibility of terrestrial contamination as a source of these molecules. The team also analyzed an eight-kilogram (21.4-pound) sample of ice from Antarctica, where most of the meteorites in the study were found, with the same methods used on the meteorites. The amounts of the two nucleobases, plus hypoxanthine and xanthine, found in the ice were much lower -- parts per trillion -- than in the meteorites, where they were generally present at several parts per billion. More significantly, none of the nucleobase analogs were detected in the ice sample. One of the meteorites with nucleobase analog molecules fell in Australia, and the team also analyzed a soil sample collected near the fall site. As with the ice sample, the soil sample had none of the nucleobase analog molecules present in the meteorite.
Thirdly, the team found these nucleobases -- both the biological and non-biological ones -- were produced in a completely non-biological reaction. "In the lab, an identical suite of nucleobases and nucleobase analogs were generated in non-biological chemical reactions containing hydrogen cyanide, ammonia, and water. This provides a plausible mechanism for their synthesis in the asteroid parent bodies, and supports the notion that they are extraterrestrial," says Callahan.
"In fact, there seems to be a 'goldilocks' class of meteorite, the so-called CM2 meteorites, where conditions are just right to make more of these molecules," adds Callahan.
The team includes Callahan and Drs. Jennifer C. Stern, Daniel P. Glavin, and Jason P. Dworkin of NASA Goddard's Astrobiology Analytical Laboratory; Ms. Karen E. Smith and Dr. Christopher H. House of Pennsylvania State University, University Park, Pa.; Dr. H. James Cleaves II of the Carnegie Institution of Washington, Washington, DC; and Dr. Josef Ruzicka of Thermo Fisher Scientific, Somerset, N.J. The research was funded by the NASA Astrobiology Institute, the Goddard Center for Astrobiology, the NASA Astrobiology: Exobiology and Evolutionary Biology Program, and the NASA Postdoctoral Program.
Related videos from NASA Goddard's Scientific Visualization Studio: http://svs.gsfc.nasa.gov/vis/a010000/a010800/a010810/
Image (mentioned), Video (mentioned), Text, Credit: Bill Steigerwald, NASA's Goddard Space Flight Center.
Publié par Orbiter.ch à 17:22
Ariane 5’s fourth launch of 2011
Arianespace logo labeled.
8 August 2011
Ariane 5 flight VA203
Early this morning, an Ariane 5 launcher lifted off from Europe’s Spaceport in French Guiana on its mission to place two telecommunications satellites, Astra-1N and BSAT-3c/JCSAT-110R, into their planned transfer orbits.
The target injection orbit had a perigee altitude of 249.6 km, an apogee altitude at injection of 35 959 km and an inclination of 2º.
The satellites were accurately injected into their transfer orbits about 27 minutes and 38 minutes after liftoff, respectively.
Astra-1N will be positioned above the equator at 19.2°E. It will provide direct-to-home television broadcast services in Europe.
BSAT-3c/JCSAT-110R, to be positioned over 110°E, will provide mainly television broadcast services in Japan.
The payload mass for this launch was 9095 kg; the satellites totalled 8240 kg, with payload adapters and dispensers making up the additional 855 kg.
Ariane 5 flight VA203
VA203 flight timeline
The Ariane 5’s cryogenic, liquid-propellant main engine was ignited first. Seven seconds later, the solid-propellant boosters also fired, and the vehicle lifted off a fraction of a second later.
The solid boosters were jettisoned 2 min 21 sec after main engine ignition, and the fairing protecting the payload during the climb through Earth’s atmosphere was discarded at 3 min 12 sec.
The launcher’s main engine was shut down at 8 min 52 sec; six seconds later, the main cryogenic stage separated from the upper stage and its payload.
Four seconds after main stage separation, the engine of the cryogenic upper stage was ignited to continue the journey. The engine was shut down at 24 min 58 sec into the flight, at which point the vehicle was travelling at 9356 m/s (33 682 km/h) at an altitude of 657 km. The conditions for geostationary transfer orbit injection had been achieved.
At 27 min 12 sec after main engine ignition, Astra-1N separated from the upper stage, followed by BSAT-3c/JCSAT-110R at 38 min 11 sec. Ariane 5’s flight operations were completed 49 min 41 sec after main engine ignition.
Credits: ESA / Arianespace.
Best regards, Orbiter.ch
Publié par Orbiter.ch à 08:56
Mars’ northern polar regions in transition
ESA - Mars Express Mission patch.
8 August 2011
Mars’ northern polar regions (click on the images for enlarge)
A newly released image from ESA’s Mars Express shows the north pole of Mars during the red planet’s summer solstice. All the carbon dioxide ice has gone, leaving just a bright cap of water ice.
This image was captured by the orbiter’s High-Resolution Stereo Camera on 17 May 2010 and shows part of the northern polar region of Mars during the summer solstice. The solstice is the longest day and the beginning of the summer for the planet’s northern hemisphere.
The ice shield is covered by frozen water and carbon dioxide ice in winter and spring but by this point in the martian year all of the carbon dioxide ice has warmed and evaporated into the planet’s atmosphere.
Only water ice is left behind, which shows up as bright white areas in this picture. From these layers, large bursts of water vapour are occasionally released into the atmosphere.
Mars’ northern polar regions in context
The polar ice follows the seasons. In winter, part of the atmosphere recondenses as frost and snow on the northern cap. These seasonal deposits can extend as far south as 45°N latitude and be up to a metre thick.
Another phenomenon occurs on the curved scarps of the northern polar cap, such as the Rupes Tenuis slope (on the left of this image). During spring, the seasonal carbon dioxide layer is covered by water frost. At certain times, winds remove the the millimetre-thick top layer of frozen water, revealing the carbon dioxide ice below.
These processes bear witness to a dynamic water cycle on Mars and may lead to the varying accumulation of water ice over the polar cap.
Other noticeable features in this image include the Chasma Boreale canyon, coloured deposits and a large dune field.
Chasma Boreale is about 2 km deep, 580 km long and about 100 km wide. Its walls allow a perfect view into the strata within the deposits. There are impact craters on the canyon floor, some heavily covered by sand and some partly exhumed.
Dark and light-toned deposits can be seen as a fine and regular covering. The darker sediments have been dropped by the winds during spring dust storms. The patterns are created when the deposits change in quantity according to the seasons.
Northern high resolution
The polar cap is surrounded by a large dune field, parts of which extend 600 km to the south.
Mars Express will soon be using its radar to probe the northern polar cap in three dimensions. Since the radar antenna was deployed in mid-2005, the team have been waiting for the right conditions to observe the region.
The radar works best at night when the electrical interference from the planet’s atmosphere is at a minimum. An excellent opportunity to observe the cap’s shape, depth and composition occurs in August and September 2011.
Stay tuned for new results!
Traces of Martian life: Ice on Mars
High Resolution Stereo Camera: http://berlinadmin.dlr.de/Missions/express/indexeng.shtml
Behind the lens: http://www.esa.int/SPECIALS/Mars_Express/SEMSXE1PGQD_0.html
Frequently asked questions: http://www.esa.int/SPECIALS/Mars_Express/SEM76D9OY2F_0.html
ESA Planetary Science archive (PSA): http://www.rssd.esa.int/PSA
NASA Planetary Data System: http://pds-geosciences.wustl.edu/missions/mars_express/hrsc.htm
HRSC data viewer: http://hrscview.fu-berlin.de/
Images, Text, Credits: ESA / DLR / FU Berlin (G. Neukum) / NASA MGS MOLA Science Team.
Publié par Orbiter.ch à 07:54
NASA'S Juno Spacecraft Launches To Jupiter
NASA - JUNO Mission patch.
August 08, 2011
NASA's solar-powered Juno spacecraft lifted off from Cape Canaveral Air Force Station at 12:25 p.m. EDT Friday 5 August to begin a five-year journey to Jupiter.
JUNO Lifts Off
Juno's detailed study of the largest planet in our solar system will help reveal Jupiter's origin and evolution. As the archetype of giant gas planets, Jupiter can help scientists understand the origin of our solar system and learn more about planetary systems around other stars.
Juno Launches to Jupiter
After Juno's launch aboard an Atlas V rocket, mission controllers now await telemetry from the spacecraft indicating it has achieved its proper orientation, and that its massive solar arrays, the biggest on any NASA deep-space probe, have deployed and are generating power.
"We are on our way, and early indications show we are on our planned trajectory," said Jan Chodas, Juno project manager at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "We will know more about Juno's status in a couple hours after its radios are energized and the signal is acquired by the Deep Space Network antennas at Canberra."
Juno will cover the distance from Earth to the moon (about 250,000 miles or 402,236 kilometers) in less than one day's time. It will take another five years and 1,740 million miles (2,800 million kilometers) to complete the journey to Jupiter. The spacecraft will orbit the planet's poles 33 times and use its collection of eight science instruments to probe beneath the gas giant's obscuring cloud cover to learn more about its origins, structure, atmosphere, and magnetosphere, and look for a potential solid planetary core.
With four large moons and many smaller moons, Jupiter forms its own miniature solar system. Its composition resembles a star's, and if it had been about 80 times more massive, the planet could have become a star instead.
"Jupiter is the Rosetta Stone of our solar system," said Scott Bolton, Juno's principal investigator from the Southwest Research Institute in San Antonio. "It is by far the oldest planet, contains more material than all the other planets, asteroids and comets combined and carries deep inside it the story of not only the solar system but of us. Juno is going there as our emissary -- to interpret what Jupiter has to say."
Juno's name comes from Greek and Roman mythology. The god Jupiter drew a veil of clouds around himself to hide his mischief, and his wife, the goddess Juno, was able to peer through the clouds and reveal Jupiter's true nature.
The NASA Deep Space Network, or DSN, is an international network of antennas that supports interplanetary spacecraft missions and radio and radar astronomy observations for the exploration of the solar system and the universe. The network also supports selected Earth-orbiting missions.
NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio. The Juno mission is part of the New Frontiers Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems, Denver, built the spacecraft. Launch management for the mission is the responsibility of NASA's Launch Services Program at the Kennedy Space Center in Florida.
For more information about Juno, visit: http://www.nasa.gov/juno and http://missionjuno.swri.edu
Images, Video, Text, Credit: NASA / JPL-Caltech.
Publié par Orbiter.ch à 07:38
NASA Spacecraft Data Suggest Water Flowing On Mars
NASA - Mars Reconnaissance Orbiter (MRO) patch.
August 08, 2011
Observations from NASA's Mars Reconnaissance Orbiter (MRO) have revealed possible flowing water during the warmest months on Mars.
"NASA's Mars Exploration Program keeps bringing us closer to determining whether the Red Planet could harbor life in some form," NASA Administrator Charles Bolden said, "and it reaffirms Mars as an important future destination for human exploration."
Dark, finger-like features appear and extend down some Martian slopes during late spring through summer, fade in winter, and return during the next spring. Repeated observations have tracked the seasonal changes in these recurring features on several steep slopes in the middle latitudes of Mars' southern hemisphere.
An image combining orbital imagery with 3-D modeling shows flows that appear in spring and summer on a slope inside Mars' Newton crater. Image credit: NASA / JPL-Caltech/Univ. of Arizona.
"The best explanation for these observations so far is the flow of briny water," said Alfred McEwen of the University of Arizona, Tucson. McEwen is the principal investigator for the orbiter's High Resolution Imaging Science Experiment (HiRISE) and lead author of a report about the recurring flows published in Thursday's edition of the journal Science.
Some aspects of the observations still puzzle researchers, but flows of liquid brine fit the features' characteristics better than alternate hypotheses. Saltiness lowers the freezing temperature of water.
Sites with active flows get warm enough, even in the shallow subsurface, to sustain liquid water that is about as salty as Earth's oceans, while pure water would freeze at the observed temperatures.
"These dark lineations are different from other types of features on Martian slopes," said MRO project scientist Richard Zurek of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Repeated observations show they extend ever farther downhill with time during the warm season."
This series of images shows warm-season features that might be evidence of salty liquid water active on Mars today. Image credit: NASA / JPL-Caltech / Univ. of Arizona. Animated image link: http://www.nasa.gov/images/content/577360main_pia14472-full-new.gif
The features imaged are only about 0.5 to 5 yards or meters wide, with lengths up to hundreds of yards. The width is much narrower than previously reported gullies on Martian slopes. However, some of those locations display more than 1,000 individual flows. Also, while gullies are abundant on cold, pole-facing slopes, these dark flows are on warmer, equator-facing slopes.
The images show flows lengthen and darken on rocky equator-facing slopes from late spring to early fall. The seasonality, latitude distribution and brightness changes suggest a volatile material is involved, but there is no direct detection of one. The settings are too warm for carbon-dioxide frost and, at some sites, too cold for pure water. This suggests the action of brines which have lower freezing points. Salt deposits over much of Mars indicate brines were abundant in Mars' past. These recent observations suggest brines still may form near the surface today in limited times and places.
When researchers checked flow-marked slopes with the orbiter's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), no sign of water appeared. The features may quickly dry on the surface or could be shallow subsurface flows.
"The flows are not dark because of being wet," McEwen said. "They are dark for some other reason."
A flow initiated by briny water could rearrange grains or change surface roughness in a way that darkens the appearance. How the features brighten again when temperatures drop is harder to explain.
This map of Mars shows relative locations of three types of findings related to salt or frozen water, plus a new type of finding that may be related to both salt and water. Image Credit: NASA / JPL-Caltech / ASU / UA / LANL / MSSS.
"It's a mystery now, but I think it's a solvable mystery with further observations and laboratory experiments," McEwen said.
These results are the closest scientists have come to finding evidence of liquid water on the planet's surface today. Frozen water, however has been detected near the surface in many middle to high-latitude regions. Fresh-looking gullies suggest slope movements in geologically recent times, perhaps aided by water. Purported droplets of brine also appeared on struts of the Phoenix Mars Lander. If further study of the recurring dark flows supports evidence of brines, these could be the first known Martian locations with liquid water.
Possible Water Flows on Mars
MRO is managed by JPL for NASA's Science Mission Directorate in Washington. The University of Arizona's Lunar and Planetary Laboratory operates HiRISE. The camera was built by Ball Aerospace & Technologies Corp. in Boulder, Colo. Johns Hopkins University Applied Physics Laboratory in Laurel, Md., provided and operates CRISM.
For more information about MRO, visit: http://www.nasa.gov/mro
Image gallery: http://www.nasa.gov/mission_pages/MRO/multimedia/gallery/gallery-index.html
Images (mentioned), Video, Text, Credits: NASA / JPL-Caltech.
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Publié par Orbiter.ch à 07:13
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