vendredi 20 septembre 2013

NASA's Deep Impact Produced Deep Results

NASA - Deep Impact Extended  Investigation 2005 patch.

Sept 20, 2013

The image depicts the first moments after Deep Impact's probe interfaced with comet Tempel 1. Image Credit: NASA/JPL-Caltech/UMD.

Launched on a clear winter day in January 2005, NASA's Deep Impact spacecraft spanned 268 million miles (431 million kilometers) of deep space in 172 days, then reached out and touched comet Tempel 1. The collision between the coffee table-sized impactor and city-sized comet occurred on July 4, 2005, at 1:52 a.m. EDT. This hyper-speed collision between spaceborne iceberg and copper-fortified, rocket-powered probe was the first of its kind. It was a boon to not only comet science, but to the study of the evolution of our solar system.

Image above: Deep Impact spacecraft releases the impactor (artist's impression). Image Credit: ESA & NASA.

The mission of Deep Impact was supposed to conclude within weeks of this July 4 cometary smackdown. Then, NASA approved a mission extension, re-enlisting the Deep Impact spacecraft for two distinct celestial targets of opportunity. EPOXI, as the mission was renamed, was a combination of the names for the two extended mission components: the extrasolar planet observations, called Extrasolar Planet Observations and Characterization (EPOCh), and the flyby of comet Hartley 2, called the Deep Impact Extended Investigation (DIXI).

This enhanced image, one of the closest taken of comet Hartley 2 by NASA's EPOXI mission, shows jets and where they originate from the surface. Image Credit: NASA/JPL-Caltech/UMD.

The Deep Impact spacecraft, history's most traveled deep-space comet hunter, provided many significant results for the science community. Here are the top five, according to the mission's principal investigator, Michael A'Hearn of the University of Maryland, College Park.

Studies of imagery showed that that the luminous flash created within a fraction of a second after Deep Impact's impactor was atomized by comet Tempel 1 was much fainter than expected.  Comparison with experimental impacts at the Vertical Gun Range at NASA Ames Research Center in Moffett Field, Calif., showed that such a faint flash was consistent only with a surface layer (depth a few times the diameter of the impactor) that was more than 75 percent empty space.  This surprisingly high porosity was in contrast with theories that predicted comets were armored with a stronger, solid crust that impeded outgassing.

Images of impact taken with the medium resolution imager. Image Credit: NASA/JPL-Caltech/UMD.

Observations of comet Tempel 1 by Deep Impact's spectrometer instrument showed that water was arising primarily at longitudes near noon and peaking near the equator, whereas most of the carbon dioxide was arising from far southern latitudes, not too far from comet Tempel 1's south pole.  This could be due to seasonal effects (southern hemisphere just going into winter darkness) or due to differences in the chemical composition in different parts of the nucleus.  During the mission extension, the EPOXI observations of comet Hartley 2 showed that the comet's smooth waist was emitting pure water, while the small end was emitting excess carbon dioxide, regardless of time of day.  This was a clear sign that chemical diversity was the important factor in a comet's chemical makeup.

For many years we have known that a handful of comets (fewer than 10 percent) produced more water vapor than should be possible by sublimation of nucleus of water ice, in which the sizes of the nuclei are known.  The flyby of comet Hartley 2 showed a large number of icy grains in the coma are driven out of the nucleus by the outgassing of carbon dioxide. These icy grains are plausibly the source of much of the water coming from the comet.

This 3-D image shows the entire nucleus of Hartley 2 with jets and an icy particle cloud. Image Credit: NASA/JPL-Caltech/UMD/Brown.

Observations of Hartley 2 by the Deep Impact spacecraft showed the importance of carbon-dioxide ice relative to carbon-monoxide ice in comets, and led to reexamination of all previous observations of these two ices in comets.  The relative abundances in short-period and long-period comets imply that the short-period comets formed under warmer conditions than did the long-period comets.  Thus, the short-period comets must have formed closer to the sun than their longer-period brethren.  This is contrary to popular belief in the astronomical community (for many decades) that the short-period comets formed in the Kuiper belt beyond Neptune, while the long-period comets formed in the vicinity of the giant planets.  The new model fits well with measurements by other astronomers of heavy water in Hartley 2, and with the newest dynamical studies of planetary migration.

The excavation of a crater on Tempel 1 was the trigger that allowed the proposal for the Stardust NExT mission to succeed.  In addition to searching for the crater formed by Deep Impact, a key goal of that Stardust-NExT mission was to measure changes in the surface of the comet over an orbital period.  This second set of measurements of Tempel 1 surface features showed that much of the evolution was in discrete, large areas, i.e., there was not a small, uniform erosion of the all parts of the surface, but rather large changes in a few places.  Thus, comets evolve in a manner anaologous to erosion – most erosion takes place in discrete events (floods that make large, local changes) rather than as a slow, continuous process.

Image above: NASA’s Deep Impact spacecraft made history flying past two of the solar system’s icy nomads. On Independence Day, 2005, Deep Impact flew past comet Tempel 1. Ten years and four months later (Oct. 4, 2010), it flew past the bowling-pin-shaped comet Hartley 2. Image Credit: NASA/JPL-Caltech/UM.

JPL, a division of the California Institute of Technology in Pasadena, manages the Deep Impact mission for NASA's Science Mission Directorate, Washington. The mission is part of the Discovery Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. The University of Maryland, College Park, is home to Michael A'Hearn, principal investigator for Deep Impact. The spacecraft was built for NASA by Ball Aerospace & Technologies Corp., Boulder, Colo.

For more information about Deep Impact, visit: .

Images (mentioned), Text, Credits: NASA / Dwayne Brown / JPL / DC Agle.

Best regards,

ESA’s Cluster satellites in closet-ever ‘dance in space’

ESA - Cluster II Mission patch.

20 September 2013

Since 2000, the four identical satellites of the Cluster quartet have been probing Earth’s magnetosphere in three dimensions. This week, two of them made their closest-ever approach, just 4 km, enabling valuable data to be acquired with unprecedented detail.

In an orbital reconfiguration that will help to maintain the mission’s life span, two of the four satellites achieved their closest-ever separation on 19 September, closing to within just 4 km of each other as they orbited at up to 23 000 km/h high above Earth.

The Cluster constellation

“We’re optimising the Cluster formation so that the separation between Cluster 1 and the duo of Cluster 3 and 4 – which are on almost identical orbits – is kept below 100 km when the formation crosses Earth’s magnetic equator,” says Detlef Sieg, working on Cluster flight dynamics at ESA’s ESOC operations centre in Darmstadt, Germany.

The formation will hold three of the four satellites close together at lower altitudes, optimising the range of science observations.

New mission record

“Following the closest-ever approach on 30 August, we achieved a new mission record with C1 and C3 yesterday, at just 4.0 km around 09:12 GMT,” says Juergen Volpp, Spacecraft Operations Manager at ESOC.

The main challenge in achieving the formation was to exclude any collision risk and to avoid further manoeuvres, which would interrupt science activities.

The Sun-Earth connection

“We can determine the satellites’ orbits with an accuracy better than 0.1 km,” says Detlef Sieg, “so we knew we could achieve the formation with sufficient allowance for safety.”

The new formation will be held until early November before the separations are increased to more than 1000 km.

Unprecedented detail

“When we started Cluster, we believed that a separation of 500 km was the smallest required by science,” says ESA’s Phillipe Escoubet, Cluster Mission Scientist.

“However, it turns out that the physical processes at very small scales are very important and this is why we have decided to decrease the separation distance to more than a factor 100 to just 4 km, as it will allow us to study electromagnetic waves in the radiation belts with unprecedented detail.”

Related links:

Exploring the Sun-Earth connection:

Cluster overview:

Cluster II operations:

Images, Text, Credits: ESA / NASA.


jeudi 19 septembre 2013

Long-Stressed Europa Likely Off-Kilter at One Time

NASA - Galileo Mission patch.

Sept 19, 2013

By analyzing the distinctive cracks lining the icy face of Europa, NASA scientists found evidence that this moon of Jupiter likely spun around a tilted axis at some point.

This tilt could influence calculations of how much of Europa's history is recorded in its frozen shell, how much heat is generated by tides in its ocean, and even how long the ocean has been liquid.

Image above: The distinctive cracks crisscrossing Europa's icy surface are clues to the stresses that this moon of Jupiter has experienced. This mosaic image was taken by NASA's Galileo satellite, which flew past this moon of Jupiter six times between 1996 and 1999. Image Credit: NASA/JPL-Caltech/University of Arizona.

"One of the mysteries of Europa is why the orientations of the long, straight cracks called lineaments have changed over time. It turns out that a small tilt, or obliquity, in the spin axis, sometime in the past, can explain a lot of what we see," said Alyssa Rhoden, a postdoctoral fellow with Oak Ridge Associated Universities who is working at NASA's Goddard Space Flight Center in Greenbelt, Md. She is the lead author of a paper in the September–October issue of Icarus that describes the results.

Europa's network of crisscrossing cracks serves as a record of the stresses caused by massive tides in the moon's global ocean. These tides occur because Europa travels around Jupiter in a slightly oval-shaped orbit. When Europa comes closer to the planet, the moon gets stretched like a rubber band, with the ocean height at the long ends rising nearly 100 feet (30 meters). That's roughly as high as the 2004 tsunami in the Indian Ocean, but it happens on a body that measures only about one-quarter of Earth's diameter. When Europa moves farther from Jupiter, it relaxes back into the shape of a ball.

The moon's ice layer has to stretch and flex to accommodate these changes, but when the stresses become too great, it cracks. The puzzling part is why the cracks point in different directions over time, even though the same side of Europa always faces Jupiter.

A leading explanation has been that Europa's frozen outer shell might rotate slightly faster than the moon orbits Jupiter. If this out-of-sync rotation does occur, the same part of the ice shell would not always face Jupiter.

Rhoden and her Goddard co-author Terry Hurford put that idea to the test using images taken by NASA's Galileo spacecraft during its nearly eight-year mission, which began in 1995. "Galileo produced many paradigm shifts in our understanding of Europa, one of which was the phenomena of out of sync rotation," said Claudia Alexander of NASA's Jet Propulsion Laboratory in Pasadena, Calif., who was the project manager when the Galileo mission ended.

Rhoden and Hurford compared the pattern of cracks in a key area near Europa's equator to predictions based on three different explanations. The first set of predictions was based on the rotation of the ice shell. The second set assumed that Europa was spinning around a tilted axis, which, in turn, made the orientation of the pole change over time. This effect, called precession, looks very much like what happens when a spinning toy top has started to slow down and wobble. The third explanation was that the cracks were laid out in random directions.

The researchers got the best performance when they assumed that precession had occurred, caused by a tilt of about one degree, and combined this effect with some random cracks, said Rhoden. Out-of-sync rotation was surprisingly unsuccessful, in part because Rhoden found an oversight in the original calculations for this model.

Images above: This close-up of the Bright Plains region near the equator of Europa reveals layer upon layer of cracks (left). By interpreting the directions of the long, straight cracks called lineaments (right), NASA scientists determined that Europa probably rotated around a tilted axis at some point. Image Credit: NASA/JPL-Caltech/University of Arizona/Goddard.

The results are compelling enough to satisfy Richard Greenberg, the University of Arizona professor who had earlier proposed the idea of out-of sync rotation.

"By extracting new information from the Galileo data, this work refines and improves our understanding of the very unusual geology of Europa," said Greenberg, who was Rhoden's undergraduate advisor and Hurford's graduate advisor.

The existence of tilt would not rule out the out-of-sync rotation, according to both Rhoden and Greenberg. But it does suggest that Europa's cracks may be much more recent than previously thought. That's because the spin pole direction may change by as much as a few degrees per day, completing one precession period over several months. On the other hand, with the leading explanation, one full rotation of the ice sheet would take roughly 250,000 years. In either case, several rotations would be needed to explain the crack patterns.

A tilt also could affect the estimates of the age of Europa's ocean. Because tidal forces are thought to generate the heat that keeps Europa's ocean liquid, a tilt in the spin axis might suggest that more heat is generated by tidal forces. This, in turn, might keep the ocean liquid longer.

NASA's Galileo satellite. Image Credit: NASA/JPL-Caltech

The analysis does not specify when the tilt would have occurred. So far, measurements have not been made of the tilt of Europa's axis, and this is one goal scientists have for Europa missions in the future.

"One of the fascinating open questions is how active Europa still is. If researchers pin down Europa's current spin axis, then our findings would allow us to assess whether the clues we are finding on the moon's surface are consistent with the present-day conditions," said Rhoden.

The Galileo mission was managed by NASA's Jet Propulsion Laboratory in Pasadena, Calif., for the agency's Science Mission Directorate.

For information about NASA and agency programs, visit:

Images (mentioned), Text, Credits: NASA / Elizabeth Zubritsky / Nancy Neal-Jones / JPL / Jia-Rui C. Cook.


Clues to the Growth of the Colossus in Coma

NASA - Chandra X-ray Observatory patch.

Sept. 19, 2013

 Clues to the Growth of the Colossus in Coma

A team of astronomers has discovered enormous arms of hot gas in the Coma cluster of galaxies by using NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton. These features, which span at least half a million light years, provide insight into how the Coma cluster has grown through mergers of smaller groups and clusters of galaxies to become one of the largest structures in the universe held together by gravity.

A new composite image, with Chandra data in pink and optical data from the Sloan Digital Sky Survey appearing in white and blue, features these spectacular arms. In this image, the Chandra data have been processed so extra detail can be seen.

The X-ray emission is from multimillion-degree gas and the optical data shows galaxies in the Coma Cluster, which contain only about one-sixth the mass in hot gas. Only the brightest X-ray emission is shown here, to emphasize the arms, but the hot gas is present over the entire field of view.

Researchers think that these arms were most likely formed when smaller galaxy clusters had their gas stripped away by the head wind created by the motion of the cluster through the hot gas, in much the same way that the headwind created by a roller coaster blows the hats off riders.

Coma is an unusual galaxy cluster because it contains not one, but two giant elliptical galaxies near its center. These two giant elliptical galaxies are probably the vestiges from each of the two largest clusters that merged with Coma in the past. The researchers also uncovered other signs of past collisions and mergers in the data.

From their length, and the speed of sound in the hot gas (about four million km/hr), the newly discovered X-ray arms are estimated to be about 300 million years old, and they appear to have a rather smooth shape. This gives researchers some clues about the conditions of the hot gas in Coma. Most theoretical models expect that mergers between clusters like those in Coma will produce strong turbulence, like ocean water that has been churned by many passing ships. Instead, the smooth shape of these lengthy arms points to a rather calm setting for the hot gas in the Coma cluster, even after many mergers.

Large-scale magnetic fields are likely responsible for the small amount of turbulence that is present in Coma. Estimating the amount of turbulence in a galaxy cluster has been a challenging problem for astrophysicists. Researchers have found a range of answers, some of them conflicting, and so observations of other clusters are needed.

Chandra X-ray Observatory

Two of the arms appear to be connected to a group of galaxies located about two million light years from the center of Coma. One or both of these arms connects to a larger structure seen in the XMM-Newton data, and spans a distance or at least 1.5 million light years. A very thin tail also appears behind one of the galaxies in Coma. This is probably evidence of gas being stripped from a single galaxy, in addition to the groups or clusters that have merged there.

These new results on the Coma cluster, which incorporate over six days worth of Chandra observing time, will appear in the September 20, 2013, issue of the journal Science. The first author of the paper is Jeremy Sanders from the Max Planck Institute for Extraterrestrial Physics in Garching, Germany. The co-authors are Andy Fabian from Cambridge University in the UK; Eugene Churazov from the Max Planck Institute for Astrophysics in Garching, Germany; Alexander Schekochihin from University of Oxford in the UK; Aurora Simionescu from Stanford University in Stanford, CA; Stephen Walker from Cambridge University in the UK and Norbert Werner from Stanford University in Stanford, CA.

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 controls Chandra's science and flight operations from Cambridge, Mass.

For more information about Chandra X-ray Observatory, visit:

Chandra on Flickr:

Images, Text, Credits: X-ray: NASA / CXC / MPE / J. Sanders et al; Optical: SDSS.


NASA Curiosity Rover Detects No Methane on Mars

NASA - Mars Science Laboratory (MSL) patch.

Sept 19, 2013

Image above: This picture shows a lab demonstration of the measurement chamber inside the Tunable Laser Spectrometer, an instrument that is part of the Sample Analysis at Mars investigation on NASA's Curiosity rover. Image Credit: NASA/JPL-Caltech.

Data from NASA's Curiosity rover has revealed the Martian environment lacks methane. This is a surprise to researchers because previous data reported by U.S. and international scientists indicated positive detections.

The roving laboratory performed extensive tests to search for traces of Martian methane. Whether the Martian atmosphere contains traces of the gas has been a question of high interest for years because methane could be a potential sign of life, although it also can be produced without biology.

"This important result will help direct our efforts to examine the possibility of life on Mars," said Michael Meyer, NASA's lead scientist for Mars exploration. "It reduces the probability of current methane-producing Martian microbes, but this addresses only one type of microbial metabolism. As we know, there are many types of terrestrial microbes that don't generate methane."

Image above: The Sample Analysis at Mars (SAM) instrument, largest of the 10 science instruments for NASA's Mars Science Laboratory mission, will examine samples of Martian rocks, soil and atmosphere for information about chemicals that are important to life and other chemical indicators about past and present environments. Image Credit: NASA/JPL-Caltech.

Curiosity analyzed samples of the Martian atmosphere for methane six times from October 2012 through June and detected none. Given the sensitivity of the instrument used, the Tunable Laser Spectrometer, and not detecting the gas, scientists calculate the amount of methane in the Martian atmosphere today must be no more than 1.3 parts per billion. That is about one-sixth as much as some earlier estimates. Details of the findings appear in the Thursday edition of Science Express.

"It would have been exciting to find methane, but we have high confidence in our measurements, and the progress in expanding knowledge is what's really important," said the report's lead author, Chris Webster of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We measured repeatedly from Martian spring to late summer, but with no detection of methane."

Webster is the lead scientist for spectrometer, which is part of Curiosity's Sample Analysis at Mars (SAM) laboratory. It can be tuned specifically for detection of trace methane. The laboratory also can concentrate any methane to increase the gas' ability to be detected. The rover team will use this method to check for methane at concentrations well below 1 part per billion.

Methane, the most abundant hydrocarbon in our solar system, has one carbon atom bound to four hydrogen atoms in each molecule. Previous reports of localized methane concentrations up to 45 parts per billion on Mars, which sparked interest in the possibility of a biological source on Mars, were based on observations from Earth and from orbit around Mars. However, the measurements from Curiosity are not consistent with such concentrations, even if the methane had dispersed globally.

Curiosity self portrait. Image Credit: NASA/JPL-Caltech

"There's no known way for methane to disappear quickly from the atmosphere," said one of the paper's co-authors, Sushil Atreya of the University of Michigan, Ann Arbor. "Methane is persistent. It would last for hundreds of years in the Martian atmosphere. Without a way to take it out of the atmosphere quicker, our measurements indicate there cannot be much methane being put into the atmosphere by any mechanism, whether biology, geology, or by ultraviolet degradation of organics delivered by the fall of meteorites or interplanetary dust particles."

The highest concentration of methane that could be present without being detected by Curiosity's measurements so far would amount to no more than 10 to 20 tons per year of methane entering the Martian atmosphere, Atreya estimated. That is about 50 million times less than the rate of methane entering Earth's atmosphere.

Curiosity landed inside Gale Crater on Mars in August 2012 and is investigating evidence about habitable environments there. JPL manages the mission and built the rover for NASA's Science Mission Directorate in Washington. The rover's Sample Analysis at Mars suite of instruments was developed at NASA's Goddard Space Flight Center in Greenbelt, Md., with instrument contributions from Goddard, JPL and the University of Paris in France.

For more information about the mission, visit and . To learn more about the SAM instrument, visit: .

Images (mentioned), Text, Credits: NASA / Dwayne Brown / JPL / Guy Webster.


Young Stars Cooking in the Prawn Nebula

ESO - European Southern Observatory logo.

19 September 2013

 Detailed view of the Prawn Nebula from ESO's VST

The glowing jumble of gas clouds visible in this new image make up a huge stellar nursery nicknamed the Prawn Nebula. Taken using the VLT Survey Telescope at ESO’s Paranal Observatory in Chile, this may well be the sharpest picture ever taken of this object. It shows clumps of hot new-born stars nestled in among the clouds that make up the nebula.

Located around 6000 light-years from Earth in the constellation of Scorpius (The Scorpion), the nebula formally known as IC 4628 is a huge region filled with gas and clumps of dark dust. These gas clouds are star-forming regions, producing brilliant hot young stars. In visible light, these stars appear as a blue-white colour, but they also emit intense radiation in other parts of the spectrum — most notably in the ultraviolet [1].

The Prawn Nebula from ESO's VST (wide crop)

It is this ultraviolet light from the stars that causes the gas clouds to glow. This radiation strips electrons from hydrogen atoms, which then later recombine and release energy in the form of light. Each chemical element emits light at characteristic colours when this process occurs, and for hydrogen the predominant colour is red. IC 4628 is an example of an HII region [2].

The Prawn Nebula is around 250 light-years across, covering an area of sky equivalent to four times that of the full Moon. Despite this huge size it has been often overlooked by observers due to its faintness and because most of its light is emitted at wavelengths where the human eye is not sensitive. The nebula is also known as Gum 56, after the Australian astronomer Colin Gum, who published a catalogue of HII regions in 1955.

Excerpts from a view of the Prawn Nebula from ESO's VST

Over the last few million years this region of sky has formed many stars, both individually and in clusters. There is a large scattered star cluster named Collinder 316 which extends over most of this image. This cluster is a part of a much larger gathering of very hot and luminous stars. Also visible are many dark structures or cavities, where interstellar matter has been blown away by the powerful winds generated by the nearby hot stars.

This image was taken by the VLT Survey Telescope (VST) at ESO’s Paranal Observatory in Chile. The VST is the largest telescope in the world designed for surveying the sky in visible light. It is a state-of-the-art 2.6-metre telescope built around the OmegaCAM camera that contains 32 CCD detectors that together create 268-megapixel images. This new 24 000-pixel-broad image is a mosaic of two such images and is one of the largest single images released by ESO so far.

The Prawn Nebula IC 4628 in the constellation of Scorpius

The picture forms part of a detailed public survey of a large part of the Milky Way called VPHAS+ that is using the power of the VST to search for new objects such as young stars and planetary nebulae. The survey will also provide the best images yet taken of many huge glowing star formation regions, such as the one pictured here.

Zooming in on the Prawn Nebula

The very sharp VST images were further enhanced to bring out the colour by including additional high quality imaging through other filters taken by Martin Pugh, a very skilled amateur astronomer observing from Australia using 32-centimetre and 13-centimetre telescopes [3].

A close-up look at the Prawn Nebula from ESO’s VST

This press release represents a milestone — it is the 1000th press release issued by ESO. The first one appeared in late 1985 and featured a picture of Halley's Comet. They are all available online.


[1] This is the same kind of radiation that causes unprotected human skin to burn when exposed to too much direct sunlight. But the Earth’s atmosphere shields life on the surface from most ultraviolet radiation and only longer wavelengths (between about 300 and 400 nanometres) reach the ground and cause tanning and burning of human skin. Some of the ultraviolet radiation emitted by very hot stars in HII regions is at the much shorter wavelengths (shorter than 91.2 nanometres) that can ionise hydrogen.

[2] Astronomers use the term “HII” (pronounced “aitch-two”) to refer to ionised hydrogen, and “HI” (aitch-one) for atomic hydrogen. A hydrogen atom consists of an electron bound to a proton; in an ionised gas, atoms are split into freely-moving electrons and positive ions — in this case the positive ions are just single protons.

[3] More details of his observations can be found at Martin Pugh’s information page on this object.

More information:

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. 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 the 39-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.


The VPHAS+ survey:

Photos of the VST:

Photos taken with the VST:

Images, Text, Credits: ESO. Acknowledgement: Martin Pugh / IAU and Sky and Telescope/Videos: ESO/Nick Risinger ( Martin Pugh / Music: movetwo.


NASA Partner Orbital Sciences Launches Demonstration Mission to Space Station

Orbital - Antares A-One Mission patch

Sept 19, 2013

 Antares Rocket With Cygnus Spacecraft Launches From Wallops Flight Facility

September 18 2013, NASA commercial space partner Orbital Sciences Corporation of Dulles, Va., successfully launched its Cygnus cargo spacecraft aboard its Antares rocket at 10:58 a.m. EDT Wednesday from the Mid-Atlantic Regional Spaceport Pad-0A at NASA’s Wallops Flight Facility in Virginia.

Antares Rocket Lifts Off

This is the first time a spacecraft launched from Virginia is blazing a trail toward the International Space Station, heralding a new U.S. capability to resupply the orbiting laboratory.

Antares Rocket With Cygnus Spacecraft Launches

Traveling 17,500 mph in Earth's orbit, Cygnus is on its way to rendezvous with the space station Sunday, Sept. 22. The spacecraft will deliver about 1,300 pounds (589 kilograms) of cargo, including food and clothing, to the Expedition 37 crew, who will grapple and attach the capsule using the station's robotic arm.

"Today marks a milestone in our new era of exploration as we expand the capability for making cargo launches to the International Space Station from American shores," said NASA Administrator Charles Bolden. "Orbital's extraordinary efforts are helping us fulfill the promise of American innovation to maintain our nation's leadership in space."

Orbital is building and testing its Antares rocket and Cygnus spacecraft under NASA’s Commercial Orbital Transportation Services (COTS) Program. The successful completion of the COTS demonstration mission will pave the way for Orbital to conduct eight planned cargo resupply flights to the space station through NASA’s $1.9 billion Commercial Resupply Services contract with the company.

Cygnus is on its way to rendezvous with the space station

Future Cygnus flights will significantly increase NASA's ability to deliver new science investigations to the only laboratory in microgravity. As one of two U.S. carriers capable of providing cargo resupply missions to the space station, a successful demonstration mission will ensure a robust national capability to deliver critical science payloads to orbit. NASA's other cargo resupply provider, Space Exploration Technologies (SpaceX), began flying regular cargo missions to the space station in 2012, following its own COTS demonstration mission.

"Today’s launch is the culmination of more than five years’ work between the NASA and Orbital teams," said Alan Lindenmoyer, NASA’s program manager for commercial crew and cargo. "Everyone involved should be extremely proud, and we are looking forward to a successful series of checkouts between now and when Cygnus reaches the space station this weekend."

Over the next several days, Cygnus will perform a series of maneuvers to test and prove its systems, ensuring it can safely enter the so-called "keep-out sphere" of the space station, a 656-foot (200-meter) radius surrounding the complex.

NASA Television coverage for grapple and berthing operations will begin at 4:30 a.m.  Sept. 22 and continue through the capture and installation of the Cygnus spacecraft. Capture is scheduled for about 7:25 a.m. with installation of the spacecraft beginning around 9 a.m.

A joint news conference will take place at NASA's Johnson Space Center in Houston and at Orbital's Headquarters at 45101 Warp Drive, in Dulles, Va., at about 1 p.m. EDT, after Cygnus operations are complete. The briefing will be carried live on NASA TV and the agency's website. Media may participate by telephone by calling the Johnson newsroom at 218-483-5111 no later than 15 minutes prior to the start of the briefing. Media interested in attending the briefing in Houston should contact Johnson's newsroom no later than 5 p.m. EDT Friday, Sept. 20. Media with U.S. citizenship who want to attend the briefing at Orbital should contact Barron Beneski at 703-406-5528 or by noon Friday, Sept. 20. The registration deadline for non-U.S. citizens has passed.

Cygnus description

NASA initiatives such as COTS are helping to develop a robust U.S. commercial space transportation industry with the goal of achieving safe, reliable and cost-effective transportation to and from the International Space Station and low-Earth orbit. NASA’s Commercial Crew Program also is working with commercial space partners to develop capabilities to launch U.S. astronauts from American soil in the next few years.

The International Space Station is a convergence of science, technology and human innovation that demonstrates new technologies and makes research breakthroughs not possible on Earth. The space station has had continuous human occupation since November 2000. In that time it has been visited by more than 200 people and a variety of international and commercial spacecraft. The space station remains the springboard to NASA's next great leap in exploration, including future missions to an asteroid and Mars.

For more information about the Orbital demonstration mission, visit:

For more information about the International Space Station, visit:

Images, Video, Text, Credits: NASA / Bill Ingalls.

Best regards,

lundi 16 septembre 2013


ESA / NASA - SOHO Mission patch.

16 September 2013

 A fiery solar explosion

Like a dragon breathing fire, a powerful blast of plasma erupts from the Sun in this colourised view of a ‘coronal mass ejection’.

These huge clouds of magnetised plasma are ejected from the Sun’s atmosphere – the corona – and launched into interplanetary space. Millions of tonnes of gas race away from the Sun at several million kilometres per hour.

This image shows an event observed by the SOHO satellite on 4 January 2002, coloured to indicate the intensity of the matter being ejected by the Sun. White represents the greatest intensity, red/orange somewhat less, and blue the least.

An extreme-ultraviolet view is superimposed to show the size and active regions of the Sun that day.

SOHO sees eruptive prominence (16/03/2004 10:25 am)

The shaded blue disc surrounding the Sun at the centre of the image deliberately blots out direct sunlight to allow study of the details in the corona.

When ejections like this hit planet Earth, spectacular natural light displays – aurora – can be triggered over the poles. In the most extreme events, they can lead to geomagnetic storms that can result in regional power outages and communications blackouts.

SOHO spacecraft

This image is featured in a SOHO ‘The Sun as Art’ portfolio in 2002. The original SOHO image can be viewed here:

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Images, Text, credits: SOHO (ESA / NASA) / S. Hill.