vendredi 23 décembre 2011

Festival of Lights

NASA - Wide-field Infrared Survey Explorer (WISE) patch.

Dec. 23, 2011

WISE, NASA's Wide-field Infrared Survey Explorer, has a new view of Barnard 3, or IRAS Ring G159.6-18.5, that is awash in bright green and red dust clouds. Interstellar clouds like these are stellar nurseries, where baby stars are being born.

The green ring is made of tiny particles of warm dust whose composition is very similar to smog found here on Earth. The red cloud in the center is most likely made of dust that is more metallic and cooler than the surrounding regions. HD 278942, the bright star in the middle of the red cloud, is so luminous that it is the likely cause of the surrounding ring's glow. The bright greenish-yellow region left of center is similar to the ring, though more dense. The bluish-white stars scattered throughout are stars located both in front of, and behind, the nebula.

Wide-field Infrared Survey Explorer (WISE)

Regions similar to this nebula are found near the band of the Milky Way galaxy in the night sky. This nebulas is slightly off this band, near the boundary between the constellations of Perseus and Taurus, but at a relatively close distance of only about 1,000 light-years, the cloud is a still part of our Milky Way.

The colors used in this image represent specific wavelengths of infrared light. Blue and cyan (blue-green) represent light emitted at wavelengths of 3.4 and 4.6 microns, which is predominantly from stars. Green and red represent light from 12 and 22 microns, respectively, which is mostly emitted by dust.

For more information about WISE, visit:

Images, Text, Credit: NASA / JPL-Caltech / UCLA.


Cosmonaut and Astronaut's arrives at the Space Station


ROSCOSMOS - Soyuz TMA-03M Mission patch / ESA - PromISSe Mission patch.

23 December 2011

ESA astronaut André Kuipers and crewmates Oleg Kononeko and Don Pettit docked today with the International Space Station in their Soyuz TMA-03M spacecraft. They will work aboard the Station now for five months and return to Earth in May.

ESA’s fourth long mission on the International Space Station began on Wednesday, when the Soyuz rocket roared into the evening sky from Baikonur Cosmodrome in Kazakhstan.

Approaching the Space Station

After circling the globe for the last two days, the spacecraft docked at 13:43 GMT (14:43 CET) this evening, 23 December.

The automated rendezvous sequence began about two hours before docking, but the crew, led by commander Oleg Kononenko, were ready to take over manually if required.

A routine arrival

Preparing for arrival, the crew closed the hatch between the two Soyuz modules, donned their Sokol pressure suits and carefully monitored the approach and docking sequence.

View to the Soyuz spacecraft after the launch

Soyuz slowly flew around the Station and spiralled in to perfect alignment with the Earth-facing docking port of Russia’s Zarya module.

With TV cameras transmitting views of the Station, Soyuz fired its small thrusters for the final approach.

After docking, a firm connection is being confirmed and, when pressure checks found no air leaks, the crew will remove their suits. The hatch to the Station will be opened after the pressure is equalised between the two vehicles.

Mission full of PromISSe

During his mission, PromISSe, André will conduct more than 25 ESA experiments and around 20 for NASA and Japan’s space agency, JAXA, including human research, biology, fluid physics, materials science, radiation research and technology.

Soyuz liftoff on Wednesday

His mission also features a strong educational aspect centred on the theme ‘Spaceship Earth’.

The lessons from space will educate children in science, technology, engineering and mathematics, as well as illustrating the requirements for life on Earth.

As part of ‘Mission-X: Train Like an Astronaut’, André will invite thousands of students to perform physical exercises and classroom lessons to compete with teams around the world to become as fit as astronauts.

Greeting audience at the launch pad

Following his mission is easy: André is tweeting on @astro_andre and writing his own mission diary in Dutch (‘Logboek’) with English translations.

The PromISSe blog covers the whole mission and it’s also an ideal way to post questions and comments.

For more information about the mission, take a look at

Related links:


Mission diary in Dutch:

English translations:

PromISSe blog:

ISS Expedition 30 (NASA):

ISS Expedition 31 (NASA):

Roscosmos (Russia):

Ruimteschip Aarde:

Images, Video, Text, Credits: ESA, S. Corvaja / ROSCOSMOS / ROSCOSMOS TV / NASA TV / Youtube.


jeudi 22 décembre 2011

NASA's Cassini Delivers Holiday Treats From Saturn

NASA - Cassini Mission to Saturn patch.

Dec. 22, 2011

Image above: Saturn's third-largest moon Dione can be seen through the haze of its largest moon, Titan, in this view of the two posing before the planet and its rings from NASA's Cassini spacecraft. Image credit: NASA / JPL-Caltech / Space Science Institute.

No team of reindeer, but radio signals flying clear across the solar system from NASA's Cassini spacecraft have delivered a holiday package of glorious images. The pictures, from Cassini's imaging team, show Saturn's largest, most colorful ornament, Titan, and other icy baubles in orbit around this splendid planet. The release includes images of satellite conjunctions in which one moon passes in front of or behind another. Cassini scientists regularly make these observations to study the ever-changing orbits of the planet's moons. But even in these routine images, the Saturnian system shines. A few of Saturn's stark, airless, icy moons appear to dangle next to the orange orb of Titan, the only moon in the solar system with a substantial atmosphere. Titan's atmosphere is of great interest because of its similarities to the atmosphere believed to exist long ago on the early Earth.

The images are online at:, and .

Image above: The colorful globe of Saturn's largest moon, Titan, passes in front of the planet and its rings in this true color snapshot from NASA's Cassini spacecraft. Image credit: NASA / JPL-Caltech / Space Science Institute.

While it may be wintry in Earth's northern hemisphere, it is currently northern spring in the Saturnian system and it will remain so for several Earth years. Current plans to extend the Cassini mission through 2017 will supply a continued bounty of scientifically rewarding and majestic views of Saturn and its moons and rings, as spectators are treated to the passage of northern spring and the arrival of summer in May 2017.

"As another year traveling this magnificent sector of our solar system draws to a close, all of us on Cassini wish all of you a very happy and peaceful holiday season, " said Carolyn Porco, Cassini imaging team lead at the Space Science Institute, Boulder, Colo.

Image above: Saturn's moon Tethys, with its stark white icy surface, peeps out from behind the larger, hazy, colorful Titan in this Cassini view of the two moons. Image credit: NASA / JPL-Caltech / Space Science Institute.

More information about Cassini mission is online at and .

Cassini spacecraft. Credit: NASA / JPL

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute in Boulder, Colo.

Images (mentioned), Text, Credits: NASA / JPL / Jia-Rui Cook / Space Science Institute / Joe Mason.

Best regards,

NASA Telescopes Help Find Rare Galaxy at Dawn of Time

NASA - SPITZER Space Telescope patch / NASA & ESA - Hubble Space Telescope patch.

Dec. 22, 2011

This image shows one of the most distant galaxies known, called GN-108036, dating back to 750 million years after the Big Bang that created our universe. Image credit: NASA / JPL-Caltech / STScI / University of Tokyo.

Astronomers using NASA's Spitzer and Hubble space telescopes have discovered that one of the most distant galaxies known is churning out stars at a shockingly high rate. The blob-shaped galaxy, called GN-108036, is the brightest galaxy found to date at such great distances.

The galaxy, which was discovered and confirmed using ground-based telescopes, is 12.9 billion light-years away. Data from Spitzer and Hubble were used to measure the galaxy's high star production rate, equivalent to about 100 suns per year. For reference, our Milky Way galaxy is about five times larger and 100 times more massive than GN-108036, but makes roughly 30 times fewer stars per year.

"The discovery is surprising because previous surveys had not found galaxies this bright so early in the history of the universe," said Mark Dickinson of the National Optical Astronomy Observatory in Tucson, Ariz. "Perhaps those surveys were just too small to find galaxies like GN-108036. It may be a special, rare object that we just happened to catch during an extreme burst of star formation."

The international team of astronomers, led by Masami Ouchi of the University of Tokyo, Japan, first identified the remote galaxy after scanning a large patch of sky with the Subaru Telescope atop Mauna Kea in Hawaii. Its great distance was then carefully confirmed with the W.M. Keck Observatory, also on Mauna Kea.

 SPITZER Space Telescope. Credit: NASA.

"We checked our results on three different occasions over two years, and each time confirmed the previous measurement," said Yoshiaki Ono of the University of Tokyo, lead author of a new paper reporting the findings in the Astrophysical Journal.

GN-108036 lies near the very beginning of time itself, a mere 750 million years after our universe was created 13.7 billion years ago in an explosive "Big Bang." Its light has taken 12.9 billion years to reach us, so we are seeing it as it existed in the very distant past.

Astronomers refer to the object's distance by a number called its "redshift," which relates to how much its light has stretched to longer, redder wavelengths due to the expansion of the universe. Objects with larger redshifts are farther away and are seen further back in time. GN-108036 has a redshift of 7.2. Only a handful of galaxies have confirmed redshifts greater than 7, and only two of these have been reported to be more distant than GN-108036.

 Hubble Space Telescope. Credit: NASA / ESA

Infrared observations from Spitzer and Hubble were crucial for measuring the galaxy's star-formation activity. Astronomers were surprised to see such a large burst of star formation because the galaxy is so small and from such an early cosmic era. Back when galaxies were first forming, in the first few hundreds of millions of years after the Big Bang, they were much smaller than they are today, having yet to bulk up in mass.

During this epoch, as the universe expanded and cooled after its explosive start, hydrogen atoms permeating the cosmos formed a thick fog that was opaque to ultraviolet light. This period, before the first stars and galaxies had formed and illuminated the universe, is referred to as the "dark ages." The era came to an end when light from the earliest galaxies burned through, or "ionized," the opaque gas, causing it to become transparent. Galaxies similar to GN-108036 may have played an important role in this event.

"The high rate of star formation found for GN-108036 implies that it was rapidly building up its mass some 750 million years after the Big Bang, when the universe was only about five percent of its present age," said Bahram Mobasher, a team member from the University of California, Riverside. "This was therefore a likely ancestor of massive and evolved galaxies seen today."

Other authors include: Kyle Penner and Benjamin J. Weiner of the University of Arizona, Tucson; Kazuhiro Shimasaku and Kimihiko Nakajima of the University of Tokyo; Jeyhan S. Kartaltepe of the National Optical Astronomy Observatory; Hooshang Nayyeri of the University of California, Riverside; Daniel Stern of NASA's Jet Propulsion Laboratory, Pasadena, Calif.; Nobunari Kashikawa of the National Astronomical Observatory of Japan; and Hyron Spinrad of University of California, Berkeley.

NASA / ESA Hubble Space Telescope. JPL manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. For more information about Spitzer, visit and .

Images (mentioned), Text, Credit: NASA / ESA / JPL / Whitney Clavin.


CryoSat ice satellite rides new waves

ESA - CRYOSAT 2 Mission logo.

22 December 2011

ESA’s CryoSat mission has been gathering detailed information on the thickness of Earth’s ice since its launch in 2010. Through international collaboration, this state-of-the-art mission is soon to be used to monitor conditions at sea for marine forecasting.

CryoSat was built to measure tiny variations in the thickness of Earth’s ice. As a result, the mission is providing scientists with the data they need to help improve our understanding of the relationship between ice, climate and sea level.

Wind speed from CryoSat

As CryoSat orbits from pole to pole, it passes over vast expanses of ocean. So while the mission was designed specifically for ice monitoring, it can also serve to help improve the safety of marine traffic. 

The satellite carries Europe’s first radar altimeter specialised for the purpose of detecting tiny variations in the height of the ice – but it can also be used to measure sea level and the height of the waves.

The instrument sends out short radar pulses and measures the time it takes for the signals to travel from the satellite to the ground and back. This information provides the height of the surface below.

CryoSat in orbit

The advantage of yielding this kind of information from CryoSat is also down to the advanced performance of its main SIRAL instrument.

When data from CryoSat are merged with other altimeter data such as that from the Envisat and Jason satellites, the combined estimation of wave height and wind speed is greatly improved.

In addition, thanks to its drifting orbit, CryoSat allows a high number of crossovers with other altimeter missions. This provides a set of measurements that have not been available before.

Marine weather forecasts are essential for the safe passage of vessels but accurate forecasts need a supply of timely wind and wave observations.

Since CryoSat’s primary objective was measure ice, fast data delivery was not initially intended.

Wave height from CryoSat

However, the CryoSat team has changed this to demonstrate that CryoSat can deliver marine information in near-real time from most of its orbits around Earth.

Up to now, this new product called 'fast delivery mode' has only been provided to organisations such the National Ocean and Atmospheric Organisation (NOAA) in the US.

This is about to change: marine information is expected to be available systematically to all users from February.

At NOAA’s Laboratory for Satellite Altimetry (LSA), the CryoSat data are processed to estimate wind speed and wave height, which are then provided to forecasters at NOAA’s National Centres for Environmental Predication.

CryoSat is also providing data on sea level. This is important for monitoring the movement of the ocean waters and mapping the heat content of the upper layers – a reservoir of energy that can lead to tropical storms and hurricanes.

Sea level from CryoSat and other satellites

LSA combines CryoSat data with information from other organisations such as the French space agency CNES, the European Centre for Medium-Range Weather Forecasts and NASA.

This processing takes a matter of only three days. NOAA delivers these data to ocean modellers and forecasters worldwide.

For example, Australia’s Integrated Marine Observing System now uses CryoSat observations of sea level to monitor surface currents.

This is not only a prime example of what an international approach can achieve in Earth observation, but also demonstrates that although ESA’s family of Earth Explorer satellites are designed with a specific scientific objective in mind, they are able to offer so much more – benefiting both science and the way we live.

Related links:


Access CryoSat data:

In depth, CryoSat-2:


CSIRO Marine and Atmospheric Research:

IMOS Integrated Marine Observing System:

Images, Video, Text, Credits: Credits: ESA / AOES Medialab / NOAA, E. Leuliette, J. Sienkiewicz / CSIRO, D. Griffen.

Best regards,

First Galileo satellite producing full spectrum of signals

ESA - GALILEO / GIOVE Mission logo.

22 December 2011

Europe’s first Galileo satellite appears in blooming health, transmitting test signals received by ESA’s ground station in Redu, Belgium across the whole of its assigned radio spectrum.

The first two Galileo satellites were launched by Soyuz from Europe’s Spaceport in French Guiana on 21 October. They are currently in the midst of a rigorous campaign to check that their highly sophisticated navigation payloads are operating as planned, unaffected by the strains of launch.

Galileo team at Redu receiving signals

Testing is centred on the first Galileo satellite for now, expected to progress to the second satellite early in the new year.

Galileo is a state-of-the-art global satellite navigation system offering various groups of users a total of ten different modulated signals across three spectral bands, known as E1, E5 and E6. 

Last weekend all Galileo signals were activated simultaneously across these bands for the first time, following the switch-on and ‘outgassing’ – warming up to vent potentially harmful vapours – of power amplifiers in the remaining E6 band.

First Galileo triple band signals

The signals were received by Galileo Test User Receivers deployed at the Redu ground station, within Belgium’s Ardennes forest, as well as by identical receivers at ESA’s Navigation Laboratory, in ESA’s ESTEC technical centre in Noordwijk, the Netherlands.

These test receivers work in the same way as operational receivers will once Galileo begins its initial services in 2014. They are capable of processing the Open Service, Commercial Service and Safety-of-Life Service signals from the Galileo constellation.

First two Galileo IOV satellites

Galileo combines multi-frequency signals with the most accurate atomic clock ever flown in space for navigation, accurate to one second in three million years. Its signals should open up a large number of commercial applications by combining this accuracy with the increased reliability of dual- or triple-frequency measurements.

Receiver developers can choose among the variety of Galileo signals on offer to meet the needs of their customers in the most efficient way. They can even combine the processing of Galileo signals with US GPS or Russian Glonass signals to offer more robust positioning information in challenging environments such as city centre ‘urban canyons’.

Related Links:

Soyuz-Galileo IOV launch website:



Redu Centre:

Images, Text, Credits: ESA / P. Carril.


Proba-2 tracks Comet Lovejoy through Sun’s fiery corona

ESA - PROBA-2 Mission logo.

22 December 2011

 Comet Lovejoy's passage round the Sun

ESA’s Proba-2 micro-satellite joined a flotilla of spacecraft observing deep-frozen Comet Lovejoy’s plunge through the million degree corona enshrouding the Sun, providing a close-up extreme ultraviolet view of the comet passing just 120 000 km from the Sun’s surface – and then, surprisingly, surviving.

Lovejoy had not been predicted to endure its swing by the Sun, but is now headed back out to the colder outer reaches of the Solar System, and should be visible from Earth’s northern hemisphere in mid-January.

Proba-2’s SWAP imager took part in a coordinated effort to track Comet Lovejoy as it came closest to the Sun on 16 December, working along with the ESA/NASA SOHO solar watchdog, Japan’s Hinode mission, NASA’s twin STEREO spacecraft and its Solar Dynamics Observatory.

SWAP showed the comet as a bright streak in the solar corona, with interactions between the comet tail causing brief coronal brightening and wiggles in the comet’s tale. This was only the second time ever that a comet has been observed through an extreme-ultraviolet (EUV) solar telescope. The instrument’s observations – interrupted briefly as Proba-2 crossed behind Earth – show the comet going behind the Sun and then emerging back into view from the other side.

Comet Lovejoy seen by SOHO

Comets are drawn to the gravitational pull of the Sun like moths to a flame – SOHO has identified thousands of Sun-grazing comets over the last 16 years. But up until now, what happens when a comet draws closest to the Sun has been a mystery.

Comets in the Sun’s neighbourhood usually seen with ‘coronagraph’ telescopes that block out the bright solar disc to observe the faint solar corona they are tuned for. This makes detailed images of comets nearing the Sun very hard to obtain.

It turns out however that EUV imagers that detect the extreme ultraviolet corona from the solar disk can also show the comet. Since the dust and other material making up a comet’s tail do not radiate at EUV wavelengths, this came as a surprise.


As comets are so dim compared to the radiance of the Sun and its corona, the Proba-2 team made a careful calculation of the comet’s path to know where to look, and performed careful processing to make the comet stand out from the bright coronal plasma.

A comet’s tail is formed by the outgoing solar wind, leading it to always point away from the Sun. The Proba-2 images show this tail wobbling, possibly due to localised gusts of solar wind blowing the tail at different speeds near the Sun.

About Comet Lovejoy

Comet Lovejoy is one of a family of comets called Kreutz sun-grazer comets. These are all part of a cloud of debris left over from one large comet that previously broke apart. These comets share an elliptical orbit around the Sun, part of which takes them close enough that many smaller comets don’t survive (unlike Comet Lovejoy).

About Proba-2’s SWAP

Proba-2 is a technology demonstration mission that also hosts scientific instruments, including the Sun Watcher with Active Pixels and Image Processing, SWAP, operated by the Royal Observatory of Belgium. SWAP observes the solar corona, whose outer layers are almost invisible to the naked eye because they radiate in ultraviolet and EUV. SWAP converts EUV to a visible picture, acquiring a new image around once per minute.

Related links:

ROB Proba-2 science centre:


SOHO overview:

Images, Video, Text, Credits: ESA /Pierre Carril / ROB / SOHO / LASCO (ESA/NASA).


Dawn Obtains First Low Altitude Images of Vesta

NASA - Dawn Mission patch.

Dec. 22, 2011

Images above: NASA's Dawn spacecraft has spiraled closer and closer to the surface of the giant asteroid Vesta. Image credit: NASA / JPL-Caltech / UCLA / MPS / DLR / IDA.

NASA's Dawn spacecraft has sent back the first images of the giant asteroid Vesta from its low-altitude mapping orbit. The images, obtained by the framing camera, show the stippled and lumpy surface in detail never seen before, piquing the curiosity of scientists who are studying Vesta for clues about the solar system's early history.

At this detailed resolution, the surface shows abundant small craters, and textures such as small grooves and lineaments that are reminiscent of the structures seen in low-resolution data from the higher-altitude orbits. Also, this fine scale highlights small outcrops of bright and dark material.

This image, one of the first obtained by NASA's Dawn spacecraft in its low altitude mapping orbit, shows an area within the Rheasilvia basin in the south polar area of the giant asteroid Vesta. Image credit: NASA / JPL-Caltech / UCLA / MPS / DLR / IDA.

A gallery of images can be found online at:

The images were returned to Earth on Dec. 13. Dawn scientists plan to acquire data in the low-altitude mapping orbit for at least 10 weeks. The primary science objectives in this orbit are to learn about the elemental composition of Vesta's surface with the gamma ray and neutron detector and to probe the interior structure of the asteroid by measuring the gravity field.

This image, one of the first obtained by NASA's Dawn spacecraft in its low altitude mapping orbit, shows a part of one of the troughs at the equator of the giant asteroid Vesta. Image credit: NASA / JPL-Caltech/ UCLA / MPS / DLR / IDA.

The Dawn mission to the asteroids Vesta and Ceres is managed by NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, for NASA's Science Mission Directorate, Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Ala. UCLA is responsible for overall Dawn mission science. The Dawn Framing Cameras have been developed and built under the leadership of the Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany, with significant contributions by DLR German Aerospace Center, Institute of Planetary Research, Berlin, and in coordination with the Institute of Computer and Communication Network Engineering, Braunschweig. The framing camera project is funded by the Max Planck Society, DLR, and NASA / JPL.

More information about the Dawn mission is online at: and

Images (mentioned), Text, Credit: NASA / JPL / Jia-Rui Cook.


mercredi 21 décembre 2011

NASA Conducts Orion Parachute Testing For Orbital Test Flight

NASA - MPCV Orion logo.

Dec. 21, 2011

NASA successfully conducted a drop test of the Orion crew vehicle's parachutes high above the Arizona desert Tuesday in preparation for its orbital flight test in 2014. Orion will carry astronauts deeper into space than ever before, provide emergency abort capability, sustain the crew during space travel and ensure a safe re-entry and landing.

A C-130 plane dropped the Orion test article from an altitude of 25,000 feet above the U.S. Army's Yuma Proving Grounds. Orion's drogue chutes were deployed between 15,000 and 20,000 feet, followed by the pilot parachutes, which then deployed two main landing parachutes. This particular drop test examined how Orion would land under two possible failure scenarios.

Orion's parachutes are designed to open in stages, which is called reefing, to manage the stresses on the parachutes after they are deployed. The reefing stages allow the parachutes to sequentially open, first at 54 percent of the parachutes' full diameter, and then at 73 percent. This test examined how the parachutes would perform if the second part of the sequence was skipped.

The second scenario was a failure to deploy one of Orion's three main parachutes, requiring the spacecraft to land with only two. Orion landed on the desert floor at a speed of almost 33 feet per second, which is the maximum designed touchdown speed of the spacecraft.

Since 2007, the Orion program has conducted a vigorous parachute air and ground test program and provided the chutes for NASA's successful pad abort test in 2010. Lessons learned from this experience have improved Orion's parachute system.

For images of the drop test, visit:

For more about Orion, visit:

Images, Text, Credit: NASA.


INTEGRAL deciphers diffuse signature of cosmic-ray electrons

ESA - INTEGRAL Mission patch.

21 Dec 2011

Astronomers exploiting six years worth of data from ESA's INTEGRAL mission have pinned down the individual processes contributing to the high-energy Galactic interstellar emission produced by cosmic-ray electrons. Deciphering each of the different physical mechanisms at play at hard X-ray and soft gamma-ray wavelengths represents a crucial step towards an increasingly detailed picture of the population of high-energy particles permeating the Milky Way.

Cosmic rays are highly-energetic charged particles that pervade galaxies, including our own Galaxy, the Milky Way, and can also escape from them and travel across intergalactic space. They are important players in regulating global galactic properties such as the heating balance and the total energy budget, and have been subject to intense investigation ever since their discovery in 1912.

The hard X-ray sky as seen with INTEGRAL / SPI. Credits: ESA / INTEGRAL / SPI

Researchers study these particles either directly, by detecting the tracks that arise from collisions with material in the Earth's atmosphere, or indirectly, by tracing the radiation emitted when cosmic rays interact with different components of a galaxy – for example, other particles, photons, magnetic fields. In the Milky Way, these phenomena are among the primary sources of the distinctive 'diffuse' emission that is seen along the Galactic Plane, at both the low energy (radio, microwave) and high energy (hard X-ray, gamma ray) ends of the electromagnetic spectrum.

This 'glow' is due to a combination of many different processes. Extensive observations across many wavelengths, as well as detailed physical modelling, are required to disentangle all contributions and to help solve the puzzle of the charged particles that fill our Galaxy.

"The diffuse emission at hard X-ray and soft gamma-ray wavelengths is an excellent tracer of cosmic-ray electrons and their antiparticles, the positrons, a minor but very significant fraction of the high-energy particle population in the Milky Way," explains Laurent Bouchet from Université de Toulouse and Institut de Recherche en Astrophysique et Planétologie (IRAP) in France. Bouchet and his international team exploited data from ESA's INTEGRAL mission, probing the entire sky at energies between 20 keV and 2.4 MeV. Exploring the diffuse emission in this energy range is one of the main science goals of the INTEGRAL mission, and after almost a decade of operation the mission has finally achieved the unprecedented sensitivity required to push this inquiry to the next level.

The study conducted by Bouchet and his collaborators relies on data collected with the Spectrometer on board INTEGRAL (SPI) over a time span of six years. "Such a long exposure allowed us to isolate, with very high precision, the different physical processes that account for the total emission in the spectral window probed by INTEGRAL," he adds.

The first step in the complex analysis performed by the team consists of a careful scrutiny of the data to remove all point sources, both galactic and extragalactic, that radiate at these wavelengths. In this context, point sources represent a contamination of the diffuse signal produced by cosmic rays. "We have identified a few hundred sources across the entire sky and established that their contribution is dominant at the lowest energies examined in this work, between 20 and 100 keV," notes Bouchet. After point-source removal, the observed diffuse emission was compared with model predictions, in order to break it down into the individual physical processes that contribute to it.

Graphic above: Different contributions to the total emission at hard X-ray and soft gamma-ray energies, as measured with INTEGRAL/SPI. Courtesy of L. Bouchet (Univ. Toulouse and IRAP).

"Interestingly, we found a major contribution due to Inverse Compton (IC) scattering, thus confirming what early INTEGRAL data had hinted at a few years ago," comments Andrew Strong from the Max-Planck Institut für Extraterrestrische Physik (MPE) in Germany. IC scattering consists of collisions between highly energetic electrons (or positrons) and low-energy photons present in interstellar space, which result in the electrons transferring part of their energy to the photons, thus 'boosting' them to X- and gamma-ray wavelengths. Cosmic-ray electrons interact via IC scattering with infrared and visible photons emitted by stars, and with the ubiquitous photons of the cosmic microwave background radiation.

The team made use of a very detailed model of the interstellar radiation field in the inner part of the Galaxy, a crucial ingredient to be taken into account in order to achieve a thorough physical interpretation of the observed emission. "Together with the latest models and improved data analysis techniques, the new INTEGRAL data allowed us to unequivocally identify IC scattering as the principal mechanism producing diffuse emission between 100 and 200 keV, as well as between 600 keV and 2 MeV," adds Strong.

Besides the clear feature of IC scattering, the data also exhibit the well studied signatures of other emission processes arising in this spectral band – the annihilation of positrons with electrons and the radioactive decay of some unstable atomic nuclei. When positrons and electrons collide, two things may happen: they may destroy each other immediately, releasing a pair of photons each with an energy of 511 keV; alternatively, they may create an unstable and short-lived two-particle system called positronium, which soon decays into two or more photons, producing a distinctive continuum emission spectrum up to 511 keV. At energies above 1 MeV, the data also exhibit characteristic decay features of two unstable isotopes of aluminium (26Al) and iron (60Fe). This indicates the presence of these radioactive nuclei - the products of recent nucleosynthesis in supernova explosions - throughout the diffuse interstellar medium of the Milky Way.

"In addition to these mechanisms, the data require a further component to be taken into account at low energies, below 50 keV," notes Bouchet. "This is most likely due to the superposition of many unresolved faint sources, as pointed out by previous studies based on data from the IBIS imager on board INTEGRAL," he adds. Stars with very hot coronae and cataclysmic variable stars are the main objects contributing to this unresolved emission.

Artist's impression of Integral. Credit: ESA

The study of Bouchet and collaborators enabled models of cosmic ray propagation to be tested in this portion of the electromagnetic spectrum in greater detail than previously possible. "The data demonstrate that our current understanding of the properties of cosmic-ray electrons in the Milky Way is qualitatively correct," notes Strong. As INTEGRAL keeps scanning the high-energy sky, even longer exposures will be available in the future. "With more data and improved analysis methodology, we plan to explore quantitatively the distribution of cosmic-ray electrons across the Galaxy, narrowing down important parameters such as the size of the Galactic region within which the particles are confined," he adds.

Ultimately, it is essential to verify that the data fit well within the physical scenario suggested by other observations. In particular, there is a consensus on the general picture provided by both INTEGRAL and the Large Area Telescope (LAT) on board NASA's Fermi Gamma-ray Space Telescope. Sensitive to gamma rays between 20 MeV and 300 GeV, Fermi-LAT observes the sky at higher energies than INTEGRAL, and the agreement reached by these two complementary missions is very encouraging.

"This long-awaited result showcases INTEGRAL's uniqueness in probing such a crucial spectral window," comments Chris Winkler, INTEGRAL Project Scientist at ESA. "The large amount of data accumulated by INTEGRAL is now revealing the mission's full potential for exciting results and discoveries."

Notes for editors:

The study presented here is based on observations performed with the Spectrometer on board INTEGRAL (SPI) between 22 February 2003 and 2 January 2009. The data probe the entire sky at energies between 20 keV and 2.4 MeV.

The data were compared to model predictions obtained with GALPROP, a publicly available code for calculating the propagation of cosmic-ray nuclei, antiprotons, electrons and positrons. The code also computes diffuse gamma-ray and synchrotron emission resulting from the cosmic rays. The first version of GALPROP was developed in the mid-1990s by Andrew W. Strong (MPE, Germany) and Igor V. Moskalenko (Stanford University, USA), both co-authors of the paper presented here. The code is currently maintained by a small team of researchers. In particular, GALPROP includes the most advanced model presently available of the interstellar radiation in the inner Galaxy, which has been developed by Troy A. Porter (Stanford University, USA), who is also a co-author of the paper presented here.

INTEGRAL is an ESA project with instruments and science data centre funded by ESA Member States (especially the Principal Investigator countries: Denmark, France, Germany, Italy, Spain, Switzerland) and Poland, and with the participation of Russia and the USA.

Related publications:

L. Bouchet, et al., "Diffuse Emission Measurement with the SPectrometer on Integral as an Indirect Probe of Cosmic-ray Electrons and Positrons", 2011, The Astrophysical Journal, 739, 29.

For more information about INTEGRAL, visit:

Images (mentioned), Text, Credits: Université de Toulouse and Institut de Recherche en Astrophysique et Planétologie (IRAP), Laurent Bouchet / Max-Planck Institut für Extraterrestrische Physik (MPE), Andrew W. Strong / INTEGRAL Project Scientist Research and Scientific Support Department Directorate of Science and Robotic Exploration ESA, Chris Winkler.

Best regards,

Launch of manned spacecraft Soyuz TMA-03M

ROSCOSMOS - Soyuz TMA-03M Mission patch.


 Soyuz TMA-03M on a launch pad

December 21 at 17.16.15 GMT on a launch pad site Baikonur was put space rocket (ILV) Soyuz-FG with transport manned spacecraft (TLC) Soyuz TMA-03M (Commander Oleg Kononenko (Roscosmos), flight engineers Andre Kuipers (ESA) and Donald Pettit (NASA)).

Image above: The crew headed for the elevator, commander Oleg Kononenko, flight engineers, astronauts ship Andre Kuipers (ESA) and Donald Pettit (NASA) will take their places in the ship.

Soyuz TMA-03M Launch

After 528 seconds of flight rocket TPK Soyuz TMA-03M cleanly separated from the third stage to orbit an artificial satellite.

Soyuz TMA manned transport spacecraft cutaway

Docking of the Soyuz TMA-03M to the International Space Station is scheduled for December 23 this year at 19:22 Moscow time (10:22 a.m. EST on Friday).

Expedition 30 Commander Dan Burbank and Flight Engineers Anton Shkaplerov and Anatoly Ivanishin will welcome their new crewmates aboard the station a little while later when they open the hatches about 1 p.m.

Pettit, Kononenko and Kuipers are scheduled to live and work aboard the orbiting laboratory until May. They will become members of the Expedition 31 crew under the command of Kononenko when Burbank, Shkaplerov and Ivanishin undock in their Soyuz TMA-22 spacecraft in March.

Read more about Expedition 30:

Send a holiday postcard to the station crew:

More information about the International Space Station (ISS), visit:

Original text in Russian:

Images, Video, Text, Credits: Press Service of the Russian Space Agency (Roscosmos PAO) / Roscosmos TV / NASA / NASA TV / Translation:


mardi 20 décembre 2011

A Chinese Long March 3B rocket launch the Nigcomsat 1R satellite for Nigeria

CNSA - China National Space Administration logo.

Dec. 20, 2011

China launched a massive Nigerian communications satellite Monday to link Africans with television programming, education services and navigation signals.

Warning! This video has inaudible sound, turn off your speaker!
Long March 3B rocket launch the Nigcomsat 1R

Liftoff occurred at about 16:41 GMT (11:41 a.m. EST) Monday, or just after midnight Beijing time on Tuesday.

Manufactured by the China Academy of Space Technology, the Nigcomsat 1R satellite will replace a craft that lost power and failed in November 2008, less than 18 months after its launch on a Chinese rocket.

Long March 3B rocket launch

Nigcomsat Ltd., a company chartered by the Nigerian government, will operate the satellite for up to 15 years.

Nigcomsat 1R "will provide optimal and cost effective voice, data, video, Internet and application services solutions," the satellite's operator said.

 Logo of the satellite on the rocket fairing

An 18-story Long March 3B rocket will streak into space from the Xichang launch base in Sichuan province in southwestern China.

The three-stage rocket, boosted off the launch pad by four strap-on engines, will reach orbit 10 minutes into the mission. The rocket's hydrogen-fueled third stage will ignite a second time to place Nigcomsat 1R in an an oval-shaped transfer orbit with a low point of 124 miles, a high point of 26,092 miles and an inclination of 24.8 degrees, according to China Great Wall Industry Corp., the state-owned commercial sales firm for the Long March rocket family.

Separation of the 11,243-pound satellite is scheduled less than 26 minutes after liftoff. Nigcomsat 1R will ultimately be positioned in geosynchronous orbit over the equator at 42.5 degrees east longitude.

Nigcomsat 1R satellite

Nigcomsat 1R is based on China's DFH-4 spacecraft platform. China has reached agreements to build DFH-4 communications satellites for several non-traditional players in the space industry, including Pakistan, Nigeria, Venezuela, Laos and Bolivia.

Nigcomsat 1R's communications package includes 28 active transponders and seven antennas reaching across sub-Saharan Africa, Europe and Central Asia.

For more information about China National Space Administration (CNSA), visit:

Images, Video, Text, Credits: CNSA / CASC / CGWIC / ITN TV / AFP /