vendredi 26 août 2016

Hubble Spots an Irregular Island in a Sea of Space

NASA - Hubble Space Telescope patch.

Aug. 26, 2016

This image, courtesy of the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys (ACS), captures the glow of distant stars within NGC 5264, a dwarf galaxy located just over 15 million light-years away in the constellation of Hydra (The Sea Serpent).

Dwarf galaxies like NGC 5264 typically possess around a billion stars — just 1 percent of the number of stars found within the Milky Way. They are usually found orbiting other larger galaxies such as our own, and are thought to form from the material left over from the messy formation of their larger cosmic relatives.

NGC 5264 clearly possesses an irregular shape — unlike the more common spiral or elliptical galaxies — with knots of blue star formation. Astronomers believe that this is due to the gravitational interactions between NGC 5264 and other galaxies nearby. These past flirtations sparked the formation of new generations of stars, which now glow in bright shades of blue.

For more information about the Hubble Space Telescope, visit:

Image credits: ESA/Hubble & NASA/Text credits: European Space AgencyNASA/Ashley Morrow.


SpaceX Dragon Splashes Down with Crucial NASA Research Samples

SpaceX - CRS-9 Dragon Mission patch.

Aug. 26, 2016

SpaceX's Dragon cargo spacecraft splashed down in the Pacific Ocean at 11:47 a.m. EDT Friday, Aug. 26, southwest of Baja California with more than 3,000 pounds of NASA cargo, science and technology demonstration samples from the International Space Station.

The Dragon spacecraft will be taken by ship to a port near Los Angeles, where some cargo will be removed and returned to NASA immediately. Dragon then will be prepared for a return trip to SpaceX's test facility in McGregor, Texas, for processing.

Image above: This image, captured from NASA Television's live coverage, shows SpaceX's Dragon spacecraft departing the International Space Station at 6:10 am EDT Friday, Aug. 26, 2016, after successfully delivering almost 5,000 pounds of supplies and scientific cargo on its ninth resupply mission to the orbiting laboratory. Image Credits: NASA Television.

When it arrived at the station July 20, Dragon delivered the first of two international docking adapters (IDAs) in its external cargo hold, or “trunk.” The IDAs will be used by commercial spacecraft now in development for transporting astronauts to the station as part of NASA's Commercial Crew Program. The initial adapter was installed during an Aug. 19 spacewalk by Expedition 48 Commander Jeff Williams and Flight Engineer Kate Rubins of NASA. The second adapter is being built and will be delivered on a future Dragon cargo resupply mission.

Among the experiment samples returning Friday are those from the Heart Cells study, which is looking at how microgravity affects human heart cells. The U.S. National Laboratory investigation is studying how microgravity changes the human heart, and how those changes vary between individuals. Deep space missions including the journey to Mars will require long periods of space travel, which creates increased risk of health problems such as muscle atrophy, including possible atrophy of the heart muscle. Heart cells cultured aboard the space station for one month will be analyzed for cellular and molecular changes. Results could advance the study of heart disease and the development of drugs and cell replacement therapy.

U.S. Commercial Cargo Craft Departs the International Space Station

Samples will also be returned from two rodent-based investigations, the Mouse Epigenetics and Rodent Research-3-Eli Lilly experiments. The mouse model is useful for showing how much shorter stays by mice in the low-Earth environment can be used to infer how similar conditions may affect future human exploration.

In Mouse Epigenetics, researchers are exploring altered gene expression and DNA by tracking changes in the organs of male mice that spend one month in space, and examining changes in the DNA of their offspring. In Rodent Research-3-Eli Lilly, scientists are looking at rapid loss of bone and muscle mass in the legs and spine, and comparing it to what is experienced by people with muscle wasting diseases or with limited mobility on Earth and testing an antibody known to prevent muscle wasting in mice on Earth. This U.S. National Laboratory experiment is sponsored by pharmaceutical company Eli Lilly and Co. and the Center for the Advancement of Science in Space.

Also returning are samples from the Multi-Omics experiment. This research is analyzing the composition of microbes in the human digestive system and how they may affect the human immune system. Researchers may be able to identify bacterial or metabolic biomarkers that could be useful for astronaut health management, and therefore future human exploration of the solar system.

Dragon is currently the only space station resupply spacecraft able to return a significant amount of cargo to Earth. The spacecraft lifted off from Cape Canaveral Air Force Station in Florida July 18 carrying almost 5,000 pounds of supplies and scientific cargo on the company’s ninth commercial resupply mission to the station.

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 been occupied continuously since November 2000. In that time, more than 200 people and a variety of international and commercial spacecraft have visited the orbiting laboratory. The space station remains the springboard to NASA's next great leap in human space exploration, including the journey to Mars.

Related links:

international docking adapters (IDAs):

Heart Cells study:

Mouse Epigenetics experiment:

Rodent Research-3-Eli Lilly experiment:

Multi-Omics experiment:

Get more information about SpaceX's mission to the International Space Station at:

NASA's Commercial Crew Program:

Find more information about the International Space Station, its crews and their research at:

Image (mentioned), Video, Text, Credits: NASA/Cheryl Warner/Karen Northon/Johnson Space Center/Dan Huot/NASA Television.

Best regards,

Jupiter's Extended Family? A Billion or More

NASA patch.

Aug. 26, 2016

Our galaxy is home to a bewildering variety of Jupiter-like worlds: hot ones, cold ones, giant versions of our own giant, pint-sized pretenders only half as big around.

Astronomers say that in our galaxy alone, a billion or more such Jupiter-like worlds could be orbiting stars other than our sun. And we can use them to gain a better understanding of our solar system and our galactic environment, including the prospects for finding life.

It turns out the inverse is also true -- we can turn our instruments and probes to our own backyard, and view Jupiter as if it were an exoplanet to learn more about those far-off worlds. The best-ever chance to do this is now, with Juno, a NASA probe the size of a basketball court, which arrived at Jupiter in July to begin a series of long, looping orbits around our solar system's largest planet. Juno is expected to capture the most detailed images of the gas giant ever seen. And with a suite of science instruments, Juno will plumb the secrets beneath Jupiter's roiling atmosphere.

Image above: Comparing Jupiter with Jupiter-like planets that orbit other stars can teach us about those distant worlds, and reveal new insights about our own solar system's formation and evolution. (Illustration) Image Credits: NASA/JPL-Caltech.

It will be a very long time, if ever, before scientists who study exoplanets -- planets orbiting other stars -- get the chance to watch an interstellar probe coast into orbit around an exo-Jupiter, dozens or hundreds of light-years away. But if they ever do, it's a safe bet the scene will summon echoes of Juno.

"The only way we're going to ever be able to understand what we see in those extrasolar planets is by actually understanding our system, our Jupiter itself," said David Ciardi, an astronomer with NASA's Exoplanet Science Institute (NExSci) at Caltech.

Not all Jupiters are created equal

Juno's detailed examination of Jupiter could provide insights into the history, and future, of our solar system. The tally of confirmed exoplanets so far includes hundreds in Jupiter's size-range, and many more that are larger or smaller.

The so-called hot Jupiters acquired their name for a reason: They are in tight orbits around their stars that make them sizzling-hot, completing a full revolution -- the planet's entire year -- in what would be a few days on Earth. And they're charbroiled along the way.

But why does our solar system lack a "hot Jupiter?" Or is this, perhaps, the fate awaiting our own Jupiter billions of years from now -- could it gradually spiral toward the sun, or might the swollen future sun expand to engulf it?

Not likely, Ciardi says; such planetary migrations probably occur early in the life of a solar system.

"In order for migration to occur, there needs to be dusty material within the system," he said. "Enough to produce drag. That phase of migration is long since over for our solar system."

Jupiter itself might already have migrated from farther out in the solar system, although no one really knows, he said.

Looking back in time

If Juno's measurements can help settle the question, they could take us a long way toward understanding Jupiter's influence on the formation of Earth -- and, by extension, the formation of other "Earths" that might be scattered among the stars.

"Juno is measuring water vapor in the Jovian atmosphere," said Elisa Quintana, a research scientist at the NASA Ames Research Center in Moffett Field, California. "This allows the mission to measure the abundance of oxygen on Jupiter. Oxygen is thought to be correlated with the initial position from which Jupiter originated."

If Jupiter's formation started with large chunks of ice in its present position, then it would have taken a lot of water ice to carry in the heavier elements which we find in Jupiter.  But a Jupiter that formed farther out in the solar system, then migrated inward, could have formed from much colder ice, which would carry in the observed heavier elements with a smaller amount of water.  If Jupiter formed more directly from the solar nebula, without ice chunks as a starter, then it should contain less water still.  Measuring the water is a key step in understanding how and where Jupiter formed.

That's how Juno's microwave radiometer, which will measure water vapor, could reveal Jupiter's ancient history.

"If Juno detects a high abundance of oxygen, it could suggest that the planet formed farther out," Quintana said.

A probe dropped into Jupiter by NASA’s Galileo spacecraft in 1995 found high winds and turbulence, but the expected water seemed to be absent. Scientists think Galileo's one-shot probe just happened to drop into a dry area of the atmosphere, but Juno will survey the entire planet from orbit.

The chaotic early years

Where Jupiter formed, and when, also could answer questions about the solar system's "giant impact phase," a time of crashes and collisions among early planet-forming bodies that eventually led to the solar system we have today.

Our solar system was extremely accident-prone in its early history -- perhaps not quite like billiard balls caroming around, but with plenty of pileups and fender-benders.

"It definitely was a violent time," Quintana said. "There were collisions going on for tens of millions of years. For example, the idea of how the moon formed is that a proto-Earth and another body collided; the disk of debris from this collision formed the moon. And some people think Mercury, because it has such a huge iron core, was hit by something big that stripped off its mantle; it was left with a large core in proportion to its size."

Part of Quintana's research involves computer modeling of the formation of planets and solar systems. Teasing out Jupiter's structure and composition could greatly enhance such models, she said. Quintana already has modeled our solar system's formation, with Jupiter and without, yielding some surprising findings.

"For a long time, people thought Jupiter was essential to habitability because it might have shielded Earth from the constant influx of impacts [during the solar system's early days] which could have been damaging to habitability," she said. "What we've found in our simulations is that it's almost the opposite. When you add Jupiter, the accretion times are faster and the impacts onto Earth are far more energetic. Planets formed within about 100 million years; the solar system was done growing by that point," Quintana said.

"If you take Jupiter out, you still form Earth, but on timescales of billions of years rather than hundreds of millions. Earth still receives giant impacts, but they're less frequent and have lower impact energies," she said.

Getting to the core

Another critical Juno measurement that could shed new light on the dark history of planetary formation is the mission's gravity science experiment. Changes in the frequency of radio transmissions from Juno to NASA's Deep Space Network will help map the giant planet's gravitational field.

Knowing the nature of Jupiter's core could reveal how quickly the planet formed, with implications for how Jupiter might have affected Earth's formation.

And the spacecraft's magnetometers could yield more insight into the deep internal structure of Jupiter by measuring its magnetic field.

"We don't understand a lot about Jupiter's magnetic field," Ciardi said. "We think it's produced by metallic hydrogen in the deep interior. Jupiter has an incredibly strong magnetic field, much stronger than Earth's."

Mapping Jupiter's magnetic field also might help pin down the plausibility of proposed scenarios for alien life beyond our solar system.

Earth's magnetic field is thought to be important to life because it acts like a protective shield, channeling potentially harmful charged particles and cosmic rays away from the surface.

"If a Jupiter-like planet orbits its star at a distance where liquid water could exist, the Jupiter-like planet itself might not have life, but it might have moons which could potentially harbor life," he said.

An exo-Jupiter’s intense magnetic field could protect such life forms, he said. That conjures visions of Pandora, the moon in the movie "Avatar" inhabited by 10-foot-tall humanoids who ride massive, flying predators through an exotic alien ecosystem.

Juno's findings will be important not only to understanding how exo-Jupiters might influence the formation of exo-Earths, or other kinds of habitable planets. They'll also be essential to the next generation of space telescopes that will hunt for alien worlds. The Transiting Exoplanet Survey Satellite (TESS) will conduct a survey of nearby bright stars for exoplanets beginning in June 2018, or earlier. The James Webb Space Telescope, expected to launch in 2018, and WFIRST (Wide-Field Infrared Survey Telescope), with launch anticipated in the mid-2020s, will attempt to take direct images of giant planets orbiting other stars.

"We're going to be able to image planets and get spectra," or light profiles from exoplanets that will reveal atmospheric gases, Ciardi said. Juno's revelations about Jupiter will help scientists to make sense of these data from distant worlds.

"Studying our solar system is about studying exoplanets," he said. "And studying exoplanets is about studying our solar system. They go together."

Related links:


Distant Planets:


To learn more about a few of the known exo-Jupiters, visit:

Image (mentioned), Text, Credits: NASA/Tony Greicius/JPL/Preston Dyches/NASA Exoplanet Program, written by Pat Brennan.


Spitzer Space Telescope Begins 'Beyond' Phase

NASA - Spitzer Space Telescope patch.

Aug. 26, 2016

Spitzer Beyond

Video above: NASA’s Spitzer Space Telescope, which launched Aug. 25, 2003, will begin the “Beyond” phase of its mission on Oct. 1, 2016. Spitzer has been operating beyond the limits that were set for it at the beginning of its mission, and making discoveries in unexpected areas of science, such as exoplanets.

Celebrating the spacecraft's ability to push the boundaries of space science and technology, NASA's Spitzer Space Telescope team has dubbed the next phase of its journey "Beyond."

"Spitzer is operating well beyond the limits that were set for it at the beginning of the mission," said Michael Werner, the project scientist for Spitzer at NASA's Jet Propulsion Laboratory in Pasadena, California. "We never envisioned operating 13 years after launch, and scientists are making discoveries in areas of science we never imagined exploring with the spacecraft."

NASA recently granted the spacecraft a two-and-a-half-year mission extension. This Beyond phase of the Spitzer mission will explore a wide range of topics in astronomy and cosmology, as well as planetary bodies in and out of our solar system.

Image above: his diagram shows how the different phases of Spitzer’s mission relate to its location relative to the Earth over time. Image Credits: NASA/JPL-Caltech.

Because of Spitzer's orbit and age, the Beyond phase presents a variety of new engineering challenges. Spitzer trails Earth in its journey around the sun, but because the spacecraft travels slower than Earth, the distance between Spitzer and Earth has widened over time. As Spitzer gets farther away, its antenna must be pointed at higher angles toward the sun to communicate with Earth, which means that parts of the spacecraft will experience more and more heat. At the same time, Spitzer's solar panels point away from the sun and will receive less sunlight, so the batteries will be under greater stress.  To enable this riskier mode of operations, the mission team will have to override some autonomous safety systems.

“Balancing these concerns on a heat-sensitive spacecraft will be a delicate dance, but engineers are hard at work preparing for the new challenges in the Beyond phase,” said Mark Effertz, the Spitzer spacecraft chief engineer at Lockheed Martin Space Systems Company, Littleton, Colorado, which built the spacecraft.

Spitzer, which launched on Aug. 25, 2003, has consistently adapted to new scientific and engineering challenges during its mission, and the team expects it will continue to do so during the "Beyond" phase, which begins Oct. 1. The selected research proposals for the Beyond phase, also known as Cycle 13, include a variety of objects that Spitzer wasn't originally planned to address -- such as galaxies in the early universe, the black hole at the center of the Milky Way and exoplanets.

Image above: This artist's concept shows NASA's Spitzer Space Telescope. Spitzer begins its "Beyond" mission phase on Oct. 1, 2016. The spacecraft is depicted in the orientation it assumes to establish communications with ground stations. Image Credits: NASA/JPL-Caltech.

"We never even considered using Spitzer for studying exoplanets when it launched," said Sean Carey of NASA's Spitzer Science Center at Caltech in Pasadena. "It would have seemed ludicrous back then, but now it's an important part of what Spitzer does."

Spitzer’s exoplanet exploration

Spitzer has many qualities that make it a valuable asset in exoplanet science, including an extremely accurate star-targeting system and the ability to control unwanted changes in temperature. Its stable environment and ability to observe stars for long periods of time led to the first detection of light from known exoplanets in 2005. More recently, Spitzer’s Infrared Array Camera (IRAC) has been used for finding exoplanets using the "transit" method -- looking for a dip in a star's brightness that corresponds to a planet passing in front of it. This brightness change needs to be measured with exquisite accuracy to detect exoplanets. IRAC scientists have created a special type of observation to make such measurements, using single pixels within the camera.

Another planet-finding technique that Spitzer uses, but was not designed for, is called microlensing. When a star passes in front of another star, the gravity of the first star can act as a lens, making the light from the more distant star appear brighter. Scientists are using microlensing to look for a blip in that brightening, which could mean that the foreground star has a planet orbiting it. Spitzer and the ground-based Polish Optical Gravitational Lensing Experiment (OGLE) were used together to find one of the most distant planets known outside the solar system, as reported in 2015. This type of investigation is made possible by Spitzer’s increasing distance from Earth, and could not have been done early in the mission.

Peering into the early universe

Understanding the early universe is another area where Spitzer has broken ground. IRAC was designed to detect remote galaxies roughly 12 billion light-years away -- so distant that their light has been traveling for roughly 88 percent of the history of the universe. But now, thanks to collaborations between Spitzer and NASA’s Hubble Space Telescope, scientists can peer even further into the past. The farthest galaxy ever seen, GN-z11, was characterized in a 2016 study using data from these telescopes. GN-z11 is about 13.4 billion light-years away, meaning its light has been traveling since 400 million years after the big bang.  

"When we designed the IRAC instrument, we didn't know those more distant galaxies existed," said Giovanni Fazio, principal investigator of IRAC, based at the Harvard Smithsonian Center for Astrophysics in Cambridge, Massachusetts. "The combination of the Hubble Space Telescope and Spitzer has been fantastic, with the telescopes working together to determine their distance, stellar mass and age."

Closer to home, Spitzer advanced astronomers' understanding of Saturn when scientists using the observatory discovered the planet's largest ring in 2009. Most of the material in this ring -- consisting of ice and dust -- begins 3.7 million miles (6 million kilometers) from Saturn and extends about 7.4 million miles (12 million kilometers) beyond that. Though the ring doesn't reflect much visible light, making it difficult for Earth-based telescopes to see, Spitzer could detect the infrared glow from the cool dust.

The multiple phases of Spitzer

Spitzer reinvented itself in May 2009 with its warm mission, after the depletion of the liquid helium coolant that was chilling its instruments since August 2003. At the conclusion of the "cold mission," Spitzer’s Infrared Spectrograph and Multiband Imaging Photometer stopped working, but two of the four cameras in IRAC persisted. Since then, the spacecraft has made numerous discoveries despite operating in warmer conditions (which, at about minus 405 Fahrenheit or 30 Kelvin, is still cold by Earthly standards).

"With the IRAC team and the Spitzer Science Center team working together, we've really learned how to operate the IRAC instrument better than we thought we could," Fazio said. "The telescope is also very stable and in an excellent orbit for observing a large part of the sky."

Spitzer's Beyond mission phase will last until the commissioning phase of NASA's James Webb Space Telescope, currently planned to launch in October 2018. Spitzer is set to identify targets that Webb can later observe more intensely.

"We are very excited to continue Spitzer in its Beyond phase. We fully expect new, exciting discoveries to be made over the next two-and-a-half years," said Suzanne Dodd, project manager for Spitzer, based at JPL.

JPL manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena, California. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA. For more information about Spitzer, visit:

Images (mentioned), Video (mentioned), Text, Credits: NASA/Tony Greicius/JPL/Elizabeth Landau.


jeudi 25 août 2016

Internaut Day and the World Wide Web

CERN - European Organization for Nuclear Research logo.

August 25, 2016

Image above: Tim Berners-Lee, inventor of the World Wide Web, pictured in 1994. In front of him shows a computer displaying an early version of the web. (Image: CERN).

Internaut day is being celebrated around the world on 23 August to mark the invention of the World Wide Web. An “internaut” is a person who possesses a thorough knowledge of how to use the Internet and its history. But what is the history of the web?

In March 1989, CERN scientist Tim Berners-Lee wrote a proposal to develop a distributed information system for the Laboratory. By December 1990, the world's first website and server were ready to go live at CERN. At that time, the World Wide Web enabled scientists to share information across the world; the source code was later released into the public domain in April 1993.

Image above: A statement outlining the release of the World Wide Web into the public domain in April 1993. (Image: CERN).

Although 23 August does not mark an exact anniversary in the creation of the web, it does give an opportunity to appreciate the ease of communication that it provides and how it has become vital in our everyday lives.


CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 22 Member States.

Find out more about the many important milestones of the birth of the web:

World's first website:

For more information about the European Organization for Nuclear Research (CERN), visit:

Images (mentioned), Text, Credits: CERN/Kathryn Coldham.

Best regards,

NASA's Juno to Soar Closest to Jupiter This Saturday

NASA - JUNO Mission logo.

Aug. 25, 2016

Image above: This dual view of Jupiter was taken on August 23, when NASA’s Juno spacecraft was 2.8 million miles (4.4 million kilometers) from the gas giant planet on the inbound leg of its initial 53.5-day capture orbit. Image Credits: NASA/JPL-Caltech/SwRI/MSSS.

This Saturday at 5:51 a.m. PDT, (8:51 a.m. EDT, 12:51 UTC) NASA's Juno spacecraft will get closer to the cloud tops of Jupiter than at any other time during its prime mission. At the moment of closest approach, Juno will be about 2,500 miles (4,200 kilometers) above Jupiter's swirling clouds and traveling at 130,000 mph (208,000 kilometers per hour) with respect to the planet. There are 35 more close flybys of Jupiter scheduled during its prime mission (scheduled to end in February of 2018). The Aug. 27 flyby will be the first time Juno will have its entire suite of science instruments activated and looking at the giant planet as the spacecraft zooms past.

"This is the first time we will be close to Jupiter since we entered orbit on July 4," said Scott Bolton, principal investigator of Juno from the Southwest Research Institute in San Antonio. "Back then we turned all our instruments off to focus on the rocket burn to get Juno into orbit around Jupiter. Since then, we have checked Juno from stem to stern and back again. We still have more testing to do, but we are confident that everything is working great, so for this upcoming flyby Juno's eyes and ears, our science instruments, will all be open."

"This is our first opportunity to really take a close-up look at the king of our solar system and begin to figure out how he works," Bolton said.

While the science data from the pass should be downlinked to Earth within days, interpretation and first results are not expected for some time.

"No other spacecraft has ever orbited Jupiter this closely, or over the poles in this fashion," said Steve Levin, Juno project scientist from NASA's Jet Propulsion Laboratory in Pasadena, California. "This is our first opportunity and there are bound to be surprises. We need to take our time to make sure our conclusions are correct." 

Not only will Juno's suite of eight science instruments be on, the spacecraft's visible light imager -- JunoCam will also be snapping some closeups. A handful of JunoCam images, including the highest resolution imagery of the Jovian atmosphere and the first glimpse of Jupiter's north and south poles, are expected to be released during the later part of next week.

The Juno spacecraft launched on Aug. 5, 2011, from Cape Canaveral, Florida. JPL manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio. Juno is part of NASA's New Frontiers Program, which is managed at NASA's Marshall Space Flight Center in Huntsville, Alabama, for NASA's Science Mission Directorate. Lockheed Martin Space Systems, Denver, built the spacecraft. Caltech, in Pasadena, California, manages JPL for NASA.

More information on the Juno mission is available at:

Follow the mission on Facebook and Twitter at:

Image (mentioned), Text, Credits: NASA/Dwayne Brown/Laurie Cantillo/Tony Greicius/JPL/DC Agle.


Dragon Packed for Friday Morning Departure and Splashdown

ISS - Expedition 48 Mission patch.

August 25, 2016

The SpaceX Dragon cargo craft has been packed with science experiments and gear for return to Earth and analysis by NASA engineers. Robotics controllers on the ground will maneuver the Canadarm2 to detach Dragon from the Harmony module Thursday afternoon.

Astronauts Takuya Onishi and Kate Rubins will command Canadarm2 to release Dragon at 6:10 a.m. EDT Friday. It will splashdown off the Pacific coast of Baja California a few hours later, then be retrieved and shipped back to Los Angeles by SpaceX personnel.

Image above: The SpaceX Dragon is pictured as the International Space Station orbited over the English Channel.

Less than two weeks later, a trio of Expedition 48 crew members will return to Earth inside the Soyuz TMA-20M spacecraft. Commander Jeff Williams and Flight Engineers Oleg Skripochka and Alexey Ovchinin are due to end their stay at the International Space Station on Sept. 6 and land in Kazakhstan.

Meanwhile, the space station crew is still participating in a wide variety of ongoing space research to benefit people living on Earth and in space. The crew conducted human research activities today exploring how long-term space missions affect an astronaut’s metabolism, digestion and blood pressure.

International Space Station (ISS):

Expedition 48:

Space Station Research and Technology:

Image, Text, Credits: NASA/Mark Garcia.


Rosetta captures comet outburst

ESA - Rosetta Mission patch.

25 August 2016

In unprecedented observations made earlier this year, Rosetta unexpectedly captured a dramatic comet outburst that may have been triggered by a landslide.

Nine of Rosetta’s instruments, including its cameras, dust collectors, and gas and plasma analysers, were monitoring the comet from about 35 km in a coordinated planned sequence when the outburst happened on 19 February.

Comet outburst

“Over the last year, Rosetta has shown that although activity can be prolonged, when it comes to outbursts, the timing is highly unpredictable, so catching an event like this was pure luck,” says Matt Taylor, ESA’s Rosetta project scientist.

“By happy coincidence, we were pointing the majority of instruments at the comet at this time, and having these simultaneous measurements provides us with the most complete set of data on an outburst ever collected.”

Evolution of a comet outburst

The data were sent to Earth only a few days after the outburst, but subsequent analysis has allowed a clear chain of events to be reconstructed, as described in a paper led by Eberhard Grün of the Max-Planck-Institute for Nuclear Physics, Heidelberg, accepted for publication in Monthly Notices of the Royal Astronomical Society.

A strong brightening of the comet’s dusty coma was seen by the OSIRIS wide-angle camera at 09:40 GMT, developing in a region of the comet that was initially in shadow.

Over the next two hours, Rosetta recorded outburst signatures that exceeded background levels in some instruments by factors of up to a hundred. For example, between about 10:00–11:00 GMT, ALICE saw the ultraviolet brightness of the sunlight reflected by the nucleus and the emitted dust increase by a factor of six, while ROSINA and RPC detected a significant increase in gas and plasma, respectively, around the spacecraft, by a factor of 1.5–2.5.

In addition, MIRO recorded a 30ºC rise in temperature of the surrounding gas.

Shortly after, Rosetta was blasted by dust: GIADA recorded a maximum hit count at around 11:15 GMT. Almost 200 particles were detected in the following three hours, compared with a typical rate of 3–10 collected on other days in the same month.

Which instruments detected the outburst?

At the same time, OSIRIS narrow-angle camera images began registering dust grains emitted during the blast. Between 11:10 GMT and 11:40 GMT, a transition occurred from grains that were distant or slow enough to appear as points in the images, to those either close or fast enough to be captured as trails during the exposures.

In addition, the startrackers, which are used to navigate and help control Rosetta’s attitude, measured an increase in light scattered from dust particles as a result of the outburst.

The startrackers are mounted at 90º to the side of the spacecraft that hosts the majority of science instruments, so they offered a unique insight into the 3D structure and evolution of the outburst.

Astronomers on Earth also noted an increase in coma density in the days after the outburst.

Location of the outburst

By examining all of the available data, scientists believe they have identified the source of the outburst.

“From Rosetta’s observations, we believe the outburst originated from a steep slope on the comet’s large lobe, in the Atum region,” says Eberhard.

The fact that the outburst started when this area just emerged from shadow suggests that thermal stresses in the surface material may have triggered a landslide that exposed fresh water ice to direct solar illumination. The ice then immediately turned to gas, dragging surrounding dust with it to produce the debris cloud seen by OSIRIS.

“Combining the evidence from the OSIRIS images with the long duration of the GIADA dust impact phase leads us to believe that the dust cone was very broad,” says Eberhard.

“As a result, we think the outburst must have been triggered by a landslide at the surface, rather than a more focused jet bringing fresh material up from within the interior, for example.”

“We’ll continue to analyse the data not only to dig into the details of this particular event, but also to see if it can help us better understand the many other outbursts witnessed over the course of the mission,” adds Matt.

“It’s great to see the instrument teams working together on the important question of how cometary outbursts are triggered.”

Notes for Editors:

“The 19 Feb. 2016 outburst of comet 67P/CG: A Rosetta multi-instrument study,” by E. Grün et al is published in the Monthly Notices of the Royal Astronomical Society. doi: 10.1093/mnras/stw2088

Related links:

Comet viewer tool:

Where is Rosetta?:

For more information about Rosetta mission, visit:

Rosetta overview:

Rosetta in depth:

Images, Animation, Text, Credits: ESA/Rosetta/NavCam – CC BY-SA IGO 3.0/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA; all data from Grün et al (2016)/ATG medialab/ESA Rosetta project scientist, Matt Taylor/Markus Bauer.

Best regards,

mercredi 24 août 2016

NASA's WISE, Fermi Missions Reveal a Surprising Blazar Connection

NASA - WISE Mission logo / NASA - Fermi Gamma-ray Space Telescope logo.

Aug. 24, 2016

Astronomers studying distant galaxies powered by monster black holes have uncovered an unexpected link between two very different wavelengths of the light they emit, the mid-infrared and gamma rays. The discovery, which was accomplished by comparing data from NASA’s Wide-field Infrared Survey Explorer (WISE) and Fermi Gamma-ray Space Telescope, has enabled the researchers to uncover dozens of new blazar candidates.

Francesco Massaro at the University of Turin in Italy and Raffaele D’Abrusco at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, show for the first time that the mid-infrared colors of blazars in WISE data correlate to an equivalent measurement of their gamma-ray output.

"This connection links two vastly different forms of light over an energy range spanning a factor of 10 billion," said Massaro. "Ultimately, it will help us decipher how supermassive black holes in these galaxies manage to convert the matter around them into vast amounts of energy."

Graphic above: An analysis of blazar properties observed by the Wide-field Infrared Survey Explorer (WISE) and Fermi's Large Area Telescope (LAT) reveal a correlation in emissions from the mid-infrared to gamma rays, an energy range spanning a factor of 10 billion. When plotted by gamma-ray and mid-infrared colors, confirmed Fermi blazars (gold dots) form a unique band not shared by other sources beyond our galaxy. A blue line marks the best fit of these values. The relationship allows astronomers to identify potential new gamma-ray blazars by studying WISE infrared data. Graphic Credits: NASA's Goddard Space Flight Center/Francesco Massaro, University of Turin.

Blazars constitute more than half of the discrete gamma-ray sources seen by Fermi's Large Area Telescope (LAT). At the heart of a blazar lies a supersized black hole with millions of times the sun's mass surrounded by a disk of hot gas and dust. As material in the disk falls toward the black hole, some of it forms dual jets that blast subatomic particles straight out of the disk in opposite directions at nearly the speed of light. A blazar appears bright to Fermi for two reasons. Its jets produce many gamma rays, the highest-energy form of light, and we happen to be viewing the galaxy face on, which means one of its jets is pointing in our direction.

From January to August 2010, NASA's WISE mapped the entire sky in four infrared wavelengths, cataloging more than half a billion sources. In 2011, Massaro, D’Abrusco and their colleagues began using WISE data to investigate Fermi blazars.

"WISE made it possible to explore the mid-infrared colors of known gamma-ray blazars," said D’Abrusco. "We found that when we plotted Fermi blazars by their WISE colors in a particular way, they occupied a distinctly different part of the plot than other extragalactic gamma-ray sources."

The scientists detail new aspects of the infrared/gamma-ray connection in a paper published in The Astrophysical Journal on Aug. 9. They say the electrons, protons and other particles accelerated in blazar jets leave a specific "fingerprint" in the infrared light they emit. This same pattern is also clearly evident in their gamma rays. The relationship effectively connects the dots for blazars across an enormous swath of the electromagnetic spectrum.

Image above: Black-hole-powered galaxies called blazars are the most common sources detected by NASA's Fermi Gamma-ray Space Telescope. As matter falls toward the supermassive black hole at the galaxy's center, some of it is accelerated outward at nearly the speed of light along jets pointed in opposite directions. When one of the jets happens to be aimed in the direction of Earth, as illustrated here, the galaxy appears especially bright and is classified as a blazar. Image Credits: M. Weiss/CfA.

About a thousand Fermi sources remain unassociated with known objects at any other wavelength. Astronomers suspect many of these are blazars, but there isn't enough information to classify them. The infrared/gamma-ray connection led the authors to search for new blazar candidates among WISE infrared sources located within the positional uncertainties of Fermi's unidentified gamma-ray objects. When the researchers applied this relationship to Fermi's unknown sources, they quickly found 130 potential blazars. Efforts are now under way to confirm the nature of these objects through follow-up studies and to search for additional candidates using the WISE connection.

"About a third of the gamma-ray objects seen by Fermi remained unknown in the most recent catalog, and this result represents an important advance in understanding their natures," said David Thompson, a Fermi deputy project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

NASA's Jet Propulsion Laboratory in Pasadena, California, manages and operates WISE for NASA's Science Mission Directorate in Washington. The spacecraft was put into hibernation mode in 2011 after twice scanning the entire sky, thereby completing its main objectives. In September 2013, WISE was reactivated, renamed NEOWISE and assigned a new mission to assist NASA's efforts to identify potentially hazardous near-Earth objects.

NASA's Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy and with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.

For more information on Fermi, visit:

For more information on WISE, visit:

Image and Graphic (mentioned), Text, Credits: NASA/Ashley Morrow/JPL/Elizabeth Landau/NASA's Goddard Space Flight Center, by Francis Reddy.


Jeff Williams Racks Up New Time-Spent-In-Space Record

ISS - Expedition 48 Mission patch.

Aug. 24, 2016

You don’t have to go to Rio to see Americans breaking records – you can find one orbiting 250 miles above Earth.

On Wednesday, Aug. 24, NASA astronaut and Expedition 48 Commander Jeff Williams surpassed 520 days living in space, breaking Scott Kelly’s previous record for most cumulative time spent in space by a U.S. astronaut, set during Kelly’s year-long mission.

Scott Kelly Congratulates Jeff Williams on Breaking Record

Video above: Former astronaut Scott Kelly called space station Commander Jeff Williams from Mission Control Center to congratulate him for establishing a new NASA astronaut record for cumulative time in space. Video Credit: NASA.

By the time Williams returns home on Sept. 6, he’ll leave us with a new total of 534 days.

The first 10 of Williams’ 520 days were spent on Space Shuttle Atlantis during STS-101 in 2000, back when the International Space Station was still under construction. As a flight engineer and spacewalker for the mission, he helped prepare the space station for its first crew, which arrived less than five months later. At that point, the space station consisted of just the Zarya module and the Unity node.

When Williams returned in 2006 for his first long duration stay as part of Expedition 13, the space station had grown significantly. The Russian Zvezda service module, the U.S. Destiny laboratory and the Quest airlock all had been installed in the intervening years, as well as several segments of the station’s backbone and solar arrays. In addition, the science experiments that the orbiting laboratory was built for were already going on, with subjects ranging from capillary flow to the effects of microgravity on astronauts’ central nervous systems. And Williams was able to add two additional spacewalks to his resume, setting up additional experiments on the exterior of the station and replacing equipment.

Image above: Astronaut Jeff WIlliams in pictured in 2006 when he was a crew member during Expedition 13. Image Credit: NASA.

After six months at the space station, Williams returned to Earth and waited three years for another visit. He returned in 2009 for his first stint commanding the space station. While he was away, the station continued to grow, adding the Harmony node, the European Columbus laboratory and the Japanese Kibo laboratory. And over the course of his stay for Expedition 21/22, he saw the arrival of the Poisk Russian Mini Research Module and two space shuttle missions, one of which delivered Tranquility node and the space station cupola.

Williams began his current visit to the station with more than 362 days in space. He launched to the station from the Baikonur Cosmodrome in Kazakhstan on March 18, and kicked off his third long-duration mission as part of Expedition 47/48. Since his last visit, the space station had been declared complete, but he’s still finding some construction work to do – he was on board for the arrival and deployment of the Bigelow Expandable Activity Module, and took part in Friday’s spacewalk to add the international docking adapter that will allow future commercial crew vehicles to dock to the station.

When he leaves the station again, the 534 days that Williams will have racked up will earn him the 14th spot on the all-time endurance list for astronauts and cosmonauts, in addition to the top ranking for U.S. astronauts. But he won’t hold on to the position for long – Peggy Whitson is scheduled to surpass him in 2017 during her next mission, which launches in November.

Related links:

International Space Station (ISS):

Expedition 48:

Image (mentioned), Video (mentioned), Text, Credits: NASA/Mark Garcia.


35 Years On, Voyager's Legacy Continues at Saturn

NASA - Voyager 1 & 2 Mission patch.

Aug. 24, 2016

Saturn, with its alluring rings and numerous moons, has long fascinated stargazers and scientists. After an initial flyby of Pioneer 11 in 1979, humanity got a second, much closer look at this complex planetary system in the early 1980s through the eyes of NASA's twin Voyager spacecraft.

Image above: Up-close views from the Voyagers, like this one from Voyager 2, showed Saturn and its rings as never before. Image Credits: NASA/JPL-Caltech.

Voyager 2 made its closest approach to Saturn 35 years ago -- on Aug. 25, 1981. What the Voyagers revealed at the planet was so phenomenal that, just one year later, a joint American and European working group began discussing a mission that would carry on Voyager's legacy at Saturn. That mission -- named Cassini -- has been studying the Saturn system since 2004. Cassini has followed up on many of Voyager's discoveries, and has deepened our understanding of what some might call a "mini solar system."

"Saturn, like all of the planets the Voyagers visited, was full of exciting discoveries and surprises," said Ed Stone, Voyager project scientist at Caltech in Pasadena, California. "By giving us unprecedented views of the Saturn system, Voyager gave us plenty of reasons to go back for a closer look."

Many Mysterious Moons

Voyager's Saturn flybys provided a thrilling look at the planet's moons -- a diverse menagerie of worlds, each with unique character and charm. Voyager's images transformed the moons from points of light to fully realized places. Dramatic landscapes on Tethys, Dione, Rhea, Iapetus and other moons tantalized scientists with features hinting at tortured pasts.

"The stars of the Saturn system are the moons, which surprised all of us on both the Voyager and Cassini missions," said Linda Spilker, project scientist for Cassini at NASA's Jet Propulsion Laboratory, Pasadena. Spilker also served on the Voyager science team.

Image above: Titan was a high priority for the Voyager flybys at Saturn. The two spacecraft saw tantalizing hints of the structure and composition of the giant moon's dense atmosphere. Image Credits: NASA/JPL-Caltech.

One of the key findings of the Voyagers' visits to Saturn was that the planet's moons had evidence of past geological activity and that Enceladus -- the brightest, most reflective planetary body scientists had ever seen -- could still be active.

Cassini set out to delve deeper into the nature of these moons, and found that, indeed, icy Enceladus has geysers erupting to this day. Cassini also confirmed that Enceladus is the source of Saturn's E ring, which was suggested by Voyager. But while Voyager images of wispy terrain hinted at ice volcanoes on Dione, Cassini found this feathery coating was actually a system of bright canyons.

…Especially Titan

Titan, Saturn's largest moon, was a high-priority target for the Voyager mission. Gerard Kuiper, for whom the Kuiper Belt is named, had discovered in 1944 that Titan had an atmosphere containing methane. Observations from both Voyagers showed that Titan's atmosphere was primarily composed of nitrogen, with a few percent methane and smaller amounts of other complex hydrocarbons, such as ethane, propane and acetylene. No other moon in the solar system has a dense atmosphere.

Mission planners mapped out a path through the Saturn system that provided the gravitational boost needed to send Voyager 2 onward to Uranus. But because of intense interest in Titan's atmosphere, the giant moon was the higher priority. In fact, the team would have directed Voyager 2 much closer to Titan if Voyager 1 had not been successful in observing it.

Image above: This psychedelic false-color view of Saturn from Voyager 2 reveals structure in the planet's banded clouds. Image Credits: NASA/JPL-Caltech.

"To fly close to Titan, Voyager 2 would have swung upward out of the plane of the planets, and couldn't have gone on to visit any others," Stone said. "It was fortunate that Voyager 1's observations of Titan went flawlessly, so that Voyager 2 could continue traveling to Uranus and Neptune."

To the Voyagers, Titan appeared as a featureless orange ball because of dense haze in its atmosphere. Seeing through this haze was a chief goal of the Cassini mission. Cassini carried cameras with infrared vision that could see through the haze, a radar that could map the surface in detail, and the European Huygens probe, which landed on the moon's frigid surface on Jan. 14, 2005. We now know, thanks to Cassini, that smoggy Titan has methane lakes and flooded canyons.

New Shapes and Sizes

Voyager discovered four new moons and sharpened our view of some that were previously known. The spacecraft also revealed how the gravitational pull of these satellites causes ripples in Saturn's rings, much like the wake of a ship on the sea. There were also surprising gaps in the rings, some caused by moons embedded within them.

Voyager also revealed an immense hexagonal feature in the clouds that surrounded Saturn's north pole, which Cassini found was still going strong a quarter century later. Additionally, Voyager measured the wind speeds, temperature and density of Saturn's atmosphere. With Voyager's measurements as a starting point, Cassini further explored how Saturn's atmosphere changes with the seasons.

Lingering Mysteries of Saturn and Beyond

While both missions have vastly improved our understanding of Saturn, its rings and moons, there are still mysteries galore. For example, the exact length of Saturn's day continues to elude researchers. The Voyagers measured it to be a period of 10.66 hours, but Cassini has measured two different, changing periods in the north and south.

Image above: Voyager 2 saw hints that Enceladus might be active, but the icy moon held onto its secrets until the arrival of the Cassini mission. Image Credits: NASA/JPL-Caltech.

Voyager also made the first up-close observations of Saturn's rings, discovering new thin and faint rings, along with the ghostly features called spokes. But despite more than a decade of observations with Cassini, scientists are still unsure about the age of the rings -- they could be hundreds of millions of years old, or several billion. Cassini, in turn, has prompted new questions of its own, such as whether the ocean worlds Enceladus and Titan could be habitable.

"The twin Voyagers rewrote the textbooks on Saturn, its rings and moons, and we couldn't wait to go back with Cassini," Spilker said. "New mysteries uncovered by Cassini will await the next missions to follow in the footsteps of Voyager."

Voyager 2’s mission of discovery continues to this day. It is now part of the Heliophysics System Observatory, a collection of missions that explore our space environment, and which contribute to protecting future missions on their journeys. Voyager now explores what's known as the interstellar boundary region, where material blowing out from the sun encounters similar winds from other stars.

The two Voyager spacecraft, as well as Cassini, were built by JPL, which continues to operate the three missions. JPL is a division of Caltech. For more information about the Voyager spacecraft, visit:

Images (mentioned), Text, Credits: NASA/Tony Greicius/JPL, written by Elizabeth Landau and Preston Dyches.


Arianespace orbits two satellites for Intelsat

ARIANESPACE - Ariane 5 ECA / Flight VA232 Mission poster.

Aug 24, 2016

Arianespace has successfully launched the Intelsat 33e and Intelsat 36 satellites for Intel-sat, the world’s leading provider of satellite services. VA232 was the first Ariane 5 dual launch entirely dedicated to Intelsat satellites.

Image above: Ariane 5 during its rollout to the Spaceport’s ELA-3 launch zone. Flight VA232. Intelsat 33e and Intelsat 36. Image Credit: Arianespace.

Arianespace’s sixth launch of 2016, the fourth using an Ariane 5, took place on Wednes-day, August 24, 2016 at 07:16 p.m. (local time) from the Guiana Space Center in Kourou, French Guiana. This mission was the 73rd successful Ariane 5 launch in a row. It also reflected Ariane 5’s steadily increasing performance, as the heavy launcher set a new record by lofting 10,735 kg. into geostationary transfer orbit (GTO), outpacing the previ-ous record of 10,730 kg., set in June 2016.

Video above: Liftoff of Arianespace’s Ariane 5 with Intelsat 33e and Intelsat 36. Video Credit: Arianespace.

Today’s launch was Arianespace’s second of the year for Intelsat. Arianespace has now launched 58 satellites for this operator, further strengthening a partnership that spans more than three decades.

Arianespace and Intelsat: partners for more than 30 years

Intelsat is the world’s leading provider of satellite services in terms of revenue and in-orbit capacity, with a fleet of approximately 50 satellites. It delivers high-performance distribution solutions for media applications and high data-rate connectivity for enterprise, fixed and mobile telecommunications and government applications.

Intelsat 33e and Intelsat 36 are the company’s 57th and 58th satellites launched by Arianespace since the orbiting of Intelsat 507 in October 1983.

Arianespace has now launched the first two satellites in the Intelsat EpicNG series:

- Intelsat 29e, launched in January 2016, covers the Americas and the North Atlantic.

- Intelsat 33e, the second satellite in this series, will provide broadband coverage of Europe, the Middle East, Africa and the Asia-Pacific, as well as certain media solutions.

The Intelsat 36 satellite will provide media distribution services for the south African and Indian Ocean regions.

Since being founded, Arianespace has launched half of all Intelsat satellites, including half of its current in-orbit fleet of operational satellites.

In 2017, Arianespace will launch two other Intelsat satellites: Intelsat 32e and Intelsat 37e.

A fruitful collaboration with satellite manufacturers Boeing and SSL

Ariane 5 ECA / Intelsat 33e & 36 / Flight VA232 Mission poster

Arianespace and Boeing have been partners since 1987. Intelsat 33e is the 52nd Boeing satellite to be launched by Arianespace, which has four more Boeing satellites in its order book.

Arianespace and SSL have been working together since 1983. With Intelsat 36, Arianespace has now launched 56 satellites based on SSL platforms, and has nine more SSL satellites in its order book, including five to be deployed in GTO.

A strong presence in the United States

Arianespace opened an office in Washington, D.C. in 1986 and has clearly established its position as a major player in the United States.

The launch services provider now has five geostationary (GEO) satellites in its order book for U.S.-based operators, along with 12 geostationary satellites built by American manufacturers.

Arianespace also will deploy telecommunications and Earth observation constellations built in the United States.

Arianespace in the United States

- Present for 30 years in the U.S., via Arianespace, Inc., the Washington, D.C.-based Arianespace subsidiary.

- 87 GEO and 69 non-GEO satellites launched for American operators.

- 177 satellites launched by Arianespace were built by American manufacturers.

- Nearly half of the GEO satellites orbited for American operators have been launched by Arianespace.

Additionally, Arianespace will use an Ariane 5 in October 2018 to launch the James Webb Space Telescope (JWST), developed by NASA in conjunction with the Canadian Space Agency and European Space Agency (ESA).

Intelsat 33e

Intelsat 33e was built by Boeing using a Boeing-702MP platform. Intelsat 33e had a liftoff mass of 6,600 kg., and offers a design life exceeding 15 years. Positioned at 60° East, it is fitted with 249 Ku-band and 20 C-band transponders. Coverage zone: Europe, Middle East, Africa and Asia-Pacific.

Intelsat 36

Intelsat 36 was built by SSL using a 1300 platform. Intelsat 36 had a liftoff mass of 3,253 kg., and offers a design life exceeding 15 years. Positioned at 68.5° East, it is fitted with 10 C-band and 34 Ku-band transponders. Coverage zone: Southern Africa and the Indian Ocean.

The launch at a glance

Shortly after the announcement of the orbital injection of the two satellites on today’s Flight VA232 with Ariane 5, Arianespace Chairman and Chief Executive Officer Stéphane Israël said: “Two more! I would like to extend my warmest thanks to Intelsat for honoring us with their loyalty over the last 30-plus years, and for choosing us for to-day’s first-ever launch of two of their telecom satellites on the same Ariane 5. Following the successful launch of Intelsat 29e in January, we are very proud of having earned their trust. I would also like to thank our two long-standing partners, Boeing and SSL, who built the two Intelsat satellites we launched on this mission. My congratula-tions go to everybody who contributed to this 73rd successful launch in a row of Ariane 5: Airbus Safran Launchers and the entire European launcher industry for the reliability and availability of Ariane 5, which confirms its excep-tional performance improvement with today’s launch; ESA, for its seamless support for the Ariane program; the CNES/CSG, and all companies and staff at the launch base, who continue to support us as we go from success to success; and of course the teams at Arianespace, for their commitment and professionalism, as we mark our sixth successful launch in 2016 and gear up for five more launches during the year.”

About Arianespace

To use space for a better life on earth, Arianespace guarantees access to space transportation services and solu-tions for any type of satellite, commercial as well as institutional, into any orbit. Since 1980, Arianespace has placed more than 500 satellites into orbit with its three launchers, Ariane, Soyuz and Vega, from French Gui-ana in South America, and from Baikonur, Kazakhstan (central Asia). Arianespace is headquartered in Evry, France near Paris, and has a facility at the Guiana Space Center in French Guiana, plus local offices in Washington, D.C., Tokyo and Singapore.

For more information about Arianespace, visit:

Images, Video, Text, Credits: ARIANESPACE/Intelsat/Günter Space Page.

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Planet Found in Habitable Zone Around Nearest Star

ESO - European Southern Observatory logo.

24 August 2016

Pale Red Dot campaign reveals Earth-mass world in orbit around Proxima Centauri

Artist's impression of the planet orbiting Proxima Centauri

Astronomers using ESO telescopes and other facilities have found clear evidence of a planet orbiting the closest star to Earth, Proxima Centauri. The long-sought world, designated Proxima b, orbits its cool red parent star every 11 days and has a temperature suitable for liquid water to exist on its surface. This rocky world is a little more massive than the Earth and is the closest exoplanet to us — and it may also be the closest possible abode for life outside the Solar System. A paper describing this milestone finding will be published in the journal Nature on 25 August 2016.

The location of Proxima Centauri in the southern skies

Just over four light-years from the Solar System lies a red dwarf star that has been named Proxima Centauri as it is the closest star to Earth apart from the Sun. This cool star in the constellation of Centaurus is too faint to be seen with the unaided eye and lies near to the much brighter pair of stars known as Alpha Centauri AB.

Proxima Centauri and its planet compared to the Solar System

During the first half of 2016 Proxima Centauri was regularly observed with the HARPS spectrograph on the ESO 3.6-metre telescope at La Silla in Chile and simultaneously monitored by other telescopes around the world [1]. This was the Pale Red Dot campaign, in which a team of astronomers led by Guillem Anglada-Escudé, from Queen Mary University of London, was looking for the tiny back and forth wobble of the star that would be caused by the gravitational pull of a possible orbiting planet [2].

The motion of Proxima Centauri in 2016, revealing the fingerprints of a planet

As this was a topic with very wide public interest, the progress of the campaign between mid-January and April 2016 was shared publicly as it happened on the Pale Red Dot website and via social media. The reports were accompanied by numerous outreach articles written by specialists around the world.

Artist's impression of the planet orbiting Proxima Centauri

Guillem Anglada-Escudé explains the background to this unique search: “The first hints of a possible planet were spotted back in 2013, but the detection was not convincing. Since then we have worked hard to get further observations off the ground with help from ESO and others. The recent Pale Red Dot campaign has been about two years in the planning.”

The sky around Alpha Centauri and Proxima Centauri (annotated)

The Pale Red Dot data, when combined with earlier observations made at ESO observatories and elsewhere, revealed the clear signal of a truly exciting result. At times Proxima Centauri is approaching Earth at about 5 kilometres per hour — normal human walking pace — and at times receding at the same speed. This regular pattern of changing radial velocities repeats with a period of 11.2 days. Careful analysis of the resulting tiny Doppler shifts showed that they indicated the presence of a planet with a mass at least 1.3 times that of the Earth, orbiting about 7 million kilometres from Proxima Centauri — only 5% of the Earth-Sun distance [3].

Proxima Centauri in the southern constellation of Centaurus

Guillem Anglada-Escudé comments on the excitement of the last few months: "I kept checking the consistency of the signal every single day during the 60 nights of the Pale Red Dot campaign. The first 10 were promising, the first 20 were consistent with expectations, and at 30 days the result was pretty much definitive, so we started drafting the paper!"

Relative Sizes of the Alpha Centauri Components and other Objects (artist’s impression)

Red dwarfs like Proxima Centauri are active stars and can vary in ways that would mimic the presence of a planet. To exclude this possibility the team also monitored the changing brightness of the star very carefully during the campaign using the ASH2 telescope at the San Pedro de Atacama Celestial Explorations Observatory in Chile and the Las Cumbres Observatory telescope network. Radial velocity data taken when the star was flaring were excluded from the final analysis.

The sky around Alpha Centauri and Proxima Centauri

Although Proxima b orbits much closer to its star than Mercury does to the Sun in the Solar System, the star itself is far fainter than the Sun. As a result Proxima b lies well within the habitable zone around the star and has an estimated surface temperature that would allow the presence of liquid water. Despite the temperate orbit of Proxima b, the conditions on the surface may be strongly affected by the ultraviolet and X-ray flares from the star — far more intense than the Earth experiences from the Sun [4].

Artist's impression of the planet orbiting Proxima Centauri (annotated)

Two separate papers discuss the habitability of Proxima b and its climate. They find that the existence of liquid water on the planet today cannot be ruled out and, in such case, it may be present over the surface of the planet only in the sunniest regions, either in an area in the hemisphere of the planet facing the star (synchronous rotation) or in a tropical belt (3:2 resonance rotation). Proxima b's rotation, the strong radiation from its star and the formation history of the planet makes its climate quite different from that of the Earth, and it is unlikely that Proxima b has seasons.

Angular apparent size comparison

This discovery will be the beginning of extensive further observations, both with current instruments [5] and with the next generation of giant telescopes such as the European Extremely Large Telescope (E-ELT). Proxima b will be a prime target for the hunt for evidence of life elsewhere in the Universe. Indeed, the Alpha Centauri system is also the target of humankind’s first attempt to travel to another star system, the StarShot project.

The brilliant southern Milky Way

Guillem Anglada-Escudé concludes: "Many exoplanets have been found and many more will be found, but searching for the closest potential Earth-analogue and succeeding has been the experience of a lifetime for all of us. Many people’s stories and efforts have converged on this discovery. The result is also a tribute to all of them. The search for life on Proxima b comes next..."

The Pale Red Dot Campaign

Artist's impression of the planet orbiting Proxima Centauri

Artist's impression of the planet orbiting Proxima Centauri

A journey to Proxima Centauri and its planet

A fly-through of the Proxima Centauri system

A fly-through of the Proxima Centauri system


[1] Besides data from the recent Pale Red Dot campaign, the paper incorporates contributions from scientists who have been observing Proxima Centauri for many years. These include members of the original UVES/ESO M-dwarf programme (Martin Kürster and Michael Endl), and exoplanet search pioneers such as R. Paul Butler. Public observations from the HARPS/Geneva team obtained over many years were also included.

[2] The name Pale Red Dot reflects Carl Sagan’s famous reference to the Earth as a pale blue dot. As Proxima Centauri is a red dwarf star it will bathe its orbiting planet in a pale red glow.

[3] The detection reported today has been technically possible for the last 10 years. In fact, signals with smaller amplitudes have been detected previously. However, stars are not smooth balls of gas and Proxima Centauri is an active star. The robust detection of Proxima b has only been possible after reaching a detailed understanding of how the star changes on timescales from minutes to a decade, and monitoring its brightness with photometric telescopes.

[4] The actual suitability of this kind of planet to support water and Earth-like life is a matter of intense but mostly theoretical debate. Major concerns that count against the presence of life are related to the closeness of the star. For example gravitational forces probably lock the same side of the planet in perpetual daylight, while the other side is in perpetual night. The planet's atmosphere might also slowly be evaporating or have more complex chemistry than Earth’s due to stronger ultraviolet and X-ray radiation, especially during the first billion years of the star’s life. However, none of the arguments has been proven conclusively and they are unlikely to be settled without direct observational evidence and characterisation of the planet’s atmosphere. Similar factors apply to the planets recently found around TRAPPIST-1.

[5] Some methods to study a planet’s atmosphere depend on it passing in front of its star and the starlight passing through the atmosphere on its way to Earth. Currently there is no evidence that Proxima b transits across the disc of its parent star, and the chances of this happening seem small, but further observations to check this possibility are in progress.

More information:

This research is presented in a paper entitled “A terrestrial planet candidate in a temperate orbit around Proxima Centauri”, by G. Anglada-Escudé et al., to appear in the journal Nature on 25 August 2016.

The team is composed of Guillem Anglada-Escudé (Queen Mary University of London, London, UK), Pedro J. Amado (Instituto de Astrofísica de Andalucía - CSIC, Granada, Spain), John Barnes (Open University, Milton Keynes, UK), Zaira M. Berdiñas (Instituto de Astrofísica de Andalucia - CSIC, Granada, Spain), R. Paul Butler (Carnegie Institution of Washington, Department of Terrestrial Magnetism, Washington, USA), Gavin A. L. Coleman (Queen Mary University of London, London, UK), Ignacio de la Cueva (Astroimagen, Ibiza, Spain), Stefan Dreizler (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany), Michael Endl (The University of Texas at Austin and McDonald Observatory, Austin, Texas, USA), Benjamin Giesers (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany), Sandra V. Jeffers (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany), James S. Jenkins (Universidad de Chile, Santiago, Chile), Hugh R. A. Jones (University of Hertfordshire, Hatfield, UK), Marcin Kiraga (Warsaw University Observatory, Warsaw, Poland), Martin Kürster (Max-Planck-Institut für Astronomie, Heidelberg, Germany), María J. López-González (Instituto de Astrofísica de Andalucía - CSIC, Granada, Spain), Christopher J. Marvin (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany), Nicolás Morales (Instituto de Astrofísica de Andalucía - CSIC, Granada, Spain), Julien Morin (Laboratoire Univers et Particules de Montpellier, Université de Montpellier & CNRS, Montpellier, France), Richard P. Nelson (Queen Mary University of London, London, UK), José L. Ortiz (Instituto de Astrofísica de Andalucía - CSIC, Granada, Spain), Aviv Ofir (Weizmann Institute of Science, Rehovot, Israel), Sijme-Jan Paardekooper (Queen Mary University of London, London, UK), Ansgar Reiners (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany), Eloy Rodriguez (Instituto de Astrofísica de Andalucía - CSIC, Granada, Spain), Cristina Rodriguez-Lopez (Instituto de Astrofísica de Andalucía - CSIC, Granada, Spain), Luis F. Sarmiento (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany), John P. Strachan (Queen Mary University of London, London, UK), Yiannis Tsapras (Astronomisches Rechen-Institut, Heidelberg, Germany), Mikko Tuomi (University of Hertfordshire, Hatfield, UK) and Mathias Zechmeister (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany).

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ESOcast 87: Pale Red Dot Results:

Research paper in Nature:

ESO press conference (01:02:26):

Two new papers on Habitability on Proxima b:

Pale Red Dot blog:

Photos of the VLT:

Photos of HARPS and the ESO 3.6-metre telescope:

Video of the ESO 3.6-metre telescope:

Photos of LCOGT telescopes:

MPIA press release:

LCOGT press release:

University of Hertfordshire press release:

Laboratoire Univers et Particules de Montpellier press release:

Additional images and videos from the PHL @ UPR Arecibo:

University of Texas/McDonald Observatory press release:

Images, Text, Credits: ESO/M. Kornmesser/Y. Beletsky (LCO)/ESO/ESA/NASA/M. Zamani/G. Coleman/G. Anglada-Escudé/Digitized Sky Survey 2/Acknowledgement: Davide De Martin/Mahdi Zamani/IAU and Sky & Telescope/G. Coleman/A. Fujii/Pale Red Dot/Videos: ESO/M. Kornmesser/L. Calçada/Nick Risinger ( @ UPR Arecibo, ESO. Music by Lyford Rome.