samedi 28 mars 2015

PSLV-C27 successfully launches IRNSS-1D satellite

ISRO - PSLV-C27/IRNSS-1D Mission poster.

March 28, 2015

PSLV-C27 successfully launches IRNSS-1D satellite

PSLV-C27 rocket carrying IRNSS-1D satellite launch

India has continued deployment of its IRNSS navigation system Saturday, with the launch of the fourth satellite atop a Polar Satellite Launch Vehicle from the Satish Dhawan Space Centre at Sriharikota. Launched on schedule at 17:19 local time (11:49 UTC), the IRNSS-1D mission marks India’s first orbital launch of the year.

PSLV-C27 - IRNSS - 1D Mission - launched Successfully

PSLV-C27/IRNSS-1D Mission

The fourth satellite of IRNSS Constellation, IRNSS-1D was launched onboard PSLV-C27. The satellite is one among the seven of the IRNSS constellation of satellites slated to be launched to provide navigational services to the region. The satellite is placed in geosynchronous orbit.

IRNSS-1D satellite

The satellite will help augmenting the satellite based navigation system of India which is currently under development. The navigational system so developed will be a regional one targeted towards South Asia. The satellite will provide navigation, tracking and mapping services.
IRNSS satellites constellation

The IRNSS constellation calls for three geostationary satellites and four more in inclined geosynchronous orbits. The geostationary slots, located at 34, 83 and 132 degrees East will each be occupied by a single satellite, while the two inclined stations, at 55 and 111.75 degrees East will each be home to a pair of spacecraft.

For more information about Indian Space Research Organisation (ISRO), visit:

Images, Video, Text, Credits: ISRO/DD News/Gunter Space Page/ Aerospace.


Scars on Mars from 2012 Rover Landing Fade - Usually

NASA - Mars Reconnaissance Orbiter (MRO) logo.

March 28, 2015

Animation above: This sequence of images shows a blast zone where the sky crane from NASA's Curiosity rover mission hit the ground after setting the rover down in August 2012, and how that dark scar's appearance changed over the subsequent 30 months. Image Credit: NASA/JPL-Caltech/Univ. of Arizona.

A series of observations from Mars orbit show how dark blast zones that were created during the August 2012 landing of NASA's Curiosity rover have faded inconsistently.

The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter made the observations on multiple dates from landing to last month. After fading for about two years, the pace of change slowed and some of the scars may have even darkened again.

Figure 1

- Figure 1 is a sequence showing the spacecraft's back shell and parachute. Wind causes changes in the shape of the parachute as well as fading of the dark zone visible around the back shell in initial frames. Image credit: NASA/JPL-Caltech/Univ. of Arizona.

The images track changes in blast zones at four locations caused by different pieces of Curiosity hardware, such as the heat shield and the descent stage. The four series, each with images from five to seven different dates since landing, are available online at:

"Spacecraft like Curiosity create these dark blast zone patterns where bright dust is blown away by the landing," said Ingrid Daubar, a HiRISE team scientist at NASA's Jet Propulsion Laboratory, Pasadena, California, who has used similar blast zones to find fresh meteor impact sites on Mars. "We expected to see them fade as the wind moved the dust around during the months and years after landing, but we've been surprised to see that the rate of change doesn't appear to be consistent."

Figure 2

- The Figure 2 sequence shows where the rover itself landed. Curiosity disappears after the first two of the seven frames because it drove away. Its wheel tracks heading generally east (toward the left) can be seen in subsequent frames, and they also fade over time. Image credit: NASA/JPL-Caltech/Univ. of Arizona.

One purpose for repeated follow-up imaging of Curiosity's landing area has been to check whether scientists could model the fading and predict how long it would take for the scars to disappear. Daubar's work on this aids preparations for NASA's next Mars lander, InSight, on track for launch in March 2016. The InSight mission will deploy a heat probe that will hammer itself a few yards, or meters, deep into the ground to monitor heat coming from the interior of the planet. The brightness of the ground affects temperature below ground, because a dark surface warms in sunshine more than a bright one does.

Figure 3

- Figure 3 is a five-frame sequence of the location where the spacecraft's heat shield hit the ground. Image credit: NASA/JPL-Caltech/Univ. of Arizona.

HiRISE is one of six instruments with which NASA's Mars Reconnaissance Orbiter has been studying Mars since 2006.

NASA's Mars Science Laboratory Project has been using the Curiosity rover to examine ancient Martian environments favorable for microbial life.

With three active NASA Mars orbiters and two Mars rovers, NASA seeks to characterize and understand Mars as a dynamic system, including its present and past environment, climate cycles, geology and biological potential. In parallel on its journey to Mars, NASA is developing the capabilities needed for human missions there.

 Mars Reconnaissance Orbiter (MRO). Image Credits: NASA/JPL-Caltech

The University of Arizona, Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp. of Boulder, Colorado. JPL, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter Project, the Mars Science Laboratory Project and the InSight Project for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, built the orbiter and collaborates with JPL to operate it.

Links for additional info:

About HiRISE:

About NASA's Mars Reconnaissance Orbiter:

About Curiosity and NASA's Mars Science Laboratory Project:

About InSight:

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

Best regards,

vendredi 27 mars 2015

One-Year Crew Welcomed Aboard Space Station

ISS - Expedition 43 Mission patch.

March 28, 2015

Three crew members representing the United States and Russia are on their way to the International Space Station after launching from the Baikonur Cosmodrome in Kazakhstan at 3:42 p.m. EDT Friday (1:42 a.m., March 28 in Baikonur).

Image above: The Soyuz TMA-16M spacecraft is seen as it launches to the International Space Station with Expedition 43's NASA Astronaut Scott Kelly and Russian cosmonauts Mikhail Kornienko and Gennady Padalka of the Russian Federal Space Agency (Roscosmos) onboard Friday, March 27 (Saturday, March 28 Kazakh time) from the Baikonur Cosmodrome in Kazakhstan. Image Credit: NASA/Bill Ingalls.

NASA astronaut Scott Kelly and Russian Federal Space Agency (Roscosmos) cosmonaut Mikhail Kornienko will spend about a year living and working aboard the space station to help scientists better understand how the human body reacts and adapts to the harsh environment of space.

Image above: NASA astronaut Scott Kelly gives a thumbs-up from inside the Soyuz TMA-16M taking him and Expedition 43 crewmates Mikhail Kornienko, and Gennady Padalka of the Russian Federal Space Agency (Roscosmos) to the International Space Station after a successful launch from the Baikonur Cosmodrome in Kazakhstan. Image Credit: NASA.

“Scott Kelly’s mission is critical to advancing the administration’s plan to send humans on a journey to Mars,” said NASA Administrator Charles Bolden. “We’ll gain new, detailed insights on the ways long-duration spaceflight affects the human body.”

Launching with Kelly and Kornienko was cosmonaut Gennady Padalka, who will spend a standard six-month rotation on the station. The trio is scheduled to dock with the station at 9:36 p.m., about six hours after launch.

The arrival of Kelly, Kornienko and Padalka returns the station's crew complement to six. The three will join Expedition 43 commander Terry Virts of NASA, as well as flight engineers Samantha Cristoforetti of ESA (European Space Agency) and Anton Shkaplerov of Roscosmos, who have been aboard the complex since November.

Welcome to the Space Station

Virts, Cristoforetti and Shkaplerov will return home in May. At that time, Padalka will take command of Expedition 44, becoming the first person to command four station crews. Padalka will return in September, while Kelly and Kornienko will remain aboard until March 2016.

The one-year mission will focus on seven key areas of human research. Functional studies will examine crew member performance during and after the 12-month expedition. Behavioral studies will monitor sleep patterns and exercise routines. Visual impairment will be studied by measuring changes in pressure inside the human skull. Metabolic investigations will examine the immune system and effects of stress.

Physical performance will be monitored through exercise examinations. Microbial changes in the crew will be monitored, as well as the human factors associated with how the crew interacts aboard the station. Each of these key elements carries a potential benefit for populations here on Earth, from functional improvements for patients recovering from a long period of bed rest to improving the monitoring of immune functions of people on Earth with altered immunity.

The three crew members of the Soyuz TMA-16M. Image Credit: NASA TV

Data from Kelly and Kornienko’s 342-day expedition will be used to determine whether there are ways to further reduce the risks on future long-duration missions necessary for deep space missions.

In tandem with the one-year mission, Kelly’s identical twin brother, former NASA astronaut Mark Kelly, will participate in a number of comparative genetic studies, including the collection of blood samples as well as psychological and physical tests. This research will compare data from the genetically identical Kelly brothers to identify any subtle changes caused by spaceflight.

The tests will track any degeneration or evolution that occurs in the human body from extended exposure to a microgravity environment. These new twin studies are a multi-faceted national cooperation between universities, corporations and government laboratory expertise.

Space Station Stories: The One Year Mission

Video above: NASA astronaut Scott Kelly and Russian cosmonaut Mikhail Kornienko will spend nearly twelve months conducting important human research studies that will provide new insights into how the human body adjusts to weightlessness, isolation, radiation and stress of long-duration spaceflight. Video Credit: NASA.

Expedition 43 will perform scientific research in several other fields, such as astrophysics and biotechnology. Among the planned experiments are a study of meteors entering Earth’s atmosphere and testing of a new synthetic material that can expand and contract like human muscle tissue. The crew members also are scheduled to greet a host of cargo spacecraft during their mission, including the sixth SpaceX commercial resupply flight and a Russian Progress resupply mission. Each flight will carry several tons of food, fuel, supplies and research. No spacewalks are planned during Expedition 43.

The International Space Station is a convergence of science, technology and human innovation that demonstrates new technologies and makes research breakthroughs that are not possible on Earth. The space station has been continuously occupied since November 2000. In this time, it has received more than 200 visitors and a variety of international and commercial spacecraft. The space station remains the springboard to NASA's next giant leap in exploration.

For NASA TV streaming video, downlink and scheduling information, visit:

For more information about this mission to the space station, visit:

For more information about the research on this mission, visit:

To follow activities on orbit, visit the space station Facebook page at:

Follow the crew members and the station on Twitter at: and

For more information about the International Space Station and its crews, visit:

Images (mentioned), Video, Text, Credits: NASA/Stephanie Schierholz/NASA TV/Johnson Space Center/Dan Huot.

Best regards,

Soyuz With One-Year Crew Docks With Station

ROSCOSMOS - Soyuz TMA-16M Mission patch.

March 27, 2015

The Soyuz TMA-16M vehicle docked to the International Space Station at 9:33 p.m. EDT, over the western coast of Colombia.

Image above: There are now two Progress resupply space freighters and two Soyuz crew vehicles at the International Space Station.

Aboard the space station, Expedition 43 Commander Terry Virts of NASA, Anton Shkaplerov of the Russian Federal Space Agency (Roscosmos) and Samantha Cristoforetti of ESA (European Space Agency) will welcome Soyuz crew members Scott Kelly of NASA, and Mikhail Kornienko and Gennady Padalka of Roscosmos when the hatches between the two spacecraft are opened.

One-Year Crew Docks to ISS

NASA astronaut Scott Kelly and Mikhail Kornienko and Gennady Padalka of the Russian Federal Space Agency (Roscosmos) joined their Expedition 43 crewmates when the hatches between the Soyuz TMA-16M spacecraft and the International Space Station opened at 11:33 p.m. EDT Friday, March 27. Kelly and Kornienko will spend about a year on the space station to better understand how the human body reacts and adapts to the harsh environment of space.

The Soyuz crew will join Expedition 43 Commander Terry Virts of NASA, Anton Shkaplerov of Roscosmos and Samantha Cristoforetti of ESA (European Space Agency). Virts, Shkaplerov and Cristoforetti have lived aboard the space station since November.

To join the online conversation about the International Space Station and the one-year mission on Twitter, follow the hashtag #YearinSpace.

For more information about the International Space Station and its crews, visit:

Image, Video, Text, Credits: NASA / NASA TV.


Arianespace expands Europe’s Galileo global navigation satellite system with its latest Soyuz success

Arianespace / ESA - Soyuz Flight VS11 Galileo FOC launch poster.

March 27, 2015

Image above: Flight VS11 was the 11th Soyuz liftoff performed from French Guiana since this vehicle’s 2011 introduction at the Spaceport.

With tonight’s Soyuz success that lofted two Galileo satellites from French Guiana, Arianespace once again has delivered on its primary mission to support European governments and institutions with independent, reliable and available access to space.

Lifting off from the Spaceport at precisely 6:46:18 p.m. local time, the medium-lift Soyuz performed a flight of nearly 3 hours and 48 minutes to deploy “Adam” and “Anastasia” – which are the third and fourth Full Operational Capability (FOC) spacecraft for Europe’s Galileo global navigation satellite system.

Soyuz lifts off from French Guiana with two Galileo FOC spacecraft

After an initial powered phase of Soyuz’ three lower stages, the launch included two burns of the Fregat upper stage – separated by a three-hour-plus ballistic phase – to place the two 700-kg.-class satellites at their targeted deployment point. Total payload lift performance for the flight was estimated at 1,597 kg.  on a mission to a circular medium-Earth orbit.

At full capability, the Galileo program will provide a European-operated navigation system to deliver highly accurate global positioning services through a satellite constellation in medium-Earth orbit, along with its associated ground infrastructure.

Galileo’s FOC phase – during which the network’s complete operational and ground infrastructure will be deployed – is being managed and funded by the European Commission, with the European Space Agency delegated as the design and procurement agent on the Commission’s behalf. Adam and Anastasia were built by OHB System, with Surrey Satellite Technology Ltd. supplying their navigation payloads.

The Galileo constellation satellite

The on-target Soyuz launch of Adam and Anastasia followed by one day the 35th anniversary of Arianespace’s creation in 1980, and it underscores the company’s readiness to reinvent itself and take up the challenge of delivering a service that continues to match customers’ requirements.

Flight VS11 was Arianespace’s second mission in 2015 with a member of its complete launcher family – which also includes the heavyweight Ariane 5 and light-lift Vega. It follows the Vega flight on February 11 that lofted Europe’s Intermediate eXperimental Vehicle (IXV), and puts the company on track to match its 2014 cadence with 11 total launches planned this year from the Spaceport, based on the availability of payloads scheduled for these missions.

Related links:

The European Commission website – Galileo:

The European Space Agency website – Galileo:

For more information about Arianespace, visit:

Images, Video, Text, Credits: Arianespace / Arianespace TV / Aerospace / ESA, P. Carril.

Best regards,

Soyuz Safely in Orbit, Year in Space Begins

ROSCOSMOS - Soyuz TMA-16M Mission patch.

March 27, 2015

Images above: The Soyuz TMA-16M rocket launches on time from the Baikonur Cosmodrome in Kazakhstan to the International Space Station. Image Credit: NASA.

The Soyuz TMA-16M launched from the Baikonur Cosmodrome in Kazakhstan to the International Space Station at 3:42 p.m. EDT (1:42 a.m. on March 28 Baikonur time). Scott Kelly of NASA, Mikhail Kornienko and Gennady Padalka of the Russian Federal Space Agency (Roscosmos) now are safely in orbit.

One-Year Crew Launches to the ISS

NASA TV coverage continues at

Kelly, Kornienko and Padalka will dock with the station’s Poisk module at 9:36 p.m. NASA Television coverage of the docking will begin at 8:45 p.m. Welcoming them aboard will be the current station residents, Expedition 43 Commander Terry Virts of NASA, Anton Shkaplerov of Roscosmos and Samantha Cristoforetti of ESA (European Space Agency). NASA TV coverage of the hatch opening and welcome ceremony begins at 10:45 p.m.

 Boarding the Soyuz Spacecraft on Launch Day

Image above: Expedition 43 Russian cosmonaut Mikhail Kornienko of the Russian Federal Space Agency (Roscosmos), top, NASA astronaut Scott Kelly, center, and Russian cosmonaut Gennady Padalka of Roscosmos wave farewell as they board the Soyuz TMA-16M spacecraft ahead of their launch to the International Space Station, Friday, March 27, 2015 in Baikonur, Kazakhstan.

Virts, Shkaplerov and Cristoforetti arrived at the space station in November aboard their Soyuz TMA-15M spacecraft and will remain aboard until May 14.

For more information about the International Space Station and its crews, visit:

Images (mentioned), Video, Text, Credits: NASA / NASA TV.


JAXA H-2A rocket launches IGS Optical 5 spy satellite

JAXA logo.

27 March 2015

Owned and operated by the Japanese government, the reconnaissance spacecraft lifted off at 01:21 GMT Thursday (9:21 p.m. EDT Wednesday) from the Tanegashima Space Center situated on an island in southwestern Japan, where the launch occurred at 10:21 a.m. local time.

Japan’s H-2A rocket launches a spy satellite

The satellite rocketed into space aboard Japan’s H-2A rocket, which steered south from Tanegashima to deploy its payload into polar orbit. The launcher aimed to release the satellite in an orbit about 300 miles above Earth.

The H-2A rocket’s hydrogen-fueled first and second stage engines apparently functioned as designed to put the Earth-viewing satellite into orbit. This launch marked the 28th flight of Japan’s H-2A rocket since 2001.

 Japanese Rocket Launches IGS Optical-5 Payload Into Orbit

The IGS program was initiated by Japan following North Korea’s attempted launch of the Kwangmyŏngsŏng-1 satellite in August 1998; a launch which overflew Japan and raised concerns about North Korea’s ability to develop a rocket capable of attacking Japan.

IGS Optical satellite

Yesterday launch carried the first third-generation spacecraft for the series, Optical 5. Taking advantage of systems demonstrated by 2013’s prototype mission, the Optical 5 satellite will be used to image the Earth’s surface in high resolution. The prototype was reported to have had a ground resolution of approximately 40 centimeters (16 in).

For more information about Japan Aerospace Exploration Agency (JAXA), visit:

Images, Video, Text, Credits: JAXA/P-island & S. Matsuura/ Aerospace.

Best regards,

Roscosmos Dnepr rocket launches Kompsat-3A mission

ROSCOSMOS logo / KARI - Korea Aerospace Research Institute seal.

27 March 2015

Russian Dnepr rocket launch. Image Credit: Roscosmos

International Space Company (ISC) Kosmotras has launched its Russian Dnepr rocket from Dombarovsky on Wednesday March 25, 2015, carrying the Kompsat-3A satellite for the Korea Aerospace Research Institute (KARI). The launch – which nearly fell foul of a proposed shutdown of Dnepr utilization – was reported to be on schedule at 22:08 UTC on March 25, 2015.

Dnepr Delivers Satellite

Kompsat-3A will be a sister spacecraft to the previously launched Kompsat-3 (Arirang-3), both of which were developed by the Korea Aerospace Research Institute (KARI).

The goal of the KOMPSAT-3 project is to develop and mature the hardware using the technology obtained through the KOMPSAT-1 project and the KOMPSAT-2 project.

Artist's concept of the Kompsat 3A satellite. Image Credit: KARI

It aims to meet Korean satellite demand and form a technology infrastructure that will “make inroads into the world space industry at a stage when the industry is improving the capability to develop and design highly advanced remote sensing satellites,” according to KARI.

Kompsat-3 is operating at an altitude of 685 km in a sun-synchronous orbit using a payload capable of submeter class resolution.

For more information about Korea Aerospace Research Institute (KARI), visit:

Images (mentioned), Video, Text, Credits: ROSCOSMOS/KARI/ Aerospace.


United Launch Alliance Successfully Launches Second Mission in Less than Two Weeks

ULA - Delta IV / GPS IIF-9 launch poster.

27 March 2015

On March 25, 2015 – A United Launch Alliance (ULA) Delta IV rocket successfully launched the ninth Global Positioning System (GPS) IIF satellite for the U.S. Air Force at 2:36 p.m. EDT today from Space Launch Complex-37. This is ULA’s fourth launch in 2015 and the 95th successful launch since the company was formed in December 2006.

“Congratulations to the Air Force and all of our mission partners on today’s successful launch of GPS IIF-9! The ULA team is privileged to work with this world-class U.S. government and contractor mission team, and we are proud to contribute to the GPS capabilities that were delivered to orbit today,” said Jim Sponnick, ULA vice president, Atlas and Delta Programs.“ This entire team is focused on 100 percent mission success, one launch at a time, and also providing on-time launches to meet our customer’s mission needs.”

Delta IV GPS IIF-9 Launch Highlights

This mission was launched aboard a Delta IV Medium-plus (4,2) configuration Evolved Expendable Launch Vehicle (EELV) using a single ULA common booster core powered by an Aerojet Rocketdyne RS-68 main engine, along with two Orbital ATK GEM-60 solid rocket motors. The upper stage was powered by an Aerojet Rocketdyne RL10B-2 engine with the satellite encapsulated in a four-meter-diameter composite payload fairing.

GPS IIF-9 is the ninth in a series of next generation GPS satellites and will join the GPS worldwide timing and navigation system utilizing 24 satellites in six different planes, with a minimum of four satellites per plane positioned in orbit approximately 11,000 miles above the Earth’s surface. The GPS IIF series provides improved accuracy and enhanced performance for GPS users.

ULA's next launch is the Atlas V AFSPC-5 mission for the United States Air Force, scheduled for May 6 from Space Launch Complex-41 from Cape Canaveral Air Force Station, Florida.

Global Positioning System (GPS) IIF satellite

The EELV program was established by the United States Air Force to provide assured access to space for Department of Defense and other government payloads. The commercially developed EELV program supports the full range of government mission requirements, while delivering on schedule and providing significant cost savings over the heritage launch systems.

With more than a century of combined heritage, United Launch Alliance is the nation’s most experienced and reliable launch service provider. ULA has successfully delivered more than 90 satellites to orbit that provide critical capabilities for troops in the field, aid meteorologists in tracking severe weather, enable personal device-based GPS navigation and unlock the mysteries of our solar system.

For more information on ULA, visit the ULA website at Join the conversation at, and

Image, Video, Text, Credits: ULA / USAF.


jeudi 26 mars 2015

Astronomers Upgrade Their Cosmic Light Bulbs

NASA - GALEX Mission patch.

March 26, 2015

The brilliant explosions of dead stars have been used for years to illuminate the far-flung reaches of our cosmos. The explosions, called Type Ia supernovae, allow astronomers to measure the distances to galaxies and measure the ever-increasing rate at which our universe is stretching apart.

But these tools aren't perfect. In the cosmic hardware store of our universe, improvements are ongoing. In a new report, appearing March 27 in the journal Science, astronomers identify the best, top-of-the-line Type Ia supernovae for measuring cosmic distances, pushing other, more clunky tools to the back of the shelf.

Using archived data from NASA's Galaxy Evolution Explorer (GALEX), scientists show that a particular class of Type Ia supernovae that occur near youthful stars can improve these measurements with a precision of more than two times that achieved before.

Image above: A new study analyzes several sites where dead stars once exploded. Image credit: SDSS.

"We have discovered a population of Type Ia supernovae whose light output depends very precisely on how quickly they fade, making it possible to measure very exact distances to them," said Patrick Kelly of the University of California, Berkeley, lead author of the new study. "These supernovae are found close to populations of bright, hot young stars."

The findings will help light the way to understanding dark energy, one of the greatest mysteries in the field of cosmology, the study of the origin and development of the universe. Dark energy is the leading culprit behind the baffling acceleration of our cosmos, a phenomenon discovered in 1998. The acceleration was uncovered when astronomers observed that galaxies are pulling away from each other at increasing speeds.

The key to measuring this acceleration -- and thus the nature of dark energy -- lies with Type Ia supernovae, which work much like light bulbs strung across space. Imagine lining up 60-watt light bulbs across a field and standing at one end. The farthest light bulb wouldn't appear as bright as the closest one due to its distance. Since you know how bright the light bulb inherently is, you can use the extent of its dimming to figure out the distance.

Type Ia supernovae, also referred to as "standard candles," work in a similar way because they consistently shine with about the same amount of light. While the process that leads to these explosions is still not clear, they occur when the burnt-out core of a star, called a white dwarf, blasts apart in a regular way, briefly lighting up the host galaxy.

However, the explosions aren't always precisely uniform. They can differ considerably depending on various factors, which appear to be connected to the environments and histories of the exploding stars. It's as if our 60-watt bulbs sometimes give off 55 watts of light, skewing distance measurements.

Kelly and his team investigated the reliability of these tools by analyzing the surroundings of nearly 100 previous Type Ia explosions. They used data from GALEX, which detects ultraviolet light. Populations of hot, young stars in galaxies will shine brightly with ultraviolet light, so GALEX can distinguish between young and older star-forming communities.

The results showed that the Type Ia supernovae affiliated with the hot, young stars were significantly more reliable at indicating distances than their counterparts.

"These explosions are likely the result of youthful white dwarfs," said Kelly.

 Galaxy Evolution Explorer (GALEX). Image Credit: NASA

By focusing on this particular brand of Type Ia tools, astronomers will be able to, in the future, make even sharper measurements of the size and scale of our universe. According to the science team, this class of tools could work at distances up to six billion light-years away, and perhaps farther.

"GALEX surveyed the entire sky, allowing past and future eruptions of these high-quality standard candles to be identified easily," said Don Neill, a member of the GALEX team at the California Institute of Technology in Pasadena, not affiliated with the study. "Any improvement in the standard candles will have a direct impact on theories of dark energy, allowing us to home in on this mysterious force propelling the acceleration of the universe."

Caltech led the Galaxy Evolution Explorer mission and was responsible for science operations and data analysis. The mission ended in 2013 after more than a decade of scanning the skies in ultraviolet light. NASA's Jet Propulsion Laboratory in Pasadena, California, managed the mission and built the science instrument. The mission was developed under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Maryland. Researchers sponsored by Yonsei University in South Korea and the Centre National d'Etudes Spatiales (CNES) in France collaborated on this mission. ?

Graphics and additional information about the Galaxy Evolution Explorer are online at: and

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

Best regards,

Dark matter even darker than once thought

ESA - Hubble Space Telescope patch.

26 March 2015

Hubble explores the dark side of cosmic collisions

Collage of six cluster collisions with dark matter maps

Astronomers using observations from the NASA/ESA Hubble Space Telescope and NASA’s Chandra X-ray Observatory have studied how dark matter in clusters of galaxies behaves when the clusters collide. The results, published in the journal Science on 27 March 2015, show that dark matter interacts with itself even less than previously thought, and narrows down the options for what this mysterious substance might be.

Galaxy cluster Abell 370 with dark matter map

Dark matter is a giant question mark looming over our knowledge of the Universe. There is more dark matter in the Universe than visible matter, but it is extremely elusive; it does not reflect, absorb or emit light, making it invisible. Because of this, it is only known to exist via its gravitational effects on the visible Universe (see e.g. heic1215a).

Galaxy cluster Abell 2744 with dark matter map

To learn more about this mysterious substance, researchers can study it in a way similar to experiments on visible matter — by watching what happens when it bumps into things [1]. For this reason, researchers look at vast collections of galaxies, called galaxy clusters, where collisions involving dark matter happen naturally and where it exists in vast enough quantities to see the effects of collisions [2].

Galaxy cluster MACS J0152.5-2852 with dark matter map

Galaxies are made of three main ingredients: stars, clouds of gas and dark matter. During collisions, the clouds of gas spread throughout the galaxies crash into each other and slow down or stop. The stars are much less affected by the drag from the gas [3] and, because of the huge gaps between them, do not have a slowing effect on each other — though if two stars did collide the frictional forces would be huge.

Galaxy cluster MACS J0416.1–2403 with dark matter map

"We know how gas and stars react to these cosmic crashes and where they emerge from the wreckage. Comparing how dark matter behaves can help us to narrow down what it actually is," explains David Harvey of the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland, lead author of a new study.

Galaxy cluster MACS J0717.5+3745 with dark matter map

Harvey and his team used data from the NASA/ESA Hubble Space Telescope and NASA's Chandra X-ray Observatory to study 72 large cluster collisions. The collisions happened at different times, and are seen from different angles — some from the side, and others head-on [4].

The team found that, like the stars, the dark matter continued straight through the violent collisions without slowing down. However, unlike in the case of the stars, this is not because the dark matter is far away from other dark matter during the collisions. The leading theory is that dark matter is spread evenly throughout the galaxy clusters so dark matter particles frequently get very close to each other. The reason the dark matter doesn't slow down is because not only does it not interact with visible particles, it also interacts even less with other dark matter than previously thought.

Galaxy cluster ZwCl 1358+62 with dark matter map

"A previous study had seen similar behaviour in the Bullet Cluster," says team member Richard Massey of Durham University, UK. "But it's difficult to interpret what you're seeing if you have just one example. Each collision takes hundreds of millions of years, so in a human lifetime we only get to see one freeze-frame from a single camera angle. Now that we have studied so many more collisions, we can start to piece together the full movie and better understand what is going on."

By finding that dark matter interacts with itself even less than previously thought, the team have successfully narrowed down the properties of dark matter. Particle physics theorists have to keep looking, but they now have a smaller set of unknowns to work with when building their models[5].

Collage of six cluster collisions, with dark-matter maps and X-ray data

Dark matter could potentially have rich and complex properties, and there are still several other types of interaction to study. These latest results rule out interactions that create a strong frictional force, causing dark matter to slow down during collisions. Other possible interactions could make dark matter particles bounce off each other like billiard balls, causing dark matter to be thrown out of collisions or for dark matter blobs to change shape. The team will be studying these next.

To further increase the number of collisions that can be studied, the team are also looking to study collisions involving individual galaxies, which are much more common.

Fade through of galaxy cluster images

"There are still several viable candidates for dark matter, so the game is not over, but we are getting nearer to an answer," concludes Harvey. "These 'Astronomically Large' particle colliders are finally letting us glimpse the dark world all around us but just out of reach."


[1] On Earth scientists use particle accelerators to find out more about the properties of different particles. Physicists can investigate what substances are made of by accelerating particles into a collision, and examining the properties and trajectory of the resulting debris.

[2] Clusters of galaxies are a swarm of galaxies permeated by a sea of hot X-ray emitting ionised hydrogen gas that is all embedded in a massive cloud of dark matter. It is the interactions of these, the most massive structures in the Universe that are observed to test dark matter’s properties.

[3] The gas-gas interaction in cluster collisions is very strong, while the gas-star drag is weak. In a similar way to a soap bubble and a bullet in the wind where the bubble would interact a great deal more with the wind than the bullet.

[4] To find out where the dark matter was located in the cluster the researchers studied the light from galaxies behind the cluster whose light had been magnified and distorted by the mass in the cluster. Because they have a good idea of the visible mass in the cluster, the amount the light is distorted tells them how much dark matter there is in a region.

[5] A favoured theory is that dark matter might be constituted of "supersymmetric" particles. Supersymmetry is a theory in which all particles in our Standard Model — electrons, protons, neutrons, and so on — have a more massive "supersymmetric" partner. While there has been no experimental confirmation for supersymmetry as yet, the theory would solve a few of the gaps in our current thinking. One of supersymmetry's proposed particles would be stable, electrically neutral, and only interact weakly with the common particles of the Standard Model — all the properties required to explain dark matter.

Notes for editors:

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

The research paper, entitled "The non-gravitational interactions of dark matter in colliding galaxy clusters", will be published in the journal Science on 27 March 2015.

The international team of astronomers in this study consists of D. Harvey (École Polytechnique Fédérale de Lausanne, Switzerland; University of Edinburgh, UK), R. Massey (Durham University, UK), T. Kitching (University College London, UK), A. Taylor (University of Edinburgh, UK), and E. Tittley (University of Edinburgh, UK).


Images of Hubble:

Link to science paper:

Images, Text, Video, Credits: NASA, ESA, D. Harvey (École Polytechnique Fédérale de Lausanne, Switzerland), R. Massey (Durham University, UK), the Hubble SM4 ERO Team, ST-ECF, ESO, D. Coe (STScI), J. Merten (Heidelberg/Bologna), HST Frontier Fields, Harald Ebeling(University of Hawaii at Manoa), Jean-Paul Kneib (LAM)and Johan Richard (Caltech, USA),T. Kitching (University College London, UK), and A. Taylor and E. Tittley (University of Edinburgh, UK.


Scuttling satellites to save space

ESA - Clean Space Programme logo.

26 March 2015

It takes a lot of ingenuity – not to mention a massive quantity of sheer force – to get satellites into orbit. Now space engineers are applying comparable ingenuity to the challenge of getting their missions out of there, too.

ESA, working closely with Europe’s satellite builders, will ask industry for new designs to help remove satellites from orbit at the end of their working lives, as well as ‘passivating’ them – making them safer for neighbouring missions.

Solar sail could be used for deorbiting satellites

The selected concepts will be evaluated in ESA’s Concurrent Design Facility at the Agency’s ESTEC technical centre in Noordwijk, the Netherlands. This interlinked multimedia facility allows a large number of different specialists to work on the same software models at once.

The aim is to develop common approaches that can be used by upcoming satellites from all of Europe’s main companies.

Ultimately, space is a finite resource – including the space closest to our world, the low-orbit realm extending up to 2000 km. Highly prized for Earth observation missions and some types of telecom satellites, low orbit has grown increasingly crowded.

The real problem comes not from working missions but derelict ones, abandoned in place after the end of operations.

Left to tumble uncontrolled, they not only pose a collision risk but may also explode, as leftover fuel or batteries overheat, in turn spawning clouds of secondary debris.

CleanSat workshop

In reaction, international regulations governing ‘space debris mitigation’ have been devised. These have been adopted by ESA among many other global space agencies and codified into French law, and are well on the way to becoming commercial standards, too.

In short, these regulations demand that satellites should be removed from busy low orbits within 25 years of their end of life, they should be fully passivated to minimise their risk of fragmenting, and their reentries should pose a minimal risk to people on the ground.

“Space industry is facing up to the problem of achieving compliance with mitigation regulations, while minimising any impact on the cost and effectiveness of their missions,” explains Luisa Innocenti, heading ESA’s Clean Space initiative.

“To assist them, ESA’s new CleanSat initiative is now seeking to develop modular deorbit systems and techniques with the potential to be adopted in common by all Europe’s satellite builders.”

Deorbit sail concepts

Satellites under about 500 km altitude should typically deorbit within the 25 year limit through drag from the top of the atmosphere. Anything placed higher up in space will need assistance to come down.

Key mitigation systems under discussion included compact solid rocket boosters – either to despatch satellites down or else up into less-trafficked ‘graveyard orbits’ – as well as solar sails and drag-augmentation devices to push satellites down faster.

Next month will see an opportunity for companies and institutes to propose ideas for future low-orbit satellite platforms.

 Luisa Innocenti

“Europe’s satellite builders – Airbus Defence and Space, OHB and Thales Alenia Space – are providing inputs into the selection,” adds Luisa. “Smaller satellite builders including Deimos, QinetiQ Space and Surrey Satellite Technology Ltd are also being consulted.

“A short list of around 25 mitigation methods will be finalised, followed up by work to create detailed workplans, which will then be presented to next year’s ESA Ministerial Council for approval.”

Related links:

Space Debris Office:

Space Debris Story 2013:

CleanSat: new satellite technologies for cleaner low orbits:

Technical day on deorbiting strategies and CleanSat workshop:

Images, Text, Credits: ESA/Anneke Le Floc'h/NASA.

Best regards,

Best View Yet of Dusty Cloud Passing Galactic Centre Black Hole

ESO - European Southern Observatory logo.

26 March 2015

VLT observations confirm that G2 survived close approach and is a compact object

The dusty cloud G2 passes the supermassive black hole at the centre of the Milky Way

The best observations so far of the dusty gas cloud G2 confirm that it made its closest approach to the supermassive black hole at the centre of the Milky Way in May 2014 and has survived the experience. The new result from ESO’s Very Large Telescope shows that the object appears not to have been significantly stretched and that it is very compact. It is most likely to be a young star with a massive core that is still accreting material. The black hole itself has not yet shown any increase in activity.

A supermassive black hole with a mass four million times that of the Sun lies at the heart of the Milky Way galaxy. It is orbited by a small group of bright stars and, in addition, an enigmatic dusty cloud, known as G2, has been tracked on its fall towards the black hole over the last few years. Closest approach, known as peribothron, was predicted to be in May 2014.

The great tidal forces in this region of very strong gravity were expected to tear the cloud apart and disperse it along its orbit. Some of this material would feed the black hole and lead to sudden flaring and other evidence of the monster enjoying a rare meal. To study these unique events, the region at the galactic centre has been very carefully observed over the last few years by many teams using large telescopes around the world.

The dusty cloud G2 passes the supermassive black hole at the centre of the Milky Way (annotated)

A team led by Andreas Eckart (University of Cologne, Germany) has observed the region using ESO’s Very Large Telescope (VLT) [1] over many years, including new observations during the critical period from February to September 2014, just before and after the peribothron event in May 2014. These new observations are consistent with earlier ones made using the Keck Telescope on Hawaii [2].

The images of infrared light coming from glowing hydrogen show that the cloud was compact both before and after its closest approach, as it swung around the black hole.

As well as providing very sharp images, the SINFONI instrument on the VLT also splits the light into its component infrared colours and hence allows the velocity of the cloud to be estimated [3]. Before closest approach, the cloud was found to be travelling away from the Earth at about ten million kilometres/hour and, after swinging around the black hole, it was measured to be approaching the Earth at about twelve million kilometres/hour.

Florian Peissker, a PhD student at the University of Cologne in Germany, who did much of the observing, says: “Being at the telescope and seeing the data arriving in real time was a fascinating experience,” and Monica Valencia-S., a post-doctoral researcher also at the University of Cologne, who then worked on the challenging data processing adds: “It was amazing to see that the glow from the dusty cloud stayed compact before and after the close approach to the black hole.”

Although earlier observations had suggested that the G2 object was being stretched, the new observations did not show evidence that the cloud had become significantly smeared out, either by becoming visibly extended, or by showing a larger spread of velocities.

The dusty cloud G2 passes the supermassive black hole at the centre of the Milky Way

In addition to the observations with the SINFONI instrument the team has also made a long series of measurements of the polarisation of the light coming from the supermassive black hole region using the NACO instrument on the VLT. These, the best such observations so far, reveal that the behaviour of the material being accreted onto the black hole is very stable, and — so far — has not been disrupted by the arrival of material from the G2 cloud.

The resilience of the dusty cloud to the extreme gravitational tidal effects so close to the black hole strongly suggest that it surrounds a dense object with a massive core, rather than being a free-floating cloud. This is also supported by the lack, so far, of evidence that the central monster is being fed with material, which would lead to flaring and increased activity.

Andreas Eckart sums up the new results: “We looked at all the recent data and in particular the period in 2014 when the closest approach to the black hole took place. We cannot confirm any significant stretching of the source. It certainly does not behave like a coreless dust cloud. We think it must be a dust-shrouded young star.”


[1] These are very difficult observations as the region is hidden behind thick dust clouds, requiring observations in infrared light. And, in addition, the events occur very close to the black hole, requiring adaptive optics to get sharp enough images. The team used the SINFONI instrument on ESO’s Very Large Telescope and also monitored the behaviour of the central black hole region in polarised light using the NACO instrument.

[2] The VLT observations are both sharper (because they are made at shorter wavelengths) and also have additional measurements of velocity from SINFONI and polarisation measurement using the NACO instrument.

[3] Because the dusty cloud is moving relative to Earth — away from Earth before closest approach to the black hole and towards Earth afterwards — the Doppler shift changes the observed wavelength of light. These changes in wavelength can be measured using a sensitive spectrograph such as the SINFONI instrument on the VLT. It can also be used to measure the spread of velocities of the material, which would be expected if the cloud was extended along its orbit to a significant extent, as had previously been reported.

More information:

This research was presented in a paper “Monitoring the Dusty S-Cluster Object (DSO/G2) on its Orbit towards the Galactic Center Black Hole” by M. Valencia-S. et al. in the journal Astrophysical Journal Letters.

The team is composed of M. Valencia-S. (Physikalisches Institut der Universität zu Köln, Germany), A. Eckart (Universität zu Köln; Max-Planck-Institut für Radioastronomie, Bonn, Germany [MPIfR]), M. Zajacek (Universität zu Köln; MPIfR; Astronomical Institute of the Academy of Sciences Prague, Czech Republic), F. Peissker (Universität zu Köln), M. Parsa (Universität zu Köln), N. Grosso (Observatoire Astronomique de Strasbourg, France), E. Mossoux (Observatoire Astronomique de Strasbourg), D. Porquet (Observatoire Astronomique de Strasbourg), B. Jalali (Universität zu Köln), V. Karas (Astronomical Institute of the Academy of Sciences Prague), S. Yazici (Universität zu Köln), B. Shahzamanian (Universität zu Köln), N. Sabha (Universität zu Köln), R. Saalfeld (Universität zu Köln), S. Smajic (Universität zu Köln), R. Grellmann (Universität zu Köln), L. Moser (Universität zu Köln), M. Horrobin (Universität zu Köln), A. Borkar (Universität zu Köln), M. García-Marín (Universität zu Köln), M. Dovciak (Astronomical Institute of the Academy of Sciences Prague), D. Kunneriath (Astronomical Institute of the Academy of Sciences Prague), G. D. Karssen (Universität zu Köln), M. Bursa (Astronomical Institute of the Academy of Sciences Prague), C. Straubmeier (Universität zu Köln) and H. Bushouse (Space Telescope Science Institute, Baltimore, Maryland, USA).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.


Research paper:

Photos of the VLT:

ESO’s Very Large Telescope (VLT):

Images, Video, Text, Credits: ESO/A. Eckart.