vendredi 20 mai 2011

First Spacewalk Complete; Focused Inspection to Proceed

NASA - STS-134 Mission patch.

Sat, 21 May 2011

Endeavour astronauts completed a 6-hour, 19-minute spacewalk at the International Space Station Friday, retrieving materials experiments and installing another, and installing an antenna.

STS-134 Daily Mission Recap - Flight Day 5
Mission Specialists Andrew Feustel and Greg Chamitoff also installed a light on a station handcart, set up equipment for adding ammonia to a cooling loop and installed a cover on a rotary joint for solar arrays.

An issue with a carbon dioxide level sensor in Chamitoff’s suit caused replanning of the later part of the spacewalk. Removal of a micro meteoroid debris shield to access some cable connection points and to hookup some of the cables was put on hold to ensure Chamitoff would be back in the airlock early. The spacewalk ended at 9:29 a.m. EDT.

The Mission Management Team decided to proceed with a focused inspection of one damage site on Endeavour’s underside Saturday morning. The location is between the right main landing gear door and the External Tank disconnect door.

The rest of Endeavour’s heat shield has been cleared for entry from ascent debris damage.

Image above: Mission Specialist Drew Feustel is seen in this view from the helmet camera of Mission Specialist Greg Chamitoff as they conduct the first spacewalk of the STS-134 mission. Photo credit: NASA TV.

The crew members for space shuttle Endeavour's STS-134 mission are Commander Mark Kelly, Pilot Gregory H. Johnson and Mission Specialists Michael Fincke, Greg Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori.

Image above: Astronaut Drew Feustel works in the vacuum of space during the first of four spacewalks during the STS-134 mission of Space Shuttle Endeavour to the International Space Station. Credit: NASA TV.

During the 16-day mission, Endeavour and its crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre.

NASA's web coverage of STS-134 includes mission information, a press kit, interactive features, news conference images, graphics and videos. Mission coverage, including the latest NASA Television schedule, is available on the main space shuttle website at:

NASA is providing continuous television and Internet coverage of the mission. NASA TV features live mission events, daily status news conferences and 24-hour commentary. For NASA TV streaming video, downlink and schedule information, visit:

Images, Video, Text, Credit: NASA / NASA TV.


Radio Telescopes Capture Best-Ever Snapshot Of Black Hole Jets


NASA - Fermi Gamma-ray Space Telescope logo / TANAMI Project array logo.

May 20, 2011

Video above: Centaurus A is a giant elliptical active galaxy 12 million light-years away. At its heart lies a black hole with a mass of 55 million suns. Now, the TANAMI project has provided the best-ever image of particle jets powered by the black hole, revealing features as small as 15 light-days across. The jets feed vast lobes of radio-emitting gas that reach far beyond the visible galaxy.

An international team, including NASA-funded researchers, using radio telescopes located throughout the Southern Hemisphere has produced the most detailed image of particle jets erupting from a supermassive black hole in a nearby galaxy.

"These jets arise as infalling matter approaches the black hole, but we don't yet know the details of how they form and maintain themselves," said Cornelia Mueller, the study's lead author and a doctoral student at the University of Erlangen-Nuremberg in Germany.

Image above: Merging X-ray data (blue) from NASA’s Chandra X-ray Observatory with microwave (orange) and visible images reveals the jets and radio-emitting lobes emanating from Centaurus A's central black hole. Credit: ESO/WFI (visible); MPIfR/ESO/APEX/A.Weiss et al. (microwave); NASA/CXC/CfA/R.Kraft et al. (X-ray).

The new image shows a region less than 4.2 light-years across -- less than the distance between our sun and the nearest star. Radio-emitting features as small as 15 light-days can be seen, making this the highest-resolution view of galactic jets ever made. The study will appear in the June issue of Astronomy and Astrophysics and is available online.

Mueller and her team targeted Centaurus A (Cen A), a nearby galaxy with a supermassive black hole weighing 55 million times the sun's mass. Also known as NGC 5128, Cen A is located about 12 million light-years away in the constellation Centaurus and is one of the first celestial radio sources identified with a galaxy.

Image above: Left: The giant elliptical galaxy NGC 5128 is the radio source known as Centaurus A. Vast radio-emitting lobes (shown as orange in this optical/radio composite) extend nearly a million light-years from the galaxy. Credit: Capella Observatory (optical), with radio data from Ilana Feain, Tim Cornwell, and Ron Ekers (CSIRO/ATNF), R. Morganti (ASTRON), and N. Junkes (MPIfR). Right: The radio image from the TANAMI project provides the sharpest-ever view of a supermassive black hole's jets. This view reveals the inner 4.16 light-years of the jet and counterjet, a span less than the distance between our sun and the nearest star. The image resolves details as small as 15 light-days across. Undetected between the jets is the galaxy's 55-million-solar-mass black hole. Credit: NASA/TANAMI/Müller et al.

Seen in radio waves, Cen A is one of the biggest and brightest objects in the sky, nearly 20 times the apparent size of a full moon. This is because the visible galaxy lies nestled between a pair of giant radio-emitting lobes, each nearly a million light-years long.

These lobes are filled with matter streaming from particle jets near the galaxy's central black hole. Astronomers estimate that matter near the base of these jets races outward at about one-third the speed of light.

Image above: The elliptical galaxy NGC 5128, host of the Centaurus A radio source, as it appears in visible light. The galaxy is located about 12 million light-years away and is one of the closest that sports an active supermassive black hole. Credit: Capella Observatory.

Using an intercontinental array of nine radio telescopes, researchers for the TANAMI (Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry) project were able to effectively zoom into the galaxy's innermost realm.

"Advanced computer techniques allow us to combine data from the individual telescopes to yield images with the sharpness of a single giant telescope, one nearly as large as Earth itself," said Roopesh Ojha at NASA's Goddard Space Flight Center in Greenbelt, Md.

The enormous energy output of galaxies like Cen A comes from gas falling toward a black hole weighing millions of times the sun's mass. Through processes not fully understood, some of this infalling matter is ejected in opposing jets at a substantial fraction of the speed of light. Detailed views of the jet's structure will help astronomers determine how they form.

The jets strongly interact with surrounding gas, at times possibly changing a galaxy's rate of star formation. Jets play an important but poorly understood role in the formation and evolution of galaxies. NASA's Fermi Gamma-ray Space Telescope has detected much higher-energy radiation from Cen A's central region.

Image above: The TANAMI array consists of nine radio telescopes located on four continents. By combining data from the individual telescopes, astronomers can acquire images with the sharpness of a single telescope some 6,200 miles (10,000 km) across -- about 80 percent of Earth's diameter. Credit: Matthias Kadler (Univ. of Würzburg) and J. Wilms (Univ. of Erlangen-Nuremberg).

"This radiation is billions of times more energetic than the radio waves we detect, and exactly where it originates remains a mystery," said Matthias Kadler at the University of Wuerzburg in Germany and a collaborator of Ojha. "With TANAMI, we hope to probe the galaxy's innermost depths to find out."

Ojha is funded through a Fermi investigation on multiwavelength studies of Active Galactic Nuclei.

The astronomers credit continuing improvements in the Australian Long Baseline Array (LBA) with TANAMI's enormously increased image quality and resolution. The project augments the LBA with telescopes in South Africa, Chile and Antarctica to explore the brightest galactic jets in the southern sky.

NASA's Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy, along with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the U.S. The Australia Long Baseline Array is part of the Australia Telescope National Facility, which is funded by the Commonwealth of Australia for operation as a National Facility managed by the Commonwealth Scientific and Industrial Research Organization.

For related multimedia, visit:

For more information about TANAMI Project, visit:

Images (mentioned), Video, Text, Credits: NASA's Goddard Space Flight Center, Greenbelt, Md. / Francis Reddy.

Best regards,

Ariane 5’s third launch of 2011


20 May 2011

An Ariane 5 launcher lifted off this evening from Europe’s Spaceport in French Guiana on its mission to place two telecommunications satellites, ST-2 and GSAT-8, into their planned transfer orbits. Flight VA202 was the third Ariane 5 launch of 2011.

Liftoff of the 58th Ariane 5 mission came at 22:38 CEST (20:38 GMT; 17:38 French Guiana). The target injection orbit had a perigee altitude of 249 km, an apogee altitude at injection of 35 947 km and an inclination of 2.5º.

Ariane 5 flight VA202

The satellites were accurately injected into their transfer orbits about 27 minutes and 31 minutes after liftoff, respectively.

ST-2 will be positioned above the equator at 88°E. It will provide Internet-based fixed and mobile, voice and data transmission satellite services to businesses, in particular direct broadcast TV operators and maritime companies in Asia and the Middle East.

ST-2 satellite

GSAT-8, to be positioned over 55°E, will provide mainly direct-to-home TV broadcast and radionavigation services to the Indian subcontinent.

The payload mass for this launch was 9013 kg; the satellites totalled 8190 kg, with payload adapters and dispensers making up the additional 823 kg.

Ariane 5 flight VA202

Arianespace and Europe’s Spaceport are planning three more Ariane launches in 2011, maintaining the heavy-lift vehicle’s flight rate.

VA201 flight timeline

The Ariane 5’s cryogenic, liquid-propellant main engine was ignited first. Seven seconds later, the solid-propellant boosters also fired, and the vehicle lifted off a fraction of a second later.

The solid boosters were jettisoned 2 min 21 sec after main engine ignition, and the fairing protecting the payload during the climb through Earth’s atmosphere was discarded at 3 min 09 sec.

The launcher’s main engine was shut down at 8 min 54 sec; six seconds later, the main cryogenic stage separated from the upper stage and its payload.

Four seconds after main stage separation, the engine of the cryogenic upper stage was ignited to continue the journey. The engine was shut down at 24 min 51 sec into the flight, at which point the vehicle was travelling at 9350 m/s (33 660 km/h) at an altitude of 658.4 km. The conditions for geostationary transfer orbit injection had been achieved.

At 27 min 08 sec after main engine ignition, ST-2 separated from the upper stage, followed by GSAT-8 at 31 min 17 sec. Ariane 5’s flight operations were completed 46 min 08 sec after main engine ignition.

For more information about Arianespace, visit:

Images, Video, Text, Credits: ESA / CNES / Arianespace / Photo Optique vidéo du CSG - S. Martin.


Galileo takes its place on top of the world

ESA - GALILEO Constellation Satellites logo.

20 May 2011

Preparing for this year’s launch of the first Galileo navigation satellites, ESA today inaugurated the most northerly node in its worldwide network of Galileo ground stations. Svalbard is positioned more than 78°N, less than a thousand kilometres from the North Pole.

Located on Spitsbergen, the largest island of Norway’s Svalbard archipelago, the Svalbard Satellite Station – SvalSat for short – already serves as a ground station to numerous polar-orbiting Earth observation missions, including ESA’s Envisat and ERS-2.

Svalbard from space

SvalSat was established by the Norwegian Space Centre in 1997. However, since 2002, the station has been owned and operated by Kongsberg Satellite Services.

The formal inauguration was performed by Didier Faivre, ESA’s Director of the Galileo Programme and Navigation-related Activities; Jean-Marc Pieplu, the European Commission's Galileo Project Manager; Bo Anderson, Director-General of the Norwegian Space Centre; and Alf-Eirik Røkenes, Kongsberg’s Vice-President for Finance and Administration.


At the same time, Director Faivre and Kongsberg VP Røkenes also signed contracts for Svalbard’s operation through to the end of 2014 as well as for two further Galileo ground stations on Norwegian territory: a station to be built on Jan Mayen Island in the North Atlantic, and an existing site at Norway’s Troll base in the Antarctic.

ESA signed the contracts in its capacity as procurement agent for the Galileo programme on behalf of the European Commission.

For Galileo, SvalSat will serve as a Sensor Station to check the timing and positioning accuracy of Galileo signals, as well as an Uplink Station to transmit correction messages to the satellites as needed, sharpening the overall accuracy of Galileo navigation services.

Ground stations from pole-to-pole

Svalbard is one of the remotest Galileo ground stations. The road to Spitsbergen’s main settlement of Longyearbyen is regularly blocked by severe weather – a helicopter pad provides back-up access for the 23-strong team of engineers who operate SvalSat around the clock – and there are more polar bears than people on the island as a whole.

Galileo on the ground

There is a lot more to Galileo than just satellites in space. The worldwide ground infrastructure ESA has put in place will ensure the continued reliability of the Galileo signal’s time and positioning information.

Satellite navigation relies on the user’s receiver calculating the time and place in space that the signal was transmitted to an extremely high level of accuracy. But onboard atomic clocks can still drift, as can the orbits of the satellites themselves, perturbed by gravitational influences and the slight but significant push of sunlight.

 Galileo constellation

So ESA’s network of ground stations continuously checks each satellite’s clock for any drift, as well as performing radio-ranging on the satellites to identify any orbital perturbation. If corrections are needed, they can be embedded in the latest version of the Galileo signal that is transmitted up to the satellites to be rebroadcast.

The entire Galileo system amounts to a combined ensemble of extremely accurate clocks that can inform its users if it is running slow or fast.

Related links, Meer op Internet:

Norwegian Space Centre:

Kongsberg Satellite Services:

Galileo website (European Commission):

European GNSS Agency:

Images, Text, Credits: ESA-J. Huart / KSAT.

Best regards,

jeudi 19 mai 2011

Cassini Spacecraft And Ground Telescope See Violent Saturn Storm

NASA - Cassini Insider's Mission patch.

May 19, 2011

NASA's Cassini spacecraft and a European Southern Observatory ground-based telescope tracked the growth of a giant early-spring storm in Saturn's northern hemisphere so powerful it stretches around the entire planet. The rare storm has been wreaking havoc for months and shot plumes of gas high into the planet's atmosphere.

Image above: Thermal infrared images of Saturn from the Very Large Telescope Imager and Spectrometer for the mid-Infrared (VISIR) instrument on the European Southern Observatory's Very Large Telescope, on Cerro Paranal, Chile, appear at center and on the right. Image credit: ESO/Univ. of Oxford/T. Barry.

Cassini's radio and plasma wave science instrument first detected the large disturbance, and amateur astronomers tracked its emergence in December 2010. As it rapidly expanded, its core developed into a giant, powerful thunderstorm. The storm produced a 3,000-mile-wide (5,000-kilometer-wide) dark vortex, possibly similar to Jupiter's Great Red Spot, within the turbulent atmosphere.

The dramatic effects of the deep plumes disturbed areas high up in Saturn's usually stable stratosphere, generating regions of warm air that shone like bright "beacons" in the infrared. Details are published in this week's edition of Science Magazine.

"Nothing on Earth comes close to this powerful storm," says Leigh Fletcher, the study's lead author and a Cassini team scientist at the University of Oxford in the United Kingdom. "A storm like this is rare. This is only the sixth one to be recorded since 1876, and the last was way back in 1990."

Image above: This false-color infrared image, obtained by NASA's Cassini spacecraft, shows clouds of large ammonia ice particles dredged up by a powerful storm in Saturn's northern hemisphere. Image credit: NASA/JPL/Univ. of Arizona.

This is the first major storm on Saturn observed by an orbiting spacecraft and studied at thermal infrared wavelengths, where Saturn's heat energy reveals atmospheric temperatures, winds and composition within the disturbance.

Temperature data were provided by the Very Large Telescope (VLT) on Cerro Paranal in Chile and Cassini's composite infrared spectrometer (CIRS) operated by NASA's Goddard Space Flight Center in Greenbelt, Md.

"Our new observations show that the storm had a major effect on the atmosphere, transporting energy and material over great distances, modifying the atmospheric winds -- creating meandering jet streams and forming giant vortices -- and disrupting Saturn's slow seasonal evolution," said Glenn Orton, a paper co-author, based at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

Image above: Measurements by NASA's Cassini spacecraft reveal temperatures in a high layer of Saturn's atmosphere known as the stratosphere and show the dramatic effects of the massive storm deep below. Image credit: NASA/JPL/GSFC/Univ. Oxford.

The violence of the storm -- the strongest disturbances ever detected in Saturn's stratosphere -- took researchers by surprise. What started as an ordinary disturbance deep in Saturn's atmosphere punched through the planet's serene cloud cover to roil the high layer known as the stratosphere.

"On Earth, the lower stratosphere is where commercial airplanes generally fly to avoid storms which can cause turbulence," says Brigette Hesman, a scientist at the University of Maryland in College Park who works on the CIRS team at Goddard and is the second author on the paper. "If you were flying in an airplane on Saturn, this storm would reach so high up, it would probably be impossible to avoid it."

Other indications of the storm's strength are the changes in the composition of the atmosphere brought on by the mixing of air from different layers. CIRS found evidence of such changes by looking at the amounts of acetylene and phosphine, both considered to be tracers of atmospheric motion. A separate analysis using Cassini's visual and infrared mapping spectrometer, led by Kevin Baines of JPL, confirmed the storm is very violent, dredging up larger atmospheric particles and churning up ammonia from deep in the atmosphere in volumes several times larger than previous storms. Other Cassini scientists are studying the evolving storm, and a more extensive picture will emerge soon.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The mission is managed by JPL for NASA's Science Mission Directorate in Washington. The European Southern Observatory in Garching, Germany operates the VLT in Chile.

For information about Cassini, visit: 

Photos of the VLT:

Images (mentioned), Text, Credit: NASA / ESO.


NASA'S Galaxy Evolution Explorer Finds Dark Energy Repulsive

NASA - GALEX logo labeled.

May 19, 2011

A five-year survey of 200,000 galaxies, stretching back seven billion years in cosmic time, has led to one of the best independent confirmations that dark energy is driving our universe apart at accelerating speeds.

The survey used data from NASA's space-based Galaxy Evolution Explorer and the Anglo-Australian Telescope on Siding Spring Mountain in Australia.

The findings offer new support for the favored theory of how dark energy works – as a constant force, uniformly affecting the universe and propelling its runaway expansion. They contradict an alternate theory, where gravity, not dark energy, is the force pushing space apart. According to this alternate theory, with which the new survey results are not consistent, Albert Einstein's concept of gravity is wrong, and gravity becomes repulsive instead of attractive when acting at great distances.

Image above: In this artist's conception, dark energy is represented by the purple grid above, and gravity by the green grid below. Gravity emanates from all matter in the universe, but its effects are localized and drop off quickly over large distances. Image credit: NASA / JPL-Caltech.

"The action of dark energy is as if you threw a ball up in the air, and it kept speeding upward into the sky faster and faster," said Chris Blake of the Swinburne University of Technology in Melbourne, Australia. Blake is lead author of two papers describing the results that appeared in recent issues of the Monthly Notices of the Royal Astronomical Society. "The results tell us that dark energy is a cosmological constant, as Einstein proposed. If gravity were the culprit, then we wouldn't be seeing these constant effects of dark energy throughout time."

Dark energy is thought to dominate our universe, making up about 74 percent of it. Dark matter, a slightly less mysterious substance, accounts for 22 percent. So-called normal matter, anything with atoms, or the stuff that makes up living creatures, planets and stars, is only approximately four percent of the cosmos.

The idea of dark energy was proposed during the previous decade, based on studies of distant exploding stars called supernovae. Supernovae emit constant, measurable light, making them so-called "standard candles," which allows calculation of their distance from Earth. Observations revealed dark energy was flinging the objects out at accelerating speeds.

The new survey provides two separate methods for independently checking these results. This is the first time astronomers performed these checks across the whole cosmic timespan dominated by dark energy. Astronomers began by assembling the largest three-dimensional map of galaxies in the distant universe, spotted by the Galaxy Evolution Explorer.

"The Galaxy Evolution Explorer helped identify bright, young galaxies, which are ideal for this type of study," said Christopher Martin, principal investigator for the mission at the California Institute of Technology in Pasadena. "It provided the scaffolding for this enormous 3-D map."

Image above: This diagram illustrates two ways to measure how fast the universe is expanding -- the "standard candle" method, which involves exploded stars in galaxies, and the "standard ruler" method, which involves pairs of galaxies. Image credit: NASA / JPL-Caltech.

The team acquired detailed information about the light for each galaxy using the Anglo-Australian Telescope and studied the pattern of distance between them. Sound waves from the very early universe left imprints in the patterns of galaxies, causing pairs of galaxies to be separated by approximately 500 million light-years.

Blake and his colleagues used this "standard ruler" to determine the distance from the galaxy pairs to Earth. As with the supernovae studies, this distance data was combined with information about the speeds the pairs are moving away from us, revealing, yet again, the fabric of space is stretching apart faster and faster.

The Galaxy Evolution Explorer

The team also used the galaxy map to study how clusters of galaxies grow over time like cities, eventually containing many thousands of galaxies. The clusters attract new galaxies through gravity, but dark energy tugs the clusters apart. It slows down the process, allowing scientists to measure dark energy's repulsive force.

"Observations by astronomers over the last 15 years have produced one of the most startling discoveries in physical science; the expansion of the universe, triggered by the big bang, is speeding up," said Jon Morse, astrophysics division director at NASA Headquarters in Washington. "Using entirely independent methods, data from the Galaxy Evolution Explorer have helped increase our confidence in the existence of dark energy."

For more information about NASA's Galaxy Evolution Explorer, visit:

Images (mentioned), Text, Credits: NASA / JPL-Caltech.


JAXA conducts first phase of D-SEND project

JAXA logo labeled.

May 19, 2011 (JST)

The Japan Aerospace Exploration Agency (JAXA) successfully conducted the first phase of the "Drop test for Simplified Evaluation of Non-symmetrically Distributed sonic boom*1" (D-SEND) twice on May 7 and 16, 2011 (Sweden Standard Time) at the Esrange Space Center in Sweden in cooperation with the Swedish
Space Corporation (SSC). JAXA has, for the first time in the world, confirmed the validity of low sonic boom axisymmetric*2 design by a balloon drop test.

Establishing low sonic boom design technology is one of the highest priority issues for realizing silent supersonic transport. As part of silent supersonic research, JAXA is carrying out the two phased D-SEND project to validate its low sonic boom design concept and to contribute to the deliberation of
international standards for sonic booms based on the acquired data.

In the first phase called D-SEND#1, two different axisymmetric bodies were dropped from a balloon, and the sonic booms, measured both in the air and on the ground, were compared with each other. Through this test, JAXA has successfully demonstrated its low sonic boom axisymmetric design concept technology which reduced the sonic boom by half.

The data obtained from the test is valuable as a reference for the validation of the sonic boom propagation analysis method and is expected to contribute to low-sonic boom studies in the future. JAXA has also established for the first time a new method of demonstrating the low sonic boom design concept in the
form of a balloon drop test.

JAXA expresses our sincere gratitude to the Swedish Space Corporation and all parties that provided assistance in this demonstration test.

*1 sonic boom
   A sonic boom is a kind of impulsive sound of shockwaves, similar to thunder,
   generated by supersonic flight

*2 axisymmetric
   Typical axisymmetric shapes include cone, cylinder, etc.

For more details, please refer to the following website:

1. Test details

Two test bodies, namely the N-wave model and the low-boom model are dropped consecutively from an altitude of 20-30km. The sonic boom generated by the free-fall is measured by using a low-boom measurement system and a boom measurement system.

Sequence of D-SEND#1

Place:     Swedish Space Corporation (SSC), at Esrange Test Site (Kiruna, Sweden)
Role Sharing:        Measurement of sonic booms in the air and on the ground (JAXA)
Management of measurement balloon and dropping of test models (SSC)

2. Test conditions

Correlation of velocity and altitude after the release

Preparation of balloon and test models(1st test) /
Balloon ascending into the sky (1st test)

3. Measurement Results

Pressure metamorphose time records measured by microphones in the air altitude of 500m (Pressure signature) are described below.

The characteristic N-type wave was clearly measured by N Wave Model (NWM) in the tests. Meanwhile, the low-boom model validated that its sonic boom could be reduced by comparing NWM.

4. Schedule of future tests

We will further analyze the obtained data and then report the results at a meeting of the SuperSonic Task Group (SSTG) of the International Civil Aviation Organization (ICAO) *3 in November.


ICAO is one of the specialized agencies of the United Nations Economic and Social Council, and codifies the treaty, international standard, recommendation and guideline related to international air services to ensure economical and substantial operation of the international air transportation business based on the principle of equal opportunity.

Mission website:

Research on Super/Hyper Sonic Airplane:

Images, Graphics, Text, Credit: Japan Aerospace Exploration Agency (JAXA).

Best regards,

mercredi 18 mai 2011

Free-Floating Planets May Be More Common Than Stars

NASA patch.

May 18, 2011

Astronomers, including a NASA-funded team member, have discovered a new class of Jupiter-sized planets floating alone in the dark of space, away from the light of a star. The team believes these lone worlds probably were ejected from developing planetary systems.

Image above: This artist's conception illustrates a Jupiter-like planet alone in the dark of space, floating freely without a parent star. Astronomers recently uncovered evidence for 10 such lone worlds, thought to have been "booted," or ejected, from developing solar systems.

The discovery is based on a joint Japan-New Zealand survey that scanned the center of the Milky Way galaxy during 2006 and 2007, revealing evidence for up to 10 free-floating planets roughly the mass of Jupiter. The isolated orbs, also known as orphan planets, are difficult to spot, and had gone undetected until now. The planets are located at an average approximate distance of 10,000 to 20,000 light years from Earth.

"Although free-floating planets have been predicted, they finally have been detected, holding major implications for planetary formation and evolution models," said Mario Perez, exoplanet program scientist at NASA Headquarters in Washington.

The discovery indicates there are many more free-floating Jupiter-mass planets that can't be seen. The team estimates there are about twice as many of them as stars. In addition, these worlds are thought to be at least as common as planets that orbit stars. This adds up to hundreds of billions of lone planets in our Milky Way galaxy alone.

"Our survey is like a population census," said David Bennett, a NASA and National Science Foundation-funded co-author of the study from the University of Notre Dame in South Bend, Ind. "We sampled a portion of the galaxy, and based on these data, can estimate overall numbers in the galaxy."

The study, led by Takahiro Sumi from Osaka University in Japan, appears in the May 19 issue of the journal Nature.

The survey is not sensitive to planets smaller than Jupiter and Saturn, but theories suggest lower-mass planets like Earth should be ejected from their stars more often. As a result, they are thought to be more common than free-floating Jupiters.

Previous observations spotted a handful of free-floating planet-like objects within star-forming clusters, with masses three times that of Jupiter. But scientists suspect the gaseous bodies form more like stars than planets. These small, dim orbs, called brown dwarfs, grow from collapsing balls of gas and dust, but lack the mass to ignite their nuclear fuel and shine with starlight. It is thought the smallest brown dwarfs are approximately the size of large planets.

On the other hand, it is likely that some planets are ejected from their early, turbulent solar systems, due to close gravitational encounters with other planets or stars. Without a star to circle, these planets would move through the galaxy as our sun and others stars do, in stable orbits around the galaxy's center. The discovery of 10 free-floating Jupiters supports the ejection scenario, though it's possible both mechanisms are at play.

"If free-floating planets formed like stars, then we would have expected to see only one or two of them in our survey instead of 10," Bennett said. "Our results suggest that planetary systems often become unstable, with planets being kicked out from their places of birth."

The observations cannot rule out the possibility that some of these planets may have very distant orbits around stars, but other research indicates Jupiter-mass planets in such distant orbits are rare.

Lone Planet Under a Cosmic Magnifying Glass

Video above: This artist's animation illustrates the technique used for finding free-floating, Jupiter-mass planets in space. Astronomers found evidence for 10 of these worlds, thought to have been ejected early on from their developing solar systems.

The survey, the Microlensing Observations in Astrophysics (MOA), is named in part after a giant wingless, extinct bird family from New Zealand called the moa. A 5.9-foot (1.8-meter) telescope at Mount John University Observatory in New Zealand is used to regularly scan the copious stars at the center of our galaxy for gravitational microlensing events. These occur when something, such as a star or planet, passes in front of another more distant star. The passing body's gravity warps the light of the background star, causing it to magnify and brighten. Heftier passing bodies, like massive stars, will warp the light of the background star to a greater extent, resulting in brightening events that can last weeks. Small planet-size bodies will cause less of a distortion, and brighten a star for only a few days or less.

A second microlensing survey group, the Optical Gravitational Lensing Experiment (OGLE), contributed to this discovery using a 4.2-foot (1.3 meter) telescope in Chile. The OGLE group also observed many of the same events, and their observations independently confirmed the analysis of the MOA group.

For more information about NASA's exoplanet research, visit: 

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


Endeavour docks with Space Station


NASA - STS-134 Mission patch / AMS-02 Mission patch.

18 May 2011

Space Shuttle Endeavour arrived at the International Space Station today at 12:14 CEST (10:14 GMT) after chasing it in space after a textbook launch on Monday. The crews have now started their combined operations.

STS-134 Endeavour's last docking at the ISS

 The hatches between the Space Shuttle and Space Station were opened after leak tests at 13:38 and ESA astronaut Roberto Vittori and his five crewmates floated in the Space Station at 14:36 today. They were welcomed by Expedition 27 astronauts, including ESA’s another Italian astronaut, Paolo Nespoli. The two Italians were the first astronauts to meet after the hatches were opened.

Endeavour and Columbus seen after docking

The main payload of the Shuttle is a AMS-02, one of the most exciting scientific instruments ever built - an experiment that could change our understanding of the Universe. After being installed tomorrow, it will be the largest science experiment on the Station.

The installation will be done by careful choreography of the Space Shuttle robot arm and ISS robot arm: the huge instrument will be picked up by the Shuttle’s arm from the cargo bay of Endeavour and handed over to ISS arm, which will crane the AMS-02 to the far-away attaching point on the upper side of the ISS central truss.

Paolo Nespoli giving a safety briefing to visitors

Roberto Vittori will play an important role in these robotic manoeuvres.

During the 16-day STS-134 mission the astronauts from Endeavour will do four spacewalks and also install spare parts and micrometeoroid shields to the Space Station. After these works and in total 36 Shuttle visits, the orbital outpost is ready for a multitude of uses, ranging from performing fundamental science experiments to preparing for the exploration of deep space.

Paolo coming home

After almost six days of combined operations, the six-men-crew of Endeavour and three ISS astronauts – Andrei Borisenko, Aleksandr Samokutyayev and Ron Garan – will say goodbye to Dmitri Kondratyev, Catherine Coleman and Paolo Nespoli, who have been aboard the ISS since last December.

Astronauts posing in the Harmony node

The leaving trio will take a Soyuz TMA-20 on Tuesday night, depart from the nadir docking port of the Rassvet docking module at 00:06 CEST on 23 May (22:06 GMT on 22 May).

The landing is supposed to happen about three hours later, at 3:26 CEST (01:26 GMT), to the steppes of Kazakhstan when Sun has just risen over the local horizon.

Science on DAMA mission

Roberto’s mission has been named as DAMA after the mystical form of matter – ‘dark matter’ – that fills the universe with even more strange dark energy, according to theories. AMS-02 will detect this ‘dark matter’ and antimatter by observing the cosmic rays, helping us hopefully to better understand the origin and structure of the Universe.


In addition, Roberto will act as a test subject for two ESA life science experiments and perform six studies sponsored by the Italian space agency, ASI, in technology, medicine, biology and material science.

STS-134 Endeavour preparing for final dock with ISS
Endeavour is scheduled to depart the Station in early morning hours of Monday 30 May (CEST) and land at the Kennedy Space Center on 1 June.

Related links:

DAMA Mission:

Last Shuttle with ESA astronaut lifts off to Space Station to hunt ‘dark matter’:

STS-134 mission (NASA):

Images, Videos, Text, Credits: ESA / NASA / AMS-02 Collaboration / Youtube.


lundi 16 mai 2011

NASA's Shuttle Endeavour Heads To Space Station On Its Final Mission


NASA - STS-134 Mission patch / AMS-02 Mission patch.

May 16, 2011

Space shuttle Commander Mark Kelly and his five crewmates are on their way to the International Space Station after launching from NASA's Kennedy Space Center at 8:56 a.m. EDT Monday. The STS-134 mission is the penultimate orbiter flight and the final one for shuttle Endeavour.

Endeavour launch

"This mission represents the power of teamwork, commitment and exploration," Commander Mark Kelly said shortly before liftoff. "It is in the DNA of our great country to reach for the stars and explore. We must not stop. To all the millions watching today including our spouses, children, family and friends, we thank you for your support."

AMS-02 mounted on the upper Payload Attach Point on the main truss of the ISS (left)

The crew will deliver the Alpha Magnetic Spectrometer-2 (AMS) and critical supplies to the space station, including two communications antennas, a high-pressure gas tank and additional parts for the Dextre robot. AMS is a particle physics detector designed to search for various types of unusual cosmic matter. The crew also will transfer Endeavour's orbiter boom sensor system to the station, where it could assist spacewalkers as an extension for the station's robotic arm.

Space Shuttle Endeavor Final Launch - Mon, 16th May 2011

"Today's final launch of Endeavour is a testament to American ingenuity and leadership in human spaceflight," NASA Administrator Charles Bolden said. "As we look toward a bright future with the International Space Station as our anchor and new destinations in deep space on the horizon, we salute the astronauts and ground crews who have ensured the orbiter's successful missions. The presence of Congresswoman Gabrielle Giffords at the launch inspired us all, just as America's space program has done for the past 50 years."

Kelly's crewmates are Pilot Greg H. Johnson and Mission Specialists Mike Fincke, Drew Feustel, Greg Chamitoff and Roberto Vittori of the European Space Agency. This is the first shuttle flight for Fincke and Vittori. Vittori will be the last international astronaut to fly aboard a shuttle.

Endeavour's Final Voyage

Endeavour is scheduled to dock to the station at 6:15 a.m. on Wednesday. The 16-day mission includes four spacewalks. After undocking to return to Earth, Kelly and Johnson will ease the shuttle back toward the station to test new sensor technologies that could facilitate the docking of future space vehicles to the station.

The shuttle's first landing opportunity at Kennedy is scheduled for 2:32 a.m. on June 1. STS-134 is the 134th shuttle flight, the 25th flight for Endeavour and the 36th shuttle mission dedicated to station assembly and maintenance.

NASA's web coverage of STS-134 includes mission information, a press kit, interactive features, news conference images, graphics and videos. Mission coverage, including the latest NASA Television schedule, is available on the main space shuttle website at:

NASA is providing continuous television and Internet coverage of the mission. NASA TV features live mission events, daily status news conferences and 24-hour commentary. For NASA TV streaming video, downlink and schedule information, visit:

Daily news conferences with STS-134 mission managers will take place at NASA's Johnson Space Center in Houston. Live updates to the NASA News Twitter feed will be added throughout the mission and landing. To access the feed, go to the homepage or visit:

Kelly, Johnson, Fincke and Chamitoff are providing updates to their Twitter accounts during the mission. They can be followed at:

For more information about the space station, visit:

Images, Video, Text, Credits: NASA / ESA.

Best regards,

Comets WISE -- A Family Portrait

NASA - WISE Mission patch.

May 14, 2011

During its one-year mission, NASA's Wide-field Infrared Survey Explorer, or WISE, mapped the entire sky in infrared light. Among the multitudes of astronomical bodies that have been discovered by the NEOWISE portion of the WISE mission are 20 comets. This collage shows those 20 new comets together in a kind of family portrait.

The fuzzy background in each picture is due to random fluctuations in infrared light, primarily from dust in our own solar system. Stars cannot be seen because they were subtracted during the process of combining multiple WISE pictures to make this view centered on the moving comets.

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


Galaxy NGC 4214: A star formation laboratory

ESA - Hubble Space Telescope logo.

12 May 2011

Image above: Hubble’s newest camera has taken an image of galaxy NGC 4214. This galaxy glows brightly with young stars and gas clouds, and is an ideal laboratory to research star formation and evolution.

Size isn’t everything... in astronomy, at least. Dwarf galaxy NGC 4214 may be small, but what it lacks in size it makes up for in content. It is packed with everything an astronomer could ask for, from hot, young star-forming regions to old clusters with red supergiants.

The intricate patterns of glowing ionised hydrogen gas, cavities blown clear of gas by stellar wind, and bright stellar clusters of NGC 4214 can be seen in this optical and near-infrared image, taken using the Wide Field Camera 3 (WFC3) instrument on the NASA/ESA Hubble Space Telescope.

Image above: A huge heart-shaped cavity — possibly the galaxy’s most eye-catching feature — can be seen at the centre of the image. Inside this hole lies a large cluster of massive, young stars ranging in temperature from 10 000 to 50 000 degrees Celsius. Their strong stellar winds are responsible for the creation of this hollow area. The resulting lack of gas prevents any further star formation from occurring in this region.

Located around 10 million light-years away in the constellation of Canes Venatici (The Hunting Dogs), the galaxy’s relative close proximity to us, combined with the wide variety of evolutionary stages among the stars, makes it an ideal laboratory to research what triggers star formation and evolution. By chance, there is relatively little interstellar dust between us and NGC 4214, making our measurements of it more accurate.

Hubble - Zooming in on NGC 4214
NGC 4214 contains a large amount of gas, some of which can be seen glowing red in the image, providing abundant material for star formation. The area with the most hydrogen gas, and consequently, the youngest clusters of stars (around two million years old), lies in the upper part of this Hubble image. Like most of the features in the image, this area is visible due to ionisation of the surrounding gas by the ultraviolet light of a young cluster of stars within.

Hubble - Pan over NGC 4214

Observations of this dwarf galaxy have also revealed clusters of much older red supergiant stars that we see at a late stage in their evolution. Additional older stars can be seen dotted all across the galaxy. While these are dominant in infrared emission they can only be seen shining faintly in this visible-light image. The variety of stars at different stages in their evolution, indicate that the recent and ongoing starburst periods are by no means the first, and the galaxy’s numerous ionised hydrogen regions suggest they will not be the last.


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

Image credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration

Acknowledgment: R. O’Connell (University of Virginia) and the WFC3 Scientific Oversight Committee


    * Images of Hubble:

    * NASA release:

Images, Text, Credit: NASA, ESA and the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration. Acknowledgment: R. O’Connell (University of Virginia) and the WFC3 Scientific Oversight Committee / NASA, ESA, Digitized Sky Survey 2 / Videos: Image credit: Credit: NASA, ESA, Digitized Sky Survey 2, Faulkes Telescope Project (part of LCOGT) and the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration. Acknowledgment: R. O’Connell (University of Virginia) and the WFC3 Scientific Oversight Committee.