samedi 20 décembre 2014
The ISS crew receives a new tool by email
ISS - International Space Station patch.
With a 3D printer, the astronauts on the International Space Station could make some kind of wrench the design was sent to them from Earth.
Image Above: Astronaut Butch Wilmore, commander of the ISS, proudly brandishes his new tool. Image Credit: NASA.
This is the first time that the crew was able to cobble together a tool that was missing with a 3D printer made especially for weightlessness. The spanner was designed by Made in Space, the California-based company that created the printer. The latter had already been used in the space station but only on drawings and uploaded tested first on Earth.
This time, the spanner has been designed and tested on Earth and his drawing emailed to the printer, who made subject to some 4 hours, the company said in a statement. "The spanner was designed with removable parts without need of other materials," said a statement from the company.
Image Above: Made In Space's 3D printer, specially designed for use in microgravity on the International Space Station (ISS). Image Credit: NASA.
A prototype has been printed in a California lab and sent to NASA for her to inspect before the drawing goes to the ISS. The entire process, from design to execution, took less than a week.
The spanner like any other printed objects in the station, will be brought to Earth to be compared with printed objects normally.
For more information about the International Space Station (ISS), visit: http://www.nasa.gov/mission_pages/station/main/index.html
Images (mentioned), Text, Credits: NASA/Orbiter.ch Aerospace.
Best regards, Orbiter.ch
Publié par Orbiter.ch à 18:20
CERN - LHC filling with liquid helium at 4 kelvin
CERN - European Organization for Nuclear Research logo.
December 20, 2014
CERN gears up to cool LHC down
Last week the cryogenics team at CERN finished filling the arc sections of the Large Hadron Collider (LHC) with liquid helium. The helium, which is injected into magnets that steer particle beams around the 27-kilometre accelerator, cools the machine to below 4 degrees kelvin (-269.15°C).
The process of filling the LHC is an important milestone on the road to restarting the accelerator at higher energy, though it will still take many weeks to cool the entire accelerator to its nominal operating temperature of 1.9 K (-271.3°C).
The electromagnets that steer particle beams around the LHC must be kept cold enough to operate in a superconducting state – the temperature at which electricity can pass through a material without losing energy to resistance. The niobium-titanium wires that form the coils of the LHC’s superconducting magnets are therefore maintained at 1.9 K by a closed liquid-helium circuit. This is colder than the average temperature – 2.7 K – in outer space.
Large Hadron Collider (LHC)
Some 1292 dipole magnets will produce a magnetic field of 8.33 tesla to keep particle beams on course around the LHC's 27-kilometre ring. A current of 11,850 amps in the magnet coils is needed to reach magnetic fields of this amplitude. The use of superconducting materials has proved to be the best – and most cost-effective – way to avoid overheating the coils.
CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.
The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.
Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 20 Member States.
Large Hadron Collider (LHC): http://home.web.cern.ch/topics/large-hadron-collider
Find out more:
Cryogenics at the LHC: http://home.web.cern.ch/about/engineering/cryogenics-low-temperatures-high-performance
About the higher energy restart: http://home.web.cern.ch/about/engineering/restarting-lhc-why-13-tev
Image, Text, Credits: CERN/Cian O'Luanaigh/Video: Noemi Caraban Gonzalez.
Publié par Orbiter.ch à 17:45
Signs of Europa Plumes Remain Elusive in Search of Cassini Data
NASA - Cassini International logo.
December 20, 2014
Image above: Jupiter's icy moon Europa displays many signs of activity, including its fractured crust and a dearth of impact craters. Scientists continue to hunt for confirmation of plume activity. Image Credit: NASA/JPL-Caltech/SETI Institute.
-- Data from Cassini's 2001 Jupiter flyby show Europa contributes less material to its surrounding environment than previously thought.
-- Unlike Saturn's known-active moon Enceladus, Europa is surrounded by very tenuous hot, excited gas.
A fresh look at data collected by NASA's Cassini spacecraft during its 2001 flyby of Jupiter shows that Europa’s tenuous atmosphere is even thinner than previously thought and also suggests that the thin, hot gas around the moon does not show evidence of plume activity occurring at the time of the flyby. The new research provides a snapshot of Europa's state of activity at that time, and suggests that if there is plume activity, it is likely intermittent.
The Europa results are being presented today at the American Geophysical Union fall meeting in San Francisco and published in the Astrophysical Journal. Europa is considered one of the most exciting destinations in the solar system for future exploration because it shows strong indications of having an ocean beneath its icy crust.
Members of Cassini's ultraviolet imaging spectrograph (UVIS) team analyzed data collected by their instrument during the brief time it observed Europa in 2001, as Cassini sped through the Jupiter system en route to Saturn. The observations show that most of the hot, excited gas, or plasma, around Europa originates not from the moon itself, but from volcanoes on the nearby moon Io. In fact, from their data, the researchers calculated that Europa contributes 40 times less oxygen than previously thought to its surrounding environment.
"Our work shows that researchers have been overestimating the density of Europa's atmosphere by quite a bit," said Don Shemansky, a Cassini UVIS team member with Space Environment Technologies in Pasadena, California, who led the study. The team found that the moon's tenuous atmosphere, which was already thought to be millions of times thinner than Earth’s atmosphere, is actually about 100 times less dense than those previous estimates.
A downward revision in the amount of oxygen Europa pumps into the environment around Jupiter would make it less likely that the moon is regularly venting plumes of water vapor high into orbit, especially at the time the data was acquired.
Scientists would expect that ongoing plume activity at Europa, as Cassini has observed at Saturn's moon Enceladus, would inject large amounts of water vapor into the area around Europa's orbit if the plumes were large enough, but that is not what UVIS observed.
"We found no evidence for water near Europa, even though we have readily detected it as it erupts in the plumes of Enceladus," said Larry Esposito, UVIS team lead at the University of Colorado at Boulder.
"It is certainly still possible that plume activity occurs, but that it is infrequent or the plumes are smaller than we see at Enceladus," said Amanda Hendrix, a Cassini UVIS team member with the Planetary Science Institute in Pasadena, who co-authored the new study. "If eruptive activity was occurring at the time of Cassini's flyby, it was at a level too low to be detectable by UVIS."
Cassini spacecraft. Image Credits: NASA/JPL
Indications of possible plume activity were reported in 2013 by researchers using NASA's Hubble Space Telescope, launching a wave of interest in searching for additional signs, including this effort by the UVIS team. Cassini's 2001 Jupiter flyby provided UVIS the opportunity to directly measure the environment near Europa, which is not possible with Hubble.
For more than a decade, Cassini's UVIS has observed the cold, dense doughnut of gas that encloses the orbit of Enceladus. There, the massive amount of gas being breathed into orbit around Saturn by the Enceladus plumes acts like a brake on electrons being dragged through it by Saturn's magnetic field, which rotates with the planet. This braking helps to keep down the temperature of the plasma. Apparently there is no such brake at Europa.
Since UVIS saw a hot plasma, rather than a cold one, around Europa's orbit, it suggests Europa is not outputting large amounts of gas -- including water.
Snapshots provided by missions that visited Jupiter prior to Cassini provided strong indications that Io is the major contributor of material to the environment around Jupiter, and indicated a hot, low density plasma surrounding Europa. The new results confirm that. "Io is the real monster here," Shemansky said.
“Europa is a complex, amazing world, and understanding it is challenging given the limited observations we have,” said Curt Niebur, Outer Planets program scientist at NASA Headquarters in Washington. “Studies like this make the most of the data we have and help guide the kinds of of science investigations NASA should pursue in the future.”
Scientists are currently using the Hubble Space Telescope to conduct an extensive six-month long survey looking for plume activity, and NASA is also studying various possible Europa missions for future exploration.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. JPL designed, developed and assembled the Cassini orbiter. The UVIS team is based at the University of Colorado, Boulder, where the instrument was designed and built.
More information about Cassini: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov and http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens
More information about Europa: http://solarsystem.nasa.gov/europa
Images (mentioned), Text, Credits: NASA/JPL/Preston Dyches.
Publié par Orbiter.ch à 13:31
XMM-Newton spots monster black hole hidden in tiny galaxy
ESA - XMM-Newton Mission patch.
20 December 2014
First impressions can be deceptive – astronomers have used ESA's X-ray satellite XMM-Newton to find a massive black hole hungrily feeding within a tiny dwarf galaxy, despite there being no hint of this black hole from optical observations.
The galaxy, an irregular dwarf named J1329+3234, is one of the smallest galaxies yet to contain evidence of a massive black hole. Located over 200 million light-years away, the galaxy is similar in size to the Small Magellanic Cloud, one of our nearest neighbouring galaxies, and contains a few hundred million stars.
Image above: X-ray emission from dwarf galaxy J1329+3234. Credit: ESA/XMM-Newton/N. Secrest, et al. (2015).
In 2013, an international team of astronomers was intrigued to discover infrared signatures of an accreting black hole within J1329+3234 when they studied it with the Wide-Field Infrared Survey Explorer (WISE).
The same team has now investigated the galaxy further, using ESA's XMM-Newton to hunt for this black hole in X-rays – and found something very surprising.
"The X-ray emission from J1329+3234 is over 100 times stronger than expected for this galaxy," says Nathan Secrest of George Mason University in Virginia, USA, lead author of the new study published in The Astrophysical Journal. "We would typically expect to find low-level X-ray emission from stellar-mass black holes within the galaxy, but what we found instead was emission consistent with a very massive black hole."
The combined X-ray and infrared properties of this galaxy can only be explained by the presence of a massive black hole residing in J1329+3234, similar to the supermassive black holes found at the centres of much more massive galaxies.
While the exact mass of the black hole is not known, it must be at least 3000 times as massive as the Sun, although it is likely to be much more massive than that. If the black hole in J1329+3234 is similar to known low-mass supermassive black holes, then it has a mass of around 150 000 times that of the Sun.
A feeding black hole at the centre of a galaxy is known as an active galactic nucleus, or AGN. In the region surrounding the black hole, material from the galaxy emits intensely bright radiation as it swirls inwards towards the centre of the galaxy and is devoured by the black hole. AGNs powered by massive black holes are commonplace in large galaxies, but they appear to be rarer in galaxies without a central "bulge" of stars – dwarf galaxies being a key example.
"This is a really important discovery," says co-author Shobita Satyapal, also from George Mason University. "It's interesting enough that such a tiny galaxy has such a large black hole, but this also raises questions about how these black holes form in the first place."
Image above: Artist's impression of accreting black hole in a dwarf galaxy. Credit: ESA/ATG medialab.
Astronomers believe that the "seeds" of massive black holes formed very early on in the Universe, along with the first generation of stars. These seed black holes then grew into massive black holes via a string of galaxy mergers. As the galaxies merged, so did their central black holes.
The turbulent merging process would feed the accreting black holes with copious amounts of material while simultaneously building up large, bulge-dominated galaxies. However, with each successive merger information about the properties of the original black hole is lost, meaning that astronomers cannot determine the mass of the original seeds by looking at massive bulge-dominated galaxies – instead they probe their dwarf and bulgeless relatives, such as J1329+3234, for clues.
Finding a massive black hole within such a tiny bulgeless galaxy provides support for the theory that black holes may have grown very efficiently within the gaseous haloes of forming galaxies, originating in massive, collapsing clouds of primordial gas.
Along with J1329+3234, Secrest and his colleagues found several hundred other bulgeless galaxies from the WISE survey that also show intriguing infrared properties – many of which, like J1329+3234, display no evidence for AGNs in optical light.
"The idea that we could find an accreting black hole even in a galaxy with no optical evidence for one is exciting," notes Secrest. "Massive black holes and AGNs may be much more common within low mass and bulgeless galaxies than we currently think."
ESA's X-ray satellite XMM-Newton. Image Credit: ESA
In recent years, growing numbers of massive black holes have been identified within dwarf and bulgeless galaxies. However, it is much harder to find them than it is to find their supermassive counterparts – they are less likely to show up in optical studies since they are often obscured by dust and are usually much dimmer, making them difficult to detect above surrounding light.
This emphasises the importance of multi-wavelength sky surveys, says ESA's XMM-Newton project scientist Norbert Schartel. "Using a mix of optical, infrared, and X-ray observations was vital here," he adds. "The sensitivity of XMM-Newton made it possible not only to discover this black hole but to also fully characterise its spectrum, meaning we can say with much more certainty that it's a black-hole-fuelled AGN."
"An optically obscured AGN in a low mass, irregular dwarf galaxy: A multi-wavelength analysis of J1329+3234" by N. Secrest et al. is published in The Astrophysical Journal: http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=55160
The European Space Agency's X-ray Multi-Mirror Mission, XMM-Newton, was launched in December 1999. The largest scientific satellite to have been built in Europe, it is also one of the most sensitive X-ray observatories ever flown. More than 170 wafer-thin, cylindrical mirrors direct incoming radiation into three high-throughput X-ray telescopes. XMM-Newton's orbit takes it almost a third of the way to the Moon, allowing for long, uninterrupted views of celestial objects.
For more information about XMM-Newton mission, visit: http://www.esa.int/Our_Activities/Space_Science/XMM-Newton_overview
Images (mentioned), Text, Credit: ESA.
Best regards, Orbiter.ch
Publié par Orbiter.ch à 08:21
Video Gives Astronaut’s-Eye View Inside NASA’s Orion Spacecraft
NASA - ORION EFT-1 Mission logo.
December 20, 2014
Astronaut’s-Eye View of NASA’s Orion Spacecraft Re-entry
Video above: New video recorded during NASA’s Orion return through Earth’s atmosphere provides viewers a taste of what the vehicle endured as it returned through Earth’s atmosphere during its Dec. 5 flight test. Image Credit: NASA.
New video recorded during the return of NASA’s Orion through Earth’s atmosphere this month provides a taste of the intense conditions the spacecraft and the astronauts it carries will endure when they return from deep space destinations on the journey to Mars.
Among the first data to be removed from Orion following its uncrewed Dec. 5 flight test was video recorded through windows in Orion’s crew module. Although much of the video was transmitted down to Earth and shown in real time on NASA Television, it was not available in its entirety. Also, the blackout caused by the superheated plasma surrounding the vehicle as it endured the peak temperatures of its descent prevented downlink of any information at that key point. However, the cameras were able to record the view and now the public can have an up-close look at the extreme environment a spacecraft experiences as it travels back through Earth's environment from beyond low-Earth orbit.
The video begins 10 minutes before Orion's 11:29 a.m. EST splashdown in the Pacific Ocean, just as the spacecraft was beginning to experience Earth's atmosphere. Peak heating from the friction caused by the atmosphere rubbing against Orion's heat shield comes less than two minutes later, and the footage shows the plasma created by the interaction change from white to yellow to lavender to magenta as the temperature increases.
As Orion emerges safely on the other side of its trial by fire, the camera continues to record the deployment of the series of parachutes that slowed it to a safe 20 mph for landing and the final splash as Orion touched down on Earth.
Image above: NASA's Orion spacecraft is viewed by members of the media at the Launch Abort System Facility at NASA's Kennedy Space Center in Florida. Orion made the 8-day, 2,700 mile overland trip back to Kennedy from Naval Base San Diego in California. Analysis of date obtained during its two-orbit, four-and-a-half hour mission Dec. 5 will provide engineers detailed information on how the spacecraft fared. The Ground Systems Development and Operations Program led the recovery, offload and transportation efforts. Image Credit: NASA/Dimitri Gerondidakis.
Orion was then retrieved by a combined NASA, U.S. Navy and Lockheed Martin team and carried back to shore aboard the Navy's USS Anchorage. After returning to shore, it was loaded on to a truck and driven back to NASA's Kennedy Space Center in Florida, where it arrived on Thursday.
Orion traveled 3,600 miles above Earth on its 4.5-hour flight test – farther than any spacecraft built for humans has been in more than 40 years. In coming back from that distance, it also traveled faster and experienced hotter temperatures – 20,000 mph and near 4,000 degrees Fahrenheit, to be exact. Orion will travel faster and experience even higher temperatures on future missions, when it returns from greater distances, but this altitude allowed engineers to perform a good checkout of Orion's critical systems – in particular its heat shield.
Orion's flight test was a critical step on NASA's journey to Mars. Work already has begun on the next Orion capsule, which will launch for the first time on top of NASA's new Space Launch System rocket and travel to a distant retrograde orbit around the moon.
To view the video of Orion’s re-entry, visit: https://www.youtube.com/watch?v=MtWzuZ6WZ8E
For information about Orion, visit: http://www.nasa.gov/orion
Image (mentioned) , Video (mentioned), Text, Credits: NASA/Rachel Kraft/Johnson Space Center/Brandi Dean.
Publié par Orbiter.ch à 07:58
vendredi 19 décembre 2014
Launch of RS-18 rocket carrying a Kondor-E radar satellite into orbit
December 19, 2014
RS-18 rocket was launched out of a rocket silo at Site 175/59 at the Baikonur
A Russian RS-18 rocket was launched out of a rocket silo at Site 175/59 at the Baikonur Cosmodrome at 4:43 UTC (7 hours 43 minutes Moscow time) on Friday, embarking on its third overall mission since being inaugurated in 2003, carrying a Kondor-E radar satellite into orbit for operation by South African Defence & Intelligence Agencies. The launch came after a one-day delay as technical problems kept Kondor-E on the ground on Thursday, set to deliver high resolution radar imagery for a variety of applications.
Confirmation of a successful orbital insertion was provided by the Russian Space Agency several hours after liftoff and orbital tracking has shown Kondor-E in the expected orbit.
RS-18 rocket carrying a Kondor-E radar satellite, trail in the sky
20 years in the making, the Kondor program saw its first launch in 2013 when the first satellite was orbited for operation by the Russian military. Manufactured by NPO Mash, the Kondor satellites can carry optical imaging instruments or radar payloads for use by Russian operators or by foreign agencies under the Kondor-E designation.
Kondor-E 1 radar satellite
South Africa procured the first Kondor-E satellite in 2006 under a top secret program codenamed Flute. Delays in the launch of the first Kondor satellite also pushed the launch of the first export version and even after the first Kondor spread its wings, the launch of the second satellite encountered several launch delays from late 2013 into 2014 end eventually to December. Despite criticism claiming that there was no need for the operation of a radar satellite by South Africa, the government pressed on with the project that reportedly consumed $120 million of funding in the past eight years.
The road to launch was relatively bumpy as conflicts on operational requirements emerged from the South African side, not agreeing to NPO Mash being the operator of the satellite with South Africa’s role reduced to issuing imaging requests and receiving imagery at the discretion of NPO Mash.
ROSCOSMOS Press Release: http://www.federalspace.ru/21206/
Images, Text, Credits: Press Service of the Russian Federal Space Agency/NPO Mash/Orbiter.ch Aerospace.
Publié par Orbiter.ch à 17:37
India launches largest rocket into space and unmanned capsule
ISRO - Indian Space Research Organization logo.
December 19, 2014
GSLV Mk-III X / CARE Mission
Yesterday 18 December, India has successfully launched its largest rocket and an unmanned capsule which could send astronauts into space. The rocket called the Geosynchronous Satellite Launch Vehicle (GSLV) Mark 3 successfully launched December 18th 2014 at 04:00 UTC.
The 630-tonne Geosynchronous Satellite Launch Vehicle (MK III) blasted off from Sriharikota in the southern state of Andhra Pradesh on Thursday morning.
Launch of New Indian GSLV MkIII with Test Capsule
The new rocket will be able to carry heavier satellites into space. India has successfully launched lighter satellites in recent years, but has faced problems sending up heavier payloads.
The new rocket is capable of carrying communication satellites weighing 4,000kg, reports say, meaning India will not have to rely on foreign launchers to do so.
Image above: The CARE crew module prototype will be attached to the third stage of the GSLV Mark III rocket in "upside down" position. Image credit: ISRO.
Prime Minister Narendra Modi tweeted after the launch: "Successful launch of GSLV MK-III is yet another triumph of brilliance & hard work of our scientists. Congrats to them for the efforts."
K Radhakrishnan, chairman of the Indian Space and Research Organization (ISRO), said the launch marked a "very significant day in India's space history".
The rocket's main cargo was an Indian-made capsule capable of carrying two to three astronauts into space.
Geosynchronous Satellite Launch Vehicle (MK III) is India's heaviest rocket
ISRO said the capsule has "safely splashed down into Bay of Bengal off Andaman and Nicobar Islands" and that the experiment was successful.
ISRO has sought funding from the government to send its astronauts into space and the successful launch could be the first step towards boosting its claim, correspondents say.
India is emerging as a major player in the multi-billion dollar space market and has undertaken several missions. In September, it successfully put a satellite into orbit around Mars, becoming the fourth nation or geo-bloc to do so.
For more information about GSLV Mk-III X / CARE Mission and Indian Space Research Organisation (ISRO), visit: http://www.isro.org/
Images, Video, Text, Credits: ISRO/Orbiter.ch Aerospace.
Publié par Orbiter.ch à 17:17
NASA, Planetary Scientists Find Meteoritic Evidence of Mars Water Reservoir
December 19, 2014
NASA and an international team of planetary scientists have found evidence in meteorites on Earth that indicates Mars has a distinct and global reservoir of water or ice near its surface.
Though controversy still surrounds the origin, abundance and history of water on Mars, this discovery helps resolve the question of where the “missing Martian water” may have gone. Scientists continue to study the planet’s historical record, trying to understand the apparent shift from an early wet and warm climate to today’s dry and cool surface conditions.
The reservoir’s existence also may be a key to understanding climate history and the potential for life on Mars. The team’s findings are reported in the journal Earth and Planetary Science Letters.
Image above: This illustration depicts Martian water reservoirs. Recent research provides evidence for the existence of a third reservoir that is intermediate in isotopic composition between the Red Planet’s mantle and its current atmosphere. These results support the hypothesis that a buried cryosphere accounts for a large part of the initial water budget of Mars. Image Credit: NASA.
“There have been hints of a third planetary water reservoir in previous studies of Martian meteorites, but our new data require the existence of a water or ice reservoir that also appears to have exchanged with a diverse set of Martian samples,” said Tomohiro Usui of Tokyo Institute of Technology in Japan, lead author of the paper and a former NASA/Lunar and Planetary Institute postdoctoral fellow. “Until this study there was no direct evidence for this surface reservoir or interaction of it with rocks that have landed on Earth from the surface of Mars.”
Researchers from the Tokyo Institute of Technology, the Lunar and Planetary Institute in Houston, the Carnegie Institution for Science in Washington and NASA’s Astromaterials Research and Exploration Science Division, located at the agency’s Johnson Space Center in Houston, studied three Martian meteorites.
The samples revealed water comprised of hydrogen atoms that have a ratio of isotopes distinct from that found in water in the Red Planet’s mantle and current atmosphere. Isotopes are atoms of the same element with differing numbers of neutrons.
While recent orbiter missions have confirmed the presence of subsurface ice, and melting ground-ice is believed to have formed some geomorphologic features on Mars, this study used meteorites of different ages to show that significant ground water-ice may have existed relatively intact over time.
Researchers emphasize that the distinct hydrogen isotopic signature of the water reservoir must be of sufficient size that it has not reached isotopic equilibrium with the atmosphere.
“The hydrogen isotopic composition of the current atmosphere could be fixed by a quasi-steady-state process that involves rapid loss of hydrogen to space and the sublimation from a widespread ice layer,” said coauthor John Jones, a JSC experimental petrologist and member of NASA’s Mars Curiosity rover team.
Curiosity’s observations in a lakebed, in an area called Mount Sharp, indicate Mars lost its water in a gradual process over a significant period of time.
“In the absence of returned samples from Mars, this study emphasizes the importance of finding more Martian meteorites and continuing to study the ones we have with the ever-improving analytical techniques at our disposal,” said co-author Conel Alexander, a cosmochemist at the Carnegie Institution for Science.
In this investigation, scientists compared water, other volatile element concentrations and hydrogen isotopic compositions of glasses within the meteorites, which may have formed as the rocks erupted to the surface of Mars in ancient volcanic activity or by impact events that hit the Martian surface, knocking them off the planet.
“We examined two possibilities, that the signature for the newly identified hydrogen reservoir either reflects near surface ice interbedded with sediment or that it reflects hydrated rock near the top of the Martian crust,” said coauthor and JSC cosmochemist Justin Simon. “Both are possible, but the fact that the measurements with higher water concentrations appear uncorrelated with the concentrations of some of the other measured volatile elements, in particular chlorine, suggests the hydrogen reservoir likely existed as ice.”
Image above: Mars Rover's mockup comparison and dates the beginning of the missions: Mars Science Laboratory (R); Mars Exploration Rover (L) and Sojourner rover (centre). Image Credit: NASA/JPL-Caltech.
The information being gathered about Mars from studies on Earth, and data being returned from a fleet of robotic spacecraft and rovers on and around the Red Planet, are paving the way for future human missions on a journey to Mars in the 2030s.
These findings can be viewed online in their entirety at: http://go.nasa.gov/1zwSjTa
For more about the ARES Division at JSC, visit: http://ares.jsc.nasa.gov
Learn about NASA’s Journey to Mars at: http://www.nasa.gov/content/nasas-journey-to-mars/
Images (mentioned), Text, Credits: NASA/Dwayne Brown/Johnson Space Center/William Jeffs.
Best regards, Orbiter.ch
Publié par Orbiter.ch à 09:16
Hubble Sweeps a Messy Star Factory
NASA - Hubble Space Telescope patch.
December 19, 2014
This sprinkle of cosmic glitter is a blue compact dwarf galaxy known as Markarian 209. Galaxies of this type are blue-hued, compact in size, gas-rich, and low in heavy elements. They are often used by astronomers to study star formation, as their conditions are similar to those thought to exist in the early Universe.
Markarian 209 in particular has been studied extensively. It is filled with diffuse gas and peppered with star-forming regions towards its core. This image captures it undergoing a particularly dramatic burst of star formation, visible as the lighter blue cloudy region towards the top right of the galaxy. This clump is filled with very young and hot newborn stars.
This galaxy was initially thought to be a young galaxy undergoing its very first episode of star formation, but later research showed that Markarian 209 is actually very old, with an almost continuous history of forming new stars. It is thought to have never had a dormant period — a period during which no stars were formed — lasting longer than 100 million years.
The dominant population of stars in Markarian 209 is still quite young, in stellar terms, with ages of under 3 million years. For comparison, the sun is some 4.6 billion years old, and is roughly halfway through its expected lifespan.
Hubble and Sunrise over Earth
The observations used to make this image were taken using Hubble’s Wide Field Camera 3 and Advanced Camera for Surveys, and span the ultraviolet, visible, and infrared parts of the spectrum. A scattering of other bright galaxies can be seen across the frame, including the bright golden oval that could, due to a trick of perspective, be mistaken as part of Markarian 209 but is in fact a background galaxy.
ESA and NASA Hubble websites: http://www.spacetelescope.org/ and http://hubblesite.org/
Image, Video, Credits: ESA/Hubble & NASA Acknowledgement: Nick Rose.
Publié par Orbiter.ch à 08:48
jeudi 18 décembre 2014
Arianespace’s third Soyuz mission at the service of O3b Networks launch success!
Arianespace - Flight VS10 - O3b Networks poster.
December 18, 2014
Soyuz carrying four O3b Networks satellites liftoff
Soyuz liftoff at – 3:37 p.m. local time in French Guiana – initiating a flight sequence at last 2 hr., 22 min. Produced by Thales Alenia Space, the four O3b Networks satellites weigh approximately 700 kg. each and are to operate in medium Earth orbit (MEO).
Soyuz lifts off on Arianespace’s third flight at the service of O3b Networks
Payload lift performance for this flight is approximately 3,180 kg., including about 2,800 kg. for the four Ka-band satellites, which were produced by Thales Alenia Space for O3b Networks.
The O3b Networks Ka-band relay platforms are produced by Thales Alenia Space, creating a constellation for telecommunications and Internet services that combine high speed and affordable costs for billions of people across the world who do not yet have adequate internet access.
Soyuz flight VS10 carrying four O3b Networks satellites booster's separation
O3b Networks’ satellites operate at a medium Earth orbit (MEO) of 8,062 km., significantly reducing the round-trip data transmission times when compared to telecommunications satellites in geosynchronous Earth orbit (GEO) at 36,000 km.
Repositioning before release the second pair of O3b Networks’ satellites
This December 18 mission is designated VS10 in Arianespace’s numbering system, and be performed from the purpose-built ELS launch facility for Soyuz – which is located in the Spaceport’s northwestern sector.
The previous two Arianespace Soyuz missions for O3b Networks also lofted four spacecraft each on launches performed in July 2014 and June 2013 – enabling the company to deliver connectivity that combines the reach of satellite with the speed of fiber, providing customers with affordable, low latency, high bandwidth connectivity.
O3b Networks’ satellites
Flight VS10 will be Arianespace’s 11th mission overall in 2014, as well as its 10th Soyuz launch performed from French Guiana since the workhorse Russian-built vehicle’s 2011 introduction at the Spaceport.
O3b Networks website: http://www.o3bnetworks.com/homepage.aspx
Thales Alenia Space website: http://www.thalesgroup.com/space
For more information about Arianespace, visit: http://www.arianespace.com/index/index.asp
Images, Video, Text, Credit: Arianespace /Screen captures: Orbiter.ch Aerospace.
Publié par Orbiter.ch à 15:35
Origin of high-latitude auroras revealed
ESA - Cluster II Mission patch.
18 December 2014
Auroras are the most visible manifestation of the Sun’s effect on Earth, but many aspects of these spectacular displays are still poorly understood. Thanks to ESA’s Cluster and NASA’s Image satellites working together, a particular type of very high-latitude aurora has now been explained.
Although separated by some 150 million kilometres, the Sun and Earth are connected by the solar wind. This stream of plasma – electrically charged atomic particles – is launched by the Sun and travels across the Solar System, carrying its own magnetic field with it.
Cluster and Image during aurora observation
Depending on how this ‘interplanetary magnetic field’ is aligned with Earth’s magnetic field when it arrives, there can be various results.
At the point where the two fields meet, Earth’s magnetic field points north. If the interplanetary field is pointing south, then ‘magnetic reconnection’ can occur, where magnetic field lines pointing in opposite directions spontaneously break and reconnect with other nearby field lines.
This opens the door to solar wind plasma entering the magnetosphere – Earth’s magnetic ‘bubble’.
The ultimate result can be colourful displays in the night sky known as the Northern or Southern Lights, produced when the particles are channelled along Earth’s magnetic field lines and strike atoms high in the atmosphere.
Formation of a theta aurora
The interaction with oxygen atoms results in a green or, more rarely, red glow in the night sky, while nitrogen atoms yield blue and purple colours.
Normally, the main region for this impressive display is the ‘auroral oval’, which lies at around 65–70 degrees north or south of the equator, encircling the polar caps.
But when the interplanetary magnetic field points northward, auroras can occur at even higher latitudes. One type is known as a ‘theta aurora’ because seen from above it looks like the Greek letter theta – an oval with a line crossing through the centre.
While the genesis of the auroral oval emissions is reasonably well understood, the origin of the theta aurora was unclear until now.
A clue comes from the particles observed in the two ‘lobe’ regions of the magnetosphere. The plasma in the lobes is normally cold, but previous observations suggested that theta auroras are linked with unusually hot lobe plasma, though quite how was unclear.
Theta aurora as seen by NASA’s Image satellite on 15 September 2005
“The possibilities have been debated since the first satellite observations of the phenomenon were made in the 1980s,” describes Robert Fear of the University of Southampton in the UK (formerly at the University of Leicester), and lead author of the paper reporting the results inSciencethis week.
“Previously it was unclear whether this hot plasma was a result of direct solar wind entry through the lobes of the magnetosphere, or if the plasma is somehow related to the plasma sheet on the night side of Earth.
“One idea is that the process of magnetic reconnection on the night side of Earth causes a build-up of ‘trapped’ hot plasma in the higher latitude lobes.”
The mystery was finally solved by studying data collected simultaneously by the Cluster and Image satellites on 15 September 2005. While the four Cluster satellites were located in the southern hemisphere magnetic lobe, Image had a wide-field view of the southern hemisphere aurora. As one Cluster satellite observed uncharacteristically energetic plasma in the lobe, Image saw the ‘arc’ of the theta aurora cross the magnetic footprint of Cluster.
“We found that the energetic plasma signatures occur on high-latitude magnetic field lines that have been ‘closed’ by the process of magnetic reconnection, which then causes the plasma to become relatively hot,” says Dr Fear.
The Cluster quartet
“Because the field lines are closed, the observations are incompatible with direct entry from the solar wind. By testing this and other predictions about the behaviour of the theta aurora, our observations provide strong evidence that the plasma trapping mechanism is responsible for the theta aurora.”
“The study highlights the intriguing process that can occur in the magnetosphere when the interplanetary magnetic field of the solar wind points northwards,” adds Philippe Escoubet, ESA’s Cluster project scientist.
“This is the first time that the origin of the theta aurora phenomenon has been revealed, and it is thanks to localised measurements from Cluster combined with the wide-field view of Image that we can better understand another aspect of the Sun–Earth connection.”
Notes for Editors:
“Direct observation of closed magnetic flux trapped in the high latitude magnetosphere” by R. Fear et al. is published inScience, 19 December 2014.
ESA’s Cluster consists of four satellites flying in formation around Earth. The data presented in this report were collected by Cluster-1. The Cluster mission was launched in 2000 and is still operating.
NASA’s Imager for Magnetopause-to-Aurora Global Exploration satellite was launched in 2000 and concluded operations at the end of 2005. The data presented in this report were collected by the satellite’s far-ultraviolet Wideband Imaging Camera.
Cluster brochure: http://download.esa.int/multimedia/publications/BR-290/BR-290_CLUSTER%202000_10_05sp.pdf
Cluster overview: http://www.esa.int/Our_Activities/Space_Science/Cluster_overview2
The magnetosphere: http://www-ssc.igpp.ucla.edu/personnel/russell/papers/magsphere/
Cluster Wave Experiment Consortium (CWEC): http://www.plasma.kth.se/cluster/wec.html
Magnetic reconnection: http://clusterlaunch.esa.int/science-e/www/object/index.cfm?fobjectid=36452
Cluster Science Data System: http://sci2.estec.esa.nl/cluster/csds/csds.html
Cluster II Joint Science Operations Centre (JSOC): http://www.jsoc.rl.ac.uk/
Cluster in-depth: http://sci.esa.int/science-e/www/area/index.cfm?fareaid=8
Images, Video, Text, Credits: ESA/NASA/SOHO/LASCO/EIT/NASA/R. Fear et al (2014).
Publié par Orbiter.ch à 14:25
NASA’s Kepler Reborn, Makes First Exoplanet Find of New Mission
NASA - Kepler Mission patch.
December 18, 2014
NASA's planet-hunting Kepler spacecraft makes a comeback with the discovery of the first exoplanet found using its new mission -- K2.
The discovery was made when astronomers and engineers devised an ingenious way to repurpose Kepler for the K2 mission and continue its search of the cosmos for other worlds.
Image above: The artistic concept shows NASA's planet-hunting Kepler spacecraft operating in a new mission profile called K2. Using publicly available data, astronomers have confirmed K2's first exoplanet discovery proving Kepler can still find planets. Image Credit: NASA Ames/JPL-Caltech/T Pyle.
"Last summer, the possibility of a scientifically productive mission for Kepler after its reaction wheel failure in its extended mission was not part of the conversation," said Paul Hertz, NASA's astrophysics division director at the agency's headquarters in Washington. "Today, thanks to an innovative idea and lots of hard work by the NASA and Ball Aerospace team, Kepler may well deliver the first candidates for follow-up study by the James Webb Space Telescope to characterize the atmospheres of distant worlds and search for signatures of life."
Lead researcher Andrew Vanderburg, a graduate student at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, studied publicly available data collected by the spacecraft during a test of K2 in February 2014. The discovery was confirmed with measurements taken by the HARPS-North spectrograph of the Telescopio Nazionale Galileo in the Canary Islands, which captured the wobble of the star caused by the planet’s gravitational tug as it orbits.
The newly confirmed planet, HIP 116454b, is 2.5 times the diameter of Earth and follows a close, nine-day orbit around a star that is smaller and cooler than our sun, making the planet too hot for life as we know it. HIP 116454b and its star are 180 light-years from Earth, toward the constellation Pisces.
Artist's conception of HIP 116454b. Image Credit: NASA/JPL-Caltech
Kepler’s onboard camera detects planets by looking for transits -- when a distant star dims slightly as a planet crosses in front of it. The smaller the planet, the weaker the dimming, so brightness measurements must be exquisitely precise. To enable that precision, the spacecraft must maintain steady pointing. In May 2013, data collection during Kepler's extended prime mission came to an end with the failure of the second of four reaction wheels, which are used to stabilize the spacecraft.
Rather than giving up on the stalwart spacecraft, a team of scientists and engineers crafted a resourceful strategy to use pressure from sunlight as a “virtual reaction wheel” to help control the spacecraft. The resulting K2 mission promises to not only continue Kepler’s planet hunt, but also to expand the search to bright nearby stars that harbor planets that can be studied in detail and better understand their composition. K2 also will introduce new opportunities to observe star clusters, active galaxies and supernovae.
Small planets like HIP 116454b, orbiting nearby bright stars, are a scientific sweet spot for K2 as they are good prospects for follow-up ground studies to obtain mass measurements. Using K2’s size measurements and ground-based mass measurements, astronomers can calculate the density of a planet to determine whether it is likely a rocky, watery or gaseous world.
"The Kepler mission showed us that planets larger in size than Earth and smaller than Neptune are common in the galaxy, yet they are absent in our solar system," said Steve Howell, Kepler/K2 project scientist at NASA's Ames Research Center in Moffett Field, California. "K2 is uniquely positioned to dramatically refine our understanding of these alien worlds and further define the boundary between rocky worlds like Earth and ice giants like Neptune."
Since the K2 mission officially began in May 2014, it has observed more than 35,000 stars and collected data on star clusters, dense star-forming regions, and several planetary objects within our own solar system. It is currently in its third campaign.
The research paper reporting this discovery has been accepted for publication in The Astrophysical Journal.
Ames is responsible for Kepler's mission concept, ground system development, science data analysis and K2 mission operations. NASA's Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corp. in Boulder, Colorado, developed the Kepler flight system and supports mission operations with the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. The Space Telescope Science Institute in Baltimore archives, hosts and distributes Kepler science data. Kepler is NASA's 10th Discovery Mission and was funded by the agency's Science Mission Directorate in Washington.
For more information about the Kepler mission, visit: http://www.nasa.gov/kepler
Images (mentioned), Text, Credits: NASA/Felicia Chou/Ames Research Center/Michele Johnson.
Publié par Orbiter.ch à 10:17
NASA’s Chandra Weighs Most Massive Galaxy Cluster in Distant Universe
NASA - Chandra X-ray Observatory patch.
December 18, 2014
A newly discovered galaxy cluster is the most massive one ever detected with an age of 800 million years or younger. Using data from NASA’s Chandra X-ray Observatory, astronomers have accurately determined the mass and other properties of this cluster, as described in our latest press release. This is an important step in understanding how galaxy clusters, the largest structures in the Universe held together by gravity, have evolved over time.
Image above: A Chandra composite image shows the distant and massive galaxy cluster that is officially known as XDCP J0044.0-2033. Image Credit: X-ray: NASA/CXC/INAF/P. Tozzi, et al; Optical: NAOJ/Subaru a.
A composite image shows the distant and massive galaxy cluster that is officially known as XDCP J0044.0-2033. Researchers, however, have nicknamed it “Gioiello”, which is Italian for “jewel”. They chose this name because an image of the cluster contains many sparkling colors from the hot, X-ray emitting gas and various star-forming galaxies within the cluster. Also, the research team met to discuss the Chandra data for the first time at Villa il Gioiello, a 15th century villa near the Observatory of Arcetri, which was the last residence of prominent Italian astronomer Galileo Galilei. In this new image of the Gioiello Cluster, X-rays from Chandra are purple, infrared data from ESA’s Hershel Space Telescope appear as large red halos around some galaxies, and optical data from the Subaru telescope on Mauna Kea in Hawaii are red, green, and blue.
Astronomers first detected the Gioiello Cluster, located about 9.6 billion light years away, using ESA’s XMM-Newton observatory. They were then approved to study the cluster with Chandra in observations that were equivalent to over four days of time. This is the deepest X-ray observation yet made on a cluster beyond a distance of about 8 billion light years.
The long observing time allowed the researchers to gather enough X-ray data from Chandra that, when combined with scientific models, provides an accurate weight of the cluster. They determined that the Gioiello Cluster contains a whopping 400 trillion times the mass of the Sun.
Chandra X-ray Observatory spacecraft. Image Credits: NASA/CXC
Previously, astronomers had found an enormous galaxy cluster, known as “El Gordo,” at a distance of 7 billion light years away and a few other large, distant clusters. According to the best current model for how the Universe evolved, there is a low chance of finding clusters as massive as the Gioiello Cluster and El Gordo. The new findings suggest that there might be problems with the theory, and are enticing astronomers to look for other distant and massive clusters.
These results are being published in The Astrophysical Journal. The first author is Paolo Tozzi, from the National Institute for Astrophysics (INAF) in Florence, Italy. The co-authors are Johana Santos, also from INAF in Florence, Italy;
James Jee from the University of California in Davis; Rene Fassbender from INAD in Rome, Italy; Piero Rosati from the University of Ferrara in Ferrara, Italy; Alessandro Nastasi from the University of Paris-Sud, in Orsay, France; William Forman from Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge; MA; Barbara Sartoris and Stefano Borgani from the University of Trieste in Trieste, Italy; Hans Boehringer from the Max Planck Institute for Astrophysics in Garching, Germany; Bruno Altieri from the European Space Agency in Madrid, Spain; Gabriel Pratt from CEA Saclay in Cedex, France; Mario Nonino from the University of Trieste in Trieste, Italy and Christine Jones from CfA.
NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Mass., controls Chandra's science and flight operations.
For an additional interactive image, podcast, and video on the finding, visit: http://chandra.si.edu
For Chandra images, multimedia and related materials, visit: http://www.nasa.gov/chandra
Images (mentioned), Text, Credits: NASA/Marshall Space Flight Center/Janet Anderson/Chandra X-ray Center/Megan Watzke.
Publié par Orbiter.ch à 10:04
Preparing for an asteroid strike
Asteroid & Comet Watch logo.
18 December 2014
ESA and national disaster response offices recently rehearsed how to react if a threatening space rock is ever discovered to be on a collision course with Earth.
Last month, experts from ESA’s Space Situational Awareness (SSA) programme and Europe’s national disaster response organisations met for a two-day exercise on what to do if an asteroid is ever found to be heading our way.
Trace of an Alien visitor
Image above: Chelyabinsk asteroid trail. Image Credits: Alex Alishevskikh CC BY-SA 2.0 via http://www.flickr.com/photos/alexeya/.
In ESA’s first-ever asteroid impact exercise, they went through a countdown to an impact, practising steps to be taken if near-Earth objects, or NEOs, of various sizes were detected.
The exercise considered the threat from an imaginary, but plausible, asteroid, initially thought to range in size from 12 m to 38 m – spanning roughly the range between the 2013 Chelyabinsk airburst and the 1908 Tunguska event – and travelling at 12.5 km/s.
Critical times to take action
Teams were challenged to decide what should happen at five critical points in time, focused on 30, 26, 5 and 3 days before and 1 hour after impact.
“There are a large number of variables to consider in predicting the effects and damage from any asteroid impact, making simulations such as these very complex,” says Detlef Koschny, head of NEO activities in the SSA office.
“These include the size, mass, speed, composition and impact angle. Nonetheless, this shouldn’t stop Europe from developing a comprehensive set of measures that could be taken by national civil authorities, which can be general enough to accommodate a range of possible effects.
“The first step is to study NEOs and their impact effects and understand the basic science.”
How should Europe react
Participants came from various departments and agencies of the ESA member states Germany and Switzerland, including Germany’s Federal Office of Civil Protection and Disaster Assista.
They studied questions such as: how should Europe react, who would need to know, which information would need to be distributed, and to whom?
“For example, within about three days before a predicted impact, we’d likely have relatively good estimates of the mass, size, composition and impact location,” says Gerhard Drolshagen of ESA’s NEO team.
“All of these directly affect the type of impact effects, amount of energy to be generated and hence potential reactions that civil authorities could take.”
Chelyabinsk: injuries due to overpressure
During the 2013 Chelyabinsk event, for instance, the asteroid, with a mass of about 12 000 tonnes and a size of 19 m, hit the upper atmosphere at a shallow angle and a speed of about 18.6 km/s, exploding with the energy of 480 kilotons of TNT at an altitude of 25–30 km.
While potentially a real hazard, no injuries due to falling fragments were reported. Instead, more than 1500 people were injured and 7300 buildings damaged by the intense overpressure generated by the shockwave at Earth’s surface.
Many people were injured by shards of flying glass as they peered out of windows to see what was happening.
SSA-NEO Coordination Centre ESRIN
“In such a case, an appropriate warning by civil authorities would include simply telling people to stay away from windows, and remain within the strongest portions of a building, such as the cellar, similar to standard practice during tornados in the USA,” says Gerhard.
In a real strike, ESA’s role would be crucial. It will have to warn both civil protection authorities and decision-makers about the impact location and time. It would also have to share reliable scientific data, including possible impact effects, and provide trustworthy and authoritative information.
Estabishing internationally coordinated procedures
The exercise ended on 25 November, a significant step forward at highlighting the unique factors in emergency planning for asteroid strikes, and possible courses of action. It also clarified a number of open points, including requirements from civil protection agencies and the type and time sequence of information that can be provided by ESA’s SSA.
It is another step in the continuing effort to set up an internationally coordinated procedure for information distribution and potential mitigation actions in case of an imminent threat.
ESA’s NEO team is also working with international partners, agencies and organisations, including the UN, to help coordinate a global response to any future impact threat (see "Getting ready for asteroids" http://www.esa.int/Our_Activities/Operations/Space_Situational_Awareness/Getting_ready_for_asteroids).
With the aim of strengthening ESA’s and Europe’s response, similar exercises will be held in the future. The next, in 2015, will include representatives from additional countries.
Minor Planet Center: http://www.minorplanetcenter.org/iau/mpc.html
Spaceguard Central Node: http://spaceguard.rm.iasf.cnr.it/
European Asteroid Research Node: http://earn.dlr.de/
Near-Earth Objects - Dynamic Site: http://newton.dm.unipi.it/neodys/
UK Spaceguard Centre: http://www.spaceguarduk.com/
NASA NEO Office: http://neo.jpl.nasa.gov/
NEO mission studies: http://www.esa.int/Our_Activities/Space_Engineering_Technology/NEO
Torino impact hazard scale: http://neo.jpl.nasa.gov/torino_scale.html
Palermo Technical Impact Hazard Scale: http://neo.jpl.nasa.gov/risk/doc/palermo.html
Images, Text, Credits: ESA/P.Carril.
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Publié par Orbiter.ch à 07:40
ESA - SMOS Mission logo.
18 December 2014
Measurements of salt held in surface seawater are becoming ever-more important for us to understand ocean circulation and Earth’s water cycle. ESA’s SMOS mission is proving essential to the quest.
The Soil Moisture and Ocean Salinity satellite, SMOS, is monitoring changes in the amount of water held in the surface layers of soil and concentrations of salt in the top layer of seawater – both of which are a consequence of the continuous exchange of water between the oceans, the atmosphere and the land.
Five years of global sea-surface salinity from space
Launched in 2009, SMOS has provided the longest continuous record of sea-surface salinity measurements from space.
The salinity of surface seawater is controlled largely by the balance between evaporation and precipitation, but fresh water from rivers and the freezing and melting of ice also changes the concentrations.
Along with temperature, salinity drives ocean circulation, which, in turn, plays a key role in the global climate.
With a wealth of salinity data from SMOS now in hand complemented by measurements from the US–Argentinian Aquarius satellite, which uses a different technique, scientists gathered recently at the UK Met Office to review the benefits this has brought to science.
Sea-surface salinity and ocean circulation
Speaking at the Ocean Salinity Science and Salinity Remote-Sensing Workshop, Prof. Dame Julia Slingo, Met Office Chief Scientist, said, “We need to understand the role of salinity in the closure of the hydrology cycle – arguably the weakest point in global climate modelling.
“Salinity, and particularly sea-surface salinity, is a challenging but important topic for ocean circulation and climate variability about which we need to know more, especially given the recent climate-warming hiatus.
“The SMOS mission, now celebrating five years in orbit, is providing detailed global measurements of ocean-surface salinity that are now used to address some of these challenges.”
The animation above shows variations in 10-day mean sea-surface salinity using five years of SMOS data.
Nicolas Reul from the French Research Institute for the Exploitation of the Sea, Ifremer, said, “Using SMOS salinity data we have been able to determine and monitor for the first time from space an ensemble of key ocean processes for climate and biochemistry.
SMOS in orbit
“This includes, for example, the detailed salinity structure of tropical instability waves along the equator and the salt exchanged across major oceanic current fronts through energetic ocean rings.
“Occurrences of large-scale salinity anomalies in the Pacific and Indian oceans related to El Niño, La Niña and the Indian Ocean climate were also well-evidenced in the five year-long data.
“In addition, the dispersal of freshwater into the ocean from the major large tropical rivers, namely the Amazon, Orinoco and Congo Rivers, their impact on tropical cyclone intensification and the oceanic imprints of the intense rainfall in the Trade Wind convergence zones can now be regularly monitored to better understand the variability of the oceanic part of the global water cycle.”
Numerous case studies were discussed at the workshop, including results from the ‘SMOS+ Surface Ocean Salinity’ project.
Traditional physical oceanography process studies are now also being addressed using remote sensing.
Roberto Sabia, Earth observation data engineer at ESA, said, “By using SMOS measurements, we are now able to generate surface temperature-salinity diagrams, and relate salinity dynamics with water density.
Understanding the ocean
“Armed with this tool, we are now working towards routinely identifying areas where specific surface-water masses form – water bodies with physical properties distinct from the surrounding water – directly linking satellite measurements of sea-surface salinity with air–sea fluxes and ocean circulation.”
ESA’s Craig Donlon said “SMOS data, along with concurrent in situ Argo ocean-profile data, other satellite observations of sea-surface temperature, sea-surface height, surface-wind stress and ocean colour, are now providing new opportunities to investigate the surface and subsurface ocean mesoscale dynamics.
“Using these different measurements together is the key to yielding further scientific insight into the water cycle.”
Ocean Salinity Science and Salinity Remote-Sensing Workshop: http://www.oceansalinityscience2014.org/
Sea-surface salinity remote sensing: http://www.salinityremotesensing.ifremer.fr/
Barcelona Expert Centre: http://www.smos-bec.icm.csic.es/
Met Office–research: http://www.metoffice.gov.uk/research
Support to Science Element: http://due.esrin.esa.int/stse/
Access SMOS data: http://earth.esa.int/SMOS/
SMOS-based ocean surface T-S: http://onlinelibrary.wiley.com/enhanced/doi/10.1002/2014JC010120/
2nd SMOS science conference: http://www.smos2015.info/
Images, Video, Text, Credits: ESA/Ifremer/N. Reul/AOES Medialab/R. Kirby.
Publié par Orbiter.ch à 07:26
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