vendredi 7 mars 2014

Station Crew Preps for Return to Earth, Repairs Recycling System













ISS - Expedition 38 Mission patch.

March 7, 2014

With less than five days left before half the crew aboard the International Space Station departs, the six astronauts and cosmonauts of Expedition 38 performed maintenance on station systems, conducted research and packed items for the journey back to Earth.

Following the crew’s daily planning conference with the flight control teams around the world, Flight Engineer Mike Hopkins went to work in the station’s Tranquility node to begin the removal and replacement of a catalytic reactor inside the Water Recovery System. Hopkins temporarily removed the COLBERT treadmill and rotated the large, refrigerator-sized rack that houses the recycling system to gain access to the connections at the front and back of the rack. Flight Engineer Rick Mastracchio then joined Hopkins to help remove the old catalytic reactor and install a new one. The two NASA astronauts also installed a temporary filter between the reactor and the microbial check valve to support a system flush of the replacement unit. Part of the station’s Environment Control and Life Support System, the Water Recovery System recycles condensation and urine into drinkable water.


Image above: Expedition 38 crew members pose for an in-flight crew portrait in the Kibo laboratory of the International Space Station. Image Credit: NASA.

Afterward, Hopkins rotated the Water Recovery System back into place, reinstalled the treadmill and removed the temporary filter. Mastracchio meanwhile inspected the failed catalytic reactor and packaged it up for return to Earth.

Mastracchio also spent some time installing video hardware for the ham radio located in the Columbus module. He performed a quick test of the hardware to verify basic functionality. A full test to commission the new system is scheduled for Saturday.


Image above: This grand panorama of the Southern Patagonia Icefield (center) was imaged by an Expedition 38 crew member on the International Space Station on one of the rare clear days in the southern Andes Mountains. Image Credit: NASA.

Flight Engineer Koichi Wakata spent much of the day working in the Kibo laboratory. The Japan Aerospace Exploration Agency astronaut first checked in on the Space Midge experiment, observing the progress of insects that he rehydrated two weeks ago. Larvae of the sleeping chironomid, a kind of midge native to semiarid regions of Africa, are able to withstand nearly complete desiccation. Researchers are studying this midge to examine the impact of desiccation tolerance in a space environment as well as gene expression in response to microgravity.


Flight Engineer Koichi Wakata gathers up packing foam in the Kibo module as he sets up the Marangoni experiment for its next phase of operations. Image Credit: NASA TV.

Later, Wakata continued preparing the Fluid Physics Experiment Facility for the next phase of the Marangoni experiment. The Japanese astronaut carefully cleaned contamination from the facility’s mirrors and replaced experiment hardware. Marangoni convection is the flow process that results from the difference in surface tensions where a liquid and a gas come together. By studying this process in microgravity, researchers hope to uncover fundamental properties that could improve the production of semiconductors and optical crystals and contribute to various micro-fluid handling techniques, such as those used in DNA examination and clinical diagnostics.

Read more about the Marangoni experiment: http://www.nasa.gov/mission_pages/station/research/experiments/272.html

On the Russian side of the complex, Commander Oleg Kotov and Flight Engineer Sergey Ryazanskiy focused their attention on their return to Earth Monday night along with Hopkins aboard the Soyuz TMA-10M spacecraft.

International Space Station (ISS). Image Credit: NASA

Kotov and Ryazanskiy spent much of the day packing science cargo, hardware and personal items for the trip home aboard the Soyuz. The third Russian cosmonaut aboard the station, Flight Engineer Mikhail Tyurin, assisted his crewmates as he transferred Biorisk experiment hardware and Matryoshka radiation detectors into the Soyuz.

To prepare themselves for the return to Earth’s gravity after 166 days in space, Kotov and Ryazanskiy each participated in Lower Body Negative Pressure tests by exercising while wearing a special outfit that simulates the effects of gravity by drawing fluids to the lower half of the body. In addition to conditioning cosmonauts for the return home, this device provides Russian researchers with data to predict how the cosmonauts will react to the full force of Earth’s gravity at the end of their mission.

On Monday, Kotov, Hopkins and Ryazanskiy will bid farewell to their fellow crewmates and board their Soyuz, closing the hatches at 4:45 p.m. EDT. The trio will undock from the station at 8:02 p.m. and land southeast of the town of Dzhezkazgan in Kazakhstan at 11:24 p.m. (9:24 a.m. Tuesday, Kazakhstan time).


Image above: At the Gagarin Cosmonaut Training Center in Star City, Russia and with the visage of Yuri Gagarin, the first human to fly in space, looking down on them, the Expedition 39/40 crew fields questions from reporters March 5 prior to qualification exams. Image Credit: NASA.

The departure of Kotov, Hopkins and Ryazanskiy on Monday will mark the end of Expedition 38 and the beginning of Expedition 39 under the leadership of Wakata, the first Japan Aerospace Exploration Agency astronaut to command the station. Kotov will pass the helm to Wakata during a Change of Command ceremony slated for 5 a.m. Sunday. Wakata, Mastracchio and Tyurin, who arrived at the orbiting complex Nov. 7, will remain aboard the station until mid-May.

Meanwhile the three flight engineers who will return the station’s crew to its full six-person complement are in the homestretch of preparations for launch on March 25. Having completed the second of two days of final qualification exams Wednesday, NASA astronaut Steve Swanson and Russian cosmonauts Alexander Skvortsov and Oleg Artemyev conducted a pre-launch news conference at the Gagarin Cosmonaut Training Center in Star City, Russia. Their back-ups, NASA astronaut Barry Wilmore and cosmonauts Elena Serova and Alexander Samokutyaev, joined them for the conference and traveled with them to Moscow’s Red Square to lay flowers at the Kremlin Wall in honor of the Russian space icons interred there.

View latest photos of Expedition 39 crew training: http://www.nasa.gov/mission_pages/station/expeditions/expedition39/gallery.html

Read more about Expedition 39: http://www.nasa.gov/mission_pages/station/expeditions/expedition39/index.html

For more information about the Intenational Space Station (ISS), visit: http://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Text, Credit: NASA.

Greetings, Orbiter.ch

NASA's WISE Survey Finds Thousands of New Stars, But No 'Planet X'







NASA - WISE Mission logo.

March 7, 2014


Image above: A nearby star stands out in red in this image from the Second Generation Digitized Sky Survey. Image Credit: DSS/NASA/JPL-Caltech.

After searching hundreds of millions of objects across our sky, NASA's Wide-Field Infrared Survey Explorer (WISE) has turned up no evidence of the hypothesized celestial body in our solar system commonly dubbed "Planet X."

Researchers previously had theorized about the existence of this large, but unseen celestial body, suspected to lie somewhere beyond the orbit of Pluto. In addition to "Planet X," the body had garnered other nicknames, including "Nemesis" and "Tyche."

This recent study, which involved an examination of WISE data covering the entire sky in infrared light, found no object the size of Saturn or larger exists out to a distance of 10,000 astronomical units (au), and no object larger than Jupiter exists out to 26,000 au. One astronomical unit equals 93 million miles. Earth is 1 au, and Pluto about 40 au, from the sun.

"The outer solar system probably does not contain a large gas giant planet, or a small, companion star," said Kevin Luhman of the Center for Exoplanets and Habitable Worlds at Penn State University, University Park, Pa., author of a paper in the Astrophysical Journal describing the results.

But searches of the WISE catalog are not coming up empty. A second study reveals several thousand new residents in our sun's "backyard," consisting of stars and cool bodies called brown dwarfs.


Image above: Data from NASA's Wide-field Infrared Survey Explorer, or WISE, has found no evidence for a hypothesized body sometimes referred to as "Planet X." Image Credit: Penn State University.

"Neighboring star systems that have been hiding in plain sight just jump out in the WISE data," said Ned Wright of the University of California, Los Angeles, the principal investigator of the mission.

The second WISE study, which concentrated on objects beyond our solar system, found 3,525 stars and brown dwarfs within 500 light-years of our sun.

"We're finding objects that were totally overlooked before," said Davy Kirkpatrick of NASA's Infrared and Processing Analysis Center at the California Institute of Technology, Pasadena, Calif. Kirkpatrick is lead author of the second paper, also in the Astrophysical Journal. Some of these 3,525 objects also were found in the Luhman study, which catalogued 762 objects.

The WISE mission operated from 2010 through early 2011, during which time it performed two full scans of the sky -- with essentially a six-month gap between scans. The survey captured images of nearly 750 million asteroids, stars and galaxies. In November 2013, NASA released data from the AllWISE program, which now enables astronomers to compare the two full-sky surveys to look for moving objects.

In general, the more an object in the WISE images appears to move over time, the closer it is. This visual clue is the same effect at work when one observes a plane flying low to the ground versus the same plane flying at higher altitude. Though traveling at the same speed, the plane at higher altitude will appear to be moving more slowly.

Searches of the WISE data catalog for these moving objects are uncovering some of the closest stars. The discoveries include a star located about 20 light-years away in the constellation Norma, and as reported last March, a pair of brown dwarfs only 6.5 light-years away -- making it the closest star system to be discovered in nearly a century.


Image above: The third closest star system to the sun, called WISE J104915.57-531906, is at the center of the larger image, which was taken by NASA's Wide-field Infrared Survey Explorer (WISE). Image Credit: NASA/JPL/Gemini Observatory/AURA/NSF.

Despite the large number of new solar neighbors found by WISE, "Planet X" did not show up. Previous speculations about this hypothesized body stemmed in part from geological studies that suggested a regular timing associated with mass extinctions on Earth. The idea was that a large planet or small star hidden in the farthest reaches of our solar system might periodically sweep through bands of outer comets, sending them flying toward our planet. The Planet X-based mass extinction theories were largely ruled out even prior to the new WISE study.

Other theories based on irregular comet orbits had also postulated a Planet X-type body. The new WISE study now argues against these theories as well.

Both of the WISE searches were able to find objects the other missed, suggesting many other celestial bodies likely await discovery in the WISE data.

"We think there are even more stars out there left to find with WISE. We don't know our own sun's backyard as well as you might think," said Wright.

NASA's Wide-field Infrared Survey Explorer (WISE). Image credit: NASA/JPL-Caltech

WISE was put into hibernation upon completing its primary mission in 2011. In September 2013, it was reactivated, renamed NEOWISE and assigned a new mission to assist NASA's efforts to identify the population of potentially hazardous near-Earth objects. NEOWISE will also characterize previously known asteroids and comets to better understand their sizes and compositions.

JPL managed and operated WISE for NASA's Science Mission Directorate. The mission was selected competitively under NASA's Explorers Program managed by the agency's Goddard Space Flight Center in Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory in Logan, Utah. The spacecraft was built by Ball Aerospace & Technologies Corp. in Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. More information is online at: http://www.nasa.gov/wise and http://wise.astro.ucla.edu and http://jpl.nasa.gov/wise.

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

Best regards, Orbiter.ch

Kepler Team Marks Five Years in Space












NASA - Kepler Mission patch.

March 07, 2014

Liftoff of the Delta II rocket carrying the Kepler spacecraft. Image credit: NASA/Kim Shiflett

Exactly five years ago, on March 6, 2009, NASA's Kepler Space Telescope rocketed into the night skies above Cape Canaveral Air Force Station in Florida to find planets around other stars, called exoplanets, in search of potentially habitable worlds.

Since then, Kepler has unveiled a whole new side of our galaxy -- one that is teeming with planets. Because of Kepler, we now know that most stars have planets, Earth-sized planets are common, and planets quite unlike those in our solar system exist.

By analyzing Kepler data, scientists have identified more than 3,600 candidates believed to be planets, and verified that 961 of those candidates actually are planets, many as small as Earth. Discoveries made using Kepler now account for more than half of all the known exoplanets.

"In five years, Kepler has revolutionized our view of our place in the universe," said James Fanson, the former project manager for the mission at NASA's Jet Propulsion Laboratory in Pasadena, Calif., during development and launch. "Now we know Earth-sized planets are common across the galaxy."

NASA's Kepler Space Telescope. Image credit: NASA

Kepler's finds include planets that orbit in the habitable zone, the range of distances from a star where the surface temperature of an orbiting planet may be suitable for life-giving liquid water. One example of a habitable-zone planet found by the mission is known as Kepler-22b. At 2.4 times the size of Earth, it is thought to be too big to be rocky and support life. Scientists believe other habitable-zone planets found by the Kepler mission might be rocky, such as Kepler-62f, which is 40 percent larger in size than Earth.

A twin to Earth -- a planet with the same temperature and size as our planet -- has not yet been identified, but the analysis is far from over, as scientists continue to search the Kepler data for the tiny signature of such a planet.

Other Kepler discoveries include hundreds of star systems hosting multiple planets, and establishing a new class of planetary system where planets orbit more than one sun.

In search of potentially habitable worlds. Image credit: NASA

In August of last year, the mission ended its science observations after a faulty reaction wheel affected the telescope's ability to point precisely. The mission may be able to operate in a different mode and continue to do science. This next-generation mission proposal, called K2, will be considered for funding by NASA in the 2014 Astrophysics Senior Review of Operating Missions.

"Kepler really has reaped an amazing harvest of planets as well as other important and exciting results; much more than we had dared hope for," said Nick Gautier, the deputy project scientist for the mission at JPL. "Kepler has demonstrated that essentially every star has planets. This is a philosophical game changer for thinking about humanity's place in the universe."

NASA's Ames Research Center, Moffett Field, Calif., is responsible for the Kepler mission concept, ground system development, mission operations and science data analysis. NASA's Jet Propulsion Laboratory in Pasadena, Calif., managed Kepler mission development. Ball Aerospace & Technologies Corp. in Boulder, Colo., 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.

For more information about the Kepler space telescope, visit: http://www.nasa.gov/kepler

Images (mentioned), Text, Credits: NASA / JPL / Whitney Clavin / Ames Research Center / Michele Johnson.

Greetings, Orbiter.ch

jeudi 6 mars 2014

NASA's THEMIS Discovers New Process that Protects Earth from Space Weather









NASA - THEMIS Mission patch.

March 6, 2014

In the giant system that connects Earth to the sun, one key event happens over and over: solar material streams toward Earth and the giant magnetic bubble around Earth, the magnetosphere helps keep it at bay. The parameters, however, change: The particles streaming in could be from the constant solar wind, or perhaps from a giant cloud erupting off the sun called a coronal mass ejection, or CME. Sometimes the configuration is such that the magnetosphere blocks almost all the material, other times the connection is long and strong, allowing much material in. Understanding just what circumstances lead to what results is a key part of protecting our orbiting spacecraft from the effects of such space weather.


Animation above: NASA's THEMIS mission observed how dense particles normally near Earth in a layer of the uppermost atmosphere called the plasmasphere can send a plume up through space to help protect against incoming solar particles during certain space weather events. Image Credit: NASA/Goddard Space Flight Center.

Now, for the first time, a study shows that in certain circumstances a pool of dense particles normally circling Earth, deep inside the magnetosphere, can extend a long arm out to meet – and help block – incoming solar material.

"It’s like what you might do if a monster tried to break into your house. You’d stack furniture up against the front door, and that’s close to what the Earth is doing here," said Brian Walsh, a space scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "The material that is usually much nearer Earth stacks up against the outer boundary of the magnetosphere, throttling the interaction there and stopping solar material from entering."

In the March 6, 2014, issue of Science Express, Walsh and his colleagues compared observations from the ground and in space during a solar storm on Jan. 17, 2013. This was a fairly moderate solar storm caused by a CME impacting Earth's magnetosphere for several hours. As the CME encountered the boundary of the magnetosphere, its magnetic fields and those around Earth realigned in a process called magnetic reconnection, which allowed energy and solar material to cross the boundary into the magnetosphere. NASA's three THEMIS – for Time History of Events and Macroscale Interactions during Substorms – spacecraft were in the right place at the right time, flying through the magnetosphere's boundary approximately 45 minutes apart, and caught this interaction.


Image above: A thin layer of cold, dense material called the plasmasphere surrounds Earth. Researchers have found that material in the plasmasphere can help prevent particles from the sun crossing into near Earth space. Image Credit: NASA.

Closer to Earth, scientists could also study the sphere of cold dense gas at the very top of our atmosphere. This region is called the plasmasphere and it's made of what's known as plasma, a gas made of charged particles. GPS signals travel through the plasmasphere and they travel at different speeds depending on how thick or thin the plasmasphere is along the journey. Tracking the GPS radio signals, therefore, can help researchers map out the properties of the plasmasphere.

"A colleague who works with these kind of observations said I had to see some interesting data showing a plume from the ground," said Walsh. "And I typed in the dates and saw that it was a date when THEMIS was in the right position. So, for the first time, we could make a comparison."

THEMIS showed that the tongue of this cold, dense plasmasphere material stretched all the way up to the magnetic reconnection point where the CME had made contact with the magnetopause. The three sets of THEMIS observations demonstrated that the plume had a dramatic impact on the characteristics of the magnetic reconnection region.

"It wouldn't work if the magnetic reconnection happened for only a few minutes," said David Sibeck the project scientist for THEMIS at NASA Goddard. "But if it lasts long enough, the whole magnetosphere gets involved. This tongue of the plasmasphere surges out, adding another layer of protection, curbing the magnetic reconnection."


Image above: Artist's rendition of the THEMIS spacecraft in orbit in Earth's magnetosphere. Image Credit: NASA.

As scientists try to better understand the space weather system around Earth, they rely on multipoint observations such as this to connect what's seen on the ground to what's seen in space. In this case THEMIS data connected to GPS data, but such combinations are increasingly being used to watch how Earth is affected by its closest star. Eventually such observations could lead to improvements in space weather predictions, which would be as useful for spacecraft operators as terrestrial weather forecasts are for us here on Earth.

For more information about NASA’s THEMIS mission, visit: http://www.nasa.gov/themis

Images (mentioned), Text, Credits: NASA's Goddard Space Flight Center / Karen C. Fox.

Greetings, Orbiter.ch

Mystery of Planet-forming Disks Explained by Magnetism












NASA - Spitzer Space Telescope patch.

March 6, 2014


Image above: Magnetic loops carry gas and dust above disks of planet-forming material circling stars, as shown in this artist's conception. Image Credit: NASA/JPL-Caltech.

Astronomers say that magnetic storms in the gas orbiting young stars may explain a mystery that has persisted since before 2006.

Researchers using NASA's Spitzer Space Telescope to study developing stars have had a hard time figuring out why the stars give off more infrared light than expected. The planet-forming disks that circle the young stars are heated by starlight and glow with infrared light, but Spitzer detected additional infrared light coming from an unknown source.

A new theory, based on three-dimensional models of planet-forming disks, suggests the answer: Gas and dust suspended above the disks on gigantic magnetic loops like those seen on the sun absorb the starlight and glow with infrared light.

"If you could somehow stand on one of these planet-forming disks and look at the star in the center through the disk atmosphere, you would see what looks like a sunset," said Neal Turner of NASA's Jet Propulsion Laboratory, Pasadena, Calif.

The new models better describe how planet-forming material around stars is stirred up, making its way into future planets, asteroids and comets.

While the idea of magnetic atmospheres on planet-forming disks is not new, this is the first time they have been linked to the mystery of the observed excess infrared light.  According to Turner and colleagues, the magnetic atmospheres are similar to what takes place on the surface of our sun, where moving magnetic field lines spur tremendous solar prominences to flare up in big loops.

Stars are born out of collapsing pockets in enormous clouds of gas and dust, rotating as they shrink down under the pull of gravity. As a star grows in size, more material rains down toward it from the cloud, and the rotation flattens this material out into a turbulent disk. Ultimately, planets clump together out of the disk material.

Spitzer Space Telescope. Image Credits: NASA/JPL-Caltech

In the 1980s, the Infrared Astronomical Satellite mission, a joint project that included NASA, began finding more infrared light than expected around young stars.  Using data from other telescopes, astronomers pieced together the presence of dusty disks of planet-forming material.  But eventually it became clear the disks alone weren't enough to account for the extra infrared light -- especially in the case of stars a few times the mass of the sun.

One theory introduced the idea that instead of a disk, the stars were surrounded by a giant dusty halo, which intercepted the star's visible light and re-radiated it at infrared wavelengths. Then, recent observations from ground-based telescopes suggested that both a disk and a halo were needed. Finally, three-dimensional computer modeling of the turbulence in the disks showed the disks ought to have fuzzy surfaces, with layers of low-density gas supported by magnetic fields, similar to the way solar prominences are supported by the sun's magnetic field.

The new work brings these pieces together by calculating how the starlight falls across the disk and its fuzzy atmosphere. The result is that the atmosphere absorbs and re-radiates enough to account for all the extra infrared light.

"The starlight-intercepting material lies not in a halo, and not in a traditional disk either, but in a disk atmosphere supported by magnetic fields," said Turner. "Such magnetized atmospheres were predicted to form as the disk drives gas inward to crash onto the growing star."

Over the next few years, astronomers will further test these ideas about the structure of the disk atmospheres by using giant ground-based telescopes linked together as interferometers.  An interferometer combines and processes data from multiple telescopes to show details finer than each telescope can see alone. Spectra of the turbulent gas in the disks will also come from NASA's SOFIA telescope, the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile, and from NASA's James Webb Space Telescope after its launch in 2018.

JPL manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colo. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA. For more information about Spitzer, visit http://spitzer.caltech.edu and http://www.nasa.gov/spitzer

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

Cheers, Orbiter.ch

Martian Sand Dunes in Spring












NASA - Mars Reconnaissance Orbiter (MRO) logo.

6 March 2014


Mars’ northern-most sand dunes are beginning to emerge from their winter cover of seasonal carbon dioxide (dry) ice. Dark, bare south-facing slopes are soaking up the warmth of the sun.

The steep lee sides of the dunes are also ice-free along the crest, allowing sand to slide down the dune. Dark splotches are places where ice cracked earlier in spring, releasing sand. Soon the dunes will be completely bare and all signs of spring activity will be gone.

Mars Reconnaissance Orbiter (MRO) spacecraft

This image was acquired by the HiRISE camera aboard NASA's Mars Reconnaissance Orbiter on Jan. 16, 2014. The University of Arizona, Tucson, operates the HiRISE camera, which was built by Ball Aerospace & Technologies Corp., Boulder, Colo. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter Project for the NASA Science Mission Directorate, Washington.

More information and image products: http://www.uahirise.org/ESP_035033_2635

For more information about Mars Reconnaissance Orbiter (MRO), visit: http://www.nasa.gov/mission_pages/MRO/main/

Images, Text, Credits: NASA/JPL-Caltech/Univ. of Arizona / Caption: Candy Hansen.

Cheers, Orbiter.ch

Hubble witnesses an asteroid mysteriously disintegrating












ESA - Hubble Space Telescope logo.

6 March 2014

Asteroid P/2013 R3 breaks apart

The NASA/ESA Hubble Space Telescope has photographed the never-before-seen break-up of an asteroid, which has fragmented into as many as ten smaller pieces. Although fragile comet nuclei have been seen to fall apart as they approach the Sun, nothing like the breakup of this asteroid, P/2013 R3, has ever been observed before in the asteroid belt.

"This is a rock. Seeing it fall apart before our eyes is pretty amazing," said David Jewitt of UCLA, USA, who led the astronomical forensics investigation.

Asteroid P/2013 R3 breaks apart (labelled)

The crumbling asteroid, designated P/2013 R3, was first noticed as an unusual, fuzzy-looking object on 15 September 2013 by the Catalina and Pan-STARRS sky surveys. Follow-up observations on 1 October with the Keck Telescope on Mauna Kea, Hawaii, revealed three co-moving bodies embedded in a dusty envelope that is nearly the diameter of Earth.

"Keck showed us that this thing was worth looking at with Hubble,” Jewitt said. With its superior resolution, the space-based Hubble observations soon showed that there were really ten distinct objects, each with comet-like dust tails. The four largest rocky fragments are up to 200 metres in radius, about twice the length of a football pitch.

Disintegrating asteroid P/2013 R3 as viewed by Hubble on 29 October 2013

The Hubble data showed that the fragments are drifting away from each other at a leisurely 1.5 kilometres per hour — slower than the speed of a strolling human. The asteroid began coming apart early last year, but the latest images show that pieces continue to emerge.

"This is a really bizarre thing to observe — we've never seen anything like it before,” says co-author Jessica Agarwal of the Max Planck Institute for Solar System Research, Germany. "The break-up could have many different causes, but the Hubble observations are detailed enough that we can actually pinpoint the process responsible.”

Disintegrating asteroid P/2013 R3 as viewed by Hubble on 15 November 2013

The ongoing discovery of more fragments makes it unlikely that the asteroid is disintegrating due to a collision with another asteroid, which would be instantaneous and violent in comparison to what has been observed. Some of the debris from such a high-velocity smash-up would also be expected to travel much faster than has been observed.

It is also unlikely that the asteroid is breaking apart due to the pressure of interior ices warming and vaporising. The object is too cold for ices to significantly sublimate, and it has presumably maintained its nearly 480-million-kilometre distance from the Sun for much of the age of the Solar System.

Disintegrating asteroid P/2013 R3 as viewed by Hubble on 13 December

This leaves a scenario in which the asteroid is disintegrating due to a subtle effect of sunlight that causes the rotation rate to slowly increase over time. Eventually, its component pieces gently pull apart due to centrifugal force. The possibility of disruption by this phenomenon — known as the YORP effect [1] — has been discussed by scientists for several years but, so far, never reliably observed (eso1405).

For break-up to occur, P/2013 R3 must have a weak, fractured interior, probably the result of numerous ancient and non-destructive collisions with other asteroids. Most small asteroids are thought to have been severely damaged in this way, giving them a "rubble pile” internal structure. P/2013 R3 itself is probably the product of collisional shattering of a bigger body some time in the last billion years.

Disintegrating asteroid P/2013 R3 as viewed by Hubble on 14 January 2014

"This is the latest in a line of weird asteroid discoveries, including the active asteroid P/2013 P5, which we found to be spouting six tails,” says Agarwal. "This indicates that the Sun may play a large role in disintegrating these small Solar System bodies, by putting pressure on them via sunlight.”

Artist's illustration of disintegrating asteroid P/2013 R3

P/2013 R3's remnant debris, weighing in at 200 000 tonnes, will provide a rich source of meteoroids in the future. Most will eventually plunge into the Sun, but a small fraction of the debris may one day blaze across our sky as meteors.

video
The breakup of asteroid P/2013 R3

Notes:

[1] In full, this effect is known as the Yarkovsky–O'Keefe–Radzievskii–Paddack effect. This effect occurs when light from the Sun is absorbed by a body and then re-emitted as heat. When the shape of the emitting body is not perfectly regular, more heat is emitted from some regions than others. This creates a small imbalance that causes a small but constant torque on the body, which changes its spin rate.

Notes for editors:

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

[1] The results will be published in a paper entitled "Disintegrating Asteroid P/2013 R3”, to appear in the Astrophysical Journal Letters on 6 March 2014.

[2] The international team of astronomers in this study consists of D. Jewitt (UCLA, USA), J. Agarwal (MPS, Germany), J. Li (UCLA, USA), H. Weaver (Johns Hopkins University, USA), M. Mutchler (STScI, USA), and S. Larson (University of Arizona, USA).

Links:

Science paper: http://www.spacetelescope.org/static/archives/releases/science_papers/heic1405a.pdf

NASA Hubble website: http://hubblesite.org/

Images, Video, Text, Credits: NASA, ESA, and D. Jewitt (UCLA) and A. Feild (STScI).

Best regards, Orbiter.ch

Crashing Comets Explain Surprise Gas Clump Around Young Star












ESO - ALMA logo.

6 March 2014

ALMA reveals an enigmatic gas clump in debris disc around Beta Pictoris

Artist's impression of Beta Pictoris

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in northern Chile have today announced the discovery of an unexpected clump of carbon monoxide gas in the dusty disc around the star Beta Pictoris. This is a surprise, as such gas is expected to be rapidly destroyed by starlight. Something — probably frequent collisions between small, icy objects such as comets — must be causing the gas to be continuously replenished. The new results are published today in the journal Science.

Beta Pictoris, a nearby star easily visible to the naked eye in the southern sky, is already hailed as the archetypal young planetary system. It is known to harbour a planet that orbits some 1.2 billion kilometres from the star, and it was one of the first stars found to be surrounded by a large disc of dusty debris [1].

Map of the sky around Beta Pictoris

New observations from ALMA now show that the disc is permeated by carbon monoxide gas. Paradoxically the presence of carbon monoxide, which is so harmful to humans on Earth, could indicate that the Beta Pictoris planetary system may eventually become a good habitat for life. The cometary bombardment that its planets are currently undergoing is likely providing them with life-enabling water [2].

But carbon monoxide is easily and rapidly broken up by starlight — it can only last about 100 years where it is observed in the Beta Pictoris disc. Seeing it in the 20-million year old Beta Pictoris disc is a complete surprise. So where did it come from, and why is it still there?

Around Beta Pictoris

“Unless we are observing Beta Pictoris at a very unusual time, the carbon monoxide must be continuously replenished,” said Bill Dent, an ESO astronomer at the Joint ALMA Office in Santiago, Chile, and lead author on a paper published today in the journal Science. “The most abundant source of carbon monoxide in a young solar system is collisions between icy bodies, from comets up to larger planet-sized objects.”

But the rate of destruction must be very high: “To get the amount of carbon monoxide we observe, the rate of collisions would be truly startling — one large comet collision every five minutes,” noted Aki Roberge, an astronomer at NASA’s Goddard Research Center in Greenbelt, USA, and coauthor of the paper. “To get this number of collisions, this would have to be a very tight, massive comet swarm.”

But there was another surprise in the ALMA observations, which did not just discover the carbon monoxide, but also mapped its location in the disc, through ALMA’s unique ability to simultaneously measure both position and velocity: the gas is concentrated in a single compact clump. This concentration lies 13 billion kilometres from the star, which is about three times the distance of Neptune from the Sun. Why the gas is in this small clump so far from the star is a mystery.

“This clump is an important clue to what is going on in the outer reaches of this young planetary system,” says Mark Wyatt, an astronomer at the University of Cambridge, UK, and a co-author on the paper. He goes on to explain that there are two ways such a clump can form: “Either the gravitational pull of an as yet unseen planet similar in mass to Saturn is concentrating the cometary collisions into a small area, or what we are seeing are the remnants of a single catastrophic collision between two icy Mars-mass planets”.

ALMA image of carbon monoxide around Beta Pictoris (infographic)

Both of these possibilities give astronomers reason to be optimistic that there are several more planets waiting to be found around Beta Pictoris. “Carbon monoxide is just the beginning — there may be other more complex pre-organic molecules released from these icy bodies,” adds Roberge.

video
Colliding Comets Hint at Unseen Exoplanet

Further observations are planned with ALMA, which is still ramping up to its full capabilities, to shed more light on this intriguing planetary system, and so help us to understand what conditions were like during the formation of the Solar System.

Notes:

[1] Many stars are surrounded by swirling clouds of dust, known as debris discs.They are the remains of a collisional cascade of the rocks in orbit around the star, much like the collisional breakup of the space station depicted in the movie Gravity (but on a much larger scale). Earlier observations of Beta Pictoris were reported in eso1024 and eso0842.

[2] Comets contain ices of carbon monoxide, carbon dioxide, ammonia and methane, but the majority component is a mixture of dust and water ice.

More information:

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Southern Observatory (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

This research was presented in a paper entitled “Molecular Gas Clumps from the Destruction of Icy Bodies in the β Pictoris Debris Disk” to appear in the journal Science on 6 March 2014.

The team is composed of W.R.F. Dent (Joint ALMA Office, Santiago, Chile [JAO]), M.C. Wyatt (Institute of Astronomy, Cambridge, UK [IoA]), A. Roberge (NASA Goddard Space Flight Center, Greenbank, USA), J.-C. Augereau (Institut de Planétologie et d'Astrophysique de Grenoble, France [IPAG]), S. Casassus (Universidad de Chile, Santiago, Chile), S. Corder (JAO), J.S. Greaves (University of St. Andrews, UK), I. de Gregorio-Monsalvo (JAO), A. Hales (JAO), A.P.Jackson (IoA), A. Meredith Hughes (Wesleyan University, Middletown, USA), A.-M. Lagrange (IPAG), B. Matthews (National Research Council of Canada, Victoria, Canada) and D. Wilner (Smithsonian Astrophysical Observatory, Cambridge, USA).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning the 39-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Links:

Science paper: http://www.sciencemag.org/lookup/doi/10.1126/science.1248726

NRAO release: https://public.nrao.edu/alma-sees-icy-wreckage

NASA release: http://www.nasa.gov/content/goddard/nearby-stars-icy-debris-suggests-shepherd-planet/

ALMA pictures: http://www.eso.org/public/images/archive/category/alma/

Further information about ALMA: http://www.eso.org/public/teles-instr/alma/

Image, Video, Text, Credits: ESO / NASA's Goddard Space Flight Center/ F. Reddy / IAU and Sky & Telescope / Digitized Sky Survey 2 / ALMA (ESO/NAOJ/NRAO) and NASA's Goddard Space Flight Center/F. Reddy.

Greetings, Orbiter.ch

Lava floods the ancient plains of Mars












ESA - Mars Express Mission patch.

6 March 2014

Lava flows in Daedalia Planum

Two distinct volcanic eruptions have flooded this area of Daedalia Planum with lava, flowing around an elevated fragment of ancient terrain.

The images were acquired by ESA’s Mars Express on 28 November 2013 towards the eastern boundary of the gigantic Tharsis Montes volcanic region, where the largest volcanoes on Mars are found.

The lava flows seen in this image come from Arsia Mons, the southernmost volcano in the Tharsis complex, which lies around 1000 km to the northwest of the region featured here.

Daedalia Planum and Mistretta Crater in context

This volcanic region is thought to have been active until tens of millions of years ago, relatively recent on the planet’s geological timescale that spans 4.6 billion years.

The rough elevated terrain at the bottom of the main image is imprinted with three distinct but eroded impact craters, the largest of which is about 16.5 km wide and named Mistretta. The ancient foundation it sits on once belonged to the vast southern highlands, but is now surrounded by a sea of lava, like many other isolated fragments that can be seen in the wider context image.

Daedalia Planum lava flows close up

Lava flows from two distinct eruptions have reached the foot of this particular feature.

The first eruption produced the lava flow to the south of the island (to the left in the main image and to the right in the close-up perspective image). This flow subsequently experienced extensive faulting due to tectonic forces, resulting in the numerous trough systems.

The younger lava flow (right in the main image, left in the close-up image) must have taken place after the tectonic event that caused the faulting because it overlies both the older lava surface and the tectonic features. Indeed, at the front of the flow, several tongues of lava have flowed preferentially along the lower ground of the troughs.

Topography of Daedalia Planum and Mistretta Crater

Another clear indication of the relative ages of the two flows is given by the impact craters: the older, fractured lava flow has more and larger ones than the younger flow.

The younger lava flow also has a rough texture, with many small ridges on the surface. These features form as result of speed gradients within the lava flow due to the difference in temperature between the hot, faster-flowing interior lava and the cooler, slower ‘roof’ of the flow that is exposed to the atmosphere.

But neither lava flow travelled unimpeded. The highland ‘island’ in this scene created an obstacle, forcing them to circle its flanks and override its base, most noticeable to the north (to the right in the main colour, topography, and 3D images).

Daedalia Planum and Mistretta Crater in 3D

The wider Daedalia Planum region bears witness to numerous lava flows similar to these, each one overlaying the last. By carefully studying the boundaries between overlapping flows, planetary scientists can build up a picture of the eruption history of the Red Planet’s giant volcanoes.

Related links:

High Resolution Stereo Camera: http://berlinadmin.dlr.de/Missions/express/indexeng.shtml

Behind the lens: http://www.esa.int/Our_Activities/Space_Science/Mars_Express/Behind_the_lens

Frequently asked questions: http://www.esa.int/Our_Activities/Space_Science/Mars_Express/Frequently_asked_questions

ESA Planetary Science archive (PSA): http://www.rssd.esa.int/PSA

NASA Planetary Data System: http://pds-geosciences.wustl.edu/missions/mars_express/hrsc.htm

HRSC data viewer: http://hrscview.fu-berlin.de/

More about:

Mars Express overview: http://www.esa.int/Our_Activities/Space_Science/Mars_Express_overview

Mars Express 10 year brochure: http://esamultimedia.esa.int/multimedia/publications/BR-312/

Mars Express in depth: http://sci.esa.int/science-e/www/area/index.cfm?fareaid=9

Mars Express top 10 discoveries: http://sci.esa.int/jump.cfm?oid=51820

Images, Text, Credits: ESA / DLR / FU Berlin / NASA / MGS MOLA Science Team.

Greetings, Orbiter.ch

mercredi 5 mars 2014

Russian scientists will construct equipment for ESA JUICE probe










Moscow Institute of Physics and Technology logo.

March 5, 2014

Russian scientists will construct equipment for a European Space Agency probe to Jupiter (JUICE), the Moscow Institute of Physics and Technology said Wednesday.

Along with observing the solar system’s largest planet, the Jupiter Icy Moon Explorer is to visit three of the four Jovian moons discovered by Galileo: Callisto, Ganymede and Europa.

Artist's view of the JUICE spacecraft exploring the Jovian system

The spacecraft is planned to carry 11 scientific instruments, one of which will include a radiation detector built by Russia.

The detector would be the first Russian device to visit the outer solar system and will help scientists characterize wind patterns on Jupiter as well as analyze gases escaping from Europa.

According to the institute, the head of the Russian effort, Alexander Rodin, said that German scientists approached their Russian counterparts to develop equipment necessary to detect and analyze tetrahertz-band radiation.

Such a detector would be sensitive enough to observe volatile compounds as they leak out of cracks in the ice covering Europa, possibly revealing details about the water oceans that most planetary scientists believe exist beneath the moon’s surface.

Artist's view of JUICE approaching Europa

In January, the head of the ESA told reporters that further cooperation with Russia could follow last year’s agreement to jointly develop the ExoMars mission to search for signs of life on the Red Planet.

The mission would be the third in the history of spaceflight to orbit the solar system’s largest planet and is scheduled for launch in 2022. It will arrive at the gas giant after a voyage of eight years.

JUICE will end up in orbit around Ganymede, where it will study the moon's icy surface and internal structure, including its subsurface ocean.

JUICE mission scheduled at Ganymede description

The largest moon in the Solar System, Ganymede is the only one known to generate its own magnetic field, and JUICE will observe the unique magnetic and plasma interactions with Jupiter's magnetosphere in detail.

"Jupiter and its icy moons constitute a kind of mini-Solar System in their own right, offering European scientists and our international partners the chance to learn more about the formation of potentially habitable worlds around other stars," says Dmitrij Titov, ESA's JUICE Study Scientist.

For more information about ESA JUICE Mission, visit: http://sci.esa.int/juice/

Images, Text, Credits: ESA / AOES / C. Caroll / ROSCOSMOS / RIA Novosti / Catherine Laplace-Builhe.

Cheers, Orbiter.ch

Warm Rivers Play Role in Arctic Sea Ice Melt















NASA - EOS Terra Mission patch.

March 5, 2014

Before and After Images:


Images above: Beaufort Sea surface temperatures where Canada's Mackenzie River discharges into the Arctic Ocean, measured by NASA's MODIS instrument. The left image is from June 14, 2012. In the right image (July 5, 2012), warm river waters had broken through a shoreline sea ice barrier to enhance sea ice melt. Image Credit: NASA.

The heat from warm river waters draining into the Arctic Ocean is contributing to the melting of Arctic sea ice each summer, a new NASA study finds.

A research team led by Son Nghiem of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., used satellite data to measure the surface temperature of the waters discharging from a Canadian river into the icy Beaufort Sea during the summer of 2012. They observed a sudden influx of warm river waters into the sea that rapidly warmed the surface layers of the ocean, enhancing the melting of sea ice. A paper describing the study is now published online in the journal Geophysical Research Letters.

This Arctic process contrasts starkly with those that occur in Antarctica, a frozen continent without any large rivers. The sea ice cover in the Southern Ocean surrounding Antarctica has been relatively stable, while Arctic sea ice has been declining rapidly over the past decade.

“River discharge is a key factor contributing to the high sensitivity of Arctic sea ice to climate change,” said Nghiem. “We found that rivers are effective conveyers of heat across immense watersheds in the Northern Hemisphere. These watersheds undergo continental warming in summertime, unleashing an enormous amount of energy into the Arctic Ocean, and enhancing sea ice melt. You don’t have this in Antarctica.”

The team said the impacts of these warm river waters are increasing due to three factors. First, the overall volume of water discharged from rivers into the Arctic Ocean has increased. Second, rivers are getting warmer as their watersheds (drainage basins) heat up. And third, Arctic sea ice cover is becoming thinner and more fragmented, making it more vulnerable to rapid melt. In addition, as river heating contributes to earlier and greater loss of the Arctic’s reflective sea ice cover in summer, the amount of solar heat absorbed into the ocean increases, causing even more sea ice to melt.

To demonstrate the extensive intrusion of warm Arctic river waters onto the Arctic sea surface, the team selected the Mackenzie River in western Canada. They chose the summer of 2012 because that year holds the record for the smallest total extent of sea ice measured across the Arctic in the more than 30 years that satellites have been making observations.

The researchers used data from satellite microwave sensors to examine the extent of sea ice in the study area from 1979 to 2012 and compared it to reports of Mackenzie River discharge. “Within this period, we found the record largest extent of open water in the Beaufort Sea occurred in 1998, which corresponds to the year of record high discharge from the river,” noted co-author Ignatius Rigor of the University of Washington in Seattle.

The team analyzed data from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on NASA’s Terra satellite to examine sea ice patterns and sea surface temperatures in the Beaufort Sea. They observed that on June 14, 2012, a stretch of landfast sea ice (sea ice that is stuck to the coastline) formed a barrier that held the river discharge close to its delta. After the river water broke through the ice barrier, sometime between June 14 and July 5, the team saw that the average surface temperature of the area of open water increased by 11.7 degrees Fahrenheit (6.5 degrees Celsius).

video

Animation above: NASA MODIS movie from June 14, 2012, shows a blue band of sea ice stuck to the Mackenzie River shoreline. The map fades, revealing the seafloor depth below. The band of stuck sea ice closely follows the highlighted 25-meter-depth contour line. The seafloor topography helps delay river discharge. Image Credit: NASA/International Bathymetric Chart of the Arctic Ocean.

“When the Mackenzie River’s water is held back behind the sea ice barrier, it accumulates and gets warmer later in the summer,” said Nghiem. “So when it breaks through the barrier, it’s like a strong surge, unleashing warmer waters into the Arctic Ocean that are very effective at melting sea ice. Without this ice barrier, the warm river waters would trickle out little by little, and there would be more time for the heat to dissipate to the atmosphere and to the cooler, deeper ocean.”

“If you have an ice cube and drop a few water droplets on it, you’re not going to see rapid melt,” said co-author Dorothy Hall of NASA’s Goddard Space Flight Center in Greenbelt, Md. “But if you pour a pitcher of warm water on the ice cube, it will appear to get smaller before your eyes. When warm river water surges onto sea ice, the ice melts rapidly.”

Nghiem’s team has linked this sea ice barrier, which forms recurrently and persistently in this area, to the physical characteristics of the shallow ocean continental shelf, and concludes the seafloor plays a role in delaying river discharge by holding the barrier in place along the shore of the Mackenzie delta.

The team estimated the heating power carried by the discharge of the 72 rivers in North America, Europe and Asia that flow into the Arctic Ocean. Based on published research of their average annual river discharge, and assuming an average summer river water temperature of around 41 degrees Fahrenheit (5 degrees Celsius), they calculated that the rivers are carrying as much heat into the Arctic Ocean each year as all of the electric energy used by the state of California in 50 years at today’s consumption rate.

While MODIS can accurately measure sea surface temperature where rivers discharge warm waters into the Arctic Ocean, researchers currently lack reliable field measurements of subsurface temperatures across the mouths of river channels. Nghiem said more studies are needed to establish water temperature readings in Arctic-draining rivers to further understand their contribution to sea ice melt.

NASA monitors Earth’s vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth’s interconnected natural systems with long-term data records and computer analysis tools to better understand how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

For more information about NASA’s Earth science activities in 2014, visit: http://www.nasa.gov/earthrightnow .

For information on the latest NASA Earth science findings, visit: http://www.nasa.gov/earth .

Images (mentioned), Animation / Text, Credits: NASA / JPL / Alan Buis / Written by Maria-Jose Vinas, NASA Earth Science News Team.

Greetings, Orbiter.ch