jeudi 21 septembre 2017

Spacewalk VR Training, Muscle and Bone Research Today

ISS - Expedition 53 Mission patch.

September 21, 2017

International Space Station (ISS). Image Credit: NASA

The Expedition 53 crew is getting ready for a trio of spacewalks next month while helping scientists understand what living in space does to the human body.

NASA astronauts Randy Bresnik and Mark Vande Hei trained for a spacewalk emergency today wearing virtual reality gear. The spacewalkers practiced maneuvering specialized jet packs attached to their spacesuits in the unlikely event they become untethered from the station.

Image above: NASA astronaut Joe Acaba is seen during a spacewalk in March 2009. He was working on the Starboard-1 truss structure while space shuttle Discovery was docked to the station during STS-119. Image Credit: NASA.

The duo will go on a pair of spacewalks on Oct. 5 and 10. NASA astronaut Joe Acaba will join Bresnik Oct. 18 for the third and final spacewalk. The three spacewalkers will replace and lubricate one of two end effectors on the tip of the Canadarm2 robotic arm. They will also replace a pair of cameras located on the station’s truss structure.

More muscle and bone research continued today as cosmonaut Sergey Ryazanskiy joined Italian astronaut Paolo Nespoli for the Sarcolab-3 study. The research observes leg muscle and tendon changes caused by microgravity using an ultrasound scan and other sensors during an exercise session. Bresnik collected his breath sample to help document any bone marrow and blood cell changes his body may be experiencing in space.

Related links:


Bone marrow:

Expedition 53:

Space Station Research and Technology:

International Space Station (ISS):

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

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Thar be rovers

ESA - Mars Express Mission patch.

Sept. 21, 2017

(Click on the image for enlarge)

In the week of 18 September 2017, the low-resolution webcam on ESA’s Mars Express captured some impressive images from between 3000 km to 5000 km altitude.

The image series is being used to calibrate the camera now that it has been promoted to a ‘full’ science instrument (Mars webcam goes pro).

This week, the images provided reasonably good definition for many craters on the surface, including several that are occupied by NASA rovers.

In the composite image above, moving from lower left to upper right, three craters are circled.

The first shows Gale crater, which is occupied by NASA’s Curiosity rover. The second circle, to the right in the middle, shows Gusev Crater, home of the retired Spirit rover. The last circle, at top right of the middle image, also indicates the location of Gale crater and Curiosity.

ESA’s Mars Express

In addition to studies into Mars’ atmosphere, clouds, dust and atmospheric structures and for tracking variations in the polar ice cap, all of the webcam images are published in a public gallery in Flickr, and are automatically posted via Twitter, sometimes within a couple hours of acquisition at Mars.

Mars webcam goes pro:

Mars Express:

Mars Webcam:

Images, Text, Credits: ESA/CC BY-SA 3.0 IGO.


mercredi 20 septembre 2017

Two Stars, Three Dimensions, and Oodles of Energy

NASA - Chandra X-ray Observatory patch.

Sept. 20, 2017

For decades, astronomers have known about irregular outbursts from the double star system V745 Sco, which is located about 25,000 light years from Earth. Astronomers were caught by surprise when previous outbursts from this system were seen in 1937 and 1989. When the system erupted on February 6, 2014, however, scientists were ready to observe the event with a suite of telescopes including NASA’s Chandra X-ray Observatory.

V745 Sco is a binary star system that consists of a red giant star and a white dwarf locked together by gravity. These two stellar objects orbit so closely around one another that the outer layers of the red giant are pulled away by the intense gravitational force of the white dwarf.  This material gradually falls onto the surface of the white dwarf. Over time, enough material may accumulate on the white dwarf to trigger a colossal thermonuclear explosion, causing a dramatic brightening of the binary called a nova. Astronomers saw V745 Sco fade by a factor of a thousand in optical light over the course of about 9 days.

Astronomers observed V745 Sco with Chandra a little over two weeks after the 2014 outburst. Their key finding was it appeared that most of the material ejected by the explosion was moving towards us. To explain this, a team of scientists from the INAF-Osservatorio Astronomico di Palermo, the University of Palermo, and the Harvard-Smithsonian Center for Astrophysics constructed a three-dimensional (3D) computer model of the explosion, and adjusted the model until it explained the observations. In this model they included a large disk of cool gas around the equator of the binary caused by the white dwarf pulling on a wind of gas streaming away from the red giant.

The computer calculations showed that the nova explosion’s blast wave and ejected material were likely concentrated along the north and south poles of the binary system. This shape was caused by the blast wave slamming into the disk of cool gas around the binary. This interaction caused the blast wave and ejected material to slow down along the direction of this disk and produce an expanding ring of hot, X-ray emitting gas. X-rays from the material moving away from us were mostly absorbed and blocked by the material moving towards Earth, explaining why it appeared that most of the material was moving towards us.

In the figure showing the new 3D model of the explosion, the blast wave is yellow, the mass ejected by the explosion is purple, and the disk of cooler material, which is mostly untouched by the effects of the blast wave, is blue. The cavity visible on the left side of the ejected material (see the labeled version) is the result of the debris from the white dwarf’s surface being slowed down as it strikes the red giant. An inset shows an optical image from the Siding Springs Observatory in Australia with V745 Sco in the center.

Chandra X-Ray Observatory. Animation Credits: NASA/CXC

An extraordinary amount of energy was released during the explosion, equivalent to about 10 million trillion hydrogen bombs. The authors estimate that material weighing about one tenth of the Earth’s mass was ejected.

While this stellar-sized belch was impressive, the amount of mass ejected was still far smaller than the amount what scientists calculate is needed to trigger the explosion. This means that despite the recurrent explosions, a substantial amount of material is accumulating on the surface of the white dwarf. If enough material accumulates, the white dwarf could undergo a thermonuclear explosion and be completely destroyed. Astronomers use these so-called Type Ia supernovas as cosmic distance markers to measure the expansion of the Universe.

The scientists were also able to determine the chemical composition of the material expelled by the nova. Their analysis of this data implies that the white dwarf is mainly composed of carbon and oxygen.

A paper describing these results was published in the February 1st, 2017 issue of the Monthly Notices of the Royal Astronomical Society and is available online. The authors are Salvatore Orlando from the INAF-Osservatorio Astronomico di Palermo in Italy, Jeremy Drake from the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA and Marco Miceli from the University of Palermo.

NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.

Read More from NASA's Chandra X-ray Observatory:

Royal Astronomical Society paper:

For more Chandra images, multimedia and related materials, visit:

Chandra X-Ray Observatory:

Image Credits: Illustrated model: NASA/CXC/M.Weiss/Animation (mentioned), Text, Credits: NASA/Lee Mohon.

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End-of-Summer Arctic Sea Ice Extent Is Eighth Lowest on Record

NASA logo / National Snow and Ice Data Center (NSIDC) logo.

Sept. 20, 2017

Arctic sea ice appeared to have reached its yearly lowest extent on Sept. 13, NASA and the NASA-supported National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder have reported. Analysis of satellite data by NSIDC and NASA showed that at 1.79 million square miles (4.64 million square kilometers), this year’s Arctic sea ice minimum extent is the eighth lowest in the consistent long-term satellite record, which began in 1978.

Arctic Sea Ice from March to September 2017

Video above: Arctic sea ice appears to have reached a record low wintertime maximum extent for 2017, according to scientists at the NASA-supported National Snow and Ice Data Center (NSIDC) in Boulder, Colorado. Observations indicate that on Sept. 13, 2017 ice extent shrunk to the eighth lowest in the satellite record, at 4.64 million square kilometers, or 1.79 million square miles. Video Credits: NASA's Scientific Visualization Studio/Helen-Nicole Kostis.

Arctic sea ice, the layer of frozen seawater covering much of the Arctic Ocean and neighboring seas, is often referred to as the planet’s air conditioner: its white surface bounces solar energy back to space, cooling the globe. The sea ice cap changes with the season, growing in the autumn and winter and shrinking in the spring and summer. Its minimum summertime extent, which typically occurs in September, has been decreasing, overall, at a rapid pace since the late 1970s due to warming temperatures.

This year, temperatures in the Arctic have been relatively moderate for such high latitudes, even cooler than average in some regions. Still, the 2017 minimum sea ice extent is 610,000 square miles (1.58 million square kilometers) below the 1981-2010 average minimum extent.

“How much ice is left at the end of summer in any given year depends on both the state of the ice cover earlier in the year and the weather conditions affecting the ice,” said Claire Parkinson, senior climate scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The weather conditions have not been particularly noteworthy this summer. The fact that we still ended up with low sea ice extents is because the baseline ice conditions today are worse than the baseline 38 years ago.”

Image above: A still image of the Arctic sea ice on Sept. 13, 2017, when the ice reached its annual minimum. In addition, a yellow line marks the 30-year  average minimum sea ice extent computed over the time period from 1981  through 2010. Image Credit: NASA's Scientific Visualization Studio/Helen-Nicole Kostis.

The three years with the lowest Arctic ice extents on record — 2012, 2016 and 2007 — experienced unusual weather conditions, including strong summer storms that hammered the ice cover and sped up its melt. “In all of those cases, the weather conditions contributed to the reduced ice coverage. But if the exact same weather system had occurred three decades ago, it is very unlikely that it would have caused as much damage to the sea ice cover, because back then the ice was thicker and it more completely covered the region, hence making it more able to withstand storms,” Parkinson said.

On the other side of the planet, Antarctica is heading to its maximum yearly sea ice extent, which typically occurs in September or early October. This year’s maximum extent is likely to be among the five lowest in the satellite record — a continuation of the low extents in 2015 and 2016 that represented a dramatic turn of events after a streak of record high maximum extents in 2012, 2013 and 2014. So far, the September Antarctic ice extents this year are comparable to those of a year ago.

“What had been most surprising about the changing sea ice coverage in the past three decades was the fact that the Antarctic sea ice was increasing instead of decreasing,” Parkinson said. “The fact of Arctic sea ice decreases was not as shocking because this was expected with a warming climate, although the overall rate of the decreases was greater than most models had forecast.”

Parkinson said that although it is still too early to talk about a long-term reversal in the behavior of Antarctic sea ice, the decreases witnessed in the past two years provide important data to test the various hypotheses that scientists have put forward to explain why Antarctic sea ice coverage had been increasing, overall, between 1979 and 2015.

Adding the Antarctic and Arctic sea ice extents month by month through the satellite record shows that globally the Earth has been losing sea ice since the late 1970s in each portion of the annual cycle of ice growth and decay. “In fact, this year, every single month from January through August experienced a new monthly record low in global sea ice extents,” Parkinson said.

Related Link:

National Snow and Ice Data Center (NSIDC):

Image (mentioned), Video (mentioned), Text, Credits: NASA/Sara Blumberg/Earth Science News Team, by Maria-José Viñas.


Detectors: unique superconducting magnets

CERN - European Organization for Nuclear Research logo.

20 Sep 2017

Image above: The enormous toroidal superconducting magnet of ATLAS during its installation. Each of its eight coils, the last of which is being assembled in this photo, is 25 metres long. (Image: ATLAS/CERN).

Even before they were used widely in particle accelerators, superconducting magnets were adopted for the detectors used to analyse collisions. A magnetic field is essential for identifying the particles emerging from collisions: it curves their trajectory allowing physicists to calculate their momentum and to establish whether they have a positive or negative charge. The stronger the field and the larger the volume on which it acts, the higher the resolution of the detector.

As early as the 1960s, physicists saw the potential benefits of using superconducting magnets in their detectors. In the early 1970s, experiments in the United States and at CERN were developing large superconducting magnets capable of generating fields of up to 3.5 Tesla. This development work was all the more daring since the technology was still in its infancy. But contrary to the magnets for accelerators, which need to be produced in their dozens, the magnets in detectors are unique.

One of the trailblazers of these detectors was CERN’s Big European Bubble Chamber (BEBC), which entered service in 1973 and in which the superconducting magnet generated a field of 3.5 Tesla. Its stored energy was almost 800 megajoules, a level of performance that wouldn’t be bettered until the late 1990s.

Image above: The superconducting coil of CMS, the biggest superconducting solenoid magnet ever built, being inserted in its cryostat. (Image: Maximilien Brice/CERN).

In the 1980s, significant progress was made on improving the magnets’ performance and making them more “transparent”, so that they didn’t interact with the particles and change their characteristics. Increasingly larger magnets were constructed and the work culminated in the 2000s with the giant superconducting magnets of the landmark CMS and ATLAS experiments at the Large Hadron Collider (LHC). The first of these is a huge solenoid that generates a field of 4 Tesla and is able to store 2.7 gigajoules, enough energy to melt 18 tonnes of gold. The second is an enormous and completely novel toroidal magnet formed of eight superconducting coils, which also generate a magnetic field of 4 Tesla, surrounding a smaller solenoid.

The next generation of superconducting magnets for detectors, which will be even bigger and more powerful, is being developed in the context of preparations for major accelerator projects at CERN and elsewhere.

This text is published on the occasion of the conference EUCAS 2017 on superconductors and their applications​. It is based on the article entitled “Unique magnets”, which appeared in the September issue of the CERN Courier:


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

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

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

Related links:

Superconducting magnets:

Large Hadron Collider (LHC):



EUCAS 2017:

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

Images (mentioned), Text, Credits: CERN/Corinne Pralavorio.


Superconductors boost acceleration

CERN - European Organization for Nuclear Research logo.

September 20, 2017

Image above: The new superconducting crab cavities being assembled at CERN. These cavities will be used in the future High-Luminosity LHC to tilt the particle bunches before they collide. (Image: Jules Ordan/CERN).

Thanks to their amazing properties, superconductors have become a vital ally of particle physics. As well as using superconducting magnets to steer particles in the right direction, accelerators use superconducting cavities to accelerate them. During the EUCAS 2017 conference on superconductors and their applications, which is taking place this week in Geneva, many presentations are being made on this subject.

A radiofrequency accelerating cavity is basically a metal chamber in which electromagnetic waves generate an electrical field. As particles pass through the chamber, they receive an electrical impulse. Compared to traditional copper cavities, superconducting cavities generate very strong electrical fields. Those in the Large Hadron Collider (LHC), for example, generate an electrical field of 5 million volts per metre.

The first work on superconducting cavities for particle physics began in the 1960s. But it was not until the 1980s that they were actually used in an accelerator, an electron collider at Cornell University in the United States. Meanwhile, the designers working on the Large Electron-Positron Collider (LEP) at CERN were investigating the technology as a way of doubling the energy level of their machine. The 27-kilometre ring was fitted out with 280 such cavities, allowing the LEP to exceed 200 GeV in the 1990s. The LHC is equipped with similar cavities. The brand new XFEL synchrotron at the DESY laboratory in Germany is made up of no fewer than 800 accelerating cavities, which rely heavily on the work carried out in the 1990s by the TESLA collaboration.

Large Hadron Collider (LHC). Animation Credit: CERN

Today, the development of new superconducting cavities continues, particularly at CERN, where so-called “crab cavities” are under development to tilt particle bunches before they collide in the High-Luminosity LHC. These cavities will help to maximise overlapping of the beams in order to increase the probability of collisions each time they meet, otherwise known as luminosity. At Fermilab, the Cornell Laboratory and SLAC in the United States, new coatings are also being studied to improve performance even further.

This text is based on the article entitled “Souped up RF”, which appeared in the September issue of the CERN Courier:


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

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

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

Related links:

Superconducting cavities:

EUCAS 2017:

Large Hadron Collider (LHC):

Large Electron-Positron Collider (LEP):

The brand new XFEL synchrotron:

DESY laboratory:

High-Luminosity LHC:

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

Image (mentioned), Animation (mentioned), Text, Credits: CERN/Corinne Pralavorio.


Weekly Recap From the Expedition Lead Scientist, week of September 11, 2017

ISS - Expedition 53 Mission patch.

Sept. 20, 2017

(Highlights: Week of September 11, 2017) - NASA astronauts Mark Vande Hei, Joe Acaba and Russian cosmonaut Alexander Misurkin launched to the International Space Station on Sept. 12, where they joined Expedition 53 Commander Randy Bresnik of NASA and Flight Engineers Sergey Ryazanskiy of Roscosmos and Paolo Nespoli of ESA (European Space Agency) to continue scientific research aboard the orbiting laboratory.

As Hurricane Irma lashed the state of Florida, an investigation in orbit took data points that could improve weather prediction models and help emergency responders and coastal residents better prepare for future storms. The Cyclone Intensity Measurements from the International Space Station (Tropical Cyclone) investigation captures images and data of major storms approaching landfall. The investigation uses a specialized, automated camera and other instruments to acquire data about the storms through one of the portals on the space station.

Image above: Crew members captured this image of the aurora borealis and a lightning storm as the International Space Station flew over Canada. Image Credit: NASA.

Scientists are demonstrating new techniques for accurate real-time measurement of the intensities of strong tropical cyclones by using passive instrumentation from low-Earth orbit. This method requires measurements of the temperature of the top of the eye wall clouds of the storm and the height of these clouds above sea level. Combined with information on sea-level surface temperatures and air pressure, scientists can more accurately predict the wind speed, strength and intensities of cyclones prior to landfall. This information could assist emergency responders and coastal residents to better prepare for oncoming storms.

Nespoli continued a week-long run of the Magnetic Flux Experiment (MAGVECTOR) investigation. This ESA study looks in to how Earth's magnetic field interacts with an electrical conductor through extremely sensitive magnetic sensors placed around and above a conductor.

Earth's magnetic field is constantly flowing around us. Aside from protecting us from solar winds, it also makes a compass work and birds find their destination when migrating. This same force can interact and interfere with equipment and experiments on the space station. Using magnetic sensors placed near an electrical conductor, MAGVECTOR will help scientists gain insight into how the field influences conductors. The results will help protect future station experiments and electric equipment, and could offer insights into how magnetic fields influence electrical conductors -- the backbone of current technology.

Image above: The Soyuz spacecraft carrying three new crew members approaches the International Space Station on Sept. 12. Image Credit: NASA.

Scientists are also testing other methods to keep the computer systems on the space station functional, especially during high radiation events. Some of the computers on the orbiting laboratory are commercial off-the-shelf (COTS) systems that any consumer can purchase. During the High-Performance COTS Computer System on the ISS (Spaceborne Computer) investigation, scientists want to test if using software to lower the power and, by extension, the speed of the computers can protect the systems without expensive, time-consuming or bulky protective shielding.

Radiation is likely to have unanticipated effects on complex computer systems. Radiation-resistant computers can improve the reliability of these systems in space. This investigation can help identify critical failure points and potential software patches to prevent them. Radiation events like solar flares can also pose risks to computing resources on Earth, such as mobile phone towers and traffic monitoring systems. This research could identify solutions to minimize radiation risk for these systems as well.

A collection of life-sciences investigations were prepared to return on the Dragon spacecraft Sept. 17. Among them was the Cardiac Myocytes investigation, using microgravity to examine how stem cells develop into specific cells – heart cells in this case. This study will help us learn how stem cells develop and demonstrate ways to use space as a production facility for medical and regenerative therapies. It could also help reduce the risk of heart failure and other diseases.

Image above: The signal received from a black hole-companion star celestial event as captured by the Neutron Star Interior Composition Explorer investigation on the space station. The cycle of rays received by NICER as the black hole consumes the star resembles a heartbeat from an electrocardiogram. Image Credit: NASA.

Another investigation is returning live cultures from the station that will help an investigation into 3D bioprinted cardiac and vascular cells. The Maturation Study of Biofabricated Myocyte Construct looks in to the results of developing these cells in microgravity, much like they may grow when the cells are first forming. Scientists believe bioprinted cells will grow and organize more efficiently in space compared to identical cells grown on the ground. The eventual goal is to use tissue from a patient to bioprint complex structures in space, establishing a system to print patient specific tissues and organs in space for transplant back on Earth.

The Neutron Star Interior Composition Explorer (NICER) investigation on the space station observed a compelling celestial event. The study captured X-Ray readings of a companion star in the final stages of descending toward a black hole. The black hole is approximately 10 times larger than our sun. The cycle of X-Ray brightness and dimming as the black hole devours the sun resembles a heart-beat on an electrocardiogram. Further study of this particular pairing will help provide more data on the physics of our universe, including identifying neutron stars and using them to help create accurate navigation systems for spacecraft – like a celestial GPS.

Space to Ground: Full Strength: 09/15/2017

Video above: NASA's Space to Ground is a weekly update on what is happening on the International Space Station. Social media users can post with #spacetoground to ask questions or make a comment. Video Credit: NASA.

Progress was made on other investigations this week, including: Combustion Integration Rack (CIR), Long Duration Sorbent Testbed (LDST), Lighting Effects, Lung Tissue, FIR LMM, Fine Motor Skills, ADSEP, Rodent Research-9, ISS Ham, Cool Flames, Advanced Research Thermal Passive Exchange (ARTE), Tangolab, and SABL2.

Related links:

Tropical Cyclone:

Magnetic Flux Experiment (MAGVECTOR):

Spaceborne Computer:

Cardiac Myocytes:

Neutron Star Interior Composition Explorer (NICER):

Combustion Integration Rack (CIR):

Long Duration Sorbent Testbed (LDST):

Lighting Effects:

Lung Tissue:



Fine Motor Skills:


Rodent Research-9:

ISS Ham:

Cool Flames:

Advanced Research Thermal Passive Exchange (ARTE):


Space Station Research and Technology:

International Space Station (ISS):

Images (mentioned), Video (mentioned), Text, Credits: NASA/Kristine Rainey/John Love, Lead Increment Scientist Expeditions 53 & 54.

Best regards,