Magnetar Formation Mystery Solved?

ESO - European Southern Observatory logo.

14 May 2014

Artist’s impression of the magnetar in the star cluster Westerlund 1

Magnetars are the bizarre super-dense remnants of supernova explosions. They are the strongest magnets known in the Universe — millions of times more powerful than the strongest magnets on Earth. A team of European astronomers using ESO’s Very Large Telescope (VLT) now believe they’ve found the partner star of a magnetar for the first time. This discovery helps to explain how magnetars form — a conundrum dating back 35 years — and why this particular star didn’t collapse into a black hole as astronomers would expect.

When a massive star collapses under its own gravity during a supernova explosion it forms either a neutron star or black hole. Magnetars are an unusual and very exotic form of neutron star. Like all of these strange objects they are tiny and extraordinarily dense — a teaspoon of neutron star material would have a mass of about a billion tonnes — but they also have extremely powerful magnetic fields. Magnetar surfaces release vast quantities of gamma rays when they undergo a sudden adjustment known as a starquake as a result of the huge stresses in their crusts.

Image above: The star cluster Westerlund 1 and the positions of the magnetar and its probable former companion star.

The Westerlund 1 star cluster [1], located 16 000 light-years away in the southern constellation of Ara (the Altar), hosts one of the two dozen magnetars known in the Milky Way. It is called CXOU J164710.2-455216 and it has greatly puzzled astronomers.

“In our earlier work (eso1034) we showed that the magnetar in the cluster Westerlund 1 (eso0510) must have been born in the explosive death of a star about 40 times as massive as the Sun. But this presents its own problem, since stars this massive are expected to collapse to form black holes after their deaths, not neutron stars. We did not understand how it could have become a magnetar,” says Simon Clark, lead author of the paper reporting these results.

The star cluster Westerlund 1

Astronomers proposed a solution to this mystery. They suggested that the magnetar formed through the interactions of two very massive stars orbiting one another in a binary system so compact that it would fit within the orbit of the Earth around the Sun. But, up to now, no companion star was detected at the location of the magnetar in Westerlund 1, so astronomers used the VLT to search for it in other parts of the cluster. They hunted for runaway stars — objects escaping the cluster at high velocities — that might have been kicked out of orbit by the supernova explosion that formed the magnetar. One star, known as Westerlund 1-5 [2], was found to be doing just that.

“Not only does this star have the high velocity expected if it is recoiling from a supernova explosion, but the combination of its low mass, high luminosity and carbon-rich composition appear impossible to replicate in a single star — a smoking gun that shows it must have originally formed with a binary companion,” adds Ben Ritchie (Open University), a co-author on the new paper.

Wide-field view of the sky around the star cluster Westerlund 1

This discovery allowed the astronomers to reconstruct the stellar life story that permitted the magnetar to form, in place of the expected black hole [3]. In the first stage of this process, the more massive star of the pair begins to run out of fuel, transferring its outer layers to its less massive companion — which is destined to become the magnetar — causing it to rotate more and more quickly. This rapid rotation appears to be the essential ingredient in the formation of the magnetar’s ultra-strong magnetic field.

In the second stage, as a result of this mass transfer, the companion itself becomes so massive that it in turn sheds a large amount of its recently gained mass. Much of this mass is lost but some is passed back to the original star that we still see shining today as Westerlund 1-5.

Flying through the young star cluster Westerlund 1 (artist's impression)

“It is this process of swapping material that has imparted the unique chemical signature to Westerlund 1-5 and allowed the mass of its companion to shrink to low enough levels that a magnetar was born instead of a black hole — a game of stellar pass-the-parcel with cosmic consequences!” concludes team member Francisco Najarro (Centro de Astrobiología, Spain).

It seems that being a component of a double star may therefore be an essential ingredient in the recipe for forming a magnetar. The rapid rotation created by mass transfer between the two stars appears necessary to generate the ultra-strong magnetic field and then a second mass transfer phase allows the magnetar-to-be to slim down sufficiently so that it does not collapse into a black hole at the moment of its death.

Notes:

[1] The open cluster Westerlund 1 was discovered in 1961 from Australia by Swedish astronomer Bengt Westerlund, who later moved from there to become ESO Director in Chile (1970–74). This cluster is behind a huge interstellar cloud of gas and dust, which blocks most of its visible light. The dimming factor is more than 100 000, and this is why it has taken so long to uncover the true nature of this particular cluster.

Westerlund 1 is a unique natural laboratory for the study of extreme stellar physics, helping astronomers to find out how the most massive stars in the Milky Way live and die. From their observations, the astronomers conclude that this extreme cluster most probably contains no less than 100 000 times the mass of the Sun, and all of its stars are located within a region less than 6 light-years across. Westerlund 1 thus appears to be the most massive compact young cluster yet identified in the Milky Way galaxy.

All the stars so far analysed in Westerlund 1 have masses at least 30–40 times that of the Sun. Because such stars have a rather short life — astronomically speaking — Westerlund 1 must be very young. The astronomers determine an age somewhere between 3.5 and 5 million years. So, Westerlund 1 is clearly a newborn cluster in our galaxy.

[2] The full designation for this star is Cl* Westerlund 1 W 5.

[3] As stars age, their nuclear reactions change their chemical make-up — elements that fuel the reactions are depleted and the products of the reactions accumulate. This stellar chemical fingerprint is first rich in hydrogen and nitrogen but poor in carbon and it is only very late in the lives of stars that carbon increases, by which point hydrogen and nitrogen will be severely reduced — it is thought to be impossible for single stars to be simultaneously rich in hydrogen, nitrogen and carbon, as Westerlund 1-5 is.

More information:

The research presented in this ESO Press Release will soon appear in the research journal Astronomy and Astrophysics (“A VLT/FLAMES survey for massive binaries in Westerlund 1: IV.Wd1-5 binary product and a pre-supernova companion for the magnetar CXOU J1647-45” by J. S. Clark et al.). The same team published a first study of this object in 2006 (“A Neutron Star with a Massive Progenitor in Westerlund 1” by M. P. Muno et al., Astrophysical Journal, 636, L41).

The team is composed of Simon Clark and Ben Ritchie (The Open University, UK), Francisco Najarro (Centro de Astrobiología, Spain), Norbert Langer (Universität Bonn, Germany, and Universiteit Utrecht, the Netherlands) and Ignacio Negueruela (Universidad de Alicante, Spain).

The astronomers used the FLAMES instrument on ESO’s Very Large Telescope at Paranal, Chile to study the stars in the Westerlund 1 cluster.

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:

Research paper: http://www.eso.org/public/archives/releases/sciencepapers/eso1415/eso1415a.pdf

Photos of the VLT: http://www.eso.org/public/images/archive/category/paranal/

Images, Video, Text, Credits: ESO/L. Calçada/Digitized Sky Survey 2/Acknowledgment: Davide De Martin.

Best regards, Orbiter.ch

Expedition 39 Crew Lands Safely

ROSCOSMOS - Soyuz TMA-1M Mission patch.

May 13, 2014

The Soyuz TMA-11M spacecraft landing in the sky of Kazakhstan

The Expedition 39 crew returned to Earth Tuesday after 188 days in space, completing a journey of over 79-million miles and more than 3,000 orbits of the Earth since launching to the International Space Station back in November.

The Soyuz TMA-11M spacecraft carrying Expedition 39 Commander Koichi Wakata of the Japan Aerospace Exploration Agency, Soyuz Commander Mikhail Tyurin of Roscosmos, the Russian Federal Space Agency and Flight Engineer Rick Mastracchio of NASA landed in the steppe of Kazakhstan southeast of Dzhezkazgan at 9:58 p.m. (7:58 a.m. Wednesday, Kazakh time). Helicopters carrying the Russian recovery teams and NASA personnel reached the landing site shortly afterward to assist the crew and conduct medical examinations.

 Expedition 39 back on solid ground

The Soyuz undocked from the Rassvet module on the Earth-facing side of the station at 6:36 p.m. as the station soared 261 statute miles over Mongolia. The 4-minute, 41-second deorbit burn beginning at 9:04 p.m. slowed the Soyuz for its decent into the Earth’s atmosphere and its parachute-assisted landing.

Image above: The Expedition 39 crew adjusts to the full force of Earth's gravity shortly after landing in Kazakhstan aboard their Soyuz spacecraft. Image Credit: NASA TV.

The undocking marked the end of Expedition 39 and the start of Expedition 40 under the command of NASA astronaut Steve Swanson. Wakata, the first Japanese commander of the station, passed the helm of the orbiting complex over to Swanson during a change of command ceremony Monday afternoon. After making their final farewells, Wakata, Mastracchio and Tyurin boarded their Soyuz, and the crews closed the hatches between the vehicles at 3:26 p.m. Tuesday.

Image above: The Soyuz TMA-11M spacecraft backs away from the International Space Station shortly after undocking. Image Credit: NASA TV.

Swanson and his crewmates, Alexander Skvortsov and Oleg Artemyev of Roscosmos, will operate the station as a three-person crew for two weeks until the arrival of three new crew members -- Reid Wiseman of NASA, Max Suraev of Roscosmos and Alexander Gerst of the European Space Agency. The trio of new flight engineers, who are wrapping up pre-flight activities in Star City, Russia, will fly to the Baikonur Cosmodrome in Kazakhstan on Thursday to begin the homestretch of preparations for their May 28 launch to the station.

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

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

Cheers, Orbiter.ch

Station’s Expedition 39 Crew Heading Back to Earth

ISS - Expedition 39 Mission patch / ROSCOSMOS - Soyuz TMA-11M Mission patch.

May 13, 2014

Three Expedition 39 crew members are on their way back to Earth after more than six months aboard the International Space Station.

Image above: A Russian Soyuz spacecraft is seen docked to the International Space Station, as photographed by one of the Expedition 39 crew members aboard the orbital outpost.Image Credit: NASA.

Soyuz Commander Mikhail Tyurin of Roscosmos, the Russian Federal Space Agency Expedition 39 Commander Koichi Wakata of the Japan Aerospace Exploration Agency and Flight Engineer Rick Mastracchio of NASA undocked their Soyuz TMA-11M spacecraft from the Rassvet module on the Earth-facing side of the station at 6:36 p.m. EDT. At the time of undocking the complex was orbiting 261 statute miles over Mongolia.

Station Crewmates Board Soyuz for Journey Home

A deorbit burn at 9:04 p.m. will put the Soyuz on track for a parachute-assisted landing in the steppe of Kazakhstan southeast of Dzhezkazgan at 9:58 p.m. (7:58 a.m. Wednesday, Kazakh time). The landing will complete a journey of over 79 million statute miles and more than 3,000 orbits of the Earth for the trio since launching to the station from the Baikonur Cosmodrome in Kazakhstan back on Nov. 7.

Image above: Soyuz Commander Mikhail Tyurin and Expedition 39 Commander Koichi Wakata close the hatch to Soyuz as they and Flight Engineer Rick Mastracchio prepare for the return to Earth after more than six months aboard the International Space Station. Image Credit: NASA TV.

Learn more about Soyuz landings: http://www.nasa.gov/mission_pages/station/structure/elements/soyuz/landing.html

Live NASA Television coverage of the Expedition 39 landing begins at 8:45 p.m.

Watch NASA TV: http://www.nasa.gov/ntv

The undocking marked the end of Expedition 39 and the start of Expedition 40 under the command of NASA astronaut Steve Swanson. Wakata, the first Japanese commander of the station, passed the helm of the orbiting complex over to Swanson during a change of command ceremony Monday afternoon. After making their final farewells, Wakata, Mastracchio and Tyurin boarded their Soyuz, and the crews closed the hatches between the vehicles at 3:26 p.m. Tuesday.

Expedition 39 Soyuz Undocks from Station

Swanson and his crewmates, Alexander Skvortsov and Oleg Artemyev of Roscosmos, will operate the station as a three-person crew for two weeks until the arrival of three new crew members -- Reid Wiseman of NASA, Max Suraev of Roscosmos and Alexander Gerst of the European Space Agency. The trio of new flight engineers, who are wrapping up pre-flight activities in Star City, Russia, will fly to Baikonur on Thursday to begin the homestretch of preparations for their May 28 launch to the station.

Image above: This Russian control panel shows the view of the International Space Station from the departing Soyuz spacecraft. Image Credit: NASA TV.

Samples from the ongoing microbiome investigation will return on the Soyuz TMA-11M. The microbiome study looks at the impact of space travel on the immune system and on human microbiomes – microbes living in and on the human body at any given time. Samples from crew members’ bodies and the space station environment are taken periodically to monitor changes in the immune system and microbiomes. The results of this study may add to research on health impacts to people who live and work in extreme environments on Earth, and help with research on early disease detection, metabolic function and immune system deficiency.

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

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

Best regards, Orbiter.ch

NASA-UCI Study Indicates Loss of West Antarctic Glaciers Appears Unstoppable

NASA logo / University of California Irvine (UCI) logo.

May 12, 2014

A new study by researchers at NASA and the University of California, Irvine, finds a rapidly melting section of the West Antarctic Ice Sheet appears to be in an irreversible state of decline, with nothing to stop the glaciers in this area from melting into the sea.

The study presents multiple lines of evidence, incorporating 40 years of observations that indicate the glaciers in the Amundsen Sea sector of West Antarctica "have passed the point of no return," according to glaciologist and lead author Eric Rignot, of UC Irvine and NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. The new study has been accepted for publication in the journal Geophysical Research Letters.

These glaciers already contribute significantly to sea level rise, releasing almost as much ice into the ocean annually as the entire Greenland Ice Sheet. They contain enough ice to raise global sea level by 4 feet (1.2 meters) and are melting faster than most scientists had expected. Rignot said these findings will require an upward revision to current predictions of sea level rise.

Image above: Glaciers in West Antarctica’s Amundsen Sea Embayment have “passed the point of no return” according to new research based on three different lines of evidence. Image Credit: NASA/Eric Rignot.

"This sector will be a major contributor to sea level rise in the decades and centuries to come," Rignot said. "A conservative estimate is it could take several centuries for all of the ice to flow into the sea."

Three major lines of evidence point to the glaciers' eventual demise: the changes in their flow speeds, how much of each glacier floats on seawater, and the slope of the terrain they are flowing over and its depth below sea level. In a paper in April, Rignot’s research group discussed the steadily increasing flow speeds of these glaciers over the past 40 years. This new study examines the other two lines of evidence.

The glaciers flow out from land to the ocean, with their leading edges afloat on the seawater. The point on a glacier where it first loses contact with land is called the grounding line. Nearly all glacier melt occurs on the underside of the glacier beyond the grounding line, on the section floating on seawater.

Just as a grounded boat can float again on shallow water if it is made lighter, a glacier can float over an area where it used to be grounded if it becomes lighter, which it does by melting or by the thinning effects of the glacier stretching out. The Antarctic glaciers studied by Rignot's group have thinned so much they are now floating above places where they used to sit solidly on land, which means their grounding lines are retreating inland.

"The grounding line is buried under a thousand or more meters of ice, so it is incredibly challenging for a human observer on the ice sheet surface to figure out exactly where the transition is," Rignot said. “This analysis is best done using satellite techniques."

The team used radar observations captured between 1992 and 2011 by the European Earth Remote Sensing (ERS-1 and -2) satellites to map the grounding lines' retreat inland. The satellites use a technique called radar interferometry, which enables scientists to measure very precisely -- within less than a quarter of an inch -- how much Earth's surface is moving. Glaciers move horizontally as they flow downstream, but their floating portions also rise and fall vertically with changes in the tides. Rignot and his team mapped how far inland these vertical motions extend to locate the grounding lines.

The accelerating flow speeds and retreating grounding lines reinforce each other. As glaciers flow faster, they stretch out and thin, which reduces their weight and lifts them farther off the bedrock. As the grounding line retreats and more of the glacier becomes waterborne, there's less resistance underneath, so the flow accelerates.

West Antarctic Glaciers in Irreversible Decline

Slowing or stopping these changes requires pinning points -- bumps or hills rising from the glacier bed that snag the ice from underneath. To locate these points, researchers produced a more accurate map of bed elevation that combines ice velocity data from ERS-1 and -2 and ice thickness data from NASA's Operation IceBridge mission and other airborne campaigns. The results confirm no pinning points are present upstream of the present grounding lines in five of the six glaciers. Only Haynes Glacier has major bedrock obstructions upstream, but it drains a small sector and is retreating as rapidly as the other glaciers.

The bedrock topography is another key to the fate of the ice in this basin. All the glacier beds slope deeper below sea level as they extend farther inland. As the glaciers retreat, they cannot escape the reach of the ocean, and the warm water will keep melting them even more rapidly.

The accelerating flow rates, lack of pinning points and sloping bedrock all point to one conclusion, Rignot said.

"The collapse of this sector of West Antarctica appears to be unstoppable," he said. "The fact that the retreat is happening simultaneously over a large sector suggests it was triggered by a common cause, such as an increase in the amount of ocean heat beneath the floating sections of the glaciers. At this point, the end of this sector appears to be inevitable."

Because of the importance of this part of West Antarctica, NASA's Operation IceBridge will continue to monitor its evolution closely during this year's Antarctica deployment, which begins in October. IceBridge uses a specialized fleet of research aircraft and the most sophisticated suite of science instruments ever assembled to characterize changes in thickness of glaciers, ice sheets and sea ice.

For additional images and video related to this new finding, visit: http://go.nasa.gov/1m6YZSf

For additional information on the West Antarctic Ice Sheet and its potential contribution to sea level rise, visit: http://go.nasa.gov/1oIfSlO

For more information on Operation IceBridge, visit: http://www.nasa.gov/icebridge

The California Institute of Technology in Pasadena manages JPL for NASA.

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 see 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

Images, Video, Text, Credits: NASA / Steve Cole / JPL / Alan Buis / University of California, Irvine / Janet Wilson / American Geophysical Union / Peter Weiss / NASA Earth Science News Team, written by Carol Rasmussen.

Greetings, Orbiter.ch

DEM L241: Hardy Star Survives Supernova Blast

NASA - Chandra X-ray Observatory patch.

May 12, 2014

DEM L241: Hardy Star Survives Supernova Blast

Video above: Astronomers have found evidence for a companion star that survived the blast of a supernova explosion. The supernova remnant is called DEM L241 and is found in the Large Magellanic Cloud, a small neighboring galaxy to the Milky Way. (NASA/CXC/A. Hobart).

 DEM L241. Image Credits: NASA / Chandra X-ray Observatory / CXC.

For more information about Chandra X-ray Observatory, visit: http://www.nasa.gov/mission_pages/chandra/main/

Image (mentioned), Video (mentioned), Text, Credit: NASA.

Cheers, Orbiter.ch

A Look at the Numbers as Hubble Space Telescope Enters its 25th Year

NASA - Hubble Space Telescope patch.

May 12, 2014

Image above: The Hubble Telescope as seen from NASA Space Shuttle STS-125 in May 2009. The Hubble Space Telescope was reborn with Servicing Mission 4 (SM4), the fifth and final servicing of the orbiting observatory. Image Credit: NASA.

On April 24, 1990, the space shuttle Discovery lifted off from Earth with the Hubble Space Telescope nestled securely in its bay. The following day, Hubble was released into space, ready to peer into the vast unknown of space.

NASA's Hubble Space Telescope recently marked its 24th year in space and to celebrate its 25th year, NASA is taking a look at some of the amazing statistics generated by the world-famous telescope.

Hubble has reinvigorated and reshaped our perception of space and uncovered a universe where almost anything seems possible within the laws of physics. Hubble has revealed properties of space and time that for most of human history were only probed in the imaginations of scientists and philosophers alike. Today, Hubble continues to provide views of cosmic wonders never before seen and is at the forefront of many new discoveries.

Hubble orbiting Earth. Video Credit: ESA

Shortly after Hubble was deployed in 1990, the observatory's primary mirror was discovered to have a flaw that affected the clarity of the telescope's early images. Astronauts repaired Hubble in December 1993. Including that trip, there have been five astronaut servicing missions to Hubble. The first servicing mission occurred Dec. 2-13, 1993. Subsequent servicing missions occurred on Feb. 11-21, 1997; Dec.19-27, 1999; March 1-12, 2002; and May 11-24, 2009.

Here are some statistics on the Hubble as of its 24th anniversary on April 24, 2014:


-    Hubble captures pictures of stars, planets and galaxies from its orbit around Earth while moving at 17,500 mph.
    
-    Hubble has made more the 1 million observations since its mission began in 1990.
    

-    Hubble has observed 38,000 celestial targets.
    
-    Hubble has orbited Earth more than 3 billion miles along a circular low-Earth orbit of about 350 miles altitude
    
-    As of Hubble's 24th anniversary in April 2014, Hubble's observations have taken up more than 100 terabytes of data.
    
-    Hubble currently generates 844 gigabytes of data per month.
    
-    About 4,000 astronomers from all over the world have used the telescope to probe the universe.
    
-    Astronomers using Hubble data have published more than 11,000 scientific papers, making it one of the most productive scientific instruments ever built.
    
-    Hubble weighs 24,500 pounds -- as much as two full-grown elephants.
    
-    Hubble's primary mirror is 2.4 meters (7 feet, 10.5 inches) across.
    
-    Hubble is 13.3 meters (43.5 feet) long -- the length of a large school bus.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy Inc., in Washington.

For images and more information about Hubble, visit:http://www.nasa.gov/hubble and http://www.spacetelescope.org/

Image (mentioned), Video (mentioned), Text, Credit: NASA's Goddard Space Flight Center / Rob Gutro.

Best regards, Orbiter.ch

Expedition 39 Trio Wrapping Up Six Months on Station

ISS - Expedition 39 Mission patch.

May 12, 2014

On the eve of the return to Earth of three crew members after six months in space, the International Space Station’s Expedition 39 crew tackled spacesuit maintenance as well as a full morning of biomedical research for the station’s departing commander on Monday.

Commander Koichi Wakata of the Japan Aerospace Exploration Agency, Flight Engineer Rick Mastracchio of NASA and Soyuz commander Mikhail Tyurin of Roscosmos, the Russian Federal Space Agency, will wrap up 188 days in space when they depart Tuesday aboard the Soyuz TMA-11M spacecraft that brought them to the station back in November. The trio will undock their Soyuz from the station at 6:36 p.m. EDT for a landing southeast of the remote town of Dzhezkazgan in Kazakhstan at 9:58 p.m. (7:58 a.m. May 14, Kazakh time).

Image above: Flight Engineers Rick Mastracchio (top) and Steve Swanson replace a fan pump separator inside a U.S. spacesuit aboard the International Space Station. Image Credit: NASA TV.

NASA Television will provide complete coverage of the Expedition 39 crew’s return to Earth, from farewells to landing.

View NASA TV schedule of events: http://www.nasa.gov/press/2014/may/nasa-television-to-air-expedition-39-crews-return-from-space-station/

Watch NASA TV: http://www.nasa.gov/ntv

Expedition 40, under the command of NASA astronaut Steve Swanson, will formally begin aboard the station when the Soyuz carrying Wakata, Mastracchio and Tyurin undocks. Swanson and his crewmates, Flight Engineers Alexander Skvortsov and Oleg Artemyev of Roscosmos, will operate the station as a three-person crew for two weeks until the arrival of three new crew members. Reid Wiseman of NASA, Max Suraev of Roscosmos and Alexander Gerst of the European Space Agency are scheduled to launch from the Baikonur Cosmodrome in Kazakhstan on May 28.

Wrapping up his tour of duty as the first Japanese commander of the orbital complex, Wakata passed the station’s helm to Swanson during a change of command ceremony Monday afternoon.

Image above: Expedition 39 Commander Koichi Wakata (right) passes the helm of the International Space Station to Expedition 40 Commander Steve Swanson during a change of command ceremony Monday. Image Credit: NASA TV.

Wakata spent much of his final full day in space working inside the station’s Columbus laboratory as he participated in the BP Reg experiment. This is a Canadian Space Agency medical study that seeks to understand the causes of fainting and dizziness seen in some astronauts when they return to Earth following a long-duration mission. Results from this experiment will not only help researchers understand and mitigate these unwanted effects for returning astronauts, but it also will have direct benefits for people on Earth – particularly those predisposed to falls and resulting injuries, as seen in the elderly.

Read more about BP Reg: http://www.nasa.gov/mission_pages/station/research/experiments/66.html

Meanwhile inside the Quest airlock, Mastracchio and Swanson replaced a fan pump separator inside one of the U.S. spacesuits. Contamination of the fan pump separator in a different suit worn by Flight Engineer Luca Parmitano during a July 2013 spacewalk resulted in an incident that brought an early end to that excursion. This contamination clogged several small holes that prevented water from flowing properly, causing water to back up and flow into the space suit’s air system and enter the helmet.

Image above: Commander Koichi Wakata works with the BP Reg experiment inside the International Space Station's Columbus laboratory. Image Credit: NASA TV.

On the Russian side of the complex, Tyurin completed his final session of Lower Body Negative Pressure Training to condition himself for Tuesday’s landing. Artemyev assisted the veteran cosmonaut as he donned 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 cosmonauts will react to the full force of Earth’s gravity at the end of their mission.

Afterward, Tyurin focused on packing crew items and science cargo inside his Soyuz spacecraft for return to Earth.

Artemyev meanwhile initialized and deployed new dosimeters for the Matryoshka experiment. Named after the traditional Russian nesting dolls, Matryoshka analyzes the radiation environment onboard the station.

Skvortsov downloaded data from an earthquake-monitoring experiment known as Seismoprognoz. He also photographed samples from the Struktura protein crystal growth study.

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

Images (mentioned), Text, Credit: NASA.

Greetings, Orbiter.ch