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Sonntag, 15. Januar 2017 - 21:55 Uhr

Astronomie - WVU hilft, die Entstehung von mysteriösen, ultra-mächtigen Ausbrüchen im Weltraum zu finden

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WVU helps find origins of mysterious, ultra-powerful bursts in space

You can’t see it, but billions of light years away cosmic flash bulbs are popping and no one knows why.

Fast radio bursts, brilliant and intense flashes of energy that blaze for a millisecond and then disappear, have puzzled scientists for years, but West Virginia University astronomers are helping to find the celestial bread crumbs that will help lead scientists to answers about this mysterious phenomenon.

Sarah Burke-Spolaor, assistant professor in the physics and astronomydepartment of the Eberly College of Arts and Sciences, and Maura McLaughlin, Eberly Distinguished Professor of Physics and Astronomy, are leading members of a team that has pinpointed the location in the sky of one of these bursts for the first time, allowing scientists to determine the distance and home galaxy of one of these pulses of radio waves.

The new findings are featured as the cover story in the Jan. 5, 2017 issue of the scientific journal Nature as well as in companion papers in Astrophysical Journal Letters. A team of astronomers, including Burke-Spolaor, who is co-author on the paper, also presented the findings at the Astronomical Society’s meeting this week in Grapevine, Texas.

Using the National Science Foundation’s Karl G. Jansky Very Large Array, a multi-antenna radio telescope that has the ability to see fine details, scientists now know that the burst came from a dwarf galaxy more than 3 billion light years from Earth. Burke-Spolaor developed the real-time fast radio burst detector at the Very Large Array as a postdoctoral Jansky Fellow.

“For the first time, we have seen how truly remote and bright these bursts are. When they flash, just for an instant they far outshine their whole host galaxy,” Burke-Spolaor said. “In fact, the host galaxy was so faint that we needed both excellent burst localization and deep-sky optical imaging to pin the burst to its host.”

A needle in a haystack
Fast radio bursts are short-lived (millisecond) bursts of radio waves that pack a phenomenally energetic punch. The intense explosions of energy have been seen from many directions on the sky and come from great distances.

The first burst was discovered in 2007 by WVU physics and astronomy professor Duncan Lorimer, his then-undergraduate student David Narkevic, and McLaughlin while scouring archived data from Australia’s Parkes Radio Telescope.

Since then, fewer than two dozen bursts have been documented, but scientists still believe that these bursts occur by the thousands each day.

“In addition to being hard to find due to their short durations, fast radio bursts have so far been very hard to localize with single radio dishes which has made it very hard to say conclusively where they are coming from,” Lorimer said.

The ephemeral nature of these events has made it challenging for scientists to detect them or pin down how and where they were formed. Theories have ranged from a star exploding in a supernova to the far-fetched alien communication.

But recently, astronomers have come closer to discovering the mysterious origins.

A rare occurrence, again
In 2015, an international collaboration of scientists, including McLaughlin, made a valuable discovery that would allow scientists to observe the bursts more closely.

Fast radio bursts were generally thought to be single events that revealed few clues about their locations and sources, but in 2015 an international collaboration of scientists examined data from the Arecibo Radio Telescope in Puerto Rico that showed repeating bursts attributed to one specific fast radio burst.

“We have detected dozens of radio bursts with Arecibo, the Green Bank Telescope in West Virginia, and now the Very Large Array and the Effelsberg Telescope in Germany,” McLaughlin said.

“This is the only known fast radio burst from which repeated bursts have been detected, and it is not yet clear whether this object is representative of the broader population. If it is, however, the localization is a huge step forward in pinpointing their astrophysical origins.”

A far-off place
The repeating bursts from this object, named FRB 121102, allowed astronomers to watch for it using the Very Large Array.

In 83 hours of observing time over six months in 2016, the array detected nine bursts from FRB 121102.

“The Very Large Array data allowed us to narrow down the position very accurately,” Burke-Spolaor said.

With the precise array position, researchers were able to then use the Gemini North telescope in Hawaii to make a visible-light image that identified a faint dwarf galaxy at the location of the bursts. The Gemini observations also determined that the dwarf galaxy is more than 3 billion light years from Earth.

In addition to detecting the bright bursts from FRB 121102, the array observations also revealed an ongoing, persistent source of weaker radio emission in the same region.

Next, a team of observers used the multiple radio telescopes of the European VLBI Network, along with the 1,000-foot-diameter William E. Gordon Telescope of the Arecibo Observatory, and the NSF’s Very Long Baseline Array to determine the object’s position with even greater accuracy.

Using these highly sensitive, ultra-high precision instruments, scientists were able to determine that the source must be within 100 light years of each other, and the bursts and source are likely to be either the same object or physically associated with each other.

The top candidates, the astronomers suggested, are a neutron star – possibly a highly-magnetic one – surrounded by either material ejected by a supernova explosion or material ejected by a resulting pulsar, or an active nucleus in the galaxy with radio emission coming from jets of material emitted from the region surrounding a supermassive black hole.

Scientists believe that the bursts and the source are likely to be either the same object or somehow physically associated with each other.

“We are now searching for repeated bursts from other fast radio burst positions, including the original one discovered by our WVU team in 2007,” McLaughlin said. “With luck, more repeaters will be found and more localizations made.”

Fast radio bursts show great promise to understanding how matter is distributed in the universe.

“It’s not often we find a phenomenon so well-tuned to probing the universe,” Burke-Spolaor said. “Identifying more burst hosts will allow us to uniquely explore the host galaxies themselves, the space between galaxies, and other material that fast radio bursts travel through on their path to our telescopes.”

Quelle: West Virginia University.


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Sonntag, 15. Januar 2017 - 21:50 Uhr

Raumfahrt - A Very Alien Moon: NASA Celebrates 12th Anniversary of Huygens Landing on Titan

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Mosaic of images taken by Huygens during its descent to the surface of Titan, from an altitude of about 6 miles (10 kilometers). Image Credit: ESA/NASA/JPL/University of Arizona

Mosaic of images taken by Huygens during its descent to the surface of Titan, from an altitude of about 6 miles (10 kilometers). Riverbeds formed by liquid methane can be seen near the center of the image. Image Credit: ESA/NASA/JPL/University of Arizona

Twelve years ago today, one of the most incredible space missions ever was accomplished: the first landing of a probe on an alien moon. And this wasn’t just any moon, but Titan, largest moon of Saturn and one of the most fascinating worlds in the Solar System. Although much colder than Earth, Titan mimics some of the processes found here such as its hydrological cycle, but with liquid methane/ethane instead of water. Titan had been observed extensively by telescopes and from Saturnian orbit, but this was the first time the surface could be seen up close.

 

The Huygens lander, part of the Cassini mission to Saturn, was the first probe to ever attempt a landing on this alien world and it succeeded, in spades. Although not designed to last very long in the harsh environment, it sent back a wealth of information in the limited time it had.

Huygens was a project of the European Space Agency, which accompanied NASA’s Cassini spacecraft to Saturn. On Dec. 24, 2004, Huygens separated from the Cassini spacecraft and began its journey to Titan, which would take another 20 days.

On Jan. 14, 2005, it descended through Titan’s thick atmosphere, hanging beneath large parachutes. The probe measured the complex chemistry of the atmosphere as well as winds. Thousands of images were taken, showing the rugged highlands near its landing spot as well as drainage channels. The region looked very much like a coastline on Earth, with mountains and rivers; Huygens landed in what is thought to be an old lakebed or floodplain. But like other still-liquid lakes and seas elsewhere, that lake would have been composed of liquid methane/ethane, not water. On Titan’s surface, water ice is as hard as rock. Indeed, Huygens saw rounded boulders on the surface composed of water ice instead of rock. There was even some residual moisture still in the ground.

The first-ever images from the surface of Titan showed rounded boulders of rock-hard water ice strewn on an old riverbed or floodplain. Photo Credit: ESA

The first-ever images from the surface of Titan, taken by Huygens, showed rounded boulders of rock-hard water ice strewn on an old methane riverbed or floodplain. Photo Credit: ESA/NASA/JPL/University of Arizona

After only about 72 minutes, Huygens’ “mothership,” Cassini, dropped below the horizons, cutting off communications. But before then, the probe had already collected a ton of data and images from the surface.

To help celebrate this anniversary, some of the Cassini team members and other NASA leaders shared their thoughts about the mission:

“The Huygens descent and landing represented a major breakthrough in our exploration of Titan as well as the first soft landing on an outer-planet moon. It completely changed our understanding of this haze-covered ocean world,”
said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

“The Huygens images were everything our images from orbit were not. Instead of hazy, sinuous features that we could only guess were streams and drainage channels, here was incontrovertible evidence that at some point in Titan’s history – and perhaps even now – there were flowing liquid hydrocarbons on the surface. Huygens’ images became a Rosetta stone for helping us interpret our subsequent findings on Titan,” said Carolyn Porco, Cassini imaging team lead at Space Science Institute, Boulder, Colo.

“Cassini and Huygens have shown us that Titan is an amazing world with a landscape that mimics Earth in many ways. During its descent, the Huygens probe captured views that demonstrated an entirely new dimension to that comparison and highlights that there is so much more we have yet to discover. For me, Huygens has emphasized why it is so important that we continue to explore Titan,”
said Alex Hayes, a Cassini scientist at Cornell University, Ithaca, N.Y.

“Twelve years ago, a small probe touched down on an orangish, alien world in the outer solar system, marking humankind’s most distant landing to date. Studying Titan helps us tease out the potential of habitability of this tiny world and better understand the chemistry of the early Earth,”
said Jim Green, director of planetary science at NASA Headquarters, Washington.

As revealed by both Huygens and Cassini, Titan is one of the most enigmatic worlds in the Solar System, with rain, rivers, lakes, and seas of liquid methane/ethane, a thick nitrogen atmosphere with organic haze and clouds, vast dunes of organic material, and likely a subsurface ocean of water. Titan’s surface is literally covered in organic materials, thought to be similar to what existed on the early Earth.

Although extremely cold on Titan, some scientists believe that some form of primitive life could possibly exist there, in its lakes and seas or in the subsurface ocean. If so, it would probably be methane-based and different from anything seen on Earth. At the very least, Titan’s environment is thought to be quite similar to that of the early Earth, just before life started here. In many ways, Titan seems more like a planet than a moon, which made it such an enticing target for exploration.

While Titan has been a primary focus, Cassini has been busy exploring the entire Saturnian system since 2004. From the dozens of moons to the majestic rings of Saturn itself, there has been no lack of things to study; the Saturnian system is a very diverse collection of worlds and could be thought of as a miniature solar system in itself.

Radar image from Cassini of Ligeia Mare, the second-largest methane/ethane sea on Titan. Image Credit: NASA/JPL-Caltech/ASI/Cornell

Radar image from Cassini of Ligeia Mare, the second-largest methane/ethane sea on Titan. Image Credit: NASA/JPL-Caltech/ASI/Cornell

Seen by the human eye, Titan's surface is obscured by a thick global haze, but Cassini's radar can show features such as the methane rivers, lakes, seas and sand dunes. Image Credit: NASA/JPL-Caltech/University of Arizona/University of Idaho

Seen by the human eye, Titan’s surface is obscured by a thick global haze, but Cassini’s radar can show features such as the methane rivers, lakes, seas and sand dunes. Image Credit: NASA/JPL-Caltech/University of Arizona/University of Idaho

The moon Enceladus may be very small, but it has a subsurface ocean of water below its ice crust which can come up to the surface in the form of massive geysers through large cracks in the surface. Cassini has been able to sample these plumes directly, finding water vapor, ice particles, salts, and a variety of organic molecules. With evidence of hydrothermal activity on its ocean floor, Enceladus is now thought to be one of the best places to search for evidence of alien life. Cassini itself can’t determine whether life exists or not, that will require a follow-up mission. Concepts for such a mission are now being planned and designed.

Cassini recently began a series of Ring-Grazing Orbits, which will take it within the rings and closer to the planet itself as it prepares to end its mission this coming fall.

“This is it, the beginning of the end of our historic exploration of Saturn. Let these images – and those to come – remind you that we’ve lived a bold and daring adventure around the Solar System’s most magnificent planet,” said Carolyn Porco, Cassini imaging team lead at Space Science Institute in Boulder, Colo.

This phase of the mission began last Nov. 30, and will consist of 20 week-long orbits which pass very close to the outer edges of Saturn’s rings. In each pass, the spacecraft will also pass over the northern hemisphere just before “grazing” the rings. Subsequent passes will bring Cassini even closer to the edges of the rings, providing some of the closest images of the rings and the tiny moons which also orbit in that region.

A recent raw image from Cassini showing Saturn's north polar

A recent raw image from Cassini showing Saturn’s north polar “hexagon” wind pattern. Cassini has revolutionized our understanding of the entire Saturnian system. Photo Credit: NASA/JPL-Caltech

“We’re calling this phase of the mission Cassini’s Ring-Grazing Orbits, because we’ll be skimming past the outer edge of the rings,” said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “In addition, we have two instruments that can sample particles and gases as we cross the ringplane, so in a sense Cassini is also ‘grazing’ on the rings.”

During the Grand Finale phase, Cassini will plunge through the rings 22 times, through the 1,500-mile-wide (2,400-kilometer) gap between Saturn and its innermost ring, starting April 26, 2017. On Sept. 15, 2017, Cassini will plunge into Saturn’s atmosphere, on purpose, after it runs out of fuel. This fiery ending was decided upon in order to prevent the spacecraft from possibly colliding with any of the moons, in particular Enceladus or Cassini, where contamination could occur from possible microbes still alive onboard.

Although there are not yet any follow-up Cassini-style missions planned yet, scientists are working on new missions to return to Titan and Enceladus specifically. One such mission would study the potential habitability of Enceladus’ ocean and search for possible evidence of life itself. A mission to Titan would aim to land a boat-like probe in one of its methane/ethane seas; an even more ambitious future mission could be a submarine-type probe.

The proposed submarine, currently called the Titan Submarine Phase I Conceptual Design, would explore one of the moon’s exotic methane/ethane seas.  It was created by NASA Glenn’s COMPASS Team along with other researchers from Applied Research Lab. Appearance-wise, it resembles some older submarine models, but the technology involved would be much more advanced, necessary for working in such a cold, dark environment. From a recent paper:

“The vehicle would observe – and perhaps ultimately exploit – tidal currents in the sea, which follow a cycle once per Titan day, or 16 Earth days. When surfaced, as well as communicating with Earth, the vehicle would use a mast-mounted camera to observe the sea state and shoreline landscape, and would record meteorological observations. Measurement of the trace organic components of the sea, which perhaps may exhibit prebiotic chemical evolution, will be an important objective, and a benthic sampler would acquire and analyze sediment from the seabed. These measurements, and seafloor morphology via sidescan sonar, may shed light on the historical cycles of filling and drying of Titan’s seas. Models suggest Titan’s active hydrological cycle may cause the north part of Kraken to be ‘fresher’ (more methane-rich) than the south, and the submarine’s long traverse will explore these composition variations.”

There are currently two proposed follow-up missions to return to Enceladus: The Enceladus Life Finder (ELF) would fly through the plumes and analyze them, like Cassini, but with more advanced instruments, and the MASPEX instrument would analyze gas coming from the vents. ELF would be capable of finding and identifying amino acids, the building blocks of life. The Enceladus Icy Jet Analyzer would focus on solid particles in the plumes. Drilling through the ice to the ocean below would require a much more ambitious future mission, but just analyzing the water vapor escaping to space through the surface cracks would tell scientists a lot about the conditions in the ocean and whether life could be, or is, there.

Artist’s conception of the proposed Titan Submarine Phase I Conceptual Design. Much like submarines on Earth, the sub would explore the depths of one of Titan’s methane/ethane seas. Image Credit: NASA

Artist’s conception of the proposed Titan Submarine Phase I Conceptual Design. Much like submarines on Earth, the sub would explore the depths of one of Titan’s methane/ethane seas. Image Credit: NASA

“The plume of Enceladus is waiting for us. It could be the place where we find out if life had a second genesis in our own Solar System,” said planetary scientist Jonathan Lunine at Cornell University, in a talk at the American Geophysical Union meeting. “We must go back.”

These missions are still a ways off, but the first steps have already been taken. The 2016 budget proposal from the U.S. House Appropriations Committee called for the creation of an “Ocean Worlds Exploration Program” which would fund new missions to Europa, Enceladus, and Titan. From the proposal:

“Many of NASA’s most exciting discoveries in recent years have been made during the robotic exploration of the outer planets. The Cassini mission has discovered vast oceans of liquid hydrocarbons on Saturn’s moon Titan and a submerged salt water sea on Saturn’s moon Enceladus. The Committee directs NASA to create an Ocean World Exploration Program whose primary goal is to discover extant life on another world using a mix of Discovery, New Frontiers and flagship class missions consistent with the recommendations of current and future Planetary Decadal surveys.”

Returning to Titan and Enceladus would be two of the most exciting missions ever in planetary exploration. These are not just moons, they are worlds, with an incredible diversity of geology in alien yet eerily Earth-like environments. Huygens gave us our first close-up look at Titan. What else will we find when we return?

Quelle: AS


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Sonntag, 15. Januar 2017 - 19:45 Uhr

Raumfahrt-History - 1986 Space-Shuttle STS-61C Columbia Mission

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STS-61C
 
 

Mission: SATCOM KU-1
Space Shuttle: Columbia
Launch Pad: 39A 
Launch Weight: 256,003 pounds
Launched: January 12, 1986, 6:55:00 a.m. EST
Landing Site: Edwards Air Force Base, Calif.
Landing: January 18, 1986, 5:58:51 a.m. PST
Landing Weight: 210,161 pounds
Runway: 22 
Rollout Distance: 10,202 feet
Rollout Time: 59 seconds
Revolution: 98
Mission Duration: 6 days, 2 hours, 3 minutes, 51 seconds
Returned to KSC: January 23, 1986
Orbit Altitude: 212 nautical miles
Orbit Inclination: 28.5 degrees
Miles Traveled: 2.5 million 

Crew Members

                   STS-61C Crew Photo

Image above: STS-61C Crew photo with Commander Robert L. Gibson, Pilot Charles F. Bolden, Jr., Mission Specialists Franklin R. Chang-DiazSteven A. HawleyGeorge D. Nelson and Payload Specialists Robert J. Cenkerand Congressman Bill Nelson. Image Credit: NASA 

Launch/Landing Highlights

STS-61C Mission PatchThe launch set for December 18, 1985 was delayed one day when additional time needed to close out orbiter aft compartment. Another launch attempt on December 19 scrubbed at T- 14 seconds due to indication that the right solid rocket booster hydraulic power unit was exceeding the RPM redline speed limits. (This was later determined to be a false reading.) After an 18-day delay, a launch attempt January 6, 1986 halted at T-31 seconds due to the accidental draining of approximately 4,000 pounds of liquid oxygen from the external tank. The launch attempt January 7 scrubbed at T-9 minutes due to bad weather at both transoceanic abort landing sites (Moron, Spain and Dakar, Senegal). After a two-day delay, the launch set for January 9 was delayed due to the launch pad liquid oxygen sensor breaking off and lodging in the number two main engine prevalve. The launch set for January 10 was delayed two days due to heavy rains. The launch countdown on January 12 proceeded with no delays.

The planned landing at KSC, originally scheduled for January 17, moved to January 16 to save orbiter turnaround time. Landing attempts on January 16 and 17 were abandoned due to unacceptable weather at KSC. The landing set for January 18 at KSC but persisting bad weather forced a one revolution extension of mission and landing at Edwards.

Mission Highlights

The SATCOM KU-I (RCA Americom) satellite, attached to the Payload Assist Module-D2 (PAM-D2) motor, was deployed. Comet Halley Active Monitoring Program (CHAMP) experiment, a 35mm camera to photograph Comet Halley, did not function properly due to battery problems. Other payloads: Materials Science Laboratory-2 (MSL-2); Hitchhiker G-1; Infrared Imaging Experiment (IR-IE); Initial Blood Storage Experiment (IBSE); Hand-held Protein Crystal Growth (HPCG) experiment; three Shuttle Student Involvement Program (SSIP) experiments and 13 Get Away Specials (GAS), 12 of them mounted on a special GAS Bridge Assembly.

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The crew assigned to the STS-61C mission included (seated left to right) Charles F. Bolden, Jr., pilot; and Robert L. (Hoot) Gibson, commander. On the back row, left to right, are payload specialists Robert J. Cenker, and Congressman Bill Nelson. To the right of Nelson are mission specialists Steven A. Hawley, George D. Nelson, and Franklin R. Chang-Diaz. Launched aboard the Space Shuttle Columbia on January 12, 1986 at 6:55:00 am (EST), the STS-61C mission's primary payload was the communications satellite SATCOM KU-1 (RCA Americom).

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Piece of thermal insulation tile floats near the Shuttle Columbia

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Frams von STS-61C Columbia Mission NASA-Video:

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Quelle: NASA

 


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Sonntag, 15. Januar 2017 - 11:00 Uhr

Astronomie - ESO-Astronomiecamp 2016

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Das jüngste ESO-Astronomiecamp widmete sich dem Thema: Das sichtbare und verborgene Universum. Die ESO und ihr Science Outreach Network hat mit dem auf wissenschaftliche Fortbildung spezialisierten Organisator Sterrenlab und dem Astronomischen Observatorium der unabhängigen Region des Aostatals (OAVdA) zusammengearbeitet, um das vierte ESO-Astronomiecamp zum Thema des multispektralen Universums auszurichten. Das Camp fand vom 26. Dezember 2016 bis zum 1. Januar 2017 im italienischen Aostatal statt.

In dieser Woche nahmen die Teilnehmer – Jugendliche zwischen 16 und 18 aus verschiedenen ESO-Mitgliedsländern – an verschiedenen Vorträgen teil und führten praktische Aktivitäten aus, darunter auch nächtliche Beobachtungen mit den Teleskopen und Instrumenten des Observatoriums. Gruppenaktivitäten, Wintersport und Exkursionen trugen weiterhin dazu bei, das Camp für die Teilnehmer zu einer bleibenden Erinnerung werden zu lassen.

Einige Highlights des diesjährigen Programms waren: Die Benutzung eines Spektrografen, Vorträge von ESO-Astronomen und eine Exkursion zum Matterhorn.

Quelle: ESO

 

 


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Sonntag, 15. Januar 2017 - 10:30 Uhr

Raumfahrt - Die Tage der Iridium-Flare sind gezählt...

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Skywatchers: Get your Iridium flare fix now

 
File photo of an Iridium flare. Credit: Stephen Clark/Spaceflight Now

The launch of the first batch of new-generation Iridium communications satellites Saturday will mark the beginning of the end for the predictable, spectacular flares of reflected sunlight produced by the old-design craft, a favorite of amateur skywatchers for nearly two decades.

Iridium flares have dazzled in the evening and morning skies since the first satellites in the fleet launched in 1997.

Satellite passes are visible when an object flying overhead is still illuminated by the sun, and when the sun is below the horizon on the ground. Occasionally, a spacecraft will brighten when sunlight bounces off a reflective surface, like a solar array or antenna.

Unlike other objects in orbit around Earth, flares from Iridium’s Lockheed Martin-built relay craft are highly predictable — to the second — giving observers advance notice of when and where to look.

The first-generation Iridium satellites have three antenna panels mounted at an angle to the craft’s main body. Each one is highly reflective and treated with silver-coated Teflon.

When the sun strikes one of the antennas just right, a flare is visible from the ground. An observer positioned in the right place at the right time will see a sudden brightening of the satellite as it soars across the sky.

Image of a first-generation Iridium satellite. Credit: Smithsonian Air and Space Museum

The flares sometimes get as bright as -8 magnitude, brighter than the crescent moon, and last up to 20 seconds. The most brilliant flares can even be seen in daylight.

The long axis of the first-generation satellites always points directly to Earth at an altitude of 485 miles (780 kilometers). Savvy observers can calculate when the flares will occur and where to look by knowing the location of the spacecraft and the sun.

If math isn’t your thing, you can look up flares for your location at Heavens-Above.com by entering your observing site, and clicking on Iridium flares.

The flares are a design fluke, and Iridium’s new generation of communications satellites will not produce the phenomena.

There are normally 66 operational satellites in the Iridium fleet spread uniformly around the globe in six orbital lanes. The company’s satellites launched from 1997 through 2002, and were originally designed to function for just eight years.

Iridium says 64 members of the 66-satellite constellation are still active, relaying messages, voice calls and data around the world through inter-satellite links and ground stations for the company’s nearly 850,000 subscribers.

With an aging network, Iridium is about to launch the first batch of “Iridium Next” satellites as soon as Saturday to upgrade and replenish the fleet.

A SpaceX Falcon 9 rocket will carry 10 of the satellites, which use a single antenna and are of an entirely new design, into orbit from Vandenberg Air Force Base in California.

“Due to design improvements, our new satellites unfortunately are not expected to create flares, so enjoy Iridium flares while you can,” Iridium says on its website. “The new antennas offer increased data speed and capacity but are angled differently than the current design, and are therefore not likely to reflect much sunlight.”

The new satellites will replace the existing members of Iridium’s network one-by-one.

Once a fresh satellite is turned on and confirmed healthy, the old satellite will be removed from the fleet. In most cases, the retired craft will be de-orbited to burn up in Earth’s atmosphere, assuming it has enough leftover fuel for the maneuvers.

The $3 billion replacement program should be complete by mid-2018, when Iridium flares will be a thing of the past.

Quelle: SN


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Samstag, 14. Januar 2017 - 21:15 Uhr

Raumfahrt - Start von SpaceX-Falcon-9 mit 10 Iridium Communications Satelliten

3.01.2017

SpaceX plans Jan. 8 return to flight after completing failure investigation

WASHINGTON — SpaceX plans to resume Falcon 9 launches on Jan. 8 after completing the investigation into the pad explosion that destroyed another Falcon 9 four months ago.

In a statement posted on the SpaceX website Jan. 2, the company said the explosion was caused by the failure of one of three helium tanks, known as composite overwrapped pressure vessels (COPVs), inside the liquid oxygen tank in the rocket’s second stage. The company had previously indicated that a COPV failure was a leading cause of the accident.

Each COPV is made of an aluminum liner surrounded by a carbon composite overwrap. Other COPVs recovered from the Falcon 9 showed buckling of their liners, although what caused the buckling isn’t stated.

SpaceX said that the buckling, in and of itself, did not cause the tanks to fail. Instead, the company believes the buckles created voids between the liner and composite overwrap where liquid oxygen could pool. “When pressurized, oxygen pooled in this buckle can become trapped; in turn, breaking fibers or friction can ignite the oxygen in the overwrap, causing the COPV to fail,” the company said. The temperature of the helium in the COPV is also cold enough to freeze some of the oxygen, exacerbating the problem.

In its statement, SpaceX said that investigators did not find a single, most likely cause of the failure, but all the potential causes were similar. “The investigation team identified several credible causes for the COPV failure, all of which involve accumulation of super chilled [liquid oxygen] or [solid oxygen] in buckles under the overwrap,” the company stated.

SpaceX’s return-to-flight plans call for changes in procedures for fueling the rocket rather than design changes to the COPVs. According to the company, it will use warmer helium in the COPVs and also change the process for loading helium into those tanks “to a prior flight proven configuration based on operations used in over 700 successful COPV loads.”

The company didn’t state what effect these changes would have on launch preparations or vehicle performance. The current version of the Falcon 9 uses so-called “super-cooled” propellants, where liquid oxygen is chilled to near the freezing point to increase its density and improve the vehicle’s performance. Those propellants are loaded into the Falcon 9 shortly before launch.

Those procedural changes are intended only to be short-term solutions. “In the long term, SpaceX will implement design changes to the COPVs to prevent buckles altogether, which will allow for faster loading operations,” the company stated, but did not give a schedule for making those design changes.

The short-term fixes, though, should allow the Falcon 9 to resume launches that were put on hold after the Sept. 1 pad explosion. That includes the first of seven launches of Iridium Next satellites, which is now scheduled for no earlier than Jan. 8 from Vandenberg Air Force Base in California.

“Iridium is pleased with SpaceX’s announcement on the results of the Sept. 1 anomaly as identified by their accident investigation team, and their plans to target a return to flight on Jan. 8 with the first Iridium Next launch,” Iridium said in a Jan. 2 statement.

That schedule is pending the issuance of a launch license from the U.S. Federal Aviation Administration. The FAA has not granted that license yet, but sources say the FAA has received and is reviewing SpaceX’s report on the pad accident. In its statement, SpaceX noted that the FAA “provided oversight and coordination for the investigation” as part of the investigation team.

Should SpaceX successfully return to flight with the Iridium mission, its next launch is expected to be of the EchoStar-23 communications satellite later in January. That launch will be the first SpaceX mission from Launch Complex 39A at NASA’s Kennedy Space Center in Florida, a former space shuttle pad that SpaceX is leasing primarily for Falcon 9 launches of its Crew Dragon spacecraft and launches of its Falcon Heavy rocket. SpaceX will be using the pad for other Falcon 9 launches because of damage sustained at Space Launch Complex 40 in the September pad explosion.

Quelle: SN

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SpaceX targets Sunday return to flight from California

SpaceX is targeting a Sunday, Jan. 8, return to flight of its Falcon 9 rocket from California, where the company will adjust fueling procedures believed responsible for a Sept. 1 explosion that destroyed a rocket and satellite on their Cape Canaveral launch pad.

A four-month investigation pinpointed failures in the system that uses cold helium gas to pressurize propellant tanks filled with super-chilled liquid oxygen, SpaceX said.

Investigators found buckles had formed in the aluminum lining of helium tanks that are about as large as a person.

When the system was pressurized, the buckles trapped pools of liquid or solid oxygen between the linings and an outer layer of carbon wrap covering them. That build-up of oxygen likely created friction or caused carbon fibers to break, SpaceX said, which ignited the oxygen in the rocket’s upper stage during a countdown rehearsal at Cape Canaveral Air Force Station’s Launch Complex 40.

The Falcon 9 and Spacecom’s $200 million Amos-6 commercial communications satellite, which Facebook had hoped to use to extend Internet access in Africa, were lost, and the launch pad was severely damaged.

In an update posted online Monday morning, SpaceX, led by Elon Musk, said the helium tanks will be redesigned, but did not specify when that longer-term change would be implemented.

To prevent buckling in the short-term, the company said it would revert to “a prior flight proven configuration” for loading helium, including loading the gas at a warmer temperature. Those procedures have worked safely more than 700 times, SpaceX said, but take more time.

The planned Jan. 8 launch from Vandenberg Air Force Base will carry the first 10 of at least 70 communications satellites that SpaceX is contracted to launch for Iridium Communications.

As it did through much of the first half of last year, SpaceX plans to try to land the Falcon 9’s first stage on a modified barge in the ocean, continuing efforts to recover and re-launch Falcon boosters.

Before Sunday, SpaceX plans to fuel the Falcon 9 for a practice countdown like the one performed on Sept. 1, intended to end with a brief firing of the rocket's nine Merlin main engines. This time, no payload will be on top.

If the return to flight succeeds, a Falcon 9 could try to launch an unmanned Dragon cargo ship to the International Space Station from Kennedy Space Center before the end of the month.

The Sept. 1 explosion was the second time in 14 months that a Falcon 9 suffered a catastrophic failure. In June 2015, another breach in the upper-stage liquid oxygen tank doomed a Dragon mission to the ISS about two minutes into flight. SpaceX said that problem, attributed to a failed strut, was unrelated to the Sept. 1 explosion.

SpaceX led the recent investigation with oversight from the Federal Aviation Administration, which licenses commercial rocket launches. Other partners included NASA, the Air Force, the National Transportation Safety Board and several unidentified “industry experts.”

 

“SpaceX greatly appreciates the support of our customers and partners throughout this process, and we look forward to fulfilling our manifest in 2017 and beyond,” the company said in a statement.

Drawing from more than 3,000 channels of data from video and telemetry, the investigation focused on an instant — less than a tenth of a second — from the first sign of trouble to the rocket’s destruction.

For weeks after the accident, Musk did not rule out the possibility that someone might have fired a shot at the rocket.

NASA has been performing its own, independent investigation and has not yet released any findings.

The space agency relies upon SpaceX to deliver cargo to and from the space station, and also hopes to see the company launch astronauts to the outpost in early 2018.

SpaceX's late fueling of the Falcon 9 during the final half-hour of countdowns, when a crew would be sitting atop the rocket, has been a source of concern to NASA and some of its independent safety advisers.

Quelle: Florida Today

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SpaceX Closes AMOS-6 Investigation, Aims to Launch 10 Satellites Next Sunday

The first ten IridiumNEXT satellites are stacked and encapsulated in the Falcon 9 fairing for a Jan. 8 launch attempt from Vandenberg AFB, CA. Photo Credit: Iridium

The first ten IridiumNEXT satellites are stacked and encapsulated in the Falcon 9 fairing for a Jan. 8 launch attempt from Vandenberg AFB, CA. Photo Credit: Iridium

SpaceX is aiming to return their workhorse Falcon-9 rocket to flight next Sunday with a fleet of 10 Iridium NEXT satellites. The mission, currently scheduled to lift-off on Jan. 8 at 10:28 a.m. Pacific Time from Space Launch Complex 4E at Vandenberg Air Force Base, Calif., will mark SpaceX’s 30th Falcon-9 and the first launch for SpaceX since a Sept. 1 explosion took out their rocket, Cape Canaveral launch complex, and their customer’s AMOS-6 satellite.

The 10 satellites flying next weekend represent the first set of 70 total that Iridium is launching with SpaceX to replace their current constellation; all of which are contracted to fly on seven Falcon-9 launches over the next 18 months (prior to the AMOS-6 accident, Iridium wanted all their launches flown by the end of 2017).

The first ten IridiumNEXT satellites being stacked for flight atop a SpaceX Falcon 9 rocket for a Jan. 8 launch attempt at 10:28am Pacific time. Photo Credit: Iridium

The first ten IridiumNEXT satellites being stacked for flight atop a SpaceX Falcon 9 rocket for a Jan. 8 launch attempt at 10:28am Pacific time. Photo Credit: Iridium

A landing attempt of the Falcon-9 booster will occur far offshore minutes after launch, using the company’s autonomous “Just Read The Instructions” drone ship as a landing pad.

In the time since the Sep. 1 explosion, the accident investigation has focused heavily on a breach in the cryogenic helium system of the rocket’s second stage liquid oxygen tank, with special attention narrowed to one of the three composite over wrapped pressure vessels (COPVs) inside the LOX tank.

Having worked with numerous agencies, including NASA, the FAA, U.S. Air Force and NTSB, the Hawthorne, Calif.-based company today released final results of the investigation, as well as outlined some of the actions they intend to take moving forward to prevent another AMOS-6 incident from happening again.

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Over the past four months, officials at the Federal Aviation Administration (FAA), the U.S. Air Force (USAF), the National Aeronautics and Space Administration (NASA), the National Transportation Safety Board (NTSB), along with several industry experts, have collaborated with SpaceX on a rigorous investigation to determine the cause of the anomaly that occurred September 1 at Space Launch Complex 40 (SLC-40) at Cape Canaveral Air Force Station in Florida. This investigation team was established according to SpaceX’s accident investigation plan as approved by the FAA. As the primary federal licensing body, the FAA provided oversight and coordination for the investigation.

Investigators scoured more than 3,000 channels of video and telemetry data covering a very brief timeline of events – there were just 93 milliseconds from the first sign of anomalous data to the loss of the second stage, followed by loss of the vehicle. Because the failure occurred on the ground, investigators were also able to review umbilical data, ground-based video, and physical debris. To validate investigation analysis and findings, SpaceX conducted a wide range of tests at its facilities in Hawthorne, California and McGregor, Texas.

The accident investigation team worked systematically through an extensive fault tree analysis and concluded that one of the three composite overwrapped pressure vessels (COPVs) inside the second stage liquid oxygen (LOX) tank failed. Specifically, the investigation team concluded the failure was likely due to the accumulation of oxygen between the COPV liner and overwrap in a void or a buckle in the liner, leading to ignition and the subsequent failure of the COPV.

Each stage of Falcon 9 uses COPVs to store cold helium which is used to maintain tank pressure, and each COPV consists of an aluminum inner liner with a carbon overwrap. The recovered COPVs showed buckles in their liners. Although buckles were not shown to burst a COPV on their own, investigators concluded that super chilled LOX can pool in these buckles under the overwrap. When pressurized, oxygen pooled in this buckle can become trapped; in turn, breaking fibers or friction can ignite the oxygen in the overwrap, causing the COPV to fail. In addition, investigators determined that the loading temperature of the helium was cold enough to create solid oxygen (SOX), which exacerbates the possibility of oxygen becoming trapped as well as the likelihood of friction ignition.

Quelle: AS

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Update: 7.01.2017

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Foul Weather Pushes SpaceX’s Next Launch to Monday

SPACEX’S ARMY OF hopers and believers have been holding their breath in anticipation of its next launch. They’ll be blue in the face just a bit longer: The liftoff, which had been planned for this Sunday, January 8, has been pushed back a day due to foul weather.

The announcement, until now a rumor circulated in local Central California media, was made official today on the website of Iridium, SpaceX’s customer for the launch. This is SpaceX’s first launch since a Falcon 9 bearing a $200 million satellite blew up on September 1, 2016. This mission isn’t a redo of the Spacecom satellite that blew up, but the first in a series of seven for Iridium will launch a total of 70 miniature telecommunications satellites.

The launch, now scheduled for January 9, 10:22am PST, has been delayed because of foul weather. SpaceX’s west coast launch pad is located at Vandenberg Air Force base, in the mountainous shore north of the company’s Hawthorne, CA headquarters. Starting Saturday evening, Vandenberg, along with the rest of California, will get drenched by an invisible, incredibly moist tendril of air extending from the tropics. Meteorologists expect the so-called atmospheric river to drop upwards of a foot of rain on low-lying areas. Obviously, not the best conditions to launch a rocket.

Especially a rocket launch that every space junkie on the planet will be watching. Another failure would be very bad for SpaceX, because although the company still has a few years worth of launches on the books, it will have a hard time selling future customers on its safety record with a pair of back-to-back launchpad mishaps. And Musk would be selling his launches against the superior safety records of competitors like United Launch Alliance, Sierra Nevada, and Orbital ATK.

However, none of those other companies are landing their rockets, nor do they have any other clear path towards democratizing access to space. (Yeah, yeah, Blue Origin is landing rockets, but not rockets capable of taking big payloads into high orbits, like the Falcon 9 has done time and again.) Last year, the company landed four of its Cape Canaveral-launched Falcon 9 rockets on a droneship. And another two touched down on dry land. Re-launching Falcon 9s would save SpaceX tens of millions of dollars per launch.

Reusability, along with other pioneering budget-busters like highly compressed propellant, are what SpaceX was banking on in order to fulfill its promise of offering spaceflight to civilians. Elon Musk had been promising the first such re-launch would happen in late 2016. Now … well, let’s just get through Monday.

Or Tuesday, or Wednesday, or whenever California’s skies clear up enough for liftoff.

Quelle: WIRED

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Update: 8.01.2017

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SpaceX, Iridium Now Planning for Jan. 14 Falcon Rocket Blastoff at Vandenberg Air Force Base

West Coast's first launch of 2017 will mark debut for second-generation constellation of satellites for space-based communication system

A Falcon 9 rocket will carry 10 Iridium communications satellites into orbit, possibly as soon as Monday morning from Vandenberg Air Force Base.Click to view larger
A Falcon 9 rocket will carry 10 Iridium communications satellites into orbit, possibly as soon as Monday morning from Vandenberg Air Force Base. (Iridium Communications Inc. photo)
 

Despite having a Federal Aviation Administration license in hand and an on-pad test complete, a Falcon 9 rocket and its cargo still will have to wait several days longer for the launch  from Vandenberg Air Force Base.

Liftoff of the Space Exploration Technologies rocket now is planned for Jan. 14 from Space Launch Complex-4 on South Base, according to safety notices revised Saturday evening.

Reasons for the delay aren’t known, but weather-related postponements typically don’t occur more than 24 hours before liftoff. The team likely is battling other issues that can involve the technical troubles with a rocket, satellites or ground support equipment or even scheduling conflicts with other activities at Vandenberg.

 

Even if they are tackling technical troubles, the weather looked less than accommodating for a Monday launch attempt, however, as heavy rains are expected with an incoming winter storm.

Rainy conditions are expected for most of the week, with Saturday hinting at one of the best chances for sunshine, according to the National Weather Service.

"Can now confirm: new launch date Jan 14 at 9:54am pst. Bad weather the cause," Iridium CEO Matt Desch said on his Twitter account Sunday morning. "Anti-rain dances didn't work - oh well. Cal needs rain?" 

The team also has Jan. 15 reserved as a back-up date.

While many launches have longer windows that offer multiple chances to get off the ground, this mission has just one moment a day so the Iridium satellites can be placed in the proper place in space. The launch moves several minutes early for each day it delays.

Since late Friday, other signs hinted that a Monday attempt appeared shaky. Vandenberg officials did not release information about the upcoming launch as they typically do. 

As of Friday morning, Iridium officials were hopeful for a Monday attempt

“Looks like we’re good to go for Monday!” Desch said Friday on Twitter. “Payload/rocket mating underway; we’ll just have to see about the weather. Anti-rain dances, anyone?”

The Falcon will carry the first 10 Iridium NEXT satellites to begin building the second-generation constellation of craft for the space-based phone system.

“The finish line of the marathon is in sight,” said Scott Smith, Iridium chief operating officer. “The satellites are ready. The rocket is ready. Operations is ready. A new era is about to begin!”

On Friday, a day after the successful test of the rocket’s engines, the FAA Office of Commercial Space Transportation issued a license for the Falcon 9 rocket and six others for Iridium Communications.

“With completion of the static fire test, our first launch has just gotten that much closer,” Desch said.

“The Iridium team has been anxiously awaiting launch day, and we’re now all the more excited to send those first 10 Iridium Next satellites into orbit.”

The license came after the FAA accepted the investigation report on the dramatic Sept. 1 mishap in which a Falcon erupted into a fireball during an on-pad test in Florida.

In what is expected to be a first for the West Coast, SpaceX plans to possibly land the Falcon rocket’s first stage on a barge off the coast, according to the FAA license, which also mentions an ocean landing option.

SpaceX has conducted several flyback missions as part of Florida launches after the Falcon fulfilled the rocket’s primary mission.

Unlike landlines and cell phones, the Iridium system provides coverage over 100 percent of the earth’s surface, including across oceans, airways and polar regions, company representatives said.

The revolutionary system launched a majority of its original satellites plus several spares from Vandenberg aboard Delta II rockets between 1997 and 2002.

The campaign meant jobs for the launch crews plus full hotels and restaurants when support staff and visitors came to watch the blastoffs.

Other Iridium satellites headed to space aboard Chinese and Russian launchers.

The system is named for the 77th chemical element on the Periodic Table —marking the original number of craft planned for the constellation.

While design changes meant fewer satellites for the constellation, the moniker remained.

Falcon rocket launches from Vandenberg can be viewed from various viewing sites around the Lompoc Valley since the launch pad is visible south of West Ocean Avenue (Highway 246).

Quelle: Noozhawk

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Update: 9.01.2017

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SpaceX’s return to spaceflight pushed back to January 14th

 

The delay is due to high winds and rain near the launch site


1890 Views

Samstag, 14. Januar 2017 - 17:00 Uhr

Raumfahrt-History - 1985 Space-Shuttle STS-61B Atlantis Mission

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STS-61B
 
 

Mission: MORELOS-B; AUSSAT-2; SATCOM KU-2
Space Shuttle: Atlantis
Launch Pad: 39A 
Launch Weight: 261,455 pounds
Launched: November 26, 1985, 7:29:00 p.m. EST
Landing Site: Edwards Air Force Base, Calif.
Landing: December 3, 1985, 1:33:49 p.m. PST
Landing Weight: 205,732 pounds
Runway: 22 
Rollout Distance: 10,759 feet
Rollout Time: 78 seconds
Revolution: 109
Mission Duration: 6 days, 21 hours, 4 minutes, 49 seconds
Returned to KSC: December 7, 1985
Orbit Altitude: 225 nautical miles
Orbit Inclination: 57 degrees
Miles Traveled: 2.8 million 

Crew Members

                   STS-61B Crew Photo

Image above: STS-61B Crew photo with Commander Brewster H. Shaw, Jr., Pilot Bryan D. O'Connor, Mission Specialists Mary L. CleaveSherwood C. SpringJerry L. Ross and Payload Specialists Rodolfo Neri Vela and Charles D. Walker. Image Credit: NASA 

Mission Highlights

STS-61B Mission PatchThree communications satellites were deployed: MORE LOS-B (Mexico), AUSSAT-2 (Australia) and SATCOM KU-2 (RCA Americom). MORELOS-B and AUSSAT-2 were attached to the Payload Assist Module-D motors, SATCOM KU-2 to a PAM-D2 designed for heavier payloads. Two experiments were conducted to test assembling erectable structures in space: Experimental Assembly of Structures in Extravehicular Activity (EASE) and Assembly Concept for Construction of Erectable Space Structure (ACCESS). The experiments required two space walks by Spring and Ross lasting five hours, 32 minutes, and six hours, 38 minutes, respectively. Middeck payloads: Continuous Flow Electrophoresis System (CFES); Diffusive Mixing of Organic Solutions (DMOS); Morelos Payload Specialist Experiments (MPSE) and Orbiter Experiments (OEX). In payload bay: Get Away Special and IMAX Cargo Bay Camera (ICBC).

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Quelle: NASA

 


829 Views

Samstag, 14. Januar 2017 - 12:45 Uhr

Raumfahrt - ESA Astronauten Thomas Pesquet Proxima Mission-Update-2

29.12.2016

NASA Preps for Space Station Power Upgrade Spacewalks; Live NASA TV Coverage

Expedition 50 crew members Thomas Pesquet of ESA (European Space Agency) and Peggy Whitson and Shane Kimbrough of NASA
Expedition 50 crew members Thomas Pesquet of ESA (European Space Agency) and Peggy Whitson and Shane Kimbrough of NASA capture a quick selfie during robotics training inside the Cupola of the International Space Station.
Credits: NASA

Expedition 50 astronauts will venture outside the International Space Station at 7 a.m. EST Jan. 6 and 13 to perform a complex upgrade to the orbital outpost’s power system. Coverage of the spacewalks will begin at 5:30 a.m. on NASA Television and the agency’s website.

 

On Wednesday, Jan. 4, NASA TV will air a briefing at 2 p.m. from the agency’s Johnson Space Center in Houston to preview the spacewalk activities. The briefing participants are:

  • Kenneth Todd, International Space Station Operations Integration Manager
  • Jud Frieling, flight director for Jan. 6 spacewalk
  • Gary Horlacher, flight director for Jan. 13 spacewalk
  • Troy McCracken, lead battery replacement robotics officer
  • Kieth Johnson, lead spacewalk officer

 

Media may attend the briefing at Johnson or ask questions by calling the Johnson newsroom at 281-483-5111 no later than 1:45 p.m. Jan. 4.

 

Working on the right side truss of the space station, the crew members will install adapter plates and hook up electrical connections for six new lithium-ion batteries that were delivered to the station in December.

 

Expedition 50 Commander Shane Kimbrough and Flight Engineer Peggy Whitson of NASA will perform the first spacewalk Jan. 6. The work will continue Jan. 13 during the second spacewalk, which will be conducted by Kimbrough and Flight Engineer Thomas Pesquet of ESA (European Space Agency).

 

Prior to each spacewalk, the new batteries will be robotically extracted from a pallet to replace 12 older nickel-hydrogen batteries through a series of robotic operations. Nine of the older batteries will be stowed in a cargo resupply craft for later disposal, while three will remain on the station’s truss, disconnected from the power grid. The robotic operations will not air on NASA TV.

 

This will be the 196th and 197th spacewalks in support of space station assembly and maintenance. Kimbrough will be designated extravehicular crew member 1 (EV 1), wearing the suit bearing red stripes for both spacewalks, the third and fourth of his career.

 

Whitson will be making the seventh spacewalk of her career and match the record of NASA’s Suni Williams, for most spacewalks by a woman. She will be designated extravehicular crew member 2 (EV 2), wearing the suit with no stripes for the first spacewalk.

 

Pesquet, who will be making the first spacewalk of his career, will be extravehicular crew member 2 for the second spacewalk, also wearing a suit with no stripes.

Quelle: NASA

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Update: 8.01.2017

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Ever looked straight into a volcano… from space? 's Mauna-Loa volcano with snow on top & lava flow patterns on its slopes.

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Update: 9.01.2016

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The Rocky mountains are a step too high – even for the clouds to cross

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Update: 12.01.2017

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Expedition 50 Astronauten Shane Kimbrough und Thomas Pesquet sind bereit für den zweiten Spacewalk ihrer Mission

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Astronaut Thomas Pesquet (center) assists spacewalkers Peggy Whitson (left) and Shane Kimbrough in the U.S. Quest airlock on Jan. 6, 2017.

Expedition 50 astronauts Shane Kimbrough and Thomas Pesquet are ready for their mission’s second spacewalk that starts Friday at 7 a.m. EST. The duo will wrap up power maintenance work to connect new lithium-ion batteries and install adapter plates. Kimbrough and NASA astronaut Peggy Whitson started that work last Friday during a six-hour, 32-minute spacewalk.

Both spacewalks complement the ongoing robotics work that started at the end of December. Ground controllers have been remotely-operating the Canadarm2 robotic arm and Dextre robotic hand to remove and stow the old nickel-hydrogen batteries and the install the new batteries.

The three cosmonauts have been staying focused on their set of Russian space research and lab maintenance. Station veterans Andrey Borisenko and Oleg Novitskiy collected blood samples for a pair human research studies looking at bone loss and stress responses caused by living in space. First-time station resident Sergy Ryzhikov explored chemical reactions caused by jet engine exhaust in the Earth’s upper atmosphere.

Quelle: NASA

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Update: 13.01.2017

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Quelle: NASA

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Update: 14.01.2017

The requisite space selfie! Nice reflection of Earth in the helmet. Unbelievable feeling to be your own space vehicle…

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Quelle: ESA

 

 

 

 

 


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Samstag, 14. Januar 2017 - 10:45 Uhr

Raumfahrt - Sicherheits-Panel hat Bedenken für Crew an Bord vor SpaceX Betankung Prozess

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Safety panel cites concerns over SpaceX fueling process for commercial crew

 

WASHINGTON — A NASA safety board recommended in its annual report that the agency closely study the safety issues associated with SpaceX’s fueling plans for Falcon 9 commercial crew missions.

The annual report by the Aerospace Safety Advisory Panel (ASAP), released Jan. 11, raised the issue of what it calls the “load and go” approach planned by SpaceX to fuel the Falcon 9 rocket with liquid oxygen and kerosene propellants only after astronauts have boarded the Dragon spacecraft.

Traditionally, launch vehicles are fueled hours before launch, and only afterwards do crews board the spacecraft. However, SpaceX has shifted to an approach of fueling the rocket starting only about a half-hour before launch. That allows the company to use “super-cooled” liquid oxygen, which is denser and provides additional performance. However, it would require crews to board the Dragon prior to the start of fueling.

ASAP, in its report, noted that it is not clear how safe this approach is given the limited experience of the “load and go” approach. “In this regard, the Panel is concerned that the dynamic thermal effects on the system associated with loading densified propellants may not be adequately understood, which results in a higher level of uncertainty that must be factored into the risk determination,” it stated.

Another NASA advisory group, the International Space Station Advisory Committee, first raised concerns about the “load and go” approach in a December 2015 letter to NASA. The issue received new scrutiny when a Falcon 9 rocket exploded on the pad prior to a static-fire test Sept. 1 in advance of the scheduled launch of the Amos-6 communications satellite. 

“There is a unanimous, and strong, feeling by the committee that scheduling the crew to be on board the Dragon spacecraft prior to loading oxidizer into the rocket is contrary to booster safety criteria that has been in place for over 50 years, both in this country and internationally,” Stafford wrote in the letter, which NASA released in November.

Stafford raised the issue again at an Oct. 31 meeting of this committee, when he complained that NASA had not responded to his original letter, even after the pad accident. The agency, in a later statement, said it was still evaluating NASA’s plans for fueling the Falcon 9 for commercial crew launches, and would incorporate the results of the pad explosion investigation into that analysis.

SpaceX announced Jan. 2 that it had completed the investigation into the explosion. It blamed the accident on buckling of the aluminum liner of a composite overwrapped pressure vessel used to store helium in the rocket’s upper stage liquid oxygen tank. Liquid oxygen pooled in the gap between the liner and the carbon overwrap, leading to friction and the subsequent failure of the pressure vessel. The Federal Aviation Administration, which licenses Falcon 9 commercial launches, said Jan. 6 it had accepted the results of that investigation and issued a launch license for SpaceX’s next Falcon 9 launch of 10 Iridium satellites, now scheduled for Jan. 14.

ASAP, in its report, said it was concerned that there may be additional, unforeseen issues associated with the “load and go” fueling process. “Despite testing at the component and subassembly level, systems often display ‘emergent’ behavior once they are used in the actual operational environment,” the panel stated in the report. It called for NASA to better understand “how the system functions in the dynamic thermal environment associated with ‘load and go’ so that other previously unidentified hazards can be discovered.”

Some former NASA astronauts remain skeptical of SpaceX’s fueling approach. “I am not a supporter of ‘load and go’! ‘Steep hill’ for SpaceX to convince NASA of load and go’s safety for crew,” tweeted former astronaut Mike Foreman, a veteran of two shuttle missions, in response to the report Jan. 12.

“You are not alone,” Clayton Anderson, another former astronaut, tweeted in response.

ASAP cited the “load and go” fueling approach by SpaceX, as well as a fault tolerance issue on the Centaur upper stage that will be used to launch Boeing’s CST-100 commercial crew vehicle, as issues for NASA to watch for in the commercial crew program. That is complicated, the panel said, by the fact that the companies control the design of their commercial crew systems, with NASA providing oversight.

“In this type of environment, the [NASA commercial crew program] must work diligently to ensure that acceptable risk is not defined by ‘the best we can do given the constraints,’” the panel’s report stated. “The residual risk must be openly acknowledged and elevated to the appropriate level within the Agency for consideration.”

Quelle: SN


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Samstag, 14. Januar 2017 - 10:00 Uhr

Astronomie - Cygnus A Galaxie glänzt in Funkfrequenzen, die von relativistischen Elektronen kommen

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Astronomers have discovered an object in the active galaxy Cygnus A that wasn’t there before.

Cygnus A in radio

The galaxy Cygnus A "shines" in radio frequencies (seen here), coming from relativistic electrons zipping along jets shot out from the central black hole and deposited in giant "radio lobes." (The lobes extend outward roughly 10 times farther than the galaxy itself, which is invisible in this image.) 
NRAO / AUI

Last week at the American Astronomical Society meeting in Grapevine, Texas, astronomers made an announcement that’s caught the interest of several researchers: a very bright something has appeared in a well-known galaxy.

That galaxy is the elliptical Cygnus A. Cygnus A is one of the brightest radio sources in the sky. It lies approximately 800 million light-years from us (redshift of 0.056). In its core sits a supermassive black hole madly eating and cocooned in gas, while two jets shoot out to either side and light up the intergalactic medium. This activity produces the radio radiation that makes Cygnus A so bright.

Using the recently upgraded Karl G. Jansky Very Large Array (VLA) in New Mexico, Rick Perley (NRAO) and colleagues took a gander at Cygnus A — the first time the instrument has looked at the galaxy since 1989. (Apparently astronomers spent so much VLA time observing the galaxy in the 1980s that they didn’t feel the need to look again, Perley joked January 6th in his AAS presentation.) The new observations showed a surprise: a new, secondary object just southwest of the central black hole. This object wasn’t in the 1989 radio image. Additional, higher-resolution observations with the Very Long Baseline Array also picked up the object, clearly distinct from the galaxy’s nucleus. It’s roughly 1,300 light-years from the center.

The whatever-it-is is about twice as bright as the brightest known supernova at these frequencies. In fact, it’s much brighter than just about any transitory radio signal known, except for accreting supermassive black holes and tidal disruption events, outbursts created when a black hole eats a star.

The team scoured other archives and found the object in 2003 Keck infrared observations and, more iffily, in some images from Hubble. (The object is so red that it doesn’t show up well at optical wavelengths, and in this range the space telescope’s resolution isn’t as good as that of Keck’s adaptive optics.)

Cygnus A in infrared

This false-color infrared image from the Keck II telescope shows the galaxy Cygnus A. Its central supermassive black hole is the large red-black splotch, but this 2003 image reveals a second, mystery source (circled) nearby.
G. Canalizo et al. / Astrophysical Journal 2003

The science session’s attendees were aflutter with curiosity. Claire Max, who serves as director of the University of California Observatories (which manages both the Keck and Lick Observatories), went back and dug through Keck data and discovered that, in fact, astronomers had already discovered this source. In 2003 she, Gabriela Canalizo (now at University of California, Riverside), and colleagues had stumbled upon the mystery source. They, too, had gone back and found it in some Hubble images and not others — they weren’t sure whether that was because the source was flickering, or just that Hubble hadn’t looked long enough to consistently see it.

The team determined that the whatchamacallit wasn’t a foreground object in the Milky Way, nor a cluster of young stars in Cygnus A. Rather, it seemed to be a compact cluster of old, red stars, with all the trappings of being the stripped-down core of a much smaller galaxy that Cygnus A had eaten. That minor merger might also explain why the big galaxy’s black hole has “turned on,” the astronomers suggested in their 2003 Astrophysical Journal paper.

On the other hand, Canalizo and colleagues went on to suggest in 2004 that the source might instead be a peek at the hot inner rim of the dusty doughnut enshrouding the black hole.

Perley’s team favors a merger, too. But he advocated instead that the radiation might come from a second black hole, the leftover core of the eaten galaxy. If so, then Cygnus A is one of a few galaxies that seems to host a central binary black hole.

At the end of his presentation Perley called for others to look through their archival observations so that astronomers can pinpoint when this source appeared. His team is also looking in X-ray, but given that the central nucleus is so bright, they’re not optimistic of their chances of seeing something, unless there’s some variability. A formal paper and press release (with cool images!) are in the works, and when they’re out we’ll update you with more info.

Quelle: Sky&Telescope


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