samedi 3 août 2013

Launch of H-II Transfer Vehicle "KOUNOTORI4" (HTV4) by H-IIB Launch Vehicle No. 4












JAXA - H-II Transfer Vehicle "KOUNOTORI4" (HTV4) patch.

August 3, 2013

video
 A new visitor launches for the International Space Station

Mitsubishi Heavy Industries, Ltd. and the Japan Aerospace Exploration Agency launched the H-IIB Launch Vehicle No.4 (H-IIB F4) with the KOUNOTORI4 (HTV4, a cargo transfer vehicle to the International Space Station) onboard at 4:48:46 a.m. on August 4 (Sun.) 2013 (Japan Standard Time, JST) from the Tanegashima Space Center.

The launch vehicle flew smoothly, and, at about 14 minutes and 59 seconds after liftoff, the separation of the KOUNOTORI4 was confirmed.

Separation of the HTV. Image credit: JAXA

We would like to express our profound appreciation for the cooperation and support of all related personnel and organizations that helped contribute to the successful launch of the H-IIB F4.

HTV cutaway and description. Image credit: JAXA

At the time of the launch, the weather was fine, a wind speed was 3.5 meters/second from the northwest and the temperature was 27.9 degrees Celsius.

H-IIB Launch Vehicle No.4 (H-IIB F4) Launch Sequence (Quick Review)


(*1) The values are based on quick report results without detailed data evaluation.
(*2) The values are updated ones based on actual measurement data such as thrust characteristics which are unique for the H-IIB F4 engines. Therefore, they are slightly different from the values in the Launch Plan.
(*3) When the combustion chamber presser becomes 10% against the largest combustion pressure.
(*4) The definition of SRB-A jettison is to cut the thrust struts.
(*5) When the launch vehicle sent the separation signal

Mission website:

H-IIB Launch Vehicle: http://www.jaxa.jp/projects/rockets/h2b/index_e.html

H-II Transfer Vehicle "KOUNOTORI" (HTV): http://www.jaxa.jp/projects/rockets/htv/index_e.html

Images, Video, Text, Credits: Japan Aerospace Exploration Agency (JAXA) / Mitsubishi Heavy Industries, Ltd. / NASA / NASA TV.

Greetings, Orbiter.ch

Hubble Finds Telltale Fireball After Gamma Ray Burst











NASA - Hubble Space Telescope patch.

Aug. 3, 2013

 Gamma-ray Burst 130603B

NASA's Hubble Space Telescope recently provided the strongest evidence yet that short-duration gamma ray bursts are produced by the merger of two small, super-dense stellar objects.

The evidence is in the detection of a new kind of stellar blast called a kilonova, which results from the energy released when a pair of compact objects crash together. Hubble observed the fading fireball from a kilonova last month, following a short gamma ray burst (GRB) in a galaxy almost 4 billion light-years from Earth. A kilonova had been predicted to accompany a short-duration GRB, but had not been seen before.

GRB 130603B Host and Surrounding Field

"This observation finally solves the mystery of the origin of short gamma ray bursts," said Nial Tanvir of the University of Leicester in the United Kingdom. Tanvir lead a team of researchers using Hubble to study the recent short-duration GRB. "Many astronomers, including our group, have already provided a great deal of evidence that long-duration gamma ray bursts (those lasting more than two seconds) are produced by the collapse of extremely massive stars. But we only had weak circumstantial evidence that short bursts were produced by the merger of compact objects. This result now appears to provide definitive proof supporting that scenario."

The team's results appear Saturday, Aug., 3 in a special online edition of the journal Nature.

GRB 130603B — June 13, 2013

A kilonova is about 1,000 times brighter than a nova, which is caused by the eruption of a white dwarf.  The self-detonation of a massive star, a supernova, can be as much as 100 times brighter than a kilonova. Gamma ray bursts are mysterious flashes of intense high-energy radiation that appear from random directions in space. Short-duration blasts last at most a few seconds, but they sometimes produce faint afterglows in visible and near-infrared light that continue for several hours or days. The afterglows have helped astronomers determine that GRBs lie in distant galaxies.

GRB 130603B — July 3, 2013

Astrophysicists have predicted short-duration GRBs are created when a pair of super-dense neutron stars in a binary system spiral together. This event happens as the system emits gravitational radiation, creating tiny waves in the fabric of space-time. The energy dissipated by the waves causes the two stars to sweep closer together. In the final milliseconds before the explosion, the two stars merge into a death spiral that kicks out highly radioactive material. This material heats up and expands, emitting a burst of light.

Stellar Merger Model for Gamma-ray Burst

Illustration above: This sequence illustrates a model for the formation of a short-duration gamma-ray burst.

1. A pair of neutron stars in a binary system spiral together. Orbital momentum is dissipated through the release of gravity waves, which are tiny ripples in the fabric of space-time.

2. In the final milliseconds, as the two objects merge, they kick out highly radioactive material. This material heats up and expands, emitting a burst of light called a kilonova. An accompanying gamma-ray burst lasts just one-tenth of a second, but is 100 billion times brighter than the kilonova flash.

3. The fading fireball blocks visible light but radiates in infrared light.

4. A remnant disk of debris surrounds the merged object, which may have collapsed to form a black hole.

In a recent science paper Jennifer Barnes and Daniel Kasen of the University of California at Berkeley and the Lawrence Berkeley National Laboratory presented new calculations predicting how kilonovas should look. They predicted the same hot plasma producing the radiation also will block the visible light, causing the gusher of energy from the kilonova to flood out in near-infrared light over several days.

Compass and Scale Image for GRB 130603B

An unexpected opportunity to test this model came June 3 when NASA' s Swift space telescope picked up the extremely bright gamma ray burst, cataloged as GRB 130603B. Although the initial blast of gamma rays lasted just one-tenth of a second, it was roughly 100 billion times brighter than the subsequent kilonova flash.

From June 12-13, Hubble searched the location of the initial burst, spotting a faint red object. An independent analysis of the data from another research team confirmed the detection. Subsequent Hubble observations on July 3 revealed the source had faded away, therefore providing the key evidence the infrared glow was from an explosion accompanying the merger of two objects.

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

For images and more information on the kilonova, visit: http://hubblesite.org/news/2013/29

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

Images Text, Credits: NASA, ESA, N. Tanvir (University of Leicester), A. Fruchter and A. Field (STScI), and A. Levan (University of Warwick).

Best regards, Orbiter.ch

vendredi 2 août 2013

40 Years Ago, Skylab Paved Way for International Space Station












NASA - Skylab Mission patch.

Aug. 2, 2013


Image above: As the crew of Skylab 2 departs, the gold sun shield covers the main portion of the space station. The solar array at the top was the one freed during a spacewalk. The four, windmill-like solar arrays are attached to the Apollo Telescope Mount used for solar astronomy. Image Credit: NASA.

The International Space Station has been in operation with research ongoing since Nov. 2, 2000. America's first space station, Skylab, helped pave the way for permanent operations in low-Earth orbit 40 years ago this year.

Skylab was hailed as a "bold concept" by Rocco Petrone, who served as director of launch operations at NASA's Kennedy Space Center in Florida before becoming director of the agency's Marshall Space Flight Center in Huntsville, Ala., during 1973 and 1974.

"The program demanded innovation and ingenuity," said Petrone in Skylab, Our First Space Station, a NASA report published in 1977. "Experience and knowledge gained from earlier space programs provided a solid foundation on which to build, but the Skylab Program was truly making new pathways in the sky."


Image above: The Skylab space station is mated to a Saturn V rocket in the Vehicle Assembly Building on Sept. 29, 1972. Image Credit:
NASA.

The project began as the Apollo Applications Program in 1968 with an objective to develop science-based human space missions using hardware originally developed for the effort to land astronauts on the moon.

Skylab orbited the Earth from 1973 to 1979. The 169,950-pound space station included a workshop, a solar observatory, a multiple docking adapter and systems to allow three crews to spend up to 84 days in space. While the space station lifted off unpiloted as Skylab 1 atop a Saturn V launch vehicle, the astronaut crews were launched to orbit by Saturn 1B rockets.

Liftoff of Skylab 1 came on May 14, 1973, but within minutes it was apparent that there was trouble. NASA's Skylab Program Manager William Schneider, filled in the details at a post-launch news conference.

"At approximately 63 seconds into the launch of Skylab 1, there was an indication of premature deployment of the meteoroid protective shield," Schneider said. "If that has happened, the shield was probably torn off. The thermal indications are that it is gone, and we have some indication that our solar array on the workshop also did not fully deploy."


Image above: Prior to launch in May 1973, the Skylab space station, foreground, awaits liftoff atop a Saturn V on the Kennedy Space Center's Launch Pad 39A. To the north, is the Saturn 1B with an Apollo command-service module being prepared to launch the first crew to Skylab. Image Credit: NASA.

As a result of the uncertainty, launch of Skylab 2 with the crew of Charles Conrad, Joseph Kerwin and Paul Weitz, scheduled for the next day, was postponed.

The NASA-industry team around the country went into action to develop plans and hardware necessary to save Skylab. The astronauts practiced using special tools to remove material that jammed the remaining solar array to allow it to provide Skylab with the needed electrical power. A square thermal shield, which operated like a sunshade, also was developed to protect the station from the heat of the sun.

The crew launched May 25, 1973 aboard an Apollo command-service module and mission commander Conrad expressed confidence that their preparations would pay off right away.

"This is Skylab 2, we fix anything," he said at the moment of liftoff.


Image above: The Skylab 1-Saturn V space vehicle is lifts off from Launch Pad 39A on May 14, 1973. Image Credit: NASA.

The crew deployed the new solar shield through a small scientific experiment airlock, located in the side of the workshop normally facing the sun. Once outside, the shield popped open like a parasol, with four struts extending outward from a segmented center post. Temperatures inside the lab soon diminished to near-normal levels.

Next came the spacewalk to free the jammed solar away. After considerable work, Kerwin was able to cut the metal that had jammed the solar wing in a folded position. Using a rope sling, Conrad forced the array beam to deploy. Full extension of the solar panel occurred later, providing electrical power crucial for the three planned piloted missions.


Image above: During a spacewalk on June 7, 1973, astronaut Joseph Kerwin uses a cutting instrument to remove metal which had jammed the solar array in a partially opened position. The successful effort by Kerwin and Charles Conrad allowed the solar panels to fully deploy and provide the needed electricity for the three Skylab expeditions. Image Credit: NASA.

With the Skylab 2 mission back on track, the crew focused on the primary goals of the program -- studies in materials processing in microgravity, Earth observations, expanding knowledge of solar astronomy, and proving that humans could live and work in space for extended periods.

The longest American spaceflight at that point was the 14-day mission of Gemini 7 astronauts Frank Borman and James Lovell. Skylab 2 would double that record and show that the astronauts adapted well.


Image above: Skylab 3 science astronaut Owen Garriott operates the Apollo Telescope Mount from a console in the Skylab space station. Observations of the sun were a primary achievement of the program. Image Credit: NASA.

"Mobility around here is super," Conrad said. "Every kid in the United States would have a blast up here."

Following splashdown in the Pacific Ocean and recovery of Skylab 2 on June 22, 1973, NASA Administrator James Fletcher had high praise for the crew and the entire agency-industry team.

"For the first time, a crew of astronauts has returned from an extended tour in a space laboratory," he said. "Essentially all of the objectives for this mission have been completed."

Skylab 3 launched the second crew on July 28, 1973, with Alan Bean, Owen Garriott and Jack Lousma aboard.

Early in the mission, Garriott and Lousma performed a spacewalk to erect a new twin-pole solar shield that provided better thermal control for the remainder of the Skylab missions.


Image above: Skylab 4 commander Gerald Carr flies the astronaut maneuvering equipment experiment in the forward compartment of the Skylab space station. The jet-propelled back pack was designed to demonstrate the unit's flying qualities. The effort helped pave the way for use of the Manned Maneuvering Unit that aided spacewalkers during the space shuttle program. Image Credit: NASA.

The second crew returned to Earth Sept. 25, 1973, following 59 days in orbit.

Skylab 4 originally was planned for a mission of about the same length. When the final Skylab expedition was extended to 80 days or more, NASA's Preflight Operations Branch at Kennedy, under Raul "Ernie" Reyes, was given the challenge to squeeze another 980 pounds of food, film and equipment into the Apollo command module. Using Reyes' "a place for everything, and everything in its place" philosophy, his team succeeded in using every cubic inch of storage space.

On Nov. 16, 1973, astronauts Gerald Carr, Edward Gibson and William Pogue lifted off. During their 84-day mission, the Skylab 4 crew continued the comprehensive research programs.

All three expeditions produced a vast study of the Earth -- its crops, weather and changes in environment. They also completed a revealing study of the sun, while crews manufactured alloys, grew perfect crystals and learned to work in space.

Following splashdown and recovery on Feb. 8, 1974, Fletcher stressed the importance of Skylab's accomplishments for the future of human spaceflight.

"It has moved the space program from the realm of the spectacular, into a new phase that can be characterized possibly as almost businesslike," he said. "It has contributed to an orderly transition from the Apollo era to the space shuttle."

Skylab 3 pilot Jack Lousma recently noted that the program helped pave the way for long-duration missions in low-Earth orbit as well as to Mars and beyond.

"Flights of 28, 59 and 84 days were forerunners of what we are doing now aboard the International Space Station," he said. "The fact that we could work in space for longer periods is one of the things we were able to prove during Skylab."

Images (mentioned), Text, Credit: NASA / Bob Granath.

Cheers, Orbiter.ch

NASA's Curiosity Nearing First Anniversary on Mars












NASA - Mars Science Laboratory (MSL) patch.

Aug. 2, 2013

Curiosity Sol 343 Vista With 'Twin Cairns' on Route to Mount Sharp (click on the image for enlarge)

Image above: This scene combines seven images from the telephoto-lens camera on the right side of the Mast Camera (Mastcam) instrument on NASA's Mars rover Curiosity. Image Credit:
NASA/JPL-Caltech/Malin Space Science Systems.

NASA's Curiosity rover will mark one year on Mars next week and has already achieved its main science goal of revealing ancient Mars could have supported life. The mobile laboratory also is guiding designs for future planetary missions.

"Successes of our Curiosity -- that dramatic touchdown a year ago and the science findings since then -- advance us toward further exploration, including sending humans to an asteroid and Mars," said NASA Administrator Charles Bolden. "Wheel tracks now, will lead to boot prints later."

After inspiring millions of people worldwide with its successful landing in a crater on the Red Planet on Aug. 5, 2012, PDT (Aug. 6, 2012, EDT), Curiosity has provided more than 190 gigabits of data; returned more than 36,700 full images and 35,000 thumbnail images; fired more than 75,000 laser shots to investigate the composition of targets; collected and analyzed sample material from two rocks; and driven more than one mile (1.6 kilometers).

Westward View from Curiosity on Sol 347

Image above: NASA's Mars rover Curiosity used the Navigation Camera (Navcam) on its mast to record this westward look on the 347th Martian day, or sol, of the rover's work on Mars (July 28, 2013). Image Credit: NASA/JPL-Caltech.

Curiosity team members at NASA's Jet Propulsion Laboratory in Pasadena, Calif.,will share remembrances about the dramatic landing night and the overall mission in an event that will air on NASA Television and the agency’s website from 7:45 to 9 a.m. PDT (10:45 a.m. to noon EDT) on Tuesday, Aug. 6. Immediately following that program, from 9 a.m. to 10:30 a.m. (noon to 1:30 p.m.), NASA TV will carry a live public event from NASA Headquarters in Washington. That event will feature NASA officials and crew members aboard the International Space Station as they observe the rover anniversary and discuss how its activities and other robotic projects are helping prepare for a human mission to Mars and an asteroid. Social media followers may submit questions on Twitter and Google+ in advance and during the event using the hashtag #askNASA.

Curiosity, which is the size of a car, traveled 764 yards (699 meters) in the past four weeks since leaving a group of science targets where it worked for more than six months. The rover is making its way to the base of Mount Sharp, where it will investigate lower layers of a mountain that rises three miles from the floor of the crater.


NASA's Mars Science Laboratory spacecraft and its unprecedented sky crane landing system placed Curiosity on Mars near the base of Mount Sharp. The mountain has exposed geological layers, including ones identified by Mars orbiters as originating in a wet environment. The rover landed about one mile (1.6 kilometers) from the center of that carefully chosen, 12-mile-long (20-kilometer-long) target area.

Scientists decided first to investigate closer outcrops where the mission quickly found signs of vigorous ancient stream flow. These were the first streambed pebble deposits ever examined up close on Mars.

Evidence of a past environment well suited to support microbial life came within the first eight months of the 23-month primary mission from analysis of the first sample material ever collected by drilling into a rock on Mars.

"We now know Mars offered favorable conditions for microbial life billions of years ago," said the mission's project scientist, John Grotzinger of the California Institute of Technology in Pasadena. "It has been gratifying to succeed, but that has also whetted our appetites to learn more. We hope those enticing layers at Mount Sharp will preserve a broad diversity of other environmental conditions that could have affected habitability."

video
Curiosity Rover: One Year on Mars

The mission measured natural radiation levels on the trip to Mars and is monitoring radiation and weather on the surface of Mars, which will be helpful for designing future human missions to the planet. The Curiosity mission also found evidence Mars lost most of its original atmosphere through processes that occurred at the top of the atmosphere. NASA's next mission to Mars, Mars Atmosphere and Volatile Evolution (MAVEN), is being prepared for launch in November to study those processes in the upper atmosphere.

Full Curiosity Traverse Passes One-Mile Mark 


The total distance driven by NASA's Mars rover Curiosity passed the one-mile mark a few days before the first anniversary of the rover's landing on Mars.

This map traces where Curiosity drove between landing at "Bradbury Landing" on Aug. 5, 2012, PDT, (Aug. 6, 2012 (Universal Time and EDT) and the position reached during the mission's 351st Martian day, or sol, (Aug. 1, 2013).  The Sol 351 leg added 279 feet (85.1 meters) and brought the odometry since landing to about 1.05 miles (1,686 meters).

The mapped area is within Gale Crater and north of the mountain called Mount Sharp in the middle of the crater. After the first use of the drill, the rover's main science destination will be on the lower reaches of Mount Sharp. For broader-context images of the area, see http://photojournal.jpl.nasa.gov/catalog/PIA16064 and http://photojournal.jpl.nasa.gov/catalog/PIA16058.

The base image from the map is from the High Resolution Imaging Science Experiment Camera (HiRISE) in NASA's Mars Reconnaissance Orbiter. Image credit: NASA/JPL-Caltech/Univ. of Arizona.

JPL, a division of the California Institute of Technology, Pasadena, manages the Curiosity mission and built the rover for NASA's Science Mission Directorate in Washington.

To follow the conversation online about Curiosity's first year on Mars, use hashtag #1YearOnMars or follow @NASA and @MarsCuriosity on Twitter.

For NASA TV streaming video, schedule and downlink information, visit http://www.nasa.gov/ntv . The events airing on Tuesday also will be carried on Ustream at http://www.ustream.tv/nasajpl .

A movie made with Hazard-Avoidance Camera images from Curiosity's first year, titled "Twelve Months in Two Minutes," is available at http://mars.nasa.gov/msl/1yearin2mins .

For more information about the mission, visit http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl .

Images (mentioned), Video (mentioned), Text, Credits: NASA / Dwayne Brown / JPL / Guy Webster.

Greetings, Orbiter.ch

jeudi 1 août 2013

Monster Galaxies Lose Their Appetite With Age









NASA - WISE Mission logo / NASA - Spitzer Space Telescope logo.

Aug. 1, 2013


Image above: This image shows two of the galaxy clusters observed by NASA's Wide-field Infrared Survey Explorer (WISE) and Spitzer Space Telescope missions. Image Credit: NASA/JPL-Caltech/SDSS/NOAO.

Our universe is filled with gobs of galaxies, bound together by gravity into larger families called clusters. Lying at the heart of most clusters is a monster galaxy thought to grow in size by merging with neighboring galaxies, a process astronomers call galactic cannibalism.

New research from NASA's Spitzer Space Telescope and Wide-field Infrared Survey Explorer (WISE) is showing that, contrary to previous theories, these gargantuan galaxies appear to slow their growth over time, feeding less and less off neighboring galaxies.

"We’ve found that these massive galaxies may have started a diet in the last 5 billion years, and therefore have not gained much weight lately," said Yen-Ting Lin of the Academia Sinica in Taipei, Taiwan, lead author of a study published in the Astrophysical Journal.

Peter Eisenhardt, a co-author from NASA's Jet Propulsion Laboratory in Pasadena, Calif., said, "WISE and Spitzer are letting us see that there is a lot we do understand -- but also a lot we don’t understand -- about the mass of the most massive galaxies." Eisenhardt identified the sample of galaxy clusters studied by Spitzer, and is the project scientist for WISE.

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

The new findings will help researchers understand how galaxy clusters -- among the most massive structures in our universe -- form and evolve.

Galaxy clusters are made up of thousands of galaxies, gathered around their biggest member, what astronomers call the brightest cluster galaxy, or BCG. BCGs can be up to dozens of times the mass of galaxies like our own Milky Way. They plump up in size by cannibalizing other galaxies, as well as assimilating stars that are funneled into the middle of a growing cluster.

To monitor how this process works, the astronomers surveyed nearly 300 galaxy clusters spanning 9 billion years of cosmic time. The farthest cluster dates back to a time when the universe was 4.3 billion years old, and the closest, when the universe was much older, 13 billion years old (our universe is presently 13.8 billion years old).

"You can't watch a galaxy grow, so we took a population census," said Lin. "Our new approach allows us to connect the average properties of clusters we observe in the relatively recent past with ones we observe further back in the history of the universe."

Spitzer and WISE are both infrared telescopes, but they have unique characteristics that complement each other in studies like these. For instance, Spitzer can see more detail than WISE, which enables it to capture the farthest clusters best. On the other hand, WISE, an infrared all-sky survey, is better at capturing images of nearby clusters, thanks to its larger field of view. Spitzer is still up and observing; WISE went into hibernation in 2011 after successfully scanning the sky twice.

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

The findings showed that BCG growth proceeded along rates predicted by theories until 5 billion years ago, or a time when the universe was about 8 billion years old. After that time, it appears the galaxies, for the most part, stopped munching on other galaxies around them.

The scientists are uncertain about the cause of BCGs' diminished appetites, but the results suggest current models need tinkering.

"BCGs are a bit like blue whales -- both are gigantic and very rare in number. Our census of the population of BCGs is in a way similar to measuring how the whales gain their weight as they age. In our case, the whales aren't gaining as much weight as we thought. Our theories aren't matching what we observed, leading us to new questions," said Lin.

Another possible explanation is that the surveys are missing large numbers of stars in the more mature clusters. Clusters can be violent environments, where stars are stripped from colliding galaxies and flung into space. If the recent observations are not detecting those stars, it's possible that the enormous galaxies are, in fact, continuing to bulk up.

Future studies from Lin and others should reveal more about the feeding habits of one of nature's largest galactic species.

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

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

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

Best regards, Orbiter.ch

When galaxies switch off












ESA - Hubble Space Telescope logo.

1 August 2013

Hubble's COSMOS survey solves "quenched" galaxy mystery

Sample of non-star-forming galaxies from the COSMOS survey

Some galaxies hit a point in their lives when their star formation is snuffed out, and they become "quenched". Quenched galaxies in the distant past appear to be much smaller than the quenched galaxies in the Universe today. This has always puzzled astronomers — how can these galaxies grow if they are no longer forming stars? A team of astronomers has now used a huge set of Hubble observations to give a surprisingly simple answer to this long-standing cosmic riddle.

Until now, these small, snuffed-out galaxies were thought to grow into the larger quenched galaxies we see nearby.

As these galaxies are no longer forming new stars, they were thought to grow by colliding and merging with other smaller quenched galaxies some five to ten times less massive. However, these mergers would require many such small galaxies floating around for the quenched population to snack on — which we do not see.

The full COSMOS field (UltraVISTA)

Until recently it had not been possible to explore a sufficient number of quenched galaxies, but now a team of astronomers has used observations from the Hubble COSMOS survey to identify and count these switched-off galaxies throughout the last eight billion years of cosmic history.

"The apparent puffing up of quenched galaxies has been one of the biggest puzzles about galaxy evolution for many years," says Marcella Carollo of ETH Zurich, Switzerland, lead author on a new paper exploring these galaxies. "No single collection of images has been large enough to enable us to study very large numbers of galaxies in exactly the same way — until Hubble's COSMOS," adds co-author Nick Scoville of Caltech, USA.

The team used the large set of COSMOS images [1], alongside additional observations from the Canada–France–Hawaii Telescope and the Subaru Telescope, both in Hawaii, USA, to peer back to when the Universe was less than half its present age. These observations mapped an area in the sky almost nine times that of the full Moon.

The field around the COSMOS survey (ground-based image)

The quenched galaxies seen at these times are small and compact — and surprisingly, it seems they stay that way. Rather than puffing up and growing via mergers over time, these small galaxies mostly keep the size they had when their star formation switched off [2]. So why do we see these galaxies apparently growing larger over time?

"We found that a large number of the bigger galaxies instead switch off at later times, joining their smaller quenched siblings and giving the mistaken impression of individual galaxy growth over time," says co-author Simon Lilly, also of ETH Zurich. "It's like saying that the increase in the average apartment size in a city is not due to the addition of new rooms to old buildings, but rather to the construction of new, larger apartments," adds co-author Alvio Renzini of INAF Padua Observatory, Italy.

video
Zoom on the COSMOS field (UltraVISTA)

This tells us a lot about how galaxies have evolved over the last eight billion years of the Universe's history. It was already known that actively star-forming galaxies were smaller in the early Universe, explaining why they were smaller when their star formation first switched off.

"COSMOS provided us with simply the best set of observations for this sort of work — it lets us study very large numbers of galaxies in exactly the same way, which hasn't been possible before," adds co-author Peter Capak, also of Caltech. "Our study offers a surprisingly simple and obvious explanation to this puzzle. Whenever we see simplicity in nature amidst apparent complexity, it's very satisfying," concludes Carollo.

Notes:

[1] In making the COSMOS survey, Hubble photographed 575 slightly overlapping views of the Universe using the Advanced Camera for Surveys (ACS) aboard Hubble. It took nearly 1000 hours of observations and is the largest project ever conducted with Hubble. This survey has proved invaluable; it has helped to map dark matter in 3D (heic0701), to further understand the effects of gravitational lensing (heic0806), and to characterise the expansion of the Universe (heic1005).

[2] There is still the possibility of growth via mergers for a fraction of this quenched population, but not a majority, as previously thought.
Notes for editors

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

The research is presented in a paper entitled “Newly-quenched galaxies as the cause for the apparent evolution in average size of the population”, for publication in The Astrophysical Journal.

[1] The international team of astronomers in this study consists of C. M. Carollo (Swiss Federal Institute of Technology [ETH Zurich], Switzerland), T. J. Bschorr (Swiss Federal Institute of Technology [ETH Zurich], Switzerland), A. Renzini (Padova Observatory, Italy), S. J. Lilly (Swiss Federal Institute of Technology [ETH Zurich], Switzerland), P. Capak (Spitzer Science Center, California Institute of Technology, USA), A. Cibinel (Swiss Federal Institute of Technology [ETH Zurich], Switzerland), O. Ilbert (Laboratoire d’Astrophysique de Marseille, France), M. Onodera (Swiss Federal Institute of Technology [ETH Zurich], Switzerland), N. Scoville (California Institute of Technology, USA), E. Cameron (Swiss Federal Institute of Technology [ETH Zurich], Switzerland), B. Mobasher (University of California, USA), D. Sanders (University of Hawaii, USA), Y. Taniguchi (Ehime University, Japan).

Links:

Research paper: http://www.spacetelescope.org/static/archives/releases/science_papers/heic1313a.pdf

The COSMOS survey: http://cosmos.astro.caltech.edu/

Images of Hubble: http://www.spacetelescope.org/images/archive/category/spacecraft/

Images credits: NASA / ESA / M. Carollo (ETH Zurich) / ESO/ UltraVISTA team / Acknowledgement: TERAPIX / CNRS / INSU / CASU / ESA/ Hubble & Digitized Sky Survey 2. Acknowledgment: Davide De Martin (ESA / Hubble) / Video: ESO / A. Fujii/Digitized Sky Survey 2 / UltraVISTA team ESO. Music: John Dyson (from the album Moonwind).

Greetings, Orbiter.ch

Action-Packed Time For Albert Einstein ATV












ESA - Albert Einstein ATV-4 mission patch.

1 August 2013

Albert Einstein, ESA’s unmanned cargo ferry at the International Space Station, will start pumping propellants today into the orbital outpost. This will be followed by air and oxygen transfers before it resumes boosting the Station’s orbit.

ATV-4 docked to Zvezda

ATV-4 is the fourth Automated Transfer Vehicle to serve the Station; it was launched on 5 June and reached the complex nine days later. Since then, this European cargo carrier has been firmly attached to the Station, acting as an additional module.

All 2489 kg of dry cargo has now been carried into the Station and the crew has already loaded 1213 kg of waste into ATV. Around two more tonnes of unused equipment, rubbish and other material will be packed into the vehicle before it completes its mission in spectacular fashion as a cosmic rubbish removal van in late October, burning up safely as it reenters the atmosphere.

Normal mission
So far, ATV’s mission has been quiet, as everything goes according to plan. “We like having this kind of mission,” says Jean-Michel Bois, Head of the ESA Operations Team at the ATV Control Centre in Toulouse, France.

“Of course, there have been small issues – there always are – but they keep us on our toes. Everything is in a great state and ATV is working beautifully.”

Working inside ATV

The 60-strong team from ESA, France’s CNES space agency and industry at the control centre constantly monitor ATV’s health and they are always ready for unscheduled actions, like avoiding orbital debris by changing the Station’s orbit with ATV’s powerful engines. Albert Einstein has already preformed a major planned reboost, using 200 kg of propellant and raising the Station’s orbit by about 10 km.

The only significant unplanned event came last week, when one of ATV’s three computers was automatically shut down by onboard software. Then a second computer failed on Sunday – not a problem as ATV can operate fine with just one unit.

Even so, critical activities require all computers to be working normally so some of the Toulouse centre’s key personnel cut their holidays short to tackle the problem.

With this additional help, the two computers were soon restarted. ATV was then ready to go ahead with preparations for the propellant transfer.

Refuelling and refreshing the Station

The fuel pipes were pressurised on 31 July, leaving ATV ready to pump 860 kg of fuel and oxidiser into the tanks of Zarya module on Thursday afternoon. All of the available propellants will be transferred during the 1.5-hour operation, after which the pipes will be purged and evacuated to avoid any problems when ATV undocks.

Keeping an eye on ATV

Then air and oxygen will flow into the Station on 12 and 13 August. ATV-4 holds 66.3 kg of air and 33.3 kg of pure oxygen for the crew. It also arrived with 564 kg of water in its tanks, 23% of which has already been pumped into the Station’s tanks.

On 14 August, ATV will light up its engines for another orbit reboost, followed by another on 28 August.

According to planning, ATV will undock and head for the fiery end to its mission on 28 October.

Related links:

Automated Transfer Vehicle: http://www.esa.int/Our_Activities/Human_Spaceflight/ATV

ATV blog: http://blogs.esa.int/atv

Ariane 5: http://www.esa.int/Our_Activities/Launchers/Launch_vehicles/Ariane_5

Images, Text, Credits: ESA / NASA.

Cheers, Orbiter.ch

Water in a martian desert












ESA - Mars Express Mission patch.

1 August 2013

 Searching for water near Tagus Valles

Craters once brim-full with sediments and water have long since drained dry, but traces of their former lives as muddy lakes cling on in the martian desert.

The images were taken on 15 January by ESA’s Mars Express, and feature a region just a few degrees south of the equator within the ancient southern highlands of Mars. The unnamed region lies immediately to the north of an ancient riverbed known as Tagus Valles and east of Tinto Valles and Palos crater that were presented in an earlier release.(http://www.esa.int/Our_Activities/Space_Science/At_the_mouth_of_the_red_valley)

The 34 km-wide crater in the top left of the main images perhaps draws most attention with its chaotic interior. Here, broad flat-topped blocks called mesas can be found alongside smaller parallel wind-blown features known as yardangs.

Tagus Valles in context

Both mesas and yardangs were carved from sediments that originally filled the crater, deposited there during a flood event that covered the entire scene. Over time, the weakest sediments were eroded away, leaving the haphazard pattern of stronger blocks behind.

Further evidence of this crater’s watery past can be seen in the top right of the crater in the shape of a small, winding river channel.

Colour-coded topography of Tagus Valles region

Clues also hang onto the ghostly outline of an ancient crater some 20 km to the east (below in the main images). While the crater has all but been erased from the geological record, a long meandering channel clearly remains, and flows towards the crater in the centre of the scene.

This central complex of craters is seen close up in the perspective view below, showing in more detail another channel-like feature, along with a highly deformed crater. Perhaps the rim of this eroded crater was breached as sediments flooded the larger crater.

Deformation in a flooded crater

The crater is also seen from a different angle and in the background of the second perspective view below. In the foreground is one of the deepest craters in the scene, as indicated by the topography map.

Numerous landslides have occurred within this crater, perhaps facilitated by the presence of water weakening the crater walls. Grooves etched into the crater’s inner walls mark the paths of tumbling rocks, while larger piles of material have slumped en-masse to litter the crater floor.

Landslides inside a crater

A group of interconnected craters with flat floors smoothed over by sediments lie in the lower right part of the main image. One small crater with a prominent debris deposit – an ejecta blanket – lies within the crater.

Ejecta blankets are composed of material excavated from inside the crater during its formation. This particular crater exhibits a ‘rampart’ ejecta blanket – one with petal-like lobes around its edges. Liquid water bound up in the ejected material allowed it to flow along the surface, giving it a fluid appearance.

Tagus Valles region in 3D

But it’s not just water that has played a role in this region; volcanic eruptions have also had their say. A dark layer of fine-grained ash covers the top left corner of the main image that may have been deposited from the Elysium volcanic province to the northeast. Over time, the ash was redistributed by wind, and buried deposits exposed in localised areas by erosion.

This region is one of many that exposes evidence of the Red Planet’s active past, and shows that the marks of water are engraved in even the most unlikely ancient crater-strewn fields.

Related links:

Looking at Mars: http://www.esa.int/Our_Activities/Space_Science/Mars_Express

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

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

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

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

Mars Express blog: http://blogs.esa.int/mex/

Mars Webcam: http://blogs.esa.int/vmc

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

Best regards, Orbiter.ch

Elliptical Crater on Mercury












NASA - MESSENGER Mission to Mercury patch.

August 1, 2013


This color image, taken on May 1, 2013 by the Wide Angle Camera (WAC) instrument aboard NASA's MESSENGER spacecraft orbiting Mercury, features Hovnatanian crater, named for Armenian painter Hakop Hovnatanian. The crater's elliptical shape and the bright rays' butterfly pattern indicate that a very oblique impact produced the crater. The brightness of the rays indicate that they are relatively young features on Mercury's surface.

This image was acquired as a targeted high-resolution 11-color image set. Acquiring 11-color targets is a new campaign that began in March, 2013 and that utilizes all of the camera's 11 narrow-band color filters. Because of the large data volume involved, only features of special scientific interest are targeted for imaging in all 11 colors.

The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the solar system's innermost planet. MESSENGER has acquired over 150,000 images and extensive other data sets, and is capable of continuing orbital operations until early 2015.

For more information about MESSENGER mission, visit: http://www.nasa.gov/mission_pages/messenger/main/index.html

Image Credit: NASA / Johns Hopkins University Applied Physics Laboratory / Carnegie Institution of Washington.

Greetings, Orbiter.ch

mercredi 31 juillet 2013

ALICE through a gamma-ray looking glass












CERN - European Organization for Nuclear Research logo.

July 31, 2013

The ALICE experiment at CERN specializes in heavy-ion collisions at the LHC, which can produce thousands of particles. In analysing this maelstrom, the researchers need to know exactly how material is distributed in the detector - and it turns out that the LHC's simpler proton–proton collisions can help.

A gamma-ray view of the layers of the ALICE detector. (Image: ALICE)

Gamma-rays produced in the proton–proton collisions, mainly from the decays of neutral pions, convert into pairs of electrons and positrons as they fly through matter in the detector.  The origin of these pairs can be accurately detected, providing a precise 3D image that includes even the inaccessible innermost parts of the experiment. The process is almost exactly the same as in 1895 when Wilhelm Röntgen produced an X-ray image of his wife’s hand – the inner parts of the body could be seen for the first time without surgery. The main difference lies in the energy of the radiation – ten times greater for the gamma rays in ALICE than for Röntgen’s X-rays. Importantly for the ALICE experiment, it allows the team to check crucial simulations.

Read more: "ALICE through a gamma-ray looking glass" – CERN Courier: http://cerncourier.com/cws/article/cern/54018

Note:

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

For more information about European Organization for Nuclear Research (CERN), visit: http://home.web.cern.ch/

Image (mentioned), Text, Credits: CERN / Christine Sutton.

Greetings, Orbiter.ch

Cassini Spacecraft Reveals Forces Controlling Saturn Moon Jets












NASA / ESA - Cassini Mission to Saturn patch.

July 31, 2013


Image above: This set of images from NASA's Cassini mission shows how the gravitational pull of Saturn affects the amount of spray coming from jets at the active moon Enceladus. Image Credit: NASA/JPL-Caltech/University of Arizona/Cornell/SSI.

The intensity of the jets of water ice and organic particles that shoot out from Saturn's moon Enceladus depends on the moon's proximity to the ringed planet, according to data obtained by NASA's Cassini spacecraft.

The finding adds to evidence that a liquid water reservoir or ocean lurks under the icy surface of the moon. This is the first clear observation the bright plume emanating from Enceladus' south pole varies predictably. The findings are detailed in a scientific paper in this week's edition of Nature.


Image above: This set of images from NASA's Cassini mission shows the difference in the amount of spray emanating from Saturn's moon Enceladus. Image Credit: Image Credit: NASA/JPL-Caltech/University of Arizona/Cornell.

"The jets of Enceladus apparently work like adjustable garden hose nozzles," said Matt Hedman, the paper's lead author and a Cassini team scientist based at Cornell University in Ithaca, N.Y. "The nozzles are almost closed when Enceladus is closer to Saturn and are most open when the moon is farthest away. We think this has to do with how Saturn squeezes and releases the moon with its gravity."

Cassini, which has been orbiting Saturn since 2004, discovered the jets that form the plume in 2005. The water ice and organic particles spray out from several narrow fissures nicknamed "tiger stripes."

"The way the jets react so responsively to changing stresses on Enceladus suggests they have their origins in a large body of liquid water," said Christophe Sotin, a co-author and Cassini team member at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Liquid water was key to the development of life on Earth, so these discoveries whet the appetite to know whether life exists everywhere water is present."


Image above: Cassini imaging scientists used views like this one to help them identify the source locations for individual jets spurting ice particles, water vapor and trace organic compounds from the surface of Saturn's moon Enceladus. Image Credit: Image Credit: NASA/JPL/Space Science Institute.

For years scientists hypothesized the intensity of the jets likely varied over time, but no one had been able to show they changed in a recognizable pattern. Hedman and colleagues were able to see the changes by examining infrared data of the plume as a whole, obtained by Cassini's visual and infrared mapping spectrometer (VIMS), and looking at data gathered over a long period of time.

The VIMS instrument, which enables the analysis of a wide range of data including the hydrocarbon composition of the surface of another Saturnian moon, Titan, and the seismological signs of Saturn's vibrations in its rings, collected more than 200 images of the Enceladus plume from 2005 to 2012.

These data show the plume was dimmest when the moon was at the closest point in its orbit to Saturn. The plume gradually brightened until Enceladus was at the most distant point, where it was three to four times brighter than the dimmest detection. This is comparable to moving from a dim hallway into a brightly lit office.


Image above: Dramatic plumes, both large and small, spray water ice out from many locations along the famed "tiger stripes" near the south pole of Saturn's moon Enceladus. Image Credit: Image Credit: NASA/JPL/Space Science Institute.

Adding the brightness data to previous models of how Saturn squeezes Enceladus, the scientists deduced the stronger gravitational squeeze near the planet reduces the opening of the tiger stripes and the amount of material spraying out. They think the relaxing of Saturn's gravity farther away from planet allows the tiger stripes to be more open and for the spray to escape in larger quantities.

"Cassini's time at Saturn has shown us how active and kaleidoscopic this planet, its rings and its moons are," said Linda Spilker, Cassini project scientist at JPL. "We've come a long way from the placid-looking Saturn that Galileo first spied through his telescope. We hope to learn more about the forces at work here as a microcosm for how our solar system formed."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology, Pasadena, manages the mission for NASA's Science Mission Directorate in Washington. The VIMS team is based at the University of Arizona in Tucson.

For more information about the Cassini mission, visit:  http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov and http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens

Images (mentioned), Text, Credits: NASA / Dwayne Brown / JPL / Jia-Rui C. Cook.

Cheers, Orbiter.ch