European Space Agency : ESA ground team in simulation training for GOCE launch

ESA mission controllers in simulation training for GOCE launch

The Mission Control Team at ESA's Space Operations Centre (ESOC) are now in intense training for the scheduled 10 September launch of GOCE, the Agency's Gravity field and steady-state Ocean Circulation Explorer.

GOCE is scheduled for lift-off at 16:21 CEST, 10 September 2008, from the Plesetsk Cosmodrome; the spacecraft arrived in Russia on 29 July on board an Antonov-124 cargo aircraft.

On 14 August, members of the Mission Control Team were on console in the Main Control Room at ESOC, Darmstadt, Germany, for a
12-hour simulation of the mission's countdown and launch phases; the simulation included practicing immediate reactions in case of any unexpected problems with the ground segment or the spacecraft.

	Keeping watch over system status during the GOCE launch simulation.

GOCE team supported by experts throughout ESOC

The overall Mission Control Team is led by Flight Operations Director Pier Paolo Emanuelli and comprises a dedicated
13-person Flight Control Team, joined by an extended team of engineers from Ground Operations, Flight Dynamics, Software Support, Computers & Network Support, and ground stations.

Additional expertise is provided from ESOC in the areas of training, documentation and facilities management.


GOCE will orbit at an exceptionally low altitude

"The GOCE mission team are receiving excellent support from our colleagues at ESOC. GOCE is a challenging mission and will orbit at an exceptionally low altitude of just 268 km, so spacecraft control is very critical. The simulations campaign is close to the end and we are fully ready to support the launch in September," said Emanuelli.

	The 14 August simulation included both the A and B sections of the GOCE Flight Control Team

To achieve its mission objectives - mapping Earth's gravity field in unprecedented detail - the slender, 5m-long satellite is designed to orbit at a low altitude because the gravitational variations are stronger closer to Earth.

The GOCE team will undergo intensive training, simulations and work-ups between now and the launch, with a strong focus on practicing for LEOP - the Launch and Early Orbit phase - the crucial first steps in GOCE's mission beginning after the satellite separates from the launcher's upper-most stage.

One highlight of today's training will be establishing and testing the voice and data communication links between ESOC in Germany and the Launch Control Centre at Plesetsk, Russia.

	The 13-person GOCE flight control team is supported by many specialists throughout ESOC.

The GOCE team conducted previous simulations in July and August, and have spent the past months defining and confirming procedures and plans covering all possible nominal and contingency situations.

Flight control team engineers have also been working intently to ensure that the ground segment - the computers and software here at ESOC - is ready to support the mission.

A full launch and LEOP rehearsal will be conducted on 5 September, just five days prior to launch.

Today's 12-hour simulation practised the countdown and launch phases of the GOCE mission.

American Psychological Association : Psychologists show new ways to deal with health challenges in space

Psychologists reveal groundbreaking research, technology that will help address psychosocial challenges in next 'Age of Exploration'

BOSTON—As NASA prepares to send humans back to the moon and then on to Mars, psychologists are exploring the challenges astronauts will face on missions that will be much longer and more demanding than previous space flights. Psychologists outlined these mental health challenges Thursday at the American Psychological Association's 116th Annual Convention, and introduced a new interactive computer program that will help address psychosocial challenges in space.

"Lessons learned from the past, research in extreme environments, training, conditioning, and countermeasures for psychological stress are some of the things NASA is in the process of addressing for the upcoming age of exploration," said psychologist Marc Shepanek, PhD, from the Office of the Chief Health and Medical Officer at NASA.

Psychologists said longer missions mean astronauts will be faced with immense psychological pressures as they adjust to being so far away from Earth, which could lead to depression and interpersonal conflicts. The presenters spoke at APA's first symposium to address the psychological challenges of returning to the moon and going to Mars.

Historically, astronauts have been reluctant to admit to mental or behavioral health problems for fear of being grounded. Psychologist James Carter, PhD, and his colleagues are in the process of developing a suite of interactive computer programs, dubbed the Virtual Space Station, using input from 13 veteran long-duration NASA astronauts who have flown on the International Space Station, Mir and Skylab. The system is being evaluated in a set of randomized controlled clinical trials. This interactive program will help astronauts prevent, detect, assess and manage their own psychosocial problems. They will learn how to cope with depression and how to resolve conflicts with other astronauts.

"Behavioral health problems can interfere with the success of the mission, especially on long-duration space flights like missions to the International Space Station, the moon and Mars. These self-guided software tools will provide private and immediate access to treatments even though the patient may be many miles from Earth," Carter said in prepared remarks. The Virtual Space Station has already been deployed in Antarctica.

However, as astronauts aim to explore a new planet, the one they leave behind could be foremost on their minds. They will have limited contact with their families and radio communications with Mission Control will be delayed, possibly for as long as 40 minutes. In her presentation, family sociologist Phyllis Johnson, PhD, analyzed interviews with astronauts who had spent an extended amount of time in space. The astronauts identified what they felt was the role of NASA, themselves and their families in creating a "home away from home" during their flights. "For example, they emphasized the importance of regular communication regarding work, publicity and education, all of which provide connection to Earth and helped to reduce the perception of isolation," said Johnson.

Psychologists also looked to history for guidance in future space missions. "The closest analogue to Mars exploration is the exploration of Earth," said psychologist Peter Suedfeld, PhD. "Both maritime and terrestrial explorers struck off into the unknown, often for many years at a time." Like space explorers, they had little or no communication with home, and had to devise ways of coping with unforeseen and unfamiliar hardships and dangers. Psychologists are re-examining sea and land voyagers' diaries, logs and letters for a glimpse into how these explorers dealt with boredom, rebelliousness and dissent. They said it may be best way to predict some aspects of future long-duration missions.

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Presentations: "Preparing for the Psychological Stress of Long-duration Space Missions," Marc A. Shepanek, PhD, Office of the Chief Health and Medical Officer, NASA; "Living in Space: Creating a Home Away From Home," Phyllis J. Johnson, PhD, University of British Columbia; "The Uses of History: Space Analogues Revisited," Peter Suedfeld, PhD, University of British Columbia; "Computer-based Psychosocial Support for Long-duration Spaceflights," James A. Carter, PhD, Harvard Medical School, Leonard Greenhalgh, PhD, Amos Tuck School of Business at Dartmouth College, Steven E. Locke, MD, Harvard Medical School, Jay C. Buckey, MD, Dartmouth Medical School, Mark T. Hegel, PhD, Dartmouth Medical School; Session 1111 – Symposium: To the Moon and Mars: Psychology of Long-Duration Space Exploration, 10:00 – 11:50 AM, Thursday, Aug. 14, Boston Convention and Exhibition Center, Meeting Level 2, Meeting Room 206A. Symposium Chair: Douglas A. Vakoch, PhD, SETI Institute. Discussants: Edna R. Fiedler, PhD, National Space Biomedical Research Institute, Uwe P. Gielen, PhD, St. Francis College, Walter Sipes, PhD, NASA/Johnson Space Center

Full texts of the remarks are available from the APA Public Affairs Office.

For more information/interview, please contact: Douglas Vakoch at (510) 688-0028 or by e-mail at vakoch@seti.org.

The symposium presenters can also be contacted:

Marc Shepanek, PhD – NASA Office of the Chief Health and Medical Officer; "Preparing for the Psychological Stress of Long-Duration Space Missions"; phones: (W) 202-358-2201, (C) 202-744-7541, (H) 202-244-2787; mshepanek@hq.nasa.gov

Phyllis Johnson, PhD – Univ. of British Columbia, Vancouver, Canada; "Living in Space: Creating a Home Away From Home"; phones: (W) 604-822-4300, (H) 604-687-8886, (Boston) 617-227-8600; pjohnson@interchange.ubc.ca

Peter Suedfeld, PhD – University of British Columbia, Vancouver, Canada; "Uses of History: Space Analogues Revisited"; phones: (W) 604-822-5713, (Boston) 617-227-8600; psuedfeld@psych.ubc.ca

James Carter, PhD – Harvard Medical School; "Computer-Based Psychosocial Support for Long-Duration Spaceflights"; phones (W) 617-667-1507, (C) 617-851-8913; jacarter@caregroup.harvard.edu

The American Psychological Association (APA), in Washington, DC, is the largest scientific and professional organization representing psychology in the United States and is the world's largest association of psychologists. APA's membership includes more than 148,000 researchers, educators, clinicians, consultants and students. Through its divisions in 54 subfields of psychology and affiliations with 60 state, territorial and Canadian provincial associations, APA works to advance psychology as a science, as a profession and as a means of promoting human welfare.

NASA/Goddard Space Flight Center : NASA data show some African drought linked to warmer Indian Ocean

A new study, co-funded by NASA, has identified a link between a warming Indian Ocean and less rainfall in eastern and southern Africa. Computer models and observations show a decline in rainfall, with implications for the region's food security.

Rainfall in eastern Africa during the rainy season, which runs from March through May, has declined about 15 percent since the 1980s, according to records from ground stations and satellites. Statistical analyses show that this decline is due to irregularities in the transport of moisture between the ocean and land, brought about by rising Indian Ocean temperatures, according to research published today in Proceedings of the National Academy of Sciences. This interdisciplinary study was organized to support U.S. Agency for International Development's Famine Early Warning Systems Network.

"The last 10 to 15 years have seen particularly dangerous declines in rainfall in sensitive ecosystems in East Africa, such as Somalia and eastern Ethiopia," said Molly Brown of NASA's Goddard Space Flight Center, Greenbelt, Md., a co-author of the study. "We wanted to know if the trend would continue or if it would start getting wetter."

To find out, the team analyzed historical seasonal rainfall data over the Indian Ocean and the eastern seaboard of Africa from 1950 to 2005. The NASA Global Precipitation Climatology Project's rainfall dataset provided a series of data covering both the land and the oceans. They found that declines in rainfall in Ethiopia, Kenya, Tanzania, Zambia, Malawi and Zimbabwe were linked to increases in rainfall over the ocean.

The team used computer models that describe the atmosphere and historical climate data to identify and validate the source of this link. Lead author Chris Funk of the University of California, Santa Barbara, and colleagues showed that the movement of moisture onshore was disrupted by increased rainfall over the ocean.

Funk and colleagues used a computer model from the National Center for Atmospheric Research to confirm their findings. The combination of evidence from models and historical data strongly suggest that human-caused warming of the Indian Ocean leads to an increase of rainfall over the ocean, which in turn adds energy to the atmosphere. Models showed that indeed, the added energy could create a weather pattern that reduces the flow of moisture onshore and bring dry air down over the African continent, reducing rainfall.

Next, the team investigated whether or not the decline in rainfall over eastern Africa would continue. Under guidance from researchers at USGS, which co-funded the study, the team looked at 11 climate models to simulate rainfall changes in the future. Ten of the 11 models agreed that though 2050, rainfall over the Indian Ocean would continue to increase – depriving Africa's eastern seaboard of rainfall.

"We can be quite certain that the decline in rainfall has been substantial and will continue to be," Funk said. "This 15 percent decrease every 20-25 years is likely to continue."

The trend toward dryer rainy seasons in eastern and southern Africa directly impacts agricultural productivity. To evaluate how potential future rainfall scenarios and shifts in agriculture could affect undernourishment, the team came up with a "food-balance indicator" model. The model considers factors such as growing-season rainfall, fertilizer, seed use, crop area and population to estimate the number of undernourished people a region can anticipate.

Continuing along a "business as usual" scenario – with current trends in declining rainfall and agricultural capacity continuing as it is currently to 2030, the team found that the number of undernourished people will increase by more than 50 percent in eastern Africa.

Still, the food-balance indicator also showed that in the face of a continuation of the current downward trend in rainfall, even modest increases in agricultural capacity could reduce the number of undernourished people by 40 percent.

"A strong commitment to agricultural development by both African nations and the international community could lead fairly quickly to a more food-secure Africa," Funk said.

ESA/Hubble Information Centre : Globular clusters tell tale of star formation in nearby galaxy metropolis

The NASA/ESA Hubble Space Telescope has identified thousands of more than 5 billion year-old globular clusters in the Virgo cluster of galaxies. One of the results of these discoveries led astronomers to understand more about the life and evolution of cannibal galaxies. Globular star clusters, dense bunches of hundreds of thousands of stars, contain some of the oldest surviving stars in the Universe. A new international study of globular clusters outside our Milky Way Galaxy has found evidence that these hardy pioneers are more likely to form in dense areas, where star birth occurs at a rapid rate, instead of uniformly from galaxy to galaxy. Astronomers used the NASA/ESA Hubble Space Telescope to identify over 11 000 globular clusters in the Virgo cluster of galaxies, most of which are more than 5 billion years old. Comprised of over 2 000 galaxies, the Virgo cluster is located about 54 million light-years away and is the nearest large galaxy cluster to Earth. Along with Virgo, the sharp vision of Hubble's Advanced Camera for Surveys (ACS) resolved the star clusters in 100 galaxies of various sizes, shapes, and brightness – even in faint, dwarf galaxies. "It's hard to distinguish globular clusters from stars and galaxies using ground-based telescopes", explained Eric Peng of Peking University in Beijing, China, and lead author of the Hubble study. Hubble’s “eye” is so sharp that it was able to pick out the fuzzy globular clusters from stars in our galaxy and from faraway galaxies in the background. "With Hubble we were able to identify and study about 90 percent of the globular clusters in all our observed fields. This was crucial for dwarf galaxies that have only a handful of star clusters". The team found a bounty of globular clusters (from a few dozen to several dozen) in most of the dwarf galaxies within 3 million light-years of the cluster’s centre. This happens to be the same region where the giant elliptical galaxy Messier 87 resides. These numbers were surprisingly high considering the low masses of the dwarfs they inhabited. By contrast, dwarfs in the outskirts of the cluster had fewer globulars. “Our study shows that the efficiency of star cluster formation depends on the environment”, said Patrick Cote of the Herzberg Institute of Astrophysics in Victoria, Canada. “Dwarf galaxies closest to Virgo's crowded centre contained more globular clusters than those farther away”. Astronomers have long known that the giant elliptical galaxy at the cluster’s centre, Messier 87, also hosts a larger than predicted population of globular star clusters. However, the origin of so many globulars has been a long-standing mystery. Astronomers have theorised that many of the clusters may have been snatched from smaller galaxies that ventured too close to it. “We found few or no globular clusters in galaxies within 130 000 light-years from Messier 87, suggesting the giant galaxy stripped the smaller ones of their star clusters”, Peng said. “These smaller galaxies are contributing to the buildup of Messier 87”. Evidence of Messier 87’s galactic cannibalism comes from an analysis of the globular clusters’ composition. “In Messier 87 there are three times as many globulars deficient in heavy elements, such as iron, than globulars rich in those elements”, Peng said. “This suggests that many of these ‘metal-poor’ star clusters may have been stolen from nearby dwarf galaxies, which also contain globulars deficient in heavy elements”. Studying globular star clusters is critical to understanding the early, intense star-forming episodes that mark galaxy formation. They are known to reside in all but the faintest of galaxies. “Star formation near the core of Virgo is very intense and occurs in a small volume over a short amount of time”, Peng noted. “It may be more rapid and more efficient than star formation in the outskirts. The high star-formation rate may be driven by the gravitational collapse of dark matter, an invisible form of matter, which is denser and collapses sooner near the cluster's centre. Messier 87 sits at the centre of a large concentration of dark matter, and all of these globulars near the centre probably formed early in the history of the Virgo cluster.” The smaller number of globular clusters in the dwarf galaxies sitting farther away from the centre may be due to the masses of the star clusters that formed, Peng said. “Star formation farther away from the central region was not as robust, which may have produced only less massive star clusters that dissipated over time”, he explained. The astronomers also obtained accurate distances to 84 of the 100 galaxies in the Hubble study. The results appeared on 1 July 2008 in The Astrophysical Journal. Notes for editors: The Hubble Space Telescope is a project of international cooperation between ESA and NASA. Image credit: NASA, ESA and Eric Peng (Peking University, China) Links: Science paper NASA News Release Contacts: Eric Peng Peking University, Beijing, China Tel: +86-10-6275-8629 E-mail: peng@bac.pku.edu.cn Lars Lindberg Christensen Hubble/ESA, Garching, Germany Tel: +49-89-3200-6306 Cellular: +49-173-3872-621 E-mail: lars@eso.org Donna Weaver/Ray Villard Space Telescope Science Institute, Baltimore, USA Tel: +1-410-338-4493/+1-410-338-4514 E-mail: dweaver@stsci.edu/villard@stsci.edu

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Yale University : 'Cosmic ghost' discovered by volunteer astronomer

Hanny's Voorwerp and IC 2497.

When Yale astrophysicist Kevin Schawinski and his colleagues at Oxford University enlisted public support in cataloguing galaxies, they never envisioned the strange object Hanny van Arkel found in archived images of the night sky.

The Dutch school teacher, a volunteer in the Galaxy Zoo project that allows members of the public to take part in astronomy research online, discovered a mysterious and unique object some observers are calling a "cosmic ghost."

van Arkel came across the image of a strange, gaseous object with a hole in the center while using the www.galaxyzoo.org website to classify images of galaxies.

When she posted about the image that quickly became known as "Hanny's Voorwerp" ( Dutch for "object") on the Galaxy Zoo forum, astronomers who run the site began to investigate and soon realized van Arkel might have found a new class of astronomical object.

"At first, we had no idea what it was. It could have been in our solar system, or at the edge of the universe," said Schawinski, a member and co-founder of the Galaxy Zoo team.

Scientists working at telescopes around the world and with satellites in space were asked to take a look at the mysterious Voorwerp. "What we saw was really a mystery," said Schawinski. "The Voorwerp didn't contain any stars." Rather, it was made entirely of gas so hot — about 10,000 Celsius — that the astronomers felt it had to be illuminated by something powerful. They will soon use the Hubble Space Telescope to get a closer look.

Since there was no obvious source at hand in the Voorwerp itself, the team looked to find the source of illumination around the Voorwerp, and soon turned to the nearby galaxy IC 2497.

"We think that in the recent past the galaxy IC 2497 hosted an enormously bright quasar," Schawinski explains. "Because of the vast scale of the galaxy and the Voorwerp, light from that past still lights up the nearby Voorwerp even though the quasar shut down sometime in the past 100,000 years, and the galaxy's black hole itself has gone quiet."

"From the point of view of the Voorwerp, the galaxy looks as bright as it would have before the black hole turned off – it's this light echo that has been frozen in time for us to observe," said Chris Lintott, a co-organizer of Galaxy Zoo at Oxford University, UK. "It's rather like examining the scene of a crime where, although we can't see them, we know the culprit must be lurking somewhere nearby in the shadows." Similar light echoes have been seen around supernovae that exploded decades or centuries ago.

Quasars are very unusual, highly luminous objects, powered by supermassive black holes, and most are extremely distant. "The strange 'Hanny's Voorwerp' looks like it could be the nearest example of a luminous quasar," said C. Megan Urry, Israel Munson Professor of Physics & Astronomy and Chair of the Physics Department at Yale, who was not involved in the research.

"IC 2497 is so close that if the quasar was still shining today, on a good night you could probably see it with a small telescope," Schawinski added. "The nearest active quasar, called 3C 273, is 1.7 billion light years further away."

"This discovery really shows how citizen science has come of age in the Internet world," commented Professor Bill Keel of the University of Alabama, a galaxyzoo.org team member. "Hanny's attentiveness alerted us not only to a peculiar object, but to a window into the cosmic past which might have eluded us for a long time otherwise. Trying to understand the processes operating here has proven to be a fascinating challenge, involving a whole range of astrophysical techniques and instruments around the world and beyond. This has also been some of the most rewarding astronomy I've done in years!"

The Galaxy Zoo project was imagined and begun by Schawinski and his colleague Chris Lintott at Oxford. While working on his PhD thesis, Schawinski classified and catalogued nearly 50,000 galaxies. Knowing that the human eye is sometimes more sensitive than a computer at picking out unusual patterns, he mused that it would be wonderful if there were amateur astronomers who were interested in doing some of the "scanning."

"When we launched Galaxy Zoo we were overwhelmed — as was the internet portal, initially — with the outpouring of public interest and volunteer input," said Schawinski. During the last year, over 150,000 armchair astronomers from all over the world volunteered their time and submitted over 50 million classifications for a set of one million images online. They then could follow the progress of the science they made possible at www.galaxyzooblog.org .

"It's amazing to think that this object has been sitting in the archives for decades and that amateur volunteers can help by spotting things like this online," said Hanny van Arkel. "It was a fantastic present to find out on my 25th birthday that we will get observational time on the Hubble Space Telescope to follow-up this discovery."

The next stage of Galaxy Zoo will ask volunteers to search for more unusual astronomical objects. But, "Hanny's Voorwerp" remains a mystery. It's huge central hole is over 16,000 light years across and Galaxy Zoo astronomers are still puzzling over what caused it.

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The new digital images used in Galaxy Zoo were taken using the robotic Sloan Digital Sky Survey telescope in New Mexico. More on the Sloan Digital Sky Survey is at www.sdss.org . For full details of those involved see www.sdss.org/collaboration/credits.html.

Besides Schawinski, the Galaxy Zoo team includes scientists from the University of Oxford, the University of Portsmouth and Johns Hopkins University (USA), and Fingerprint Digital Media of Belfast. Key contributors to this stage of the project were Chris Lintott from the University of Oxford, Bill Keel from the University of Alabama (USA), Dan Smith (Liverpool John Moores University) Matt Jarvis (University of Hertfordshire) and Nicola Bennert (University of California Riverside, USA). The team's observations and analysis are included in a paper which has been submitted to the Monthly Notices of the Royal Astronomical Society, the UK's leading astronomical journal. For more information, visit www.galaxyzoo.org

Images related to the project can be downloaded from http://www.ox.ac.uk/media/news_releases_for_journalists/gzvimages.html. A netcast interview with Kevin Schawinski is available on iTunesU in the Science section and on the Yale Public Affairs site at http://feeds.feedburner.com/yale/science.

Washington University in St. Louis : Superfluid-superconductor relationship is detailed

2 super phenomena

Scientists have studied superconductors and superfluids for decades. Now, researchers at Washington University in St. Louis have drawn the first detailed picture of the way a superfluid influences the behavior of a superconductor. In addition to describing previously unknown superconductor behavior, these calculations could change scientists' understanding of the motion of neutron stars.

A neutron star, the high-density remnant of a former massive star, is thought to contain both a neutron superfluid and a proton superconductor at its core. Despite widespread agreement that neutron stars contain both materials, superfluid-superconductors have not been widely studied.

"Not many people have thought seriously about the interactions between a superfluid and a superconductor that are co-existing like this," said Mark Alford, associate professor of physics and lead author of the paper published in the July issue of Physical Review B, "They tended to treat the two components separately."

Super Phenomena

Separately, the two phenomena are well understood. A superconductor allows a flow of current without resistance. Similarly, a superfluid flows without friction. Unlike superconductors and superfluids, a superfluid-superconductor does not exist on earth. But, understanding its hybrid behavior may be a first step toward creating one in the lab and understanding what goes on inside neutron stars.

In addition to conducting current without resistance, superconductors also exclude magnetic fields. Neutron stars have massive magnetic fields, but scientists do not know how a superconductor behaves in the presence of this field, specifically whether it will be a type I or type II superconductor. A type I superconductor forces a magnetic field around its exterior. A type II superconductor, however, strikes a compromise, letting the magnetic field pass through tiny non-superconducting holes called flux tubes. Type II superconductors permit one unit of magnetic field per flux tube.

Whether a superconductor is type I or type II depends on a value called kappa. If kappa is greater than a set critical value, the superconductor is type II. Likewise, if kappa is less than the critical value, the superconductor is type I. Add a superfluid, however, and these calculations show that the superconductor's boundary shifts, changing the critical value of kappa and causing exotic behavior at the boundary.

Living on the Edge

Ariel Zhitnitsky at the University of British Columbia was the first to report this boundary shift. Curiosity piqued by the shift, Alford and his collaborator, graduate student Gerald Good, decided to take a closer look at the boundary.

"We found that the boundary wasn't just shifted, but new behavior appeared when the superconductor is on the edge, between type I and type II," said Alford. Since superconductors and superfluids are older physics, Alford added, "We were surprised that there was anything new to mine here."

To understand the boundary shift, Alford and Good examined two interactions between the superfluid and superconductor. The first had a superconductor either attracting or repelling a superfluid. The second had a flowing superconductor causing a superfluid to flow either with it or against it.

Exotic Behavior at the Shifted Boundary

Alford and Good found that the two superconductor-superfluid interactions (attractive/repulsive and flow) had opposite effects on the boundary shift and produced different, but equally exotic, boundary behavior.

The attractive/repulsive interaction increased kappa, favoring a type I superconductor and creating intermediate type II states near the boundary. These intermediate states resemble type II because they have flux tubes; but strangely, more than one unit of magnetic field appears to exist in each. Depending on the parameters, an infinite number of intermediate type II states exist, with any number of magnetic field units in each flux tube.

Unlike the attractive/repulsive interaction, the flow interaction decreased kappa, favoring a type II superconductor. Instead of intermediate type II states, the flow interaction creates meta-stable regions on either side of the boundary. Specifically, in these regions a superconductor that should be type II can get stuck as type I and vice versa. A familiar example of similar behavior is when, under the right conditions, water remains a liquid despite freezing temperatures.

Passing the Baton

Just as Zhitnitsky's work inspired Alford and Good to look closer at the type I/type II boundary, this work has already spurred others in new directions. A group at Dartmouth College is confirming some behavior seen by Alford and Good, but the Dartmouth results favor a different scenario for the intermediate type II phases (unpublished).

The Dartmouth group is not seeing multiple units of magnetic field in one flux tube, but flux tubes that are a fixed distance apart (with one unit of magnetic field each). These flux tubes tend to "stick together" rather than spread out as far as possible, as in normal type II superconductors. Alford and Good said they could not rule out this possibility due to limitations in the simplified model and in computing capacity.

"The Dartmouth group is seeing similar intermediate phases," said Good, "but slightly different behavior. That's the next step in our research and it's already being done, which is pretty neat."

European Space Agency : COROT finds exoplanet orbiting Sun-like star

Artist's impression of COROT

COROT finds exoplanet orbiting Sun-like star

24 July 2008
A team of European scientists working with COROT have discovered an exoplanet orbiting a star slightly more massive than the Sun. After just 555 days in orbit, the mission has now observed more than

50 000 stars and is adding significantly to our knowledge of the fundamental workings of stars. The latest discovery, COROT-exo-4b is an exoplanet of about the same size as Jupiter. It takes 9.2 days to orbit its star, the longest period for any transiting exoplanet ever found. The team has found that the star, which is slightly larger than our Sun, is rotating at the same pace as the planet's period of revolution. This is quite a surprise for the team, as the planet is thought to be too low in mass and too distant from its star, for the star to have any major influence on its rotation. Light-curve of COROT-exo-4b's parent star Launched in December 2006, COROT is the first space-based mission designed to search for exoplanets. Located outside Earth's atmosphere, the satellite is designed to detect rocky exoplanets almost as small as Earth. The satellite uses transits, the tiny dips in the light output from a star when a planet passes in front of it, to detect and study planets. This is followed up by extensive ground-based observations. Monitoring COROT-exo-4b continuously over several months, the team tracked variations in its brightness between transits. They derived its period of rotation by monitoring dark spots on its surface that rotated in and out of view. It is not known whether COROT-exo-4b and its star have always been rotating in sync since their formation about 1000 million years ago, or if the star’s rotation synchronized later. Studying such systems with COROT will help scientists gain valuable insight into star-planet interactions. This is the first transiting exoplanet found with such a peculiar combination of mass and period of rotation. There is surely something special about how it formed and evolved. Notes for editors: This discovery is being presented today at the Cool Stars 15 meeting at St Andrews University. The ground-based follow-up of the detection of COROT-exo-4b was carried out with the cross-dispersed echelle spectrograph, SOPHIE, on the 1.8-m telescope at the Observatoire de Haute Provence (France), the High Accuracy Radial velocity Planet Searcher, HARPS on the 3.6-m telescope at La Silla observatory (Chile) and the cross-dispersed echelle spectrograph, UVES on the 8.2-m Very Large Telescope at Paranal (Chile), the 1-m telescope at the Wise Observatory in Israel, the 1-m Euler telescope at La Silla, and the 3.6-m Canada-France-Hawaii telescope. COROT is a CNES project with ESA participation. The other major partners in this mission are Austria, Belgium, Brazil, Germany and Spain. For more information: Malcolm Fridlund, ESA COROT Project Scientist Email: Malcolm.Fridlund @ esa.int

ESO : Watching a 'New Star' Make the Universe Dusty

VLTI observes for the first time how dust forms around an erupting star

Using ESO's Very Large Telescope Interferometer, and its remarkable acuity, astronomers were able for the first time to witness the appearance of a shell of dusty gas around a star that had just erupted, and follow its evolution for more than 100 days. This provides the astronomers with a new way to estimate the distance of this object and obtain invaluable information on the operating mode of stellar vampires, dense stars that suck material from a companion.

ESO PR Photo 22/08
Dust shells around a nova

Although novae were first thought to be new stars appearing in the sky, hence their Latin name, they are now understood as signaling the brightening of a small, dense star. Novae occur in double star systems comprising a white dwarf - the end product of a solar-like star - and, generally, a low-mass normal star - a red dwarf. The two stars are so close together that the red dwarf cannot hold itself together and loses mass to its companion. Occasionally, the shell of matter that has fallen onto the ingesting star becomes unstable, leading to a thermonuclear explosion which makes the system brighter.

Nova Scorpii 2007a (or V1280 Scorpii), was discovered by Japanese amateur astronomers on 4 February 2007 towards the constellation Scorpius ("the Scorpion"). For a few days, it became brighter and brighter, reaching its maximum on 17 February, to become one of the brightest novae of the last 35 years. At that time, it was easily visible with the unaided eye.

Eleven days after reaching its maximum, astronomers witnessed the formation of dust around the object. Dust was present for more than 200 days, as the nova only slowly emerged from the smoke between October and November 2007. During these 200 days, the erupting source was screened out efficiently, becoming more than 10,000 times dimmer in the visual.

An unprecedented high spatial resolution monitoring of the dust formation event was carried out with the Very Large Telescope Interferometer (VLTI), extending over more than 5 months following the discovery. The astronomers first used the AMBER near-infrared instrument, then, as the nova continued to produce dust at a high rate, they moved to using the MIDI mid-infrared instrument, that is more sensitive to the radiation of the hot dust. Similarly, as the nova became fainter, the astronomers switched from the 1.8-m Auxiliary Telescopes to their larger brethren, the 8.2-m Unit Telescopes. With the interferometry mode, the resolution obtained is equivalent to using a telescope with a size between 35 and 71 metres (the distance between the 2 telescopes used).

The first observations, secured 23 days after the discovery, showed that the source was very compact, less than 1 thousandth of an arcsecond (1 milli-arcsecond or mas), which is a size comparable to viewing one grain of sand from about 100 kilometres away. A few days later, after the detection of the major dust formation event, the source measured 13 mas.

"It is most likely that the latter size corresponds to the diameter of the dust shell in expansion, while the size previously measured was an upper limit of the erupting source," explains lead author Olivier Chesneau. Over the following months the dusty shell expanded regularly, at a rate close to 2 million km/h.

"This is the first time that the dust shell of a nova is spatially resolved and its evolution traced starting from the onset of its formation up to the point that it becomes too diluted to be seen", says co-author Dipankar Banerjee, from India.

The measurement of the angular expansion rate, together with the knowledge of the expansion velocity, enables the astronomer to derive the distance of the object, in this case about 5500 light-years.

"This is a new and promising technique for providing distances of close novae. This was made possible because the state of the art facility of the VLTI, both in terms of infrastructure and management of the observations, allows one to schedule such observations," says co-author Markus Wittkowski from ESO.

Moreover, the quality of the data provided by the VLTI was such that it was possible to estimate the daily production of dust and infer the total mass ejected. "Overall, V1280 Sco probably ejected more than the equivalent of 33 times the mass of the Earth, a rather impressive feat if one considers that this mass was ejected from a star not larger in radius than the Earth," concludes Chesneau. Of this material, about a percent or less was in the form of dust.

More information

"VLTI monitoring of the dust formation event of the Nova V1280 Sco", by O. Chesneau et al. appears today in the research journal Astronomy and Astrophysics.

The team is composed of O. Chesneau, S. Sacuto, and A. Spang (CNRS/OCA, Grasse, France), D. P. K. Banerjee, N. M. Ashok and R. K. Das, (Physical Research Laboratory, Gujarat, India), F. Millour, N. Nardetto and S. Kraus (Max-Planck-Institut für Radioastronomie, Bonn, Germany), E. Lagadec (Department of Physics and Astronomy University of Manchester, UK), and M. Wittkowski, C. Hummel, M. Petr-Gotzens, S. Morel, F. Rantakyro, and M. Schöller (ESO).
A French press release is available at http://fizeau.unice.fr/article.php3?id_article=189

Contacts

Olivier Chesneau
Observatoire de la Côte d'Azur, Dpt. Fizeau
Grasse, France
Phone: +33 4 93 40 53 40
E-mail: Olivier.Chesneau (at) obs-azur.fr

ESA/Hubble Information Centre : Lenses galore - Hubble finds large sample of very distant galaxies

24-Jul-2008: New Hubble Space Telescope observations of six spectacular galaxy clusters acting as gravitational lenses have given significant insights into the early stages of the Universe. Scientists have found the largest sample of very distant galaxies seen to date: ten promising candidates thought to lie at a distance of 13 billion light-years (~redshift 7.5). By using the gravitational magnification from six massive lensing galaxy clusters, the NASA/ESA Hubble Space Telescope has provided scientists with the largest sample of very distant galaxies seen to date. Some of the newly found magnified objects are dimmer than the faintest ones seen in the legendary Hubble Ultra Deep Field, which is usually considered the deepest image of the Universe. By combining both visible and near-infrared observations from Hubble’s Advanced Camera for Surveys (ACS) and Near Infrared Camera and Multi-Object Spectrometer (NICMOS), scientists searched for galaxies that are only visible in near-infrared light. They uncovered 10 candidates believed to lie about 13 billion light-years away (a redshift of approximately 7.5), which means that the light gathered was emitted by the stars when the Universe was still very young — a mere 700 million years old. “These candidates could well explain one of the big puzzles plaguing astronomy today. We know that the Universe was reionised within the first 5-600 million years after the Big Bang, but we don’t know if the ionising energy came from a smaller number of big galaxies or a more plentiful population of tiny ones”, said Johan Richard, from the California Institute of Technology. The relatively high number of redshift 7.5 galaxies claimed in this survey suggests that most of the ionising energy was produced by dim and abundant galaxies rather than large, scarce ones. “The challenge for astronomers is that galaxies beyond a distance of 13 billion light-years (past a redshift of 7) are exceedingly faint and are only visible in the near-infrared — just at the limit of what Hubble can observe” explained Jean-Paul Kneib from the Laboratoire d’Astrophysique de Marseille. This new result was only made possible with some cosmic assistance in the form of gravitational lensing that magnified the light from the distant galaxies enough for Hubble to detect them. A firm confirmation of their distance was beyond even the capabilities of the 10-meter Keck telescope and must await powerful future ground-based telescopes. First observationally confirmed in 1979, gravitational lenses were predicted by Albert Einstein’s theory of General Relativity, a theory that allows astronomers to calculate the path of starlight as it moves through curved space-time. According to the theory, the bending of light is brought about by the presence of matter in the Universe, which causes the fabric of space-time to warp and curve. Gravitational lensing is the result of this warping of spacetime and is mainly detected around very massive galaxy clusters. Due to the gravitational effect of both the cluster’s observable matter and hidden dark matter, the light is bent around the cluster. This bending of light allows the clusters in certain places to act as natural gravitational telescopes that give the light of faint and faraway objects a boost. Where Earth-bound telescopes fail to detect such faint and distant objects due to the blurring introduced by the Earth’s atmosphere, a combination of Hubble’s location in space and the magnification of the gravitation lenses provides astronomers with a birds-eye view of these elusive objects. This technique has already been used numerous times by Hubble and has helped astronomers to find and study many of the most distant known galaxies. Notes for editors: The Hubble Space Telescope is a project of international cooperation between ESA and NASA. Image credit: NASA, ESA and Johan Richard (Caltech, USA) Acknowledgement: Davide de Martin & James Long (ESA/Hubble) Links: Science paper Wikipedia site explaining Gravitational Lensing More Hubble discoveries relating to gravitational lenses Contacts: Johan Richard Department of Astrophysics, California Institute of Technology Tel: +1-626-395-3293 E-mail: johan@astro.caltech.edu Jean-Paul Kneib Department of Astrophysics, California Institute of Technology Laboratoire d'Astrophysique de Marseille Cell: +33-685-988-265 E-mail: jean-paul.kneib@oamp.fr Richard Ellis Department of Astrophysics, Oxford California Institute of Technology Tel: +44-1865-283124 Cellular: +44-7885-403334 E-mail: rse@astro.caltech.edu Lars Lindberg Christensen Hubble/ESA, Garching, Germany Tel: +49-89-3200-6306 Cellular: +49-173-3872-621 E-mail: lars@eso.org

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Science and Technology Facilities Council : Polarised sunglasses see black hole disks

For the first time astronomers have found a way to get a clean view of the elusive disks of matter surrounding supermassive black holes. By using a polarising filter on the Science and Technology Facility Council’s UK Infrared Telescope (UKIRT) in Hawaii, they have been able to see through the clouds of dust which surround these black holes. This work is published on 24th July 2008 in Nature.

This figure schematically shows how the team's polarization observation works.

In a similar way that a fisherman would wear polarised sunglasses to help get rid of the glare from the water surface and allow him to see more clearly under the water, the filter on the telescope allowed the astronomers to see beyond surrounding clouds of dust and gas to the blue colour of the disk in infrared light.

It is believed that most, if not all, galaxies have a supermassive black hole in their centre, and this is an area of intense research within astronomy. Studying these black holes and discovering more about their structure can be difficult as they are so far away from us.

Also, the clouds of gas and dust which surround the black holes make it difficult to achieve a clean, uncontaminated spectrum of the black hole vicinity.

Andy Lawrence, of the University of Edinburgh's Institute for Astronomy, and co-investigator on the project, says “For decades there has been a theory that supermassive black holes should be accumulating materials in the form of a disk …but until now this has been impossible to test due to the contamination by the dust clouds.”

The team, led by Makoto Kishimoto of the Max Planck Institut fuer Radioastronomie, have found a way around this problem.

Looking at UKIRT on Mauna Kea through IRPOL

Some of the black holes have a very small amount of scattered light coming from the vicinity of the black hole itself, rather than the clouds of gas and dust around it. This light has become polarised after hitting matter within the disk. By using a filter that only allows this polarised light to come through and blocks out the unpolarised light from the gas clouds, they were able to visually eliminate them and reveal the disk.

This new method could help astronomers in their understanding of the outermost region of the disks where important questions are still to be answered: how and where the disk ends, and how material is being supplied to the disk.

Dr. Chris Davis of the Joint Astronomy Centre, the facility operating UKIRT, says: "UKIRT has long been at the forefront of infrared astronomy, and has been a leader in the niche area of infrared polarimetry for almost two decades. Without facilities like the infrared polarimeter (IRPOL), even with the very largest telescopes in the world, exciting discoveries like those of Kishimoto and his colleagues could not be made."

ESO : Accretion Discs Show Their True Colours

VLT observations of quasars reconcile observations with models

Quasars are the brilliant cores of remote galaxies, at the hearts of which lie supermassive black holes that can generate enough power to outshine the Sun a trillion times. These mighty power sources are fuelled by interstellar gas, thought to be sucked into the hole from a surrounding 'accretion disc'. A paper in this week's issue of the journal Nature, partly based on observations collected with ESO's Very Large Telescope, verifies a long-standing prediction about the intensely luminous radiation emitted by these accretion discs.

ESO PR Photo 21/08
Uncovering the inner disc

"Astronomers were puzzled by the fact that the best models of these discs couldn't quite be reconciled with some of the observations, in particular, with the fact that these discs did not appear as blue as they should be," explains lead-author Makoto Kishimoto.

Such a discrepancy could be the signal that there was something very wrong with the models. With his colleagues, he investigated this discrepancy by studying the polarised light from six quasars. This enabled them to demonstrate that the disc spectrum is as blue as predicted.

"The crucial observational difficulty here has been that the disc is surrounded by a much larger torus containing hot dust, whose light partly outshines that of the disc," says Kishimoto. "Because the light coming from the disc is scattered in the disc vicinity and thus polarised, by observing only polarised light from the quasars, one can uncover the buried light from the disc."

In a similar way that a fisherman would wear polarised sunglasses to help get rid of the glare from the water surface and allow him to see more clearly under the water, the filter on the telescope allowed the astronomers to see beyond surrounding clouds of dust and gas to the blue colour of the disc in infrared light.

The observations were done with the FORS and ISAAC instruments on one of the 8.2-m Unit Telescopes of ESO's Very Large Telescope, located in the Atacama Desert, in Chile, as well as several other telescopes, including STFC's UKIRT.

The standard picture of the accretion disc is therefore vindicated. The authors believe that further measurements could eventually provide valuable insight into how and where the disc ends, and how material is being supplied to the disc.

More information

"The characteristic blue spectra of accretion disks in quasars as uncovered in the infrared," by Makoto Kishimoto et al., appears in the 24 July 2008 issue of the journal Nature. The team is composed of Makoto Kishimoto (Max-Planck-Institut für Radioastronomie, Bonn, Germany), Robert Antonucci, Omer Blaes, and Christian Leipski (University of California, Santa Barbara, USA), Andy Lawrence (SUPA, University of Edinburgh, UK), Catherine Boisson (LUTH, Observatoire de Paris, France), and Marcus Albrecht (Universidad Catolica del Norte, Chile).

Contacts

Makoto Kishimoto
Max-Planck-Institut für Radioastronomie
Bonn, Germany
Phone: +49 228 525 186
E-mail: mk (at) mpifr-bonn.mpg.de

ESO Press Officer: Dr. Henri Boffin - +49 89 3200 6222 - hboffin@eso.org
ESO Press Officer in Chile: Valentina Rodriguez - +56 2 463 3123 - vrodrigu@eso.org

Physikalisch-Technische Bundesanstalt (PTB) : Shielding for ambitious neutron experiment

PTB expertise supports research for better understanding of antimaterial

In science fiction stories it is either the inexhaustible energy source of the future or a superweapon of galactic magnitude: antimaterial. In fact, antimaterial can neither be found on Earth nor in space, is extremely complex to produce and thus difficult to study. In order to nevertheless track down the origin of material and antimaterial in the universe, a European research group is measuring the power of the electrical dipole moment of neutrons, which represents a measure for the different physical properties of material and antimaterial. The prerequisite for further, still more accurate measurements is a perfect insulation against electrical and magnetic radiation from the environment. Magnetically soft mumetal serves as a material of the new shielding - the design, testing and set-up of which the Physikalisch-Technische Bundesanstalt is responsible.

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PTB-Contact:
Dr. Allard Schnabel, Fachbereich 8.2 Biosignale, Tel. (030) 3481-7423, E-Mail: Allard.Schnabel@ptb.de
Dr. Martin Burghoff, Fachbereich 8.2 Biosignale, Tel. (030) 3481-7238, E-Mail: Martin.Burghoff@ptb.de

Information on mu-metal cabin at PTB
http://www.ptb.de/en/publikationen/blickpunkt/_biomagnetismus.html

List of involved research institutions
http://nedm.web.psi.ch

Further PTB-News

• New law on the units of measurement (July 14)
• Detecting the smallest contaminations on semiconductors with... (July 10)
• Fighting tumour with the correct dose (July 9)
• Summer School provides metrology at its finest (July 3)

All news are available at http://www.ptb.de/

University of California - Los Angeles Scientists solve 30-year-old aurora borealis mystery

UCLA space scientists and colleagues have identified the mechanism that triggers substorms in space; wreaks havoc on satellites, power grids and communications systems; and leads to the explosive release of energy that causes the spectacular brightening of the aurora borealis, also known as the northern lights.

For 30 years, there have been two competing theories to explain the onset of these substorms, which are energy releases in the Earth's magnetosphere, said Vassilis Angelopoulos, a UCLA professor of Earth and space sciences and principal investigator of the NASA-funded mission known as THEMIS (Time History of Events and Macroscale Interactions during Substorms).

One theory is that the trigger happens relatively close to Earth, about one-sixth of the distance to the moon. According to this theory, large currents building up in the space environment, which is composed of charged ions and electrons, or "plasma," are suddenly released by an explosive instability. The plasma implodes toward Earth as the space currents are disrupted, which is the start of the substorm.

A second theory says the trigger is farther out, about one-third of the distance to the moon, and involves a different process: When two magnetic field lines come close together due to the storage of energy from the sun, a critical limit is reached and the magnetic field lines reconnect, causing magnetic energy to be transformed into kinetic energy and heat. Energy is released, and the plasma is accelerated, producing accelerated electrons.

Which theory is right?

"Our data show clearly and for the first time that magnetic reconnection is the trigger," said Angelopoulos, who reports the research in the July 24 online issue of the journal Science. "Reconnection results in a slingshot acceleration of waves and plasma along magnetic field lines, lighting up the aurora underneath even before the near-Earth space has had a chance to respond. We are providing the evidence that this is happening."

Previous studies of the Earth's magnetosphere and space weather have been unable to pinpoint the origin of substorms, which are large magnetic disturbances. Ionized gas emitted from the sun's surface speeds up as it moves away from the sun, attaining speeds of 1 million mph and interacting with the Earth's upper atmosphere, which is also ionized, Angelopoulos said. Substorms are building blocks of larger storms.

"We need to understand this environment and eventually be able to predict when these large energy releases will happen so astronauts can go inside their spacecraft and we can turn off critical systems on satellites so they will not be damaged," Angelopoulos said. "This has been exceedingly difficult in the past, because previous missions, which measured the plasma at one location, were unable to determine the origin of the large space storms. To resolve this question properly requires correlations and signal-timing at multiple locations. This is precisely what was missing until now."

At high northern latitudes in the northern U.S. and Canada, shimmering bands of light called the aurora borealis, or northern lights, stretch across the sky from the east to the west. During the geomagnetically disturbed periods known as substorms, these bands of light brighten. These multicolored light shows are generated when showers of high-speed electrons descend along magnetic field lines to strike the Earth's upper atmosphere. Scientists want to learn when, where and why solar wind energy stored within the Earth's magnetosphere is explosively released to accelerate these electrons.

THEMIS is establishing for the first time when and where substorms begin, determining how the individual components of substorms interact, and discovering how substorms power the aurora borealis.

"We discovered what sparks the magnificent light show of the aurora," Angelopoulos said.

THEMIS has five satellites — with electric, magnetic, ion and electron detectors — in carefully chosen orbits around the Earth and an array of 20 ground observatories with automated, all-sky cameras located in the northern U.S. and Canada that catch substorms as they happen. The ground observatories take images of the aurora in white light. One satellite is a third of the distance to the moon, one is about a fourth of the distance and three are about a sixth of the distance. The outermost satellite takes four days to orbit the Earth, the next one two days, and the closest ones orbit the Earth in just one day. Every four days, the satellites line up.

As the satellites are measuring the magnetic and electric fields of the plasma above the Earth's atmosphere once every four days, the ground-based observatories are imaging the auroral lights and the electrical currents from space that generate them.

THEMIS was launched on Feb. 17, 2007, from Cape Canaveral, Fla., and is expected to observe approximately 30 substorms in its nominal lifetime.

"Armed with this knowledge, we are not only putting to rest age-old questions about the origin of the spectacular auroral eruptions but will also be able to provide statistics on substorm evolution and model its effects on space weather," Angelopoulos said.

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Themis was the blindfolded Greek goddess of order and justice.

The project received a NASA outstanding performance group award this May. THEMIS is managed by the Explorers Program Office at Goddard Space Flight Center in Maryland.

THEMIS mission co-investigators include Christopher T. Russell, UCLA professor of geophysics and space physics and a co-author on the Science paper; Margaret G. Kivelson, professor of space physics in the UCLA Department of Earth and Space Sciences; Krishan Khurana, a researcher in the UCLA Department of Earth and Space Sciences; and scientists from UC Berkeley, where the mission was put together and half the instruments were built, Germany, Austria, France, Russia, Japan, Canada and the U.S.

In 1619 A.D., Galileo Galilei coined the term "aurora borealis" after Aurora, the Roman goddess of morning. He had the misconception that the auroras he saw were due to sunlight reflecting from the atmosphere.

For more information on the THEMIS mission, visit http://themis.ssl.berkeley.edu/ and www.nasa.gov/themis.

UCLA is California's largest university, with an enrollment of nearly 37,000 undergraduate and graduate students. The UCLA College of Letters and Science and the university's 11 professional schools feature renowned faculty and offer more than 300 degree programs and majors. UCLA is a national and international leader in the breadth and quality of its academic, research, health care, cultural, continuing education and athletic programs. Four alumni and five faculty have been awarded the Nobel Prize.

European Space Agency : GOCE prepares for shipment to Russia

GOCE in ESA's test facilities

Launching in just two months' time, GOCE – now fully reconfigured for launch in September, is currently being prepared for shipment on 29 July 2008 from ESA's test facilities in the Netherlands to the Plesetsk Cosmodrome in northern Russia.

Originally, the Gravity field and steady-state Ocean Circulation Explorer (GOCE) mission had been scheduled for launch in May 2008, but as a result of precautionary measures taken following a problem with an upper-stage section of a Russian Proton launcher, the launch date was postponed until 10 September 2008. Consequently, the satellite had to be reconfigured for a so-called 'summer launch configuration'.

	Rockot fairing opens three minutes after launch

Since the GOCE gravity mission is designed to fly at a particularly low altitude of just 263 km and at a slight inclination with respect to an exact polar orbit, the satellite goes into the shadow of the Earth during polar nights for 28 minutes 135 days each year.

By going into the Earth’s shadow where no sun hits the satellite, GOCE experiences changes in temperature that could potentially affect measurements. Not knowing exactly when GOCE would launch, the option to choose whether it went into Earth’s shadow, referred to as an ‘eclipse period’, between October and February or between April and August was included in its design.


The choice between these two options is made by either launching into a northward equator crossing at 06:00 or at 18:00. The main difference between the launch times – as seen from the Sun – is that it determines whether the satellite flies clockwise or anticlockwise around the Earth.

Since GOCE will launch in September, the preferred eclipse period is April to August because it allows unaffected commissioning and science operations until April next year.

GOCE in orbit

Over the last two months the satellite has been successfully reconfigured and fully tested and is now in the process of being prepared for its journey from ESA-ESTEC to the launch site in Russia.

On the morning of 29 July a container holding the GOCE satellite, along with six other containers carrying a whole host of support equipment, will be loaded onto trucks and taken to Schiphol Airport near Amsterdam in the Netherlands.

Once aboard an Antonov cargo aircraft, the shipment will be flown to Arkhangelsk, Russia, where the container will be transferred to a train for the rest of the journey to the Plesetsk Cosmodrome. Additional support equipment is being transported by ship to the launch site on 21 July from Antwerp, Belgium.

After the satellite is unpacked, a final check will be carried out before being mounted onto its Rockot launch vehicle 13 days prior to launch.

	The Earth's gravity field (geoid) as it will be seen by GOCE

Once launched and commissioned, GOCE will map global variations in the gravity field with extreme detail and accuracy. This will result in a unique model of the geoid, which is the surface of equal gravitational potential defined by the gravity field – crucial for deriving accurate measurements of ocean circulation and sea-level change, both of which are affected by climate change.

GOCE-derived data is also much needed to understand more about processes occurring inside the Earth and for use in practical applications such as surveying and levelling.