samedi 14 septembre 2013

ESA's GOCE Mission to End this Year









ESA - GOCE Mission logo.

14 September 2013

After more than four years mapping Earth’s gravity with unrivalled precision, GOCE’s mission is nearing its end and the satellite will soon reenter our atmosphere.

GOCE sapcecraft

The Gravity field and steady-state Ocean Circulation Explorer – GOCE – has been orbiting Earth since March 2009 at the lowest altitude of any research satellite.

With a sleek, aerodynamic design responsible for it being dubbed the ‘Ferrari of space’, GOCE has mapped variations in Earth’s gravity with extreme detail.

The result is a unique model of the ‘geoid’, which is essentially a virtual surface where water does not flow from one point to another.

In mid-October, the mission will come to a natural end when it runs out of fuel and the satellite begins its descent towards Earth from a height of about 224 km.

While most of GOCE will disintegrate in the atmosphere, several parts might reach Earth’s surface.

GOCE geoid

When and where these parts might land cannot yet be predicted, but the affected area will be narrowed down closer to the time of reentry. Reentry is expected to happen about three weeks after the fuel is depleted. 

Taking into account that two thirds of Earth are covered by oceans and vast areas are thinly populated, the danger to life or property is very low.

About 40 tonnes of manmade space debris reach the ground per year, but the spread and size mean the risk of an individual being struck is lower than being hit by a meteorite.

An international campaign is monitoring the descent, involving the Inter-Agency Space Debris Coordination Committee. The situation is being continuously watched by ESA’s Space Debris Office, which will issue reentry predictions and risk assessments.

ESA will keep its Member States and the relevant safety authorities permanently updated.

Related links:

ESA Space Debris Office: http://www.esa.int/Our_Activities/Operations/Ground_Systems_Engineering/ESA_Space_Debris_Office

Inter-Agency Space Debris Coordination Committee: http://www.iadc-online.org/

Access GOCE data: http://earth.esa.int/GOCE/

Images, Text, Credits: ESA / AOES Medialab / HPF / DLR.

Best regards, Orbiter.ch

Launch Result of Epsilon-1 with SPRINT-A aboard








JAXA logo.

September 14, 2013 (JST)

 Artist's view of the launch of the Epsilon-1 rocket

Japan Aerospace Exploration Agency launched the first Epsilon Launch Vehicle (Epsilon-1) with the Spectroscopic Planet Observatory for Recognition of Interaction of Atmosphere (SPRINT-A) onboard at 2:00 p.m. on September 14 (Sat.), 2013 (Japan Standard Time, JST) from the Uchinoura Space Center.

video
Epsilon-1 Launch Sep.14.2013

The launch vehicle flew smoothly, and, at about 61 minutes and 39 seconds after liftoff, the separation of the SPRINT-A was confirmed.


Image above: Epsilon-1 description:

(1) Vertical line (thin line): showing our one-step-up evolution and streamlining from our conventional development policy
(2) Logo: sharp lines and a big E emphasize "Epsilon (ε)"
(3) Star mark: indicating our strong desire and intention to probe planets
(4) Vertical line (thick line): shows our magnificent history from the Pencil Rocket through the M-V Launch Vehicle.
(5) Zone line (all around the launch vehicle): our traditional coloring with two colors for our solid-fuel launch vehicles.

We would like to express our profound appreciation for the cooperation and support of all related personnel and organizations that helped contribute to the launch of the Epsilon-1.

Artist's view of the SPRINT-A spacecraft

At the time of the launch, the weather was cloudy, a wind speed was 8.1 meters/second from the east-north-east and the temperature was 27.2 degrees Celsius.

Epsilon Launch Vehicle (Epsilon-1)

Launch Sequence (Quick Review):


*1 The values are based on quick report results before detailed data evaluation.

Mission website:

Epsilon Launch Vehicle/SPRINT-A Special Site: http://www.jaxa.jp/countdown/epsilon/index_e.html

Epsilon Launch Vehicle: http://www.jaxa.jp/projects/rockets/epsilon/index_e.html

Spectroscopic Planet Observatory for Recognitionof Interaction of Atmosphere (SPRINT-A): http://www.jaxa.jp/projects/sat/sprint_a/index_e.html

Images, Video, Text, Credits: Japan Aerospace Exploration Agency (JAXA).

Greetings, Orbiter.ch

vendredi 13 septembre 2013

New Hubble image of galaxy cluster Abell 1689












ESA - Hubble Space Telescope logo.

13 September 2013

 New Hubble view of galaxy cluster Abell 1689

This new image from Hubble is one of the best ever views of the massive galaxy cluster Abell 1689, and shows the phenomenon of gravitational lensing with unprecedented clarity. This cluster acts like a cosmic lens, magnifying the light from objects lying behind it and making it possible for astronomers to explore incredibly distant regions of space. As well as being packed with galaxies, Abell 1689 has been found to host a huge population of globular clusters.

Hubble previously observed this cluster back in 2002. However, this new image combines visible and infrared data from Hubble’s Advanced Camera for Surveys (ACS) to reveal this patch of sky in greater detail than ever before, with a combined total exposure time of over 34 hours.

Globular clusters within Abell 1689

These new, deeper, observations were taken in order to explore the globular clusters within Abell 1689 [1]. This new study has shown that Abell 1689 hosts the largest population of globular clusters ever found. While our galaxy, the Milky Way, is only home to around 150 of these old clumps of stars, Hubble has spied some 10 000 globular clusters within Abell 1689. From this, the astronomers estimate that this galaxy cluster could possibly contain over 160 000 globulars overall – an unprecedented number.

This is not the first time that this trusty magnifying glass has helped astronomer detectives try to solve clues about the Universe. In 2010, astronomers were able to investigate the elusive phenomena of dark matter and dark energy by mapping the composition of Abell 1689 (opo1037a, heic1014). Its powers as a zoom lens also enabled Hubble to identify a galaxy dubbed A1689-zD1 in 2008, one of the youngest and brightest galaxies ever seen at the time (heic0805).

A snapshot of Abell 1689's globular clusters

This image is peppered with glowing golden clumps, bright stars, and distant, ethereal spiral galaxies. Material from some of these galaxies is being stripped away, giving the impression that the galaxy is dripping into the surrounding space. Also visible are a number of electric blue streaks, circling and arcing around the fuzzy galaxies in the centre [2].

These streaks are the tell-tale signs of a cosmic phenomenon known as gravitational lensing. Abell 1689 is so massive that it actually bends and warps the space around it, affecting how light from objects behind the cluster travels through space. These streaks are actually the distorted forms of galaxies that lie behind Abell 1689.

Wide-field image of the Virgo constellation (ground-based image)

Other galaxy clusters like Abell 1689 will be observed by Hubble during the upcoming Frontier Fields programme, which will exploit the magnifying powers of massive gravitational lenses to see even further into the distant Universe.

video
Pan across galaxy cluster Abell 1689

Notes:

[1] Globular clusters are dense collections of hundreds of thousands of stars — some of the oldest surviving stars in the Universe.

[2] These streaks appear to be blue because the galaxies that form them are furiously forming very hot new stars. The emission from these hot young stars causes the blue hue.

More information:

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

A paper describing the observations of globular clusters within Abell 1689, entitled “The rich globular cluster system of Abell 1689 and the radial dependence of the globular cluster formation efficiency”, will appear in the 20 September issue of The Astrophysical Journal (and is available online here). This study was led by K. A. Alamo-Martinez (Universidad Nacional Autonoma de Mexico, Mexico; Herzberg Institute of Astrophysics, Canada) and J. P. Blakeslee (Herzberg Institute of Astrophysics, Canada).

Links:
NASA press release: http://hubblesite.org/newscenter/archive/releases/2013/36/

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

Images, Text, Credits: NASA, ESA, J. Blakeslee (NRC Herzberg Astrophysics Program, Dominion Astrophysical Observatory), and K. Alamo-Martinez (National Autonomous University of Mexico)
Acknowledgment: H. Ford (JHU)/Digitized Sky Survey 2. Acknowledgment: Davide De Martin (ESA/Hubble)/Video: NASA, ESA, the Hubble Heritage Team (STScI/AURA), J. Blakeslee (NRC Herzberg Astrophysics Program, Dominion Astrophysical Observatory), and H. Ford (JHU). Music: movetwo.

Best regards, Orbiter.ch

Arc Across the Planet Saturn












NASA / ESA - Cassini Mission to Saturn patch.

Sept. 13, 2013


Saturn's rings appear to form a majestic arc over the planet in this image from NASA's Cassini spacecraft.

This view looks toward the sunlit side of the rings from about 17 degrees above the ringplane. The image was taken with the Cassini spacecraft wide-angle camera on June 15, 2013 using a spectral filter sensitive to wavelengths of near-infrared light centered at 705 nanometers.

The view was acquired at a distance of approximately 657,000 miles (1.1 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 2 degrees. Image scale is 37 miles (60 kilometers) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

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

Image, Text,  Credits: NASA / JPL-Caltech / Space Science Institute.

Cheers, Orbiter.ch

The Peanut at the Heart of our Galaxy












ESO - European Southern Observatory logo.

13 September 2013

ESO telescopes create the best 3D map yet of central bulge of the Milky Way

Artist's impression of the central bulge of the Milky Way

Two groups of astronomers have used data from ESO telescopes to make the best three-dimensional map yet of the central parts of the Milky Way. They have found that the inner regions take on a peanut-like, or X-shaped, appearance from some angles. This odd shape was mapped by using public data from ESO’s VISTA survey telescope along with measurements of the motions of hundreds of very faint stars in the central bulge.

The Galactic Centre and Bulge above the ESO 3.6-metre telescope

One of the most important and massive parts of the galaxy is the galactic bulge. This huge central cloud of about 10 000 million stars spans thousands of light-years, but its structure and origin were not well understood.

Part of the VVV view of the bulge of the Milky Way from ESO's VISTA

Unfortunately, from our vantage point from within the galactic disc, the view of this central region — at about 27 000 light-years’ distance — is heavily obscured by dense clouds of gas and dust. Astronomers can only obtain a good view of the bulge by observing longer wavelength light, such as infrared radiation, which can penetrate the dust clouds.

Hubble view of galaxy NGC 4710 with X-shaped bulge


Earlier observations from the 2MASS infrared sky survey had already hinted that the bulge had a mysterious X-shaped structure. Now two groups of scientists have used new observations from several of ESO’s telescopes to get a much clearer view of the bulge’s structure.

The first group, from the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, Germany, used the VVV near-infrared survey [1] from the VISTA telescope at ESO’s Paranal Observatory in Chile (eso1101, eso1128, eso1141, eso1242, eso1309). This new public survey can pick up stars thirty times fainter than previous bulge surveys. The team identified a total of 22 million stars belonging to a class of red giants whose well-known properties allow their distances to be calculated [2].

Artist's impression of the Milky Way (updated - annotated)

“The depth of the VISTA star catalogue far exceeds previous work and we can detect the entire population of these stars in all but the most highly obscured regions,” explains Christopher Wegg (MPE), who is lead author of the first study. “From this star distribution we can then make a three-dimensional map of the galactic bulge.This is the first time that such a map has been made without assuming a model for the bulge’s shape.”

Wide Field Imager view of part of the bulge of the Milky Way

"We find that the inner region of our Galaxy has the shape of a peanut in its shell from the side, and of a highly elongated bar from above", adds Ortwin Gerhard, the coauthor of the first paper and leader of the Dynamics Group at MPE [3].  "It is the first time that we can see this clearly in our own Milky Way, and simulations in our group and by others show that this shape is characteristic of a barred galaxy that started out as a pure disc of stars."

Artist's impression of the Milky Way

The second international team, led by Chilean PhD student Sergio Vásquez (Pontificia Universidad Católica de Chile, Santiago, Chile and ESO, Santiago, Chile) took a different approach to pin down the structure of the bulge. By comparing images taken eleven years apart with the MPG/ESO 2.2-metre telescope they could measure the tiny shifts due to the motions of the bulge stars across the sky. These were combined with measurements of the motions of the same stars towards or away from the Earth to map out the motions of more than 400 stars in three dimensions [4].

“This is the first time that a large number of velocities in three dimensions for individual stars from both sides of the bulge been obtained,” concludes Vásquez. “The stars we have observed seem to be streaming along the arms of the X-shaped bulge as their orbits take them up and down and out of the plane of the Milky Way. It all fits very well with predictions from state-of-the-art models!”

video
Artist's impression of the Milky Way

The astronomers think that the Milky Way was originally a pure disc of stars which formed a flat bar billions of years ago [5]. The inner part of this then buckled to form the three-dimensional peanut shape seen in the new observations.

video
 Simulation of the X-shaped bulge of the Milky Way

Notes:

[1] VVV stands for VISTA Variables in the Via Lactea Survey. This is one of six large surveys being made by the VISTA telescope. The data from the VVV survey is made publicly available to the international science community through the ESO Science Archive Facility which enabled the study at MPE.

[2] Red clump giant stars were chosen for this study as they can be used as a standard candles: at this stage in the giant stars’ lifetimes their luminosity is approximately independent of their age or composition. The amount of gas and dust obscuring the stars is calculated directly from the observed colours of the red clump stars, so that their brightness distribution without obscuration can be measured. Then, because red clump stars have nearly the same intrinsic brightness, this gives approximate distances to each star. The good spatial coverage of the VVV survey allowed measurements across the whole inner region of the Milky Way, and from these the three-dimensional measurement of the structure of the bulge was constructed.

[3] Similar peanut structures have been observed in the bulges of other galaxies and their formation has been predicted from computer simulations, which show that the peanut shape is formed by stars in orbits that form an X-shaped structure.

[4] The observations of these radial velocities were made using the FLAMES-GIRAFFE spectrograph on ESO’s Very Large Telescope and the IMACS spectrograph at the Las Campanas Observatory.

[5] Many galaxies, including the Milky Way, have long narrow features across their central regions, which are known as bars.

More information:

This research was presented in papers entitled “Mapping the three-dimensional density of the Galactic bulge with VVV red clump stars” by C. Wegg et al., to appear in the Monthly Notices of the Royal Astronomical Society, and “3D kinematics through the X-shaped Milky Way bulge”, by S. Vásquez et al., which has been recently published in the journal Astronomy & Astrophysics.

The first team is composed of C. Wegg and O. Gerhard (both Max-Planck-Institut für Extraterrestrische Physik, Garching, Germany).

The second team consists of S. Vásquez (Pontificia Universidad Católica de Chile, Santiago, Chile; ESO, Santiago, Chile), M. Zoccali (Pontificia Universidad Católica de Chile), V. Hill (Université de Nice Sophia-Antipolis, CNRS, Observatoire de la Côte d’Azur, Nice, France), A. Renzini (INAF − Osservatorio Astronomico di Padova, Italy; Observatoire de Paris, France), O. A. González (ESO, Santiago, Chile), E. Gardner (Université de Franche-Comté, Besançon, France), V. P. Debattista (University of Central Lancashire, Preston, UK), A. C. Robin (Université de Franche-Comté), M. Rejkuba (ESO, Garching, Germany), M. Baffico (Pontificia Universidad Católica de Chile), M. Monelli (Instituto de Astrofísica de Canarias & Universidad de La Laguna, La Laguna, Tenerife, Spain), V. Motta (Universidad de Valparaiso, Chile) and D. Minniti (Pontificia Universidad Católica de Chile; Vatican Observatory, Italy).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning the 39-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Links:

Research papers: Wegg et al and Vasquez et al.: http://www.eso.org/public/archives/releases/sciencepapers/eso1339/eso1339a.pdf and http://www.eso.org/public/archives/releases/sciencepapers/eso1339/eso1339b.pdf

MPE press release: http://www.mpe.mpg.de/3286155/News_20130912

Photos of VISTA: http://www.eso.org/public/images/archive/category/surveytelescopes/

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

Images, Text, Credits: ESO/NASA/JPL-Caltech/M. Kornmesser/R. Hurt/S. Brunier/VVV Survey/D. Minniti, I. Toledo/M. Zoccali/Videos: ESO/NASA/JPL-Caltech/M. Kornmesser/R. Hurt/University of Central Lancashire/V. Debattista (simulation)/L. Noel (animation)/ESO.

Best regards, Orbiter.ch

Comet Found Hiding in Plain Sight












NASA - Spitzer Space Telescope patch.

Sept 13, 2013

 Spitzer Spies a Comet Coma and Tail

Image above: With the help of NASA's Spitzer Space Telescope, astronomers have discovered that what was thought to be a large asteroid called Don Quixote is in fact a comet. Image Credit: NASA/JPL-Caltech/DLR/NAU.

For 30 years, a large near-Earth asteroid wandered its lone, intrepid path, passing before the scrutinizing eyes of scientists armed with telescopes while keeping something to itself. The object, known as Don Quixote, whose journey stretches to the orbit of Jupiter, now appears to be a comet.

The discovery resulted from an ongoing project coordinated by researchers at Northern Arizona University, Flagstaff, Ariz., using NASA's Spitzer Space Telescope. Through a lot of focused attention and a little luck, they found evidence of comet activity, which had evaded detection for three decades.

The results show that Don Quixote is not, in fact, a dead comet, as previously believed, but it has a faint coma and tail. In fact, this object, the third-biggest near-Earth asteroid known, skirts Earth with an erratic, extended orbit and is “sopping wet,” said David Trilling of Northern Arizona University, with large deposits of carbon dioxide and presumably water ice. Don Quixote is about 11 miles (18 kilometers) long.

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

“This discovery of carbon dioxide emission from Don Quixote required the sensitivity and infrared wavelengths of the Spitzer telescope and would not have been possible using telescopes on the ground,” said Michael Mommert, who conducted the research at the German Aerospace Center, Berlin, before moving to Northern Arizona University. This discovery implies that carbon dioxide and water ice might be present on other near-Earth asteroids, as well.

The implications have less to do with a potential impact, which is extremely unlikely in this case, and more with “the origins of water on Earth,” Trilling said. Impacts with comets like Don Quixote over geological time may be the source of at least some of it, and the amount on Don Quixote represents about 100 billion tons of water -- roughly the same amount that can be found in Lake Tahoe, Calif.

Mommert presented the results at the European Planetary Science Congress in London on Sept. 10.

Read the full news release from Northern Arizona University at http://news.nau.edu/nau-led-teams-discovers-comet-hiding-in-plain-sight/ .

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer 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 .

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

Greetings, Orbiter.ch

mercredi 11 septembre 2013

Long Drive Puts NASA Mars Rover Near Planned Waypoint












NASA - Mars Science Laboratory (MSL) patch.

Sept 11, 2013

 'Darwin' Outcrop at 'Waypoint 1' of Curiosity's trek to Mount Sharp

Image above: An outcrop visible as light-toned streaks in the lower center of this image has been chosen as a place for NASA's Mars rover Curiosity to study for a few days in September 2013. Image Credit: NASA/JPL-Caltech/MSSS.

NASA's Mars rover Curiosity now has a view of a patch of exposed bedrock scientists selected for a few days of close-up study, the first such study since the rover began its long trek to Mount Sharp two months ago.

Curiosity reached the crest of a rise informally called "Panorama Point."  From Panorama Point, the rover took photographs of a pale-toned outcrop area that the team chose earlier as "Waypoint 1" on the basis of imagery from NASA's Mars Reconnaissance Orbiter.

Five selected waypoints dot the mission's route southwestward from the "Glenelg" area, where Curiosity worked during the first half of 2013, and an entry point to the lower layers of Mount Sharp, the mission's next major destination.  Waypoint 1 lies about one-fifth of the way along the approximately 5.3-mile (8.6-kilometer) route, as plotted from examining orbiter images.

Curiosity advanced 464 feet (141.5 meters) on Sept. 5 in the longest one-day drive so far in the 13-month-old mission. The drive toward the elevated Panorama Point combined two segments. For a long initial segment, engineers chose the path from images examined on Earth ahead of time. That was followed by a 138-foot (42-meter) segment, for which the rover autonomously navigated its own path based on images taken during the day's drive. That Sept. 5 drive plus the next one -- 80 feet (24.3 meters) on Sept. 8 -- brought the rover to the top of Panorama Point.

For the Sept. 5 drive, "we had a long and unobstructed view of the hill we needed to climb, which would provide an overlook of the first major waypoint on our trek to Mount Sharp," said Jeff Biesiadecki, a rover planner on the Curiosity team at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We were able to extend the drive well beyond what we could see by enabling the rover's onboard hazard avoidance system."

Curiosity's View from 'Panorama Point' to 'Waypoint 1' and Outcrop 'Darwin'

Image above: NASA's Mars rover Curiosity captured this view using its Navigation Camera (Navcam) after reaching the top of a rise called "Panorama Point" with a drive during the 388th Martian day, or sol, of the rover's work on Mars (Sept. 8, 2013). Image Credit: NASA/JPL-Caltech.

In the Glenelg area, Curiosity accomplished the mission's major science goal by finding evidence of an ancient environment favorable for microbial life.  The evidence came from analysis of rock powder drilled from two outcrops in a shallow depression called "Yellowknife Bay." When the rover examines multiple rock layers of Mount Sharp, researchers hope to learn more about ancient habitable environments and major changes in environmental conditions.

"We want to know how the rocks at Yellowknife Bay are related to what we'll see at Mount Sharp," said the mission's project scientist, John Grotzinger of the California Institute of Technology, Pasadena. "That's what we intend to get from the waypoints between them. We'll use them to stitch together a timeline -- which layers are older, which are younger."

Mars Science Laboratory (MSL) "Curiosity". Image Credit: NASA/JPL-Caltech

The science team is using images taken from Panorama Point to select precisely where to pause for a few days and use instruments on Curiosity's arm to examine Waypoint 1. The rock targets being considered are still about 245 feet (75 meters) southwest of Curiosity's Sept. 9 position.

The trek to Mount Sharp will continue for many months after the planned work at Waypoint 1.

NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, manages the Mars Science Laboratory Project for NASA's Science Mission Directorate, Washington. JPL designed and built the project's Curiosity rover.

More information about Curiosity is online at http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl/ . You can follow the mission on Facebook at http://www.facebook.com/marscuriosity and on Twitter at http://www.twitter.com/marscuriosity .

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

Greetings, Orbiter.ch

Space Station Expedition 36 Turns to 37












ROSCOSMOS - Soyuz TMA-08M Mission patch.

11 September 2013

ESA astronaut Luca Parmitano, NASA astronaut Karen Nyberg and Russian cosmonaut Fyodor Yurchikhin waved goodbye to their crewmates as they left the International Space Station yesterday. This signals the end of Expedition 36 and the start of Expedition 37.

Cosmonaut Pavel Vinogradov together with flight engineers Chris Cassidy and Alexander Misurkin left the station in their Soyuz spacecraft and landed safely in Kazakhstan this morning.

Soyuz TMA-08M touchdown

The three astronauts left on the Station will continue working and maintaining the orbital outpost as they wait for the new arrivals to Expedition 37, Oleg Kotov, Sergei Ryazansky and Michael Hopkins, set to be launched on 25 September.

When their Soyuz ferry docks with the Station, Expedition 37 will be complete with six astronauts.

video
Last leg of the Journey

The change of Expeditions marks a halfway point for Luca’s busy and eventful mission. He monitored the docking of ESA’s Automated Transfer VehicleAlbert Einsteinand was responsible for unloading over 1400 items delivered by the supply ship. A second supply vessel, Japan’s HTV-4, left the Station last weekend.

Luca ventured outside to maintain and prepare the Station on two spacewalks in July. His second sortie was cut short when his helmet filled with water and he had to find his way back inside, without communications. His calm nerves, training and help from fellow astronauts and ground control saved the situation.

Luca spacewalker

Luca then put on his plumber’s hat and spent many hours replacing a failed pump in Europe’s Columbus laboratory module.

In addition to all this effort, Luca’s focus is on scientific research. He installed the new Fases experiment that is helping us to understand emulsions – small droplets suspended in liquids that are used in many industrial processes. Luca also upgraded ESA’s Biolab with a new microscope for future experiments.

Working on Biolab

Luca was a guinea pig for many experiments looking into how astronauts’ eyes and skin react to living in space, freezing samples for analysis back on Earth and filling in questionnaires on headaches.

Luca and his crewmates performed all these jobs and more while each exercising 1.5 hours a day. As they are only halfway through their mission, Luca, Karen and Fyodor have a lot more work facing them before their return to Earth on 10 November.

Last view of Earth

In his spare time, Luca is entertaining followers on Twitter with beautiful pictures of Earth. Follow their space adventure as it happens on Twitter, the Volare mission blog and Flickr.

Related links:

Luca on Twitter - @astro_luca: http://twitter.com/astro_luca

Luca on Flickr: http://www.flickr.com/volaremission

For information on the International Space Station, visit: http://www.nasa.gov/station

Images, Video, Text, Credits: ESA / NASA / B. Ingalls / ROSCOSMOS TV.

Best regards, Orbiter.ch

mardi 10 septembre 2013

Cluster shows plasmasphere interacting with Van Allen belts












ESA - Cluster II Mission patch.

10 September 2013

Near-Earth space is populated by charged particles - electrons and ions - which occupy regions known as the plasmasphere and the Van Allen radiation belts. Over the past decade, the four identical spacecraft of ESA's Cluster mission have made numerous studies of these regions, and a recent paper has revealed intriguing links between these overlapping regions.

video

Video above: Animation depicting how the outer boundary of the Earth's plasmasphere, the plasmapause, (shown in blue) and the two Van Allen radiation belts (shown in red) vary when the geomagnetic conditions change. Credit: ESA / C. Carreau.

The invisible bubble created by Earth's magnetic field – the magnetosphere – has been studied by space missions for more than half a century. One of the first scientific breakthroughs made by a spacecraft was the discovery of Earth's radiation belts in 1958. Two concentric, tyre-shaped belts of highly energetic (0.1–10 MeV) electrons and protons, which are trapped by the magnetic field and travel around the Earth, were revealed by an experiment on the Explorer 1 satellite. They were named after the instrument's lead scientist, James Van Allen.

The inner Van Allen belt is located typically between 6000 and 12 000 km (1 - 2 Earth radii [RE]) above Earth's surface, although it dips much closer over the South Atlantic Ocean. The outer radiation belt covers altitudes of approximately 25 000 to 45 000 km (4 to 7 RE). This belt is much more dynamic than the inner one, as it is readily affected by solar outbursts that impact the magnetosphere. At such times, its density can vary by several orders of magnitude.

Both belts are separated from each other by an empty "slot" region. A temporary third belt, between this slot and the outer main belt, was detected earlier this year by NASA's Van Allen Probes.

The Van Allen radiation belts partly overlap with the plasmasphere, a doughnut-shaped region of low energy charged particles (known as plasma) which co-rotates with the Earth. The cold plasma in the plasmasphere plays a crucial role in governing the dynamics of Earth's radiation belts. It does so by determining the growth and propagation of Very Low Frequency (VLF) radio waves, which are responsible for the energisation of the Van Allen radiation belts and particle loss in the belts through wave-particle interaction.

These two overlapping regions of near-Earth space have been studied many times in different ways by spacecraft. However, attempts to identify and explain how they interact have been hampered by the types of instruments flown and by the satellites' orbits. The relationship between the plasmasphere and the radiation belt boundaries is being continually investigated and much remains to be discovered.

An important new contribution has been made by an international team of physicists, led by Fabien Darrouzet, a researcher at the Belgian Institute for Space Aeronomy in Brussels. Their paper, published in the Journal of Geophysical Research, is based on data sent back by one of the quartet of Cluster spacecraft, which has been flying in formation around the Earth since 2000.

During the period 1 April 2007 to 31 March 2009, the Cluster flotilla penetrated deep inside the plasmasphere and the radiation belts, with a lowest orbital point of 2 RE. The team decided to take this rare opportunity to analyse populations of electrons of different energies in these regions with three of the instruments on board the Cluster satellite C3.

 Cluster satellites. Image credit: ESA

"We wanted to study the boundaries of the two regions – the plasmasphere and the radiation belts – with instruments on board the same satellite," explains Fabien Darrouzet. "Very precise complementary data could be collected at the same time and in the same place by using three different instruments on a single Cluster spacecraft."

The positions of the outer radiation belt's boundaries were deduced by analysing background data from the CIS instrument, which is sensitive to electrons with energy > 2 MeV, while the position of the plasmapause (the edge of the plasmasphere) was obtained from the WHISPER instrument, which is able to determine the electron density inside and outside the plasmasphere. These results were then refined by comparing them with data from the RAPID instrument, which determined the locations of the radiation belts' boundaries by detecting high energy electrons between 244 and 406 keV.

Several hundred data sets were obtained over the two year period of observation, which happened to coincide with a period of low solar activity and generally quiet geomagnetic conditions.
The team's analysis of the Cluster C3 observations showed more variety in the position of the outer edge of the plasmasphere – the plasmapause – than in the position of the furthest boundary of the outer radiation belt.


Image above: How geomagnetic conditions change the relative locations of the outer boundary of the Earth's plasmasphere (the plasmapause) and the Van Allen belts. Credit: ESA / C. Carreau.

For long periods, when geomagnetic activity was low, the plasmapause was located toward the farthest reaches of the outer belt – typically around 6 RE, but sometimes expanding outward to 8 RE or beyond. This result contrasted with previous studies based on other spacecraft observations, which indicated a correlation between the position of the inner edge of the outer belt and the position of the plasmapause.

However, there were indications of different behaviour during the occasional periods of higher geomagnetic activity. Then, the plasmapause moved closer to the inner boundary of the outer radiation belt, at around 4.5 RE, as observed by previous studies.

During the periods of low geomagnetic activity, the plasmasphere was more easily filled by material from the underlying ionosphere - Earth's highest atmospheric layer. During geomagnetic storms, however, the diameter of the plasmasphere was reduced and the plasmapause moved closer to Earth.
The thickness of the slot region, which separates the two main belts, was also found to follow the variations in geomagnetic activity. Particle loss in the radiation belts increased after the activity decreased and the plasmasphere expanded, causing the slot region to become wider.

"Having studied the plasmasphere and radiation belts during solar minimum, we are now intending to use Cluster data to study the links between both regions during periods of higher geomagnetic activity," says Fabien Darrouzet. "We would also like to study the wave-particle interactions in those two regions and learn more about how they influence the distribution of the particles when solar maximum occurs."

"The presence of the radiation belts is a key factor in the design of all spacecraft in low Earth orbit, as well as a natural hazard for astronauts," comments Philippe Escoubet, ESA Project Scientist for Cluster. "Forecasting the dynamics of the belts is one of our prime objectives, but this is only achievable by understanding the underlying physics."

"The Cluster mission offers the rare opportunity to analyse different regions of the inner magnetosphere with identical sensors on multiple spacecraft," he adds. "With the launch of NASA's Van Allen Probes in 2012, we look forward to an even more productive period of complementary scientific studies of near-Earth space."

Background Information

The results described in this article are reported in 'Links between the plasmapause and the radiation belt boundaries as observed by the instruments CIS, RAPID, and WHISPER onboard Cluster' by F. Darrouzet et al., published in the Journal of Geophysical Research: Space Physics, volume 118, pp 4176-4188, 2013, doi: 10.1002/jgra.50239.

The study team was led by Fabien Darrouzet (Belgian Institute for Space Aeronomy (IASB-BIRA), Brussels, Belgium) and included V. Pierrard (IASB-BIRA and Université Catholique de Louvain, Center for Space Radiations (CSR), Belgium), S. Bench (Université Catholique de Louvain, Center for Space Radiations (CSR), Belgium), G. Lointier (Laboratoire de Physique et Chimie de l'Environnement et de l'Espace, (LPC2E), Orléans, France), J. Cabrera (Université Catholique de Louvain, Center for Space Radiations (CSR), Belgium), K. Borremans (IASB-BIRA), N. Yu Ganushkina (Department of Atmospheric, Oceanic and Space Sciences (AOSS), University of Michigan, Ann Arbor, Michigan, USA and Finnish Meteorological Institute (FMI), Earth Observations, Helsinki, Finland.) and J. De Keyser (IASB-BIRA).

Cluster is a constellation of four spacecraft flying in formation around Earth. It is the first space mission able to study, in three dimensions, the natural physical processes occurring within and in the near vicinity of the Earth's magnetosphere. Launched in 2000, it is composed of four identical spacecraft orbiting the Earth in a pyramidal configuration, along a nominal polar orbit of 4 × 19.6 Earth radii (1 Earth radius = 6380 km). Cluster's payload consists of state-of-the-art plasma instrumentation to measure electric and magnetic fields over wide frequency ranges, and key physical parameters characterising electrons and ions from energies of near 0 eV to a few MeV. The science operations are coordinated by the Joint Science Operations Centre (JSOC) at the Rutherford Appleton Laboratory, United Kingdom, and implemented by ESA's European Space Operations Centre (ESOC), in Darmstadt, Germany.

Related Publications:

Darrouzet, F., et al. [2013]: http://sci.esa.int/cluster/object/index.cfm?fobjectid=52801

Related Link:
   
NASA's Van Allen Probes: http://www.nasa.gov/mission_pages/rbsp/main/index.html#.UhtK6Lxa_xQ

Images (mentioned), Video (mentioned), Text, Credits: ESA.

Best regards, Orbiter.ch

Gravity Lowdown









ESA - GOCE Mission logo.

10 September 2013

With a catalogue of triumphs that range from delivering novel information about winds at the edge of the atmosphere to mapping the structure of Earth’s crust 200 km below our feet, ESA’s GOCE satellite is in the limelight at this week’s Living Planet Symposium.

Carrying the first 3D gravity gradiometer in space and orbiting lower than any other research mission, this state-of-the-art satellite has measured Earth’s gravity with unprecedented accuracy, resulting in a series of four geoid models, each more accurate than the last.

video
 Gravity gradients within Earth’s lithosphere

And, a fifth is expected in the middle of next year that will include GOCE’s last measurements.

These final data will be even more accurate because they are being taken from an orbit 31 km lower than the satellite’s original mapping height – at the very limit of its capability but maximising its scientific return.

While the GOCE geoid is being used to understand how oceans transport huge quantities of heat around the planet and used to develop a global height reference system, the mission’s gravity-field measurements are also shedding new light on Earth’s interior.

Geophysicists are using GOCE gravity gradient measurements to gain, for example, new insights into the geodynamics associated with the lithosphere.

Jörg Ebbing from the Geological Survey of Norway said, “To understand the processes and dynamics of tectonic plate movement we need to know how the lithosphere is structured.

“Earth’s crust and the uppermost mantle form the lithospheric plates, which are moved by plate tectonics and mantle convection.”

Dr Ebbing went on to explain that there is a difference between oceanic and continental lithosphere.

Moho and lithosphere

“The oceanic lithosphere is young in geological terms, less than 200 million years old, and associated with sea-floor spreading and the widening of oceans. Continental lithosphere is older and thicker, and we know from seismology that it can be very heterogeneous in structure.

“However, a better understanding of the thermal structure and composition of the lithosphere is needed to understand, for instance, how mountain belts develop.”

Seismology as well as thermal and electromagnetic studies provide information about the lithosphere, but since variations in gravity reflect the inhomogeneous nature of Earth’s interior, accurate gravity data also prove invaluable.

Using GOCE measurements, the animation above shows gravity gradients from horizontal slices of the lithosphere at different depths under the northeast Atlantic region.

This area covers the warm young oceanic lithosphere under the Atlantic Ocean, the continental lithosphere beneath the Norwegian shelf and Scandinavian mountains, and the old thick lithosphere in the centre of the ‘Fennoscandian shield’.

The main gravity gradients are caused by variations in the thickness of the crust.

In addition, the high sensitivity to the depth of 150 km is shown. This depth, close to the crustal base, is poorly imaged in most seismological models.

GOCE session

“The use of GOCE gravity gradients is enabling us to distinguish whether crustal density is influenced by temperature or by the composition of the upper mantle,” said Dr Ebbing.

“This is giving us unprecedented detail on how the crust and upper mantle are linked.”

These new results complement other research that used GOCE data to produce the first high-resolution map of the depth of the Mohorovičić discontinuity, or Moho – the boundary between the crust and mantle.

The new findings go a step further than the classical Moho mapping by linking static geophysical imaging to dynamic processes inside the Earth.

While of huge scientific importance, results such as these are also of practical use. As the global population continues to grow, as does our need for natural resources stored in Earth’s crust. So better understanding its composition is likely to lead to more efficient exploration.

“Now that we have a procedure to use gravity gradients for geophysics, the community can look forward to the release of a global gravity gradient grids in 2014,” commented ESA’s Roger Haagmans.

Although GOCE will soon have completed its mission, new results continue to emerge as scientists find ever-more imaginative ways of using its data to further our knowledge of Earth.

As Prof. Reiner Rummel said, “GOCE offers a fresh look into Earth’s interior, in particular, when using the gravity gradients directly as now shown. The gradients provide, for the first time, a 3D image of Earth from gravity.”

Related links:

Conference site: http://www.livingplanet2013.org/index.asp

ESA Earth Observation: http://www.esa.int/Our_Activities/Observing_the_Earth

GOCE: http://www.esa.int/Our_Activities/Observing_the_Earth/GOCE

Support to Science Element GOCE+ GeoExplore: http://goce4interior.dgfi.badw.de/

Geological Survey of Norway: http://www.esa.int/Our_Activities/Observing_the_Earth/Living_Planet_Symposium_2013/www.ngu.no

German Geodetic Research Institute: http://www.dgfi.badw.de/index.php?id=2&L=0

Institute for Astronomical and Physical Geodesy TUM: http://www.iapg.bv.tum.de/iapg_en.html

Images, Video, Text, Credits: ESA / M. Cochrane / GeoExplore STSE GOCE+ study team.

Greetings, Orbiter.ch

lundi 9 septembre 2013

Hubble Catches a Spiral in the Air Pump












NASA - Hubble Space Telescope patch.

Sept. 9, 2013

 Hubble Catches a Spiral in the Air Pump

Lying more than 110 million light-years away from Earth in the constellation of Antlia (The Air Pump) is the spiral galaxy IC 2560, shown here in an image from NASA/ESA Hubble Space Telescope. At this distance it is a relatively nearby spiral galaxy, and is part of the Antlia cluster — a group of over 200 galaxies held together by gravity. This cluster is unusual; unlike most other galaxy clusters, it appears to have no dominant galaxy within it.

In this image, it is easy to spot IC 2560's spiral arms and barred structure. This spiral is what astronomers call a Seyfert-2 galaxy, a kind of spiral galaxy characterized by an extremely bright nucleus and very strong emission lines from certain elements — hydrogen, helium, nitrogen, and oxygen. The bright center of the galaxy is thought to be caused by the ejection of huge amounts of super-hot gas from the region around a central black hole.

Hubble Space Telescope

There is a story behind the naming of this quirky constellation — Antlia was originally named antlia pneumatica by French astronomer Abbé Nicolas Louis de Lacaille, in honor of the invention of the air pump in the 17th century.

For more information about Hubble Space Telescope, visit: http://www.spacetelescope.org/ and http://hubblesite.org/

Images, Text, Credits: Hubble / European Space Agency and NASA.

Cheers, Orbiter.ch

dimanche 8 septembre 2013

Crew Exchange, New Cargo Ship Awaits Station














ISS - Expedition 36 Mission patch / JAXA - H-II Transfer Vehicle HTV-4 patch.

Sept 8, 2013

Three Expedition 36 crew members are preparing for their return home Tuesday night. A Japanese cargo craft that left the International Space Station on Wednesday will deorbit Saturday morning over the Pacific Ocean. Meanwhile, the six-member station crew continues its focus on international science and maintenance while exercising to counter the effects of long-duration microgravity.

Commander Pavel Vinogradov and Flight Engineers Chris Cassidy and Alexander Misurkin finalized their Soyuz descent training Friday. They are scheduled to land in their Soyuz TMA-08M Tuesday at 10:59 p.m. EDT (8:59 a.m. Wednesday Kazakhstan time).

Vinogradov will ceremonially hand over control of the station to Flight Engineer Fyodor Yurchikhin at 2:25 p.m. Monday in a traditional Change of Command Ceremony. When Expedition 36 undocks, Yurchikhin will officially become Expedition 37 commander staying behind with Flight Engineers Karen Nyberg and Luca Parmitano. The station residents staying behind reviewed their emergency roles and responsibilities during the upcoming crew exchange.

Luca Parmitano photographed HTV-4 departure. Image credit: NASA

As the station says goodbye to two vehicles and a departing trio, a new cargo craft and a new crew are being readied for launches this month. Orbital Sciences is preparing its Cygnus commercial cargo craft for a Sept. 17 demonstration mission to the station. In Russia, Expedition 37/38 crew members Oleg Kotov, Mike Hopkins and Sergey Ryazanskiy are counting down to their Sept. 25 launch.

Read more about Orbital Sciences: http://www.nasa.gov/exploration/commercial/cargo/orbitalsciences-index.html

A variety of science is taking place on the orbital laboratory sponsored by both public and commercial organizations. Microgravity science takes advantage of the weightless environment for research not possible on Earth to improve life and expand knowledge.


Image above: Luca Parmitano works inside the Destiny laboratory with Karen Nyberg (background) working inside the Unity node. Image Credit: NASA TV.

Cassidy, photographed samples collected for the BCAT-C1 (Binary Colloidal Alloy Test) experiment. That study observes nano-particles dispersed in liquids with potential benefits for different industries such as foods and electronics. Nyberg joined Parmitano for spinal scans using ultrasound and electrocardiogram gear. The scanning data is downlinked real-time to Earth for study by medical investigators.

Read more about BCAT-C1: http://www.nasa.gov/mission_pages/station/research/experiments/649.html

Read more about Ultrasound-2: http://www.nasa.gov/mission_pages/station/research/experiments/749.html


Image above: Japan's H-II Transfer Vehicle orbits Earth after being released from the International Space Station. Image Credit: NASA.

Japan’s H-II Transfer Vehicle “Kounotori-4” is poised to reenter Earth’s atmosphere Saturday ending a month long stay in space. In anticipation of the Kounotori-4’s fiery descent over the Pacific Ocean, Cassidy set up three cameras inside the cupola to capture the event.

Station Releases a White Stork and Awaits a Swan

The Expedition 36 crew released Japan’s H-II Transfer Vehicle-4 (HTV-4) cargo craft Wednesday at 12:20 p.m. EDT ending its one-month stay at the International Space Station.  Expedition 36 Flight Engineer Karen Nyberg, operating from the station’s cupola robotics work station, used the Canadarm2 to release the cargo craft. Robotic ground controllers at Mission Control, Houston unberthed the HTV-4 from the Earth-facing port of the Harmony module at 8:07 a.m.


Image above: The Canadarm2 prepares to release Japan's H-II Transfer Vehicle-4. Image Credit: NASA TV.

HTV-4 will maneuver to a safe distance away from the station where it will be commanded by Japanese flight controllers to deorbit on Saturday, Sept. 7. The craft, now loaded with trash, will burn up as it reenters the Earth’s atmosphere over the Pacific Ocean.

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

Images (mentioned), Text, Credit: NASA.

Greetings, Orbiter.ch