samedi 7 avril 2012

ExoMars project: agreement for between Europe and Russia

ESA / ROSCOSMOS - ExoMars Mission logo.

March 7, 2012

The European Space Agency (ESA) and the Russian Space Agency (Roskosmos) will sign the end of 2012 an agreement on Russian participation in the project ExoMars Mars exploration, the U.S. has recently abandoned, Roskosmos said Friday.

This decision was made Friday during a meeting in Moscow between the head of Roskosmos, Vladimir Popovkin, and that of ESA, Jean-Jacques Dordain, according to a statement of the Russian agency.

"One theme of the meeting was the possibility that Russia participates in the project (...) ExoMars," the statement said.

ESA - ExoMars poster

"The parties agreed that the project was feasible and common scientific interest. It was decided (...) to prepare a formal agreement to be signed by end-2012, "he says, without elaborating.

Developed by ESA in cooperation with the U.S. space agency (Nasa), the ExoMars program provides for sending two probes to Mars - the first in 2016 and the second in 2018 - to execute various drilling Martian soil and return samples to Earth in the early 2020s.

But in February, NASA announced it was abandoning the project, the White House had decided in 2013 to reduce the budget for the robotic exploration of Mars.

In November, Russia suffered a serious setback in the sending of a Mars probe, Phobos-Grunt, which failed to break free of gravity. This mission was the first interplanetary expedition of the country since 1986.

Image, Text, Credits: ESA / AFP / Translation:


DAN - neutron "lozohod" (MSL instrument)

ROSCOSMOS logo / NASA - Mars Science Laboratory (MSL) patch.


With the Russian device, DAN, who is flying to Mars aboard the American interplanetary station, produced the first scientific information. DAN, made at the Institute for Space Studies, stands for "dynamic neutron albedo." Its main task - with the help of the reflected beam of particles to determine how much water is in the soil of the Red Planet. We can say - neutron lozohod.

Russian scientists have tested their equipment installed on the Mars Science Laboratory, which was sent to the Red Planet four months ago. Detection of albedo neutrons or abbreviated as "DAN" defective. Neither the start nor the space the way millions of kilometers he was not hurt.

"The unit was half way to Mars, about 60 million miles, and on this cut-off was decided, it will advance mortgage, you need to enable devices to see whether all the instruments were alive," - says Maxim Mokrousov, a leading developer of hardware DAN.

MSL Curiosity Rover science instruments

Station "Kyuriositi" in Russian - "Curiosity", will arrive on the red planet in August, and landed in a crater near the equator Gale. The diameter of the crater 150 kilometers, according to scientists, it was formed after the fall of a meteorite three billion years ago. This is one of the deepest craters on Mars. And perhaps he had once been filled with water. It is the instrument DAN should confirm or refute this hypothesis.

"In the scientific community for a long time discussing where to sit, selected Gale Crater. There, the water can be, and minerals, and soil composition of interest "- continues Maxim Mokrousov.

DAN instrument consists of two blocks. One - neutron generator. Second - on-board microcomputer. While the rover "Curiosity" will go all over the crater, DAN neutron beams will be shot on the meter-deep Martian surface.

"Neutrons are not that strike, they penetrate to a depth of one meter, they walk, walk, and then come to the surface, then we do exactly that Merimee block. The more water in the soil, the fewer neutrons at the exit "- continues to tell Maxim Mokrousov.

In a project to investigate the Red Planet 5 countries involved. Russian scientists from the Institute for Space Studies was invited to American counterparts. Following a joint experiment on the moon three years ago. Then the Russian instrument "Land" established by the American satellite, was looking for ice. Studies have shown that the moon is not a boulder, there - large deposits of ice in the so-called "cold traps".

According to the head of the laboratory space gamma-ray spectroscopy of Igor Mitrofanov ISR data the ice must be in the so-called dark traps, where no sunlight penetrates.

Now experts determine which areas of the Moon and Mars, more water, which is very important for future outpost bases.

Original text in Russian:

Image, Text, Credits: ROSCOSMOS / TV Studio Space Agency / NASA / JPL / Translation:


jeudi 5 avril 2012

NASA Extends Kepler, Spitzer, Planck Missions

NASA - Kepler Mission patch / NASA - Spitzer Space Telescope patch / ESA - NASA Plank logo.

March 5, 2012

NASA is extending three missions affiliated with the Jet Propulsion Laboratory in Pasadena, Calif. -- Kepler, the Spitzer Space Telescope and the U.S. portion of the European Space Agency's Planck mission -- as a result of the 2012 Senior Review of Astrophysics Missions.

The 2012 NASA Senior Review report, which includes these three missions and six others also being extended, is available at: .

"This means scientists can continue using the three spacecraft to study everything from the birth of the universe with Planck, and galaxies, stars, planets, comets and asteroids with Spitzer, while Kepler is determining what percentage of sun-like stars host potentially habitable Earth-like planets," said Michael Werner, the chief scientist for astronomy and physics at JPL.

Kepler has been approved for extension through fiscal year 2016, which ends Sept. 30, 2016. All fiscal year 2015 and 2016 decisions are for planning purposes and will be revisited in the 2014 Senior Review. The extension provides four additional years to find Earth-size planets in the habitable zone -- the region in a planetary system where liquid water could exist on the surface of the orbiting planet -- around sun-like stars in our galaxy.

Spitzer, launched in 2003, continues to provide the astronomical community with its unique infrared images. It has continued to explore the cosmos since running out of coolant, as expected, in 2009. Among its many duties during its warm mission, the observatory is probing the atmospheres of planets beyond our sun and investigating the glow of some of the most distant galaxies known. As requested by the project, Spitzer received two additional years of operations. Like other NASA missions, the Spitzer team will be able to apply for a further extension in 2014.

Image above: From left to right, artist's concepts of the Spitzer, Planck and Kepler space telescopes. NASA extended Spitzer and Kepler for two additional years; and the U.S. portion of Planck, a European Space Agency mission, for one year. The relative sizes of the artist's concepts are not to scale. Image credit: NASA / JPL-Caltech.

NASA will fund one additional year of U.S. participation in the European Space Agency's Planck mission, for the U.S. Planck data center and for operations of Planck's Low Frequency Instrument. Planck, launched in 2009, is gathering data from the very early universe, shortly after its explosive birth in a big bang. Planck's observations are yielding insight into the origin, evolution and fate of our universe. The U.S. Planck team will apply for additional funding after a third data release has been approved by the European consortiums.

Ames Research Center, Moffett Field, Calif., manages Kepler's ground system development, mission operations and science data analysis. JPL managed the Kepler mission's development. Ball Aerospace & Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. The Space Telescope Science Institute in Baltimore archives, hosts and distributes Kepler science data. Kepler is NASA's 10th Discovery mission and is funded by NASA's Science Mission Directorate at the agency's headquarters in Washington. For more information about the Kepler mission, visit: and .

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

Planck is a European Space Agency mission, with significant participation from NASA. NASA's Planck Project Office is based at JPL. JPL contributed mission-enabling technology for both of Planck's science instruments. European, Canadian and U.S. Planck scientists will work together to analyze the Planck data. More information is online at: and .

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

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

Best regards,

The pit-chains of Mars – a possible place for life?

ESA - Mars Express Mission patch.

5 April 2012

 Pit-chains in Tharsis

The latest images released from ESA’s Mars Express reveal a series of ‘pit-chains’ on the flanks of one of the largest volcanoes in the Solar System. Depending on their origin, they might be tempting targets in the search for microbial life on the Red Planet.

The images, taken on 22 June 2011, cover Tractus Catena in the Arcadia quadrangle, part of the vast Tharsis region on Mars. This region boasts a number of huge volcanoes, including the three collectively known as Tharsis Montes. To their north sits Alba Mons, also known as Alba Patera, one of the largest volcanoes in the Solar System by area and volume.

Tractus Catena sits on its southeastern flank of Alba Mons and the pit-chains in that region are a series of circular depressions that formed along fracture points in the martian crust.

Pit-chains can have a volcanic origin. Lava streaming from a volcano solidifies on the surface, leaving a molten tube of lava running below. 

Tractus Catena region

Once volcanic activity ceases, the tube empties, leaving behind a subterranean cavity. Over time, parts of the roof over the cavity may collapse, leaving circular depressions on the surface. On Earth, recent examples can be seen on the flanks of Kilauea volcano in Hawaii, while on the Moon, Hadley Rille, visited by Apollo 15 in 1971, is believed to have formed in the same way billions of years ago.

Pit-chains at high resolution

Pit-chains can also be caused by strains in the Martian crust, which translates into a series of parallel elongated depressions known as grabens, in which pits can also form.

But the most dramatic scenario involves groundwater. On Earth, there are clear examples of similar structures in ‘Karst’ regions – after the German name for a region extending from Slovenia to Italy, where this phenomenon was first studied.

Some of Earth’s most famous examples are the network of ‘cenotes’ on the Yucatan peninsula of Mexico. These deep natural pits form when the surface limestone rocks collapse, exposing the groundwater underneath.

This origin is the most interesting in the context of the search for microbial life on Mars. If there are any cave-like structures associated with the pits, microorganisms could have survived, protected from the harsh surface environment.

Map of the pit-chains

Mars landers have measured surface radiation around 250 times higher than that found on the Earth, and more than double that experienced by astronauts on board the International Space Station. Any caves associates with the pit-chains may in future provide a possible refuge for astronauts from the harsh surface radiation.

However they formed, these pit-chains show again just how similar many of the geological processes on Mars are to those on the Earth, and provide interesting targets for future missions.

Tractus Catena pit-chains
Pit-chains in 3D

Related links:

High Resolution Stereo Camera:

Behind the lens:

Frequently asked questions:

For specialists:

ESA Planetary Science archive (PSA):

NASA Planetary Data System:

HRSC data viewer:

Images, Text, Credits: ESA / DLR / FU Berlin (G. Neukum).


A magnetic surprise for Venus Express

ESA - Venus Express Mission patch.

05 Apr 2012

Venus is a rarity among planets - a world that does not internally generate a magnetic field. Despite the absence of a large protective magnetosphere, the near-Venus environment does exhibit a number of similarities with planets such as Earth. The latest, surprising, example is the evidence for magnetic reconnection in Venus' induced magnetotail.

Solar wind shaping the magnetospheres of Earth and Venus. Credit: ESA

Planets which generate magnetic fields in their interiors, such as Earth, Mercury, Jupiter and Saturn, are surrounded by invisible magnetospheres. Their magnetic fields deflect the charged particles of the solar wind (electrons and protons) as they stream away from the Sun. This deflection creates a magnetosphere - a protective "bubble" around the planet - which ends in an elongated magnetotail on the lee side of the magnetosphere.

Since Venus has no intrinsic magnetic field to act as a shield against incoming charged particles, the solar wind sometimes interacts directly with the upper atmosphere. However, Venus is partially protected by an induced magnetic field.

As on Earth, solar ultraviolet radiation removes electrons from the atoms and molecules in the upper atmosphere, creating a region of electrically charged gas known as the ionosphere. This ionised layer interacts with the solar wind and the magnetic field carried by the solar wind.

During the continuous battle with the solar wind, this region of the upper atmosphere is able to slow and divert the flow of particles around the planet, creating a magnetosphere, shaped rather like a comet's tail, on the lee side of the planet

Spacecraft observations over many decades have shown that magnetic reconnection occurs frequently in the magnetospheres of Earth, Mercury, Jupiter and Saturn. This process, which converts magnetic energy into kinetic energy, occurs when oppositely directed magnetic field lines break and reconnect with each other. On Earth, this reconnection is responsible for magnetic storms and polar auroras - the so-called Northern and Southern Lights.

Video above: Animation of magnetic reconnection in Venus' induced magnetotail. Credit: ESA.

Until now, reconnection was not generally thought to occur on non-magnetised planets. However, Tielong Zhang and an international team of co-authors now report on Science Express, the online version of the journal Science, that they have found the first evidence of magnetic reconnection in Venus' magnetotail.

ESA's Venus Express spacecraft follows a near-polar orbit which is ideal for instruments such as the magnetometer and low-energy particle detector to observe the solar wind - ionosphere - magnetotail interaction. Previous missions, such as Pioneer Venus, have either been in different orbits or been active at different periods of solar activity, so they not been able to detect these reconnection events.

Venus Express. Credit: ESA

On 15 May 2006, Venus Express was crossing the Venusian magnetotail when it observed a rotational magnetic field structure over a period of about 3 minutes. Calculations based on its duration and speed imply that it was about 3400 km across.

The event, which took place about 1.5 Venus radii (about 9000 km) down the tail, is thought to be evidence of a passing plasmoid - a transient magnetic loop structure which is formed by magnetic reconnection in a planetary magnetotail.

Further studies of the magnetic field data from Venus Express revealed the signatures of many similar observations of energy exchange between the magnetic field and the plasma in the tail.

The data also show that, in many respects, the magnetosphere of Venus is a scaled-down version of Earth's.

Magnetic reconnection occurs in the Earth's magnetotail and plasma sheet at a distance of about 10-30 planetary radii down the magnetotail. Since Earth's magnetosphere is 10 times larger, reconnection at Venus would be expected to occur 1-3 radii down its tail. That is exactly where Venus Express detected the reconnection events.

"Plasmoids are common features in the magnetospheres of planets such as Earth and Jupiter, but they were not expected in the magnetotail of an unmagnetised planet such as Venus," said Tielong Zhang, lead author of the Science paper. Zhang is Principal Investigator for the magnetometer instrument on Venus Express and a Senior Research Scientist at the Space Research Institute in Graz, Austria.

"The reconnection splits the magnetotail, causing most of the plasma in the tail to be ejected into space. It also forms a plasmoid structure which heads towards Venus and channels a fraction of the energy flux of the solar wind into the night-side atmosphere. As a result, the magnetic reconnection causes plasma circulation at Venus, similar to what happens in Earth's magnetotail."

The discovery that plasma is lost from the tail as a result of magnetic reconnections provides a possible new mechanism for explaining how and why gases are lost from Venus's upper atmosphere. This has implications for understanding how Venus lost its water after the planet began to experience a runaway greenhouse effect.

"Although the understanding of atmospheric loss is a key to establishing the evolutionary history of planets, the role of magnetic reconnection is still poorly understood because of the scarcity of in situ observations at planets other than Earth," said Håkan Svedhem, ESA's Venus Express Project Scientist.

"This result confirms that observation of the terrestrial planets by spacecraft such as Venus Express, Mars Express and Cluster is essential if we are to understand the complex evolution of atmospheres and planets in general."

Related publication:

Zhang, T. L., et al., "Magnetic Reconnection in the Near Venusian Magnetotail", Science 1217013 Published online 5 April 2012, doi:10.1126/science.1217013

Notes for editors:

The study presented here is based on measurements obtained with the Magnetometer (MAG) and Analyser of Space Plasmas and Energetic Atoms (ASPERA-4) instruments on board ESA's Venus Express spacecraft.

The MAG magnetometer measures the strength and direction of the induced magnetic field that is found around Venus. This information is used to identify boundaries between the various plasma regions, study the interaction of the solar wind with the atmosphere of Venus and provide support data for measurements made by other instruments.

The ASPERA-4 experiment is designed to study the interaction between the solar-wind and the Venusian atmosphere, and to characterise the plasma and neutral-gas environment in near-Venus space through the imaging of energetic neutral atoms and local charged particle measurements.

Venus Express, Europe's first mission to Earth's twin world, is investigating the nature of our closest planetary neighbour. Launched from the Baikonur Cosmodrome in Kazakhstan on 9 November 2005 upon a Soyuz-Fregat launcher, it was inserted into Venus orbit on 11 April 2006, and is currently the only spacecraft in orbit around the planet.

For more informations about Venus Express Mission, visit:

Image (mentioned), Anomation (mentioned), Text, Credits: ESA / Space Research Institute Austrian Academy of Sciences, Tielong Zhang / ESA Venus Express Project Scientist / Research and Scientific Support / Department Science and Robotic Exploration Directorate / Håkan Svedhem.


12-Mile-High Martian Dust Devil Caught in Act

NASA - Mars Reconnaissance Orbiter (MRO) patch.

March 5, 2012

Video above: Animation of a skinny "dust devil" on the dust-covered Amazonis Planitia region of northern Mars.

A Martian dust devil roughly 12 miles high (20 kilometers) was captured whirling its way along the Amazonis Planitia region of Northern Mars on March 14. It was imaged by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. Despite its height, the plume is little more than three-quarters of a football field wide (70 yards, or 70 meters).

Dust devils occur on Earth as well as on Mars. They are spinning columns of air, made visible by the dust they pull off the ground. Unlike a tornado, a dust devil typically forms on a clear day when the ground is heated by the sun, warming the air just above the ground. As heated air near the surface rises quickly through a small pocket of cooler air above it, the air may begin to rotate, if conditions are just right.

The image was taken during late northern spring, two weeks short of the northern summer solstice, a time when the ground in the northern mid-latitudes is being heated most strongly by the sun.

Image above: A Martian dust devil roughly 12 miles (20 kilometers) high was captured winding its way along the Amazonis Planitia region of Northern Mars on March 14, 2012 by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. Image credit: NASA / JPL-Caltech / UA.

The Mars Reconnaissance Orbiter has been examining the Red Planet with six science instruments since 2006. Now in an extended mission, the orbiter continues to provide insights into the planet's ancient environments and how processes such as wind, meteorite impacts and seasonal frosts continue to affect the Martian surface today. This mission has returned more data about Mars than all other orbital and surface missions combined.

Mars Reconnaissance Orbiter

More than 21,700 images taken by HiRISE are available for viewing on the instrument team's website: . Each observation by this telescopic camera covers several square miles, or square kilometers, and can reveal features as small as a desk.

HiRISE is operated by the University of Arizona, Tucson. The instrument was built by Ball Aerospace & Technologies Corp., Boulder, Colo. The Mars Reconnaissance Orbiter Project and the Mars Exploration Rover Project are managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Science Mission Directorate, Washington. JPL is a division of the California Institute of Technology in Pasadena. Lockheed Martin Space Systems, Denver, built the orbiter.

For more information about the Mars Reconnaissance Orbiter, see

Image (mentioned), Animation, Text, Credits: NASA / Jet Propulsion Laboratory / DC Agle / University of Arizona.

Best regards,

Satellite observes rapid ice shelf disintegration in Antarctic

ESA - ENVISAT Mission logo.

5 April 2012

As ESA’s Envisat satellite marks ten years in orbit, it continues to observe the rapid retreat of one of Antarctica’s ice shelves due to climate warming.

One of the satellite’s first observations following its launch on 1 March 2002 was of break-up of a main section of the Larsen B ice shelf in Antarctica – when 3200 sq km of ice disintegrated within a few days due to mechanical instabilities of the ice masses triggered by climate warming.

Now, with ten years of observations using its Advanced Synthetic Aperture Radar (ASAR), Envisat has mapped an additional loss in Larsen B’s area of 1790 sq km over the past decade. 

Larsen B: 2002-2012

The Larsen Ice Shelf is a series of three shelves – A (the smallest), B and C (the largest) – that extend from north to south along the eastern side of the Antarctic Peninsula.

Larsen A disintegrated in January 1995. Larsen C so far has been stable in area, but satellite observations have shown thinning and an increasing duration of melt events in summer.

“Ice shelves are sensitive to atmospheric warming and to changes in ocean currents and temperatures,” said Prof. Helmut Rott from the University of Innsbruck.

Larsen Ice Shelf in 2012

“The northern Antarctic Peninsula has been subject to atmospheric warming of about 2.5°C over the last 50 years – a much stronger warming trend than on global average, causing retreat and disintegration of ice shelves.”

Larsen B decreased in area from 11512 sq km in early January 1995 to 6664 sq km in February 2002 due to several calving events. The disintegration in March 2002 left behind only 3463 sq km. Today, Envisat shows that only 1670 sq km remain.

Envisat has already doubled its planned lifetime, but is scheduled to continue observations of Earth’s ice caps, land, oceans and atmosphere for at least another two years.


This ensures the continuity of crucial Earth-observation data until the next generation of satellites – the Sentinels – begin operations in 2013.

“Long-term systematic observations are of particular importance for understanding and modelling cryospheric processes in order to advance the predictive capabilities on the response of snow and ice to climate change,” said Prof. Rott.

“Climate models are predicting drastic warming for high latitudes. The Envisat observations of the Larsen Ice Shelf confirm the vulnerability of ice shelves to climatic warming and demonstrate the importance of ice shelves for the stability of glaciers upstream.

Larsen B: 1992-2002

“These observations are very relevant for estimating the future behaviour of the much larger ice masses of West Antarctica if warming spreads further south.”

Radars on Earth observation satellites, such as Envisat’s ASAR, are particularly useful for monitoring polar regions because they can acquire images through clouds and darkness.

The Sentinel missions – being developed as part of Europe’s Global Monitoring for Environment and Security (GMES) programme – will continue the legacy of radar observations.

Related links:

Envisat's 10th birthday:


Space for our climate:

Images, Animation, Text, Credits: ESA / ENVEO.


mercredi 4 avril 2012

The dark heart of a cosmic collision

ESA - XMM-Newton Mission patch / ESA - Herschel Mission patch.

4 April 2012

 Centaurus A: Far-infrared and X-rays

Two of ESA’s space observatories have combined to create a multi-wavelength view of violent events taking place within the giant galaxy of Centaurus A. The new observations strengthen the view that it may have been created by the cataclysmic collision of two older galaxies.

Centaurus A is the closest giant elliptical galaxy to Earth, at a distance of around 12 million light-years. It stands out for harbouring a massive black hole at its core and emitting intense blasts of radio waves. 

While previous images taken in visible light have hinted at a complex inner structure in Centaurus A, combining the output of two of ESA’s observatories working at almost opposite ends of the electromagnetic spectrum reveals the unusual structure in much greater detail.

Centaurus A: Visible light

The galaxy was notably observed by Sir John Herschel in 1847 during his survey of the southern skies. Now, over 160 years later, the observatory bearing his family name has played a unique role in uncovering some of its secrets.

New images taken with the Herschel space observatory with unprecedented resolution at far-infrared wavelengths show that the giant black scar of obscuring dust crossing the centre of Centaurus A all but disappears.

Multi wavelength video of Centaurus A

The images show the flattened inner disc of a spiral galaxy the shape of which scientists believe is due to a collision with an elliptical galaxy during some distant, past epoch.

The Herschel data also uncover evidence for intense star birth towards the centre of the galaxy along with two jets emanating from the galaxy’s core – one of them 15 000 light-years long. Newly-discovered clouds co-aligned with the jets can also be seen in the far-infrared.

Centaurus A: Far-infrared

“The sensitivity of the Herschel observations enables us to see not only the glow from dust in and around the galaxy, but also emission from electrons in the jets spiralling in magnetic fields at velocities close to the speed of light,” explains Göran Pilbratt, Herschel Project Scientist.

ESA’s XMM-Newton X-ray observatory recorded the high-energy glow from one of the jets, extending over 12 000 light years away from the galaxy’s bright nucleus.

Centaurus A: X-rays

XMM-Newton’s X-ray view shows not only the way that the jet interacts with the surrounding interstellar matter, but also the galaxy’s intensely active nucleus, and its large gaseous halo.

“XMM-Newton is well suited to detecting extended weak X-ray emission, often allowing us to see halos around galaxies for the first time,” notes Norbert Schartel, XMM-Newton Project Scientist.

The jets seen by both satellites are evidence of the supermassive black hole – ten million times the mass of our Sun – at the centre of the galaxy.

Component images

This unique collaboration, alongside observations from the ground in visible light, has given us a new perspective on the drama in objects like Centaurus A, with a black hole, star birth, and the clashing of two distinct galaxies all rolled in to one.
More information:

Herschel overview:

XMM-Newton overview:

ISO overview:

Online Showcase of Herschel Images OSHI:

Images, Animation, Text, Credits: Far-infrared: ESA/Herschel/PACS/SPIRE/C.D. Wilson, MacMaster University, Canada; X-ray: ESA/XMM-Newton/EPIC/ESO/MPG 2.2-m telescope on La Silla.


ESA and NASA join forces to measure Arctic sea ice

ESA - Cryosat 2 Mission logo / NASA - Operation IceBridge patch.

4 April 2012

Marking another remarkable collaborative effort, ESA and NASA met up over the Arctic Ocean this week to perform some carefully coordinated flights directly under CryoSat orbiting above. The data gathered help ensure the accuracy of ESA’s ice mission.

The aim of this large-scale campaign was to record sea-ice thickness and conditions of the ice exactly along the line traced by ESA’s CryoSat satellite orbiting high above. A range of sensors installed on the different aircraft was used to gather complementary information.

Arctic sea ice from the NASA P-3

These airborne instruments included simple cameras to get a visual record of the sea ice, laser scanners to clearly map the height of the ice, an ice-thickness sensor called EM-Bird along with ESA’s sophisticated radar altimeter called ASIRAS and NASA’s snow and Ku-band radars, which mimic CryoSat’s measurements but at a higher resolution. 

In orbit for two years, CryoSat carries the first radar altimeter of its kind to monitor changes in the thickness of ice.

Perfectly coordinated flight paths

As with any Earth observation mission, it is important to validate the readings acquired from space. This involves comparing the satellite data with measurements taken in situ, usually on the ground and from the air.

The teams of scientists from Europe, US and Canada expect that by pooling flight time and the results they will get a much-improved accuracy of global ice-thickness trends measured by CryoSat and NASA’s IceSat.

This will, in turn, lead to a better understanding of the impact of climate change on the Arctic environment.

Off to rendezvous with NASA

Rene Forsberg, from the Technical University of Denmark’s National Space Institute, said, “As a scientist I value the collaboration very much.

“Data from a particular instrument provides one piece of the puzzle. Through experience in combining gravity and altimetry measurements over ice sheets, I’ve found that by combining measurements from different instruments you can solve the puzzle more easily and move forward.”

Coordinated campaign activities in these extremely cold and remote locations are difficult and include numerous challenges. The most obvious is the extreme weather. While much of Europe and North America is now enjoying the spring weather, temperatures in the high Arctic still often dip below –30° C.

Sea ice from laser scanner

These cold temperatures present challenges in running the aircraft and the complex scientific instruments on board, and of course, for the participants.

Distance and time zones are another challenge, because the NASA team is located in Thule, Greenland, and the ESA team is in Alert, Canada. Last, but not least, ESA’s satellite operations, such as orbit manoeuvres and instrument settings, need to be coordinated with field activities to maximise the scientific return.

Mosaic of sea ice

Despite these and many other challenges, the joint flights proved a resounding success.

On two occasions during the past week as the CryoSat satellite came over the horizon on the other side of the Arctic Ocean and raced across the frozen sea at over 6 km/second, the ESA and NASA planes met up along the coast and headed out over the frozen water within metres of each other to follow the line traced by CryoSat.

NASA’s Icebridge Project Scientist, Michael Studinger, said, “The joint ESA/NASA campaign has been incredibly successful again.

Profile of sea ice and snow cover

“It would be easy to view such a success as ordinary and lose sight of how difficult this whole undertaking really is. The skill and experience of all teams involved is the foundation for safety of operations and success in such an extreme environment.”

Malcolm Davidson, ESA's CryoSat Validation Manager, added, “By joining forces and pooling their efforts, ESA and NASA are able to achieve much more than each agency would separately.

“The joint activities this week provide a vivid illustration of the many synergies that such a collaboration brings.”

Related links:

NASA Operation Icebridge:

NASA Icebridge blog:

Technical University of Denmark-National Space Institute:

DTU Sea-ice:

Alfred Wegener Institute:


Access CryoSat data:

Images, Animation, Text, Credits: ESA/DTU Space/R. Saldo/M. Davidson/NASA/M. Studinger/E. Fraim/DTU Space/H. Skourup/CReSIS Team/The University of Kansas.


mardi 3 avril 2012

Busy first days for ATV Edoardo Amaldi

ESA - ATV-3 Edoardo Amaldi patch.

3 April 2012

Just two days after a flawless docking with the ISS on 29 March, ESA's third ATV has conducted its first 'test' reboost, proving that it is fully integrated with the Station and ready to perform orbit boosts and manoeuvres if necessary.

ATV Edoardo Amaldi approaches ISS

ESA's ATV Edoardo Amaldi completed a technically perfect automated docking with the Russian Zvezda module of the International Space Station (ISS) at 00:31 CEST on 29 March. The procedure was monitored by ESA astronaut André Kuipers and Russian cosmonaut Oleg Kononenko from inside the ISS and by the ESA/CNES mission operations team at the ATV Control Centre, Toulouse.

Docking marked the start of an intensive period of activity to open the hatch, enter ATV and confirm that all its systems were operating normally and were fully integrated with the data, electrical and other systems of the ISS. 

Kuipers and Kononenko during ATV-3 docking

Crew enters ATV for the first time

Hatch opening and first ingress took place at 16:15 CEST, and the crew installed an air scrubber to remove any contaminants that may have come loose inside ATV's pressurised cargo area.

 First image of Kuipers inside ATV-3

Early on 30 March, the crew also installed the Russian POTOK air filter unit as a measure against any bacterial contamination that may have occurred on ground before the hatch was closed for launch.

Electrical fault triggers circuit breaker

At 03:39 CEST, the ATV experienced a fault in one of the two channels of the onboard electronics system that controls its electrical power connections to the Zvezda module.

"The ATV system is designed to handle this kind of failure so it promptly shut down the faulty equipment and made sure everything was safe," said ESA's Charlotte Beskow, ATV Operation Interface Manager.

"It's a bit like when you blow a fuse at home, you do not know exactly what went wrong but your house is safe."

Later, ground teams sent commands that isolated ATV's electrical systems from the rest of the Station.

"As a precaution, the crew were asked to begin unloading priority cargo, in case the ISS power supply to ATV could not be re-established and — in the worst case of onboard autonomous power shortage — if we had to undock," says Massimo Cislaghi, ESA's ATV-3 Mission Manager.

"This would have been necessary in case of additional ATV onboard anomalies, while in the nominal case the amount of power ATV can generate from its own solar arrays would have still been sufficient for a long time even without ISS power."

After consultations between the crew, ATV Control Centre and the ISS Mission Control Centres in Houston and Moscow, the ATV power connection to the ISS was switched to a redundant channel. Power from the ISS to ATV was re-established at 19:03 CEST on 31 March.

Teams are investigating the problem to determine the cause of the electrical fault.

Kuipers unloading priority cargo from ATV-3

First Station boost using ATV thrusters

Once the power issue was resolved, mission controllers at ATV-CC began working on the first 'test' reboost of the ISS, conducted during the evening of 31 March.

ATV's thrusters ran for 351 seconds, increasing ISS velocity by 1.0 m/s and boosting average altitude by 1.73 km.

"In the boost test, ATV thrusters are commanded by the Russian computers inside the Zvezda module," says Charlotte Beskow.

"This is a standard test performed as soon as possible after docking."

The successful test burn means that ATV is ready for a series of larger planned reboosts (the first expected on 5 April) and to conduct debris avoidance manoeuvres when necessary.

Related links:

Automated Transfer Vehicle:

ATV blog:

Images, Text, Credits: ESA / NASA / Don Pettit.

Best regards,

Fermi Observations of Dwarf Galaxies Provide New Insights on Dark Matter

NASA - Fermi Gamma-ray Space Telescope logo.

March 3, 2012

There's more to the cosmos than meets the eye. About 80 percent of the matter in the universe is invisible to telescopes, yet its gravitational influence is manifest in the orbital speeds of stars around galaxies and in the motions of clusters of galaxies. Yet, despite decades of effort, no one knows what this "dark matter" really is. Many scientists think it's likely that the mystery will be solved with the discovery of new kinds of subatomic particles, types necessarily different from those composing atoms of the ordinary matter all around us. The search to detect and identify these particles is underway in experiments both around the globe and above it.

Scientists working with data from NASA's Fermi Gamma-ray Space Telescope have looked for signals from some of these hypothetical particles by zeroing in on 10 small, faint galaxies that orbit our own. Although no signals have been detected, a novel analysis technique applied to two years of data from the observatory's Large Area Telescope (LAT) has essentially eliminated these particle candidates for the first time.

Video above: No one knows what dark matter is, but it constitutes 80 percent of the matter in our universe. By studying numerous dwarf galaxies -- satellite systems that orbit our own Milky Way galaxy -- NASA's Fermi Gamma-ray Space Telescope has produced some of the strongest limits yet on the nature of the hypothetical particles suspected of making up dark matter. (Credit: NASA's Goddard Space Flight Center).

"In effect, the Fermi LAT analysis compresses the theoretical box where these particles can hide," said Jennifer Siegal-Gaskins, a physicist at the California Institute of Technology in Pasadena, Calif., and a member of the Fermi LAT Collaboration. Earlier today, she discussed the latest results of space-based dark matter searches in an invited talk at a meeting of the American Physical Society (APS) in Atlanta, Ga.

WIMPs, or Weakly Interacting Massive Particles, represent a favored class of dark matter candidates. Some WIMPs may mutually annihilate when pairs of them interact, a process expected to produce gamma rays -- the most energetic form of light -- that the LAT is designed to detect.

"One of the best places to look for these faint gamma-ray signals is in dwarf spheroidal galaxies, small satellites of our own Milky Way galaxy that we know possess large amounts of dark matter," Siegal-Gaskins explained. "From an astrophysical perspective, these are downright boring systems, with little gas or star formation and no objects like pulsars or supernova remnants that emit gamma rays."

In addition, many dwarfs lie far away from the plane of our galaxy, which produces a broad band of diffuse gamma-ray emission that stretches all around the sky. Selecting only dwarf galaxies at great distances from this plane helps minimize interference from the Milky Way.

Image above: This dwarf spheroidal galaxy in the constellation Fornax is a satellite of our Milky Way and is one of 10 used in Fermi's dark matter search. The motions of the galaxy's stars indicate that it is embedded in a massive halo of matter that cannot be seen. (Credit: ESO/Digital Sky Survey 2).

The team examined two years of LAT-detected gamma rays with energies in the range from 200 million to 100 billion electron volts (GeV) from 10 of the roughly two dozen dwarf galaxies known to orbit the Milky Way. Instead of analyzing the results for each galaxy separately, the scientists developed a statistical technique -- they call it a "joint likelihood analysis" -- that evaluates all of the galaxies at once without merging the data together. No gamma-ray signal consistent with the annihilations expected from four different types of commonly considered WIMP particles was found.

For the first time, the results show that WIMP candidates within a specific range of masses and interaction rates cannot be dark matter. A paper detailing these results appeared in the Dec. 9, 2011, issue of Physical Review Letters.

"The fact that we look at 10 dwarf galaxies jointly not only increases the statistics, but it also makes the analysis much less sensitive to fluctuations in the gamma-ray background and to uncertainties in the way the dark matter may be distributed around the dwarfs," said Maja Llena Garde, a graduate student at Stockholm University in Sweden and a co-author of the study.

For any given properties of a dark matter particle, the distribution of the particles has a significant impact on the expected gamma-ray signal, a wrinkle that often is handled inadequately, if at all, in previous studies.

The motions of a dwarf galaxy's stars trace out the profile of the massive dark matter halo in which they're embedded, but these tiny galaxies often have very few stars to track. The result is uncertainty in the way dark matter is distributed along the line of sight to the dwarf, which affects the expected flux of gamma rays detected by the LAT. By addressing uncertainties in the dwarfs' dark matter profiles, the LAT team's results are among the most accurate.

"An important element of this work is that we were able to take the statistical uncertainties from an updated study of the dwarf stellar motions and factor it into the LAT data analysis," said Johann Cohen-Tanugi, a physicist at the Laboratory of the Universe and Particles at the University of Montpellier 2 in France and a member of the research team.

"This treatment constitutes a significant step forward, and we hope that future studies will follow our example," noted co-author Jan Conrad, a physics professor at Stockholm University.

Video above: Fermi’s Large Area Telescope (LAT) is the spacecraft’s main scientific instrument. This animation shows a gamma ray (purple) entering the LAT, where it is converted into an electron (red) and a positron (blue). The paths of the particles point back to the gamma-ray source. The LAT maps the whole sky every three hours. (Credit: NASA's Goddard Space Flight Center).

The team is in the process of following up the two-year analysis with new ones that will incorporate additional Fermi observing time, improvements made to the LAT's sensitivity and the inclusion of higher-energy gamma rays. Additionally, sky surveys now ramping up may discover new dwarf galaxies that can be included in future studies.

Other members of the LAT Collaboration presenting APS talks on Fermi's dark matter work include Alex Drlica-Wagner and Elliott Bloom, both from the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), jointly located at SLAC National Accelerator Laboratory and Stanford University, Calif.

On Tuesday, April 3, William Atwood, a physicist at the Santa Cruz Institute for Particle Physics at the University of California Santa Cruz, will deliver his APS prize lecture on the development of Fermi. Atwood was the originator and principal architect of Fermi's LAT. He also played a role in shaping the alliance of physicists from the U.S., Europe, and Japan that forms the LAT Collaboration. For his leading work on the design, construction and use of Fermi's Large Area Telescope, the society awarded him its 2012 W. K. H. Panofsky Prize in Experimental Particle Physics.

Related Links:

Gamma Rays Carry No Trace of Dark Matter:

Physicist Bill Atwood Awarded Panofsky Prize in Experimental Particle Physics:

Image (mentioned), Videos (mentioned), Text, Credit: NASA's Goddard Space Flight Center / Francis Reddy.


lundi 2 avril 2012

ISS Test correction was successful

ISS - International Space Station patch.


April 1 in accordance with the program to ensure the ballistic flight of the International Space Station, a test was carried out of its orbit correction using the two main engines of the cargo ship ATV-3 "Edoardo Amaldi." Maintaining the desired spatial position of the ISS to the motor orientation of the Russian Service Module "Zvezda" and the cargo ship "Progress M-14M."


According to the ballistic Service Mission Control Center Engineering Research Institute engines were included in the 1 o'clock 54 minutes 04 seconds Moscow Time (March 31 at 21:54:04 GMT) and worked for 440 seconds.

As a result, ISS has added impetus to the 1 meter per second. The average height of its orbit has increased by 1.7 kilometers and reached 389.78 km.

Image, Text, Credits: Press-service of Federal Space Agency (Roscosmos PAO) and the PCO / NASA / Translation:

Original text in Russian: