vendredi 18 mars 2011

WISE's Last Light

NASA - WISE Mission logo.

March 18, 2011

On the morning of Feb. 1, 2011, WISE, or the Wide-field Infrared Survey Explorer, took its last snapshot of the sky. This 'last light' image is reminiscent of the 'first light' image from WISE, taken only 13 months prior. WISE's final picture shows thousands of stars in a patch of the Milky Way galaxy, covering an area three times the size of the full moon, in the constellation Perseus.

After its coolant ran out in October 2010, WISE warmed up from minus minus 436 to minus 328 degrees Fahrenheit (260 degrees to minus 200 degrees Celsius). This image contains data from the two detectors largely unaffected by the warmer temperatures. This region of the sky had been observed by WISE previously in all four of its detectors as part of its primary survey. There is no noticeable difference in the quality between that first image and this newer one, imaged at 3.4 and 4.6 microns.

In the short 13 months that WISE surveyed the sky, it produced millions of infrared images. It covered the whole sky at its four bands, and covered it twice at 3.4 and 4.6 microns. Now that the survey is complete, WISE is being put into hibernation. While the satellite sleeps and circles more than 500 kilometers (about 310 miles) above the Earth's surface, the WISE team is busily preparing its data for two big public releases: one this April, and the final release in the spring of 2012.

Image, Text, Credits: NASA / JPL-Caltech /UCLA.


NASA'S MESSENGER Spacecraft Begins Historic Orbit Around Mercury

NASA - MESSENGER Mission to Mercury patch.

March 18, 2011

NASA's MESSENGER spacecraft successfully achieved orbit around Mercury at approximately 9 p.m. EDT Thursday. This marks the first time a spacecraft has accomplished this engineering and scientific milestone at our solar system's innermost planet.

"This mission will continue to revolutionize our understanding of Mercury during the coming year," said NASA Administrator Charles Bolden, who was at MESSENGER mission control at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., as engineers received telemetry data confirming orbit insertion. "NASA science is rewriting text books. MESSENGER is a great example of how our scientists are innovating to push the envelope of human knowledge."

This animation follows MESSENGER’s journey from launch on August 3, 2004, through flybys of Earth, Venus, and Mercury, to arrival at Mercury for orbit insertion on March 18, 2011 (UTC).  The relative motions of Earth, Venus, Mercury, and the MESSENGER spacecraft, which completed nearly 16 orbits around the Sun, are shown in the plane of Earth’s orbit.  The timeline at the bottom tracks the spacecraft’s progress from launch to Mercury orbit insertion.
At 9:10 p.m. EDT, engineers Operations Center, received the anticipated radiometric signals confirming nominal burn shutdown and successful insertion of the MESSENGER probe into orbit around the planet Mercury. NASA's MErcury Surface, Space ENvironment, Geochemistry, and Ranging, or MESSENGER, rotated back to the Earth by 9:45 p.m. EDT, and started transmitting data. Upon review of the data, the engineering and operations teams confirmed the burn executed nominally with all subsystems reporting a clean burn and no logged errors.

MESSENGER's main thruster fired for approximately 15 minutes at 8:45 p.m., slowing the spacecraft by 1,929 miles per hour and easing it into the planned orbit about Mercury. The rendezvous took place about 96 million miles from Earth.

"Achieving Mercury orbit was by far the biggest milestone since MESSENGER was launched more than six and a half years ago," said Peter Bedini, MESSENGER project manager of the Applied Physics Laboratory (APL). "This accomplishment is the fruit of a tremendous amount of labor on the part of the navigation, guidance-and-control, and mission operations teams, who shepherded the spacecraft through its 4.9-billion-mile journey."

This animation depicts some of the science operations that will be completed during a typical single
orbit in the first week of scientific mapping. At different parts of the orbit, different instruments control spacecraft pointing. Blue frames on the planet denote imaging with either MESSENGER's wide-angle or narrow-angle camera. The green line denotes an observation of Mercury's exosphere with MESSENGER's Ultraviolet and Visible Spectrometer. The red circles denote topographic profiling with the Mercury Laser Altimeter. The magenta scans denote remote sensing of surface elemental composition by MESSENGER's X-Ray Spectrometer and Gamma-Ray and Neutron Spectrometer. Time during the animation is unevenly scaled to time in orbit to permit several of the principal scientific operations to be displayed clearly.

For the next several weeks, APL engineers will be focused on ensuring the spacecraft's systems are all working well in Mercury's harsh thermal environment. Starting on March 23, the instruments will be turned on and checked out, and on April 4 the mission's primary science phase will begin.

"Despite its proximity to Earth, the planet Mercury has for decades been comparatively unexplored," said Sean Solomon, MESSENGER principal investigator of the Carnegie Institution of Washington. "For the first time in history, a scientific observatory is in orbit about our solar system's innermost planet. Mercury's secrets, and the implications they hold for the formation and evolution of Earth-like planets, are about to be revealed."

APL designed and built the spacecraft. The lab manages and operates the mission for NASA's Science Mission Directorate in Washington.

For more information about the mission, visit:

Images, Videos, Text, Credits: NASA / APL.


jeudi 17 mars 2011

ISS Orbit to be Readjusted before Next Arrival

ISS - International Space Station patch / ESA - ATV2 Johannes Kepler Mission patch.


The orbit of the International Space Station (ISS) will be raised by 3.7 kilometers (2.3 miles) on Friday, Russian Mission Control said on Thursday.

Artist impression of the ATV being used to raise the altitude of the ISS

The readjustment is necessary to ensure the best conditions to dock Russia's Soyuz TMA-21 piloted spacecraft and the U.S. Endeavor space shuttle.

"The maneuver will be conducted using the two main engines on board the European Space Agency's Automated Transfer Vehicle (ATV-2), named after Johannes Kepler," the Mission Control said in a statement.

ESA animation, ATV was used to raise the orbit of the International Space Station

The ATV-2 docked with the ISS on February 24. It will stay in orbit for three months, and will be used mainly to adjust the station's orbit.

Corrections to the space station's orbit are conducted periodically before launches of Russian spacecraft and U.S. shuttles to compensate for the Earth's gravity and to safeguard successful dockings.

Russia's Soyuz TMA-21 is expected to travel to the ISS sometime in early April, while the U.S. Endeavor will blast off from Cape Canaveral on April 19.

Images, Video, Text, Credits: Roscosmos PAO / ESA / D.Ducros.

Best regards,

ESA - An unexpected travelling companion

ESA - MagISStra Mission patch.

17 March 2011

Gardens are always a source of surprises. After three weeks of steady growth in space under the watchful eye of the ESA astronaut Paolo Nespoli, the baby space plants of the Greenhouse in Space project have found a new – and unexpected - travelling companion.

The International Space Station (ISS) ecosystem is particularly a delicate one. Whereas some residuals don’t harm much the earthly plants or humans, the balance of the closed systems present in the Station should not be compromised.

An unexpected green travelling companion growing in the Greenhouse in Space

It is known that spaceflight reduces the ability of the crew's immune systems to fight off possible infections and once safety experts confirmed the presence of unexpected particles in the greenhouse, an unavoidable decision was made to carefully remove the greenhouse from the ISS, thus avoiding any probability of causing any harm to the astronauts. 

The Arabidopsis plants, already having proved themselves as a hardy growers in space, seemed to grow very well despite the uninvited hitch-hiker on board.

Paolo was the first one to remark that simple procedures on Earth are extremely complex and possibly dangerous in weightlessness. "Part of the experiment was indeed a success: we were able to grow the plants and observe them."

Paolo with greenhouse at the Space Station

Even though some experiments can go wrong, Paolo said, "This is a lesson to be learned that we can leave to the future astronauts. I’m sure they will get even better at it."

From real Space Station to virtual Mars spacecraft

The Greenhouse in Space education project moves on and encourages participating students throughout Europe to continue their experiments and monitor their plants even more closely. Now it is time to compare their greenhouses with the martian ones, as the crew of Mars500 found four of these little greenhouses packed in their lander module with all other cargo.

Now they are carefully growing the same plants in their spacecraft-like modules and the results are coming in – have a look at the video below.

Romain with greenhouses inside the Mars500 facility

The Greenhouse in Space education project started on 17 February and is being carried out by more than 800 school children throughout Europe. The first online lesson is now posted on ESA educational web pages, where the results of all the participants can be checked and compared.

After three weeks

The Project's group on Facebook has discussions and photos. Teachers can follow the lesson online and should send their class results to the HSF education team at the end of the project.

Related Links:

The first online lesson:

The Project's group on Facebook:

Human Spaceflight Education:

Images, Text, Credits: ESA.


mercredi 16 mars 2011

NASA Lunar Reconnaissance Orbiter Delivers Treasure Trove Of Data

NASA - Lunar Reconnaissance Orbiter (LRO) patch.

March 16, 2011

NASA's Lunar Reconnaissance Orbiter (LRO) team released Tuesday the final set of data from the mission's exploration phase along with the first measurements from its new life as a science satellite.

 LRO in Moon orbit

With this fifth release of data, striking new images and maps have been added to the already comprehensive collection of raw lunar data and high-level products, including mosaic images, that LRO has made possible. The spacecraft's seven instruments delivered more than 192 terabytes of data with an unprecedented level of detail. It would take approximately 41,000 typical DVDs to hold the new LRO data set.
"The release of such a comprehensive and rich collection of data, maps and images reinforces the tremendous success we have had with LRO in the Exploration Systems Mission Directorate and with lunar science," said Michael Wargo, chief lunar scientist of the Exploration Systems Mission Directorate at NASA Headquarters in Washington.

Among the latest products is a global map with a resolution of 100 meters per pixel from the Lunar Reconnaissance Orbiter Camera (LROC). To enhance the topography of the moon, this map was made from images collected when the sun angle was low on the horizon. Armchair astronauts can zoom in to full resolution with any of the mosaics—quite a feat considering that each is 34,748 pixels by 34,748 pixels, or approximately 1.1 gigabytes.

Video above: With LRO's wide angle camera, scientists can create a global catalog of the mountains, craters, and rilles on the moon. Credit: NASA / Goddard Space Flight Center.

"Because the moon is so close and because we have a dedicated ground station, we are able to bring back as much data from LRO as from all the other planetary missions combined," said LRO Project Scientist Richard Vondrak of NASA's Goddard Space Flight Center in Greenbelt, Md.

LRO's Diviner Lunar Radiometer Experiment is providing new data relating to the moon's surface. These include maps of visual and infrared brightness, temperature, rock abundance, nighttime soil temperature and surface mineralogy. The data are in the form of more than 1700 digital maps at a range of resolutions that can be overlaid easily on other lunar data sets.

Image above: LOLA data give us three complementary views of the near side of the moon: the topography (left) along with new maps of the surface slope values (middle) and the roughness of the topography (right). All three views are centered on the relatively young impact crater Tycho, with the Orientale basin on the left side.

The slope magnitude indicates the steepness of terrain, while roughness indicates the presence of large blocks, both of which are important for surface operations. Lunar topography is the primary measurement being provided, while ancillary datasets are steadily being filled in at the kilometer scale. Credit: NASA / LRO / LOLA Science Team.

The Lyman-Alpha Mapping Project, which collects information to help identify surface water-ice deposits, especially in permanently-shadowed regions of the moon, also has new data. This release includes new maps of far-ultraviolet (FUV) brightness, albedo and water-ice data as well as instrument exposure, illumination and other conditions.

As a complement to the high-resolution digital elevation maps, representing 3.4 billion measurements already released by the Lunar Orbiter Laser Altimeter team, the group is delivering new maps of slope, roughness and illumination conditions. New maps from the Lunar Exploration Neutron Detector, and the latest data from the Cosmic Ray Telescope for the Effects of Radiation and the Miniature Radio Frequency instruments, also are featured.

Image above: The lunar farside as never seen before! LROC WAC orthographic projection centered at 180° longitude, 0° latitude Credit: NASA / Goddard / Arizona State University.

"All these global maps and other data are available at a very high resolution -- that's what makes this release exciting," said Goddard's John Keller, the LRO deputy project scientist. "With this valuable collection, researchers worldwide are getting the best view of the moon they have ever had."

The complete data set contains the raw information and high-level products such as mosaic images and maps. The data set also includes more than 300,000 calibrated data records released by LROC. All of the final records from the exploration phase, which lasted from Sept. 15, 2009 through Sept. 15, 2010, are available through several of the Planetary Data System nodes and the LROC website.
To access LRO data, visit:

LRO was built and is managed by Goddard. The exploration phase was funded by NASA's Exploration Systems Missions Directorate. LRO operates under NASA's Science Mission Directorate. For more information about LRO, visit:

Images (mentioned), Video, Text, Credits: NASA / NASA Planetary Science / Goddard Space Flight Center.


Expedition 26 Crew And Capsule Land Safely In Kazakhstan

ROSCOSMOS - Soyuz TMA-01M Mission patch.

March 16, 2011

Expedition 26 Commander Scott Kelly and Russian Flight Engineers Alexander Kaleri and Oleg Skripochka safely landed their Soyuz spacecraft on the Kazakhstan steppe Wednesday, wrapping up a five-month stay aboard the International Space Station.

The new Soyuz TMA-01M is seen closing on the ISS

Kaleri, the Soyuz commander, was at the controls of the spacecraft as it undocked at 12:27 a.m. EDT from the station's Poisk module. The trio landed at 3:54 a.m. (1:54 p.m. local time) at a site northeast of the town of Arkalyk.

Working in frigid temperatures, Russian recovery teams were on hand to help the crew exit the Soyuz and adjust to gravity. Kaleri and Skripochka will return to the Gagarin Cosmonaut Training Center in Star City, outside of Moscow, while Kelly will fly directly home to Houston.

Soyuz TMA-01M Crews

The trio launched aboard the Soyuz TMA-01M spacecraft from the Baikonur Cosmodrome in Kazakhstan on Oct. 8, 2010. As members of the Expedition 25 and 26 crews, they spent 159 days in space, 157 of them aboard the station.

During their mission, the Expedition 25 and 26 crew members worked on more than 150 microgravity experiments in human research; biology and biotechnology; physical and materials sciences; technology development; and Earth and space sciences.

A quick succession of international space vehicles arrived on the station's loading docks during Expedition 26. The Japanese Kounotori2, or "white stork," H-II Transfer Vehicle 2; the Russian cargo ship Progress 41; the European Jules Verne Automated Transfer Vehicle; and space shuttle Discovery delivered more than 11 tons of supplies necessary for working and living aboard the station.

Soyuz TMA-01M Highlights Undocking, Landing

Kelly has logged more than 180 days in space, and Kaleri has more than 770. Skripochka has completed his first space mission. Expedition 27 Commander and Russian Cosmonaut Dmitry Kondratyev and Flight Engineers Cady Coleman of NASA and Paolo Nespoli of the European Space Agency remain aboard the station.

A new trio of Expedition 27 flight engineers, NASA astronaut Ron Garan and Russian cosmonauts Andrey Borisenko and Alexander Samokutyaev, will launch from the Baikonur Cosmodrome no earlier than March 29.

For more information about the space station, visit:

For a schedule of upcoming flights to the station, visit:

To view Coleman's and Garan's mission updates on their Twitter pages, visit: and

Images, Text, Video, Credits: ROSCOSMOS / NASA / NASA TV.


ESO - The Drama of Starbirth

ESO - European Southern Observatory logo.

16 March 2011

New-born stars wreak havoc in their nursery

Close-up of the drama of star formation

A new image from ESO’s Very Large Telescope gives a close-up view of the dramatic effects new-born stars have on the gas and dust from which they formed. Although the stars themselves are not visible, material they have ejected is colliding with the surrounding gas and dust clouds and creating a surreal landscape of glowing arcs, blobs and streaks.

The star-forming region NGC 6729 is part of one of the closest stellar nurseries to the Earth and hence one of the best studied. This new image from ESO’s Very Large Telescope gives a close-up view of a section of this strange and fascinating region (a wide-field view is available here: eso1027). The data were selected from the ESO archive by Sergey Stepanenko as part of the Hidden Treasures competition [1]. Sergey’s picture of NGC 6729 was ranked third in the competition.

Star formation in the constellation of Corona Australis

Stars form deep within molecular clouds and the earliest stages of their development cannot be seen in visible-light telescopes because of obscuration by dust. In this image there are very young stars at the upper left of the picture. Although they cannot be seen directly, the havoc that they have wreaked on their surroundings dominates the picture. High-speed jets of material that travel away from the baby stars at velocities as high as one million kilometres per hour are slamming into the surrounding gas and creating shock waves. These shocks cause the gas to shine and create the strangely coloured glowing arcs and blobs known as Herbig–Haro objects [2].

ESO - Zooming in on a stellar nursery in Corona Australis

In this view the Herbig–Haro objects form two lines marking out the probable directions of ejected material. One stretches from the upper left to the lower centre, ending in the bright, circular group of glowing blobs and arcs at the lower centre. The other starts near the left upper edge of the picture and extends towards the centre right. The peculiar scimitar-shaped bright feature at the upper left is probably mostly due to starlight being reflected from dust and is not a Herbig–Haro object.

Close-up of the drama of star formation (annotated)

This enhanced-colour picture [3] was created from images taken using the FORS1 instrument on ESO’s Very Large Telescope. Images were taken through two different filters that isolate the light coming from glowing hydrogen (shown as orange) and glowing ionised sulphur (shown as blue). The different colours in different parts of this violent star formation region reflect different conditions — for example where ionised sulphur is glowing brightly (blue features) the velocities of the colliding material are relatively low — and help astronomers to unravel what is going on in this dramatic scene.


[1] ESO’s Hidden Treasures 2010 competition gave amateur astronomers the opportunity to search through ESO’s vast archives of astronomical data, hoping to find a well-hidden gem that needed polishing by the entrants. Participants submitted nearly 100 entries and ten skilled people were awarded some extremely attractive prizes, including an all expenses paid trip for the overall winner to ESO’s Very Large Telescope (VLT) on Cerro Paranal, in Chile, the world’s most advanced optical telescope. The ten winners submitted a total of 20 images that were ranked as the highest entries in the competition out of the near 100 images.

[2] The astronomers George Herbig and Guillermo Haro were not the first to see one of the objects that now bear their names, but they were the first to study the spectra of these strange objects in detail. They realised that they were not just clumps of gas and dust that reflected light, or glowed under the influence of the ultraviolet light from young stars, but were a new class of objects associated with ejected material in star formation regions.

[3] Both the ionised sulphur and hydrogen atoms in this nebula emit red light. To differentiate between them in this image the sulphur emission has been coloured blue.

More information:

ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive astronomical observatory. 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 VISTA, the world’s largest survey telescope. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 42-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.


    * Science paper (Wang et al.):

    * Photos of the VLT:

Images, Video, Text, Credits: ESO / IAU and Sky & Telescope / Video: ESO/S. Brunier / Loke Kun Tan ( Music: John Dyson (from the album "Darklight").


mardi 15 mars 2011

Japan Quake May Have Shortened Earth Days, Moved Axis - Status of Dammaged Nuclear Plants

NASA - ASTER- EOS TERRA Satellite patch / ISS - International Space Station patch.


The March 11, magnitude 9.0 earthquake in Japan may have shortened the length of each Earth day and shifted its axis. But don't worry—you won't notice the difference.

Using a United States Geological Survey estimate for how the fault responsible for the earthquake slipped, research scientist Richard Gross of NASA's Jet Propulsion Laboratory, Pasadena, Calif., applied a complex model to perform a preliminary theoretical calculation of how the Japan earthquake—the fifth largest since 1900—affected Earth's rotation. His calculations indicate that by changing the distribution of Earth's mass, the Japanese earthquake should have caused Earth to rotate a bit faster, shortening the length of the day by about 1.8 microseconds (a microsecond is one millionth of a second).

Image above: The March 11, 2011, great earthquake in Japan may have shortened the length of Earth days and shifted its axis. Image credit: NASA.

The calculations also show the Japan quake should have shifted the position of Earth's figure axis (the axis about which Earth's mass is balanced) by about 17 centimeters (6.5 inches), towards 133 degrees east longitude. Earth's figure axis should not be confused with its north-south axis; they are offset by about 10 meters (about 33 feet). This shift in Earth's figure axis will cause Earth to wobble a bit differently as it rotates, but it will not cause a shift of Earth's axis in space—only external forces such as the gravitational attraction of the sun, moon and planets can do that.

Both calculations will likely change as data on the quake are further refined.

In comparison, following last year's magnitude 8.8 earthquake in Chile, Gross estimated the Chile quake should have shortened the length of day by about 1.26 microseconds and shifted Earth's figure axis by about 8 centimeters (3 inches). A similar calculation performed after the 2004 magnitude 9.1 Sumatran earthquake revealed it should have shortened the length of day by 6.8 microseconds and shifted Earth's figure axis by about 7 centimeters, or 2.76 inches. How an individual earthquake affects Earth's rotation depends on its size (magnitude), location and the details of how the fault slipped.

Gross said that, in theory, anything that redistributes Earth's mass will change Earth's rotation.

"Earth's rotation changes all the time as a result of not only earthquakes, but also the much larger effects of changes in atmospheric winds and oceanic currents," he said. "Over the course of a year, the length of the day increases and decreases by about a millisecond, or about 550 times larger than the change caused by the Japanese earthquake. The position of Earth's figure axis also changes all the time, by about 1 meter (3.3 feet) over the course of a year, or about six times more than the change that should have been caused by the Japan quake."

Gross said that while we can measure the effects of the atmosphere and ocean on Earth's rotation, the effects of earthquakes, at least up until now, have been too small to measure. The computed change in the length of day caused by earthquakes is much smaller than the accuracy with which scientists can currently measure changes in the length of the day. However, since the position of the figure axis can be measured to an accuracy of about 5 centimeters (2 inches), the estimated 17-centimeter shift in the figure axis from the Japan quake may actually be large enough to observe if scientists can adequately remove the larger effects of the atmosphere and ocean from the Earth rotation measurements. He and other scientists will be investigating this as more data become available.

Gross said the changes in Earth's rotation and figure axis caused by earthquakes should not have any impacts on our daily lives. "These changes in Earth's rotation are perfectly natural and happen all the time," he said. "People shouldn't worry about them."

Images, Text, Credits: NASA / Alan Buis / JPL.

NASA Satellite Sees Area Affected by Japan Tsunami

A new before-and-after image pair from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft shows a region of Japan's northeastern coast, northeast of the city of Sendai, which was affected by the March 11, 2011 tsunami.

Image above: A new before-and-after image pair from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft shows a region of Japan's northeastern coast, northeast of the city of Sendai, affected by the March 11, 2011, tsunami. The image at the left is from March 14, 2011; the right-hand image is from August 2008. Image credit: NASA /GSFC / METI / ERSDAC / JAROS.

The images show the coastal cities of Ofunato and Kesennuma, located about 90 kilometers (55 miles) northeast of Sendai. Ofunato has a population of about 42,000, while the population of Kesennuma is about 73,000. Areas covered by vegetation are shown in red, while cities and unvegetated areas are shown in shades of blue-gray. The image on the left was acquired on March 14, 2011; the image on the right was acquired in August 2008. When compared closely, vegetation is no longer visible in many coastal areas in the new image, particularly around Kesennuma. Scientists believe this is most likely due to the effects of the tsunami.

The images show an area located at 39.4 degrees north latitude, 141.9 degrees east longitude, and cover an area of 28 by 46 kilometers (17 by 27 miles).

For more information, see: and

Images, Text, Credits: NASA / Alan Buis / JPL.

Tsunami Damage near Ishinomaki, Japan

The Japanese city of Ishinomaki was one of the hardest hit when a powerful tsunami swept ashore on March 11, 2011. When the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite acquired the bottom image three days later, on March 14, water still inundated the city. The top image, from August 8, 2008, shows water levels under normal circumstances.

Water is dark blue in this false-color image. Plant-covered land is red, exposed earth is tan, and the city is silver. Standing water is most evident in the flat, open places that were once fields. The most extensive flooding is around the Matsushima Air Base in the lower left corner of the image. According to news reports, several airplanes were damaged in the tsunami. The neighborhoods immediately around the airstrip are also flooded.

Dark blue fills in the spaces between buildings in sections of Ishinomaki near the harbor in the center of the image and by the river in the upper right. These areas are probably flooded. Survivors in parts of Ishinomaki were being rescued in boats, reported CNN. The large image shows additional flooding near Ishinomaki and farther south in Sendai.

Image, Text,  Credit: NASA Earth Observatory image created by Jesse Allen, using data provided courtesy of NASA / GSFC / METI / ERSDAC / JAROS, and U.S ./ Japan ASTER Science Team.

Sendai Coast From Space Station

From 220 miles above Japan, an Expedition 26 crew member onboard the International Space Station took this 200mm view of the Sendai coast and southward, on March 14, three days after the one-two-punch of earthquake and tsunami.

Station Crew Photographs Sendai

From 220 miles above Japan, an Expedition 26 crew member onboard the International Space Station took this 800mm view of Sendai, and the coast mostly north on March 13. Sunglint helps to highlight the flood waters over the land, flowing out the rivers, plus the heavy oils swirling on the surface with the currents. An earthquake and subsequent tsunami hit Japan on March 11.

Images, Text, Credit: NASA.

New Fire Hits Japanese Nuclear Plant

A new fire broke out Wednesday in an already fire-damaged reactor at a crippled nuclear power plant in Fukushima, Japan.

Tokyo Electric Power Co. spokesman Hajimi Motujuku says the blaze erupted early Wednesday in the outer housing of the reactor's containment vessel. It wasn't clear if the second fire at the plant's reactor No. 4 in as many days is a new blaze, or if the first fire wasn't fully extinguished. Firefighters are trying to put out the flames. Japan's nuclear safety agency also confirmed the fire, whose cause was not immediately known.

Inside The Nuclear Reactors - Latest Problems

Tuesday's fire and an apparent explosion damaged the reactor's roof, and there are concerns that the spent fuel rods are overheating. About three hours after the blaze erupted Wednesday, Japan's nuclear safety agency said fire and smoke could no longer be seen at Unit 4, but that it was unable to confirm that the blaze had been put out.

Also Wednesday, the agency said 70 percent of the nuclear fuel rods may have been damaged at another Fukushima Daiichi reactor that was first stricken last week, triggering the crisis. "But we don't know the nature of the damage, and it could be either melting, or there might be some holes in them," said an agency spokesman, Minoru Ohgoda.

Inside The Nuclear Reactors - Normal Functioning

Desperate plant operators considered dramatic plans to stave off a meltdown in the reactor, including dumping water on it by helicopter. But plant operators worried that the water wouldn't reach the fuel rods. According to NHK television, officials at Tokyo Electric Power Co. decided a hole in the roof of the reactor was "dozens of meters" from the swimming-pool-like chamber where the spent fuel rods are overheating. So a helicopter dump, similar to putting out a forest fire, probably wouldn't reach the pool.

Moreover, officials say helicopters can't carry enough water to do the job. And Japanese Defense Ministry officials are worried about the safety of military personnel on the helicopters, according to Kyodo News. TEPCO, which operates the Fukushima power plant, is still considering the use of high-pressure fire hoses to spray cooling water into the spent fuel pool.

Inside The Nuclear Reactors - After The Quake

Radiation levels are far too high to permit workers to bring hoses anywhere near the pool's edge to re-flood it manually. U.S. nuclear safety experts agreed. David Lochbaum, director of the nuclear safety program at the Union of Concerned Scientists, says a study done for Connecticut nuclear power plants concluded that in a situation such as this one, radiation would be so intense that a worker at the pool's edge "would receive a lethal dose in something like 16 seconds."

The spent-fuel problem is a new wild card in the potentially catastrophic failure of the Fukushima power plant. Since last Friday's 9.0 earthquake, the plant has been wracked by repeated explosions in three different reactors. Some experts are now concerned that spent fuel rods may overheat in two other reactors, even though they were not in service at the time of the earthquake. Those two units, Nos. 5 and 6, have not yet reported problems.

Inside The Nuclear Reactors - Fixing The Problem

"There are accounts that they're having difficulties cooling those three spent fuel pools, and they need to regain control of that," says Lochbaum, a nuclear engineer by training. "Or as a minimum, need to be able to replace the water that may be evaporating or boiling away to prevent the water from dropping below the level of irradiated fuel in the bottom of those spent fuel pools to prevent their damage from overheating as well."

Radiation Concerns From Spent Fuel Rods

The problem at reactor No. 4 was apparently brewing for some time before Tuesday's fire. The company says the temperature of the spent fuel pool reached 183 degrees Fahrenheit on Monday — twice the normal level. It apparently went higher, but a "technical failure" prevented later readings. One concern is that the spent fuel pool may not have the radiation containment barriers that protect the reactor's fission vessel. Thus, melting fuel rods could become a significant source of radiation leakage into the environment.

Radiation levels spiked as high as 400 milliSieverts per hour at the plant's main gate during Tuesday's fire and explosion — a potentially dangerous and even fatal level if it's sustained. But the International Atomic Energy Agency (IAEA) reports the levels later dropped to much lower readings. Still, company officials evacuated all but 50 of the facility's 800 workers for their own safety. The IAEA says it's seeking "details about the status of all workers, reactors and spent fuel at the Fukushima Daiichi plant."

It is not clear how much radiation exposures increased in the 12-mile evacuation zone around the plant or beyond. Radiation levels went up transiently in Tokyo, but not to levels that pose any public health concern, officials say.

Image above: A nuclear plant specialist with the Tokyo Electric Power Co. explains the structure of a nuclear reactor at the company's Fukushima power plant during a news conference Tuesday.

The problems with spent fuel rods mean there are now two potential sources of radioactive leakage at the damaged plant. A second explosion on Tuesday in the plant's No. 2 reactor probably has caused a breach in the part of the heavy containment vessel known as the suppression chamber, or torus. That potentially allows radioactive steam or water to escape from a new route.

Previously, radioactivity emanated from controlled releases of steam in an attempt to depressurize the reactors and allow cooling seawater to be pumped in.

Images, Text, Credits: The Associated Press / AFP / Getty / Adam Cole, Andrew Prince, Maria Godoy, Stephanie d'Otreppe, Nelson Hsu / NPR / U.S. Nuclear Regulatory Commission.

Best regards,

Wheels Up For NASA Mission's Most Extensive Arctic Ice Survey

NASA - Operation Ice Bridge 2010 patch.

March 15, 2011

Researchers and flight crew arrived in Thule, Greenland, on Monday, March 14, for the start of NASA's 2011 Operation IceBridge, an airborne mission to study changes in Arctic polar ice. This year's plans include surveys of Canadian ice caps and expanded international collaboration.

The state of Earth's polar ice sheets, glaciers and sea ice is an important indicator of climate change and plays a key role in regulating global climate. With IceBridge, NASA is pushing ahead with its commitment to keep an eye on changes to polar ice to better understand the effects of climate change.

Since 2009, Operation IceBridge has flown annual campaigns over the Arctic starting in March and over Antarctica starting in October. The mission extends the multi-year record of ice elevation measurements made by NASA's Ice Cloud and land Elevation Satellite (ICESat), which stopped collecting data in 2009, and the upcoming ICESat-2, scheduled for launch in 2016.

"Each successive IceBridge campaign has broadened in scope," said IceBridge project scientist Michael Studinger of Goddard Earth Sciences and Technology Center at the University of Maryland. "This year, we have more flight hours and flight plans than ever before. We are looking forward to a busy, fruitful campaign."

The first science flight is scheduled for this week, pending favorable weather. For almost 10 weeks, researchers will operate an array of airborne instruments collecting data over Arctic land and sea ice.

Among the highest priority flights is an overnight transit to Fairbanks, Alaska, to collect sea ice thickness data across a slice of the Arctic Ocean. Sea ice is thought to be thinning in recent years in addition to shrinking in the area covered. Another high-priority flight plan is to fly over the Barnes and Devon ice caps of the Canadian Arctic Archipelago.

"The Canadian ice caps are notably smaller than the Greenland and Antarctic ice sheets, but are still significant potential contributors to sea-level change in the next few decades," said Charles Webb, deputy cryosphere program manager at NASA's Goddard Space Flight Center in Greenbelt, Md. "They also serve as potential early-warning indicators, responding more sensitively to temperature changes than the more massive ice sheets."


The IceBridge campaign also plans to fly for the first time over the European Space Agency's ground-based calibration sites for their ice-observing satellite, CryoSat-2. Flights over calibration sites ultimately are expected to provide data to evaluate and improve remote-sensing measurements.

Still other IceBridge missions will retrace paths flown in previous years, such as flights over Petermann, Jacobshavn, Kangerlussuak and Helheim glaciers. With this multi-year data, scientists can begin to see how such glaciers -- the outlets through which Greenland loses mass from its ice sheet -- are changing, where ice loss is slowing or accelerating, and why.

The P-3B aircraft from NASA's Wallops Flight Facility in Wallops Island, Va., will fly from Thule and Kagerlussuaq, Greenland, carrying a suite of instruments. The Airborne Topographic Mapper measures changes in the surface elevation of the ice by reflecting lasers from the ground back to the aircraft and converting the readings into elevation maps.

P-3B Ready For Start of Arctic 2011 Campaign

Radar instruments onboard the P-3B from the University of Kansas' Center for Remote Sensing of Ice Sheets in Lawrence, Kan., allow scientists to see snow and ice characteristics at the surface and down to the bedrock. A gravity instrument from Columbia University's Lamont-Doherty Earth Observatory in Palisades, N.Y., is used to peer below floating ice to determine the shape of water-filled cavities below.

NASA P3B Orion

Another laser altimeter, the Land, Vegetation, and Ice Sensor, operates at higher altitudes to survey large areas. This altimeter will fly solo out of Kangerlussuaq on the King Air B-200, an aircraft based at NASA's Langley Research Center in Hampton, Va.

The IceBridge campaign is led by Goddard. The Earth Science Project Office at NASA's Ames Research Center in Moffett Field, Calif., is responsible for integration of science experiments on the aircraft and mission logistics.

For more information about Operation IceBridge, visit:

Images, Video, Text, Credit: NASA / Goddard.


Paolo Nespoli’s MagISStra mission at midway point

ESA - MagISStra Mission patch.

15 March 2011

ESA astronaut Paolo Nespoli is now half way into his six-month mission on the International Space Station. Monday’s handover of command heralds the departure of three crewmembers and the arrival of a new trio in the coming weeks.

Expedition 26 Commander Scott Kelly handed over command of the Station to cosmonaut Dmitry Kondratyev during a ceremony yesterday evening.

ESA astronaut Paolo Nespoli (top) and Russian cosmonaut Alexander Kaleri, both Expedition 26 flight engineers

Kelly, Soyuz commander Alexander Kaleri and Russian flight engineer Oleg Skripochka will close the hatch and depart in their Soyuz TMA-01M spacecraft at 06:00 CET on Wednesday, 16 March.

The three Expedition 26 astronauts aim to land in northern Kazakhstan near the town of Arkalyk at 08:48 CET later that day.

The Expedition 27 crew of Paolo, new commander Dmitry Kondratyev and astronaut Cady Coleman will welcome fresh crewmembers in early April: Russian cosmonauts Alexander Samokutyaev and Andrey Borisenko, and NASA flight engineer Ron Garan.

Expedition 28

Russia’s Roscosmos space agency announced today that the launch of the new trio has been delayed from 30 March owing to technical checks required on their Soyuz TMA-21 spacecraft.

They will remain aboard the Station for about six months as Expedition 28.

Busy beginning for 2011

The last two months have been historic for the Space Station. The Space Shuttles are making their last visits and there have never been so many craft docked with the orbital complex.

Discovery as seen from ISS

Japan’s HTV-2 freighter began the sequence in January, before Russia’s Progress M-09M docked on 20 January. ESA’s ATV-2 roared into space atop an Ariane 5 on 16 February, docking majestically eight days later.

The latest visitor was Shuttle Discovery, leaving behind the European-built Leonardo module as a multipurpose storeroom.

The next Shuttle, targeted for launch on 19 April, will deliver the massive Alpha Magnetic Spectrometer. Also aboard is another Italian astronaut, ESA’s Roberto Vittori.

Paolo’s three months in space

Paolo Nespoli has now been in space for 89 days – midway through his MagISStra mission.

His duties include ISS flight engineer, conducting more than 30 scientific experiments and technology demonstrations, performing educational activities, participating in public relations events – and using much of his free time photographing Earth and tweeting.

Paolo Nespoli works with LMM

His Twitter account will soon reach 30 000 followers. His photostream is at

Paolo’s Expedition 27 will return to Earth at the end of May and Expedition 29 (Sergei Volkov, Mike Fossum and Satoshi Furukawa) will complete the crew in early June.

After Paolo and Roberto, the next European on the Station will be ESA’s Dutch astronaut André Kuipers in December.

Related link:

ISS Expedition 26 (NASA):

See the ISS:

Images, Text, Credits: ESA / NASA.

Best regards,

Arachnophobes Beware: Hubble Snaps Close-up of the Tarantula

ESA - Hubble Space Telescope logo.

15 March 2011

Hubble snaps close-up of the Tarantula

The NASA/ESA Hubble Space Telescope has produced an outstanding image of part of the famous Tarantula Nebula, a vast star-forming cloud of gas and dust in our neighbouring galaxy, the Large Magellanic Cloud. In this picture, we see a close-up of the Tarantula’s central region, glowing brightly with ionised gases and young stars.

Hubblecast 44 - Hubble spies on the Tarantula Nebula

The wispy arms of the Tarantula Nebula were originally thought to resemble spindly spider legs, giving the nebula its unusual name. The part of the nebula visible in this image from Hubble’s Advanced Camera for Surveys is criss-crossed with tendrils of dust and gas churned up by recent supernovae. These supernova remnants include NGC 2060, visible above and to the left of the centre of this image, which contains the brightest known pulsar.

Wide-field and close-up views of the Tarantula Nebula

The tarantula’s bite goes beyond NGC 2060. Near the edge of the nebula, outside the frame, below and to the right, lie the remains of supernova SN 1987a, the closest supernova to Earth to be observed since the invention of telescopes in the 17th century. Hubble and other telescopes have been returning to spy on this stellar explosion regularly since it blew up in 1987, and each subsequent visit shows an expanding shockwave lighting up the gas around the star, creating a pearl necklace of glowing pockets of gas around the remains of the star. SN 1987a is visible in wide field images of the nebula, such as that taken by the MPG/ESO 2.2-metre telescope.

Annotated wide-field view of the Tarantula Nebula

Together with dying stars, the Tarantula Nebula is packed with young stars which have recently formed from the nebula’s supply of hydrogen gas. These toddler-stars shine forth with intense ultraviolet light that ionises the gas, making it light up red. The light is so intense that although around 170 000 light-years distant, and outside the Milky Way, the Tarantula Nebula is nevertheless visible without a telescope on a dark night to Earth-bound observers. This nebula might be far away, but it is the most luminous example of its type that astronomers have observed in the local Universe.

ESO - Zooming into the Tarantula Nebula
A compact and extremely bright star cluster called RMC 136  lies above and to the left of this field of view, providing much of the radiation that powers the multi-coloured glow. Until recently, astronomers debated whether the source of the intense light was a tightly bound cluster of stars, or perhaps an unknown type of super-star thousands of times bigger than the Sun. It is only in the last 20 years, with the fine detail revealed by Hubble and the latest generation of ground-based telescopes, that astronomers have been able to conclusively prove that it is, indeed, a star cluster.

ESO - Pan across the Tarantula Nebula
But even if the Tarantula Nebula doesn’t contain this hypothetical super-star, it still hosts some extreme phenomena, making it a popular target for telescopes. Within the bright star cluster lies star RMC 136a1, which was recently found to be the heaviest ever discovered: the star's mass when it was born was around 300 times that of the Sun[1]. This heavyweight is challenging astronomers’ theories of star formation, smashing through the upper limit they thought existed on star mass.

Wide-field view of the Tarantula Nebula and its surroundings



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

Images Credits: NASA, ESA.


    * Images of Hubble:

Images, Text, Credits: NASA / ESA / Oli Usher / Videos: Hubble / Visual design and editing: Martin Kornmesser / Animations: Martin Kornmesser / Web and technical support: Lars Holm Nielsen and Raquel Yumi Shida / Written by: Oli Usher / Presented by: Joe Liske (Dr J) / Music: movetwo / Directed by: Oli Usher / Executive producer: Lars Lindberg Christensen / NASA, ESA, Digitised Sky Survey 2, R. Gendler, S. Brunier. Acknowledgement: Davide De Martin. Music by John Dyson.


dimanche 13 mars 2011

Japan Earthquake, Images from NASA's Earth Observatory, Actual Status of Dammaged Nuclear Plants

NASA - ASTER - EOS Terra Mission patch.

March 13, 2011

Smoke Plume from Industrial Fires in Miyagi Prefecture, Japan

In the aftermath of the massive earthquake that struck northeastern Japan at 2:46 p.m. local time on March 11, 2011, and its subsequent tsunami, several oil refineries and industrial complexes caught fire, including facilities in the Port of Sendai and a petrochemical facility in Shiogama, where a large explosion has been reported. This pair of images, acquired on March 12, 2011 by the Multi-angle Imaging SpectroRadiometer (MISR) instrument aboard NASA's Terra spacecraft, shows a large smoke plume that appears to be associated either with the Shiogama incident or the Sendai port fires. The presence of clouds makes it difficult to pinpoint the exact origin. The data were obtained at a local time of about 10:30 a.m.

The images are oriented with north at the left and east at the top, and cover an area measuring 85 kilometers by 115 kilometers (53 miles by 71 miles). The left-hand view is a natural-color image from MISR's nadir (vertical viewing) camera. The large brown smoke plume extends about 85 kilometers (53 miles) southeast from the coastline. To confirm that the brown plume is an airborne feature, the right-hand image is a stereoscopic "anaglyph" created from data in MISR's red spectral band, and generated by displaying the 46-degree backward view in red and 60-degree backward view in cyan. The separation between the red and cyan images is known as stereo parallax, and is related to the height of the observed features above the surface. Viewing the anaglyph with red-cyan glasses (red filter over the left eye) gives a perception of height. No separation is visible for the coastline, which is at sea level, but the clouds and plume are distinctly elevated. The height of the plume is estimated to be about 2 kilometers (1.2 miles), at a similar altitude as the nearby clouds.

Image, Text,  Credit: NASA /GSFC / LaRC/ JPL, MISR Team.

Current status of nuclear reactors damaged by the earthquake

Tokyo Electric Power Co. continues to implement emergency cooling and pressure relief operations at Fukushima Daiichi nuclear power station. In addition, at Fukushima Daini, three reactors remain shut down. They have electrical power available at Daini, but the suppression water pools used for reactor cooling are saturated at both sites.

The Fukushima Daiichi power plant's Unit 1 is seen after an explosion

Fukushima Daiichi: There is a state of emergency declared at Fukushima Daiichi 1, 2 and 3. The company is venting containment structures at reactors 1 and 3. Reactor 3 uses mixed-oxide fuel. Electrical power is not available at any of the reactors at this site and there is not backup power available at Units 1, 2 and 3. TEPCO has been pumping seawater into reactors 1 and 3 to maintain cooling and there is some uranium fuel rod damage suspected at both reactors. Public evacuation has been ordered and executed in a 12-mile radius and there have been low levels of radiation released into the environment as a result of venting and the explosion at Unit 1 secondary containment. The maximum reported dose at the site is 128 millirem per hour, which is less than the annual average dose for commercial airline flight crews and far less than the radiation the average American is exposed to per year from all sources (see the the U.S. Environmental Protection Agency's Web page on radiation protection). One worker at the site has received a radiation dose of 10.6 rem.

Schematic of Reactor Design at Fukushima Daiichi 1

Fukushima Daini: There is a state of emergency at Units 1, 2 and 4 and evacuation has been ordered and executed for 2.5 miles around the plant. There has been no radioactive release reported at the site. There is electric power available at all four reactors at the site, but there is limited use of cooling water pumps at Units 1, 2 and 4 due to damage from the tsunami. The suppression pools are saturated at all three reactors.

Comments from Japanese officials:

The company is providing seawater and boron for core cooling at Fukushima Daiichi units 1 and 3 and is venting containment at the reactors, Japan’s Chief Cabinet Secretary, Yukio Edano, said on Sunday. Officials are acting on the assumption that a meltdown could be underway at Fukushima Daiichi Unit 3. "Unlike the No.1 reactor, we ventilated and injected water at an early stage," Edano said.

Authorities are preparing to distribute iodine to protect people from radioactive exposure.

Images, Text, Credits: Nuclear Energy Institute / Reuters.

Related links:

the U.S. Environmental Protection Agency's Web page on radiation protection:

Tokyo Electric Power Co:

Nuclear Energy Institute:


This image of Japan from 1999 was taken as part of SeaWiFS, the Sea-viewing Wide Field-of-view Sensor Project. The SeaWiFS Mission, which was part of NASA's Earth Science Enterprise, was designed to look at our planet from space to better understand it as a system in both behavior and evolution.

Image, Text, Credit: NASA / Goddard Space Flight Center, SeaWiFS Project and ORBIMAGE.

Earthquake and Tsunami near Sendai, Japan

On March 11, 2011, at 2:46 p.m. local time (05:46 Universal Time, or UTC), a magnitude 8.9 earthquake struck off the east coast of Japan, at 38.3 degrees North latitude and 142.4 degrees East longitude. The epicenter was 130 kilometers (80 miles) east of Sendai, and 373 kilometers (231 miles) northeast of Tokyo. If the initial measurements are confirmed, it will be the world's fifth largest earthquake since 1900.

This map shows the location of the March 11 earthquake, as well as the foreshocks (dotted lines) and aftershocks (solid lines). The size of each circle represents the magnitude of the associated quake or shock. The map also includes land elevation data from NASA’s Shuttle Radar Topography Mission and ocean bathymetry data from the British Oceanographic Data Center.

According to the U.S. Geological Survey (USGS), the earthquake occurred at a depth of 24.4 kilometers (15.2 miles) beneath the seafloor. The March 11 earthquake was preceded by a series of large foreshocks on March 9, including an M7.2 event. USGS reported that the earthquakes “occurred as a result of thrust faulting on or near the subduction zone interface plate boundary.”

The March 11 quake sent tsunami waves rushing into the coast of Japan and rippling out across the entire Pacific basin. Crescent-shaped coasts and harbors, such as those near Sendai, can play a role in focusing the waves as they approach the shore. Also, the land elevation is low and flat along much of the Japanese coast west and south of the earthquake epicenter, leaving many areas particularly vulnerable to tsunamis.

The Japan Meteorological Agency reported maximum tsunami heights of 4.1 meters at Kamaishi at 3:21 p.m. (06:21 UTC), 7.3 meters at 3:50 p.m. (06:50 UTC) at the Soma station, and 4.2 meters at 4:52 p.m. (07:52 UTC) at Oarai.

The U.S. Pacific Tsunami Warning Center (PTWC) reported a wave with maximum height of 2.79 meters (9.2 feet) at an observing station at Hanasaki, Hokkaido, at 3:57 p.m. local time (06:57 UTC). Other PTWC reports of tsunami waves include:

1.27 meters (4.2 feet) at 10:48 UTC at Midway Island
1.74 meters (5.7 feet) at 13:72 UTC at Kahului, Maui, Hawaii
1.41 meters (4.6 feet) at 14:09 UTC at Hilo, Hawaii
0.69 meters (2.3 feet) at 15:42 UTC in Vanuatu
1.88 meters (6.2 feet) at 16:54 UTC at Port San Luis, California
2.02 meters (6.6 feet) at 16:57 UTC at Crescent City, California

NASA Earth Observatory image created by Robert Simmon and Jesse Allen, using earthquake and plate tectonics data from the USGS Earthquake Hazard Program, land elevation data from the Shuttle Radar Topography Mission (SRTM) provided by the University of Maryland’s Global Land Cover Facility, and ocean bathymetry data from the British Oceanographic Data Center’s Global Bathmetric Chart of the Oceans (GEBCO). Caption by Michael Carlowicz.

NASA Radar Image Shows Topography of Sendai, Japan Region

The topography of the earthquake and tsunami-stricken city of Sendai, Japan, is revealed in this radar image from NASA's Shuttle Radar Topography Mission. On March 11, 2011, a magnitude 8.9 earthquake struck offshore about 130 kilometers (80 miles) east of Sendai, the capital city of Japan's Miyagi Prefecture, generating a tsunami that devastated the low-lying coastal city of about 1 million residents.

This image combines a radar image acquired in February 2000 during the SRTM mission, and color-coding by topographic height using data from the same mission. Dark green colors indicate low elevations, rising through yellow and tan, to white at the highest elevations.

Image, Text, Credit: NASA /JPL / NGA.

More Imagery:

    * Images from NASA's Earth Observatory:

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