vendredi 21 octobre 2011

NASA Releases Visual Tour of Earth's Fires














NASA - Aqua Earth Observing System logo / NASA - EOS TERRA Mission patch.

Oct. 21, 2011

NASA has released a series of new satellite data visualizations that show tens of millions of fires detected worldwide from space since 2002. The visualizations show fire observations made by the MODerate Resolution Imaging Spectroradiometer, or MODIS, instruments onboard NASA's Terra and Aqua satellites.

NASA maintains a comprehensive research program using satellites, aircraft and ground resources to observe and analyze fires around the world. The research helps scientists understand how fire affects our environment on local, regional and global scales.

video

Video above: Fire observations from around the world taken over nearly 10 years are shown in this visualization of NASA satellite data. (Credit: NASA's Goddard Space Flight Center).

"What you see here is a very good representation of the satellite data scientists use to understand the global distribution of fires and to determine where and how fire distribution is responding to climate change and population growth," said Chris Justice of the University of Maryland, College Park, a scientist who leads NASA's effort to use MODIS data to study the world's fires.

One of the new visualizations takes viewers on a narrated global tour of fires detected between July 2002 and July 2011. The fire data is combined with satellite views of vegetation and snow cover to show how fires relate to seasonal changes. The Terra and Aqua satellites were launched in 1999 and 2002, respectively.

The tour begins by showing extensive grassland fires spreading across interior Australia and the eucalyptus forests in the northwestern and eastern part of the continent. The tour then shifts to Asia where large numbers of agricultural fires are visible first in China in June 2004, then across a huge swath of Europe and western Russia in August. It then moves across India and Southeast Asia, through the early part of 2005. The tour continues across Africa, South America, and concludes in North America.

The global fire data show that Africa has more abundant burning than any other continent. MODIS observations have shown that some 70 percent of the world's fires occur in Africa. During a fairly average burning season from July through September 2006, the visualizations show a huge outbreak of savanna fires in Central Africa driven mainly by agricultural activities, but also driven by lightning strikes.

Fires are comparatively rare in North America, making up just 2 percent of the world's burned area each year. The fires that receive the most attention in the United States -- the uncontrolled forest fires in the West -- are less visible than the wave of agricultural fires prominent in the Southeast and along the Mississippi River Valley. Some of the large wildfires that ravaged Texas this year are visible in the animation.

NASA maintains multiple satellite instruments capable of detecting fires and supports a wide range of fire-related research. Such efforts have yielded the most widely used data records of global fire activity and burned area in the world. NASA-supported scientists use the data to advance understanding about Earth's climate system, ecosystem health, and the global carbon cycle.

NASA's Applied Sciences Program seeks out innovative and practical benefits that result from studying fires. For example, the program has found ways to integrate space-based wildfire observations into air quality models used by the U.S. Environmental Protection Agency that help protect public health.

NASA will extend the United States' capability to monitor and study global fires from space with the launch this month of the National Polar-orbiting Operational Environmental Satellite System Preparatory Project. The satellite is the first mission designed to collect data to increase our understanding of long-term climate change and improve weather forecasts.

One of National Polar-orbiting Operational Environmental Satellite System Preparatory Project's new, state-of-the-art science instruments will provide scientists with data to extend the long-term global fires data record. The satellite is targeted to launch from Vandenberg Air Force Base in California on Oct. 28. The mission is managed by NASA's Goddard Space Flight Center in Greenbelt, Md., for the Earth Science Division of the Science Mission Directorate at NASA Headquarters in Washington.

MODIS data are processed by the MODIS Advanced Processing System at Goddard. The algorithm and product validation is done by scientists at the University of Maryland. The visualizations were created at Goddard's Scientific Visualization Studio. The fire, vegetation and snow data all come from the MODIS instruments on Terra and Aqua.

Videos focusing on continents:

Africa: http://svs.gsfc.nasa.gov/vis/a000000/a003800/a003870/index.html
Asia: http://svs.gsfc.nasa.gov/vis/a000000/a003800/a003869/index.html
Australia: http://svs.gsfc.nasa.gov/vis/a000000/a003800/a003871/index.html
N. America: http://svs.gsfc.nasa.gov/vis/a000000/a003800/a003873/index.html
S. America: http://svs.gsfc.nasa.gov/vis/a000000/a003800/a003872/index.html

Related Links:

A Look Back at a Decade of Fires: Feature Story and Additional Videos: http://www.nasa.gov/mission_pages/fires/main/modis-10.html

NASA's Fires and Smoke website: http://www.nasa.gov/fires

Video (mentioned), Text, Credit: NASA.

Cheers, Orbiter.ch

Liftoff! Soyuz begins its maiden mission from the Guiana Spaceport














ARIANESPACE - "Launches Speak Louder Than Words" patch / ESA - GALILEO logo.

October 21, 2011

Soyuz Flight VS01

Soyuz lift-off from French Guiana

Soyuz begins its first ascent from the Spaceport on today’s historic mission. In the foreground is the purpose-built mobile service gantry, which was moved back to its parked position one hour before Soyuz’ liftoff.

video
Launch of Galileo on Soyuz ST-B Flight VS01

The first Soyuz has lifted off from French Guiana, initiating a 3-hour 49-minute inaugural flight for Arianespace’s medium-lift launcher that will orbit the initial two spacecraft in Europe’s Galileo satellite navigation system.

Soyuz departed the Spaceport’s new ELS launch complex at 07:30:26 a.m. local time in French Guiana – a precise liftoff time that enables the pair of Galileo satellites to be injected into their proper orbital plane.

With a total payload performance of 1,580 kg. – including 700 kg. for each of the Galileo platforms – the Soyuz is to deliver its passengers into a 23,222-km. circular medium-Earth orbit, inclined 54.7 degrees.

Galileo IOV in orbit

This maiden flight marks Soyuz’ introduction into the company’s growing launcher family, joining its heavy-lift Ariane 5 in operations from the Spaceport.  The two launchers are to be complemented by the lightweight Vega in 2012.

Soyuz is one of the world’s most utilized launchers, having ushered in the space age and logging more than 1,770 missions to date from its two other launch bases: Baikonur Cosmodrome in Kazakhstan, and Russia’s Plesetsk Cosmodrome.

Related link:

Arianespace’s VS01 launch kit has additional details on this milestone mission: http://www.arianespace.com/news-launch-kits/2006-2010-archive.asp

ESA Navigation - Galileo: http://www.esa.int/esaNA/galileo.html

Images, Video, Text, Credits: ESA / S. Corvaja / Arianespace.

Greetings, Orbiter.ch

jeudi 20 octobre 2011

When Galaxies Collide












NASA - Hubble Space Telescope patch.

Oct. 20, 2011


This interacting pair of galaxies is included in Arp's catalog of peculiar galaxies as number 148. Arp 148 is the staggering aftermath of an encounter between two galaxies, resulting in a ring-shaped galaxy and a long-tailed companion. The collision between the two parent galaxies produced a shockwave effect that first drew matter into the center and then caused it to propagate outwards in a ring. The elongated companion perpendicular to the ring suggests that Arp 148 is a unique snapshot of an ongoing collision.

Infrared observations reveal a strong obscuration region that appears as a dark dust lane across the nucleus in optical light. Arp 148 is nicknamed Mayall's object and is located in the constellation of Ursa Major, the Great Bear, approximately 500 million light-years away.

This image is part of a large collection of 59 images of merging galaxies taken by the Hubble Space Telescope and released on April 24, 2008, the observatory's 18th anniversary.

NASA Hubble website: http://hubblesite.org/

ESA Hubble website: http://www.spacetelescope.org/

Image, Text, Credit: NASA, ESA, the Hubble Heritage (STScI / AURA)-ESA / Hubble Collaboration, and A. Evans (University of Virginia, Charlottesville / NRAO / Stony Brook University).

Greetings, Orbiter.ch

Herschel detects abundant water in planet-forming disc












ESA - Herschel Mission patch.

20 October 2011

ESA’s Herschel space observatory has found evidence of water vapour emanating from ice on dust grains in the disc around a young star, revealing a hidden ice reservoir the size of thousands of oceans.

TW Hydrae, a star between 5-10 million years old, and only 176 light-years away, is in the final stage of formation, and is surrounded by a disc of dust and gas that may condense to form a complete set of planets.

It is believed that a large proportion of Earth’s water may have come from ice-laden comets that bombarded our world during and after its formation. Recent studies of comet 103P/Hartley 2 with Herschel shed new light on how water may have come to Earth, with its findings of the first Earth-like water in a comet. Until now, however, almost nothing was known about reservoirs in planet-forming discs around other stars.

Detection of water vapour in the spectrum of TW Hydrae's protoplanetary disc

This new detection is the first of its kind and has been made possible by Herschel’s HIFI instrument.

The tell-tale water vapour signature, believed to be produced when the ice coated dust grains are warmed by interstellar UV radiation, has been detected throughout the disc around TW Hydrae, and, though weaker than expected, it hints at a substantial reservoir of ice. This could be a rich source of water for any planets that form around this young star.

"The detection of water sticking to dust grains throughout the disc would be similar to events in our own Solar System's evolution, where over millions of years, similar dust grains then coalesced to form comets," says Michiel Hogerheijde of Leiden University in the Netherlands, who led the study.

"These comets we believe became a contributing source of water for the planets."

The scientists ran detailed simulations, combining the new data with previous ground-based observations and some from NASA’s Spitzer telescope. From this they calculated the size of the ice reservoirs in the planet-forming regions.

Artist's impression of the TW Hydrae protoplanetary disc

Their results show that the total amount of water in the disc around TW Hydrae would fill several thousand Earth oceans.

"We already have approved time on Herschel to study more planet-forming regions around three other stars," says Dr Hogerheijde.

"We believe that will show similar results in terms of the water detections, but as our next observations will be of objects up to three times further in distance away, we'll need many more hours of observation time."

This research breaks new ground in understanding water’s role in planet-forming discs and gives scientists a new testing ground for looking at how water came to our own planet.

"With Herschel we can follow the trail of water through all the steps of star and planet formation," comments Göran Pilbratt, Herschel Project Scientist at ESA.

"Here we are studying the 'raw material' for planet formation, which is fundamental to an understanding of how planetary systems such as our own Solar System once formed."

Read more:

Observations: Seeing in infrared wavelengths: http://www.esa.int/esaSC/SEMS72T1VED_index_0.html

Why infrared astronomy is a hot topic: http://www.esa.int/esaCP/SEMX9PZO4HD_FeatureWeek_0.html

L2, the second Lagrangian Point: http://www.esa.int/esaSC/SEMO4QS1VED_index_0.html

In depth:

This story in depth: http://sci.esa.int/jump.cfm?oid=49488

Herschel in depth: http://sci.esa.int/science-e/www/area/index.cfm?fareaid=16

Images, Text, Credits: ESA / NASA / JPL-Caltech / M. Hogerheijde (Leiden Observatory).

Best regards, Orbiter.ch

Correction of the ISS orbit was nominally












ISS - International Space Station patch.

10/20/2011

October 19 carried out the planned correction of the orbit of the International Space Station. The maneuver was performed using vernier engine service module "Zvezda".

Correction of the orbit was nominally in accordance with the calculations of ballistic Service Mission Control Center Research Institute of mechanical engineering.

ISS

Following the correction of the ISS orbit parameters were as applied:

      ∙ minimum height above the Earth - 377.6 km;

      ∙ maximum height above the Earth's surface - 402.9 km;

      ∙ period - 92.26 minutes;

      ∙ inclination - 51.66 degrees.

The following correction of the ISS orbit is scheduled for October 26. The purpose of these exercises is to ensure optimal conditions for the flight to the station ships "Progress M-13M" and "Soyuz TMA-22" and the landing capsule "Soyuz TMA-02M" in a given area landing.

Original Text in Russian: http://www.federalspace.ru/main.php?id=2&nid=18096

Image, Text, Credits: Press-service of Federal Space Agency and PCOs (Roscosmos PAO) / Translation: Orbiter.ch.

Greetings, Orbiter.ch

mercredi 19 octobre 2011

Successful launch of Proton-M with the spacecraft Viasat-1















ILS - VIASAT-1 launch mission poster.


19/10/2011

Proton-M launch with the spacecraft Viasat-1

October 19 at 22 h. 48 min. Moscow with a launcher platform 39 200 Baikonur, by International Launch Services of Russia (ILS) conducted a successful launch of space rocket "Proton-M" with the upper stage "Breeze-M" spacecraft and "Viasat-1."

video
Proton-M launch with the spacecraft Viasat-1

This launch for "Proton" launch was the sixth in 2011 and the 369th start of his flight history.

After regular office from the third stage rocket upper stage "Breeze-M" spacecraft continues removing "Viasat-1" into the desired orbit.

Viasat-1 satellite

Separation of the spacecraft from the upper stage is scheduled for 8:00 min 01 GMT October 20, 2011

Press Service of the Russian Space Agency (Roscosmos PAO) / ILS / Translation: Orbiter.ch.

For more information about ILS, visit: http://www.ilslaunch.com/

Greetings, Orbiter.ch

NASA's Spitzer Detects Comet Storm in Nearby Solar System













NASA - SPITZER Space Telescope patch.

October 19, 2011


This artist's conception illustrates a storm of comets around a star near our own, called Eta Corvi. Evidence for this barrage comes from NASA's Spitzer Space Telescope, whose infrared detectors picked up indications that one or more comets was recently torn to shreds after colliding with a rocky body. Image credit: NASA / JPL-Caltech.

NASA's Spitzer Space Telescope has detected signs of icy bodies raining down in an alien solar system. The downpour resembles our own solar system several billion years ago during a period known as the "Late Heavy Bombardment," which may have brought water and other life-forming ingredients to Earth.

During this epoch, comets and other frosty objects that were flung from the outer solar system pummeled the inner planets. The barrage scarred our moon and produced large amounts of dust.

Now Spitzer has spotted a band of dust around a nearby bright star in the northern sky called Eta Corvi that strongly matches the contents of an obliterated giant comet. This dust is located close enough to Eta Corvi that Earth-like worlds could exist, suggesting a collision took place between a planet and one or more comets. The Eta Corvi system is approximately one billion years old, which researchers think is about the right age for such a hailstorm.

"We believe we have direct evidence for an ongoing Late Heavy Bombardment in the nearby star system Eta Corvi, occurring about the same time as in our solar system," said Carey Lisse, senior research scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., and lead author of a paper detailing the findings. The findings will be published in the Astrophysical Journal. Lisse presented the results at the Signposts of Planets meeting at NASA's Goddard Space Flight Center in Greenbelt, Md., today, Oct. 19.

Astronomers used Spitzer's infrared detectors to analyze the light coming from the dust around Eta Corvi. Certain chemical fingerprints were observed, including water ice, organics and rock, which indicate a giant comet source.

The light signature emitted by the dust around Eta Corvi also resembles the Almahata Sitta meteorite, which fell to Earth in fragments across Sudan in 2008. The similarities between the meteorite and the object obliterated in Eta Corvi imply a common birthplace in their respective solar systems.

A second, more massive ring of colder dust located at the far edge of the Eta Corvi system seems like the proper environment for a reservoir of cometary bodies. This bright ring, discovered in 2005, looms at about 150 times the distance from Eta Corvi as the Earth is from the sun. Our solar system has a similar region, known as the Kuiper Belt, where icy and rocky leftovers from planet formation linger. The new Spitzer data suggest that the Almahata Sitta meteorite may have originated in our own Kuiper Belt.

The Kuiper Belt was home to a vastly greater number of these frozen bodies, collectively dubbed Kuiper Belt objects. About 4 billion years ago, some 600 million years after our solar system formed, scientists think the Kuiper Belt was disturbed by a migration of the gas-giant planets Jupiter and Saturn. This jarring shift in the solar system's gravitational balance scattered the icy bodies in the Kuiper Belt, flinging the vast majority into interstellar space and producing cold dust in the belt. Some Kuiper Belt objects, however, were set on paths that crossed the orbits of the inner planets.

The resulting bombardment of comets lasted until 3.8 billion years ago. After comets impacted the side of the moon that faces Earth, magma seeped out of the lunar crust, eventually cooling into dark "seas," or maria. When viewed against the lighter surrounding areas of the lunar surface, those seas form the distinctive "Man in the Moon" visage. Comets also struck Earth or incinerated in the atmosphere, and are thought to have deposited water and carbon on our planet. This period of impacts might have helped life form by delivering its crucial ingredients.

"We think the Eta Corvi system should be studied in detail to learn more about the rain of impacting comets and other objects that may have started life on our own planet," Lisse said.

NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages the Spitzer mission for the agency's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

For more information about Spitzer, visit http://spitzer.caltech.edu/ and http://www.nasa.gov/spitzer .

Image, Text, Credit: NASA / JPL / Whitney Clavin / Trent J. Perrotto.

Greetings, Orbiter.ch

VISTA Finds New Globular Star Clusters...












ESO - European Southern Observatory logo.

19 October 2011

...and sees right through the heart of the Milky Way

VISTA view of the newly discovered globular cluster VVV CL001 and its brighter companion

Two newly discovered globular clusters have been added to the total of just 158 known globular clusters in our Milky Way. They were found in new images from ESO’s VISTA survey telescope as part of the Via Lactea (VVV) survey. This survey has also turned up the first star cluster that is far beyond the centre of the Milky Way and whose light has had to travel right through the dust and gas in the heart of our galaxy to get to us.

VISTA view of the newly discovered globular cluster VVV CL002 close to the centre of the Milky Way

The dazzling globular cluster called UKS 1 dominates the right-hand side of the first of the new infrared images from ESO’s VISTA survey telescope at the Paranal Observatory in Chile. But if you can drag your gaze away, there is a surprise lurking in this very rich star field — a fainter globular cluster that was discovered in the data from one of VISTA’s surveys. You will have to look closely to see the other star cluster, which is called VVV CL001: it is a small collection of stars in the left half of the image.

VISTA view of the newly discovered open star cluster VVV CL003 beyond the galactic centre

But VVV CL001 is just the first of VISTA’s globular discoveries. The same team has found a second object, dubbed VVV CL002, which appears in image b [1]. This small and faint grouping may also be the globular cluster that is the closest known to the centre of the Milky Way. The discovery of a new globular cluster in our Milky Way is very rare. The last one was discovered in 2010, and only 158 globular clusters were known in our galaxy before the new discoveries.

Visible/infrared comparison views of the newly discovered globular cluster VVV CL001

These new clusters are early discoveries from the VISTA Variables in the Via Lactea (VVV) survey that is systematically studying the central parts of the Milky Way in infrared light. The VVV team is led by Dante Minniti (Pontificia Universidad Católica de Chile) and Philip Lucas (Centre for Astrophysics Research, University of Hertfordshire, UK).

Wide-field view of the newly discovered globular cluster VVV CL001

As well as globular clusters, VISTA is finding many open, or galactic clusters, which generally contain fewer, younger, stars than globular clusters and are far more common (eso1128). Another newly announced cluster, VVV CL003, seems to be an open cluster that lies in the direction of the heart of the Milky Way, but much further away, about 15 000 light-years beyond the centre. This is the first such cluster to be discovered on the far side of the Milky Way.

video
Zooming in on the newly discovered globular star cluster VVV CL001

Given the faintness of the newly found clusters, it is no wonder that they have remained hidden for so long; up until a few years ago, UKS 1 (seen in image a), which easily outshines the newcomers, was actually the dimmest known globular cluster in the Milky Way. Because of the absorption and reddening of starlight by interstellar dust, these objects can only be seen in infrared light and VISTA, the world’s largest survey telescope, is ideally suited to searching for new clusters hidden behind dust in the central parts of the Milky Way [2].

One intriguing possibility is that VVV CL001 is gravitationally bound to UKS 1 — making these two stellar groups the Milky Way’s first binary globular cluster pair. But this could just be a line-of-sight effect with the clusters actually separated by a vast distance.

video
Visible/infrared cross-fade of the newly discovered globular star cluster VVV CL001

These VISTA pictures were created from images taken though near-infrared filters J (shown in blue), H (shown in green), and Ks (shown in red). The size of the images show only a small fraction of the full VISTA field of view.

Notes:

[1] The discovery of the additional new clusters was just announced in San Juan, Argentina, during the first bi-national meeting of the Argentinian and Chilean astronomical associations.

[2] The tiny dust grains that form huge clouds within galaxies scatter blue light much more strongly than red and infrared light. As a result astronomers can see through the dust much more effectively if they study infrared light rather than the usual visible radiation that our eyes are sensitive to.

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 two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 40-metre-class European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Links:

    Associated research papers: A&A papers (Minniti et al A&A, 527, 81 & Moni Bidin et al. astro-ph:1109.1854):  http://www.eso.org/public/archives/releases/sciencepapers/eso1141/eso1141a.pdf

http://www.eso.org/public/archives/releases/sciencepapers/eso1141/eso1141b.pdf

    Photos of VISTA: http://www.eso.org/public/images/archive/search/?category=1111&adv=&title=VISTA

Images, Text, Credits: ESO / D. Minniti / VVV Team / Digitized Sky Survey 2. Acknowledgement: Davide De Martin / Maren Hempel / Christian Moni Bidin / Richard Hook / Videos: ESO / D. Minniti / VVV Team / S. Brunier / S. Guisard / Digitized Sky Survey 2. Music: John Dyson (from the album Moonwind).

Best regards, Orbiter.ch

mardi 18 octobre 2011

Swirling Landscape of Stars








NASA - SPITZER Space Telescope logo.

Oct. 18, 2011


This swirling landscape of stars is known as the North America Nebula. In visible light, the region resembles North America, but in this image infrared view from NASA's Spitzer Space Telescope, the continent disappears.

Where did the continent go? The reason you don't see it in Spitzer's view has to do, in part, with the fact that infrared light can penetrate dust whereas visible light cannot. Dusty, dark clouds in the visible image become transparent in Spitzer's view. In addition, Spitzer's infrared detectors pick up the glow of dusty cocoons enveloping baby stars.

Clusters of young stars (about one million years old) can be found throughout the image. Some areas of this nebula are still very thick with dust and appear dark even in Spitzer's view.

The Spitzer image contains data from both its infrared array camera and multi-band imaging photometer. Light with a wavelength of 3.6 microns has been color-coded blue; 4.5-micron light is blue-green; 5.8-micron and 8.0-micron light are green; and 24-micron light is red. This image is from February 2011.

For more information about SPITZER Space Telescope, visit: http://www.spitzer.caltech.edu/

Image, Text,  Credit: NASA / JPL-Caltech.

Greetings, Orbiter.ch

NASA, Japan Release Improved Topographic Map of Earth












NASA- EOS / TERRA Mission patch labeled.

Oct. 18, 2011

video

This flyover of the Hawaiian island of Oahu was made by draping Jan. 13, 2010, image data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft over new ASTER Version 2 digital elevation data.

NASA and Japan released a significantly improved version of the most complete digital topographic map of Earth on Monday, produced with detailed measurements from NASA's Terra spacecraft.

The map, known as a global digital elevation model, was created from images collected by the Japanese Advanced Spaceborne Thermal Emission and Reflection Radiometer, or ASTER, instrument aboard Terra. So-called stereo-pair images are produced by merging two slightly offset two-dimensional images to create the three-dimensional effect of depth. The first version of the map was released by NASA and Japan's Ministry of Economy, Trade and Industry (METI) in June 2009.


Image above: At 14,505 feet (4,421 meters) in elevation, California's Mt. Whitney, located in the Sierra Nevada Mountains on the west side of Owens Valley, is the highest point in the contiguous United States. Image credit: NASA / GSFC / METI / ERSDAC / JAROS, and U.S. / Japan ASTER Science Team.

"The ASTER global digital elevation model was already the most complete, consistent global topographic map in the world," said Woody Turner, ASTER program scientist at NASA Headquarters in Washington. "With these enhancements, its resolution is in many respects comparable to the U.S. data from NASA's Shuttle Radar Topography Mission, while covering more of the globe."

The improved version of the map adds 260,000 additional stereo-pair images to improve coverage. It features improved spatial resolution, increased horizontal and vertical accuracy, more realistic coverage over water bodies and the ability to identify lakes as small as 0.6 miles (1 kilometer) in diameter. The map is available online to users everywhere at no cost.


Image above: Arguably one of America's most magnificent national parks is the Grand Canyon in northern Arizona. Image credit: NASA / GSFC / METI / ERSDAC / JAROS, and U.S. / Japan ASTER Science Team.

"This updated version of the ASTER global digital elevation model provides civilian users with the highest-resolution global topography data available," said Mike Abrams, ASTER science team leader at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "These data can be used for a broad range of applications, from planning highways and protecting lands with cultural or environmental significance, to searching for natural resources."

The ASTER data cover 99 percent of Earth's landmass and span from 83 degrees north latitude to 83 degrees south. Each elevation measurement point in the data is 98 feet (30 meters) apart.

NASA and METI are jointly contributing the data for the ASTER topographic map to the Group on Earth Observations, an international partnership headquartered at the World Meteorological Organization in Geneva, Switzerland, for use in its Global Earth Observation System of Systems. This "system of systems" is a collaborative, international effort to share and integrate Earth observation data from many different instruments and systems to help monitor and forecast global environmental changes.


Image above: The Advanced Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft provided this spacebird's-eye view of the eastern part of Grand Canyon National Park in northern Arizona in this image, acquired July 14, 2011. Image credit: NASA / GSFC / METI / ERSDAC / JAROS, and U.S. / Japan ASTER Science Team.

ASTER is one of five instruments launched on Terra in 1999. ASTER acquires images from visible to thermal infrared wavelengths, with spatial resolutions ranging from about 50 to 300 feet (15 to 90 meters). A joint science team from the United States and Japan validates and calibrates the instrument and data products. The U.S. science team is located at JPL.

NASA, METI, Japan's Earth Remote Sensing Data Analysis Center (ERSDAC), and the U.S. Geological Survey validated the data, with support from the U.S. National Geospatial-Intelligence Agency and other collaborators. The data are distributed by NASA's Land Processes Distributed Active Archive Center at the U.S. Geological Survey's Earth Resources Observation and Science Center in Sioux Falls, S.D., and by ERSDAC in Tokyo.

Users of the new version of the ASTER data products are advised that while improved, the data still contain anomalies and artifacts that will affect its usefulness for certain applications.

Data users can download the ASTER global digital elevation model at: https://lpdaac.usgs.gov/ or http://www.ersdac.or.jp/GDEM/E/4.html .

For more information about ASTER, visit: http://asterweb.jpl.nasa.gov/ . For more information on NASA's Terra mission, visit: http://www.nasa.gov/terra .

JPL is managed for NASA by the California Institute of Technology in Pasadena.

Images (mentioned), Video (mentioned), Text, Credit: NASA / JPL / Alan Buis.

Best regards, Orbiter.ch

Stars Adorn Orion's Sword












NASA - SPITZER Space Telescope patch.

Oct. 18, 2011

 (Click on the image for enlarge)

This image from NASA's Spitzer Space Telescope shows what lies near the sword of the constellation Orion -- an active stellar nursery containing thousands of young stars and developing protostars. Many will turn out like our sun. Some are even more massive. These massive stars light up the Orion nebula, which is seen here as the bright region near the center of the image.

For more information about SPITZER Space Telescope, visit: http://www.spitzer.caltech.edu/

Image, Text, Credit: NASA / JPL-Caltech.

Cheers, Orbiter.ch

lundi 17 octobre 2011

CryoSat rocking and rolling







ESA - CryoSat 2 logo.

17 October 2011

ESA’s ice satellite is rolling left and right in orbit to help it continue its precise measurements of the vast ice sheets that blanket Greenland and Antarctica.

Since its launch 18 months ago, CryoSat-2 has been collecting data to improve our understanding of the relationship between ice and climate.

Just this year, the first map of Arctic sea-ice thickness was unveiled, and the satellite will continue to monitor the changing ice for years to come.

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CryoSat rocks and rolls

To ensure the precision of the measurements, an operation is under way to roll the satellite from side to side as it flies over the flat oceans.

This manoeuvre is to calibrate CryoSat’s radar altimeter for measuring ice thickness, especially over the margins of ice sheets.

The altimeter has two antennas mounted on a bench about a metre apart. When it is working in the ‘SARIn’ mode, both antennas are used in parallel: one emits a signal and both receive the signals that bounce back.

Normally, this bench is parallel to Earth’s surface. But at the edges of the ice sheets, the ice surface is not always flat and the slopes affect the return signals.

Measuring the freeboard of sea ice

Harsh conditions in space – with huge temperature differences between Sun and shade – can lead to the deterioration of CryoSat’s instruments, which can also lead to measurement errors.

In order to quantify these errors, ESA ground controllers are working to recalibrate the altimeter.

They are rolling the satellite to simulate the ice slopes and holding it in this position for several minutes. This must be done while CryoSat is over large, flat surfaces. For satellite altimeters, oceans are Earth’s largest flat surfaces.

It will also check whether errors are related to CryoSat’s varying thermal conditions – like when exposed to the Sun or in the shade.

“With the results from the different sets of rolls over different ocean surfaces and at different ambient conditions, we are aiming to characterise the instrument to a precision better than we thought we could make at the time of the launch,” said Tommaso Parrinello, CryoSat mission manager.

Arctic sea-ice thickness

During several manoeuvres on Monday and Tuesday, the satellite is rolling 0.4º to both sides while over the Indian and Pacific oceans, before returning to its original position.

“The preparations for the roll activities have been quite challenging,” explained Nic Mardle, spacecraft operations manager.

“Although we had experience of these activities from the commissioning phase, we had to iterate a few more times with the planning and mission control teams so that we could support exactly what was required.”

The complex calibration is a joint effort between ESA’s ESRIN centre for Earth observation in Italy and its ESOC operations centre in Germany.

CryoSat is dedicated to monitoring changes in the thickness of marine ice floating in the polar oceans and of the vast ice sheets that extend over Greenland and the Antarctic.

Satellites have already shown that the extent of sea ice in the Arctic is diminishing. In fact, this year’s minimum has set a new record low.

Related links:

CryoSat: http://www.esa.int/SPECIALS/Cryosat/index.html

Access CryoSat data: http://earth.esa.int/cryosat

ESRIN: http://www.esa.int/SPECIALS/ESRIN_SITE/index.html

ESOC: http://www.esa.int/SPECIALS/ESOC/index.html

Images, Animation, Text, Credits: ESA / M. Pinol (ESTEC) / AOES Medialab / CPOM / UCL.

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