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Rome, Italy

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Rome, Italy
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News Article | April 21, 2017
Site: www.cnet.com

When we look up and see planets from Earth, they appear as pinpoints of light. NASA's Cassini spacecraft peered between the rings of Saturn, gazed back at its home planet and captured a poignant image of Earth from 870 million miles (1.4 billion kilometers) away. From that distance, Earth appears as a glowing dot standing out in the darkness. Cassini snapped the image on April 12. "Although far too small to be visible in the image, the part of Earth facing Cassini at the time was the southern Atlantic Ocean," NASA says. The space agency also released a closer-up, cropped version of the photo in which the moon is visible as a fainter speck of light. We have to enjoy these new Cassini images while we can. The spacecraft is destined to destroy itself in Saturn's atmosphere later this year after a productive mission spent studying the ringed planet and its many moons. Cassini, a joint project from NASA, the European Space Agency and the Italian Space Agency, launched back in 1997. Its unique perspective on our solar system will be missed.


News Article | April 17, 2017
Site: www.cnet.com

A windy day on Earth is no comparison to a windy day on Saturn. The ringed planet is home to terrifying winds that can top 1,100 mph (1,800 kph). NASA describes them as "some of the fastest in the solar system." A Cassini image released Monday shows what those winds do to Saturn's atmosphere. Cassini sneaked a peek through the gas giant's hazy outer region by imaging the planet at infrared wavelengths. NASA poetically notes "the high-speed winds of Saturn's atmosphere produce watercolor-like patterns." Cassini snapped the image in December at a distance of 592,000 miles (953,000 kilometers) from Saturn. The spacecraft, a joint project from NASA, European Space Agency and the Italian Space Agency, launched in 1997 and is due to end its mission later this year by plunging into Saturn's atmosphere.


News Article | April 25, 2017
Site: news.yahoo.com

The Cassini spacecraft made its final flyby of Saturn’s largest moon Titan in the early hours of Saturday, and images it captured of the stellar body were released Monday by NASA and the European Space Agency. The spacecraft, which has been studying the Saturn system since 2004, will start its Grand Finale mission Wednesday and end it by plunging into the planet’s atmosphere Sept. 15. The last close flyby of Titan happened at 2:08 a.m. EDT Saturday, when Cassini was 979 kilometers (608 miles) above the moon’s surface. Among the data it transmitted to Earth over the last few days are radar images of the hydrocarbon seas and lakes covering the planet-sized moon’s north polar region. “Cassini’s up-close exploration of Titan is now behind us, but the rich volume of data the spacecraft has collected will fuel scientific study for decades to come,” Linda Spilker, the mission’s project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, said in a statement Monday. Using Titan’s gravity as a slingshot, Cassini is now moving into position for its last mission, the Grand Finale, during which it will make 22 dives — one each week — through the rings of Saturn, as well as the gas giant’s inner rings and its atmosphere. The first of these dives takes place Wednesday. Before the mission finally comes to an end, Cassini will make a last, distant flyby of Titan on Sept. 11, a maneuver that will ensure the spacecraft doesn’t crash into Enceladus, an ocean-moon of Saturn that is potentially habitable. Another image released Monday by NASA shows a massive canyon on Tethys, another of Saturn’s 63 known moons. The Ithaca Chasm is up to 60 miles wide and about 660 miles long, which is almost three-fourths of the icy moon’s surface. The maximum depth of the rift is about 2.4 miles, according to a statement that accompanied the image. Cassini is a collaboration between NASA, the European Space Agency and the Italian Space Agency. The European Geosciences Union will hold a press conference at 1:30 p.m. GMT (9:30 a.m. EDT) Tuesday to preview the Grand Finale and to talk about some of Cassini’s many achievements over the past 13 years. The press conference, being held in Vienna, can be watched live here.


Ground control points (GCPs) are points on the Earth's surface that can be used to geo-reference remote sensing satellite data. The identification of GCPs can be achieved either by on-ground inspections or by processing of aerial/satellite data. The first option ensures the highest geolocation accuracy, but it can require long turnaround times and high logistical costs. Moreover, in situ inspections can be impossible in certain areas of the world (e.g., because of difficult access or geopolitical issues). Hence, there is a strategic interest in the development of services that can be used to deliver accurate remote sensing of GCPs. Ongoing satellite missions—such as the Constellation of Small Satellites for Mediterranean Basin Observation (COSMO-SkyMed, or CSK) and TerraSAR-X (TSX)—are providing high-resolution synthetic aperture radar (SAR) data in the X-band (i.e., a segment of the microwave radio spectrum used for communications). The availability of this data is fostering the development of methods and services for extracting GCPs with sub-metric accuracy. Such endeavors are also appealing for both civilian and military purposes. Conceptually, SAR-based GCP-extraction consists of two steps. First, the same local feature is identified in a number of SAR images and its range/azimuth coordinates are determined. The second step involves the use of spatial triangulation (stereo analysis) and inversion methods for spatial 3D position retrieval from the 2D radar coordinates (range/azimuth). To boost the geolocation accuracy, SAR images must be acquired from different lines of sight, with intersection angles typically much wider than 10°. The lines of sight can even be in completely opposite directions,1 but this usually hinders the ability to perform the GCP identification in a fully automatic manner. In addition, many robust algorithms—such as the Scale-Invariant Feature Transform (SIFT), Speeded Up Robust Features, and Binary Robust Independent Elementary Features methods—have been proposed for the automatic identification and matching of local invariant features.2 These algorithms, however, were originally developed for optical photographs and images, and do not perform well on images affected by multiplicative noise sources (e.g., speckle in SAR data). To mitigate the effect of speckle noise, many adaptations of local-features-matching algorithms have thus been proposed in the recent literature, including SAR-SIFT3 and SIFT-Octave.4 These algorithms, however, only have satisfactory performances with narrow intersection angles. In this study,5 we propose a further adaptation to the existing algorithms. Our approach is specifically designed to ensure robustness and accuracy in the fully automatic detection of bright isolated targets (e.g., steel light poles or towers), even when dealing with opposite-side-looking data. In particular, we have selected the popular Harris algorithm6 as the detector. We chose this algorithm because recent studies4, 7 provide a consensus that it is the most stable and robust-to-noise algorithm for corner detections from SAR images. Furthermore, we opted for a solution that combines simplicity and robustness. This is different from previously proposed descriptors, which typically consist of high-dimension feature vectors (e.g., 128 for SIFT). We derive the properties of our descriptor from radar fragments centered on the candidate GCP corner. We also perform mild geocoding, through the use of low-resolution digital terrain models (DTMs) that are available over the area of interest (e.g., the Shuttle Radar Topography Mission or radargrammetric DTMs). In addition, the performance of our matching algorithm can be enhanced by limiting the search space (as demonstrated by previously proposed solutions, in which DTM and orbit information are used7 or that involve a manual pre-registration8). Once we have identified the GCP candidates and have estimated their fractional line/pixel coordinates from each SAR image, it is necessary to convert those coordinates into sensor–target distances and azimuth coordinates. In our approach, we must also account for the atmospheric propagation delay (APD)—i.e., delays in satellite-to-Earth communications caused by the atmosphere—for computation of the slanted range distance. We thus use numerical weather modeling9 to precisely estimate the APD. In the final part of our technique, we invert range/Doppler equations to infer the 3D geographic coordinates of the candidate GCPs. To improve the accuracy and confidence level, we use multiple scenes (with different look-angles) and we use the least-squares method to solve the over-determined system of equations. Although automatic GCP-extraction tools have previously been successfully verified on TSX data,10 such methods have not yet been tested on CSK images. We have therefore focused on assessing the performance of our algorithm for the processing of CSK data. According to the results from our earlier study,11 a preliminary timing recalibration is required for CSK images. This step is necessary for removing systematic geolocation biases in both range and azimuth directions. In this work, we conducted our experimental analysis for the Pisa area (Italy), for which consistent data takes of radargrammetric enhanced spotlight images are available in the CSK archive. An example of a GCP, in the Pisa urban area, which we automatically detected with our algorithm is shown in Figure 1. The outcomes of our analyses prove that our designed tool is capable of automatically identifying GCPs from CSK data and estimating their geographic position with sub-metric accuracy. In addition, as part of a differential global positioning system campaign, we have computed geolocation errors for a number of vertical isolated targets. In summary, we have developed a new algorithm for the automatic detection of ground control points in remotely sensed SAR datasets. We have based our tool on the popular Harris algorithm, and have thus designed a simple, robust, and accurate algorithm. We have also successfully tested our approach on data from the COSMO-SkyMed satellite for an urban area and have verified that it can be used to estimate the geolocation of GCPs, with sub-metric accuracy. In the next stage of our work we will assess the performance of the tool over mountainous areas, i.e., where radar image distortions are expected to hinder the visibility of GCPs (depending on the orientation of the slopes and the viewing geometry of the satellite sensors). This study was carried out within the framework of the 3D IMINT project (PRNM Contract 10444, 30-12-2013). CSK products, under a license from the Italian Space Agency, were used for this project.


News Article | April 27, 2017
Site: www.cnet.com

The Saturn-studying Cassini spacecraft triumphed through its first daring dive between the planet and its famous rings on Wednesday. The craft shot through the narrow gap and came within 1,900 miles (3,000 kilometers) of Saturn's clouds. "No spacecraft has ever been this close to Saturn before," Cassini Project Manager Earl Maize of NASA said. "We could only rely on predictions, based on our experience with Saturn's other rings, of what we thought this gap between the rings and Saturn would be like." Maize added that Cassini came through "in excellent shape." On Thursday, NASA released several unprocessed images captured during the flight, which give us our closest-ever view of Saturn's atmosphere. NASA had been confident Cassini would make it through the first historic dive but took the precaution of aiming the spacecraft's dish-like high-gain antenna to act as a shield against ring particles. This also created a situation in which Cassini was out of contact with mission control for a while. Cassini is scheduled to conduct a total of 22 close flybys for its "grand finale." The next will occur on May 2. The spacecraft will ultimately dive to its doom in Saturn's atmosphere in September. The mission, which launched in 1997, is a joint project of NASA, the European Space Agency and the Italian Space Agency. Batteries Not Included: The CNET team reminds us why tech is cool. CNET Magazine: Check out a sample of the stories in CNET's newsstand edition.


News Article | April 27, 2017
Site: news.yahoo.com

NASA's Cassini spacecraft captured this image of features in Saturn's atmosphere from closer than ever before (AFP Photo/Handout) Miami (AFP) - An unmanned NASA spacecraft has survived its plunge between the rings of Saturn and, after briefly going dark for the flyby, is communicating again with Earth, the US space agency said Thursday. Cassini skimmed closer than any previous spacecraft to the sixth planet from the Sun, and lived to tell the tale, sending back a signal that arrived early Thursday at 0656 GMT, about 20 hours after the crossing took place. "No spacecraft has ever been this close to Saturn before. We could only rely on predictions, based on our experience with Saturn's other rings, of what we thought this gap between the rings and Saturn would be like," said Cassini project manager Earl Maize of NASA's Jet Propulsion Laboratory in Pasadena, California. "I am delighted to report that Cassini shot through the gap just as we planned and has come out the other side in excellent shape." For more news videos visit Yahoo View, available now on iOS and Android. The gap between the rings and the top of Saturn's atmosphere is about 1,500 miles (2,400 kilometers) wide. The rings are made of fast-moving particles of ice and space debris that could strike and disable the spacecraft. Cassini zipped through at a speed of about 77,000 miles per hour relative to the planet. The spacecraft will make a total of 22 dives between the rings and the planet before making a death plunge into the gas giant in September. Its next pass is scheduled for May 2. The spacecraft is a joint mission of NASA, the European Space Agency and the Italian Space Agency. It launched in 1997 and has been orbiting Saturn since 2004. Cassini is now running low on fuel and scientists have decided to end its mission rather than risk damaging one of Saturn's moons, whose subsurface oceans may be explored for signs of life in the future.


News Article | May 2, 2017
Site: www.cnet.com

The Cassini spacecraft isn't going quietly into that good night. The mission's final days involve the probe taking 22 daring dives between Saturn and its rings. The first took place on April 26. On Monday, NASA reported a surprising discovery from that dive's data: it's really empty between the planet and the rings. NASA says its scientists are "puzzled" that the area is pretty much free from dust. Researchers converted data from one of Cassini's instruments into audio in order to listen for sounds of dust particles hitting the spacecraft, but heard very little evidence of impacts. "It was a bit disorienting -- we weren't hearing what we expected to hear," said Cassini team member William Kurth. "I've listened to our data from the first dive several times and I can probably count on my hands the number of dust particle impacts I hear." The gap between Saturn and its rings is just 1,200 miles (2,000 kilometers) wide. The planet's rings consist of ice and rock particles. Images of the gap led NASA scientists to believe it is clear of large particles that could damage Cassini, but they expected more dust than was found. Before the first dive, mission control oriented Cassini's large main antenna dish to protect it from debris, which turned out to be an unnecessary precaution. "The region between the rings and Saturn is 'the big empty,' apparently," said Cassini project manager Earl Maize. Cassini's next dive is scheduled for Tuesday. The spacecraft will be out of contact for a period of time during the dive, but should get back in touch with Earth on Wednesday to transmit data. The Cassini mission launched in 1997 as a joint project from NASA, the European Space Agency and the Italian Space Agency. The spacecraft is scheduled to destroy itself in Saturn's atmosphere in September. Does the Mac still matter? Apple execs tell why the MacBook Pro was over four years in the making, and why we should care. Solving for XX: The industry seeks to overcome outdated ideas about "women in tech."


San Antonio - April 13, 2017 - Scientists from Southwest Research Institute (SwRI) have discovered hydrogen gas in the plume of material erupting from Saturn's moon Enceladus. Analysis of data from NASA's Cassini spacecraft indicates that the hydrogen is best explained by chemical reactions between the moon's rocky core and warm water from its subsurface ocean. The SwRI-led team's discovery suggests that Enceladus' ocean floor could include features analogous to hydrothermal vents on Earth, which are known to support life on the seafloor. "Hydrogen is a source of chemical energy for microbes that live in the Earth's oceans near hydrothermal vents," said SwRI's Dr. Hunter Waite, principal investigator of Cassini's Ion Neutral Mass Spectrometer (INMS). "Our results indicate the same chemical energy source is present in the ocean of Enceladus. We have not found evidence of the presence of microbial life in the ocean of Enceladus, but the discovery of hydrogen gas and the evidence for ongoing hydrothermal activity offer a tantalizing suggestion that habitable conditions could exist beneath the moon's icy crust." Waite is the lead author of "Cassini Finds Molecular Hydrogen in the Enceladus Plume: Evidence for Hydrothermal Processes," published in the April 14, 2017, issue of the journal Science. On the Earth's ocean floor, hydrothermal vents emit hot, mineral-laden fluid, allowing unique ecosystems teeming with unusual creatures to thrive. Microbes that convert mineral-laden fluid into metabolic energy make these ecosystems possible. "The amount of molecular hydrogen we detected is high enough to support microbes similar to those that live near hydrothermal vents on Earth," said SwRI's Dr. Christopher Glein, a co-author on the paper and a pioneer of extraterrestrial chemical oceanography. "If similar organisms are present in Enceladus, they could 'burn' the hydrogen to obtain energy for chemosynthesis, which could conceivably serve as a foundation for a larger ecosystem." During Cassini's close flyby of Enceladus on Oct. 28, 2015, INMS detected molecular hydrogen as the spacecraft flew through the plume of gas and ice grains spewing from cracks on the surface. Previous flybys provided evidence for a global subsurface ocean residing above a rocky core. Molecular hydrogen in the plumes could serve as a marker for hydrothermal processes, which could provide the chemical energy necessary to support life. To search for hydrogen specifically native to Enceladus, the spacecraft flew particularly close to the surface and operated INMS in a specific mode to minimize and quantify any spurious sources. "We developed new operations methods for INMS for Cassini's final flight through Enceladus' plume," said SwRI's Rebecca Perryman, the INMS operations technical lead. "We conducted extensive simulations, data analyses, and laboratory tests to identify background sources of hydrogen, allowing us to quantify just how much molecular hydrogen was truly originating from Enceladus itself." Scientists also considered other sources of hydrogen from the moon itself, such as a preexisting reservoir in the ice shell or global ocean. Analysis determined that it was unlikely that the observed hydrogen was acquired during the formation of Enceladus or from other processes on the moon's surface or in the interior. "Everything indicates that the hydrogen originates in the moon's rocky core," Waite said. "We considered various ways hydrogen could leach from the rock and found that the most plausible source is ongoing hydrothermal reactions of rock containing reduced minerals and organic materials." INMS, built by NASA's Goddard Space Flight Center, is operated by an international team of scientists headed by Waite. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, Pasadena, California, a division of Caltech, manages the mission for NASA's Science Mission Directorate in Washington, D.C. The Cassini orbiter was designed, developed, and assembled at JPL.


News Article | May 25, 2017
Site: www.cnet.com

Saturn has pulled off an even more extreme color-changing trick than Starbucks managed with its Unicorn Frappuccino. NASA released a set of images on Wednesday showing how the planet's north polar region shifted from light blue colors in June 2013 to yellow hues by April 2017. The hexagonal jet stream system is one of Saturn's most distinctive features (along with its trademark rings). NASA's Cassini spacecraft snapped these views, which NASA presents side-by-side in natural color to show how much Saturn has changed its decor over the years. NASA believes the yellowish haze comes from smog particles caused by an increase in solar radiation. Saturn's northern summer solstice arrived on Wednesday, an event that happens roughly every 15 Earth years. Despite the dramatic color differences across most of the region, the central polar vortex remains blue. Scientists think this quirk could be due to a lack of sunlight reaching that specific area. "A second explanation hypothesizes that the polar vortex may have an internal circulation similar to hurricanes on Earth," NASA says. If that's true, any smog particles may be forced downward and out of sight. Cassini is currently engaged in a "Grand Finale" tour of Saturn, where it's flying close to the planet by squeaking past its rings. The spacecraft, a joint project from NASA, the European Space Agency and the Italian Space Agency, is scheduled to destroy itself by diving in Saturn's atmosphere in September. CNET en Español: Get all your tech news and reviews in Spanish. Does the Mac still matter? Apple execs tell why the MacBook Pro was over four years in the making, and why we should care.


News Article | May 10, 2017
Site: www.cnet.com

The Cassinis spacecraft's farewell tour of Saturn may be focused on the strangely empty space between the planet and its rings, but it's still taking time to do some local sightseeing. Cassini snapped this image of Saturn's largest moon Titan on May 7 from a distance of 303,000 miles (488,000 kilometers) away. The bright streaks are methane clouds, while the darker splotches seen toward the top are the moon's fascinating hydrocarbon lakes. NASA released two versions of the image on Tuesday with different levels of enhancement. One makes the bands and seas really pop out, while the other offers a softer, more ethereal view of the same scene. The Cassini mission, which launched in 1997, is scheduled to end in September when the spacecraft will destroy itself in Saturn's atmosphere. Cassini is a joint project from NASA, the European Space Agency and the Italian Space Agency. The probe is currently engaged in an ongoing series of dives that take it between Saturn and the rings as part of its mission "grand finale."

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