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  • richardmitnick 1:30 pm on August 18, 2016 Permalink | Reply
    Tags: , , , ESA's New Norcia station, Most Distant Catch for ESA Station, NASA Cassini   

    From ESA: “Most Distant Catch for ESA Station” 

    ESA Space For Europe Banner

    European Space Agency

    18 August 2016
    No writer credit found

    An ESA tracking station has acquired signals from the international Cassini spacecraft orbiting Saturn, across more than 1.4 billion km of space.

    Following a seven-year journey to Saturn, the NASA/ESA/ASI Cassini orbiter delivered Europe’s Huygens probe to the surface of Saturn’s mysterious moon Titan in January 2005, just a few months after becoming the first spacecraft to enter orbit around the giant gas planet.

    1
    Cassini crossing rings. In 2016, NASA’s Cassini mission will begin its final ‘Grand Finale’ and ESA’s superbly sensitive deep-space tracking stations will be called in to help gather crucial radio science data.ESA
    18/08/2016

    Since then, Cassini and Huygens have returned a wealth of information on the Saturnian system to the global scientific community, helping us understand the massive planet, its multiple moons and its hauntingly beautiful system of rings.

    Starting later this year, the mission will begin its final phase (see Cassini’s Grand Finale) and ESA’s superbly sensitive deep-space tracking stations will be called in to help gather crucial radio science data.

    2
    New Norcia station. ESA’s New Norcia station, DSA-1 (Deep Space Antenna-1), hosts a 35 m-diameter parabolic antenna and is located 140 km north of Perth, Western Australia, close to the town of New Norcia. DSA-1 communicates with deep-space missions, typically at ranges in excess of 2 million km. It is also capable of supporting the ultra-precise ‘delta-DOR’ navigation technique. ESA/S. Marti

    In an initial test on 10 August, ESA’s tracking station at New Norcia, Western Australia, hosting a 35 m-diameter, 630-tonne deep-space antenna, received signals transmitted by Cassini through 1.44 billion km of space.

    “This was the farthest-ever reception for an ESA station, and the radio signals – travelling at the speed of light – took 80 minutes to cover this vast distance,” says Daniel Firre, responsible for supporting Cassini radio science at ESOC, ESA’s operations centre in Darmstadt, Germany.

    “We had to upgrade some software at ESOC, as we discovered that one file used for pointing the antenna did not have enough digits to encode the full distance to Cassini, but the test worked and demonstrated we can catch Cassini’s transmissions.”

    Listening Across the Void

    Some types of radio science observations use a ground station to detect signals transmitted from a spacecraft that have reflected off a planet or moon’s surface, or passed through the various layers of its atmosphere – or, in the case of Saturn, its rings.

    Effects on the signals provide valuable information on the composition, state and structure of whatever they have passed through.

    3
    Tracking stations control room at ESOC

    Numerous missions, including ESA’s Venus Express and Mars Express, have used this technique in the past. All three of ESA’s deep-space tracking stations (New Norcia in Australia, Cebreros in Spain and Malargüe in Argentina) were specifically designed to enable a radio science capability.

    ESA/Venus Express
    ESA/Venus Express

    ESA/Mars Express Orbiter
    ESA/Mars Express Orbiter

    The Cassini mission has performed radio science observations many times during its time at Saturn. Previously, the mission relied solely on the antennas of NASA’s Deep Space Network for these observations.

    Now, the addition of ESA tracking capability will help provide the continuous radio contact needed during Cassini radio science activities. The data received by ESA will be delivered to NASA for subsequent scientific analysis.

    Radio Silence During the Grand Finale

    Starting in December and running into July 2017, Cassini will conduct a daring series of orbits in which the spacecraft will repeatedly climb high above Saturn’s poles, initially passing just outside its narrow F ring, and then later diving between the uppermost atmosphere and the innermost ring.

    4
    Grand Finale orbits. In 2016, NASA’s Cassini mission will begin its final ‘Grand Finale’ and ESA’s superbly sensitive deep-space tracking stations will be called in to help gather crucial radio science data. NASA/Jet Propulsion Lab

    When Cassini plunges past Saturn, an ESA station will listen, recording radio signals that will be relayed to NASA.

    These data will provide detailed maps of Saturn’s gravity, revealing the planet’s inner composition and possibly helping solve the mystery of just how fast the interior is rotating. They will also help scientists study the rings.

    Until December, a half-dozen more test passes using ESA’s New Norcia and Malargüe stations to receive Cassini signals are planned, after which the two will be used during some two-dozen Grand Finale orbits.

    Inter-Agency Coopration a Key Element

    The support is particularly challenging, as listening passes can last up to 30 hours, during which reception will be handed over multiple times between the two ESA stations and NASA’s Canberra deep-space communication complex in Australia; NASA’s Madrid complex will also take part.

    “We need uninterrupted signal reception to optimise the Cassini radio science data, so the ESA and NASA stations really have to work in close coordination for recording and handover,” says Manfred Lugert, responsible for ESA’s Estrack ground station network.

    Due to geometry, the two ESA stations – located in the southern hemisphere – are ideally able to support Cassini radio science. Northern/southern hemispheric coverage was one factor taken into account when ESA built its station in Argentina in 2012.

    “We are really pleased that we can work closely with our NASA colleagues and contribute to Cassini’s incredibly valuable radio science goals,” says Manfred, adding: “It’s an impressive display of what two agencies working together can achieve.”

    See the full article here .

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    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 6:03 am on July 7, 2016 Permalink | Reply
    Tags: , , , NASA Cassini,   

    From Science Alert: “Saturn’s biggest moon could support a new kind of alien life” 

    ScienceAlert

    Science Alert

    6 JUL 2016
    DAVID NIELD

    1
    Titan. NASA

    When it comes to looking for life on other planets, scientists tend to focus their search on planets that have the right conditions for liquid water to form, but Saturn’s moon Titan might just point the way to the existence of life without water.

    Researchers in the US have been analysing the chemical composition of Saturn’s largest satellite, and think the presence of hydrogen cyanide (HCN) molecules in the atmosphere could pave the way for different forms of life to evolve.

    That’s because HCN reacts to form polymers including polyimine, and polyimine is able to absorb a wide spectrum of light – so wide that it’s enough to capture light penetrating Titan’s dense and hazy atmosphere.

    With that light, the scientists think polyimine could be a possible catalyst for life.

    “Polyimine can exist as different structures, and they may be able to accomplish remarkable things at low temperatures, especially under Titan’s conditions,” said chemist Martin Rahm from Cornell University.

    “We are used to our own conditions here on Earth,” he adds. “Our scientific experience is at room temperature and ambient conditions. Titan is a completely different beast.”

    Titan is Earth-like in that its surface is covered with lakes, rivers, and seas, but these are made up of liquid methane and ethane rather than water. The nitrogen and methane in the air make the planet’s surface too toxic for humans to survive, but the researchers suggest other types of life could prosper.

    The study builds on the Cassini-Huygens missions that have been ongoing for nearly 20 years.

    NASA/ESA/ASI Cassini Spacecraft
    NASA/ESA/ASI Cassini Spacecraft

    ESA Huygens Probe on Cassini
    ESA Huygens Probe on Cassini

    The data collected by the Cassini orbiter and Huygens probe – which landed on Titan back in 2005 – have been invaluable in allowing the Cornell team to simulate a prebiotic chemical trail that could lead to life… but not quite life as we know it.

    The data from the NASA probes was plugged into a computer simulation run by Rahm and his team, which revealed that polyimine could spark life in the ultra-cold temperatures on the surface of Titan. Polyimine’s precursor, hydrogen cyanide, has previously been linked to the start of life on Earth.

    “If future observations could show there is prebiotic chemistry in a place like Titan, it would be a major breakthrough,” said Rahm. “This paper is indicating that prerequisites for processes leading to a different kind of life could exist on Titan, but this [is] only the first step.”

    The research could mean Titan offers two chances of hosting alien life. Scientists think that there is liquid water under the frozen surface of Titan, but locked away in a massive underground ocean – and there’s a lot of speculation that these kinds of underground oceans located throughout the Solar System could hypothetically give rise to life.

    In any case, if the researchers turn out to be right about the polyimine, we can broaden our search for extraterrestrial life beyond planets that very closely match Earth’s environments – and that could be pretty huge.

    Watch this space.

    The findings have been published in Proceedings of the National Academy of Sciences.

    See the full article here .

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  • richardmitnick 2:40 pm on April 14, 2016 Permalink | Reply
    Tags: , , NASA Cassini, , Space dust at Saturn   

    From JPL: “Saturn Spacecraft Samples Interstellar Dust” 

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    JPL-Caltech

    Preston Dyches
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-7013
    preston.dyches@jpl.nasa.gov

    Markus Bauer
    European Space Agency, Noordwijk, Netherlands
    011-31-71-565-6799
    markus.bauer@esa.int

    Written by Emily Baldwin, ESA

    1
    Of the millions of dust grains Cassini has sampled at Saturn, a few dozen appear to have come from beyond our solar system. Scientists believe these special grains have interstellar origins because they moved much faster and in different directions compared to dusty material native to Saturn. Image credit: NASA/JPL-Caltech

    NASA/ESA/ASI Cassini Spacecraft
    NASA/ESA/ASI Cassini Spacecraft

    NASA’s Cassini spacecraft has detected the faint but distinct signature of dust coming from beyond our solar system. The research, led by a team of Cassini scientists primarily from Europe, is published this week in the journal Science*.

    Cassini has been in orbit around Saturn since 2004, studying the giant planet, its rings and its moons. The spacecraft has also sampled millions of ice-rich dust grains with its cosmic dust analyzer instrument. The vast majority of the sampled grains originate from active jets that spray from the surface of Saturn’s geologically active moon Enceladus.

    But among the myriad microscopic grains collected by Cassini, a special few — just 36 grains — stand out from the crowd. Scientists conclude these specks of material came from interstellar space — the space between the stars.

    Alien dust in the solar system is not unanticipated. In the 1990s, the ESA/NASA Ulysses mission made the first in-situ observations of this material, which were later confirmed by NASA’s Galileo spacecraft. The dust was traced back to the local interstellar cloud: a nearly empty bubble of gas and dust that our solar system is traveling through with a distinct direction and speed.

    NASA/ESA Ulysses
    NASA/ESA Ulysses

    NASA/Galileo
    NASA/Galileo

    “From that discovery, we always hoped we would be able to detect these interstellar interlopers at Saturn with Cassini. We knew that if we looked in the right direction, we should find them,” said Nicolas Altobelli, Cassini project scientist at ESA (European Space Agency) and lead author of the study. “Indeed, on average, we have captured a few of these dust grains per year, travelling at high speed and on a specific path quite different from that of the usual icy grains we collect around Saturn.”

    The tiny dust grains were speeding through the Saturn system at over 45,000 mph (72,000 kilometers per hour), fast enough to avoid being trapped inside the solar system by the gravity of the sun and its planets.

    “We’re thrilled Cassini could make this detection, given that our instrument was designed primarily to measure dust from within the Saturn system, as well as all the other demands on the spacecraft,” said Marcia Burton, a Cassini fields and particles scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, and a co-author of the paper.

    Importantly, unlike Ulysses and Galileo, Cassini was able to analyze the composition of the dust for the first time, showing it to be made of a very specific mixture of minerals, not ice. The grains all had a surprisingly similar chemical make-up, containing major rock-forming elements like magnesium, silicon, iron and calcium in average cosmic proportions. Conversely, more reactive elements like sulfur and carbon were found to be less abundant compared to their average cosmic abundance.

    “Cosmic dust is produced when stars die, but with the vast range of types of stars in the universe, we naturally expected to encounter a huge range of dust types over the long period of our study,” said Frank Postberg of the University of Heidelberg, a co-author of the paper and co-investigator of Cassini’s dust analyzer.

    Stardust grains are found in some types of meteorites, which have preserved them since the birth of our solar system. They are generally old, pristine and diverse in their composition. But surprisingly, the grains detected by Cassini aren’t like that. They have apparently been made rather uniform through some repetitive processing in the interstellar medium, the researchers said.

    The authors speculate on how this processing of dust might take place: Dust in a star-forming region could be destroyed and recondense multiple times as shock waves from dying stars passed through, resulting in grains like the ones Cassini observed streaming into our solar system.

    “The long duration of the Cassini mission has enabled us to use it like a micrometeorite observatory, providing us privileged access to the contribution of dust from outside our solar system that could not have been obtained in any other way,” said Altobelli.

    The Cassini-Huygens mission is a cooperative project of NASA, ESA and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate in Washington. The Cosmic Dust Analyzer is supported by the German Aerospace Center (DLR); the instrument is managed by the University of Stuttgart, Germany.

    For more information about Cassini, visit:

    http://www.nasa.gov/cassini

    http://saturn.jpl.nasa.gov

    *Science paper:
    Flux and composition of interstellar dust at Saturn from Cassini’s Cosmic Dust Analyzer

    Science team:
    N. Altobelli, 1,*,†; F. Postberg, 2,3,†; K. Fiege, 2,4,†;, M. Trieloff, 2,5,†; H. Kimura, 6; V. J. Sterken, 7; H.-W. Hsu, 8; J. Hillier,9; N. Khawaja,3; G. Moragas-Klostermeyer,3; J. Blum, 10;
    M. Burton, 11; R. Srama, 3; S. Kempf, 8; E. Gruen, 2,3,8

    • Author Affiliations

    1 European Space Agency, European Space Astronomy Centre, Madrid, Spain.
    2 Institut für Geowissenschaften, University of Heidelberg, Heidelberg, Germany.
    3 Institut für Raumfahrtsysteme, University of Stuttgart, Stuttgart, Germany.
    4 Georgia Institute of Technology, School of Chemistry and Biochemistry, Atlanta, GA, USA.
    5 Klaus-Tschira-Labor für Kosmochemie, University of Heidelberg, Heidelberg, Germany.
    6 Kobe University, Kobe, Hyōgo, Japan.
    7 International Space Sciences Institute, Bern, Switzerland.
    8 University of Boulder, Boulder, CO, USA.
    9 University of Kent, Kent, UK.
    10 Technische Universität Braunschweig, Institut für Geophysik und Extraterrestrische Physik, Braunschweig, Germany.
    11 Jet Propulsion Laboratory, Pasadena, CA, USA.

    ↵*Corresponding author. E-mail: nicolas.altobelli@sciops.esa.int

    ↵† These authors contributed equally to this work.

    See the full article here .

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 10:04 am on August 14, 2015 Permalink | Reply
    Tags: , , NASA Cassini   

    From JPL: “Cassini to Make Last Close Flyby of Saturn Moon Dione” 

    JPL

    August 13, 2015
    Media Contact
    Preston Dyches
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-7013
    preston.dyches@jpl.nasa.gov

    1

    NASA’s Cassini spacecraft will zip past Saturn’s moon Dione on Monday, Aug. 17 — the final close flyby of this icy satellite during the spacecraft’s long mission.

    NASA Cassini Spacecraft
    Cassini

    Cassini’s closest approach, within 295 miles (474 kilometers) of Dione’s surface, will occur at 11:33 a.m. PDT (2:33 p.m. EDT). Mission controllers expect fresh images to begin arriving on Earth within a couple of days following the encounter.

    Cassini scientists have a bevy of investigations planned for Dione. Gravity-science data from the flyby will improve scientists’ knowledge of the moon’s internal structure and allow comparisons to Saturn’s other moons. Cassini has performed this sort of gravity science investigation with only a handful of Saturn’s 62 known moons.

    During the flyby, Cassini’s cameras and spectrometers will get a high-resolution peek at Dione’s north pole at a resolution of only a few feet (or meters). In addition, Cassini’s Composite Infrared Spectrometer instrument will map areas on the icy moon that have unusual thermal anomalies — those regions are especially good at trapping heat. Meanwhile, the mission’s Cosmic Dust Analyzer continues its search for dust particles emitted from Dione.

    This flyby will be the fifth targeted encounter with Dione of Cassini’s tour at Saturn. Targeted encounters require maneuvers to precisely steer the spacecraft toward a desired path above a moon. The spacecraft executed a 12-second burn using its thrusters on Aug. 9, which fine-tuned the trajectory to enable the upcoming encounter.

    Cassini’s closest-ever flyby of Dione was in Dec. 2011, at a distance of 60 miles (100 kilometers). Those previous close Cassini flybys yielded high-resolution views of the bright, wispy terrain on Dione first seen during the Voyager mission. Cassini’s sharp views revealed the bright features to be a system of braided canyons with bright walls. Scientists also have been eager to find out if Dione has geologic activity, like Saturn’s geyser-spouting moon Enceladus, but at a much lower level.

    “Dione has been an enigma, giving hints of active geologic processes, including a transient atmosphere and evidence of ice volcanoes. But we’ve never found the smoking gun. The fifth flyby of Dione will be our last chance,” said Bonnie Buratti, a Cassini science team member at NASA’s Jet Propulsion Laboratory in Pasadena, California.

    Cassini has been orbiting Saturn since 2004. After a series of close moon flybys in late 2015, the spacecraft will depart Saturn’s equatorial plane — where moon flybys occur most frequently — to begin a year-long setup of the mission’s daring final year. For its grand finale, Cassini will repeatedly dive through the space between Saturn and its rings.

    “This will be our last chance to see Dione up close for many years to come,” said Scott Edgington, Cassini mission deputy project scientist at JPL. “Cassini has provided insights into this icy moon’s mysteries, along with a rich data set and a host of new questions for scientists to ponder.”

    The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. JPL, a division of the California Institute of Technology, manages the mission for NASA’s Science Mission Directorate in Washington.

    For more information about Cassini, visit:

    http://www.nasa.gov/cassini

    http://saturn.jpl.nasa.gov

    See the full article here.

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 2:46 pm on March 11, 2015 Permalink | Reply
    Tags: , , NASA Cassini,   

    From JPL: “Spacecraft Data Suggest Saturn Moon’s Ocean May Harbor Hydrothermal Activity” 

    JPL

    March 11, 2015
    Preston Dyches
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-7013
    preston.dyches@jpl.nasa.gov

    Dwayne Brown
    NASA Headquarters, Washington
    202-358-1726
    dwayne.c.brown@nasa.gov

    1
    This cutaway view of Saturn’s moon Enceladus is an artist’s rendering that depicts possible hydrothermal activity that may be taking place on and under the seafloor of the moon’s subsurface ocean, based on recently published results from NASA’s Cassini mission. Hydrothermal activity is a process where seawater infiltrates and reacts with a rocky crust, emerging as a heated, mineral-laden solution. This is a natural occurrence in Earth’s oceans. Researchers think microscopic grains of rock detected in the Saturn system by Cassini most likely form when hot water containing dissolved minerals from the moon’s rocky interior travels upward, coming into contact with cooler water. Temperatures required for the interactions that produce the tiny rock grains would be at least 194 degrees Fahrenheit (90 degrees Celsius). On Earth, the most common way to form silica grains of the 6-to-9-nanometer size found by Cassini is hydrothermal activity involving a specific range of conditions. Namely, when slightly alkaline, slightly salty water that is super-saturated with silica undergoes a big drop in temperature. Gravity science measurements from Cassini also suggest Enceladus’ rocky core is quite porous, which would allow water from the ocean to percolate into the interior. This would provide a huge surface area where rock and water could interact. Cassini first revealed active geology on Enceladus in 2005 with evidence of an icy spray issuing from the moon’s south polar region and higher-than-expected temperatures in the icy surface there. With its powerful suite of complementary science instruments, the mission soon revealed a towering plume of water ice and vapor, salts and organic materials that issues from relatively warm fractures on the wrinkled surface. Gravity science results published in 2014 strongly suggested the presence of a 6-mile- (10-kilometer-) deep ocean beneath an ice shell about 19 to 25 miles (30 to 40 kilometers) thick.

    Fast Facts:

    › Cassini finds first evidence of active hot-water chemistry beyond planet Earth
    › Findings in two separate papers support the notion
    › The results have important implications for the habitability of icy worlds

    NASA’s Cassini spacecraft has provided scientists the first clear evidence that Saturn’s moon Enceladus exhibits signs of present-day hydrothermal activity which may resemble that seen in the deep oceans on Earth. The implications of such activity on a world other than our planet open up unprecedented scientific possibilities.

    NASA Cassini Spacecraft
    Cassini

    “These findings add to the possibility that Enceladus, which contains a subsurface ocean and displays remarkable geologic activity, could contain environments suitable for living organisms,” said John Grunsfeld, astronaut and associate administrator of NASA’s Science Mission Directorate in Washington. “The locations in our solar system where extreme environments occur in which life might exist may bring us closer to answering the question: are we alone in the universe.”

    Hydrothermal activity occurs when seawater infiltrates and reacts with a rocky crust and emerges as a heated, mineral-laden solution, a natural occurrence in Earth’s oceans. According to two science papers, the results are the first clear indications an icy moon may have similar ongoing active processes.

    The first paper, published this week in the journal Nature, relates to microscopic grains of rock detected by Cassini in the Saturn system. An extensive, four-year analysis of data from the spacecraft, computer simulations and laboratory experiments led researchers to the conclusion the tiny grains most likely form when hot water containing dissolved minerals from the moon’s rocky interior travels upward, coming into contact with cooler water. Temperatures required for the interactions that produce the tiny rock grains would be at least 194 degrees Fahrenheit (90 degrees Celsius).

    “It’s very exciting that we can use these tiny grains of rock, spewed into space by geysers, to tell us about conditions on — and beneath — the ocean floor of an icy moon,” said the paper’s lead author Sean Hsu, a postdoctoral researcher at the University of Colorado at Boulder.

    Cassini’s cosmic dust analyzer (CDA) instrument repeatedly detected miniscule rock particles rich in silicon, even before Cassini entered Saturn’s orbit in 2004. By process of elimination, the CDA team concluded these particles must be grains of silica, which is found in sand and the mineral quartz on Earth. The consistent size of the grains observed by Cassini, the largest of which were 6 to 9 nanometers, was the clue that told the researchers a specific process likely was responsible.

    On Earth, the most common way to form silica grains of this size is hydrothermal activity under a specific range of conditions; namely, when slightly alkaline and salty water that is super-saturated with silica undergoes a big drop in temperature.

    “We methodically searched for alternate explanations for the nanosilica grains, but every new result pointed to a single, most likely origin,” said co-author Frank Postberg, a Cassini CDA team scientist at Heidelberg University in Germany.

    Hsu and Postberg worked closely with colleagues at the University of Tokyo who performed the detailed laboratory experiments that validated the hydrothermal activity hypothesis. The Japanese team, led by Yasuhito Sekine, verified the conditions under which silica grains form at the same size Cassini detected. The researchers think these conditions may exist on the seafloor of Enceladus, where hot water from the interior meets the relatively cold water at the ocean bottom.

    The extremely small size of the silica particles also suggests they travel upward relatively quickly from their hydrothermal origin to the near-surface sources of the moon’s geysers. From seafloor to outer space, a distance of about 30 miles (50 kilometers), the grains spend a few months to a few years in transit, otherwise they would grow much larger.

    The authors point out that Cassini’s gravity measurements suggest Enceladus’ rocky core is quite porous, which would allow water from the ocean to percolate into the interior. This would provide a huge surface area where rock and water could interact.

    The second paper, recently published in Geophysical Research Letters, suggests hydrothermal activity as one of two likely sources of methane in the plume of gas and ice particles that erupts from the south polar region of Enceladus. The finding is the result of extensive modeling to address why methane, as previously sampled by Cassini, is curiously abundant in the plume.

    The team found that, at the high pressures expected in the moon’s ocean, icy materials called clathrates could form that imprison methane molecules within a crystal structure of water ice. Their models indicate that this process is so efficient at depleting the ocean of methane that the researchers still needed an explanation for its abundance in the plume.

    In one scenario, hydrothermal processes super-saturate the ocean with methane. This could occur if methane is produced faster than it is converted into clathrates. A second possibility is that methane clathrates from the ocean are dragged along into the erupting plumes and release their methane as they rise, like bubbles forming in a popped bottle of champagne.

    The authors agree both scenarios are likely occurring to some degree, but they note that the presence of nanosilica grains, as documented by the other paper, favors the hydrothermal scenario.

    “We didn’t expect that our study of clathrates in the Enceladus ocean would lead us to the idea that methane is actively being produced by hydrothermal processes,” said lead author Alexis Bouquet, a graduate student at the University of Texas at San Antonio. Bouquet worked with co-author Hunter Waite, who leads the Cassini Ion and Neutral Mass Spectrometer (INMS) team at Southwest Research Institute in San Antonio.

    Cassini first revealed active geological processes on Enceladus in 2005 with evidence of an icy spray issuing from the moon’s south polar region and higher-than-expected temperatures in the icy surface there. With its powerful suite of complementary science instruments, the mission soon revealed a towering plume of water ice and vapor, salts and organic materials that issues from relatively warm fractures on the wrinkled surface. Gravity science results published in 2014 strongly suggested the presence of a 6-mile- (10-kilometer-) deep ocean beneath an ice shell about 19 to 25 miles (30 to 40 kilometers) thick.

    The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. NASA’s Jet Propulsion Laboratory in Pasadena, California, manages the mission for the agency’s Science Mission Directorate in Washington. The Cassini CDA instrument was provided by the German Aerospace Center. The instrument team, led by Ralf Srama, is based at the University of Stuttgart in Germany. JPL is a division of the California Institute of Technology in Pasadena.

    More information about Cassini, visit:

    http://www.nasa.gov/cassini

    and

    http://saturn.jpl.nasa.gov

    See the full article here.

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 8:09 am on January 9, 2015 Permalink | Reply
    Tags: , , NASA Cassini, NRAO VBLA,   

    From BBC: “Saturn pinpointed to within one mile by giant telescope” 

    BBC
    BBC

    9 January 2015
    Jonathan Webb

    Thanks to a continent-wide radio telescope, astronomers say they know where Saturn is – to within one mile. The calculation is many times more accurate than previous estimations and will be useful for the future study of our solar system and beyond. It used signals sent by the spacecraft Cassini, orbiting Saturn since 2004.

    NASA Cassini Spacecraft
    Cassini

    Ten antennae scattered from Hawaii to the Virgin Islands performed the precise measurement, despite Saturn being nearly a billion miles away.
    This powerful assembly is known as the Very Long Baseline Array (VLBA), a giant telescope in ten parts. The findings were reported at a meeting of the American Astronomical Society in Seattle.

    NRAO VLBA

    “Because of [the VLBA’s] large geographic extent, it has the ability to make very high resolution images – but for this study, the critical thing it can do is measure very precise angles,” explained Dr Dayton Jones of Nasa’s Jet Propulsion Laboratory.

    Dr Jones and his colleagues tracked Cassini’s position relative to a reference grid of quasars – bright, ancient radio wave sources well beyond our galaxy.

    s
    Saturn, pictured by Cassini and now pinpointed in space thanks to the craft’s transmissions

    Without using this type of radio astronomy, where the antennae compare notes in a technique known as “interferometry“, Dr Jones said the best estimates of Saturn’s location were about 20 times less precise.

    From our distant vantage point, predicting Saturn’s trajectory to within about one mile is the equivalent of “the width of a dime at 2,000 miles”, Dr Jones said.

    “This is very good, and far better than previous techniques have been able to provide,” he added, commending the “extraordinary precision” of the VLBA.

    And that precision is especially important when it concerns a giant planet like Saturn.

    “Getting better orbits… particularly for the two planets that dominate the dynamics of our solar system, Jupiter and Saturn, improves the basis of the entire ephemeris,” Dr Jones said.

    Exact model

    An ephemeris is a table of predicted locations in space.

    It has widespread uses in astronomy. Scientists who study the blinking light of pulsars have to be sure of their timing, and require an incredibly exact model of Earth’s own orbit.

    “And all the other bodies in the solar system affect the Earth’s orbit, so you really want to have that all put together in a nice consistent system,” Dr Jones told the BBC.

    Furthermore, when it comes to planning an actual mission there is little room for error.

    “If you want to send a spacecraft to orbit one of the moons of Saturn or Jupiter, you really do want to know what that trajectory has to be, to get there at the same time as the planets do!”

    See the full article here.

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  • richardmitnick 3:16 pm on December 17, 2014 Permalink | Reply
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    From AAAS: “Spacecraft spots probable waves on Titan’s seas” 

    AAAS

    AAAS

    16 December 2014
    Eric Hand

    It’s springtime on Titan, Saturn’s giant and frigid moon, and the action on its hydrocarbon seas seems to be heating up. Near the moon’s north pole, there is growing evidence for waves on three different seas, scientists reported here today at a meeting of the American Geophysical Union. Researchers are also coming up with the first estimates for the volume and composition of the seas. The bodies appear to be made mostly of methane, and not mostly ethane as previously thought. And they are deep: Ligeia Mare, the second biggest sea with an area larger than Lake Superior, could contain 55 times Earth’s oil reserves.

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    Ligeia Mare, shown here in a false-color image from NASA’s Cassini mission, is the second largest known body of liquid on Saturn’s moon Titan. It is filled with liquid hydrocarbons, such as ethane and methane, and is one of the many seas and lakes that bejewel Titan’s north polar region. Cassini has yet to observe waves on Ligeia Mare and will look again during its next encounter on May 23, 2013. The image is a false-color mosaic of synthetic aperture radar images obtained by the Cassini spacecraft between February 2006 and April 2007. Dark areas (low radar return) are colored black while bright regions (high radar return) are colored yellow to white. In this color scheme, liquids, which are dark to the radar, end up appearing black and the solid surface of Titan, which appears bright to the radar, ends up appearing yellow.

    NASA Cassini Spacecraft
    NASA/Cassini

    The evidence is coming from NASA’s Cassini spacecraft, which has being exploring the Saturn system since 2004. In 2009, the northern hemisphere of Titan passed its spring equinox, when it begins tilting toward the sun, and climate models predicted that the increased light would kick up winds as the moon approaches summer in 2017.

    That appears to be happening. In a handful of flybys of Titan in the past 6 months, Cassini scientists have seen signs of waves on three different seas: Kraken Mare, Ligeia Mare, and Punga Mare. Some of the evidence is based on radar reflections, which detect roughness at the sea surface. Particularly intriguing has been a feature on Ligeia Mare dubbed the Magic Island because it appeared, disappeared, and reappeared over the past 2 years. Jason Hofgartner, a planetary science graduate student at Cornell University, says that a likely explanation is transient episodes of waves. “It is neither magical nor an island. But the name has stuck,” he says.

    k
    This is a segment of a colorized mosaic from NASA’s Cassini mission that shows the most complete view yet of Titan’s northern land of lakes and seas. Saturn’s moon Titan is the only world in our solar system other than Earth that has stable liquid on its surface. The liquid in Titan’s lakes and seas is mostly methane and ethane. Seas and major lakes are labeled in the annotated version. The data were obtained by Cassini’s radar instrument from 2004 to 2013. In this color scheme, liquids appear blue and black depending on the way the radar bounced off the surface. Land areas appear yellow to white. Kraken Mare, Titan’s largest sea, is the body in black and blue that sprawls from just below and to the right of the north pole down to the bottom. Most of the bodies of liquid on Titan occur in the northern hemisphere. In fact nearly all the lakes and seas on Titan fall into a box covering about 600 by 1,100 miles (900 by 1,800 kilometers). Only 3 percent of the liquid at Titan falls outside of this area. Scientists are trying to identify the geologic processes that are creating large depressions capable of holding major seas in this limited area. A prime suspect is regional extension of the crust, which on Earth leads to the formation of faults creating alternating basins and roughly parallel mountain ranges. This process has shaped the Basin and Range province of the western United States, and during the period of cooler climate 13,000 years ago much of the present state of Nevada was flooded with Lake Lahontan, which (though smaller) bears a strong resemblance to the region of closely packed seas on Titan.

    p
    This is a segment of a colorized mosaic from NASA’s Cassini mission that shows the most complete view yet of Titan’s northern land of lakes and seas. Saturn’s moon Titan is the only world in our solar system other than Earth that has stable liquid on its surface. The liquid in Titan’s lakes and seas is mostly methane and ethane. The data were obtained by Cassini’s radar instrument from 2004 to 2013. In this color scheme, liquids appear blue and black depending on the way the radar bounced off the surface. Land areas appear yellow to white. Punga Mare is just below the north pole.
    Most of the bodies of liquid on Titan occur in the northern hemisphere. In fact nearly all the lakes and seas on Titan fall into a box covering about 600 by 1,100 miles (900 by 1,800 kilometers). Only 3 percent of the liquid at Titan falls outside of this area.

    Scientists involved in the discoveries have been cautious, saying that the features could also be floating debris or bubbles. At Kraken Mare, however, Cassini researchers detected a wavelike feature with both the spacecraft’s radar and a mapping spectrometer. That double detection gives Alexander Hayes, a planetary scientist at Cornell, extra confidence. “It’s most likely waves,” Hayes says. He calculates that the waves are moving at about 0.7 meters per second and at heights of about 1.5 centimeters. “They’re not huge,” he says. Right now, Hayes says, the waves seem to be appearing only in scattered patches where islands or canyons could be funneling winds—a phenomenon that sailors call cat’s paws. In January, Cassini will make another flyby of Titan that will allow the spectrometer a chance to confirm a radar feature detected in Punga Mare.

    NASA
    Chief Scientist Ellen Stofan, who has spent much of her career studying Titan, calls the results a “vindication” for those who predicted seasonal change. “To me, it’s exciting,” she says. “It says that Titan is a dynamic place.” She says that Cassini scientists can now look for evidence that the waves, now or in the past, have eroded into the jagged, frozen shorelines and created long, straight beaches—features that have been mostly lacking in Cassini data.

    Other scientists at the meeting reported on using Cassini’s radar to assess the size and contents of the seas. The maximum depth of Kraken Mare appears to be 160 meters, and Ligeia Mare could be as much as 200 meters deep, reported Marco Mastrogiuseppe of Sapienza University of Rome. The fact that the radar signals could bounce off the sea bottom suggests that the seas were more transparent than expected and thus must contain mostly methane, not ethane. Hayes says his best estimate is about 90% methane. Essam Marouf, a planetary scientist at San José State University in California, reported on the first results from a separate radar experiment that sent radar reflections to Earth instead of back to the spacecraft. Those tests provide independent evidence that the seas are dominated by methane, Marouf says, and it implies that the lakes are kept filled by precipitating methane.

    Decades ago, planetary scientists such as David Stevenson of the California Institute of Technology in Pasadena had predicted that the seas might be mostly ethane. “It certainly wasn’t obvious that they would be methane-dominated,” Stevenson says. Part of the reason for that presupposition is that light coverts methane in the atmosphere to ethane. Over billions of years, this process would deplete Titan’s surface stores of methane unless it was kept resupplied by a reservoir. Some scientists have proposed that erupting cryovolcanoes or deep underground aquifers of liquid methane occasionally recharge Titan with methane. “There is an unsolved question underlying this,” Stevenson says. “Where does all the methane come from?”

    *Correction, 17 December, 11 a.m.: This item originally used the phrase “bodies of water” to describe methane seas. We have struck the words “of water.”

    See the full article here.

    The American Association for the Advancement of Science is an international non-profit organization dedicated to advancing science for the benefit of all people.

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  • richardmitnick 2:02 pm on December 10, 2014 Permalink | Reply
    Tags: , , , , NASA Cassini,   

    From JPL- “Saturn’s Moons: What a Difference a Decade Makes “ 

    JPL

    December 9, 2014
    Preston Dyches
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-7013
    preston.dyches@jpl.nasa.gov

    Almost immediately after NASA’s twin Voyager spacecraft made their brief visits to Saturn in the early 1980s, scientists were hungry for more. The Voyagers had offered them only a brief glimpse of a family of new worlds — Saturn’s icy moons — and the researchers were eager to spend more time among those bodies.

    NASA Voyager 1
    NASA/Voyager 1

    NASA Voyager 2
    NASA/Voyager 2

    The successor to the Voyagers at Saturn, NASA’s Cassini spacecraft, has spent the past 10 years collecting images and other data as it has toured the Ringed Planet and its family of satellites. New color maps, produced from this trove of data, show that Cassini has essentially fulfilled one of its many mission objectives: producing global maps of Saturn’s six major icy moons.

    NASA Cassini Spacecraft
    NASA/Cassini

    These are the large Saturnian moons, excluding haze-covered Titan, known before the start of the Space Age: Mimas, Enceladus, Tethys, Dione, Rhea and Iapetus. Aside from a gap in the north polar region of Enceladus (to be filled in next year), and some areas of Iapetus, this objective is now more or less complete.

    Before (Voyager)
    m

    After (Cassini)
    a
    Mimas

    Before (Voyager)
    e
    After (Cassini)
    a
    Enceladus.

    Before (Voyager)
    t
    After (Cassini)
    k
    Tethys

    Before (Voyager)
    d
    After (Cassini)
    s
    Dione

    Before (Voyager)
    r
    After (Cassini)
    r
    Rhea

    Before (Voyager)
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    After (Cassini)
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    Iapetus

    All maps Image Credit: NASA/JPL-Caltech/SSI/LPI

    The new maps are the best global, color maps of these moons to date, and the first to show natural brightness variations and high-resolution color together. Colors in the maps represent a broader range than human vision, extending slightly into infrared and ultraviolet wavelengths. Differences in color across the moons’ surfaces that are subtle in natural-color views become much easier to study in these enhanced colors.

    Cassini’s enhanced color views have yielded several important discoveries about the icy moons. The most obvious are differences in color and brightness between the two hemispheres of Tethys, Dione and Rhea. The dark reddish colors on the moons’ trailing hemispheres are due to alteration by charged particles and radiation in Saturn’s magnetosphere. Except for Mimas and Iapetus, the blander leading hemispheres of these moons — that is, the sides that always face forward as the moons orbit Saturn — are all coated with icy dust from Saturn’s E-ring, formed from tiny particles erupting from the south pole of Enceladus.

    Enceladus itself displays a variety of colorful features. Some of the gas and dust being vented into space from large fractures near the moon’s south pole returns to the surface and paints Enceladus with a fresh coating. The yellow and magenta tones in Cassini’s color map are thought to be due to differences in the thickness of these deposits. Many of the most recently formed fractures on Enceladus, those near the south pole in particular, have a stronger ultraviolet signature, which appears bluish in these maps. Their color may be due to large-grained ice exposed on the surface, not unlike blue ice seen in some places in Earth’s Arctic.

    The new maps were produced by Paul Schenk, a participating scientist with the Cassini imaging team based at the Lunar and Planetary Institute in Houston.

    The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory in Pasadena, California, manages the Cassini and Voyager missions for NASA’s Science Mission Directorate in Washington. The two Voyager spacecraft and the Cassini orbiter, along with its two onboard cameras, were designed, developed and assembled at JPL. The Cassini imaging team consists of scientists from the United States, England, France and Germany. The imaging team is based at the Space Science Institute in Boulder, Colorado.

    More information about Cassini is available at the following sites:

    http://www.nasa.gov/cassini

    http://saturn.jpl.nasa.gov

    See the full article here.

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 6:18 am on December 8, 2014 Permalink | Reply
    Tags: , , , , , NASA Cassini   

    From ESA: “Cassini’s view of Jupiter’s southern hemisphere” 

    ESASpaceForEuropeBanner
    European Space Agency

    08/12/2014

    This Cassini image shows Jupiter from an unusual perspective. If you were to float just beneath the giant planet and look directly up, you would be greeted with this striking sight: red, bronze and white bands encircling a hazy south pole. The multicoloured concentric layers are broken in places by prominent weather systems such as Jupiter’s famous Great Red Spot, visible towards the upper left, chaotic patches of cloud and pale white dots. Many of these lighter patches contain lightning-filled thunderstorms.

    j

    NASA Cassini Spacecraft
    NASA/Cassini

    Jupiter has very dramatic weather – the planet’s axis is not as tilted (towards or away from the Sun) as much as Earth’s so it does not have significant seasonal changes, but it does have a thick and tumultuous atmosphere filled with raging storms and chaotic cloud systems.

    These clouds, formed from dense layers of ammonia crystals, are tugged, stretched and tangled together by Jupiter’s turbulence and strong winds, creating vortices and hurricane-like storms with wind speeds of up to 360 km per hour.

    The Great Red Spot is actually an anticyclone that has been violently churning for hundreds of years. It was at one stage large enough to contain several Earth-sized planets but recent images from the Hubble Space Telescope show it to be shrinking. There are other similarly striking storms raging in both Jupiter’s cool upper atmosphere and hotter lower layers, including a Great Dark Spot and Oval BA, more affectionately nicknamed Red Spot Jr.

    Jupiter’s south pole is at the very centre of this image, visible as a murky grey-toned circle. This patch is not as detailed as the rest of the planet because Cassini had to peer through a lot more atmospheric haze in the polar region, making it harder to see.

    This polar map is composed of 18 colour images taken by the narrow-angle camera on NASA’s Cassini spacecraft during a flyby on 11–12 December 2000. This map is incredibly detailed; the smallest visible features in this image are about 120 km across. There is also an accompanying map of the planet’s north pole. In 2016, NASA’s Juno spacecraft will arrive at Jupiter and start to beam back images of the planet’s poles.

    The Cassini–Huygens mission, launched in 1997 as a joint endeavour of ESA, NASA and Italy’s ASI space agency, flew past Venus, Earth and Jupiter en route to observe Saturn, its moons and rings. Observations with Cassini have given us an unprecedented understanding of the Saturnian system. ESA’s Juice mission aims to do the same for Jupiter. Planned for launch in 2022, the spacecraft will reach Jupiter in 2030 and begin observing the planet and three of its moons – Ganymede, Callisto and Europa. Previous flybys of these moons have raised the exciting prospect that some of them might harbour subsurface liquid oceans and conditions suitable to support some forms of life.

    Juice was recently given the green light to continue to the next stage of development.

    ESA JUICE

    See the full article here.

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    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 9:48 am on November 11, 2014 Permalink | Reply
    Tags: , , , , NASA Cassini   

    From NASA/Cassini: “Cassini Sails into New Ocean Adventures on Titan” 

    NASA Cassini Spacecraft

    Cassini-Huygens

    November 10, 2014
    Preston Dyches
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-7013
    preston.dyches@jpl.nasa.gov

    NASA’s Cassini mission continues its adventures in extraterrestrial oceanography with new findings about the hydrocarbon seas on Saturn’s moon Titan. During a flyby in August, the spacecraft sounded the depths near the mouth of a flooded river valley and observed new, bright features in the seas that might be related to the mysterious feature that researchers dubbed the “magic island.”

    The findings are being presented this week at the Division for Planetary Sciences Meeting of the American Astronomical Society held in Tucson, Arizona.

    To the delight of Cassini scientists, two new bright features appeared in Titan’s largest sea, Kraken Mare, during the August 21 flyby. In contrast to a previously reported bright, mystery feature in another of Titan’s large seas, Ligeia Mare, the new features in Kraken Mare were observed in both radar data and images from Cassini’s Visible and Infrared Mapping Spectrometer (VIMS). Having observations at two different wavelengths provides researchers with important clues to the nature of these enigmatic objects.

    km
    False-color mosaic of synthetic aperture radar images showing all of Kraken Mare. The large island Mayda Insula is left of top center, and Jingpo Lacus is at upper left. A portion of Ligeia Mare enters the view at top right.

    lm
    Ligeia Mare from a false-color mosaic of synthetic aperture radar images of Titan’s north polar region.

    The VIMS data suggest the new features might have similarities to places in and around the seas that the Cassini team has interpreted as waves or wet ground. The observations support two of the possible explanations the team thinks are most likely — that the features might be waves or floating debris.

    Unfortunately for mystery lovers, the August Titan flyby marked the final opportunity for Cassini’s radar to observe Kraken Mare. However, the spacecraft is scheduled to observe the original “magic island” feature in Ligeia Mare once more, in January 2015.

    The August Titan flyby also included a segment designed to collect altimetry (or height) data, using the spacecraft’s radar instrument along a 120-mile (200-kilometer) shore-to-shore track of Kraken Mare. For a 25-mile (40-kilometer) segment of this data along the sea’s eastern shoreline, Cassini’s radar beam bounced off the sea bottom and back to the spacecraft, revealing the sea’s depth in that area. This region, which is near the mouth of a large, flooded river valley, showed depths of 66 to 115 feet (20 to 35 meters). Cassini will perform this experiment one last time in January 2015, to try to measure the depth of Punga Mare. Punga Mare is the smallest of three large seas in Titan’s far north, and the only sea whose depth has not been observed by Cassini.

    pm
    Punga Mare from a false-color mosaic of synthetic aperture radar images of Titan’s north polar region. A northern extension of Kraken Mare enters the view at lower right.

    Scientists think that, for the areas in which Cassini did not observe a radar echo from the seafloor, Kraken Mare might be too deep for the radar beam to penetrate. Alternatively, the signal over this region might simply have been absorbed by the liquid, which is mostly methane and ethane. The altimetry data for the area in and around Kraken Mare also showed relatively steep slopes leading down to the sea, which also suggests the Kraken Mare might indeed be quite deep.

    The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology, Pasadena, manages the mission for NASA’s Science Mission Directorate in Washington. The VIMS team is based at the University of Arizona in Tucson. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the US and several European countries.

    More information about Cassini is available at the following sites:

    http://www.nasa.gov/cassini

    http://saturn.jpl.nasa.gov

    See the full article here.

    Cassini completed its initial four-year mission to explore the Saturn System in June 2008 and the first extended mission, called the Cassini Equinox Mission, in September 2010. Now, the healthy spacecraft is seeking to make exciting new discoveries in a second extended mission called the Cassini Solstice Mission.

    The mission’s extension, which goes through September 2017, is named for the Saturnian summer solstice occurring in May 2017. The northern summer solstice marks the beginning of summer in the northern hemisphere and winter in the southern hemisphere. Since Cassini arrived at Saturn just after the planet’s northern winter solstice, the extension will allow for the first study of a complete seasonal period.

    Cassini launched in October 1997 with the European Space Agency’s Huygens probe. The probe was equipped with six instruments to study Titan, Saturn’s largest moon. It landed on Titan’s surface on Jan. 14, 2005, and returned spectacular results.

    Meanwhile, Cassini’s 12 instruments have returned a daily stream of data from Saturn’s system since arriving at Saturn in 2004.

    Among the most important targets of the mission are the moons Titan and Enceladus, as well as some of Saturn’s other icy moons. Towards the end of the mission, Cassini will make closer studies of the planet and its rings.

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