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STORY WRITTEN FOR & USED WITH PERMISSIONPosted: January 21, 2005Liquid methane apparently falls like rain on Saturn's smog-shrouded moon Titan, washing down icy channels that ultimately spill into broad lakebeds dotted with ice islands and shoals, according to the latest data from Europe's Huygens probe. While the spacecraft did not detect any standing pools of liquefied natural gas in its immediate area, the data indicate rainfall is common on Titan and that liquid methane is present within a few inches of its surface. This mosaic of three frames provides unprecedented detail of the high ridge area including the flow down into a major river channel from different sources. Credits: ESA/NASA/JPL/University of ArizonaDownload larger image version "This isn't Mars, where the liquid that's done the erosion is buriedunderneath a solid," said Toby Owen, an interdisciplinary scientist with theCassini-Huygens mission. "This is a planet where the liquids are rightthere. It might have rained yesterday. This is really a very activesituation. That's the important news about detecting methane. It isn't thatwe think methane is there. It's really there in the liquid state."Said Martin Tomasko, principal investigator with the Huygens descentimager instrument: "What we know is the place we landed is dry at themoment. But the liquid is not 200 meters underground, the liquid was withina few centimeters of the surface, indicating that it must have rained notvery long ago. Does that mean yesterday or the day before, the week before?We don't really know. But the feeling is, in the place we landed, it mustrain fairly frequently. But we can't be more precise than that."NASA's Cassini Saturn orbiter released the Huygens probe on ChristmasEve. The small spacecraft, built by the European Space Agency, slammed intoTitan's thick nitrogen atmosphere Jan. 14 and descended by parachute to themoon's frozen surface, snapping pictures and sampling the atmosphere as itfell.Hitting the surface at about 11 mph, Huygens broke through a thincrust-like material and settled several inches into a spongy hydrocarbon"soil" with the consistency of loose sand. Nearby chunks of dirty water iceshow clear signs of fluid erosion, indicating the spacecraft landed in azone that at least occasionally experiences flowing liquids.At a news conference early today to unveil the latest data from Huygens,Owen said pre-landing predictions that liquid methane should exist on thesurface of the ultra-cold world - minus 290 degrees Fahrenheit at thesurface - were pretty much correct."What we've learned is that our speculation is really pretty good," Owensaid. "The main difference, the main new thing that we have is that indeed,we can detect liquid methane on the surface. It's not seas of liquid ethane,it's really liquid methane, liquid natural gas." A view of Titan from the VIMS instrument on the Cassini orbiter. The Huygens probe landed in the small red circle on the boundary of the bright and dark regions. The size of the circle shows the field of view of the Huygens DISR imager from an altitude of 20 kilometres. Credits: ESA/NASA/JPL/University of ArizonaDownload larger image version Tomasko provided a fresh interpretation of a picture released last weekshowing what appeared to be channels in elevated terrain bordered by anapparent shoreline.Stereo images show a ridge system in the image is more than 300 feetabove the surrounding terrain. Dark channels can be seen in the light-coloredelevated terrain leading to larger river bed-like features that empty into abasin.After studying the images for a week, Tomasko said his team believes thechannels "really are evidence of rain.""These branching, dendritic channels are evidence of rain and the darkmaterial in the bottoms of the channels is very likely this photochemicalsmog that falls out of the atmosphere, coats the whole terrain and getspreferentially washed off the top of the ridges," he said."The top of the ridges are ... not really very bright, they're relativelydark, but the dark material is definitely concentrated in the bottom ofthese drainage channels. And these ridges, we think, are made not ofsilicate rocks as on the Earth, but frozen, hard water ice. So we thinkwe're seeing water ice ridges washed off by rainfall with a liquid and aconcentration of these organic materials in the bottom of the (channels)."Looking at a larger mosaic that included the original picture, Tomaskosaid "we see this river system which flows down into this delta, into thislow-lying terrain. We see this ridge draining from the back and thesedendritic structures and then coming down from the front draining also intothis broad, low-lying terrain."In a new picture released today, Tomasko described additional featuresthat indicate flowing liquids, including short, stubby channels that couldindicate methane springs and areas that might be extrusions of water ice.Another photo showed a thin ridge in one of the pool-like basins that hadmultiple channels cut through it, presumably from erosion, giving theappearance of a chain of islands. A single image from the Huygens DISR instrument of a dark plain area on Titan, seen during descent to the landing site, that indicates flow around bright 'islands'. The areas below and above the bright islands may be at different elevations. Credits: ESA/NASA/JPL/University of Arizona"So there's lots of evidence of fluid flow, there's lots of evidence ofthis dark material, there's some evidence of water ice extrusion as well,"Tomasko said. "We don't think we see liquids in these areas, but we do thinkthere's plenty of evidence that there was flowing fluids on the surface ofTitan."For methane be present in the atmosphere today, it must be constantlyreplenished. Owen said the source of the methane was Titan itself."The photochemistry is happening up above, breaking methane apart,fragments are combining, making more complex things, making these smogparticles and they're precipitating down to the surface," he said. "Themethane, as we expected from the beginning, must condense because it's socold on the surface of Titan that we would expect liquid natural gas to bepresent there. And now the question is, is it really there?"Data from Huygens shows nitrogen is the dominant gas in the upperatmosphere of Titan. But as the probe descended, methane concentrations shotup."This is just like what happens on the Earth with water vapor," Owensaid. "Water on Earth is confined to the lower atmosphere. ... The reasonis, there's a very low temperature point in the atmosphere and there's thesame thing on Titan, there's a kind of cold trap that forces the methane tobe down below so that the methane increases more rapidly than the nitrogenas you go down into the lower atmosphere. That's where it is."Now, when you come to the surface, you would expect everything to bestable and that's what the nitrogen indeed does. ... However, the methanesuddenly jumps up by about 30 percent. Boom, in three minutes, up it goes.That methane must be coming out of the ground and that's the exciting part.It means there's liquid methane very near the surface, maybe right on thesurface."Tomasko said it's possible Huygens landed in Titan's equivalent of anarid region on Earth."We don't think we have open pools of liquid methane, but the methanekind of sinks down into the surface material," he said. "It's more likeArizona or someplace like that where the river beds are dry most of the timebut after rain, you might have open flowing liquids and pools. These poolsgradually dry out, the liquid sinks down into the surface. Perhaps it's veryseasonal."No one yet knows. But Jean-Pierre Lebreton, the Huygens mission scientistfor the European Space Agency, said Titan would make an ideal target forsome future robot lander.Video coverage for subscribers only:VIDEO:FRIDAY'S PHOTO & SCIENCE BRIEFING VIDEO:PICTURES PRESENTED WITH EXPERT NARRATION VIDEO:LISTEN TO SOUNDS FROM HUYGENS WITH NARRATION AUDIO:LISTEN TO SOUNDS FROM HUYGENS WITH NARRATION VIDEO:RESULTS FROM HUYGENS' SURFACE SCIENCE PACKAGE VIDEO:CHIEF SCIENTIST EXPLAINS COMMUNICATIONS ERROR VIDEO:SATURDAY PHOTO & SCIENCE BRIEFING AUDIO:SATURDAY PHOTO & SCIENCE BRIEFING VIDEO:THE FIRST PICTURE FROM HUYGENS IS REVEALED VIDEO:HUYGENS POST-LANDING NEWS BRIEFING VIDEO:STATUS REPORT DURING DESCENT AUDIO:MISSION STATUS REPORT DURING DESCENT VIDEO:HUYGENS PRE-ARRIVAL NEWS BRIEFING AUDIO:HUYGENS PRE-ARRIVAL NEWS BRIEFING VIDEO:OVERVIEW OF HUYGENS PROBE'S SCIENCE OBJECTIVES VIDEO:JULY NEWS BRIEFING ON CASSINI'S PICTURES OF TITAN VIDEO:PICTURES SHOWING TITAN SURFACE FROM OCT. FLYBY VIDEO:WHAT'S KNOWN ABOUT TITAN BEFORE THE FIRST FLYBY VIDEO:NARRATED MOVIE OF CLOUDS MOVING NEAR SOUTH POLE VIDEO:OCT. BRIEFING ON RADAR IMAGES OF TITAN SURFACE Ares 1-X PatchThe official embroidered patch for the Ares 1-X rocket test flight, is available for purchase.Apollo CollageThis beautiful one piece set features the Apollo program emblem surrounded by the individual mission logos.Expedition 21The official embroidered patch for the International Space Station Expedition 21 crew is now available from our stores.Hubble PatchThe official embroidered patch for mission STS-125, the space shuttle's last planned service call to the Hubble Space Telescope, is available for purchase. | | | | 2014 Spaceflight Now Inc.Spaceflight Now +Premium video content for our Spaceflight Now Plus subscribers.First picturesThe first pictures taken by Cassini during this close encounter with Titan are received at the Jet Propulsion Laboratory to the delight of the mission's imaging leader. (2min 21sec file)Images flood inA Cassini mission scientist provides analysis as the raw images taken of Titan's surface flood into the Jet Propulsion Laboratory. (29min 29sec file)Flyby explainedDetailed animation illustrates Cassini's flyby of Titan and how the probe's instruments will study this moon of Saturn. Expert narration is provided by a project official. (3min 09sec file)Titan knowledgeKnowledge about the mysterious moon Titan prior to this first close encounter is described by the Cassini mission's imaging leader. (6min 46sec file)Moving cloudsClouds near the south pole of Titan can be seen moving in this collection of pictures from Cassini as narrated by the mission's imaging leader. (2min 12sec file)Picture processingHow Cassini's raw pictures are processed by scientists is explained in this interview with the mission imaging leader. (5min 56sec file)Titan's purple covering points to a fuzzy past CASSINI PHOTO RELEASEPosted: July 30, 2004Encircled in purple stratospheric haze, Saturn's largest moon, Titan, appears as a softly glowing sphere in this colorized image taken on July 3, 2004, one day after Cassini's first flyby of that moon. Titan has a dense atmosphere composed primarily of nitrogen with a few percent methane. The atmosphere can undergo photochemical processes to form hazes. Credit: NASA/JPL/Space Science InstituteDownload a larger version of image Images like this one reveal some of the key steps in the formation and evolution of Titan's haze. The process is thought to begin in the high atmosphere, at altitudes above 400 kilometers (250 miles), where ultraviolet light breaks down methane and nitrogen molecules. The products are believed to react to form more complex organic molecules containing carbon, hydrogen and nitrogen that can combine to form the very small particles seen as haze.This ultraviolet view of Titan has been falsely colored. The main body is colored pale orange as seen in true color images. Above the orange disc are two distinct layers of atmospheric haze that have been brightened and falsely colored violet to enhance their visibility. It is not currently understood why there are two separate haze layers. This and other questions await answers as the four-year Cassini tour continues, with many more planned flybys of Titan. The upcoming October 2004 flyby of Titan will be 30 times closer than that of July 2.The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Office of Space Science, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.Ares 1-X PatchThe official embroidered patch for the Ares 1-X rocket test flight, is available for purchase.Apollo CollageThis beautiful one piece set features the Apollo program emblem surrounded by the individual mission logos.Expedition 21The official embroidered patch for the International Space Station Expedition 21 crew is now available from our stores.Hubble PatchThe official embroidered patch for mission STS-125, the space shuttle's last planned service call to the Hubble Space Telescope, is available for purchase. | | | | 2014 Spaceflight Now Inc.Two views of Titan's haze CASSINI PHOTO RELEASEPosted: October 28, 2004 Credit: NASA/JPL/Space Science InstituteDownload larger image version These images show two views of Titan's planet-wide stratospheric haze just before (left) and after (right) Cassini's first close encounter with the shrouded moon.The image on the left was taken on Oct. 25, 2004, through an ultraviolet filter, which is sensitive to scattering of sunlight by small haze particles. It shows the high-altitude haze at the north pole (top) illuminated above a surface blanketed in darkness during this winter season. Numerous striations are visible in the haze, indicating either waves passing through the layer or the presence of multiple layers. The pixel scale of this image is 2.8 kilometers (1.7 miles). The image on the right was taken on Oct. 26, 2004, and shows Titan's night-side backlit by the Sun after Cassini's closest approach to the moon. The haze layer ringing the planet is illuminated because the small particles scatter significant sunlight in the forward direction. Variations in haze concentration and thickness around the globe are also evident and seem to be symmetric around the north pole (upper left). The pixel scale of this image is 6.6 kilometers (4.1 miles). The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. Cassini posterJust in time for the Cassini spacecraft's arrival at Saturn, this new poster celebrates the mission to explore the ringed planet and its moons. 2005 CalendarThe 2005 edition of the Universe of the Hubble Space Telescope calendar is available from our U.S. store and will soon be available worldwide. This 12x12-inch calendar features spectacular images from the orbiting observatory.Moon panoramaTaken by Apollo 14 commander Alan Shepard, this panoramic poster shows lunar module pilot Edgar Mitchell as a brilliant Sun glare reflects off the lunar module Antares.Mars Rover mission patchA mission patch featuring NASA's Mars Exploration Rover is now available from the Astronomy Now Store. | | | | 2014 Spaceflight Now Inc.Ultraviolet pictures hint at origin of Saturn's rings UNIVERSITY OF COLORADO NEWS RELEASEPosted: July 7, 2004The best view ever of Saturn's rings in the ultraviolet indicates there is more ice toward the outer part of the rings, hinting at ring origin and evolution, say two University of Colorado at Boulder researchers involved in the Cassini mission. From the inside out, the "Cassini division" in faint red at left is followed by the A ring in its entirety. The A ring begins with a "dirty" interior of red followed by a general pattern of more turquoise as it spreads away from the planet, which indicates denser material made up of ice. The red band roughly three-fourths of the way outward in the A ring is known as the Encke gap.Download a larger image version Researchers from CU-Boulder's Laboratory for Atmospheric and Space Physics, Joshua Colwell and Larry Esposito, said the UV spectra taken during the Cassini spacecraft's orbital insertion June 30 show definite compositional variation in the A, B and C rings.Esposito, who discovered the F ring around Saturn in 1979 using Pioneer 11 data, is the team leader for Cassini's Ultraviolet Imaging Spectrograph, or UVIS, a $12.5 million instrument riding on the spacecraft. A UVIS team member and ring expert, Colwell created the color-enhanced images from the spectra.The CU-Boulder built UVIS instrument is capable of resolving the rings to show features up to 60 miles across, roughly 10 times the resolution obtained by the Voyager 2 spacecraft. The instrument was able to resolve the "Cassini division," discovered by Giovanni Domenico Cassini in the 17th century, which separates the A and B rings of Saturn, proving the rings are not one contiguous feature.The ring system begins from the inside out with the D, C, B and A rings followed by the F, G and E rings. The red in both images indicates sparser ringlets likely made of "dirty," and possibly smaller, particles than in the denser, icier turquoise ringlets. This image shows the outer C and inner B rings respectively from left to right, with the inner B ring beginning a little more than halfway across the image. The general pattern is from "dirty" red particles to the denser ice shown in turquoise as the ringlets spread outward.Download a larger image version Additional coverage for subscribers:VIDEO:WATCH SATURDAY'S NEWS CONFERENCE ON TITAN PICTURES VIDEO:WATCH FRIDAY'S SCIENCE NEWS CONFERENCE VIDEO:THURSDAY'S NEWS BRIEFING ON CASSINI'S FIRST PICTURES VIDEO:RING PICTURES ARE PRESENTED WITH EXPERT NARRATION VIDEO:CASSINI RE-DISCOVERS TINY MOONS ATLAS AND PAN VIDEO:CASSINI BOOMING SOUNDS FROM BOW-SHOCK CROSSING VIDEO:CASSINI BEGINS ENGINE FIRING TO ENTER ORBIT VIDEO:BURN ENDS SUCCESSFULLY TO PUT CASSINI IN ORBIT VIDEO:POST-ARRIVAL NEWS CONFERENCE VIDEO:WEDNESDAY'S 12 P.M. EDT CASSINI STATUS BRIEFING VIDEO:A LOOK AT INTERNATIONAL COOPERATION VIDEO:'RING-SIDE CHAT' ABOUT SPACE EXPLORATION VIDEO:AN OVERVIEW OF CASSINI'S RADIO SCIENCE VIDEO:TUESDAY'S CASSINI MISSION OVERVIEW BRIEFING VIDEO:CASSINI'S ARRIVAL AT SATURN EXPLAINED VIDEO:SCIENCE OBJECTIVES FOR CASSINI ORBITER VIDEO:HUYGENS LANDER SCIENCE OBJECTIVES Gemini 7Gemini 7: The NASA Mission Reports covers this 14-day mission by Borman and Lovell as they demonstrated some of the more essential facts of space flight. Includes CD-ROM.Choose your store: - - - Apollo patchesThe Apollo Patch Collection: Includes all 12 Apollo mission patches plus the Apollo Program Patch. Save over 20% off the Individual price. Choose your store: - - - Mars Rover mission patchA mission patch featuring NASA's Mars Exploration Rover is available from our online.Choose your store: - - - Apollo 9 DVDOn the road to the moon, the mission of Apollo 9 stands as an important gateway in experience and procedures. This 2-DVD collection presents the crucial mission on the voyage to the moon. Choose your store: - - - Ares 1-X PatchThe official embroidered patch for the Ares 1-X rocket test flight, is available for purchase.Apollo CollageThis beautiful one piece set features the Apollo program emblem surrounded by the individual mission logos.Expedition 21The official embroidered patch for the International Space Station Expedition 21 crew is now available from our stores.Hubble PatchThe official embroidered patch for mission STS-125, the space shuttle's last planned service call to the Hubble Space Telescope, is available for purchase. | | | | 2014 Spaceflight Now Inc.Winds measured on Saturn's moon Titan to help lander NASA-GSFC NEWS RELEASEPosted: June 29, 2004On top the windswept summit of a Hawaiian volcano, a NASA instrument attached to the Japanese Subaru telescope measured distant winds raging on a strange world -- Titan, the giant moon of Saturn -- to help the robotic Huygens probe as it descends through Titan's murky atmosphere next January.When combined with previous observations, new research with the Heterodyne Instrument for Planetary Wind And Composition (HIPWAC) joined to the large aperture of the Subaru telescope supports the model that Titan has currents or jet streams at high latitudes racing through its upper atmosphere (stratosphere) at speeds of approximately 756 km/hour (470 miles/hr.). The new observations reveal that the wind travels in the same direction as Titan's rotation, and that the stratospheric winds are milder (about 425 km/hr. or 264 miles/hr.) near the equatorial regions, as the jet stream model predicts. HIPWAC was designed and built at NASA's Goddard Space Flight Center in Greenbelt, Md. The Subaru telescope is operated by the National Astronomical Observatory of Japan.Wind direction on Titan is difficult to measure remotely because Titan?? upper atmosphere consists of an orange haze of hydrocarbons (molecules of hydrogen and carbon) with no global features that show movement.The observations were originally encouraged by the Cassini mission, an international mission of NASA, the European Space Agency (ESA) and the Italian Space Agency (ASI) that will employ a large robotic spacecraft to explore Saturn and its system of 31 known moons beginning this July. The Huygens probe, built by ESA, is attached to the Cassini spacecraft and will separate in December on a 22-day course ending with a plunge into Titan's atmosphere. NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages the Cassini mission for NASA."Our observations will complement local wind measurements by the Huygens probe during its descent, because we offer a global view. Acquiring the direction and speed of global winds is important for understanding the dynamics of planetary atmospheres, particularly dynamics of those bodies that rotate slowly on their axes. Titan?? 'day' is 16 Earth days," said Dr. Theodor Kostiuk of NASA Goddard."We hope to be able to repeat our success during the probe?? descent so we can have detailed local information from Cassini and the Huygens probe and a global portrait from HIPWAC and Subaru from the same time," said Professor Hiroshi Karoji, Director of the Subaru telescope, Mauna Kea, Hawaii.Titan, the second largest moon in the solar system, is larger than the planet Mercury and is the only known moon with a thick atmosphere, actually 1.5 times more dense than Earth's. Because it is far from the Sun, Titan is extremely cold (surface temperature of about minus 178 Celsius (minus 289 Fahrenheit), allowing a hydrocarbon rain that may form gasoline-like seas. Scientists are eager to explore Titan because its atmosphere may resemble the Earth's atmosphere shortly after our planet's formation, when it was rich with hydrocarbon molecules that became the building blocks of life.HIPWAC can measure wind speed and direction on Titan, even though the moon's atmosphere lacks apparent features, because the instrument relies instead on the faint, infrared glow of the hydrocarbons in Titan's atmosphere. Infrared light, invisible to the human eye, can pass through Titan's hydrocarbon haze and is detectable by special instruments. HIPWAC measures the very slight color (frequency) change of the hydrocarbon's infrared light caused by the motion of these molecules as they are carried by Titan's winds. This is called a Doppler shift, and is similar to the change in tone of an ambulance siren as it races by. Since the hydrocarbons are moved along by Titan's winds, the Doppler shift of their emitted light gives the wind velocity.To measure such miniscule Doppler shifts, HIPWAC must be capable of distinguishing among infrared colors, or frequencies, to a very fine degree. This is called spectral resolution, and HIPWAC possesses a spectral resolution 200 times better than any instrument in regular use today. It also must measure specific infrared frequencies very accurately, and HIPWAC can identify a frequency to one part in a hundred million.Subaru telescope brings to HIPWAC the light gathering power of a modern large aperture telescope. Subaru?? 8.2-meter (27- foot) diameter mirror is the largest single-piece mirror in the world that is currently in regular operation. Since HIPWAC achieves its high spectral resolution by finely dividing light into different frequencies, the more light it has to work with the better. Other institutions contributing to this research include the Challenger Center for Space Science Education, University of Maryland, University of Hawaii, and the University of Cologne, Germany.Ares 1-X PatchThe official embroidered patch for the Ares 1-X rocket test flight, is available for purchase.Apollo CollageThis beautiful one piece set features the Apollo program emblem surrounded by the individual mission logos.Expedition 21The official embroidered patch for the International Space Station Expedition 21 crew is now available from our stores.Hubble PatchThe official embroidered patch for mission STS-125, the space shuttle's last planned service call to the Hubble Space Telescope, is available for purchase. | | | | 2014 Spaceflight Now Inc.Cassini Mission ReportWelcome to Spaceflight Now's mission page covering the Cassini space probe's exploration of Saturn, its remarkable rings and numerous moons. You can check this page for our stories, NASA's picture releases and mission status reports. us your comments, suggestions and corrections!Top StoriesObservatory watched Titan when Huygens arrivedThe Huygens probe impacted Titan's atmosphere Friday, with an expected landing on Titan's mysterious surface three hours later. This near-infrared image shows Titan at the moment Huygens reached its target as seen from the Keck Observatory on Earth.Scientists elated with quality of Huygens dataA missing computer command - apparently the result of human error - caused the loss of half the pictures taken by Europe's Huygens probe as it descended to the surface of Saturn's moon Titan. But project officials said Saturday the 350 pictures that made it back, along with high-quality data fromthe spacecraft's other instruments and unexpected measurements by Earth-based radio telescopes, should fulfill all of the mission's primary objectives.PHOTO: Surface of Saturn's moon Titan revealed in colorTired and weary after a sleepless night spent sorting through their data, scientists on Saturday unveiled more pictures returned from the European Space Agency's Huygens probe that landed on Saturn's moon Titan Friday.PHOTO: PHOTO: PHOTO: PHOTO: Video coverage for subscribers only:VIDEO:THE NEW PICTURES PRESENTED WITH EXPERT NARRATION VIDEO:LISTEN TO SOUNDS FROM HUYGENS WITH NARRATION AUDIO:LISTEN TO SOUNDS FROM HUYGENS WITH NARRATION VIDEO:RESULTS FROM HUYGENS' SURFACE SCIENCE PACKAGE VIDEO:CHIEF SCIENTIST EXPLAINS COMMUNICATIONS ERROR VIDEO:SATURDAY PHOTO & SCIENCE BRIEFING AUDIO:SATURDAY PHOTO & SCIENCE BRIEFING European probe becomes Titan's first visitorThe European Space Agency's ambitious Huygens probe descended to Saturn's moon Titan Friday, becoming the first spacecraft to touch the mysterious world's surface. Titan is believed to resemble conditions of a young Earth. A mission scientist says the first picture released shows what could be drainage channels flowing to a possible shoreline.Video coverage for subscribers only:VIDEO:THE FIRST PICTURE FROM HUYGENS IS REVEALED VIDEO:OFFICIALS OFFER THOUGHTS AFTER SEEING PICTURE VIDEO:HUYGENS POST-LANDING BRIEFING AUDIO:HUYGENS POST-LANDING BRIEFING VIDEO:STATUS REPORT DURING DESCENT AUDIO:MISSION STATUS REPORT DURING DESCENT VIDEO:HUYGENS PRE-ARRIVAL NEWS BRIEFING AUDIO:HUYGENS PRE-ARRIVAL NEWS BRIEFING VIDEO:OVERVIEW OF HUYGENS PROBE'S SCIENCE OBJECTIVES VIDEO:JULY NEWS BRIEFING ON CASSINI'S PICTURES OF TITAN VIDEO:PICTURES SHOWING TITAN SURFACE FROM OCT. FLYBY VIDEO:WHAT'S KNOWN ABOUT TITAN BEFORE THE FIRST FLYBY VIDEO:NARRATED MOVIE OF CLOUDS MOVING NEAR SOUTH POLE VIDEO:OCT. BRIEFING ON RADAR IMAGES OF TITAN SURFACE Scientists await landingThe European Space Agency's Huygens probe, closing in on Saturn's mysterious moon Titan, is racing toward a dramatic, high-speed plunge into the moon's thick nitrogen atmosphere after 5 a.m. EST (1000 GMT) Friday. The flying saucer-shaped probe is expected to endure peak heating of nearly 3,500 degrees and a braking force of some 16 Gs. - live updates!Video coverage for subscribers only:VIDEO:HUYGENS PRE-ARRIVAL NEWS BRIEFING AUDIO:HUYGENS PRE-ARRIVAL NEWS BRIEFING Probe travels to surface of Saturn's moon Titan FridayIn one of the boldest space missions ever attempted, a small European-built probe will slam into the atmosphere of Saturn's mysterious moon Titan Friday for a two-and-a-half hour parachute descent to its smog-shrouded surface.Video coverage for subscribers only:VIDEO:OVERVIEW OF HUYGENS PROBE'S SCIENCE OBJECTIVES VIDEO:JULY NEWS BRIEFING ON CASSINI'S PICTURES OF TITAN VIDEO:PICTURES SHOWING TITAN SURFACE FROM OCT. FLYBY VIDEO:WHAT'S KNOWN ABOUT TITAN BEFORE THE FIRST FLYBY VIDEO:NARRATED MOVIE OF CLOUDS MOVING NEAR SOUTH POLE VIDEO:OCT. BRIEFING ON RADAR IMAGES OF TITAN SURFACE Encountering IapetusOn New Year's Eve 2004, Cassini flew past Saturn's intriguing moon Iapetus, capturing images that were put together to form this global view. The scene is dominated by a dark, heavily-cratered region, called Cassini Regio, that covers nearly an entire hemisphere of Iapetus.Iapetus: View from the topThis oblique view of Saturn's moon Iapetus from high latitude shows how the dark, heavily cratered terrain of Cassini Regio transitions to a bright, icy terrain.Giant landslide on IapetusA spectacular landslide within the low-brightness region of Iapetus's surface known as Cassini Regio is visible in this image from Cassini. The landslide material appears to have collapsed from a scarp 9 miles high that forms the rim of an ancient 375-mile impact basin.Fresh crater on Rhea?Rhea has been heavily bombarded by impacts during its history. In this Cassini image the moon around Saturn displays what may be a relatively fresh, bright, rayed crater near Rhea's eastern limb. Rhea is 949 miles across.Cassini diverts from collision course with moonNASA's Cassini spacecraft successfully performed a getaway maneuver to keep it from following the Huygens probe into the atmosphere of Saturn's moon Titan. The probe has no navigating capability, so the Cassini orbiter had been placed on a deliberate collision course with Titan to ensure the accurate delivery of the probe to the moon.Cassini takes picture of departing Huygens probeThe Cassini spacecraft snapped this image of the European Space Agency's Huygens probe about 12 hours after its release from the orbiter. The probe successfully detached from Cassini on Friday night and is on course for its January 14 encounter with Titan. Radio telescopes will add to Huygens discoveriesWhen the Huygens spacecraft makes its plunge into the atmosphere of Saturn's moon Titan on January 14, radio telescopes of the National Science Foundation's National Radio Astronomy Observatory will help international teams of scientists extract the maximum possible amount of irreplaceable information from an experiment unique in human history.Cassini orbiter deploys Titan descent probeIn a long-awaited milestone, a European-built probe carrying cameras and a suite of scientific instruments was released from NASA's Cassini Saturn orbiter Christmas Eve, setting up a dramatic Jan. 14 plunge into the atmosphere of the ringed planet's mysterious moon Titan. - updated @ 12:50 a.m. ESTSaturn lightning, rotation discoveries madeAs NASA's Cassini spacecraft approached Saturn last July, it found evidence that lightning on the planet is roughly one million times stronger than lightning on Earth.New clouds add to mystery of Saturn's moon TitanUsing adaptive optics on the Gemini North and Keck II telescopes on Mauna Kea, Hawai'i, a U.S. team has discovered a new phenomenon in the atmosphere of Saturn's largest moon Titan. Unlike previous observations showing storms at the south pole, these new images reveal atmospheric disturbances at Titan's temperate mid latitudes - about halfway between the equator and the poles.Saturn's outer rings may be eroding, Cassini data showsA massive eruption of atomic oxygen from Saturn's outer rings, seen by Cassini's ultraviolet camera as the spacecraft neared its destination, may be an indication that the planet's wispy E ring is eroding so fast that it could disappear within 100 million years if not replenished.Before and after look at Saturn's moon TitanCassini's second close flyby of Titan completes a 'before' and 'after' look at the fuzzy moon and provides the first direct evidence of changing weather patterns in the skies over Titan.Cassini has another successful Titan flybyThe Cassini spacecraft completed a successful rendezvous with Saturn's moon Titan on Monday. This was the last pass before the European Space Agency's Huygens probe is sprung loose from Cassini on Christmas Eve.New Cassini picture shows rings in extraordinary detailThis fantastic close-up of Saturn's outer C ring shows large and sharp changes in brightness across the rings, owing to the extreme variations in ring particle concentrations at different distances from the planet.From Saturn's dark sideAs Cassini swung around to the dark side of the planet during its first close passage after orbit insertion, the intrepid spacecraft spied three ring moons -- Mimas, Janus and Prometheus -- whizzing around the planet.Saturn's moon Iapetus as you've never seen itNew details on Iapetus are illuminated by reflected light from Saturn in this revealing Cassini image. Never-before-seen features on the Saturn-facing part of Iapetus' bright trailing hemisphere are visible for the first time.Cassini captures Saturn moon red-handedStealing is a crime on Earth, but at Saturn, apparently it is routine. The Cassini spacecraft has witnessed Saturn's moon Prometheus snatching particles from one of Saturn's rings.Saturn's ring gapAn intriguing knotted ringlet within the Encke Gap is the main attraction in this Cassini image. The Encke Gap is a small division near the outer edge of Saturn's rings that is about 190 miles wide. The tiny moon Pan orbits within the gap and maintains it.Gazing down on SaturnThe Cassini spacecraft pierced the ring plane and rounded Saturn a few weeks ago, capturing these pictures that NASA has released showing the dark portion of the planet's majestic rings.Nature's canvas at SaturnIn a splendid portrait created by light and gravity, Saturn's lonely moon Mimas is seen against the cool, blue-streaked backdrop of Saturn's northern hemisphere. Delicate shadows cast by the rings arc gracefully across the planet, fading into darkness on Saturn's night side.Battered and grooved: Saturn's moon TethysHaving now passed closer to Tethys than the Voyager 2 spacecraft, Cassini has returned the best-ever natural color view of this icy Saturnian moon.Hovering over TitanA mosaic of nine processed images recently acquired during Cassini's first very close flyby of Saturn's moon Titan constitutes the most detailed full-disc view of the mysterious moon. The mosaic was released this week.Breathtaking vista of TethysThis dazzling view from Cassini looks beyond gigantic storms near Saturn's south pole to the small but clear disc of Tethys. Clouds and ribbons of gas swirl about in the planet's atmosphere in the foreground, while a tremendous chasm is visible on the icy moon.Cassini image shows Saturn moon with a real shinerSaturn's moon Rhea shows off the moon equivalent of a black eye -- a bright, rayed crater near its eastern limb -- in this picture from the Cassini mission released Monday. Rhea is about half the size of Earth's moon.Cassini sees Atlas, Pandora and Janus orbiting SaturnSaturn hosts its own miniature solar system, with an entourage of more than 30 moons. This image shows Saturn's A and F rings, along with three of the moons that orbit close to them.Objects, density waves seen in Saturn's ringsA University of Colorado at Boulder-built instrument riding on the Cassini-Huygens spacecraft is being used to resolve objects in Saturn's rings smaller than a football field, making them twice as sharp as any previous ring observations.Cassini observations show dynamic dance at SaturnA University of Colorado at Boulder professor involved with the Cassini-Huygens mission is reporting an ever-changing vista at the frontiers of Saturn, featuring wayward moons, colliding meteoroids, rippling rings and flickering auroras.Cassini radar sees flow-like feature across TitanA strikingly bright, lobate feature has turned up in one of Cassini's first radar images of Saturn's moon Titan. It looks like something that "oozed across the surface," says a radar team member.Crunch, squelch or splash on Saturn's moon Titan?The prospect of the Huygens probe landing on a hard, soft or liquid surface when it lands on Titan next January still remain following further analysis of data taken during the Cassini mother ship's closest encounter with Saturn's largest moon during its fly-by on October 26.Radar image shows Titan's surface live and in colorSaturn's moon Titan shows a sharp contrast between its smooth and rough edges in a new false-color radar image. Titan's surface lies beneath a thick coat of hazy clouds, but Cassini's radar instrument can peer through to show finer surface features.Cassini's radar shows Titan's young active surfaceThe first radar images of Saturn's moon Titan show a very complex geological surface that may be relatively young. Previously, Titan's surface was hidden behind a veil of thick haze.Additional coverage for subscribers:VIDEO:THURSDAY'S BRIEFING ON RADAR IMAGES OF TITAN SURFACE Two views of Titan's hazeTitan's planet-wide stratospheric haze is observed in Cassini's first close encounter with the shrouded moon. This image shows Titan's night-side backlit by the Sun after the space probe's closest approach to the moon. The haze layer ringing the planet is illuminated because the small particles scatter significant sunlight in the forward direction.Scientists elated by Cassini's Titan observationsAfter years of anticipation, the Cassini spacecraft beamed back smog-piercing close-up images of Saturn's moon Titan late Tuesday, revealing a strange, striated landscape that both thrilled - and mystified - planetary scientists.Additional coverage for subscribers:VIDEO:WEDNESDAY'S POST-FLYBY SCIENCE NEWS CONFERENCE Cassini has close encounter with Saturn's moon TitanNASA's Cassini spacecraft streaked by Saturn's smoggy moon Titan Tuesday, targeted to pass within just 750 miles of the planet-sized satellite to give scientists their first detailed glimpse of a world that, until now, has been shrouded in mystery. A news conference to discuss the pictures and data is planned for 1600 GMT (12 noon EDT) Wednesday.Additional coverage for subscribers:VIDEO:FLYBY EXPLAINED IN DETAILED ANIMATION WITH NARRATION VIDEO:WHAT'S KNOWN ABOUT TITAN BEFORE THE FLYBY VIDEO:NARRATED MOVIE OF CLOUDS MOVING NEAR SOUTH POLE VIDEO:HOW CASSINI IMAGES ARE PROCESSED IS EXPLAINED Titan up closeThese raw, un-processed images of Saturn's moon Titan were taken by the Cassini spacecraft and transmitted to Earth on October 26. The pictures provide the closest views ever snapped of the hazy moon.Additional coverage for subscribers:VIDEO:FIRST PICTURES FROM FLYBY ARE RECEIVED AT JPL VIDEO:29-MINUTE MOVIE OF PICTURES SHOWING TITAN SURFACE Cassini flies past Titan; pictures expected tonightNASA's Cassini spacecraft streaked by Saturn's smoggy moon Titan Tuesday, targeted to pass within just 750 miles of the planet-sized satellite to give scientists their first detailed glimpse of a world that, until now, has been shrouded in mystery.Cassini scientists ready for first close Titan flybyThe Cassini spacecraft is heading for its first close encounter with Saturn's moon Titan. University of Arizona scientists on the mission say Cassini will get its first real glimpse of Titan surface geology and digest its first gulp of rich Titan air. The first pictures from the close flyby are expected late tonight.Eyes on XanaduThis stunning image taken Sunday reveals Titan's bright "continent-sized" terrain known as Xanadu. It was acquired with the narrow angle camera on Cassini as the craft sped toward its first close encounter with the moon of Saturn. Cassini yields new knowledge of Saturn's ringsAlthough Cassini has only been orbiting the planet Saturn since July 1, data from the Cassini Plasma Spectrometer has already begun to provide new information about the curious nature of Saturn's space environment.Cassini eyes the culpritGazing beyond Saturn's magnificent rings, Cassini spotted the cause of the dark gap visible in the foreground of this image: Mimas. The gravitational influence of Mimas is responsible for the 2,980 mile-wide Cassini division, which stretches across the lower left portion of this view. The little moon is at a nearly half-full phase in this view. Music rings of SaturnLooking something like the fibrous bow of a violin, Saturn's colorful rings sweep through this spectacular natural color view while two small moons look on. Herding Saturn's ringsSaturn's moon Prometheus is seen shepherding the inner edge of Saturn's F ring. Prometheus is 63 miles across and was captured in a close-up view by the Cassini spacecraft near the time of orbital insertion at Saturn. A number of clumps are visible here along the arcing F ring.Huygens test successfulThe European Space Agency's Huygens probe, now orbiting Saturn onboard the Cassini spacecraft, is in good health and successfully passed its fifteenth 'In-Flight Checkout' last week. This test procedure was the last but one planned before separation of the Huygens probe from Cassini in December.Colorful threads and shadows of SaturnSaturn's faintly banded atmosphere is delicately colored and its threadbare rings cross their own shadows in this marvelous natural color view from Cassini. Cassini orbiter snaps Saturn's family portraitA stately Saturn poses for a portrait with five of its moons in this Cassini spacecraft wide angle camera view. The moons visible include Dione, Enceladus, Tethys, Mimas and Rhea.Cassini discovers ring and one, maybe two, objectsScientists examining Saturn's contorted F ring, which has baffled them since its discovery, have found one small body, possibly two, orbiting in the F ring region, and a ring of material associated with Saturn's moon Atlas.Cassini spacecraft spies Saturn's moon IapetusThe dark material that coats one hemisphere of Saturn's moon Iapetus is very dark, as these two processed views of the same image demonstrate. Cassini craft reveals Saturn's cool ringsThe Cassini spacecraft has taken the most detailed temperature measurements to date of Saturn's rings. Data taken by the composite infrared spectrometer instrument on the spacecraft while entering Saturn's orbit show the cool and relatively warm regions of the rings.South polar storms on Saturn spotted by CassiniThis Cassini spacecraft narrow angle camera view of Saturn's southern polar region features a bright white spot, or storm, surrounded by faint, darker swirls of clouds. Cassini conducts major orbit adjustment maneuverThe Cassini spacecraft successfully completed a 51-minute engine burn that will raise its next closest approach distance to Saturn by nearly 186,000 miles. The maneuver was necessary to keep the spacecraft from passing through the rings and to put it on target for its first close encounter with Saturn's moon Titan on Oct. 26. Streaking away from DioneSaturn's crescent moon Dione hangs before the Cassini spacecraft in this magnified image. The icy moon shows a hint of the bright, wispy features that mark its surface.Latest color pictures from Cassini look like artworkNASA has released three new stunning color pictures taken by the Cassini spacecraft exploring the planet Saturn. The images show the giant planet, its golden rings and several moons.Out from the shadows: Two new Saturnian moonsWith eyes sharper than any that have peered at Saturn before, the Cassini spacecraft has uncovered two moons, which may be the smallest bodies so far seen around the ringed planet.Newest picture from Cassini shows Saturn in colorA frigid ball of gas in the blackness of space, Cassini's new home, Saturn, appears cool and serene in this natural color image. The spacecraft obtained this view as it sped outward from the planet on its initial orbit. At the left, Saturn's shadow stretches almost completely across the rings, while at the right, the planet's illuminated face appears to gaze down at the far-off Sun.Cassini discoveries shed light on Saturn and TitanThe Cassini spacecraft, which began its tour of the Saturn system just over a month ago, has detected lightning and a new radiation belt at Saturn, and a glow around the planet's largest moon, Titan.South polar structure of Saturn imaged by CassiniSaturn's southern polar region exhibits concentric rings of clouds which encircle a dark spot at the pole. To the north and toward the right, wavy patterns are evident, resulting from the atmosphere moving with different speeds at different latitudes.Saturn in full view for Cassini spacecraftTwo weeks after orbit insertion, Cassini glanced back at Saturn, taking in the entire planet and its expansive rings. Currently it is summer in Saturn's southern hemisphere. Notable here is the bright spot located near the planet's southern hemisphere, where the line from the day and night side of the planet meets. The angle of illumination hints at Saturn's tilt relative to the Sun.Titan's purple covering points to a fuzzy pastEncircled in purple stratospheric haze, Saturn's largest moon, Titan, appears as a softly glowing sphere in this colorized image taken on July 3, one day after Cassini's first flyby of that moon. Titan has a dense atmosphere composed primarily of nitrogen with a few percent methane. The atmosphere can undergo photochemical processes to form hazes.Hazy all over TitanFollowing its first flyby of Titan, Cassini gazed back at the smog-enshrouded moon's receding crescent. This natural color view was seen by the spacecraft about one day after closest approach. The slight bluish glow of Titan's haze is visible along the limb.Cassini's rear-view image of Saturn's moon TitanA day after entering orbit around Saturn, Cassini sped silently past Titan, imaging the moon's south polar region. This natural color image represents Cassini's view only about two hours after closest approach to the moon.Odd-looking moon Mimas photographed by CassiniSoon after orbital insertion, Cassini returned its best look yet at heavily cratered Mimas. The enormous crater at the top of this image, named Herschel, is about 80 miles wide and 6 miles deep.Cassini sees the moon Tethys: The Sea GoddessLike a half-full moon, cratered Tethys hangs before the Cassini spacecraft in this narrow angle camera view. Voyager images showed a large fracture on Tethys about 470 miles long. Cassini will investigate this and other features on Tethys during two planned flybys beginning next year.Stunning true-color picture of Saturn's ringsWith shimmering pinks, hues of gray and a hint of brown, a newly released image of Saturn's rings resembles a fresco where nature is the painter. The Cassini spacecraft captured this exquisite natural color view a few days before entering orbit around Saturn.Cassini sees crescent RheaThe first artificial satellite in the Saturn system, the Cassini spacecraft, returned images of the natural moons following a successful insertion into orbit. This is an unmagnified view of the moon Rhea.Cassini shows the dark side of Saturn's moon DioneThe icy, cratered surface of Saturn's moon Dione shows more than just its sunlit side in these two processed versions of the same image from the Cassini spacecraft.Cassini exposes Saturn's two-face moon IapetusThe moon with the split personality, Iapetus, presents a perplexing appearance in the latest images snapped by the Cassini spacecraft. One hemisphere of the moon is very dark, while the other is very bright. Scientists do not yet know the origin of the dark material or whether or not it is representative of the interior of Iapetus.South pole on SaturnDetails observed in Saturn's south polar region by Cassini demonstrate that this area is far from featureless. Lighter colored clouds dot the entire region, which is dominated by a central, sharply-defined circular feature.Cassini spacecraft's solar conjunction endsThe Cassini spacecraft emerged from behind the Sun on Monday after being in solar conjunction since July 5. The most recent spacecraft telemetry was acquired from the Deep Space Network's Goldstone tracking station. The spacecraft is in excellent health and operating normally.Ultraviolet pictures hint at origin of Saturn's ringsThe best view ever of Saturn's rings in the ultraviolet indicates there is more ice toward the outer part of the rings, hinting at ring origin and evolution, say two University of Colorado at Boulder researchers involved in the Cassini mission. [Posted: July 7]Cassini close ups of Titan thrill, mystify scientistsNew pictures of Saturn's enigmatic moon Titan, taken by cameras aboard the Cassini probe show strange looking surface features and a deck of methane clouds the size of Arizona. But so far, the instruments have not detected reflections from the surfaces of lakes or small seas of liquid hydrocarbons many scientists believe must form in the ultra-cold environment. [Posted: July 3]Additional coverage for subscribers:VIDEO:WATCH SATURDAY'S NEWS CONFERENCE ON TITAN PICTURES Cassini finds puzzles in Saturn's ring ingredientsJust two days after the Cassini spacecraft entered Saturn orbit, preliminary science results are already beginning to show a complex and fascinating planetary system. One early result intriguing scientists concerns Saturn's Cassini Division, the large gap between the A and B rings. [Posted: July 2]Additional coverage for subscribers:VIDEO:WATCH FRIDAY'S SCIENCE NEWS CONFERENCE Reading tale of ions in Saturn's magnetosphereThe Cassini spacecraft has barely begun its four-year tour around Saturn, but already a University of Maryland sensor is beginning to reveal new data about the immense magnetosphere of the ringed planet. [Posted: July 2]Scientists marvel at photosMaking gravity visible, close-up images of Saturn's rings shot by NASA's newly arrived Cassini probe revealed an intricate, never-before-seen tapestry of icy particles herded into spiralling density waves by the effects of nearby moons. [Posted: July 1]Additional coverage for subscribers:VIDEO:TODAY'S NEWS CONFERENCE ON CASSINI'S FIRST PICTURES VIDEO:RING PICTURES ARE PRESENTED WITH EXPERT NARRATION VIDEO:CASSINI RE-DISCOVERS TINY MOONS ATLAS AND PAN VIDEO:CASSINI BOOMING SOUNDS FROM BOW-SHOCK CROSSING Welcome to Saturn!NASA's $3.3 billion Cassini probe completed a seven-year, 2.2-billion mile voyage Wednesday night, firing its main engine for a nerve-wracking 96 minutes to successfully brake into orbit around the ringed planet Saturn. [Posted: July 1] - updates!First pictures from Saturn orbit show rich ring detailThe first batch of photographs snapped by the Cassini Saturn orbiter earlier today reached the Jet Propulsion Laboratory around 8:30 a.m. EDT, zoomed-in shots of the planet's myriad rings showing a ghostly tapestry of icy, back-lit particles arrayed in sharply defined bands. [Posted: July 1]Additional coverage for subscribers:VIDEO:CASSINI BEGINS ENGINE FIRING TO ENTER ORBIT VIDEO:BURN ENDS SUCCESSFULLY TO PUT CASSINI IN ORBIT VIDEO:POST-ARRIVAL NEWS CONFERENCE VIDEO:3-MINUTE PREVIEW OF CASSINI'S MISSION VIDEO:CASSINI'S ARRIVAL AT SATURN IS MAKE-OR-BREAK MOMENT VIDEO:AN INTERVIEW WITH THE CASSINI MISSION PLANNER VIDEO:AN OVERVIEW OF CASSINI'S RADIO SCIENCE Mission Preview'Flagship mission of our time' nears its destinationSeven years after launch on a four-planet gravitational bank shot covering more than 2 billion miles, NASA's $3.3 billion nuclear-powered Cassini probe - the most sophisticated robotic spacecraft ever built - has finally reached the solar system's most spectacular target: The ringed planet Saturn. This is our 8,600-word, four-part preview of the Cassini-Huygens mission: [Posted: June 12]Earlier HeadlinesCassini 'go' for Saturn orbit insertion burnExecuting stored instructions, the electronic brain of NASA's Cassini probe made final preparations for a critical 96-minute rocket firing tonight that will slow the craft by about 1,400 mph and allow Saturn's gravity to pull it into orbit. [Posted: June 30]Additional coverage for subscribers:VIDEO:WEDNESDAY'S 12 P.M. EDT CASSINI STATUS BRIEFING VIDEO:A LOOK AT INTERNATIONAL COOPERATION VIDEO:'RING-SIDE CHAT' ABOUT SPACE EXPLORATION Cassini mission hinges on tonight's engine firingAfter a seven-year voyage from Earth, NASA's $3.3 billion Cassini probe is racing toward a make-or-break rocket firing tonight, a 96-minute maneuver designed to put the craft in orbit around the ringed planet Saturn for a four-year scientific odyssey. [Posted: June 29]Additional coverage for subscribers:VIDEO:TUESDAY'S CASSINI MISSION OVERVIEW BRIEFING VIDEO:CASSINI'S ARRIVAL AT SATURN EXPLAINED VIDEO:SCIENCE OBJECTIVES FOR CASSINI ORBITER VIDEO:HUYGENS LANDER SCIENCE OBJECTIVES Saturn's rotation is a puzzleOn approach to Saturn, data obtained by the Cassini spacecraft are already posing a puzzling question: How long is the day on Saturn? Cassini took readings of the day-length indicator regarded as most reliable -- the rhythm of natural radio signals from the planet. The result was 6 minutes longer than that measured by the Voyager 1 and Voyager 2 spacecraft, which flew by Saturn in 1980 and 1981. [Posted: June 28]OTHER CASSINI HEADLINESAdditional stories today -- As NASA's Cassini-Huygens spacecraft begins its four-year orbital tour of the Saturn system, mission scientists will use an innovative imaging device to deliver the most detailed look yet at the relationship between the Sun, the giant ringed planet and the diverse collection of moons looping around it.