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Titan-Huygens_Landing_Site-00-LS27_PSS_LSoderblom_DISR_Topo20070323.jpgHuygens Probe Landing Site (perspective)53 visiteThis West-looking perspective of the Huygens Landing Site shows the Huygens descent trajectory in blue (the blue vertical lines indicate the ground track location). The base map (16 metres per pixel) is a mosaic obtained by the Descent Imager and Spectral Radiometer (DISR) on board Huygens.MareKromium
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Titan-Huygens_Landing_Site-01-PIA06435.jpgHuygens' Landing Site (true colors)54 visiteOriginal caption:"This frame is (...) a composite of Cassini imaging science sub-system images, radar images and visual and infrared mapping spectrometer images of the Huygens probe landing area.
(...) It displays the Titan surface in true color.
(...) The probe was delivered to Titan by the Cassini spacecraft, which is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif. NASA supplied two instruments on the probe: the descent imager/spectral radiometer and the gas chromatograph mass spectrometer".
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Titan-Huygens_Landing_Site-02-LS28_PSS_LASoderblom_VIMSRADAR20070323.jpgHuygens Probe Landing Site54 visiteThese images of the Huygens Landing Site on Titan were obtained by Cassini’s SAR radar (1st and 3rd rows) and VIMS (2nd and 4th rows) instruments, and are correlated in this composite view.
The 4 upper images show the Region of the Sinlap Crater in the Huygens Landing Site Region. The area shown is about 850 by 1150 Km wide.
The 4 lower images are colour-mapped as: red, to indicated solid dunes; yellow, to indicate a partial dune coverage; and green to indicate not mappable areas.MareKromium
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Titan-Huygens_Landing_Site-03-IMG002628-br500.jpgCoastline on Titan53 visiteThe deposits form when solar ultraviolet radiation and charged particles react at high altitudes with Titan’s abundant methane to produce carbon- and hydrogen-bearing (hydrocarbon) molecules like ethane and acetylene, and more complex nitrogen-bearing molecules generally called tholins. These products drift down to the surface as aerosols much in the same way smog particles on Earth form and coat surfaces. On Titan however these deposits may accumulate to thicknesses of hundreds of metres deep.
The dunes are composed of sand-sized material that agglomerated, either during its descent or when reworked by geological processes on the surface. The ice and organic landforms are as different from one another as they are spectacular. To the north of Huygens’ landing site are the bright highlands, displaying channels in a very ramified pattern, branching four or five times as they climb into the hills.
Stereoscopic images from the Descent Imager/Spectral Radiometer (DISR) camera on Huygens have now been analysed and show that some of the ridges between the channels rise to 150 - 200 metres in height, with slopes of thirty degrees. “This is extremely rugged terrain,” says Soderblom. The shape suggests that they are drainage channels, cut by liquid methane falling as rain.
MareKromium
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Titan-Huygens_Landing_Site-04-IMG002629-br500.jpgDrainage, flow and erosion on the Huygens landing site53 visiteClose - by are stubby canyons with only a few branches. They have probably been formed by ‘spring sapping’, whereby methane flows through the subsurface before emerging as a spring near the base of a hill. The spring erodes the hillside, causing it to collapse and form a cliff face.
The third area is the flat dark plain. This is mostly water ice mixed with tholin grit. “Titan’s river channels, canyons, and flood plains rival the variety seen on Earth,” says Soderblom. The dark plains show markings that suggest the region occasionally experiences flash flooding, but not from the highland drainage channels. Instead large quantities of liquid methane appear to flow from east to west.
Planetary scientists can now begin to piece together the sequence of events that led to the formation of this exotic landscape. “Huygens and Cassini have taken giant steps forward in our understanding of Titan,” says Soderblom.
MareKromium
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Titan-Huygens_Landing_Site-05-LS27_PSS_LSoderblom_DISR_Topo20070323.jpgTectonic and fluid-flow patterns on Titan (HR)53 visiteThis image of Titan’s surface, obtained by Huygens’ DISR imager, shows patterns of tectonic and fluid-flow activity.
The tectonic patterns are indicated by blue lines; the drainage divide is indicated by the red line; flow directions are indicated by the green arrows.
The Huygens Landing Site is marked by a white cross.
MareKromium
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Titan-Huygens_Landing_Site-06.jpgThe "Landing Site": a new best estimate53 visiteCaption NASA originale:"A view of Titan from the visual and infrared mapping spectrometer 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 Descent Imager/Spectral Radiometer (DISR) instrument from an altitude of 20 Km (about 12 miles)".
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Titan-Huygens_Landing_Site-07-PIA03569.jpgHuygens' Landing Site?53 visiteOriginal caption:"On the left, in color, is a composite of the Imaging Camera and Infrared Data (red areas are brighter and blue darker, as seen in infrared). On the right is the Synthetic Aperture Radar Image. The Huygens descent images are shown inset on the left image and outlined in yellow on the right. The magenta cross in both images shows the best estimate of the actual Huygens Landing Site. This is a preliminary result, based on the best information available at the present time. In the left image, the brighter areas seen by the Huygens camera correspond to the large area depicted in red and yellow. On closer inspection, bright features within the Huygens mosaic seem to correspond to smaller features in the map composed of data from the VIS and Imaging Camera. On the right, the correspondence is less clear. In radar images bright features are usually rougher, so one would not necessarily expect an obvious connection".
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Titan-Huygens_Landing_Site-08-PIA06136_modest.jpgHuygens' probe landing site53 visiteCaption originale NASA (dal "Planetary Photojournal"):"Shown here are two images of the expected landing site of Cassini's Huygen's probe (latitude 10.6 S, longitude 191 W). At right is a wide-angle image showing most of Titan's disc, with a scale of 10 Km (6.2 miles) per pixel. At left is a narrow-angle image of the landing site at a scale of 0.83 Km (0.5 miles) per pixel (location shown by black box at right). North is tilted about 45 degrees from the top of both images. The surface has bright and dark markings with a streamlined pattern consistent with motion from a fluid, such as the atmosphere, moving from west to east (upper left to lower right). The image at left is 400 Km (249 miles) wide. Both images were taken by Cassini's imaging science subsystem through near-infrared filters".
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Titan-Huygens_Landing_Site-09-PIA06172_modest.jpgHuygens' descent map (1)53 visiteCaption NASA originale:"This map illustrates the planned imaging coverage for the Descent Imager/Spectral Radiometer (DISR), onboard the Huygens probe during the probe's descent toward Titan's surface on Jan. 14, 2005. The DISR is one of two NASA instruments on the probe. The colored lines delineate regions that will be imaged at different resolutions as the probe descends. On each map, the site where Huygens is predicted to land is marked with a yellow dot. This area is in a boundary between dark and bright regions. This map was made from the images taken by the Cassini spacecraft cameras on Oct. 26, 2004, at image scales of 4 to 6 Km per pixel. The images were obtained using a narrow band filter centered at 938 nanometers - a near-infrared wavelength (invisible to the human eye) at which light can penetrate Titan's atmosphere to reach the surface and return through the atmosphere to be detected by the camera. The images have been processed to enhance surface details".
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Titan-Huygens_Landing_Site-10-PIA06173_modest.jpgHuygens' descent map (2)53 visiteCaption NASA originale:"For about two hours, the probe will fall by parachute from an altitude of 160 Km (99 miles) to Titan's surface. During the descent the DISR and a few other science instruments will send data about the moon's atmosphere and surface back to the Cassini spacecraft for relay to Earth. The DISR will take pictures as the probe slowly spins and some of these will be made into panoramic views of Titan's surface.
The first map (PIA-06172) shows expected coverage by the Descent Imager/Spectral Radiometer side-looking imager and two downward-looking imagers - one providing medium-resolution and the other high-resolution coverage. The planned coverage by the medium- and high-resolution imagers is the subject of this map (PIA-06173)".
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Titan-Huygens_Landing_Site-11-PIA07229_modest.jpgHuygens' descent map (3) 56 visiteThe octagons indicate anticipated fields of view of panoramic mosaics of images taken by Huygens' descent imager and spectral radiometer instrument as the probe reaches certain altitudes during its descent. This map shows the footprints for mosaics to be assembled from 36 individual images at each altitude, with the field of view cut off at 75° from straight down although the actual images will extend all the way to the hazy horizon. Each mosaic made this way will be about 1.300 by 1.300 pixels. The largest octagon (in red) is about 1.120 Km across and represents the field of view for the mosaic of images taken at an altitude of 150 Km. From that height, individual pixels in the center of the image will be about 150 mts across, though haze between the ground and the camera at that height will likely degrade the resolution in those images. The location of the anticipated landing site is based on modeling of Titan's winds, and the actual landing site will be different if the actual winds experienced by Huygens during descent differ from this model.
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