Aiming for Safe Harbor

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Titan’s landing region. Image Credit: NASA/JPL

This map illustrates the planned imaging coverage for the Descent Imager/Spectral Radiometer, onboard the European Space Agency’s Huygens probe during the probe’s descent toward Titan’s surface on Jan. 14, 2005. The Descent Imager/Spectral Radiometer 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 kilometers (2.5 to 3.7 miles) 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. Only brightness variations on Titan’s surface are seen; the illumination is such that there is no shading due to topographic variations.

For about two hours, the probe will fall by parachute from an altitude of 160 kilometers (99 miles) to Titan’s surface.

During the descent the camera on the probe and five other science instruments will send data about the moon’s atmosphere and surface back to the Cassini spacecraft for relay to Earth.

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Radar image of flowing, contrasting geography. Image Credit: NASA/JPL

The Descent Imager/Spectral Radiometer will take pictures as the probe slowly spins, and some these will be made into panoramic views of Titan’s surface.

Getting a closer look at Titan’s surface this week has long been a goal for planetary exploration. As Ralph Lorenz from the University of Arizona’s Lunar and Planetary Lab, described: "It’s interesting from an astrobiological point of view in particular. The photochemistry in Titan’s atmosphere produces lots of organic compounds, and about 20 compounds have been identified already. But it’s an evolutionary dead-end. Titan’s atmosphere is so cold, there’s very little oxygen or oxygen-bearing compounds in there. All the compounds that have been detected are hydrocarbons – compounds containing carbon and hydrogen – or nitriles – compounds with carbon, hydrogen, and nitrogen. But if this stuff rains out onto the surface, and it interacts with liquid water at any stage, you very quickly form a lot of oxygen-bearing compounds like amino acids. This has been done in the laboratory, and it only takes a few hours. "


Related Web Pages

Cassini
Saturn Edition, Astrobiology Magaz.
Saturn’s Rings in UV
Cassini Closes In on Saturn

Saturn– JPL Cassini Main Page
Lord of the Rings
Space Science Institute, Imaging Team Boulder, Colorado
Saturn: The Closest Pass
Prebiotic Laboratory
Planet Wannabe
Where is Cassini Now?