From: Jet Propulsion Laboratory
Posted: Friday, February 18, 2005
Cassini's third close approach to Titan on Tuesday, February 15 yielded intriguing new views of the planet-sized moon, as the spacecraft's powerful cameras looked at and through the orange murk of its thick atmosphere. Cassini sped past Titan, coming within 1,580 kilometers (982 miles) of the moon's surface. This was the spacecraft's first pass by Titan since the European Space Agency's Huygens probe parachuted to a successful landing on Jan. 14.
Images taken during the flyby, processed to enhance surface visibility and composed into a mosaic, show surface details that include improved looks at previously seen territory to the north and west of the large, bright region called Xanadu. Some of this territory has also been observed by other Cassini instruments (RADAR and VIMS) during this flyby. Scientists will be comparing their results from these different instruments in forthcoming days to get a more complete picture of the Titan surface.
Tne new image taken just prior to the flyby shows that some of the moon's surface and atmospheric features can readily be seen using Cassini's clear spectral filter, which is sensitive to a broad range of light, from ultraviolet to near-infrared. Imaging scientists normally use a narrow-band infrared filter centered at 938 nanometers, where atmospheric methane is less absorbing, to look at Titan's surface and cloud features. Images taken in the clear filter between Titan flybys are used primarily to navigate the spacecraft.
Although the clear filter is not the best way to view the surface, this finding demonstrates that with sufficient processing this filter can be used to track cloud features in inter-flyby periods and thus provide a better understanding of the evolution of Titan's atmosphere as spring approaches in the northern hemisphere.
Another of the images released today, taken after closest approach of Titan's night side, shows the thick atmosphere illuminated from behind by sunlight. In this image, a thin, detached haze layer is visible over the entire globe. The haze layer over the north polar region (at top) has a different structure, a feature that imaging scientists have noticed in earlier flybys. The outermost haze layer is very circular around the whole disk, but the structure beneath this circle is different near the north pole.
Finally, a natural color view, showing the moon's globe-enshrouding orange haze, also is included in today's image products.
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 European Space Agency built and managed the development of the Huygens probe and is in charge of the probe operations. The Italian Space Agency provided the high-gain antenna, much of the radio system and elements of several of Cassini's science instruments. The imaging team is based at the Space Science Institute, Boulder, Colo.
// end //