Ua's Cassini Scientists Ready For First Close Titan Flyby
MEDIA RELATIONS OFFICE CASSINI IMAGING CENTRAL LABORATOR FOR OPERATIONS (CICLOPS) SPACE SCIENCE INSTITUTE, BOULDER, COLORADO 80301 http://ciclops.org
Heidi Finn (720) 974-5859 Cassini Imaging Central Laboratory for Operations
UA'S CASSINI SCIENTISTS READY FOR FIRST CLOSE TITAN FLYBY
The Cassini spacecraft is heading for its first close encounter with Saturn's moon Titan next Tuesday. 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 Oct. 26 flyby is the first of Cassini's 45 close Titan passes over the next four years. Scientists will combine unique types of information from a dozen instruments on the orbiter for new insights on Titan, Saturn's largest and most exotic moon. The NASA spacecraft will deploy the European Space Agency's Huygens probe to Titan in December. The probe, carrying six instruments, will descend through Titan's atmosphere in January 2005.
UA's Cassini scientists will be at the NASA's Jet Propulsion Laboratory in Pasadena, Calif., this week for this first close Titan flyby.
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Cassini imaging cameras will photograph Titan every 15 minutes or so during approach, said Alfred S. McEwen, a member of the Cassini imaging team. "We'll get a movie of Titan's very interesting clouds. They form and dissipate and blow in the wind. Some of them are strange shapes and streaks and things we really don't understand. "Then, as we get closer, we'll start mapping. We'll make a full disk, four-color mosaic. We'll see the surface, we'll see the limb hazes, we'll see whatever clouds there are," McEwen said. "These are things we'll make posters of, and that everyone will have on their walls."
"As we get closer and closer, we map specific regions at higher and higher resolution. This includes a mosaic over the Huygens landing site. It should be our best look at that location," McEwen said.
Cassini cameras will continue snapping high-resolution pictures of different Titan terrains as the spacecraft zooms on to Titan's night side.
Cassini imaging operations involve an international team of scientists headed by Carolyn Porco, UA adjunct professor of planetary sciences. Porco directs the Cassini Imaging Central Laboratory for Operations (CICLOPS) at the Space Science Institute in Boulder, Colo. Most of the uplink and downlink imaging tasks are handled at the Boulder facility.
"The Titan imaging atmosphere observations for the upcoming flyby have been planned by scientists at the Jet Propulsion Laboratory and sequenced in Boulder," Porco said. "But the very close observations, those with the goal of mapping the Titan surface at between 50 and 200 meters per pixel, have all been planned, designed and sequenced by our team members at the Lunar and Planetary Laboratory. It's a very challenging task to plan imaging sequences during a close flyby when the geometry is changing rapidly. And they've done an excellent job. We're in for quite a show."
Robert H. Brown leads Cassini's visual and infrared mapping spectrometer (VIMS) team, based at UA's Lunar and Planetary Lab in Tucson. "We know VIMS will see through the haze to Titan's surface," Brown said. "At closest approach - 1,200 kilometers (745 miles) - we'll have 600-meter-pixel resolution. We'll be able to see very small geologic features. We'll get very high resolution looks at atmospheric phenomena, too. But from my perspective, the really important thing about this encounter is really digging down below the atmosphere and getting our first real glimpse of Titan geology.
"We don't know what we're going to encounter there. I suppose you can assume we'll see common geologic forms like mountains and craters and tectonic faults, maybe even volcanism," Brown said.
Titan is possibly the land of a thousand hydrocarbon lakes. UA planetary sciences and physics Professor Jonathan I. Lunine theorized as a graduate student more than 20 years ago that Titan could have liquid hydrocarbon seas or lakes. Lunine is the only U.S. scientist selected by the European Space Agency for its three-member Huygens probe interdisciplinary science team. He and Ralph Lorenz of UA's Lunar and Planetary Laboratory also are members of the radar team. Cassini will get its first radar images of Titan on Tuesday's flyby.
"If either the radar or VIMS system on the orbiter take images of liquid-filled crater basins, that to me would be very, very exciting," Lunine said. Scientists would then have evidence that surface lakes are a source and sink for methane in Titan's hydrologic cycle.
VIMS will see Titan's hydrocarbon pools, if they exist and aren't hidden by some low-lying fog or other strange phenomenon, Brown said.
VIMS team member Caitlin Griffith said, "Closest approach will give us the most exciting VIMS data because we have that clear view down to the surface. We want to isolate different terrain types and start seeing texture."
When the Cassini spacecraft flew within 339,000 kilometers (210,600 miles) of Titan in July, VIMS was so far away that everything it saw was smeared over 150 kilometers (93 miles), Griffith said. "That's like taking a picture of Arizona but smearing all of Tucson with all of Phoenix and beyond, towards Flagstaff. This time, we'll be close enough to isolate and identify lakes and mountains, and maybe see shadows cast at different illumination angles."
Cassini won't just look at Titan next Tuesday. Cassini's Ion and Neutral Mass Spectrometer (INMS) will taste mysterious, subtle flavors in Titan's atmosphere, team member and UA planetary sciences Professor Roger Yelle said.
"Our instrument will scoop up a breath of Titan's puffy atmosphere during the flyby," Yelle said. The experiment will measure how many molecules of different masses it got in the gulp of Titan's mostly nitrogen, methane-laced atmosphere.
"Scientists with telescopes have so far seen 19 different chemical molecules in Titan's atmosphere -- more than in any other solar system body's atmosphere except Earth's," Yelle said. Laboratory experiments show there are probably many more kinds of chemicals in Titan's atmosphere, he added.
Yelle and other INMS scientists want to identify the big, complicated and interesting hydrogen-and-carbon-containing molecules because they are part of a planetary system that possibly rains methane and produces ethane ponds.
"Titan is a big laboratory where you get to play with atmospheres on planetary scales," Yelle said.
In addition, Yelle said, he is fascinated by Titan chemistry as a scientist interested in the origins of life. Learning more about how carbon-containing, or "organic," molecules form doesn't explain how DNA came to be, Yelle said. "A single strand of DNA contains about 3 billion nucleotides that if stretched out, would be something like 1.7 meters long. We're trying to understand molecules with just 10 or 12 atoms."
But Titan's hydrocarbon chemistry holds clues that explain the very first steps of how nature assembled organic molecules, which are the precursors to amino acids, the building blocks of life, he said.
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. The visual and infrared mapping spectrometer team is based at the University of Arizona Lunar and Planetary Laboratory, Tucson, Ariz.