UA's Cassini Scientists Ready for First Close Titan Flyby

UA's CASSINI SCIENTISTS READY FOR FIRST CLOSE TITAN FLYBY
From Lori Stiles, UA News Services, 520-621-1877
October 25, 2004

The Cassini spacecraft is heading for its first close encounter with
Saturn's moon Titan tomorrow. 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 NASA's Jet Propulsion Laboratory in
Pasadena, Calif., this week for this first close Titan flyby.
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Science Contact Information -
UA Cassini science contacts listed at end of release

UA Media Contact
Lori Stiles 520-621-1877

CICLOPS Media Contact
Heidi Finn, 720-974-5859

Related Web sites

Cassini-Huygens mission - http://saturn.jpl.nasa.gov
and http://www.nasa.gov/cassini

Cassini imaging team home page - http://ciclops.org
(Updated images are available on this website)

Cassini VIMS team home page - http://wwwvims.lpl.arizona.edu

UA Lunar & Planetary Laboratory - http://www.lpl.arizona.edu

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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
tomorrow'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.

# # #

UA SCIENCE CONTACTS ON CASSINI/HUYGENS - Scientists from UA's Lunar and
Planetary Laboratory (LPL) who work on the Cassini/Huygens mission include:

* Jonathan Lunine, 520-621-2789, e-mail to
UA professor of theoretical planetary science and physics, Lunine is an
interdisciplinary scientist on the Cassini mission specializing in Titan�s
surface and atmosphere. He is also a member of both the Radar and the Gas
Chromatograph-Mass Spectrometer (GCMS) teams. Lunine began planning the
Cassini mission as a graduate student. He titled his feature article on the
mission, published in the June 2004 Scientific American, "Saturn at Last!"
Lunine is one of the most widely interviewed Cassini scientists when the
subject is Titan, Saturn's largest moon. Titan, Lunine says, is "our best
chance to study organic chemistry in a planetary environment that has
remained lifeless over billions of years. With a thick, nitrogen-rich
atmosphere and possibly hydrocarbon seas, Titan may harbor organic compounds
important in the chain of chemistry that led to life on Earth."

* Robert H. Brown, 520-626-9045, e-mail to
Professor Brown is the leader of the Cassini Visual and Infrared Mapping
Spectrometer (VIMS) Science team. The $60 million imaging spectrometer takes
pictures in 352 separate colors simultaneously, with wavelengths between 300
and 5100 microns, covering the visible and extending into the infrared. VIMS
will identify the chemical make-up and propeties of Saturn's moons. This
team determined from the June 11 flyby that Saturn's moon Phoebe came from
the outer solar system beyond Neptune. Rick McCloskey (520-626-3255) built
VIMS' ground data system, which is the system that controls the experiment
and stores all its data. Others on the VIMS grounds operations team
headquartered at the Lunar & Planetary Lab are Dan Moynihan, Dyer Lytle and
John Ivens. VIMS home page: http://wwwvims.lpl.arizona.edu/

* Caitlin Griffith, 520-626-3806, e-mail to
Griffith is a team member on the Visual and Infrared Mapping Spectrometer
(VIMS) experiment on the Cassini orbiter, which will image Titan's little
known lower atmosphere and surface, and measure the surface composition,
cloud morphology and methane humidity. Griffith and her colleagues
discovered the presence of methane clouds in Titan's atmosphere, which
indicates that Titan has a methane cycle like the hydrologic cycle on Earth,
with clouds, rain and seas. Griffith's work also indicates that water ice is
exposed on Titan's surface, despite the likely existence of organic
sediments and possible methane oceans.

* Ralph Lorenz, 520-621-5585, e-mail to
Lorenz is a member of both the Cassini spacecraft's radar mapping team and a
co-investigator of the Surface Science Package on the Huygens probe. One of
Lorenz' major goals is to map Titan's landscape. He began working on the
Huygens project as an engineer for the European Space Agency in 1990, and
then earned his doctorate from the University of Kent at Canterbury,
England, while building one of the probe's experiments. He joined the
University of Arizona in 1994 where he started work on Cassini's Radar
investigation. He is a co-author of the book, "Lifting Titan's Veil"
published in 2002 by Cambridge University Press.

* Alfred McEwen, 520-621-4573, e-mail to
McEwen is member of Cassini's Imaging Science Subsystem (ISS) team and is a
planetary geologist and director of the Planetary Image Research Laboratory
(PIRL). He also was a member of the imaging science teams of the Galileo
mission to Jupiter and is a participating scientist on Mars Global Surveyor
(MGS) and Mars Odyssey. He is principal investigator for the High Resolution
Imaging Science Experiment (HiRISE) for Mars Reconnaissance Orbiter (MRO) to
launch in 2005. For Galileo, McEwen led the sequence planning and science
analysis for Jupiter's volcanically active moon Io. For Cassini, he is
leading the planning for imaging observations of Saturn's giant satellite
Titan. In his cover story, "Journey to Saturn," for the Jan. 2004 issue of
Astronomy magazine, McEwen identified 10 top mission highlights. Elizabeth
Turtle, Doug Dawson, undergraduate student Jason Perry and graduate student
Stephanie Campbell work with McEwen in planning the Titan observations.

* Elizabeth Turtle, 520-621-8284, e-mail to
Turtle is part of McEwen's group that planned and will analyze Cassini�s
imaging observations of Titan�s surface. She will use the Cassini images to
map Titan�s surface and study its landforms. It parallels her work on the
Galileo mission to Jupiter, where she mapped and studied landforms,
particularly for the moons Io and Europa.

* Roger Yelle, 520-621-6243, e-mail to
Yelle is a team member on the Ion and Neutral Mass Spectrometer (INMS)
experiment on the Cassini mission. It will analyze the composition of
Titan�s atmosphere down to the parts per million level. Yelle and his
colleagues, including collaborators from the Imperial College London and
Boston University, are developing a comprehensive model for the chemistry,
energetics and dynamics of Titan's upper atmosphere.

* Martin Tomasko, 520-621-6969, email to
Tomasko, research professor in planetary atmospheres and radiative transfer,
is the principal investigator on the Descent Imager Spectral Radiometer
(DISR) on the European Space Agency's Huygens probe. The DISR is the optical
package in the probe, which will separate from the orbiter Dec. 24 and
cruise down through Titan's atmosphere mid-January 2005. As the probe
descends toward Titan�s surface, DISR will be take pictures of Titan�s
atmosphere and surface using three camera lenses pointed at three different
angles. One camera looks straight down, one camera points at an angle of
almost 45 degrees, and one camera looks almost straight out horizontally.
Tomasko and other scientists will create 20 panoramic mosaics from their
Titan images. As the probe gets closer to the ground, it will take too long
for the cameras to take panoramic pictures, so they�ll begin transmitting
individual images.

* Bashar Rizk, 520- 621-1160, e-mail to .
Rizk is a co-investigator on the DISR instrument. His responsibilities
include fitting the 750 or so images the instrument will acquire into a
global context in order to derive the Huygens probe�s ground track, its
attitude history, its descent trajectory and the horizontal and vertical
winds blowing on its journey to Titan�s surface. Trying to display the
downward-looking and very wide-angle field of view of the DISR imagers when
fully mosaicked is challenging: The lower hemisphere below the probe from
one horizon to nadir to the opposite horizon has led to the routine
development and use of several different projections in order to lay what is
basically a spherical surface onto a flat piece of paper. Rizk and other
team members will develop perspective animation from their imaging to convey
look and feel of this alien world. Rizk is also refining a spherical model
of Titan�s radiative transfer, including polarization, which will be used to
refine the knowledge of Titan�s aerosols and radiative energy balance when
used with other DISR data returned from the Huygens probe.

* Peter Smith, 520-621-2725, e-mail to
Smith, an LPL senior research scientist, is a co-investigator on the DISR
instrument. He has been involved with the team since 1989 when he helped
write the proposal for the building and design of the instrument. He became
project manager during the first 4 years of the project monitoring progress
at Lockheed Martin Astronautics. Smith has done notable research on Titan,
and will be working with surface data sent back from the Huygens probe,
comparing it to observations of the surface obtained by the Hubble Space
Telescope. He will also analyze the distribution and type of aerosol
particles found in Titan�s atmosphere. Smith is principal investigator for
the $355 million, 2007-2008 Phoenix lander mission to Mars. This NASA Scout
mission is the first Mars mission run by a university.

* Lyn Doose, 520-621-2127, e-mail to
Doose is a co-investigator on the Descent Imager Spectral Radiometer (DISR)
on the Huygens probe. He will study radiative transfer in Titan�s
atmosphere, looking at where clouds and haze are found in the atmosphere. He
also will interpret data to find the heat budget of Titan (looking at how
much solar energy is absorbed, and where on Titan it is absorbed), and study
the abundance and absorption properties of gases in Titan�s atmosphere.

* Donald M. Hunten, 520-621-4002, e-mail to
Hunten, Regents' Professor in Earth and planetary atmospheres, is a
co-investigator on the gas chomatograph-mass spectrometer (GCMS) on the
Huygens probe. The GCMS will measure the atmosphere composition of Titan as
the probe descends, and, with luck, after the probe lands. Hunten and other
scientists are interested in learning what elements are present in Titan�s
thick atmosphere.

* Gabriel Tobie, 520-626-0093, e-mail to
Tobie is a visiting scholar who has done previous modeling of Titan�s
surface and interior. He will use data sent back from the Cassini mission to
learn more about the evolution of Titan, the surface cryovolcanic activity
and the methane cycle.