[meteorite-list] Cassini Provides New Views of Titan, Saturn's Largest Moon

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Sat Jul 3 16:18:35 2004
Message-ID: <200407032018.NAA01805_at_zagami.jpl.nasa.gov>

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA 91109. TELEPHONE (818) 354-5011
http://www.jpl.naas.gov

Carolina Martinez (818) 354-5011
Jet Propulsion Laboratory, Pasadena, Calif.

Donald Savage (202) 358-1727
NASA Headquarters, Washington

NEWS RELEASE: 2004-171 July 3, 2004

CASSINI PROVIDES NEW VIEWS OF TITAN, SATURN'S LARGEST MOON

The Cassini spacecraft has revealed surface details of
Saturn's moon Titan and imaged a huge cloud of gas
surrounding the planet-sized moon.

Cassini gathered data before and during a distant flyby of
 the orange moon yesterday. Titan's dense atmosphere is
opaque at most wavelengths, but the spacecraft captured
some surface details, including a possible crater, through
wavelengths in which the atmosphere is clear.

"Although the initial images appear bland and hard to
interpret, we're happy to report that, with a combination
of instruments, we have indeed seen Titan's surface with
unprecedented clarity. We also look forward to future, much
closer flybys and use of radar for much greater levels of
surface detail," said Dr. Dennis Matson of NASA's Jet
Propulsion Laboratory, Pasadena, Calif., project scientist
for the international Cassini-Huygens mission.

Cassini's visible and infrared mapping spectrometer pierced
the smog that enshrouds Titan. This instrument, capable of
mapping mineral and chemical features of the moon, reveals
an exotic surface bearing a variety of materials in the
south and a circular feature that may be a crater in the
north. Near-infrared colors, some three times redder than
the human eye can see, reveal the surface with unusual clarity.

"At some wavelengths, we see dark regions of relatively pure
water ice and brighter regions with a much higher amount of
non-ice materials, such as simple hydrocarbons. This is
different from what we expected. It's preliminary, but it may
change the way we interpret light and dark areas on Titan,"
said JPL's Dr. Kevin Baines, Cassini science-team member. "A
methane cloud is visible near the south pole. It's made of
unusually large particles compared to the typical haze
particles surrounding the moon, suggesting a dynamically
active atmosphere there."

This is the first time scientists are able to map the
mineralogy of Titan. Using hundreds of wavelengths, many of
which have never been used in Titan imaging before, they are
creating a global map showing distributions of
hydrocarbon-rich regions and areas of icy material.

Cassini's camera also sees through the haze in some
wavelengths. "We're seeing a totally alien surface," said Dr.
Elizabeth Turtle of the University of Arizona, Tucson. "There
are linear features, circular features, curvilinear features.
These suggest geologic activity on Titan, but we really don't
know how to interpret them yet. We've got some exciting work cut
out for us."

Since entering orbit, Cassini has also provided the first view
of a vast swarm of hydrogen molecules surrounding Titan well
beyond the top of Titan's atmosphere. Cassini's magnetospheric
imaging instrument, first of its kind on any interplanetary
mission, provided images of the huge cloud sweeping along with
Titan in orbit around Saturn. The cloud is so big that Saturn
and its rings would fit within it. "The top of Titan's
atmosphere is being bombarded by highly energetic particles in
Saturn's radiation belts, and that is knocking away this
neutral gas," said Dr. Stamatios Krimigis of Johns Hopkins
Applied Physics Laboratory, Laurel, Md., principal investigator
for the magnetospheric imager. "In effect, Titan is gradually
losing material from the top of its atmosphere, and that
material is being dragged around Saturn."

The study of Titan, Saturn's largest moon, is one of the major
goals of the Cassini-Huygens mission. Titan may preserve in
deep-freeze many chemical compounds that preceded life on Earth.
Friday's flyby at a closest distance of 339,000 kilometers
(210,600 miles) provided Cassini's best look at Titan so far,
but over the next four years, the orbiter will execute 45 Titan
flybys as close as approximately 950 kilometers (590 miles).
This will permit high-resolution mapping of the moon's surface
with an imaging radar instrument, which can see through the
opaque haze of Titan's upper atmosphere. In January 2005, the
Huygens probe that is now attached to Cassini will descend
through Titan's atmosphere to the surface.

During the ring plane crossing, the radio and plasma wave
science instrument on Cassini measured little puffs of plasma
produced by dust impacts. While crossing the plane of Saturn's
rings, the instrument detected up to 680 dust hits per second.
"The particles are comparable in size to particles in cigarette
smoke," said Dr. Don Gurnett of the University of Iowa, Iowa City,
principal investigator for the instrument. "When we crossed the
ring plane, we had roughly 100,000 total dust hits to the
spacecraft in less than five minutes. We converted these into
audible sounds that resemble hail hitting a tin roof."

The spacecraft reported no unusual activity due to the hits and
performed flawlessly, successfully going into orbit around
Saturn on June 30. The engine burn for entering orbit went so
well that mission managers have decided to forgo an
orbital-adjustment maneuver scheduled for today.

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. JPL designed,
developed and assembled the Cassini orbiter.

For the latest images and more information about the
Cassini-Huygens mission, visit

http://saturn.jpl.nasa.gov and

http://www.nasa.gov/cassini .

-end-
Received on Sat 03 Jul 2004 04:18:32 PM PDT