Huygens Team Releases First Enhanced Mosaics of Titan

HUYGENS TEAM RELEASES FIRST ENHANCED MOSAICS OF TITAN
From Lori Stiles, UA News Services, 520-621-1877
May 16, 2005

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Contact Information listed at end of news release
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Scientists on Huygens' Descent Imager Spectral Radiometer (DISR)
experiment
have generated new views of Saturn's giant moon, Titan.

The European Space Agency's Huygens probe descended onto Titan on
January
14, 2005. The University of Arizona-led DISR team released mosaics made
from
raw, unprocessed images days after Huygens landed, but they continue
processing the data.

The team now has produced the first enhanced mosaic images. They used
special image projection techniques in combining a series of images
taken as
Huygens rotated on its axis 20 kilometers, or 12.4 miles, above Titan's
surface. The images are online at the DISR website,
http://www.lpl.arizona.edu/~kholso/ and the European Space Agency
website,
http://www.esa.int/esaCP/index.html

DISR took a series of photographs of the moon's surface in sets of
three,
or triplets, as Huygens descended through Titan's atmosphere. The
images
partially overlap because the probe rotated during the descent and
because
the fields-of-view of different cameras overlapped. Scientists used
physical
features seen in more than one image to piece mosaics together like
jigsaw
puzzles.

The new mosaics are stereographic and gnomonic (pronounced
'no-mahn-ic')
projections. These are different ways of showing Titan's
three-dimensional
surface in two dimensions.

Stereo projection squeezes the entire visible surface into one image,
so it
shows size, area, distance and perspective of landscape features, said
Mike
Bushroe of the UA Lunar and Planetary Laboratory, DISR senior staff
engineer. Gnomonic projection is the kind found in maps that navigators
and
aviators use to determine the shortest distance between two points.
Gnomonic
projection makes the surface appear flat and distorts scale at the map
or
mosaic outer edges.

In the new stereographic 'fish-eye' view of Titan's surface, the
bright
area to the north (top of image) and west is higher than the rest of
the
terrain. The bright area is laced with dark lines believed to be
drainage
channels leading down to what appears to be a shoreline with river
deltas
and sand bars.

Scientists think the channels are cut by flowing liquid methane.
Precipitation run off carved the dense network of narrow channels and
features with sharp branching angles, researchers theorize. Sapping or
sub-surface flows may have created the short, stubby channels that join
at
90-degree angles, they add.

The largest run off channel starts at about the 12 o'clock position
from an
inlet on the shoreline and stretches to the left. The largest sapping
channel starts at the 9 o'clock position and continues in a straight
line up
and left. The dark wide corridor to the west just below the sapping
channel
is believed to be a major flow channel that empties into the mud flats
of
the lakebed.

The bright shapes to the northeast and east look to be ridges of ice
gravel
that are slightly higher than the flats around them. The probe is
thought to
have landed just southwest of the semi-circular shape. Researchers
can't yet
explain the light and dark areas to the south.

The gnomonic projection was made from images taken as the probe
approached
the landing site, and as surface features sharpened. North is at the
top of
the image. What appears to be a ridge of ice boulders thrusting up
through
darker lakebed material runs between lower left and upper right in this
mosaic.

The ice boulders are thought to slow the major flow from the west,
causing
the fluid to pond on the northwest side of the image and layering the
dark
material into sediment. Seeps between the boulders cut the sediment
into
channels as the fluid flows southeast.

University of Arizona Lunar and Planetary Laboratory scientist Martin
Tomasko leads the DISR team. Team members are based throughout the
United
States and Europe, with the largest contributing groups from the UA in
the
United States, from the Max Planck Institute in Germany, and the Paris
Observatory in Meudon, France.

The Cassini-Huygens mission to Saturn and Titan is a joint mission of
NASA,
the European Space Agency (ESA) and the Italian Space Agency (ASI). ESA
supplied and manages the Huygens probe that descended to Titan's
surface
Jan. 14, 2005. NASA's Jet Propulsion Laboratory, a division of the
California Institute of Technology in Pasadena, manages the mission for
NASA's Science Mission Directorate in Washington, D.C. NASA funded the
Descent Imager-Spectral Radiometer, which was built by Lockheed Martin.

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Contact Information
Mike Bushroe
UA Lunar and Planetary Laboratory
520-621-1349 mbushroe@ hindmost.lpl.arizona.edu

Bashar Rizk
UA Lunar and Planetary Laboratory
520-621-1160

Martin Tomasko, DISR leader
UA Lunar and Planetary Laboratory
520-621-6969

Jean-Pierre Lebreton
ESA Huygens Mission Manager
jplebret @ rssd.esa.int

Related Web sites
DISR - http://www.lpl.arizona.edu/~kholso/
ESA Huygens - http://www.esa.int/esaCP/index.html
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