[meteorite-list] Cassini Successfully Flies over Enceladus

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 16 Apr 2012 11:12:04 -0700 (PDT)
Message-ID: <201204161812.q3GIC4Md027525_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2012-106

Cassini Successfully Flies over Enceladus
Jet Propulsion Laboratory
April 16, 2012

These raw, unprocessed images of Saturn's moons Enceladus and Tethys
were taken on April 14, 2012, by NASA's Cassini spacecraft.

Cassini flew by Enceladus at an altitude of about 46 miles (74
kilometers). This flyby was designed primarily for the ion and neutral
mass spectrometer to analyze, or "taste," the composition of the moon's
south polar plume as the spacecraft flew through it. Cassini's path
took it along the length of Baghdad Sulcus, one of Enceladus' "tiger
stripe" fractures from which jets of water ice, water vapor and organic
compounds spray into space. At this time, Baghdad Sulcus is in darkness,
but that was not an obstacle for another instrument, the composite
infrared spectrometer, which can see features by their surface
temperatures and which also took measurements during this flyby.

As soon as daylight passed into the spacecraft's remote sensing
instruments' line of sight, Cassini's cameras acquired images of the
surface. The wide-angle-camera image included in the new batch, taken
from around the time of closest approach, has some smearing from the
movement of the spacecraft during the exposure, but still shows the
surface in vivid detail.

Cassini's cameras also imaged Enceladus' south polar plume at a high
phase angle as the satellite appeared as a thin crescent and the plume
was backlit.

After the Enceladus encounter, Cassini passed the moon Tethys with a
closest approach distance of about 5,700 miles (9,100 kilometers). This
was Cassini's best imaging encounter with Tethys since a targeted
encounter in September 2005. The 2005 encounter, with a closest approach
distance of about 930 miles (1,500 kilometers), provided the images of
Tethys with the best resolution and captured views of the side of Tethys
that faces Saturn in its orbit. This new encounter examined the opposite
side of Tethys, providing some of the highest-resolution images of the
side that faces away from Saturn. Cassini acquired a 22-frame mosaic of
this side, which features the large impact basin named Odysseus.
Scientists will use these new data in conjunction with images from
previous encounters to create digital elevation maps of the moon's surface.

The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. NASA's Jet
Propulsion Laboratory in Pasadena manages the mission for the agency's
Science Mission Directorate in Washington. The Cassini orbiter and its
two onboard cameras were designed, developed and assembled at JPL. The
imaging operations team is based at the Space Science Institute in
Boulder, Colo. JPL is a division of Caltech.

For more information about the Cassini-Huygens mission, visit
http://saturn.jpl.nasa.gov <http://saturn.jpl.nasa.gov/> and
http://www.nasa.gov/cassini .

Jia-Rui C. Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jia-rui.c.cook at jpl.nasa.gov

2012-106
Received on Mon 16 Apr 2012 02:12:04 PM PDT