Cassini Double Play: Enceladus and Titan

Feature May 17, 2010

Cassini Double Play: Enceladus and Titan

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-164&cid=release_2010-164

About a month and a half after its last double flyby, NASA's Cassini spacecraft
will be turning another double play this week, visiting the geyser moon
Enceladus and the hazy moon Titan. The alignment of the moons means that
Cassini can catch glimpses of these two contrasting worlds within less than 48
hours, with no maneuver in between.

Cassini will make its closest approach to Enceladus late at night on May 17
Pacific time, which is in the early hours of May 18 UTC. The spacecraft will pass
within about 435 kilometers (270 miles) of the moon's surface.

The main scientific goal at Enceladus will be to watch the sun play peekaboo
behind the water-rich plume emanating from the moon's south polar region. Scientists using the ultraviolet imaging spectrograph will be able to use the
flickering light to measure whether there is molecular nitrogen in the plume. Ammonia has already been detected in the plume and scientists know heat can
decompose ammonia into nitrogen molecules. Determining the amount of
molecular nitrogen in the plume will give scientists clues about thermal
processing in the moon's interior.

The second of Cassini's two flybys is an encounter with Titan. The closest
approach will take place in the late evening May 19 Pacific time, which is in the
early hours of May 20 UTC. The spacecraft will fly to within 1,400 kilometers
(750 miles) of the surface.

Cassini will primarily be doing radio science during this pass to detect the subtle
variations in the gravitational tug on the spacecraft by Titan, which is 25 percent
larger in volume than the planet Mercury. Analyzing the data will help scientists
learn whether Titan has a liquid ocean under its surface and get a better picture
of its internal structure. The composite infrared spectrometer will also get its
southernmost pass for thermal data to fill out its temperature map of the smoggy
moon.

Cassini has made four previous double flybys and one more is planned in the
years ahead.

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 Science Mission Directorate in
Washington. The Cassini orbiter was designed, developed and assembled at
JPL.

More information on the Enceladus flyby, dubbed "E10," is available at:
http://saturn.jpl.nasa.gov/mission/flybys/enceladus20100518/

More information on the Titan flyby, dubbed "T68," is available at:
http://saturn.jpl.nasa.gov/mission/flybys/titan20100520/

2010-164

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

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