Cassini space probe will soon complete its four-year primary mission
Saturn, its rings, and its moons.
Though close to its June completion, the Cassini mission's operators
will be busy today, as the spacecraft
makes a very close flyby of one of Saturn's more interesting
interests scientists most about Enceladus is the giant geyser at its
south pole. While the moon itself is a mere 500 kilometers in
diameter, the geyser, which is composed mostly of micrometer-sized
ice particles, extends almost three times that distance into space.
The geyser makes Enceladus one of the most geologically active bodies
in our solar system.
the flyby seems daring, at one point coming as close as 50 kilometers
to the surface near the moon's equator, it will be four times that
distance when it reaches the outskirts of the plume of vapor and
particles. Though the ejected matter leaves the geyser at
approximately 400 meters per second, the small size of the particles
shouldn't pose a problem to the space probe at the speed and altitude
where it will encounter them.
team hopes to use Cassini's particle analysis equipment to get a
better understanding of what kinds of materials are spewing from the
planet's interior. While some of the particles are pure water ice,
other components include gases like carbon dioxide and methane.
Analyzing the composition will help scientists quantify and
understand any differences between the plume and the envelope of
material that surrounds the entire moon and understand how the plume
itself was formed.
today's flyby conclude successfully, other, more daring flybys may be
planned for the craft's proposed extended mission cycle to begin in
August of this year.
Jet Propulsion Laboratory has created a movie explaining and
illustrating Cassini's mission and can be found here