The Cassini probe is really a plot to "stellate" Saturn. The Free Masons and other Illuminati in on the plot will use Cassini's plutonium fuel to trigger a fission explosion. This, in turn, will create a fusion reaction that will ignite Saturn into a small sun.
the motivation appears to be terraforming Saturn's moons, particularly Titan. I expect that is where the Illuminati intend to flee when Earth's resources are used up.