TheCassinispacecraftwassentonitswaytoSaturnin1997.Sincethen,shehastravellednearlyfourbillionkilometers,deliveredaprobetoatoxicmoon,discoveredphantasmagoricalstructuresontheplanet'sicyrings,studiedthestartlingatmosphereonatinymoon.Now,onadaringspiralorbit,CassiniwillstreaktowardSaturnitself,streamingdatatoEarthbeforebe..aaa