NASA in partnership with European Space Agency (ESA) and Italian Space Agency (Agenzia Spaziale Italiana or ASI) on 15th October, 1997 from Cape Canaveral Air Force Station, Florida on launch vehicle Titan IVB/ Centaur launched Cassini which entered orbit around Saturn on 1st July 2004. The main aim of this mission was to collect information about the planet's internal structure and the origins of the rings, obtain the first-ever sampling of Saturn's atmosphere and particles coming from the main rings, and capture the closest-ever views of Saturn's clouds and inner rings.
Cassini was an unmanned spacecraft sent to the planet Saturn. It was the 4th space probe to visit Saturn but the 1stone to enter successfully in its orbit.Its design included a Saturn orbiter (Cassini) and a lander (Huygens) for the moon Titan. They were named after astronomers Giovanni Cassini and Christiaan Huygens.Giovanni Domenico Cassini didn’t discover Saturn and it was actually Galileo who first saw the planet’s rings. However, Cassini was the first to notice that there are divisions in Saturn’s rings. On 25th December 2004, Huygens lander had separated from orbiter and landed on Saturn’s moon Titan on 14 January 2005. This was the first landing ever accomplished in the outer Solar System.
During its time at Saturn, Cassini made various discoveries, including a global ocean that showed indications of hydrothermal activity within the icy moon Enceladus which are chemical reactions like the hot fissures in the Earth’s ocean. On Earth, hydrothermal vents have microbial life, it is expected that Enceladus and other “ocean worlds” could be habitable.It has also been found that the moon Enceladus has a global ocean under its surface. The moon is just 314 miles (505 km) across, meaning that it’s small enough to fit inside the length of the U.K.Another important discovery was that of presence of liquid methane seas on its moon Titan. Since arriving in the Saturn system in 2004, the Cassini spacecraft has revealed that more than 620,000 square miles (1.6 million square kilometers) of Titan's surface -- almost two percent of the total -- are covered in liquid.
By 2017, Cassini had spent 13 years in orbit around Saturn, following a seven-year journey from Earth. The spacecraft was running low on the rocket fuel used for adjusting its course. If it would have been left unchecked, it would have eventually prevented mission operators from controlling the course of the spacecraft.
It was because of the Cassini data which revealed two moons of Saturn, Enceladus and Titan may have the potential to contain habitable – or at least "prebiotic” – environments. NASA on 4th April, 2017 announced that Cassini would be taking its “Grand Finale” dive towards Saturn.In order to avoid the unlikely possibility of Cassini someday colliding with one of these moons.
On 26th April, 2017, that dive began when the spacecraft dropped in the middle of the largest gap in Saturn’s rings. It plunged into Saturn's atmosphere on 15th September, 2017. The spacecraft made the closest-ever observations of the planet. The spacecraft made detailed maps of Saturn's gravity and magnetic fields, revealing how the planet is arranged internally which would possibly help in solving the mystery of how fast Saturn is rotating.Cassini's particle detectors sampled icy ring particles being funneled into the atmosphere by Saturn's magnetic field.Its cameras took amazing, ultra-close images of Saturn's rings and clouds.