Cassini–Huygens retirement

The planned end of mission for Cassini is disposal by a controlled fall into Saturn's atmosphere on September 15, 2017. This method was chosen because it is imperative to ensure protection and prevent biological contamination of any of the moons of Saturn now thought to offer potentially habitable environments.

However, this plan was chosen prior to future planetary flagship missions being put on hold indefinitely in 2013. Factors that can affect the mission end method are the amount of rocket fuel it has left, the health of the spacecraft, and funding for operations on Earth.

Some possibilities for Cassini's later stages were aerobraking into orbit around Titan, leaving the Saturn system, or making close approaches and/or changing its orbit. For example, it could collect solar wind data in a heliocentric orbit.

During planning for its extended missions, various future plans for Cassini were evaluated on the basis of science return, cost, and time. Some of the options examined include collision with Saturn atmosphere, an icy satellite, or rings; another was departure from Saturn orbit to Jupiter, Uranus, Neptune, or a centaur. Other options included leaving it in certain stable orbits around Saturn, or departure to a heliocentric orbit. Each plan requires certain amounts of time and changes in velocity. Another possibility was aerobraking into orbit around Titan.

This table is based on page 19 of Cassini Extended Missions (NASA), from 2008.

On July 4, 2014, the Cassini science team announced that the proximal orbits of the probe would be named the "Cassini Grand Finale". This would be immediately preceded by a gradual shift in inclination to better view Saturn's polar hexagon, and a very close flyby of Enceladus to more closely study its cryovolcanism.

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