The spacecraft - which was launched from Florida in 1997 - has used up almost all of its rocket propellant and so operators will deliberately plunge it through Saturn's atmosphere to ensure the planet's moons remain pristine for future exploration.
NASA's website states: "On Sept. 15, 2017, the spacecraft will make its final approach to the giant planet Saturn. But this encounter will be like no other.
"This time, Cassini will dive into the planet's atmosphere, sending science data for as long as its small thrusters can keep the spacecraft's antenna pointed at Earth. Soon after, Cassini will burn up and disintegrate like a meteor."
Though the craft only has a few days left until it burns up, scientists are determined to extract every piece of data they can until then.
Scientist Michelle Dougherty told BBC Radio 4's 'Inside Science': "We're now running on fumes.
"The fact that we've got as far as we have, so close to the end of mission, is spectacular. We're almost there and it's going to be really sad watching it happen."
The mission has cost $3.9 billion but has broken huge amounts of new ground by providing data about Saturn, its moons and rings, and the possibility of life beyond Earth.
And scientists totally re-evaluated their approach to space exploration after Cassini found one of Saturn's moons, Enceladus, contains many ingredients needed for life.
By the end of its mission, Cassini will have travelled more than two billion miles through space and observed nearly half of a Saturn year.
It reached Saturn in 2004 after a seven-year journey through the solar system and had its initial mission extended twice.
Thomas Zurbuchen, associate administrator for NASA's science mission directorate, said: "Cassini has transformed our thinking in so many ways.
"Congratulations to the entire Cassini team."