Two years of hard work by NASA orbital engineers have allowed the team behind the Cassini mission to add another seven years to the probe’s already astonishing career. Six years into the mission and with only 22% of it’s fuel remaining, a new mission has been drawn up allowing it to continue exploring Saturn and it’s systems of rings and planets. To achieve such longevity with so little fuel requires some very careful navigation, eking the maximum advantage from gravitational assists to move the probe between the various orbits required for each sub-mission. The calculations and simulations required to plan this route took two full years to complete and fine tune. The end result should be a bonanza of new images and data, as the probe has already returned some of the most beautiful and surprising views from Saturn, and the following seven years can’t fail to be just as productive.
Refer the original New York Times article for a very complete write-up on the history and future of the Cassini Mission