NASA’s Cassini spacecraft successfully switched to a backup set of propulsion thrusters late Wednesday, which will allow the long-lived machine to continue scoping out Saturn and its moons.
The swap was performed because of degradation in the performance of the primary thrusters, which had been in use since Cassini’s launch in 1997. This is only the second time in Cassini’s 11 years of flight that the engineering teams have gone to a backup system.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. Since its launch four years ago, the mission sent the Huygens probe to Saturn’s largest moon, Titan, and has yielded copious data about Saturn, its rings and its many moons.
The thrusters are used for making small corrections to the spacecraft’s course, for some attitude control functions, and for making angular momentum adjustments in the reaction wheels, which also are used for attitude control. The redundant set is an identical set of eight thrusters. Almost all Cassini engineering subsystems have redundant backup capability.
Cassini has successfully completed its original four-year planned tour of Saturn and is now in extended mission operations.