WASHINGTON, May 29, 2012 /PRNewswire-USNewswire/ -- A NASA mission to study the moon from crust to core has completed its prime mission earlier than expected.

NASA's Cassini spacecraft made its closest approach to Saturn's tiny moon Methone as part of a trajectory that will take it on a close flyby of another of Saturn's moons, Titan.

Shortly after passing Enceladus, Cassini had a non-targeted encounter of Dione. At closest approach, the spacecraft flew within about 5,000 miles (8,000 kilometers) of the moon.

NASA's Cassini spacecraft will be flying within about 46 miles (74 kilometers) of Saturn's moon Enceladus on Wednesday, May 2, aiming primarily to learn more about the moon's internal structure.

Phoebe, one of Saturn’s 60+ moons, has been found to have planet-like properties, NASA scientists discovered while analyzing swarms of data collected and transmitted by the Cassini orbiter.