Cassini-Huygens.

The Cassini spacecraft was launched on October 15th, 1997 from Cape Canaveral, located in Florida. Cassini is considered one of the most complex interstellar spacecrafts ever built. There have only ever been 2 other spacecrafts that were heavier than Cassini, and they were sent to Mars by the former Soviet Union. It is 6.7 meters high and 4 meters wide, with a weight of 5,560 lb. This spacecraft is made up of 2 elements: The Huygens probe, and the Cassini orbiter. The structure of this spacecraft, and the powerful cameras it carries, helps send back to Earth accurate measurements, and detailed images.

Here is a list of Cassini's primary objectives. This information is from a website that will be posted at the bottom of this article.

1. Determine the three-dimensional structure and dynamic behavior of the rings of Saturn
2. Determine the composition of the satellite surfaces and the geological history of each object
3. Determine the nature and origin of the dark material on Iapetus's leading hemisphere
4. Measure the three-dimensional structure and dynamic behavior of the magnetosphere
5. Study the dynamic behavior of Saturn's atmosphere at cloud level
6. Study the time variability of Titan's clouds and hazes.
7. Characterize Titan's surface on a regional scale.

http://en.wikipedia.org/wiki/Cassini%E2%80%93Huygens