Last night at some ungodly AM hour on the east coast (slightly less ungodly on the left coast, equally ungodly in Europe), the Cassini-Huygens probe fired its rockets and put itself into orbit around Saturn.
The Cassini-Huygens probe has traveled nearly 3.5 billion km (2.2 billion miles to us USians) since its October 15th, 1997 launch from Florida. The probe is the first spacecraft to orbit the ringed gas giant.
Cassini carries 12 instruments that will study the planet, rings and moons in extensive detail. Riding aboard Cassini is a second spacecraft, the Huygens probe, built by the European Space Agency. It carries half a dozen instruments that will study Titan, Saturn’s largest moon, a prime target for both Cassini and the Huygens probe. Titan is the only moon in the solar system to have a dense atmosphere and resembles the early Earth in deep freeze.
After seven years in space, Cassini went into orbit around Saturn on July 1, 2004. Since then, have have used our Langmuir probe instrument onboard for investigating the space physics of the Saturn system, including its rings and moons, particularly Titan and Enceladus. The Langmuir probe is designed and built by us at the Swedish Institute of Space Physics in Uppsala, and we get a lot of nice data and results.
Lots of information is available at the Cassini-Huygens site.

Nice when does the Cassini-Huygens probe comeback?