Titan, by the Huygens Probe, which was part of the Cassini-Huygens Probe.

Cassini-Huygens. The actual probe is called Huygens. See the Related Links below.

Yes. In 2004 the Cassini-Huygens probe reached Saturn, and early in 2005 the Huygens probe landed on the surface of Titan.

Huygens Probe

The Cassini-Huygens probe. cassini mapped and analyzed the atmosphere of Jupiter while the huygens probe was dropped deep into the atmosphere to record and take pictures of the atmospheric conditons. The two were named after famous astronomers and scientests; their last names obviously being cassini and huygens