Cassini–Huygens

Cassini–Huygens is an unmanned spacecraft sent to the planet Saturn. It is a flagship-class NASA–ESA–ASI robotic spacecraft. Cassini is the fourth space probe to visit Saturn and the first to enter orbit, and its mission is ongoing as of 2016. It has studied the planet and its many natural satellites since arriving there in 2004.

Development started in the 1980s. Its design includes a Saturn orbiter, and a lander for the moon Titan. The lander, called Huygens, landed on Titan in 2005. The two-part spacecraft is named after astronomers Giovanni Cassini and Christiaan Huygens.

The spacecraft launched on October 15, 1997 aboard a Titan IVB/Centaur and entered orbit around Saturn on July 1, 2004, after an interplanetary voyage that included flybys of Earth, Venus, and Jupiter. On December 25, 2004, Huygens separated from the orbiter and reached Saturn's moon Titan on January 14, 2005. It entered Titan's atmosphere and descended to the surface. It successfully returned data to Earth, using the orbiter as a relay. This was the first landing ever accomplished in the outer Solar System.