A probe once landed on Saturn's moon Titan, nearly a billion miles from home

In January 2005, the European Space Agency's Huygens probe separated from NASA's Cassini spacecraft and descended through the thick atmosphere of Saturn's moon Titan, landing on a surface of frozen hydrocarbon slush. It remains the most distant landing ever achieved by a human-made spacecraft.

— European Space Agency, Huygens (spacecraft) — Landed 14 January 2005