Titan Saturn System Mission
Titan Saturn System Mission (TSSM) was a joint NASA–ESA proposal for an exploration of Saturn and its moons Titan and Enceladus, where many complex phenomena were revealed by Cassini. TSSM was proposed to launch in 2020, following which it would have gotten gravity assists from Earth and Venus, and arrived at the Saturn system in 2029.
Source: Wikipedia — Titan Saturn System Mission (CC BY-SA 4.0)