Planetary protection considerations for Dragonfly at Titan

Titan is an object of great interest in studying the chemical origins of life, but it is intensely cold and cannot support ‘life as we know it’: it is therefore designated a Planetary Protection Category II* target. Titan is thought to have an internal water ocean, but it is isolated beneath an approximately 100 km thick ice crust. Herein, the particulars of the Dragonfly rotorcraft lander mission and the Titan environment are reviewed, demonstrating that inoculation of the ocean with viable terrestrial biota by the mission is a very low-probability event (much less than 10−4), thereby consistent with a mission designation of Category II. This article is part of the theme issue ‘Planetary Protection for sustainable space exploration’.