Mission

Logo de la mission Dragonfly. Crédits : NASA/JHU-APL

Dragonfly is the fourth mission of NASA’s New Frontiers programme, after New Horizons, which flew by Pluto in 2015 (https://new-horizons.cnes.fr/fr), Juno in orbit around Jupiter since 2016 (https://juno.cnes.fr/fr) and OSIRIS-REx around asteroid Bennu in 2021 (https://osiris-rex.cnes.fr/fr).

The science value of Titan for advancing our knowledge of the solar system and exobiology is clear, especially since the treasure trove of data collected by the NASA-ESA Cassini-Huygens mission from 2004 to 2017 (https://cassini-huygens.cnes.fr/fr). Huygens’ descent through the dense fog shrouding Titan revealed Earth-like landscapes and a complex atmospheric chemistry, with an ice shell, liquid hydrocarbon—methane and ethane—lakes, dunes of organic particles and even ice volcanoes—or cryovolcanoes—fuelled by a subsurface liquid ocean. Titan is an active body with a hydrocarbon cycle similar to the water cycle on Earth. Photo-chemical reactions in its upper atmosphere between nitrogen and methane are thought to be the source of a variety of organic molecules present in the form of aerosols or condensates on the moon’s surface. These processes could also produce chemical species key to the emergence of lifeforms. These are the compelling areas of investigation on which Dragonfly will be seeking to shed new light.

Dragonfly’s great mobility will enable it to explore dozens of sites, 12 of which have already been preselected on its 175-kilometre flight path. It will land in the equatorial dune field at Shangri-La, near the Selk impact crater. Other exploration targets include impact craters, cryovolcanoes and dunes, but not lakes or rivers.

Targets for investigation by Dragonfly. Credits:

The ability to fly a craft autonomously in an atmosphere other than Earth’s was confirmed in 2021 by the Ingenuity rotorcraft accompanying the Perseverance rover on Mars (https://supercam.cnes.fr/fr/). Flying a similar craft on Titan will be possible due to its low gravity (1.35 m/s2, only 14% of that on Earth), dense hydrocarbon-rich atmosphere and high atmospheric pressure (1.5 bars). In this environment the 850-kg rotorcraft will be able to reach a speed of 36 km/h and a ceiling altitude of 4 km, powered by its MMRTG (Multi Mission Radioisotope Thermoelectric Generator) and four pairs of 1-metre-span rotors at each corner.