NASA has given SpaceX the contract to launch the Dragonfly mission to Saturn’s moon Titan. A Falcon Heavy will send the rotorcraft and its lander on their way to Titan in 2028, if all goes according to plan, and the mission will arrive at Titan in 2034. Dragonfly is an astrobiology mission designed to measure the presence of different chemicals on the frigid moon.
Dragonfly will be the second craft to visit Titan, along with the Huygens probe and its short visit back in 2005.
Titan is remarkable because it’s the only body besides Earth with liquids on its surface. The liquids are hydrocarbons, not water, though there may be surface deposits of water ice from impacts or cryovolcanic eruptions. Researchers think that prebiotic chemicals are also present, making the moon an enticing target to understand how far prebiotic chemistry may have advanced.
Titan is benign when it comes to powered flight; its atmosphere is dense and its gravity is weak, compared to Earth. Dragonfly is an octocopter, a large quadcopter with double rotors, that can take advantage of Titan’s flight-friendly conditions. It will travel at about 36 kmh (22 mph) and will be powered by a Radioisotope Thermoelectric Generator (RTG), a type of engine proven in multiple missions. The craft is designed to be redundant; it can lose one of its motors or rotors and still function.
Dragonfly will land near a feature on Titan called Shangri-La, east of where the Huygens probe landed. Shangri-La is one of three large sand seas near the moon’s equator.
Dragonfly’s target is the Selk impact structure, near the edge of Shangri-La. Selk is a young impact crater about 90 km (56 mi) in diameter that features melt pools, sites where liquid water and organics could mix together to form amino acids or other biomolecules. Dragonfly will initially land at some dunes near the structure then begin exploring the region and its chemistry.
Thanks largely to Cassini and Huygens, researchers have made progress understanding Titan. In a 2020 paper, researchers examined two types of craters on the moon: dune craters and plains craters. Selk is a dune crater, and in the paper, researchers said that the dune craters are richer in organics than plains craters, and in fact are almost entirely composed of organics. However, Titan’s thick atmosphere makes it difficult to observe, and these findings stem from interpreting albedo and emissivity.
Selk and the other dune craters may have originally had more water ice, according to the research, but much of it’s been eroded away. However, there was a long period of time where the water ice was present, and Dragonfly is heading for Selk to examine the chemistry in the crater and to try and determine if water and organics interacted and if prebiotic chemistry made any headway.
It’s up to SpaceX’s Falcon Heavy to send Dragonfly on its way to Titan. Falcon Heavy has 11 launches under its belt, including the launch of the Europa Clipper in October. After Falcon Heavy launches Dragonfly, the spacecraft will perform one flyby of Earth to gain additional velocity.
It’ll take six years for Dragonfly to reach Titan, and just as it arrives, the entry capsule will separate from the cruise module. With the help of an aeroshell and two chutes, the lander will endure an approximately 105-minute descent. At approximately 1.2 km above the surface, the lander will deploy its skids, and based on its lidar and radar data, will perform and autonomous landing.
From its landing site, Dragonfly will deploy itself and perform a series of flights up to 8km (5 mi) long. There’s diverse geology in the region, and the rotorcraft will acquire samples and then analyze them during Titan’s nights, which last about 8 Earth days or about 192 hours. After that, it will head to the Selk crater.
Titan is an important astrobiology target in our Solar System, and unlike the frozen ocean moons Europa and Enceladus, there’s no added complexity of somehow working its way through thick ice before its potentially biological environment can be examined.
But for all of this to succeed, it needs a successful launch first. NASA is paying SpaceX about $256 million to launch Dragonfly, and it the launch goes off without a hitch, it’ll be money well-spent.