‘Dragonfly’, a dual-quadcopter, would fly missions around Saturn’s largest moon, looking for regions that might support life.
The Applied Physics Laboratory (APL) of Johns Hopkins University has submitted a proposal to NASA to send a nuclear-powered, instrument-carrying UAV to Titan, the largest moon of Saturn, to determine whether conditions for life exist there. The mission, which would be part of NASA’s New Frontiers program, would take advantage of the dense atmosphere and low gravity of Titan, which make it well-suited for flight, to visit multiple sites on the moon, hopping from place to place like the insect that gives it its name.
New Frontiers-class missions are designed to explore the outer reaches of the Solar system. So far, three missions have flown: the New Horizons probe which visited Jupiter’s moons in 2007, flew on to obtain the first detailed images of Pluto in 2015, and is currently exploring the Kuiper Belt. Two more missions are underway: Juno, which is in orbit around Jupiter and is investigating the composition, magnetic and gravitational fields of the giant planet; and Osiris-Rex, which is on its way to a carbon rich asteroid in a near-Earth orbit – it is designed to take a sample of the asteroid and returned to Earth for study in 2023. A fourth mission is scheduled to be selected for further study later this year.
Dragonfly would be a dual-quadcopter powered by a radiothermal generator (RTG) – a device which uses the temperature difference between a sample of radioactive material and the cold conditions outside the spacecraft to generate an electric current. RTGs have been using the past for probes which operate too far from the Sun or in other conditions where solar power is not practical, such as the Curiosity rover on Mars and the Voyager deep-space probes.
The probe would carry a variety of instruments, including a mass and gamma ray spectrometers to analyse surface and atmospheric samples; meteorology and geophysics sensors; imaging equipment and seismology sensors. Because the conditions on Titan are so suited to flight, the probe could cover tens of kilometres in an hour’s flight; much further than any surface rover could manage. “We could take a lander, put it on Titan, take these four measurements at one place, and significantly increase our understanding of Titan and similar moons,” said Dragonfly project manager Peter Bedini of APL. “However, we can multiply the value of the mission if we add aerial mobility, which would enable us to access a variety of geologic settings, maximising the science return and lowering mission risk by going over or around obstacles.”
Titan is interesting for exploration because it is the only moon in the solar system with a dense atmosphere, which gives rise to Earth -like weather systems based on methane instead of water: it has clouds, rain, and methane rivers along its surface flowing into lakes and seas. The Cassini mission in 2004 and its Huygens lander further revealed that it has a salty water ocean beneath a water-ice surface crust. NASA has identified such ‘ocean worlds’ as priorities for investigation because they are believed to have the potential for the chemical processes that began life on Earth, and Titan is particularly interesting because its methane-rich atmosphere means it also has organic chemistry, driven by the ultraviolet fraction of sunlight.
Peter Bedini discusses Dragonfly in this video: