NASA has chosen to commit up to $850 million to creating an interplanetary probe unlike any seen before: a rotor-equipped spacecraft that will fly through the smoggy atmosphere of Titan, Saturn’s biggest moon.
The Dragonfly mission will be managed by Johns Hopkins University’s Applied Physics Laboratory on NASA’s behalf, with its launch scheduled for 2026 on a rocket to be named later, and its landing due amid the dunes of Titan in 2034.
This won’t be the first landing on Titan: That happened back in 2005, when the Cassini spacecraft dropped off the Huygens lander to send back the first pictures from the moon’s cloud-obscured surface. Observations from Cassini and Huygens confirmed that chilly Titan held rivers and lakes of liquid methane and ethane, and that methane fell like rain on the icy terrain.
“Titan is the only other place in the solar system known to have an Earthlike cycle of liquids flowing across its surface,” Thomas Zurbuchen, NASA’s associate administrator for the Science Mission Directorate, said in a tweet. “Dragonfly will explore the processes that shape this extraordinary environment filled with organic compounds – the building blocks to life as we know it.”
Today’s announcement was the climax of a years-long process to choose the next mission for NASA’s New Horizons portfolio, which supports projects costing no more than $850 million. Past selections include the New Horizons mission to Pluto and the Kuiper Belt, the Juno mission to Jupiter. and the OSIRIS-REx mission to bring back a sample from asteroid Bennu.
Dragonfly was chosen over the other finalist, CAESAR (Comet Astrobiology Exploration SAmple Return), which proposed bringing back samples from the comet that was visited by the European Space Agency’s Rosetta probe. Word of the decision sparked cheers of joy and sighs of disappointment on Twitter, as well as at gatherings such as the Astrobiology Science Conference in Bellevue, Wash.
Dragonfly is shaping up as the first full-featured space mission to take advantage of extraterrestrial aerodynamics, following in the rotor wash of the experimental helicopter that’s due to be included on NASA’s 2020 Mars rover. It’s basically a dual-quadcopter that draws power from a plutonium-fueled nuclear electric generator.
JHUAPL’s Elizabeth Turtle, the mission’s principal investigator, acknowledged that a flying space probe may sound unorthodox. But she insisted that the golf-cart-sized craft would be better-suited to the Titan environment than a wheeled rover. Titan’s atmosphere is four times as dense as Earth’s at the surface, and its gravity is only one-seventh of Earth’s, she said.
“Flying on Titan is actually easier than flying on Earth … so it’s the best way to travel, and it’s the best way to go long distances,” Turtle said during a NASA webcast.
If something looks interesting at a site several feet away, Dragonfly could hop on over to take an up-close look, said Curt Niebur, lead program scientist for the New Frontiers program at NASA Headquarters. It could also fly long distances for a total change of scenery.
The current itinerary calls for the probe to travel from the Shangri-La dune fields to the 50-mile-wide Selk Crater, which is thought to hold evidence of organic chemicals and past reservoirs of liquid water. Mission planners expect Dragonfly to take a couple of dozen flights and fly a total of 110 miles over the course of its 2.7-Earth-year baseline mission. And they hope the probe will last significantly longer than that, following the examples set by NASA’s long-lived Mars rovers.
The spacecraft and its instruments are currently in development, with testing conducted under Titan-like conditions at JHUAPL and other locations.
The 10-foot-long spacecraft will be equipped with two drills built into its skids, and suction tubes designed to transfer the drilled-out material into a mass spectrometer for analysis. There’ll be a gamma-ray and neutron spectrometer, plus an onboard neutron generator, to check out the chemical composition of Dragonfly’s surroundings. A seismometer and geophones will document Titan’s quakes and gain insights into the nature of the Saturnian moon’s frozen crust of water ice. There’s even a chance of documenting ice volcanoes.
Titan’s nitrogen-rich atmosphere and its surfeit of organic chemicals have led some scientists to compare its environment to what might have existed on Earth billions of years ago, before the emergence of life. One big difference has to do with the chilly weather: Average surface temperature is in the range of 290 degrees below zero Fahrenheit, or -180 degrees Celsius.
Some even speculate that Titan’s low temperatures and the absence of atmospheric oxygen could allow for exotic silicon-based life. Starting in 2034, we just might find out if that’s the case.