Exploring the Seas and Skies of Titan

Saturn’s moon Titan may be my favorite place in the solar system. The creature comforts of Earth notwithstanding, our planet can be incredibly complicated to study—everything here is so intricate and so teeming with life that we often need to look out into the solar system for analogs to help us understand the basic mechanisms here at home. And that’s what makes Titan so extraordinary. It lacks pesky things like people and plants that can interfere with scientific observations, yet it has so much of what we take for granted here on Earth—lakes and seas, wind and tides, even volcanoes—that it is irresistible to a planetary scientist like me. And we still haven’t ruled out that those seas may host something on a path to life.

Although Titan is the only moon in our solar system with a thick atmosphere and the only place other than Earth with surface seas—some as large as the Black Sea—it is as alien a world as you could imagine. Because it is about 90 million miles farther from the sun than Earth, with temperatures around −290.5 degrees Fahrenheit,
all of these otherwise familiar environmental features occur in wildly exotic circumstances. The liquid on the surface of Titan, from the rain to the rivers, is methane and ethane—basically gasoline. And the rocks are mostly made of water ice—so cold they fracture and erode more like river rocks than ice cubes.

Because Titan is so alien, the plans to explore it have been as creative as any science-fiction film. There have been proposals for Montgolfier balloons to ride the winds, an autonomous airplane to glide through its atmosphere, and—closest to my heart—a boat to sail its silent seas. Those missions may fly one day. But for now, we will have a Titanian drone. On p. 56, you can read more about Dragonfly, which will launch toward Saturn in 2026.

Fourteen years ago, Cassini took the first radar images that showed methane lakes on Titan. I was on the science team that analyzed that data—and I will never forget waiting for those images to appear on our screens, followed by the thrill of discovering something at once so strange and so familiar. Titan will teach us many things about Earth, but the spark of pure discovery is waiting for us there too. Although there won’t be any astronaut footprints on Titan when Dragonfly alights, this is human exploration at its finest.

Ellen Stofan | READ MORE

Ellen Stofan, formerly the John and Adrienne Mars Director of the National Air and Space Museum, is Under Secretary for Science and Research at the Smithsonian.