The Middletown Press (Middletown, CT)
Dragonfly heading to Saturn’s moon
Yale scientist assisting mission
NEW HAVEN — If there is life anywhere else in the universe, Saturn’s moon Titan wouldn’t be a bad place to look.
It’s a lot like Earth, except that methane rains down instead of water and its surface temperature is 290 degrees below zero. And it’s that similarity, not a search for life on Titan, that has Juan Lora excited about exploring the moon that’s big enough to be a planet.
Methane on Titan is “very much like water on Earth in the sense that it participates in the hydrologic cycle,” said Lora, an assistant professor of climate sciences in Yale University’s Department of Geology and Geophysics. The methane “condenses in rivers, lakes and seas, and we think there are other hydrocarbons … in those lakes and seas.
“In that sense it’s very analogous to the water cycle of the Earth, which makes it very interesting to study,” he said. “Methane rain helps erode the surface.” There are river channels and gorges, even river deltas.
“That’s just to say that the landscape looks like something we know from the Earth; it’s very familiar. … It’s worth studying. … The low latitudes, which is where we’re going, look like deserts. The low latitudes are covered in dune fields. That’s where we’re headed.”
Lora isn’t headed there personally, of course. He’s a member of the team behind NASA’s Dragonfly mission, which will send what is essentially an eightrotor
drone 886 million miles to Titan, which is bigger than Mercury and would be a planet itself if it weren’t tethered to Saturn’s gravitational pull.
The mission is scheduled to launch in 2026 and Dragonfly would begin flying around Titan in 2034.
Lora won’t speculate about whether there is life on Titan or anywhere else beyond Earth. “Statistically, it seems the most reasonable that there is life,” he said. “Whether we’ll find it or not is a different question. … If we find evidence of life on Titan that will be indication that the universe is teeming with life.”
That’s because Titan’s environment is similar to Earth’s in some ways, “but it’s under very different conditions. The temperature is much lower … so if we find life there … this would mean that life could exist … in many, many environments than we thought for a long time.”
Part of the fascination with Titan is that its crust is water ice, which melts when hit by a meteor, just as the crust of Earth turns to lava at its core. “We know that there’s a lot of water on Titan; it’s just locked up in ice,” Lora said.
“Water on Titan acts the way silicate rocks act on Earth and methane on Titan acts the way water works on Earth,” he said.
More likely than finding life on Titan is discovering “prebiotic chemistry,” the elements that come together to form life as they did in Earth’s early history. “Many people think Titan is a nice analog for the early Earth,” Lora said. Its atmosphere, like Earth’s, is mostly nitrogen with a similar surface pressure.
“There are complex hydrocarbons in Titan’s atmosphere and not just hydrocarbons but very complex molecules,” which include oxygen and phosphorus, Lora said. Smaller molecules in the upper atmosphere combine into larger molecules as they rain down on Titan’s surface.
“These are big molecules. … They’re basically solid particles” that form an orange haze in the middle and lower atmospheres, Lora said. “The combination of having these complex molecules in the atmosphere in combination with having liquid water at some point, that is interesting. … It’s trying to understand how far chemical processes have progressed on Titan.
“Ultimately, this organic gunk from the atmosphere comes into contact with the surface and in a place where we know there was liquid water on the surface. … That’s exciting from the point of view of astrobiology,” or “the study of things related to the possibility of life outside of Earth,” Lora said. “It’s a field that’s been growing in interest for a great period of time, especially with exoplanets.”
Lora’s role in the mission was to assess the climate on Titan in order to determine where to land the rover. Dragonfly will be heading for the Selk crater but will have the ability to travel.
“The beauty of Dragonfly, the design of Dragonfly, is that it’s a quoteunquote lander with aerial mobility,” Lora said. “The flying around means we can explore much bigger distances.
“We are aiming for a place where we know there has been liquid water on the surface previously,” said Lora. “The point here is that essentially Titan’s bedrock, what we think of as bedrock, is water ice.”
The Dragonfly mission will build on the Cassini mission, which explored Saturn and its surroundings for 13 years after its 1997 launch, orbiting the planet 294 times and landing the Huygens probe on Titan.
“Now we know more about Titan’s climate system than we did then but there are still big outstanding questions and Dragonfly will help to address them,” Lora said. “For me some exciting ones are, how does the weather change from day to day and Dragonfly has the ability for the first time to do some environmental monitoring to monitor how wind changes, to monitor how the humidity changes.” Dragonfly also will be able to measure the change in surface temperature between day and night.
“I am really interested in understanding how the climate systems of other planets work because that puts our world in context and the changes in our world in context,” Lora said.
Lora, 32, was born in Colombia and immigrated to the Washington, D.C., area when he was 9. “When I went to college I was studying music and I took astronomy and math classed because I was interested … and it hooked me,” he said. He switched from the violin to studying planets, focusing on Titan since he was a doctoral student.
While there is much talk about sending astronauts to Mars, Lora knows that, because of its similarity to Earth (even at 290 degrees below zero), more will be learned from Dragonfly’s flight about our planet’s early history.