Flying on Titan: The engineering of Dragonfly

**Sarah Al-Ahmed** (0:04)
How do you fly a car-sized, nuclear-powered drone through the freezing skies of an alien moon? We're learning more about Dragonfly, this week on Planetary Radio.
I'm Sarah Al-Ahmed of the Planetary Society, with more of the human adventure across our solar system and beyond. Imagine a thousand kilogram drone soaring through a thick atmosphere over organic sand dunes. That's the vision for NASA's Dragonfly mission, which is currently being built and tested for an epic journey to Saturn's largest moon. This week, we're exploring the engineering required to fly a craft of that size in Titan's frigid temperatures. Joining me from the Johns Hopkins Applied Physics Laboratory are Lead Rotor Engineer Felipe Ruiz and Principal Investigator Zibi Turtle. They'll reveal how the mission currently stands in its integration and test phase and how they upgraded the rotor design to get the smoothest ride through the Titanian skies. Then Bruce Betts, our Chief Scientist joins me for What's Up, where we look back at the Ingenuity Mars Helicopter, the first powered controlled flight on another world.
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Titan is one of the most Earth-like worlds in our solar system, despite being frozen and covered in methane rain, rivers and lakes instead of water. But its thick atmosphere and low gravity make it a perfect place to fly. It's about 40 times easier to fly there than it is here on Earth. That's why NASA chose a rotorcraft to explore it instead of a traditional rover. Dragonfly will be able to hop from site to site, covering ground that no wheeled rover could ever reach. It's going to be sampling the organic chemistry of this world that mirrors what early Earth looked like before life ever took hold. To walk us through how this all works, I'm joined by two guests from the Johns Hopkins Applied Physics Laboratory, which manages the mission for NASA alongside a massive team of partner institutions and universities. Dr. Elizabeth Turtle, who goes by Zibi, is the principal investigator on Dragonfly and a planetary scientist whose career spans Galileo, Cassini, the Lunar Reconnaissance Orbiter and Europa Clipper. She's a returning guest and always a joy to have on the show. Felipe Ruiz is Dragonfly's lead rotor engineer and a senior staff mechanical engineer at APL. He's also worked on the Double Asteroid Redirection Test, or the DART mission, and the Parker Solar Probe. Felipe is a long time fan of Planetary Radio, so it's a real thrill to finally have him on. Here's my conversation with Zibi Turtle and Felipe Ruiz.
Hey, thanks for joining me.

**Felipe Ruiz** (2:57)
Thanks, Sarah. Glad to be here. Thanks, Sarah.

**Zibi Turtle** (2:59)
Great to be here.

**Sarah Al-Ahmed** (3:00)
It's been a while since we had an occasion to talk about Dragonfly on the show and we're coming up. There's been a lot of developments recently, so I'm really glad to have you both on. But for people who aren't familiar with the spacecraft, Zibby, can you tell us just generally, what is Dragonfly, why are we going to Titan?

**Zibi Turtle** (3:18)
Dragonfly is a mission to send a rotor craft, a very large rotor craft about the same size as the Curiosity or Perseverance rovers on Mars to Saturn's moon Titan. The moon Titan has a dense atmosphere, and lower gravity than Earth makes it the perfect place in the Solar System to fly.
That allows us, while exploring Titan, to be able to get to a variety of places on the surface, and that's what we really ultimately want to do. Titan is a very carbon-rich place. The complexity of the molecules on Titan is similar to the complexity we think we would have had on the early Earth, and what we really want to study is the kinds of molecules that are being produced there, and whether they're like the kinds of molecules we think would have been produced on the early Earth before life developed. Titan's basically been doing complex prebiotic chemistry experiments, the chemistry that occurred before biology, for an extended period of time, and the results are sitting on the surface. And so Dragonfly is designed to go there to study the composition of those materials and see what's there.

**Sarah Al-Ahmed** (4:34)
I mean, other than trying to blast off from the Moon with some kind of Apollo module or something, there's only ever been one other powered flight on another world, which is the Ingenuity helicopter on Mars. But this is like a much better situation for flying, I feel, with a thick atmosphere and everything that's just waiting there for us. So I'm really excited about this, but we saw about two years out from launch. So where does the mission currently stand in terms of integration and testing?