UNIVERSITY PARK, Pa. — Jack Langelaan, an associate professor of aerospace engineering at Penn State, was uncharacteristically animated. He leaned forward, his hands punctuating his words as he described the great achievements of humanity.
“The Egyptians built the pyramids; medieval Europeans built the cathedrals,” he said, taking a breath and leaning back in his chair. He gestured to his colleagues sitting on either side of him. “And our society builds space vehicles.”
Sven Schmitz and Jose Palacios, both associate professors of aerospace engineering at Penn State, nodded in agreement. All three grinned.
“Something we build is going to Titan! This is the dream!” Palacios exclaimed. His excitement bubbled over, and the grins turned to laughter.
These three engineers are leading the Penn State team on an $850 million NASA mission spanning at least the next two decades. The Johns Hopkins University Applied Physics Laboratory (APL) leads the endeavor — dubbed "Dragonfly" — to investigate surface and atmospheric conditions of Saturn’s largest moon, which in many ways appear to be strikingly similar to Earth’s primordial state.
In June, NASA announced that Dragonfly would be the fourth mission under its competitive New Frontiers program, which funds projects that shed light on scientific mysteries of the solar system. Dragonfly is scheduled to launch in 2026 and reach the surface of Titan around New Year’s Eve in 2034.
For engineers who built their careers by understanding how vehicles fly on Earth, the opportunity to develop a vehicle that will explore Titan is almost unbelievable.
The phone call
Penn State is home to one of three national Vertical Lift Research Centers of Excellence designated by the United States Army, Navy and NASA. A collaborative effort between academia and government, the centers provide resources to advance vertical lift research while also training the next generation of flight engineers. Georgia Tech and the University of Maryland in College Park house the other two centers. Langelaan, Palacios and Schmitz are all affiliated with the center, where they specifically focus on helicopter design and advancement.
“Three years ago, APL called us for help on this project,” Langelaan said. “They wanted to go to space, and they needed helicopter people.”
The team at APL envisioned something more than the traditional land rovers that roam Earth’s Moon and Mars. A flying probe couldn’t capture the samples and conduct the science they wanted. They needed a drone.
Zibi Turtle, the Dragonfly principal investigator at APL, said that Dragonfly was designed to be a rotorcraft to explore Titan because “it’s the best way to travel and be able to make science measurements in multiple locations in Titan’s environment.”
Titan is a world with a deep liquid water ocean in its interior and an Earth-like surface with sand dunes, lakes and seas on the surface. But at Titan's surface temperature of minus 180 C, the sand is organic, and the lakes and seas are filled with liquid methane — methane even forms clouds and rain. With conditions that may replicate aspects of Earth’s chemistry before life developed, Titan could offer a unique glimpse into how chemistry becomes biology, according to Turtle.
“They needed a drone that could land, collect samples, run experiments and fly again,” Schmitz said. “Those requirements pose unique design problems in Earth’s atmosphere. On Titan, where it’s minus 180 C, things can get more complicated. We were interested.”
“Getting that call from APL was fun,” Langelaan said. “And then we did a lot of work during our own time and using our own research development funds.”
Nuts and bolts and blades
NASA’s highly selective New Frontiers Program doesn’t offer any funding during the early phases of the competition.
“We are lucky to work in a department at a university where curiosity and individual pursuits are valued,” Schmitz said.
Palacios added: “And where our industrial pursuits are supported. We can actually cut metal to test theories here. Other universities might not have been happy providing so many resources up front in pursuit of a project that wasn’t guaranteed to be funded.”
The College of Engineering’s Department of Aerospace Engineering internally funded the team’s preliminary work in part. Langelaan, Palacios and Schmitz also kicked in money from their discretionary funds to buy the parts needed for their first prototype vehicle.
“As with all exploratory research, what you think you’re developing could lead to very different, unintended applications,” Langelaan said. “There’s also a lot of work that needs to be done to figure out what work is necessary. The good thing about research is that even when things don’t turn out as expected, we learn something.”
In January 2018, Dragonfly and a Cornell University-led project called the Comet Astrobiology Exploration Sample Return (CAESAR) were selected as the two finalists. At that point, NASA provided a year of funding for both projects.
“That was nice,” Palacios said. “We’re in the aerospace engineering department, but we’re all focused on the aero part. To have NASA funding for a potential space mission? The project turned from something that was interesting to something that could be real. That was exciting.”
The Penn State team, responsible for the aerodynamics and rotorcraft design portions of the drone, used some of the funds to develop a 45% scale prototype. It’s reminiscent of an actual dragonfly, with a dark, spiny body and four wings. Each wing is stationary, holding stacked rotor blades. All eight rotors need to move independently in extremely cold conditions.