PhD student advancing the science of Ice Giant planets at hypersonic speed

Cate Leszcz gazes into her computer screen, analyzing complex mathematical formulas as she seeks to learn secrets of planets over a billion miles from Earth.

The ice giants Uranus and Neptune orbit at the far reaches of our solar system. Leszcz, an aerospace PhD student and Smead Scholar, is conducting computational fluid dynamics research to better understand their atmospheric conditions. This knowledge will be critical for future space probes to the planets.

“Their atmospheres are very different from other planets. We don’t even know their exact composition, which causes all sorts of uncertainties in computational modeling,” Leszcz said.

Here On Earth

A native of Cleveland, Ohio, Leszcz’s path to engineering and space research has been years in the making. She was drawn to science and math from an early age, and in high school, took part in a job shadowing program at NASA Glenn Research Center, located only a few miles from her home.

That led to a college major in aerospace at Ohio State University. Her classroom and lab experiences along with an in-depth summer internship that brought her back to NASA Glenn nurtured an interest in research.

“I did an undergraduate thesis on hypersonics and just loved doing research. I wanted to continue,” she said.

Undergrad to PhD

Leszcz decided a PhD was the next step.

She explored programs and was drawn to CU Boulder for its concentration of hypersonics research. The ample outdoor opportunities in the Rocky Mountains were also a perk.

“The weather is always so nice here so I love being outside, and I have always loved being active as well. Living in Colorado has led me to pursue new activities like skiing, biking, and running and I just did my first half Ironman,” Leszcz said.

She is equally driven on campus, and in 2024 was awarded a National Science Foundation Graduate Research Program Fellowship to further support her work. 

“Being a PhD student is the coolest job ever. It’s about the process of figuring things out, designing a research problem yourself, developing the skills to solve it, and then adding fundamental knowledge,” Leszcz said.

Planetary Mysteries

When it comes to that fundamental knowledge, there is much to learn about Uranus and Neptune. The two planets have been visited exactly once, in brief flybys from the Voyager 2 space probe more than 35 years ago. In comparison, the gas giants Jupiter and Saturn have been the subject of years-long orbital exploration missions. 

Uranus may be on a path for closer study. The most recent National Academies of Science Decadal Survey for Planetary Science and Astrobiology recommended it as a top candidate for the next NASA flagship mission.

Leszcz speaking at the 2025 Smead Symposium.

Any eventual probe will be traveling at hypersonic speeds, more than five times the speed of sound. The atmospheric turbulence that results from such velocities causes the surface of vehicles to heat up to thousands of degrees. 

Improving our understanding of Uranus’s atmosphere now would ease future mission design and operation to endure that turbulence.

“We want to design a heat shield that will protect the vehicle upon its entry but isn’t too thick that it requires more fuel and drives up the cost of the mission,” Leszcz said.

Computational Analysis

Studying the possibilities is extremely complex work, requiring supercomputers like CU Boulder’s Alpine and Blanca systems.

“"I'll disturb certain parameters in my simulations and look at quantities of interest, like the heating a hypersonic vehicle will experience. These are huge sensitivity analyses, running thousands of cases at once,” Leszcz said.

Her research is advancing. Over the summer, she gave public presentations at both the American Institute of Aeronautics and Astronautics Aviation Forum and the International Planetary Probe Workshop (IPPW). Later this month, she will speak at a European Space Agency conference in Italy.

“This topic is really cool and there’s so much to study,” she said. “Initially in grad school you’re learning things that are already known, so you can eventually go further. I’m at the point now where I’m starting to discover things that are new and truly pushing the boundaries of our knowledge. That’s really cool.”