Carol Paty

Story by Lauren Bruce, CHC Communications
Photo by Sarah Northrop, CHC Communications

Carol Paty, an associate professor at Clark Honors College, didn't need to actually be in space to make a huge leap. She was, indeed, grounded on Earth when The National Academies of Science, Engineering, and Medicine asked Paty to join their panel of scientists who will spend the next 18 months creating a roadmap for the next ten years of planetary exploration and making reccomendations to NASA.

This isn’t Paty’s first round of volunteer work for NASA; in fact, she’s worked with the panel before, co-authoring on a white paper titled “Neptune and Triton: A Flagship for Everyone.” The paper encouraged NASA to prioritize a space mission to Neptune and one of its moons, Triton. There was also a Planetary Mission Concept Study on the topic led by the Johns Hopkins Applied Physics Lab, which Paty participated in last year. Flagship missions, the largest in the portfolio of NASA exploration missions, are difficult to mount as they occur less than once every decade. The cost, the long launch cadence, and the long development period makes deciding the target destination a difficult task. Paty explains that everyone has a “favorite planet” and different opinions on where the unmanned spacecraft should go. Neptune and Triton orbit the sun approximately 2.8 billion miles from Earth, a distance that no person could travel to with current technology. For comparison, our moon orbits a mere 238,900 miles away.

“If you’re going to have a Flagship mission, which is the biggest class mission we fly,” Paty explains, “it should be a mission that engages the broadest number of people; it’s not just for one niche of the planetary science community.”

According to Paty, a mission to Neptune and Triton would interest a wide cross-section of scientists in the planetary community. Neptune is one of two ice giant planets in our solar system, and we have barely scratched the surface in terms of understanding their interiors, evolution, atmospheric dynamics and magnetic fields. Neptune and Uranus were visited only once, with brief flyby encounters by the Voyager 2 spacecraft in the late 1980’s. Triton’s diverse geology, potential for harboring a subsurface ocean, and its likely origins from the Kuiper Belt make it an enticing target of study. Triton is the largest of Neptune’s moons and is “the only moon in our solar system that orbits in the opposite direction of its planet's rotation,” according to NASA, a characteristic indicative of its orbital capture. Its young icy surface is crusted with frozen nitrogen, water and carbon dioxide, and expresses tectonic features, “cantaloupe terrain” indicative of thermal processing, cryovolcanism with windswept plumes and surface deposits – a veritable playground for planetary scientists. Triton itself is such an exciting target that Paty is also part of the Trident mission team competing for a smaller Discovery class mission to explore this unique moon.

“What I find truly thrilling has been the opportunity to work with other like-minded people around the world, researchers who are excited about planetary exploration and can talk and have discourse about the science,” Paty said. “I’ve made some of my best friends and some of my most meaningful connections with people I’ve had the pleasure of working with on these projects.”

While that Flagship mission has not been selected yet, for now Paty is one of the scientists working on another Flagship mission that’s already been selected. The Europa Clipper, a spacecraft that will orbit Jupiter and study the icy ocean world of Europa, is set to launch in 2024. Out of nine instruments selected for this mission, Paty is working on two. In 2014 scientists began proposing instruments that would be included on Europa Clipper, and since 2015 they have been working on how to incorporate the nine instruments onto this spacecraft and have them work in harmony. The primary objective is to detect and characterize the global ocean that reside between four-50 km beneath Europa’s icy surface, a challenging task to do while orbiting Jupiter.

“How do you study something that’s impossible to access directly?” Paty asks, reflecting on the intricacies of learning about the interior of a moon that is half a billion miles from our own. “How do you study the invisible?”

The goal to determine the salinity, the depth and thickness of an ocean you can’t see or sample directly is challenging. The primary technique used to first identify Europa’s ocean with the Galileo spacecraft in1998 was magnetic induction, measuring small changes to the magnetic field around the moon as the spacecraft hurtled by at ~10 km/s — or more than 22,000 miles an hour.

According to NASA’s website, there’s “strong evidence” that Europa has an ocean under its crust, providing the possibility of a habitable environment for life beyond the Earth. The Europa Clipper will allow scientists like Paty to utilize radar, mapping, and magnetic sounding instruments to investigate this ocean as Europa Clipper orbits around Jupiter, flying close to Europa 45 times over the course of the primary mission. The Europa Clipper mission will also help determine whether and where NASA might land a spacecraft in the future and drill through the ice.

These intricacies and questions have always peaked Paty’s interest in planetary science. “When I was an undergrad I realized there was a career path in planetary science and I thought, ‘Why wouldn't everyone do this; it’s so exciting,’” she said.

Now with the Europa Clipper under development, Paty hasn’t stopped yet. Her new project will be an equally exciting opportunity for her career. She’s been invited to assist on a new panel of scientists who will “identify the most important scientific questions to be addressed during the interval 2023-2032.”

“It is both a huge honor and a somewhat overwhelming amount of work,” Paty said, “but I am very excited to be a part of assembling this important steering document for the planetary and astrobiology community.”