Ph.D. student interns on Pony Express-inspired project

11/1/2021 Debra Levey Larson

Written by Debra Levey Larson

Alex Pascarella
Alex Pascarella

Alex Pascarella is working on a mission concept that will retrieve data from Mars more efficiently. It’s called the Solar System Pony Express, named for a postal service that operated in 1860 between the Midwest and the West Coast using relayed horse-mounted riders—only this express uses a network of satellites.

Pascarella, a Ph.D. student in the Department of Aerospace Engineering at the University of Illinois, is working on the project with a team from NASA’s Jet Propulsion Laboratory.

The Solar System Pony Express is a NASA Innovative Advanced Concept project led by Joshua Vander Hook.

“The technology we're using now to retrieve data from Mars, or from other planets, results in a bottleneck because everything is downlinked via the Deep Space Network,” Pascarella said. The DSN is an array of large radio telescopes on the Earth that supports many interplanetary spacecraft missions. “This shared resource limits the amount of data that can be return from a single mission compared with what could be returned by the Solar System Pony Express.”

Artist’s depiction of the Solar System Pony Express system. Credit: Joshua Vander Hook
Artist's depiction of the Solar System Pony Express system. Credit: Joshua Vander Hook

Pascarella said the idea they are exploring is to enhance the current technology by using a fleet of spacecraft that go back and forth between Earth and Mars on cycler orbits.

The courier satellites use optical communications to receive 1 to 3 petabits from the surveyor at least once per year. One petabit is one thousand terabits. When the cycler spacecraft gets close to Mars, it can uplink a lot of data at once, and then head back to Earth. When it gets close to Earth, it can downlink all of the data again using laser communication.

“To do that, the satellites need specialized orbits that were actually discovered by Astronaut Buzz Aldrin,” Pascarella said. “If we can use these orbits, we can make sure that the satellites going back and forth can get close enough to each planet to use the laser communication to uplink and downlink the data.”

Pascarella said there are a lot of experts from different fields working together to research such the concept. “I’m developing the tools for the trajectory design and orbit analysis—studying the feasibility of using these orbits. My Ph.D. work focuses on low thrust. With this project, we’re using low thrust to target the Earth and Mars flybys and to maximize the payload we can carry on the cycler spacecraft.”

He began working on his Ph.D. last spring with AE faculty member Robyn Woollands. She was already working on the project at JPL before she came to UIUC and helped Pascarella get the internship, which was full time last summer and now part time.

Pascarella also completed an internship at JPL two years ago while working on his master’s thesis in the aerospace department at Delft University of Technology.

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This story was published November 1, 2021.