Assistant Prof. Zach Putnam

New Assistant Prof. Zach Putnam will bring to Aerospace Engineering at Illinois expertise in hypersonic and space systems, with an emphasis on planetary entry, descent, and landing systems.

“One of the really cool things about planetary entry is that we do everything from a systems perspective,” he said. “(Planetary entry) involves tightly coupled components and systems: a change in every little piece absolutely affects everything else….(Planetary entry is) a tough problem that we’re still learning how to solve.”

Developing analytical methods to evaluate ways to change drag areas for hypersonic space vehicles and improve trajectory control has been the subject of Putnam’s doctoral work, completed in May at Georgia Institute of Technology, where he also earned his bachelor’s and master’s degrees.

“The work I did for my thesis was largely motivated by the need to develop better steering methods for new classes of planetary entry, descent, and landing vehicles NASA is developing,” Putnam said. “Many of these new vehicles deploy a big drag area to help the vehicle slow down; it’s like the difference between (slowing) a bowling ball and a beach ball.

Graphic showing planetary entry.

“When you have big drag areas, you can steer  the vehicle just by changing the drag area – you don’t need any lift. It simplifies the entire entry, descent, and landing system while providing performance similar to the current state of the art.

“The most logical extension of my PhD research is to determine how large of a payload we could land on the surface of Mars using these drag-modulation techniques,” Putnam said. “I also intend to explore coupling the analytical methods I developed to build linear covariance analysis tools for high-speed atmospheric flight.”

In continuing his work, Putnam expects to collaborate with AE faculty including Associate Prof. Soon-Jo Chung, Prof. Vicki Coverstone, Prof. Debbie Levin, and new Assistant Prof. Kai James. He also plans to collaborate with personnel at NASA’s Jet Propulsion Laboratory and Johnson Space Center.

While much of Putnam’s work is computational and theoretical, he envisions creating a guidance, navigation and control (GNC) system laboratory in AE.

“My long-term goal is to build up infrastructure that would include hardware, navigation equipment, flight computers and flight control factors so that we can really look at GNC systems as a whole,” he said. “That would enable a lot of design and architecture studies, and establish rigorous connections for high level mission requirements.”

Prior to his doctoral studies, Putnam worked at The Charles Stark Draper Laboratory, Inc., in Cambridge, Massachusetts, and in Houston, Texas. He led the development of the entry guidance algorithms for NASA’s Project Orion. He also served as technical advisor for two master’s degree engineering students.

In addition to his research, Putnam will teach AE 442, Senior Space Systems, in the fall, and the second semester of that course, AE 443, in the spring.

In choosing Illinois over other universities to begin his faculty career, Putnam said: “It was clear from the get-go that the Department was very well organized. Also, I am really excited about the (Department’s) emphasis on mentorship for assistant professors; I thought this is a place where I could succeed.”