Joseph Patzer presented his design for a lunar wheel to NASA in a competition in July.
“One of my professors told me about the competition and suggested I do it,” said Patzer, a 2009 Gillett High School graduate and senior at the University of Wisconsin-Milwaukee.
The Lunar Wheel Design Challenge involved designing and building a lunar wheel prototype and demonstrating its capabilities for NASA. The wheels were mounted on a John Deere Gator utility vehicle and then field tested at the Johnson Space Center in Houston, Texas.
The event was part of the Revolutionary Aerospace Systems Concept-Academic Linkage (RASC-AL) competition sponsored by NASA. It was organized by the National Institute of Aerospace.
“I was told to make an OVERSET FOLLOWS:innovative wheel that can traverse soft sand, a gravel pack, loose gravel and a rock field,” Patzer said. The wheels must also be able to handle a climb of 30 degrees, as well as a standard 10-degree grade, he added.
Funding for the project included a $9,000 award from NASA. The university matched that amount, giving Patzer $18,000 to work with.
Patzer began designing his wheel last September. He was the lone member of his design team, designing all parts of the wheel, including the shock assembly and ski pads on the rim. Three graduate students helped him by performing a computer analysis to determine whether the component elements would survive torque during the test.
In December, Patzer submitted a design report to the NASA judging team. In January, he learned he would be one of three finalists for the competition.
In the second phase of the project, Patzer focused on the machining and building of a single wheel to test his theory. In mid-March he performed a mock test and was satisfied with the results.
“I felt I had a good design,” he said.
The focus of his design was based on shock-spokes, which are mechanisms in the wheel that would help deflect it from an object and absorb the impact.
The university has its own machine shop, and Patzer supervised the machining of the shock assembly and center hub of his design there. The ski pads used on the outer rim were machined at home by his father, David.
Working with his dad was both good and bad, he said.
“I could communicate directly with him, which was good, but he kept trying to give input and change things here and there, which made it difficult to keep the design intact. I wanted to show what I could do rather than what someone else could do,” he said.
In mid-July, Patzer, Peng Yang and Stacy Van Dyke, the two students who machined the parts, along with Patzer’s adviser, Professor Rani El-Hajjar, headed for Houston.
On the first day of competition, the three teams field-tested their designs at the Johnson Space Center. Patzer performed the test, and then loaded the Gator with about 700 pounds of weight and ran the test again to show that his wheel design could handle severe conditions.
According to El-Hajjar, the design was innovative in both the wheel dynamics and material uses.
“It incorporated lightweight carbon-fiber composite materials similar to those used in the latest commercial aircraft, like the Boeing 787 or the Airbus A350,” he said. “I believe there is a lot of room to further improve on this design to make it even more lightweight and capable of handling rougher terrains.”
After the teams finished, competitors were allowed to drive NASA’s Chariot Rover, a space exploration vehicle, for about five minutes.
“That was pretty cool,” Patzer said.
The next day each team made its design presentations to the NASA judging team. Patzer’s team placed second.
“It was very eye-opening,” Patzer said. “It was a good experience because we got to go out in the real world and actually build something. Most engineering students don’t have that opportunity until after they’re out of college. We had very strict guidelines, like the time line and budget, and were forced to stay within them.”
Competitors were taken on a tour and allowed access to many off-limit areas of the space center. They learned of job opportunities with NASA after college, but Patzer’s plans have more to do with water than with air.
“I don’t really know what I want to do. Maybe something with outboard engines, maybe work on prototypes somewhere or in research and development,” he said.
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