Engineering department scores NASA hat trick

Five mechanical engineering students at South Dakota State University had their project selected for the finals of a NASA contest, meaning all three of the department’s entries in three different NASA contests have advanced to the finals.

“This honor again reflects the solid skills our students are gaining and the dedication of our students and faculty to pursue student success beyond the classroom walls,” Yucheng Liu, head of the SDSU Department of Mechanical Engineering, said.

Associate professor Todd Letcher, who is the adviser for all three projects, said this is unprecedented for SDSU. “I would guess there aren’t many schools in the country that have this much success in a single year. In the past, we’ve had individual teams that have had success, but I don’t think we’ve even entered three teams in a single year before.”

The most recent team to make finals created a lunar cargo vehicle entered in the Revolutionary Aerospace Systems Concepts – Academic Linkage (RASC-AL) competition.

The other SDSU finalists were in the Break the Ice Lunar Challenge, in which most of the 15 finalists were aerospace companies—SDSU was among four collegiate finalists, and the Formulate, Lift, Observe, And Testing; Data Recovery And Guided On-board Node (FLOATing DRAGON) Balloon Challenge, where the six finalists included engineering bluebloods like Princeton and Purdue.

The SDSU team in the RASC-AL competition was one of 15 finalists in four categories. Other finalists include Massachusetts Institute of Technology, Virginia Polytechnic Institute, Cal Poly-Pomona; Embry-Riddle Aeronautical University, the University of Maryland and the University of Texas-Austin.

A goal-driven team

SDSU chose to compete in the lunar surface transporter vehicle contest, where other finalists are Maryland, Texas and Virginia Polytechnic.

“This category really fit the skills and future career ambitions of the team members. The team members all wanted to learn more about vehicle or robot design and wanted to be involved in the aerospace industry,” Letcher said.

Team members are Liam Murray, Omaha, Nebraska; Jacob Pettit, Dublin, Ohio; Ben Sobczak, Rapid City; Nick Stegmeier, Sioux Falls; and Elisabeth Timmer, Savaneta, Aruba. All are seniors graduating May 6 and heading off for full-time jobs, master’s degrees or in the case of Stegmeier, an internship at Johnson Space Center in Houston.

Murray said, “As space has become more a part of our future thanks to NASA and SpaceX taking big leaps in innovation, it has inspired me to pursue a career in space robotics. The theme of the RASC-AL contest seemed to fit perfect for my dreams in engineering.

“There were other contests such as a lunar forge or Break the Ice that we could have chosen thanks to Dr. Letcher, but making a lunar surface transporter vehicle seemed like a challenge that I wanted to conquer with a team of like-minded individuals,” Murray said.

Looked at ant for ideas

The contest has two different phases—the design of a transport vehicle that could be used on the low-gravity surface of the moon, and a smaller prototype that can be used in a demonstration at the RASC-AL Forum in Cocoa Beach, Florida, June 12-14.

The name of the SDSU project is Artemis Navigating Transporter System, and the theory behind their project draws heavily on its acronym—ANTS.

Murray said, “The initial thought was having multiple robots connect together and form one big robot. We soon realized that would add too many variables. We discussed having several smaller rovers (eventually ANTS) that have many more advantages and functions when it comes to being innovative while accomplishing the competition guidelines.”

Stegmeier added, “We really didn’t discuss ants very much until we were thinking about collaborative robots. Then we realized that ants work together to lift objects many times their body size and weight and decided to design our system to emulate the abilities of ants.”

Letcher explained, “During one of our first meetings, we talked about how we needed to lift very heavy objects while using as little structural material as possible. One of the first ideas, inspired by nature, was to look at an ant—the insect. We knew they could lift many times their own body weight. We also knew they worked together to accomplish tasks that a single ant couldn’t accomplish.

“We did spend some time learning about ants to see how their bodies functioned and what made it possible for them to lift so much more than their own weight. While we ultimately couldn’t use most of those concepts, the inspiration of the ant did help us develop the overall concept of teamwork between robots.”

A forklift built for moon

What the students ended up with was a highly customized forklift.

In their executive statement, the students wrote, “Our lunar cargo transporter features an innovative drivetrain, flexible wheels, a cargo locking mechanism and a universal attachment mechanism for auxiliary systems. The vehicle is adaptable not only for missions on the moon, but for Mars and beyond.”

Using rounded numbers, the design for each forklift is 11 feet by 11 feet and 9 feet high with an ability to lift 16,500 pounds.

Stegmeier explained, “The prototype is about the size of a go-cart while a full-scale ANT would be as large as a Volkswagen Bug, which is quite fitting. Two key features of the ANTS system are the collaborative lift capability, allowing the ANTS to lift very large and heavy payloads such as astronaut habitats, and the use of linear actuators and screws to enable the lifting systems, rather than the typical hydraulic systems that Earth-based forklifts use.

“Hydraulic systems are difficult to use on the lunar surface due the vacuum of space, making it difficult to keep a seal; and the likelihood of lunar dust contaminating the hydraulic system. We didn’t have time to build two ANT prototypes, which would enable demonstration of the collaborative lifting, so we decided to demonstrate the feasibility of a screw-driven lifting system.

“The ANT demonstration prototype has two screw-driven forks that can be controlled individually or synchronously. This enables lifting cargo on uneven terrain. For stability during cargo transport, the entire forklift assembly can be translated over the center of the prototype chassis using another screw and actuator.

“In addition, our prototype can be remotely controlled, just like the real ANTS system.”

‘Out of this world’ excitement

NASA announced the finalists April 11, two months before the teams are to give their presentations. But with students graduating May 6, the time crunch is actually greater than that with students wrapping up prototype construction the week of April 24.

In addition, students are focusing on finishing their final technical report and developing a presentation of their work. “At the competition, all teams will give a long-form presentation on the main stage and will also participate in a poster session where people can ask questions and see the prototype perform up close,” Letcher said.

The first- and second-place overall winning teams will be invited to present their work at the American Institute of Aeronautics and Astronautics conference in Las Vegas Oct. 23-25.

While that would be “out of this world,” students are still pretty excited about being a finalist.

Murray said, “When I got the email, I was freaking out and high-fived her (a teammate on the swimming team) the entire way to practice, and I called my mom right away as well to tell her the fantastic news. I also spammed the team group chat that ‘WE ARE IN.’

“We were very confident, but it was such a relief and celebration to get that NASA email titled ‘CONGRATULATIONS.’”

Letcher added, “I’m very proud of this team. From day one, this team has worked so hard, and they have made my job easy. I know they will do a great job with the presentation this summer and will make us all proud.”

Editor’s note: The finals for the FLOATing DRAGON contest isn’t until August and the Break the Ice final submissions aren’t due until Oct. 27.