SHIELD team’s “smart skin” headed to space for testing

In 2023, industrial engineering professor Dr. Robert K. Bradley attended the Texas A&M Engineering Experiment Station (TEES) Annual Research Conference, where groups of researchers collaborated to pitch new research ideas for a chance to win grant funding.

Bradley's group, the SHIELD team, which included researchers from Texas A&M and West Texas A&M University, proposed an idea for a stretchable, elastic "skin" designed to protect a robot's joints, metal and wiring.

"At that time, Boston Dynamics was big with their Atlas robot dogs, so you were constantly seeing pictures of robots in the media-but they didn't have any covering," Bradley said. "They had all these joints just exposed. They're really going to have to do something about that, because if there's post-hurricane relief around a chemical plant and you send robots in, they'll be exposed to all kinds of corrosives. If the robot is working in the desert, it's going to get sand all over the place. If it's on the space station, it'll be exposed to radiation. If it's on Mars, it's going to get Martian regolith. There seemed to be a need for a smart solution to cladding robots."

Named after Marvel's Agents of S.H.I.E.L.D., the team won first place and received a $10,000 seed grant to begin developing their concept. With that funding, they created a silicone prototype cladding, which they tested on a small oscillating robot designed by Bradley.

While developing the robot, the team attended the Texas Space Commission (TSC)kickoff event, where they connected with Aegis Aerospace, the company that had recently taken over NASA's MISSE (Multi-Purpose International Space Station Experiment) program. MISSE allows materials to be tested on an external platform attached to the International Space Station , where they are exposed to the conditions of space for several months.

"The cost of shipping samples is subsidized by NASA. For less than $5,000, you can send a sample up to the International Space Station," Bradley said. "We had a little bit of money left over from the seed grant-about $5,000-so we realized we could actually send our elastomer smart skin samples to the space station. The second year, we pivoted and made space the primary focus."

The SHIELD team's material samples included in the MISSE-22 mission, on a Japan Aerospace Exploration Agency (JAXA) flight. The samples will be exposed to space for six months before returning to Earth aboard a SpaceX flight.

Upon their return, Bradley and his team will begin testing the silicone skin's tensile strength and radiation exposure. Radiation will be measured using three methods: Aegis's radiation sensor, radiation film and fluorinated single-wall carbon nanotubes.

"We have a set of samples we made at the exact same time-half will go to space, half will stay here. We're going to test both so we have a comparison," Bradley said.

The team is testing four different material types, including a pure silicone formulation and another of the same formula enhanced with bismuth nanoparticles, which may help shield against radiation.

"There's a lot we can potentially learn from this one relatively low-cost experiment," Bradley said. "The hope is that with the film and the nanotubes, we'll be able to see how much radiation penetrates through each layer of the sample. Hopefully, the sheets with a higher concentration of bismuth get less exposure than the ones made with pure silicone. The goal is to create a research program where we develop the expertise to do this."

Looking ahead, Bradley said this is just the beginning. With support from Aegis, the SHIELD team plans to continue refining and optimizing their robot cladding formulations.