It wasn’t your typical game of ping-pong.
The paddles were hydrophobic, the ball was a sphere of water, and the player was an astronaut orbiting Earth aboard the International Space Station.
And the paddles he used weren’t designed by NASA or a team from Max Planck or other laureled physics institute, but by Karl Cardin, a senior mechanical engineering student at Portland State University.
Cardin built the paddles from a polycarbonate material etched with a geometric, pockmarked pattern and coated with Teflon. That treatment makes the material hydrophobic, or literally “water fearing.”
More specifically, the etched pattern exploits water’s surface tension property to help repel it, allowing droplets to bounce back and forth between the paddles.
Well, bounce, that is, in low- or micro-gravity environments.
Video credit: NASA Johnson/YouTube
On Earth, Cardin tested the paddles in the Dryden Drop Tower at PSU’s Maseeh College of Engineering and Computer Science. The tower allows students and researchers to generate a low-gravity environment (<10-4 g), close to the micro-gravity experienced on the space station (10-6 g).
The goal of creating and playing with the paddles wasn’t about providing diversions for astronauts in space (although fun and games are important when you’re spending several months confined to an orbiting facility with the company of the same handful of people; you might even call it enrichment for astronauts and not that far removed from enrichment activities given to zoo animals).
Instead, it was an exercise in further understanding surface technology and how liquids — which can be problematic in low Gs — behave in space. Insights gained from Cardin’s paddles and Kelly’s testing could have applications in using hydrophobic surfaces to promote heat transfer in spacecraft cooling systems, growing plants in space (a key achievement to reach before any Mars missions) and improving life-support systems.
In fact, Cardin said more experiments with the paddles on the space station are being lined up and that these could lead to technology gains on the station itself.
And as with so many technologies that NASA has experimented with in space, there could be more down-to-Earth uses, such as building water-repellent windshields that don’t need wipers and Rain-X. (Yes, please.)
It’s all pretty neat stuff (even Kelly thought so in the video) and quite a coup of undergraduate science for Cardin, so Science In Portland wanted to find out a bit more about him, how he came to the project, and science and engineering in general. Here’s SIP’s Q&A with Cardin:
1. What is your focus in engineering, and what drew you to it and science and engineering in general?
My focus is in the fluids field of engineering, currently focusing on low-gravity fluids. I was drawn to this field because it represents a great mixture of creative and scientific energy. The phenomena studied are observable by eye and often create wonderful geometries. There are also very elegant mathematical descriptions for the fluid behavior. Engineering was just a natural choice for me. Investigating the physical world and finding solutions to physical problems is what I do best.
2. Where did you grow up, and did you have someone who inspired you in science and engineering as a child? A parent, teacher, mentor? Have you ever mentored anyone?
I think my parents, quite unintentionally, inspired me in engineering and science. I was never pushed toward engineering or the sciences in general. I grew up in an environment where there was a lot of creative energy. My parents owned an automotive repair shop, a hot tub repair company, rental houses, a small farm, and we lived in a 100-year-old house.
Being exposed to all these things meant that I gained an early understanding of how to make things with wood and metal. By high school, I was creating compressed-air rocket launchers with spare parts from the hot tub business and laminating and pressing longboards with remnants from house repairs. In high school, I attended the Center for Advanced Learning [in Gresham] where I thrived being able to work with metal in the machine shop and began coursework that exposed me to describing the physical world with math. I have always found enjoyment in interrogating the physical world to understand it and also in problem solving.
A couple years after graduating, I returned to the center for advanced learning and helped the junior and senior classes with physics and solid modeling. I ended up pushing a lot of the young people I meet toward the sciences.
3. How did you come to design the paddles? Is there a professor or a research team that you’re working with?
I started assisting in research with Dr. Mark Weislogel and his team at the Dryden Drop Tower lab at the beginning of summer 2015. I was approached with the opportunity to make the paddles in July after a previous set was destroyed in a failed SpaceX launch. Without a second set or adequate documentation to create another set, I started from square one to create the paddle for the next launch.
4. Why the hydrophobic paddles? What is it about the materials, surface technology, behavior of liquids or space that fascinates you?
The behavior of liquids in space fascinates me because of the abstract nature of their movement. Obviously, these fluids are not breaking any physical laws, but yet their motion is very nonintuitive. We are seeking to make these movements intuitive through experimental investigations and mathematical models. The investigations of fluid transport in low-gravity environments has many applications. As we seek to extend our reach further into space, we will need increasingly reliable systems. The great thing about taking advantage of surface tension is you can remove many of the moving parts from a system. We are currently investigating multiple life-support systems that are highly reliable and could potentially replace or improve the systems presently being used. We can also apply our knowledge to systems on Earth where the mass is small so gravity is less significant.
5. What other materials, designs or research projects are you working on currently?
Hydrophobic surfaces are, for our group, a means to an end in many ways. We are interested in using hydrophobic surfaces to explore the dynamics of fluids. So what we are most interested in is a cost-effective and versatile super-hydrophobic surface. Because of the necessity of these surfaces to our research, better ways of creating these surfaces are always in our minds, and we have developed some unique ways of making them. Currently, my work is split into two areas. I am assisting research on a NASA Innovative Advanced Concepts project that is looking at taking a large step in a new direction for air revitalization in spacecraft. I am also researching fluid phenomena loosely similar to what was seen with the ping-pong paddles and some other novel phenomena in the drop tower at Portland State.
6. In your recent work with the paddles, studies or other research you’re involved in, what have you learned so far that’s excited you? What have you found most challenging in it?
I have learned a huge amount about the investigative process — how problems are found and how to seek elegant solutions. I have realized that discovery is always just around the corner, especially in the low-gravity field. It seems like every week we are making observation of things that either nobody or very few people have observed before. The most challenging and exciting part is seeing how little I know. The field is vast, and I look forward to seeing where it leads me.
7. Is this the first time you’ve had public exposure for your pursuits in engineering or science? What do you think of that? How was the public or media reception or perceptions of your work? Was that thrilling? Any of it frustrating? Any misconceptions you’d like to clear up?
This is the first time I have had wide exposure outside the scientific community. I find the exposure exciting because of the opportunity to get the word out about the great things that are happening at PSU and share in general the great things that are happening in the local scientific community. One thing I would like to mention, which wasn’t chosen for any of the short TV spots, is that we are working on lining up experiments on the space station with the paddles to get some really great insight into the microgravity fluid behavior. We have a list of about 30 experiments that could be done with the paddles relating to many very important fluids problems. These experiments could lead to some great advancements in technology on the space station.
8. You’re a senior at PSU. What’s next after graduation? Work? Graduate school? Internships? What would you like to end up doing in engineering?
I will be continuing on toward a master’s degree at PSU and always have an eye out for interesting work; I like to stay busy. I like projects that I can be involved in, in some aspect, from start to finish. Moving forward, I would love to work at a startup, on an R&D [research and development] team at an aerospace company, anything technical and new that I can contribute to on many levels. I would love to be on a scientific frontier, the idea of new discovery really excites me.
8. And finally, as a PSU engineering student, you’re part of Portland’s science, technology, engineering and math (STEM) community. How do you like to connect to the STEM community around Portland? (“Community” can include your peers and instructors in engineering, STEM professionals, and science and engineering fans in the general public.)
There is a lot of great research happening, and the students/instructors are usually pretty willing to discuss it, so I keep my ears open. When a problem comes up in the lab, I like calling a local company that might have a better idea of the problem and seeing what they know. Multiple times I have found a company that has had exactly what we need in the local area. Just recently, we had a high school student come to the lab and do an experiment in the drop tower. It is great to see people excited about science.