Alumnus Profile: Kevin Parkin (MS '00, PhD '06)

Kevin Parkin (MS '00, PhD '06, Aeronautics) is a rocket scientist, inventor, and a visionary transforming sci-fi into reality. Currently the Lead Systems Engineer for the NASA Ames Mission Design Center, Parkin has returned to the place he helped establish in 2007, where he began his career after graduating from Caltech. His career highlights include the invention of the microwave thermal rocket, a breakthrough from his graduate studies at Caltech, which he has further developed through collaborations with NASA and DARPA.

In addition, Parkin has served as the Systems Director for Breakthrough Starshot, an ambitious initiative that demonstrated a viable proof-of-concept for sending an ultra-fast, light-driven nanocraft to a nearby star system (Alpha Centauri) within a generation. This project, integrating elements of Parkin's own invention, paves the way for potential interstellar space travel.

ENGenuity spoke with Parkin to discuss his career in aerospace engineering and the profound impact Caltech has had on his life.

ENGenuity: How would you describe your professional contributions and what are you currently working on?

Kevin Parkin: I have a new job. I am the Lead Systems Engineer for the Mission Design Center at NASA Ames. It's sort of a homecoming for me. I helped create that Mission Design Center back in 2007, and since then, the Center has had a humbling array of missions. It is exhilarating to get involved with all these ideas again. I am also excited about Breakthrough Starshot. Since 2016, I have been involved in making real a laser-driven lightsail that goes to Alpha Centauri [the nearest star system to our solar system]. We made enormous conceptual progress—and progress of all kinds—with that project, showing that interstellar travel is possible with known physics. Before that, I invented the microwave thermal rocket. This was something that I started as a graduate student at Caltech. I got a patent on it and had the opportunity to advance it through NASA and DARPA, creating a small rocket to demonstrate the operating concept. We developed the engine with the help of a megawatt millimeter-wave beam at the DIII-D fusion reactor in San Diego, then we launched the integrated rocket using the prototype ‘Active Denial' millimeter-wave system at Kirtland Air Force Base in New Mexico. I have gotten to do a lot of very fun things.

ENGenuity: What is a microwave thermal rocket?

Parkin: The idea is that there is a limited energy density that you can get in chemical propellants. The rockets that we have now are not that energetic; the propellants are not energetic enough to make them very high performance. When you dispense with combustion altogether and you add energy from the outside, you do much better performance-wise. Energy is directed from the ground onto a heat-exchange layer covering the side of the rocket, which in turn transfers it into the propellant where it augments or replaces the energy released by combustion. As a result, you can get a higher payload on a given rocket. The economics of sending things into orbit become orders of magnitude better when you move to directed energy. I once, long ago, had a conversation with Elon Musk about it. I told him if he can get to a few hundred dollars per kg of payload then maybe that is all that's needed to unlock greater demand. Elon pointed out that after that, we'll still want the next order of magnitude improvement. Regardless, thermal rockets are not constrained to chemicals that react together. You can have a single inert propellant, and you can choose propellants that don't have any carbon in them, for example, which may be environmentally gentler on the upper atmosphere.

ENGenuity: How did you become interested in rocket science?

Parkin: There was a TV program in the UK called Tomorrow's World and I used to love watching it. Every week they would have the ideas that came from academia and other places—this was in the 1980s. Occasionally, and very endearingly, they would try to do demos. Often, they failed on live TV. I loved watching that program, but I never saw myself as a scientist or an engineer. My uncle Jay was a satellite engineer for Lockheed Martin in California, and I told the career counselor at school that I wanted to be like my uncle Jay. And she said, well in order to do that you need to take all these classes. It never occurred to me that I would need to shift tracks to do that, and it completely changed my trajectory.

ENGenuity: How has your Caltech education influenced you?

Parkin: I think my Caltech education has been foundational. It completely transformed everything in my life. Before Caltech, I was in the UK, and I was a physicist. I was a Summer Undergraduate Research Fellow (SURF) at Caltech when I was still in undergrad, and I had two summers of that. I started working on spacecraft design tools, and I also had some ideas about wanting to make lower cost rockets. Moving to Caltech involved not only changing countries but also changing from physics to engineering. It transformed everything and allowed me to get where I am today.

ENGenuity: Are there any professors who made a significant impact on you?

Parkin: My advisor, Professor Fred Culick [the Richard L. and Dorothy M. Hayman Professor of Mechanical Engineering and Professor of Jet Propulsion, Emeritus] was wonderful. I remember in the early days he asked me what I wanted to do when I arrived at Caltech. I blurted out a few sentences of I don't know what. He interjected after a sentence or two and said, "ah, an eccentric, we could do with some more of those around here!" He valued someone who was trying to break the usual boundaries between fields and come up with new ideas. He supported me as I dealt with the challenges of Caltech, of changing country, changing from physics to engineering, and dealing with other aspects of my life. I am enormously grateful for that.

ENGenuity: What project are you most proud of in your career?

Parkin: What I like to do is exercise creativity, and I try to do that in all my projects. Breakthrough Starshot has been the most interesting project so far because there aren't many people who have actually looked at how you make interstellar travel real. When I went into this, I thought it was just something from Star Trek, that maybe we could do it in a few hundred years. But one of the most amazing things is that you can do it without inventing any new physics. It is real and you can see how it all plays out. Over the course of the project, we gained many insights, and we figured out how you would actually implement such a thing. I am very proud of that. My role in Breakthrough Starshot was as the systems director, and that entailed making sure that all the pieces fit together to make a working interstellar system. We also had to make the project affordable. The key trade-off we made involved something I took from my work on the microwave thermal rocket at Caltech: the trade-off between the beam size and power vs. cost of the system. It turned out to be enabling for Starshot as well, in terms of making these things affordable. Starshot is deciding what it wants to do at the moment. We have finished phase one, and the rest is TBD. It seems to me that laser-driven lightsails are only ever going to get easier to realize and will happen sooner or later, so I am proud that we laid some of the foundation that whatever comes next can start from, and if we did it right, can hasten their success.

ENGenuity: What advice would you give to recent Caltech alumni?

Parkin: It's important to appreciate the doors that are opened for you by your advisor and your mentors—they nudge you onto the right path. You might not realize it in the moment, but looking back you see it. Sitting where I am today, I can see how the people I met at Caltech and beyond have helped me over the years. Try to pass that on when you mentor others—it is rewarding and occasionally surprising to see the ways in which people mature and flourish.

ENGenuity: What is your favorite story?

Parkin: The first book I ever read in school, at least voluntarily, was The Hitchhiker's Guide to the Galaxy by Douglas Adams. It was wonderful to read. The guy had a mind that was so creative, thoughtful, quirky, and funny. It has always been my favorite story.

ENGenuity: What is your favorite destination?

Parkin: Rome. I never saw Italy when I lived in the UK. I went a few years ago on my honeymoon and it blew me away. You can see that there was this 2000-year-old civilization that had many of the same aspects as ours, in their engineering and especially politically. But there were differences, too. And, seeing what is left sparks questions—how do learned civilizations avoid collapse? You can get a sense of what is really new and what is not.

ENGenuity: What keeps you up at night?

Parkin: Other than mortality, obviously, I would say that something really bothered me once we found a way through with Starshot, with the laser-driven sails. You can see how it might pan out for hundreds of years in the future. Then, you realize those lasers would be visible across the universe and there is no evidence that this has ever occurred or is occurring. You have a renewed question of: why not? Why isn't this happening? What is it we don't know?

ENGenuity: What gets you up in the morning?

Parkin: Other than my husband's alarm clock, which goes off at 5:30 when he goes to the gym, what gets me up in the morning is that each day feels like a fresh slate where you can decide what to create, and you have the chance to bring into the world something new. I love that. I love coming up with new ideas and opportunities to be creative.