I have always been fascinated by space, so when the Space Grant office contacted me out of the blue when I was a junior and asked me if I was interested in applying for the NASA Academy, a program where you spent the summer at NASA doing research and meeting fascinating people in and around Washington, DC, it didn't take me very long to decide this was a great idea. Once I went over to the office and had a chance to look through the possible research projects, I got even more excited, because buried in the list was "Microthruster for Microsatellites," a project to try and build a laser-ablation propulsion system for use with very small spacecraft. I was ecstatic, because not only have I always been fascinated with space, I've also always wanted to be a rocket scientist, and here was my chance!
I was lucky enough to be accepted to the program a few weeks later. I'll never forget getting the call from Jerry Soffen himself one Sunday afternoon telling me that I'd been selected. I figured that if he was committed enough to be calling people from his home on a Sunday, this was going to be a great program. I was right! But even then I couldn't have possibly imagined what this one summer would turn into.
The summer itself was amazing. My research supervisor, David Skillman, is an amazing individual who taught me too many things to even begin to mention. We proceeded to design and build a vacuum chamber torsional thrust stand for eventual thruster testing; a thruster test article; and a fuel test cell where different kinds of fuels could be tested with the laser. Unfortunately time ran out on the summer before we were able to test the thruster itself, but I learned an incredible amount, and had a great time.
I returned to MIT as a senior, and soon had to begin to worry about what I was going to do with my life in the coming years. I was leaning towards grad school and in the late fall walked into Prof. Jack Kerrebrock's office carrying a hard copy of the final presentation I had given at the NASA Academy summarizing my research. I told him I was interested in propulsion and specifically in micro-propulsion, and ran through the presentation. He seemed excited. After talking to some colleagues of his in industry, he became more aware of the need for propulsion for small spacecraft, and we decided to look for some funding to do graduate work in the area. His idea was that we start by looking at the larger, more general problem: of all the different propulsion technologies out there, which would make the most sense for use on small spacecraft? We wrote a proposal to Goddard for a NASA/GSRP fellowship, as well as one to the local Spacegrant office for a Spacegrant fellowship. Luckily enough, I was awarded both, and was able to begin my graduate work.
At the same time, a friend of mine from the Academy, Robert Bayt, was accepted to MIT for his Ph.D., and joined our department. He too was interested in propulsion, and had been very interested in my project over that summer. He eventually found a project funded by JPL, working on MEMS-based space propulsion. This is the propulsion required for spacecraft and satellites even smaller than the ones I was considering in my research. We, along with a couple of other students, formed a micro-propulsion research group. My research went well, and after a year was able to write my thesis, "A Systems Study of Propulsion Technologies for Orbit and Attitude Control of Microspacecraft." In it, I found that there were a few different propulsion technologies that looked very promising for use on future small spacecraft.
Of these, one was a micro-chemical bipropellant rocket. MIT has a project (which was approximately a year old at the time) to develop a micro-gas turbine engine. The originator of this idea, Prof. Alan Epstein, was talking to Prof. Kerrebrock at one point during the spring, and suggested that the same kinds of turbomachinery they were planing to use in the gas turbine engine could be applied to liquid fuel pumps for use in rocket engines at very small scales. In my research I had realized that there are some significant advantages to very small chemical rockets, particularly if they can be produced cheaply and reliably. They look even more promising if they can be pump-fed, as he was proposing, thus eliminating the need for high-pressure propellant storage tanks on spacecraft which are notoriously heavy.
I choose to focus my efforts for a Ph.D. on developing this technology. I was still receiving my NASA/GSRP from Goddard, and we found some preliminary funding from NASA/Lewis's Onboard Propulsion Branch. I spent the Fall of 1996 working with another student, Omar Al-Midani, on a feasibility study for the micro-rocket engine, and we presented our results to NASA/Lewis in December. They are extremely excited and have agreed to begin funding some preliminary experimental work to attempt to verify some of the results of our feasibility study. For instance, we think we require cooling passages with widths as small as a thousandth of an inch in some locations, and it is not completely clear that traditional analytical tools and correlations will be accurate at these scales. There are a number of other issues to explore in more detail as well.
It quickly became clear that we were under-staffed for what we had promised to accomplish, so we went looking for additional graduate students. Luckily, the NASA Academy came through for us again, and Jake Lopata, one of the students from the summer following mine, had been admitted to MIT, and was looking to start up his graduate program in propulsion this coming fall. We managed to convince him to drop everything and move up here immediately, and as of a month ago, joins us as the third student on our project
So now, through a few twists and turns, my little summer project for the Academy that began by me reading a few lines about laser powered propulsion in my Space Grant office three years ago, is quickly becoming a fairly major propulsion research effort in our department, having yielded me a Master's degree and a Ph.D. program,and two different masters programs for Jake and Omar. With talk of our becoming even more funded in the fall, perhaps an additional three more students and a post-doc will join the fun in the not to distant future.
As I ponder the last few years, it reminds me of the end of a Robert Frost poem I first heard in grade school, but that has always stuck with me:
I shall be telling this with a sigh
Somewhere ages and ages hence:
Two roads diverged in the wood, and I--
I took the one less traveled by,
And that has made all the difference.
I have no doubt that in five and again in ten years, I will look back on my micro-rocket experience, and remember the NASA Academy where it all began, and realize how it has made all the difference!