Thursday, August 19, 2010

Engineering Spotlight: Logan W., AE

Name: Logan W.
Major: Aerospace Engineering
Title: Graduate Research Assistant
Company: Georgia Institute of Technology

Why did you want to become an engineer, and more specifically, your particular type of engineer?

Truth be told, it was a bit of a convoluted path. I grew up under the shadow of Cape Canaveral where my father worked for a time, and my grandfather was involved with the Apollo program. Needless to say I was watching shuttle launches from the front yard before I could understand what I was looking at. While I was interested in the space program, I never really considered actually doing anything related to it; instead I always figured I’d go to med school though I don’t remember why. That changed in high school physics when I realized that the immutable laws of the universe, albeit sometimes unknown, were much more interesting than a study of medicine. Adding to that, I found I would rather do something with this knowledge – application of knowledge, rather than the pure study of knowledge. Thus I decided to be an engineer.

There were two fields of study in physics that I found the most enjoyable and fascinating that I wanted to work in: atomic/nuclear physics and astronomy. For an engineer, the applications opened to me were fission/fusion research for the former and the space program for the latter. It was only in my last year of undergrad (which was in mechanical engineering, as it was the most general major) that I read about the Deep Space missions and the use of ion engines as the primary propulsion unit. One of my professors informed me that Georgia Tech recently picked up a new professor starting a lab researching these types of engines. As this type of technology, called electric propulsion, combined features of both atomic physics and the space program it was too good of an opportunity to pass up. That is how I ended up in aerospace engineering working on electric propulsion.

What do you do? (At your job or in your research)

The kind of research our lab focuses on is prototyping new technologies and testing new concepts, be it new engine concepts or modifications to existing engines. Currently I am involved in two avenues in research: ion engines and helicon plasma sources. Ion engines operate by ionizing a gas to form a plasma. The ions are accelerated out of the engine on an electric field generated between two grids. These engines are characterized by very low propellant consumption rates with very high exit velocity, making the engine very efficient when used over long periods of time. As a rough analogy, think of a car with very low acceleration but very high gas mileage and very high top speed. My involvement is focused in trying to improve the efficiency of the plasma generation within the thruster.

Helicon plasma sources are devices that generate a plasma using radio-frequency waves. Most thrusters in use today ionize their propellant using electron collisions, which can be inefficient as electrons tend to collide with the engine walls, other ions, etc before colliding the desired neutral atom. This wastes energy that could have gone to thrust generation. Helicon sources have been found since the early 1980s to be more efficient for generating a plasma, but the problem is that why it is so efficient is not well understood. I work to better understand how these devices operate and how to predict their behavior and performance given a set of operating conditions.

What do you do outside of engineering?

I am a voracious reader; I’ll read almost anything, from the classics to military history. I also enjoy music, both listening to it and making it when given the opportunity. I must also confess to being a fan of computer games, particularly of the strategy genre.

Anything else you would like us to know about you or your work?

Truth be told, electric propulsion is one of those research areas that doesn’t have a field per se. I am in the aerospace engineering department, but my work is mostly electrical engineering with a mix of mechanical engineering, chemistry, physics, and a little bit of aerospace. So the next time you hear someone talk about “multi-disciplinary fields” don’t snicker too much, you just might find yourself in one.

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