PASADENA,Calif. – 15 August 11
JPL Intern Pierces the Core of Drilling Mechanics
By: Heather L. Ogletree
Many projects that interns at NASA work on are on-going efforts where they are continuing the work of previous students. It is not often that interns get in on the ground floor of a project; however, this spring, Lukas Domm, a junior studying at Dalhousie University in Halifax, Nova Scotia, got to experience being a part of the initial design, fabrication and testing phases of an exciting new drill at NASA’s Jet Propulsion Lab (JPL).
Domm’s mentor, Yoseph Bar Cohen of JPL's Advanced Technology Group said, “This project is about developing a rotary hammer drill that is driven by vibrations generated with a novel single piezoelectric actuator.” Domm added, “The [drill’s] design was conceived by Dr. Stewart Sherrit,” and as this truly is a novel drill, the group has filed a patent for his design.
Previous drills used in exploration missions relied on gears and motors to move the drill bit; however, this piezoelectric rotary hammer drill requires neither, making it both lighter and more energy efficient since it requires fewer components. Other advantages associated with piezo actuators include the ability to make drills that operate at extremely high or low temperatures as well as the significant increase in drilling rate and reduction of the weight-on-bit as compared to drilling with rotation only. Domm indicated that the many efficiencies created by the piezoelectric actuator would benefit future sample collection from terrestrial bodies, sighting the concept of a piezoelectric rotary hammer drill as “very unique”.
Domm explained, “The principal is that rotation and hammering are produced simultaneously by amplifying the high frequency vibrations produced by a stack of piezos through a ‘horn’ with angled cuts. The tip of the horn tends to rotate as it extends because of the angled cuts, and imparts rotary and linear momentum to the drill bit.”
Before coming to take part in this 15-week opportunity with the Undergraduate Student Research Program (USRP), Domm admitted, “I hardly knew what the term piezoelectrics meant, I had never used finite element software, and I had no machining experience. The learning curve seemed almost too big to be able to accomplish anything in the few months I had here. However, spending every day on a single project really allows you to soak in the details.”
Domm originally was on the path to study music until his final year of high school. The music world’s loss was NASA’s gain; Bar-Cohen rated Domm as excellent across the board from productivity to professionalism. The highlight of the project for Domm was when he turned on the drill for the first time and saw it work exactly as the computer models, or simulations, had predicted.
Domm reflected, “The best thing about this [USRP] internship for me has been the opportunity to be a part of such a large chunk of the product development life cycle. I have gotten to work on the design, fabrication, and testing of the drill I have been working on. It has been rewarding and eye-opening – not to mention all that I have learned from the people I work[ed] with.”