SLUSH : Thermo-Mechanical Drilling on Europa
SBIR1 at Honeybee Robotics
Fall 2017 - Winter 2018
I was the project lead for SLUSH, a SBIR (Small Business Innovation Research project) awarded to Honeybee Robotics in partnership with JPL. The project explored three different approaches for penetrating through the 10-30km thick glacial crust on Jupiter’s moon Europa: hot-point melting, mechanical drilling, and thermo-mechanical drilling ("slushing").
SLUSH TESTBED IN WALK-IN FREEZER
SLUSHING IN -20C ICE
Hot-point melting is a well established method for penetrating through glacial ice, but is slow, energy inefficient, and can be defeated by the presence of sediment. Mechanical drilling is fast and efficient, but mechanical probes must actively transport the ice cuttings aft of the probe and then recompress them to avoid getting stuck. SLUSH combines the best of both options with a heated drill bit that partially melts the ice cuttings so that the buoyancy of the chips facilities transport along the probe and the natural refreezing recompresses the slushy mixture.
AMNH STYLE BIT
WATSON STYLE BIT
HEATER CONTROL (LEFT) AND DRILL CONTROL (RIGHT)
I designed four different drill bits with integrated heaters, as well as control and feedback electronics and software. Using the two bits pictured above in -20C ice, we demonstrated that thermo-mechanical drilling is ~10x more efficient than hot-point melting, ~10x less efficient than mechanical-only drilling, and effectively handles the issue of cuttings compaction behind a probe.
MELTING
SLUSHING
DRILLING
The project was delivered on time and considered a resounding success by our JPL customers. I helped write two proposals for further funding from NASA's Research Opportunities in Space and Earth Sciences (ROSES) program; both proposals have since been selected to mature the SLUSH technology. Based on the proposed concept for a nuclear SLUSH probe that could penetrate through Europa's crust, Honeybee's business development team created the promotional video below.
Conference papers and presentations have been published in the 2018 IEEE Aerospace Conference and 2019 Astrobiology Science Conference that further detail the project and findings (see Publications). The original SLUSH testbed that I developed continues to be used to gather data and test prototypes.
Publications
SLUSH: Search for Life Using Submersible Heated Drill. Zacny K, Hand K, Sotin C, Howell S, Cwik T, Mueller J, Ehlmann B, Nagihara S, Tipton M, Liller S, Rehnmark F, Costa JT*, Bergman D, Hovik W. Proceedings of the 2019 Astrobiology Science Conference (AbSciCon), June 2019. In Press.
Abstract, Presentation, Video
SLUSH: Search for Life Using Submersible Heated Drill. Zacny K*, Costa JT, Rehnmark F, Mueller J, Cwik T, Zimmerman W, Chow P. Proceedings of the 49th Lunar and Planetary Science Conference, August 2018. #2083
Abstract, Presentation
SLUSH: Europa Hybrid Deep Drill. Zacny K*, Mueller J, Costa JT, Zimmerman W, Gray A, Cwik T, Chow P, Rehnmark F, Adams G. Proceedings of the 2018 IEEE Aerospace Conference, June 2018. DOI: 10.1109/AERO.2018.8396596
Abstract, Presentation
*Presenter