Mike Hepler received his PhD in Princeton’s Mechanical and Aerospace Engineering Department in May 2020. Since joining SGS in 2016, he worked on several nuclear arms-control treaty verification projects including item tagging, electronic information barriers, and his thesis research on zero-knowledge nuclear warhead verification. Mike was a Graduate Fellow of the DOE-funded Consortium for Verification Technology and has conducted research and training at National Laboratory facilities. Mike previously worked in Princeton’s Electric Propulsion and Plasma Dynamics laboratory conducting research on the stability of plasma thrusters and on liquid-metal propellant feed systems for spacecraft propulsion. He holds a Bachelor of Science degree in both Physics and Astrophysics from the University of Minnesota.

Research Interests


Mike’s current PhD thesis research is focused on developing a novel method for nuclear warhead verification using zero-knowledge proofs. Previous experiments conducted at Princeton University and the Princeton Plasma Physics Laboratory have demonstrated the ability to discriminate geometric and material differences of test-object configurations under zero-knowledge conditions. In order to create a robust protocol, Mike has designed and will carry out an experimental zero-knowledge demonstration of isotopic discrimination using a newly-designed moderated neutron collimator. He is also performing research using machine vision techniques for more precise counting bubbles in non-electronic superheated emulsion detectors. He maintains interest in policy issues surrounding the militarization of space and the use of fissile materials for spacecraft power and propulsion.



M. Hepler, S. Philippe, A. Glaser, R. J. Goldston, and F. d’Errico, Not So Fast: Tailoring 14-MeV Neutrons for Zero-Knowledge Isotopic Comparison of Uranium Objects, 59th Annual INMM Meeting, July 22, 2018.

R. Goldston, P. Kunkle, A. Glaser, M. Hepler, Joshua E. G. Peek, and S. Philippe, Machine Vision for Imaging Bubbles: From the Interstellar Medium to Neutron Detectors for Zero-Knowledge Warhead Verification, 59th Annual INMM Meeting, July 22, 2018.

W. J. Coogan, M. Hepler, and E. Y. Choueiri, Method for Measuring the Applied-Field Thrust Component of Plasma Thrusters, Journal of Propulsion and Power, August 31, 2018.

M. Hepler, W. J. Coogan, and E. Y. Choueiri, Liquid-Metal Mass Flow Measurement by an Inductive Proximity Detector for Use in Conjunction with a JxB Pump, 52nd AIAA Joint Propulsion Conference, Salt Lake City, UT, AIAA-2016-4536, July 25-27, 2016.

W. J. Coogan, M. Hepler, and E. Y. Choueiri, Direct Measurement of the Applied-Field Component of the Thrust of a Lithium Lorentz Force Accelerator, 52nd AIAA Joint Propulsion Conference, Salt Lake City, UT, AIAA-2016-4537, July 25-27, 2016.

W. J. Coogan, M. Hepler, and E. Y. Choueiri, Dynamic Resistance Probe for the Measurement of the Mass Deposition Rate from a Condensable Propellant Thruster, 34th International Electric Propulsion Conference, Hyogo-Kobe, Japan, July 4-10, 2015.