Dr. Polk is a Principal Engineer in the Propulsion, Materials, and Thermal Engineering Section at the Jet Propulsion Lab, and a lecturer in Aerospace Engr. at Caltech. He received a BS in Aero. Engr. at Georgia Tech and a PhD in Mech. & Aero. Engr. from Princeton. Dr. Polk is an expert in high‐ current cathode physics, EP wear processes, high power EP, and probabilistic methods to analyze engine life. He was the task manager for an 8200 hour wear test of a 2.3 kW ion engine as used on the Deep Space 1 mission, was a co‐investigator in the Next Generation Ion Propulsion Program and principal investigator of the Nuclear Electric Xenon Ion System program. From 1997 to 2001 he was supervisor of the Advanced Propulsion Group at JPL. He now manages JPL’s high power EP tasks and is the Deputy Ion Propulsion Sys‐ tem Lead for the Advanced EP System for the Lunar Gateway. He has authored over 100 papers and has received 7 best paper awards at the Intl. EP Conference and the Joint Propulsion Conference.