John held positions at Hughes Research Labs, the Boeing Electron Dynamics Division, and the Electric Propulsion Laboratory, Inc., for 11 years prior to coming to CSU in 2002 to become the director of the Center for Electric Propulsion and Plasma Engineering. His current research interests include advanced diagnostics systems for evaluation of the plasmas created within EP devices and in the plumes downstream of the devices, miniaturized ion and Hall thrusters, instant start hollow cathodes, and materials and fabrication techniques that reduce the cost of EP systems. One particularly exciting recent interest is an ongoing investigation of how hollow cathode components in EP systems can be used to 3D print structures from metal powders.