In September 2015, NASA selected five mission concepts from a field of 27 to proceed to the next stage (step 2) of the latest Discovery mission competition. Each team will submit a Mission Concept Study to NASA in August 2016, and up to two missions are expected to be selected for flight in December 2016. This paper describes Psyche, a unique investigation of a metal world, which is the only one of the selected mission concepts that would use electric propulsion to accomplish its mission objectives. Psyche would apply commercially developed electric propulsion and space power systems with strong system-level heritage to accomplish a deep space NASA science mission at comparatively low technical-risk and cost-risk. This paper describes the Psyche mission concept and the unique SEP (solar power-electric propulsion) architecture that allows the use of Space Systems/Loral’s commercial SPT-140 Hall thruster propulsion system at solar distances of up to 3.3 AU with only minimal modifications. Building on previous work analyzing SEP systems for Discovery-class missions, this paper describes the heritage, design and testing which have been conducted on the power and propulsion systems to develop the Psyche mission concept, addresses the differences between GEO and deep-space environments, and describes actions taken to ensure that GEO heritage systems can be operated reliably in deep-space.