The Titan Corporation conducted a systems engineering study to develop an overall architecture that meets both the articulated and unarticulated requirements on the Prometheus Program with the least development effort. Key elements of the Titan‐designed ENABLER system include a thermal fission reactor, thermionic power converters, sodium heat pipes, ion thruster engines, and a radiation shield and deployable truss to protect the payload. The overall design is scaleable over a wide range of power requirements from 10s of kilowatts to 10s of megawatts. © 2004 American Institute of Physics