Abstract: The power subsystem could possibly be the most under-appreciated and forgotten of all of the on-board electrical subsystems. There may be several reasons for this, but the most likely is that most people just don’t find the subject interesting enough. There are, of course, exceptions to this generalization, but it is safe to say that no one is currently planning a mission to demonstrate optimization of power system network. Grabbing the attention of spacecraft engineers are subjects like; more advanced communications systems, on-board data handling, and high speed data links, imaging systems, micro-propulsion, attitude control algorithms, sensors and actuators. It is natural that the best people in a small organization focus on the more exciting aspects of a mission; these subjects will typically be the differentiator of an organization’s space mission from that of the rest of the world. However, it is also clear that these systems need power, and power that is delivered reliably and efficiently.