NASA EPSCoR: A Modular Electrical Power System Architecture for Small Spacecraft

Small satellites are growing increasingly popular with the aerospace community for gathering data in a space environment because of their compact form and the numerous launch opportunities available. Most small satellites use subsystems such as a Command and Data Handling system, an Attitude Determination and Control System, and an Electrical Power System. These satellite subsystems are either designed in-house or purchased as a premade package off-the-shelf. This work focuses on the Electrical Power System. Whether pre-made or custom, the electrical power system typically uses a monolithic, centralized architecture. However, this system architecture, while able to be used on many small satellites, may not always be operating in its maximum efficiency range, which is detrimental to a small satellite's power budget. The main goal of this proposal is to create a reusable and scalable power system for a wide variety of missions while keeping efficiency at a maximum and redesigning for each new mission at a minimum. Reusability is achieved by basing the design on common building blocks or "modules" where the same modules can be used from mission to mission. Scalability is achieved by not limiting the number of modules that can be connected together-more modules can be added to the system as dictated by the mission power needs. In this system, solar arrays and battery units connect directly to the power bus, supplying a common, unregulated voltage to each subsystem. These subsystems then regulate the bus voltage to their individual power needs. The power system also features direct energy transfer and allows for both battery charging/discharging and solar-only operation. To reach our goal, we propose to design and test a reusable and scalable electrical power system for the small satellite KySat-3.