Electric power supply (EPS) is the heart of any aerospace mission and plays an important role in improving the performance and service lifetime of spacecraft. It generates, converts, stores, and distributes power to different voltage levels. The EPS is composed of solar panels, a power conditioning unit (PCU), batteries, and a power distribution unit (PDU). This paper describes the design and analysis of an efficient power conditioning system for a CubeSat standard small satellite. For this purpose, the aim of this paper is to propose a two-input maximum power point tracker (MPPT)-based interleaved boost converter. The design copes with the fact that when a satellite revolves around the Earth, a single panel or at most two panels face solar radiation at different angles. In order to extract maximum power from the panels, the designed converter drives the solar panels at the maximum power point (MPP). A small signal model is drawn for the converter, and the closed-loop gain of the converter is analyzed using a Bode diagram. To improve the phase margin and gain, a PID compensator is designed and added to the closed loop of the converter. Finally, the performance of the proposed converter is validated by the simulation results.