The traditional CubeSats development model is a one-off build designed to accomplish a specific mission using proprietary hardware and software. The specific mission requirements and associated development costs result in a lack of reproducibility for CubeSats. The Naval Academy Standard Bus (NASB) advances the concept of CubeSat modularity with a design that physically separates a fully-functional standalone 1U bus from an independently-developed 1U or 2U customer payload module with a 10-pin wiring harness serving as the sole electrical interface between bus and payload modules. Residing within the standard bus module the main onboard computer (OBC) handles uplink and downlink communications and connects the NASB to the payload module through two interface boards: the Bus Board and the Payload Interface Board (PIB). Ground commands received by the NASB pass through the Bus Board to the PIB in the payload module, through which they are communicated to the payload via universal asynchronous receiver/transmitter (UART) protocol. Messages and stored data generated by the payloads are stored on a secure digital card within the PIB, to be passed on to NASB and downlinked to the ground station. This modular design allows for independent development of payloads, shortening CubeSat development timeline by eliminating the need for bus development in parallel with payload development.