Applying a Model-Based Approach to Develop a Standardized Template for CubeSat-class Satellites

CubeSats have most commonly been used by students and researchers as a cost effective means of accessing space. As demand grows for more complex space systems, however, the complexity and capability of CubeSat systems must also increase. One drawback of increased complexity is the increase in obscurity of how a change in one area of the design propagates through the rest of the system. Dealing with this added complexity takes away from student education experiences while also increasing the design cycle time, taking CubeSats further away from the key characteristic advantages that define them. One solution to this is to apply Model-Based Systems Engineering (MBSE) methodology to CubeSats, providing a standardized template that the developers can use to make the design cycle more efficient. Lately, the practice of MBSE has become increasingly nuanced and advances have focused on the application of tools and practices to aid in the development of space systems. This includes efforts concerned with the development and description of CubeSats. Most recently, the development of the CubeSat System Reference Model (CSRM) by the International Council on Systems Engineering (INCOSE) Space Systems Working Group (SSWG) has better enabled the description of CubeSat systems using common modelling language. At the U.S. Naval Academy (USNA), the Small Satellite Program has been developing and launching student-built project satellites since 2001 and CubeSats since 2012. Given the time constraints and minimal funding of an undergraduate education program, the need for a simple build template for CubeSats was recognized and the PSAT1U system was conceived. PSAT1U is a 1U CubeSat designed to be utilized as a modular architecture with easily accessible parts allowing students to focus on designing and implementing their on-board payload and mission systems without spending more time carrying out trade studies on well understood subsystems and components. The USNA has used the CSRM along with documentation from the development of PSAT1U to create a Model-Based representation of the PSAT1U system. The aim of this model is to aid in the education of undergraduate engineering students in their capstone design course as well as to reduce design and development times for future CubeSat systems. This paper will present an overview and description of the PSAT1U model, outline the design of the physical system as well as the development of the MBSE model and discuss its implementation in a classroom setting as well its potential role in the development of future systems. Finally, the propagation of system changes through the model will be demonstrated to illustrate the utility of describing a CubeSat system this way.