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A Systems Engineering Tool for Small Satellite Design

The growing popularity of small satellites for applications of all kinds has lead to a marked increase in the number of requests from customers of The Aerospace Corporation for studies involving small satellites. The existing design tools used by the Corporation for concept evaluation of large spacecraft have, in many cases, proven inadequate for these small spacecraft studies. As a result, Aerospace is developing a systems engineering tool to support the conceptual design of small satellites. The Aerospace Corporation’s small satellite systems engineering tool utilizes a spreadsheet-based approach to efficiently track information regarding the mass, power, and volume of the satellite subsystems. This subsystem information is derived through a variety of means, including analytical relationships, iterative solvers, and databases of components appropriate for small satellites. Physics based models for such factors as solar illumination and external torques have been incorporated into the tool to aid in the analysis of the design. In addition to data tracking, the spreadsheet approach used makes it easier for a concurrent engineering methodology to be applied to the design process. This means the effects of a change in one subsystem are immediately propagated to the other subsystems, and system-level effects are more easily identified. The end result is a tool that facilitates rapid systems-level concept evaluation and trade-space exploration in support of the small satellite design process. This paper describes The Aerospace Corporation’s small satellite systems engineering tool. The approach underlying the tool, as well as an overview of the implementation, relationships between the subsystems, and the flow of information are presented. Introduction A growing number of future space missions, for either programmatic or technical reasons, require small, lowmass, low-cost satellites. Interest in these new mission concepts is encouraged by the perception that a small satellite can be both capable and low-cost. As a result, more small satellites are being formally studied at the conceptual stage of many civil, commercial, and military programs than have been in the past. Figure 1 clearly illustrates the impressive growth in the number of small satellites launched over the last two decades, particularly at the smaller (<25kg) end of the size spectrum. Both civil and military space programs have launched research and development efforts focused on small satellites. Examples include NASA’s Space Technology 5 Nanosat Constellation Trailblazer, and the Air Force Research Laboratory’s Technology Satellite of the 21st Century (TechSat 21) and MightySat programs, which seek to test and prove technologies and architectures. Further advances in small satellite capabilities are being driven by research into new technologies such as microelectromechanical systems (MEMS). For example, The Aerospace Corporation’s Center for Microtechnology is