Research Software Engineering (RSE) projects are increasingly used by nearly all disciplines to further scholarly work. Yet little is known, empirically speaking, about the quantity, quality, and scope, of these projects, nor how they change and mature over time. We present MARS, a software platform for Mapping and Analyzing Research Software, that serves as a discovery and inventory system for software projects at universities and research institutions across the United States. Creating this platform allows us to answer research questions like, "Just how many RSE projects are out there?", "What do they look like?", "How can we learn from these projects to accelerate new software projects in science?". This presentation demonstrates the current state of our in-progress development of the MARS platform.
