Transforming Outdoor Places into Learning Spaces is a 4-year design-based research project, funded by the National Science Foundation, that investigates how rural families learn in outdoor places when engaging in mobile learning experiences. Our research transforms the everyday outdoor places visited by rural families into child-centered learning spaces. Rural communities are underserved by indoor museums; however, they are places rich with outdoor trails, parks, and forestlands. SPACES (Supporting Place-based Augmented Contexts for Engaging Science) is a GPS and augmented reality system that adds virtual content to outdoor spaces without ruining the aesthetic experience of being in the outdoors. SPACES partners include rural libraries, outdoor learning centers, and university researchers. Our objectives are to (1) build knowledge for the informal STEM education field by conducting three iterations of design-based research study investigating how rural families learn about science in their community and (2) have a strategic impact on outdoor education practice with the contribution of empirically-vetted design conjectures for place-based mobile computing to support participatory family science learning.