This paper describes a systemic approach to co-design of collaborative museums, using ethnography, co-creation workshops and fast prototyping, amongst other Social Science and Human Centered Design methods. Focused on the creation of immersive and collaborative museum experiences, it provides a rationale for involving carefully selected multidisciplinary teams and users in the entire design cycle, and presents a process that supports this task, from research to development, pointing its value and limitations. In order to bring the discussion into context and exemplify the use of a group of methods that can support collaborative design, it introduces the case of a Brazilian Planetarium and Science Museum.