Recent years have seen a surge in hackathons – intensive design-sprint-like events in which participants do playful and exploratory programming and hacking on hardware and software over a weekend, 24 hours or a similar very intense and constrained timeframe. Hackathons hold great potential for learning about how people engage in developing technology, however, there is little research into the inner workings of a hackathon. We present the results from a study conducted by a Research through Design approach, in order to leverage the knowledge gained while engaged in the design process. We did this, by focusing on a detailed analysis of how a hackathon setting affected a team’s management of the design space, that is the conceptual space of opportunities and constraints emerging throughout a design process. Through our study we have identified four key factors that influenced the development of the design space. Specifically, we found that 1) the format, 2) the available tools and materials, 3) the participants’ domain knowledge, and 4) personal skills, particularly influenced the development of the design space.