This study sought to provide in-depth insight about the complex interaction of factors influencing motivations for sharing and re-using open research data within a single discipline, namely astrophysics. We identified the following research questions. 1. What discipline-specific characteristics influence motivation for sharing and re-using open research data? 2. What factors influence researcher’s motivations to openly share their data? 3. What factors influence researcher’s motivations to re-use open research data shared by others? 4. How can researchers in disciplines with low rates of open data sharing and re-use be encouraged to share and re-use more? These research questions are addressed through a case study consisting of nine in-depth interviews with astrophysics researchers and through observations of researchers in this discipline. With permission of the interviewees, all interviews were recorded, and these recordings were transcribed. The checked transcripts were imported into the ATLAS.ti software. ATLAS.TI software was used for open, axial, and selective coding.