We report on a longitudinal study of the emergence of the ATLAS detector, a complex technological system developed at CERN, Geneva. Our data show that the coordination of initial architectural choices was driven by cycles of contestation and justification that resulted in the creation of what we term interlaced knowledge-pockets of shared knowledge interwoven within and across subsystem communities at ATLAS. We also found that these justifications were possible because of the presence of a boundary infrastructure that served as a common substrate of knowledge for all ATLAS participants. Together, the boundary infrastructure and interlaced knowledge enabled participants to make co-oriented technological choices, address latent interdependencies, and minimize the incidence and severity of glitches when integrating the various subsystems.
