This document discusses applying tangible user interfaces (TUIs) to space systems concurrent engineering (CE) concept studies sessions. It proposes using physical TUI artifacts to represent models that multidisciplinary engineering teams currently manipulate digitally. The document reviews how teams currently collaborate using predominantly screen-based tools, and analyzes collaborative behaviors and model types used in CE sessions. It then presents the concept of TUIs and a taxonomy for classifying their elements and interactions. Finally, the document proposes a proof-of-concept TUI design for CE sessions involving physical artifact representations of models that team members can directly manipulate.