Abstract: The LUVOIR team is conducting two full architecture studies. Architecture A – 15 meter telescope that folds up in an 8.4m SLS Block 2 shroud is nearly complete. Architecture B – 9.2 meter that uses an existing fairing size will begin study this Fall. This talk will summarize the ultra-stable architecture of the 15m segmented telescope including the basic requirements, the basic rationale for the architecture, the technologies employed, and the expected performance. This work builds on several…