Advancements in rigid body sensing and control for large, ultra-stable segmented apertures

BAE Systems Space & Mission Systems has led a series of NASA-funded programs under the Ultra-stable Large Telescope Research and Analysis (ULTRA) umbrella performing research and development of key technologies for NASA’s Habitable Worlds Observatory (HWO). One of the highest priority technology gaps for the HWO architecture is limiting the rigid body motion of the telescope optics to achieve the demanding wavefront stability needed by the coronagraph. Thus, a major focus of the current ULTRA program is building a subscale, three segment testbed to demonstrate segment level sensing and control to technology readiness level 4/5 at the fidelity needed for HWO. This paper will discuss component technologies, specifically picometer capable actuators and capacitive sensors, and the status of the multiple-segment testbed that is currently in assembly at BAE Systems SMS in preparation for testing at the Goddard Ultrastable Laboratory in the summer of 2026.