Active X-ray Optics for Astronomy

Active optics utilize an actuated element to improve the performance of a telescope. While active optics are now routinely used in large, ground-based optical telescopes, a nascent application of this technology is in the correction of thin, grazing-incidence X-ray astronomical telescopes. In this chapter, we discuss the benefits of using active X-ray optics, such as figure control, adjusting optics during mounting and alignment, and possibility of switching between different optical prescriptions in-flight. We review active X-ray optics technologies as applied to either segmented or full-shell X-ray mirrors in light of the current state of the field. Finally, we offer a general synopsis of how to implement corrections on an X-ray telescope, starting with understanding of how to model a deformable X-ray mirror and ending with the correctability analysis of an active optics’ design. We also cover active optics in the context of previously explored mission concepts and discuss future milestones in the application of active X-ray optics for astronomy.