Designing compact X-ray optics for Pulsar-Informed Navigation

This is a study of pulsars and X-ray optics in order to design a practical telescope for Pulsar-Informed Navigation (PIN). Measurements made with the Neutron star Interior Composition Explorer (NICER) telescope during the Station Explorer for X-ray Timing and Navigation Technology (SEXTANT) program in 2017 successfully demonstrated PIN. However, the NICER telescope is too large to be accommodated as a navigation aid onboard other missions. Compact X-ray telescopes for PIN ideally maintain or improve on NICER's effective area and sensitivity to pulsed X-ray emission and reduce the focal length of the optics. The SEXTANT demonstration achieved better navigation accuracy than estimated by my application of a third-party theory. The NICER-SEXTANT team had accounted for the high fraction of emission occurring in the soft X-ray band from 0.3 to 2.0 keV. It is possible to design optics for the soft X-ray emission characteristics of a few millisecond pulsars, enhancing the signal from these pulsars. This thesis introduces pulsar astronomy and X-ray optics, then outlines my program of research for a doctoral thesis. I describe adapting NASA GSFC HEAsoft tools for phase-resolved spectroscopy to search the 0.3 to 4 keV energy band to find the largest signal to noise ratio for a collection of bright millisecond pulsars. I then describe designing multilayer coatings to maximize the reflect efficiency in the soft X-ray bands, and an optical geometry with large grazing angles to shorten the focal length. Finally, I discuss translating this optical prescription into an instrument design and prototyping a segmented optical assembly to resolve challenges in mirror substrate fabrication for a PIN instrument system.