Designing compact X-ray telescopes for interplanetary navigation

Jacob Payne; University of Iowa

This presentation begins with a comparison of predicted and experimental performance for pulsar timing as a method of coarse navigation. Experimental results from the 2018 demonstration called the Station Explorer for X-ray Timing and Navigation Technology (SEXTANT) using the Neutron star Interior Composition ExploreR (NICER) telescope on the International Space Station provide a navigation estimate that stabilizes with ±30 km (3σ) accuracy within 24 hours of starting measurements window, which is less than ±50 km (1σ) accuracy predicted by earlier theory. Improved measurement accuracy is consistent with high pulsed fractions and pulsed flux in the soft X-ray band (0.3 to 4 keV). An implementation of a compact instrument optimized for soft X-ray measurements for application to interplanetary missions is presented to alleviate and complement Deep Space Network ranging.