A Little Space Navigation Desiderata

Navigating in space apparently requires exploiting gravity of solar system objects to save on fuel. The direct line, or curving line/tensor to meet moving objects like planets is different than just finding out where one is. N.A.S.A. is trying traditional sextants on the space station and they also have a program called SEXTANT that uses pulsars for navigation. 

https://www.sciencealert.com/x-ray-pulsar-space…

https://scienceandtechnology.jpl.nasa.gov/…/deep-space…