Pulsars as Natural Oscillators for Long-Term Deep-Space Missions

<title>Abstract</title> Pulsars are spinning neutron stars that emit highly stable, periodic signals with periods on the order of milliseconds to seconds. This natural stability makes pulsars promising for forming an independent timing system for spacecraft navigation, especially in deep space. The North American Nanohertz Observatory for Gravitational Waves team has released 15 years of data for 68 millisecond pulsars. We analyze the stability of these pulsars and estimate their range positioning accuracy for autonomous navigation. Several pulsars enable sub-kilometer accuracy over averaging periods of 100 days to more than 15 years. We also demonstrate the feasibility of an onboard pulsar ensemble using a classical weighted algorithm, achieving stability levels of 10⁻¹⁶ over 10 years or more. Currently, no space-based atomic clock can provide these levels of stability over a 10-year period. Therefore, the exceptional natural stability of pulsars could be leveraged for deep-space missions. In addition, pulsars have extremely long lifespans, offering unprecedented reliability for space missions.