Feasibility and performance assessment of a practical autonomous deep space navigation system based on X-ray pulsar timing

TL;DR

This paper evaluates the practicality and performance of an X-ray pulsar-based deep space navigation system, considering real-world constraints and potential technological implementations, including the use of existing instruments like MIXS.

Contribution

It provides a feasibility analysis of implementing X-ray pulsar navigation with practical spacecraft instruments, highlighting potential designs and challenges for operational systems.

Findings

Navigation uncertainties depend on pulsar selection and strategy.

Using existing instruments like MIXS is feasible for XNAV.

Design challenges include optics simplification and system integration.

Abstract

Shemar et al. (2016) presented results based on the output of a feasibility study for the European Space Agency (ESA) on the use of X-ray pulsars for deep space navigation, a concept often referred to as 'XNAV'. Here we describe some of the key results as well as providing additional information which includes navigation uncertainties and the potential X-ray technology that could be used. For a conventional deep space mission, an X-ray navigation system must be practical to implement as a spacecraft subsystem and to this end it must meet restrictive mass, volume and power consumption requirements. The implementation of an X-ray observatory sized instrument is unrealistic in this case. The Mercury Imaging X-ray Spectrometer (MIXS) instrument, due to be launched on the ESA/JAXA BepiColombo mission to Mercury in 2018, is an example of an instrument that may be further developed as a practical telescope for XNAV. Simulations involving different pulsar combinations and navigation strategies are used to estimate the navigation uncertainties that may be achievable using such an instrument. Possible options for future developments in terms of simpler, lower-cost Kirkpatrick-Baez optics are discussed, in addition to the principal design and development challenges that must be addressed in order to realise an operational XNAV system.