Pulsars: Cosmic Lighthouses

• 21 Jul 2020

• Just as lighthouses have helped sailors navigate safely into harbor for centuries, future space travellers may receive similar guidance from the steady signals created by pulsars.
• Scientists and engineers are using the International Space Station to develop pulsar-based navigation using these cosmic lighthouses to assist with wayfinding on trips to the Moon under NASA’s Artemis programme and on future human missions to Mars.
• Pulsars, or rapidly spinning neutron stars, are the extremely dense remains of stars that exploded as supernovas. They emit X-ray photons in bright, narrow beams that sweep the sky like a lighthouse as the stars spin.
• An X-ray telescope on the exterior of the space station, the Neutron star Interior Composition Explorer or NICER, collects and timestamps the arrival of X-ray light from neutron stars across the sky.
• Software embedded in NICER, called the Station Explorer for X-ray Timing and Navigation Technology or SEXTANT is using the beacons from pulsars to create a GPS-like system.
• This concept, often referred to as XNAV, could provide autonomous navigation throughout the solar system and beyond.
• The stability of the pulses allows highly accurate predictions of their time of arrival to any reference point in the solar system.
• Navigation information provided by pulsars does not degrade by moving away from Earth since pulsars are distributed throughout our Milky Way galaxy.