Galactic GPS: scientists began using pulsars as “space beacons”

For centuries, lighthouses have helped sailors navigate safely to the harbor. Their lights swept through the water, piercing fog and darkness, guiding sailors around dangerous obstacles, and keeping them on the right track. In the future, space researchers can get similar landmarks from stable signals created by pulsars, NASA reports.

Scientists and engineers use the International Space Station to develop pulsar-based navigation. They plan to create space beacons to help with space orientation, such as traveling to the moon through NASA’s Artemis program or in future manned missions to Mars.

Pulsars, or rapidly rotating neutron stars, are extremely dense remnants of stars that exploded like supernovae. They emit x-ray photons in bright, narrow beams that soar into the sky like a lighthouse when the stars rotate. From a great distance they seem to be pulsating, hence the name pulsars.

An X-ray telescope on the outer side of the ISS, a researcher of the internal composition of a neutron star or NICER, collects and marks the time of arrival of X-ray light from neutron stars across the sky. Software built into NICER, called Station Explorer for X-ray Timing and Navigation Technology or SEXTANT, uses pulsar beacons to create a GPS-like system. This concept can provide autonomous navigation throughout the solar system and beyond.

GPS uses precisely synchronized signals. The pulsations from some neutron stars are very stable, and some are even as stable as the Earth’s atomic clock. In the long run, this makes them potentially useful in a similar way.

Luke Vinternitz, NASA

The stability of pulses allows us to accurately predict the time of their arrival at any control point in the solar system. Scientists have developed detailed models that accurately predict when momentum reaches, for example, Earth. The time the pulse arrives at the detector on the spacecraft and comparing it with the expected achievement of the control point provides information for navigation far beyond our planet.

NASA noted that the navigation information provided by pulsars does not deteriorate when moving away from the Earth, as pulsars propagate throughout our galaxy.

“Galactic” GPS can work anywhere in the solar system and even carry robotic or controllable systems beyond.