NASA’s Got a Plan for a ‘Galactic Positioning System’ to Save Astronauts Lost in Space

Your phone’s GPS works fast, but Arzoumian said the galactic positioning system would work slower —taking the time needed to traverse long stretches of deep space. It would be a small, swivel-mounted X-ray telescope, which would look a lot like the big, bulky NICER stripped down to its barest minimum components. One after another, it would point at at least four millisecond pulsars, timing their X-ray ‘ticks’ like a GPS times the ticks of satellites.

Three of those pulsars would tell the spacecraft its position in space, while the fourth would calibrate its internal clock to make sure it was measuring the others properly.

Source: livescience.com