For centuries, sailors used the night sky to navigate the seas. But once humanity makes the transition to travel and live in space, the equation changes. That is why scientists aboard the International Space Station are looking for a GPS alternative to travel to deep space.
Rather than relying on satellite constellations, scientists propose that we use neutron stars, or the dead remnants of stars that exploded in a supernova, as “cosmic lighthouses,” according to a new NASA statement.
More specifically, scientists are looking at pulsars, fast-spinning neutron stars that emit X-rays in narrow spinning beams, like a lighthouse.
A washing machine-sized X-ray telescope called NICER (Neutron Star Interior Composition Explorer) connected to the outside of the space station is already creating a GPS-like map of neutron stars.
The idea of using this map as a way of navigating has been called “XNAV” in the past and could allow autonomous spacecraft to travel through space while knowing exactly where they are going.
“The GPS uses precisely synchronized signals. The pulsations of some neutron stars are very stable, some even as stable as long-term Earth atomic clocks, making them potentially useful in a similar way, “said Luke Winternitz, a researcher at NASA’s Goddard Space Flight Center, in the statement.
Other approaches, like NASA’s Deep Space Atomic Clock (DSAC), could also one day act as a GPS for deep space by measuring how long it takes for information to bounce from node to node, down to the nanosecond.
The neutron star approach, however, uses distant celestial objects as a way to self-locate, not atomic clocks.
The concept has already shown promise. In 2018, scientists already demonstrated that such a pulsar-based navigation system is functional on board the space station. The experiment called SEXTANT (Station Explorer for X-Ray Navigation and Synchronization Technology) could determine the location of an object moving thousands of miles per hour through space.
“It effectively converts the ‘G’ in GPS from Global to Galactic,” Jason Mitchell, director of NASA’s Advanced Communications and Navigation Technology Division, said in the statement. “It could work anywhere in the solar system and even transport robotic or manned systems beyond the solar system.”
But as of now, the technology behind such a conceptual galactic GPS is still quite bulky. Mitchell claims that future XNAV devices could be cut. “For example, it would be interesting to place an XNAV telescope on a small satellite that could independently navigate the asteroid belt and characterize the primitive bodies of the solar system.”
As for now? NASA scientists are discovering whether such a navigation system could assist NASA’s planned Lunar Gateway station to launch future trips to Mars.
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