The space agency is preparing to test the use of pulsars as navigational beacons, which it hopes will enable a sustained human presence throughout the solar system.
hen the first pulsar was discovered in 1961, scientists were astonished at the precise, regular signals emanating from the celestial object, which from Earth can look like a flickering star. It was lightheartedly given the designation LGM-1, which stood for “Little Green Men.” Perhaps extraterrestrial life had put the pulsar out there as some sort of beacon or lighthouse, some speculated.
“We did not really believe that we had picked up signals from another civilization,” said co-discoverer Jocelyn Bell Burnell in a speech years after the discovery, according to Popular Science, “but obviously the idea had crossed our minds and we had no proof that it was an entirely natural radio emission.”
Today, we know that pulsars are naturally occurring, incredibly dense neutron stars that result after a living star exhausts its energy and collapses. They rotate quickly while emitting beams of electromagnetic radiation, creating the illusion of a steady pulse.
Now, in an odd twist, we humans are looking at using pulsars as navigational beacons after all. A new NASA instrument is scheduled to launch on SpaceX’s Dragon CRS-11 mission on Saturday (June 3) that will, in part, test to see if pulsars are a good way of enabling deep-space navigation.
Nasa’s Station Explorer for X-ray Timing and Navigation Technology project (SEXTANT), the agency says, “will demonstrate a GPS-like absolute position determination capability by observing millisecond pulsars, which will enable autonomous navigation throughout the solar system and beyond.”
The second ingredient is the SEXTANT software on NICER, which can measure changes in the arrival time of these pulsar emissions as the ISS orbits. The goal is to see if SEXTANT’s measurements of the space station’s orbit mirror the actual orbit of the space station. If they match, the navigational concept could work in deep space.
NASA is hoping to send astronauts to the Mars in the 2030s, and recently announced a small space station at the moon as a stepping stone for that ambition. This “deep space gateway,” as NASA calls it, would include “a power bus, a small habitat to extend crew time, docking capability, an airlock, and… logistics modules to enable research,” the agency announced earlier this year.
This space station would be the first phase of the gateway, while the second phase would involve a reusable deep-space transport spacecraft that could carry crews out to Mars. While we don’t know what kind of navigation this future Martian spacecraft would use, it’s possible that pulsars could help chart the way — depending on how well these NICER-SEXTANT tests go.