Station Explorer for X-ray Timing and Navigation Technology (SEXTANT)

NASA has invented a new type of autonomous space navigation that could see human-made spacecraft heading into the far reaches of the Solar System, and even farther – by using pulsars as guide stars. It’s called Station Explorer for X-ray Timing and Navigation Technology, or SEXTANT (named after an 18th century nautical navigation instrument), and it uses X-ray technology to see millisecond pulsars, using them much like a GPS uses satellites

How it works?

• Pulsars are highly magnetised, rapidly rotating neutron stars – the result of a massive star’s core collapsing and subsequently exploding.
• As they spin, they emit electromagnetic radiation. If an observer is in the right position, they can appear as sweeping beams, like a cosmic lighthouse.
• They’re also extraordinarily regular – in the case of some millisecond pulsars, which can spin hundreds of times a second, their regularity can rival that of atomic clocks.

This is what led to the idea behind SEXTANT. Because these pulsars are so regular, and because they’re fixed in position in the cosmos, they can be used in the same way that a global positioning system uses atomic clocks.