Station Explorer for X-Ray Timing and Navigation (SEXTANT)


Develop capabilities that will enable sustained human presence throughout the solar system by using Pulsars for autonomous navigation.

X-ray navigation (XNAV) and X-ray communications (XCOM) are revolutionary concepts, as identified in the NASA technology roadmap, that will enable sustained human presence throughout the solar system, as well as enhance and enable science in the outer solar system and beyond. High bandwidth communications and advanced navigation capabilities will enable future deep space exploration of the solar system and pinpoint navigation in near-Earth space. The X-ray navigation (XNAV) and communications (XCOM) project elements will focus on the development of the X-ray based technologies capable of providing accurate autonomous navigation and high bandwidth communications, respectively, beyond the inner solar system. Technology test beds including those that utilize the ISS will be considered.


X-ray Navigation (XNAV): The Station Explorer for X-ray Timing and Navigation Technology (SEXTANT) will demonstrate a GPS-like absolute position determination capability by observing millisecond pulsars, which will enable autonomous navigation throughout the solar system and beyond.

X-ray Communications (XCOM): Exploit extremely low beam divergence of X-rays to provide high-rate deep-space, low transmit power, highly physically secure data links, and enable new penetrating communications capabilities. (XCOM is not part of the SEXTANT technology demonstration of XNAV.)

Principal Technologist: Project Manager:
Ron Litchford ( Jason Mitchell (

NASA’s NICER Does the Space Station Twist

This time-lapse video, obtained June 8, 2018, shows the precise choreography of NASA’s Neutron star Interior Composition Explorer (NICER) as it studies pulsars and other X-ray sources from its perch aboard the International Space Station.This video is public domain and can be downloaded, along with other versions from the Scientific Visualization Studio.Credits: NASA’s Goddard Space […]

NASA Team First to Demonstrate X-ray Navigation in Space

In a technology first, a team of NASA engineers has demonstrated fully autonomous X-ray navigation in space — a capability that could revolutionize NASA’s ability in the future to pilot robotic spacecraft to the far reaches of the solar system and beyond. The demonstration, which the team carried out with an experiment called Station Explorer […]

New NASA Mission to Study Mysterious Neutron Stars, Aid in Deep Space Navigation

Though we know neutron stars are small and extremely dense, there are still many aspects of these remnants of explosive deaths of other stars that we have yet to understand. NICER, a facility to be mounted on the outside of the International Space Station, seeks to find the answers to some of the questions still […]

Close-up View of Neutron Star Mission’s X-Ray Concentrator Optics

A new NASA mission, the Neutron Star Interior Composition Explorer (NICER), is headed for the International Space Station next month to observe one of the strangest observable objects in the universe. Launching aboard SpaceX’s CRS-11 commercial resupply mission, NICER will be installed aboard the orbiting laboratory as the first mission dedicated to studying neutron stars, […]

X-Rays: Next-Gen Way to Travel and Talk in Space?

NASA scientists say they have figured out a way to use X-rays to both communicate with long-distance spacecraft, as well as navigate as they sail past the outer limits of the solar system. They say that using X-rays is faster than existing radio wave communications, can carry more information and won’t be blocked when spacecraft […]

NASA Taps the Power of Zombie Stars in Two-in-One Instrument

Neutron stars have been called the zombies of the cosmos. They shine even though they’re technically dead, occasionally feeding on neighboring stars if they venture too close. Interestingly, these unusual objects, born when a massive star extinguishes its fuel and collapses under its own gravity, also may help future space travelers navigate to Mars and […]


 n April 15, 2010, the President challenged NASA to “break through the barriers” to enable the “first-ever crewed missions beyond the Moon into deep space” by 2025. One of these barriers is navigation technology.In the 18th century, the advancement of clock technology and resulting improvement in navigation fidelity brought us to the New World that we now […]