To be launched upon a SpaceX Falcon Heavy Rocket on June 22, 2019,
NASA's Deep Space Atomic Clock is designed to help navigating
through the solar system and to support science experiments.
Using mercury ions in electromagnetic traps, the clock is accurate to
within 1 second every 9 million years which is said to be fifty times more
accurate than the atomic clocks flown on the GPS constellation.
Story here :-
https://www.nasa.gov/feature/jpl/fiv...e-atomic-clock
Web site here :-
https://www.nasa.gov/mission_pages/tdm/clock/index.html
Videos here :-
https://www.nasa.gov/mission_pages/tdm/clock/index.html