Physics: The next generation of atomic clocks in space

The first trapped-ion atomic clock to be operated in space, reported in Nature, is shown to outperform current space clocks. The level of performance indicates that this technology could be used to enable near-real-time navigation of deep space probes.

The atomic clocks currently used in space rely on atoms confined in a box to serve as a meter for the clock. The long-term stability of these clocks is hampered by the atoms colliding with the walls of the box. This effect is overcome in trapped-ion atomic clocks in which charged atoms are confined electromagnetically, thereby eliminating wall collisions.

In 2019, NASA launched a trapped-ion clock, named the Deep Space Atomic Clock, into orbit around Earth. Eric Burt and colleagues present data from the first operating year of this clock. Despite developing a fault shortly after testing began, its short- and long-term stability still exceeds that of current space clocks by up to ten times. Variations in radiation, temperature and magnetic fields did not seem to limit the performance of the clock, making it suitable for operation in the extreme environment of space.

The Deep Space Atomic Clock currently has a life expectancy of 3–5 years, but work is being done to extend this to 10 years or beyond, the authors note. Ongoing investigations and development of this technology could open up applications in one-way navigation for deep space exploration.