Time & Time Transfer

Currently, microwave time transfer systems between ground and space reach a level of precision on the order of the nanosecond (about 1 to 30 ns achieved with GPS). An integration over ~30 days would be necessary to reach the 10⁻¹⁵ level. That cannot support the performance requirements and goals of future optical atomic clock in space missions (such as ESA-SOC), which aim for the 10⁻¹⁷ level or better.

Precise laser time- and frequency-transfer from the ground to an orbiting satellite would make it possible to improve upon the current state of the art in timing by roughly a factor of 1000, to the 1 ps level.

This would also enhance the performance of existing systems and provide unique capabilities in navigation, precise timing, earth sciences, and geodesy, and the same approach could provide a platform for testing fundamental physics in space.