Clocks and oscillators have traditionally played an important role in space navigation and communication, as well as in space science and in tests of fundamental physical laws. Microwave clocks currently in use in space will be replaced by laser cooled clocks capable of significantly improved performance. Beyond this, lasers will play an important role as oscillators used for their spectral purity in interferometry based experiments, and will likely be used as the local oscillators for future optical clocks. In this paper a short review of the role of clocks and oscillators in space is presented, together with some future projections for laser based systems.
Brent C. Young,
"Clocks and oscillators in space", Proc. SPIE 4269, Laser Frequency Stabilization, Standards, Measurement, and Applications, (3 May 2001); doi: 10.1117/12.424467; https://doi.org/10.1117/12.424467