Timekeeping is a critical component for a wide array of technologies from high-frequency trading to space navigation. Space-based applications place some of the most stringent requirements on timekeeping, requiring exceptional performance in harsh environments while at the same time maintaining low size, weight, and power requirements. The next major advancement in timekeeping for space applications is via the successful demonstration of space-based optical atomic clocks, and ESA is pioneering this. The goal is to successfully demonstrate a strontium optical atomic clock, which uses an optical transition at 698 nm as a clock reference and another narrow linewidth transition at 689nm for laser cooling. To probe the 689 nm transitions, a laser with a linewidth of ≈ 1 kHz is needed. These performance requirements can be met with large laboratory-scale devices. However, these systems suffer from large size weight and power. This project offers a solution to these problems by providing A discrete mode diode laser stabilized to an optical microresonator achieving kilohertz level linewidth with low size weight and power.