The Aerospace Corporation has a long history of supporting US timekeeping through atomic clock research and timekeeping systems engineering. The Physical Sciences Laboratories are home to clock testbeds, simulations, and subject matter experts who focus on basic atomic physics in support of critical space technologies for RF and optical communications and GNSS such as GPS. Commercial space systems rely on advanced clock technology to enable high performance communication and positioning technologies. Clock stability in space significantly impacts reliability and performance of space-based navigation signals. Our fundamental research investigations directly impact these technologies required for past, present, and future space missions. Our laboratories have historically provided consultation and expertise on clock technologies to the Space and Missile Systems Center, now Space Systems Command, and other customers in the US government in support of the advancement of timing technology for space. In this presentation, we share an overview of our laboratory’s basic physics research capabilities and their impact on space systems as they apply to timekeeping. Several clock physics and clock technology investigations will be addressed and described in context with satellite-based timekeeping, which supports present and future space missions. Many of our plans involve investigation of atomic physics issues that influence space clock performance and SWaP, and prioritize issues not addressed in academic and industrial laboratories. From chip-scale atomic clock technologies to next generation high performance space clocks, we operate testbeds and perform laboratory investigations to promote improved reliability and manufacturing capabilities.