The COMPASSO mission and its iodine clock

Abstract

High-precision clock technologies have a variety of applications both in lab environments and in space, such as research of geodesy, relativity theory and also navigation with the GNSS network. However, the established clock technologies in space (rubidium standards and masers) lack in precision and long-term stability, limiting the accuracy of space research and navigation. Optical clocks have the potential to improve the performance by orders of magnitude, hence offering unprecedented accuracy in numerous fields of research and high-precision navigation [1]. The DLR COMPASSO mission will demonstrate the first optical clock technology in orbit and will be installed on the BARTOLOMEO platform of the ISS with a scheduled launch in 2025. In this contribution, we will present the mission architecture and highlight the features of the ruggedized clock technology [2], which utilizes modulation transfer spectroscopy in molecular iodine yielding a long-term fractional stability of up to 10−15. [1] Schuldt, T. et al. GPS Solut. 25, 83 (2021). [2] Schuldt, T. et al. Appl. Opt. 56, 4, (2017).