Feasibility of phase stabilization for satellite-mediated twin-field quantum key distribution

Quantum key distribution (QKD) is critical for future proofed secure communication. Satellites will be necessary to mediate QKD on a global scale. The limitations of the existing quantum memory and repeater technology mean that twin-field QKD (TF-QKD) provides the most feasible near-term solution to perform QKD with an untrusted satellite. However, the TF-QKD requires links between ground stations and satellites to be phase stable. We show that phase stabilization of the links to LEO and MEO satellites is feasible in spite of phase noise due to atmospheric turbulence, laser instability, and path length asymmetry while only incurring a quantum bit error rate (QBER) penalty of less than 1.5%. These results are also applicable to future untrusted satellite networks employing precisely synchronized quantum memories or quantum repeaters.