Communication between satellites and mission control centers is currently protected via the Space Data Link Security (SDLS) Protocol. This protocol uses exclusively symmetric cryptography, which makes it resilient against quantum computers, but prevents key updates from achieving post-compromise security and limits operational efficiency, especially in future federated environments. To resolve these issues we designed a key-update/establishment protocol based on PQNoise that leverages KEMs to achieve confidentiality and authenticity. We prove the resulting scheme secure in a slightly modified version of the Bellare–Rogaway-model. To keep the SDLS protocol untouched, the resulting protocol is not used as the handshake phase of a larger data-transmission protocol, but actually run independently, permitting to start from shared keys.