Securing the Space Data Link Communication Protocol of Earth Observation Satellites

Earth Observation Satellites (EOS) as any remote unmanned vehicle need to communicate with its control ground station (CGS) either to send its housekeeping and payload telemetry data or to receive control commands and this is done through simple lightweight communication protocols which are designed taking into account the special conditions of the space environment. For civilian missions, this communication protocol is not protected and has several security issues that result in critical risks and safety concerns. In this paper, we studied the security vulnerabilities of space data link communication protocols and investigate the applicability of software-based solution to secure these communication protocols that adopt a software-friendly cryptographic algorithm to ensure the protection of exchanged data between the EOS and its CGS to reduce the penalties of added hardware device which affects negatively the spacecraft resources power consumption volume and mass. For validation, a software spacecraft simulator developed to evaluate the impact of different cryptographic algorithms on the space link security protocol. The results showed that ChaCha-poly1305 is a good candidate as authenticated-encryption algorithms used to secure space data link protocol (SDLP) to guarantee its messages confidentiality and authentication, without affecting the resources of the spacecraft.