The IEEE Time-Sensitive Network (TSN) provides a scalable solution for real-time communication using Ethernet technology. In this paper, we address the availability of FPGA-based TSN under a harsh radiation environment. In particular, the impact of periodic repair mechanisms and the transmission redundancy on the communication availability is investigated. To achieve our goal, we propose a Timed Automata (TA) model of the TSN to capture the impact of periodic repair on communication reliability. As a result, the proposed analysis framework allows the designer to set up the appropriate repair cycle and redundancy level according to the application criticality and required system reliability. To demonstrate the proposed analysis framework, we consider a case study based on the switched network deployed in the Orion Multi-Purpose Crew Vehicle (MPCV) American-European interplanetary spacecraft. Our analysis results show a specific optimal scrubbing rate for each radiation environment regardless the network utilization conditions.