Frequency multiplexed readout systems for large TES bolometer arrays are in use for ground and balloonbased mm-wavelength telescopes. New digital backend electronics for these systems implement advanced signal processing algorithms on FPGAs. Future satellite instruments will likely use similar technology. We address the challenges of operating FPGAs in an orbital radiation environment using neighbour-neighbour monitoring, where each FPGA monitors its neighbour and can correct errors due to radiation events. This approach reduces the FPGA's susceptibility to crippling events without relying on triple redundancy or radiation-hardened parts, which raise the system cost, power budget, and complexity. This approach also permits earlier adoption of the latest FPGAs, since radiation-hardened variants typically lag the state of the art.