Recently, radiation-hardened SRAM-based field programmable gate arrays (FPGAs) and radiation-hardened flash-based FPGAs have been used frequently for space systems. The total-ionizing-dose tolerances of such radiation-hardened FPGAs are limited to a 1 Mrad total-ionizing-dose. Therefore, space embedded systems must be surrounded by heavy shielding material. However, if a shield-less space embedded system could be achieved, then rocket launch costs could be decreased. This paper therefore presents a proposal of a new radiation-hardened optically reconfigured gate array exploiting its parallel configuration. The total-ionizing-dose tolerance of the radiation-hardened optically reconfiguration gate array has been measured experimentally as a 406 Mrad total-ionizing-dose using a cobalt 60 gamma radiation source, demonstrating at least 406 times higher radiation tolerance than those of currently available radiation-hardened FPGAs.