Rad hard flash mem was used https://www.militaryaerospace.com/computers/article/16726640/cubesat-designers-choose-radiationhardened-nand-flash-memory-from-ddc-for-nasa-biosentinel-space-project

ARM-board, reference for rad hard https://www.mouser.com/new/vorago-technologies/vorago-rh-obc-1-board/