A radiation-tolerant flash-based FPGA switching element includes a plurality of memory cells each having a memory transistor and a switch transistor sharing a floating gate. Four such memory cells are combined such that two sets of two switch transistors are wired in series and the two sets of series-wired switch transistors are also wired in parallel. The four memory transistors associated with the series-parallel combination of switch transistors are all programmed to the same on or off state. The series combination prevents an “on” radiation-hit fault to one of the floating gates from creating a false connection and the parallel combination prevents an “off” radiation-hit fault to one of the floating gates from creating a false open circuit.