Flight model of the calibration source NI-CU before integration into NISP. Two supply harnesses can be seen, feeding the nominal and redundant side, respectively, of NI-CU with each five LEDs emitting at different wavelengths. Inside the base any LED illuminates the same PTFE reflector patch that in turn directly illuminates the FPA, with a field shaped by a set of five baffles, the last one visible at the top. The full NI-CU height is approximately 150 mm.