diff --git a/src/main/sensor_mod.F90 b/src/main/sensor_mod.F90
index 027fa9c1f3be897f5381c2aba5909a6151978485..c09a6f2f884843be8e7f1ca9915ea0547f3dc231 100644
--- a/src/main/sensor_mod.F90
+++ b/src/main/sensor_mod.F90
@@ -1749,7 +1749,7 @@ module SENSOR_MOD
          Sensor%Spatial_Resolution_Meters = 750
          Sensor%Platform_Name = 'NOAA-21'
          Sensor%WMO_Id = 226
-         Sensor%Instr_Const_File = 'viirs_20_instr.dat'
+         Sensor%Instr_Const_File = 'viirs_21_instr.dat'
          exit test_loop
       endif