The six crew members were identified as Maj. Christopher M. Cooper , 33 , aircraft commander ; Maj. Brent D. Williams , 37 , navigator ; Capt. Michael K. Dodson , 31 , co-pilot ; 1st Lt. Joshua D. Shepherd , 26 , navigator ; 1st Lt. Robert D. Gerren , 32 , electronic warfare officer ; and Col. George Martin , flight surgeon .