 They were deactivated on July 31, 1993.Marine Observation Squadron 155 (VMO-155) was formed at Marine Corps Air Station Quantico, Virginia on July 27, 1943.In November of that year they moved out to San Diego, California and on January 1, 1944, they were redesignated Marine Observation Squadron 1 (VMO-1) and deployed to Espiritu Santo.