The Flight Surgeon Badge is presented to those members of the military who are both qualified medical officers and certified flight surgeons. The original Flight Surgeon Badge was first issued by the United States Army Air Forces during World War II. Since then, the decoration has expanded into four separate military service versions of the Flight Surgeon Badge, with the United States Marine Corps the only branch of service which does not issue the Flight Surgeon Badge.[citation needed] To be awarded the Flight Surgeon Badge, a service member must be a commissioned officer who holds a designation as a medical staff officer. Following the completion of initial military medical training, a service member must undergo further study in Aerospace Medicine. Upon completion of a medical residency, those eligible for the Flight Surgeon Badge must next undergo basic air operations training consistent with that of a qualified aircrew member. Once all requirements have been met, a service member must complete a probationary period to include a series of in-flight missions and medical skills evaluation. Only at the end of this lengthy process with the service member will be awarded the Flight Surgeon Badge