The organization that led to the Military Affiliate Radio System was called the Army Amateur Radio System (AARS). AARS was created in November 1925 by a few dedicated pioneers in the United States Army Signal Corps led by Captain Thomas C. Rives. His original intent was to enlist the talents of volunteer amateur radio operators as a ready source who could train soldiers in the then new technology of radio, as well as pursuing radio research and development to improve radio equipment within the Army. In addition, this support would be particularly useful during the mobilization of forces by providing a pool of already trained radio operators. Their efforts were very successful, and the present-day MARS program is the direct descendant of the work of those early pioneers.
Between 1925 and 1941, the AARS continued to operate and functioned more or less as an extracurricular activity for members of the Army Signal Corps, with its scope limited by budget cuts during the Great Depression. The AARS organization continued to operate until the United States entry into World War II on 7 December 1941, at which time radio amateurs were denied the use of the airwaves; both the amateur service and the Army Amateur Radio System were deactivated. Following World War II, the U.S. Army recognized the great importance of reactivating the AARS to train vitally needed communications personnel at a relatively low direct cost to the government, and in 1946 the AARS was reactivated. The AARS functioned as such until the creation of the Military Amateur Radio System in November 1948 with the establishment of separate Army and Air Force MARS programs, reflecting the creation of the Air Force as a separate service. The program's name was changed to the current Military Affiliate Radio System on 2 September 1952, in recognition of the organization's changing nature with the growing number of civilian volunteer members. Eventually, the Navy-Marine Corps MARS program was established officially on 17 August 1962, and began operations on 1 January 1963. This followed on the heels of the Cuban Missile Crisis and President Kennedy's concern for viable and extended communications capabilities.
During the Korean War, Vietnam War and Gulf War, MARS was most known for its handling of "Marsgram" written messages and providing "phone patches" to allow overseas servicemen to contact their families at home.
MARS continues to be very active today. Its primary mission is providing auxiliary to the US Military and emergency communications to such National agencies as FEMA and Homeland Security. MARS is also available to assist state, and local emergency response agencies; both public and select private agencies, such as the Red Cross.
On a day-to-day basis MARS members are available to handle messages to and from service men and women: active duty, reserve, guard, or retired and certain employees of the federal government who are stationed outside the U.S.