MARS, which stands for Military Auxiliary Radio System, is a program that is run by the United States military. It is a public service provided by amateur radio operators who are trained and certified to assist with military communications during times of crisis or disaster. MARS is activated by the military in response to a specific emergency or disaster situation, and MARS volunteers provide communications support to the military as needed. This can include transmitting messages and other information, and helping to coordinate the response efforts of various military units. MARS is an important part of the overall military communication system in the United States.