The mobile submarine simulator (MOSS) MK70 is a sonar decoy used by submarines of the United States Navy. It was a 10-inch vehicle, without an explosive warhead, but able to generate both an active sonar echo and a passive sound signature recorded to be extremely similar to that of the launching submarine. The purpose of MOSS was to create multiple targets all with the same acoustic signature. MOSS was originally developed by Gould until Westinghouse acquired that division. Some current underwater training targets are modeled after MOSS' design.