The caveat to the above are torpedoes delivered by missiles/rocket systems, designed for anti-submarine warfare. Some designs are a straightforward mating of a rocket-propulsion system to the torpedo with a purely attack profile, such as the American ASROC. More complex, aerial drone-based system with autopilot have also been deployed, such as the Australian Ikara. Most such systems are designed to deploy from surface ships, though exceptions exist such as the Soviet navy RPK-2 Viyuga, which can be launched from both surface ships and submarines.