 Lockheed Martin performed studies that envisioned a number of different naval UCAV configurations, including "short takeoff and landing (STOVL)" aircraft that could be operated off of aircraft carriers, or "vertical attitude takeoff and landing (VTOL)" or "pogo" aircraft that could be operated off destroyers and other surface combat ships, or even submarines.Piloted pogo aircraft were flight-tested in the 1950s and proved a technological dead end at the time, since they couldn't carry a useful payload and were extremely difficult to land even under benign conditions.The payload limitations can be addressed with lighter materials and RATO-boosted takeoff, and modern digital flight control systems can address the landing issue.