Small tactical weapons dropped or fired from helicopters or fixed-wing aircraft may use rockets for propulsion, but still require electrical power for navigation (rudder and elevator) and other internal control systems, target tracking systems, wireless communications, and global positioning system (GPS) data acquisition. Similarly UAVs may employ a liquid fuel for the propulsion system but still require electrical power for other systems. Such aircraft typically employ a flight battery for electrical power. Cost-effective testing of such aircraft during development requires that the flight battery be reusable.