High Altitude Airship Station-Keeping Analysis

Lighter-than-air vehicles were once widely utilized by most major militaries. The airship's extended range and flight endurance made them the optimal vehicle for surveillance and reconnaissance. These flight characteristics have created new interest in using lighter-than-air vehicles as high altitude surveillance and communications platforms. Future Department of Defense plans include high altitude airships that will operate at near space altitudes and take advantage of the low wind region in the upper atmosphere located at approximately 24 km. A high altitude airship could provide 24- hour coverage of a target area if operated in this low wind region. This study investigated the station-keeping abilities of two such high altitude airships: a large/fast design (AS #1) and a smaller/slower design (AS #2). The two baseline airship designs were subjected to the same simulated yearlong station-keeping mission using realistic upper atmospheric wind data over the designated target of Baghdad. Actual wind data was generated by the Navy's Fleet Numerical METOC Detachment and used to model the movements of both baseline airships. Their station-keeping capacity was determined by the duration of time each vehicle spent inside the targets coverage radius (552 km). The AS #1 design remained inside the operational radius for 87.67% of the year and the AS #2 design was only operational for 39.45% of the year. Neither airship maintained its station for the entire yearlong mission. This study concluded that advancements are required in propulsion or power production to decrease the size of the airship designs and increase the vehicles maximum velocity in order to counter the upper atmospheric winds.