sentences:  After delivery to the Navy, the airship began operations as an advanced flying laboratory used to evaluate affordable sensor payloads, the development of new lighter-than-air (LTA) technologies and general flight support for other related research and development/science and technology (R&D/S&T) projects.It was the last airship to be operated by the U. S. military.The airship is propeller-driven by two Lycoming engines, providing a maximum cruise speed of just under .