High Altitude Long Endurance Air Vehicle Analysis of Alternatives and Technology Requirements Development

TLDR

The study aims to identify technology improvements—higher energy‑storage specific energy, better solar‑cell efficiency, and reduced airframe drag and mass—to enable a solar‑regenerative HALE UAV to meet full mission requirements. The authors conducted an analysis of alternatives and technology‑requirements study for hurricane‑science and communications‑relay missions, deriving sixteen HALE UAV configurations and using a solar‑regenerative HTA design for further mission and technology development analyses. The preferred configuration is a diesel‑fueled HTA wing‑body‑tail, and cost‑effectiveness analysis indicates that maximizing endurance alone is sub‑optimal; the solar‑regenerative vehicle can only operate during long days and short nights at higher latitudes in summer.

Abstract

An Analysis of Alternatives and a Technology Requirements Study were conducted for two mission areas utilizing various types of High Altitude Long Endurance (HALE) Unmanned Aerial Vehicles (UAV). A hurricane science mission and a communications relay mission provided air vehicle requirements which were used to derive sixteen potential HALE UAV configurations, including heavier-than-air (HTA) and lighter-than-air (LTA) concepts with both consumable fuel and solar regenerative propulsion systems. A HTA diesel-fueled wing-body-tail configuration emerged as the preferred concept given near-term technology constraints. The cost effectiveness analysis showed that simply maximizing vehicle endurance can be a sub-optimum system solution. In addition, the HTA solar regenerative configuration was utilized to perform both a mission requirements study and a technology development study. Given near-term technology constraints, the solar regenerative powered vehicle was limited to operations during the long days and short nights at higher latitudes during the summer months. Technology improvements are required in energy storage system specific energy and solar cell efficiency, along with airframe drag and mass reductions to enable the solar regenerative vehicle to meet the full mission requirements.