uninhabited, so the issues associated with the design and operation of these aircraft should be considered UAV-unique. The committee focused on high-altitude technologies, especially aerodynamics/vehicle configuration and propulsion systems. HALE vehicles would generally be flight configured, with an emphasis on structural efficiency (light weight) to provide endurance. Because of the lightweight structures and large wingspans typical of HALE vehicles, aeroelasticity is an important factor. HALE vehicles would be generally autonomous and programmable because a key reason for using UAVs for long-duration missions is to avoid operator fatigue and reduced vigilance due to monotony.
The HSM vehicle type provided a focus on potential second-generation UCAVs. The goal for HSM vehicles will be to conduct high-risk combat operations at a significantly lower cost than inhabited systems. Because the key consideration for HSM vehicles will be survivability, design trade-offs will include stealth and maneuverability versus speed, maximum altitude, and damage tolerance. HSM vehicles will generally operate in concert with other vehicles (inhabited and uninhabited) and will be responsive to changes in mission at the direction of a remote human operator. The cost of operations and logistics will be critical for the HSM vehicle type.
The very low-cost vehicle type was chosen to focus attention on trade-offs between cost and performance. Low-cost vehicles will be small, autonomous, and inexpensive. Operating in concert with other vehicles as a single distributed system, individual low-cost vehicles will not carry high-value payloads, and the loss of an individual vehicle would present a small threat of mission failure or collateral damage. Important attributes of low-cost vehicles will be vehicle configuration, which will depend on payload, structural design criteria, reliability after long-term storage, and low-cost manufacturing.