The US Navy is taking a fresh look at the suitability of lighter than air (LTA) vehicles for unmanned surveillance and manned logistics missions, with its rekindled interest coming almost 50 years after it retired its last airships.

A request for information on LTA platforms/systems was released by the Naval Air Systems Command (Navair) last month, with industry responses due by late October.

The navy's PMA-262 persistent maritime unmanned aircraft systems programme office will lead the work, with its market research to identify potential contractors "to develop, test, integrate, produce, field and support LTA platforms/systems".

Its solicitation observes that "LTA unmanned aircraft systems (optionally manned) have the potential to provide persistent intelligence, surveillance, reconnaissance and communications support. A notional system may include multiple air vehicles, one ground control station, multi-mission (plug and play) payloads, and associated launch, recovery and support equipment," it adds.

The study is predicated on an air vehicle solution that could fly within 28 months, with an indicative performance specification baselining a 20,000ft (6,100m) service ceiling, mission radius of 9,250km (5,000nm), a 1,130kg (2,500lb) payload threshold, unmanned semi-autonomous operation with remote pilot take-off and landing, a 16kW power threshold and a seven-day loiter endurance at mission radius.

The RFI declares interest in conventional and hybrid airships, free-floating balloon systems and other high-altitude systems. It also seeks information on technologies such as advanced/alternative propulsion/power generation, vectored flight controls, buoyancy control, lightweight high-strength envelope materials, weather prediction/avoidance systems and ground-handling and ship interface concepts.

Navair is also seeking information on a manned LTA variant that could be employed for logistics applications. This would have a mission radius of 1,850km and a cargo payload of up to 500t.

The USN recently concluded a two-month evaluation of an Airship Management Services-owned Skyship 600 airship off Florida's southern coast in co-ordination with the US Coast Guard and National Office of Global Maritime Situational Awareness. Leased through PMA-262, the vehicle was configured with the assistance of the Naval Research Laboratory.

The USCG says recent studies "have indicated the utility and potential cost-effectiveness of airships" in the persistent maritime surveillance role. The recent demonstration was "an effort to examine the subject further" and test both the systems and crew mission loading and fatigue factors, it adds.

Source: Flight International