The U.S. Navy has slipped by a few weeks the release of its draft request for proposals (RFP) for the service’s project to field at least one squadron of surveillance UAVs onboard an aircraft carrier within the next decade.

The draft Unmanned Carrier-Launched Airborne Surveillance and Strike (Uclass) RFP was slated for release this month, but it is now expected to be out by the end of September, says Jamie Cosgrove, a service spokeswoman. Until that document outlines the Navy’s specific needs, debate still continues over requirements, including how stealthy the aircraft needs to be.

Industry and military sources suggest there has been discussion between the Navy leadership, military leaders on the Joint Staff and top officials in the Office of the Secretary of Defense over how the design of the air vehicle should balance payload, endurance and survivability.

The requirement of operating on an aircraft carrier puts a premium on these qualities. Rear Adm. Mat Winter, program executive officer overseeing Navy unmanned aircraft, said last month that either a stealthy, tailless design or a winged body with a tail could satisfy the Navy’s needs. He declined to outline specific requirements.

Lockheed Martin, producer of the stealthy F-35 and F-22 fighters, is pitching a tailless aircraft designed to operate in an anti-access area denial (A2AD) environment, such as that expected in Pacific countries such as North Korea or China. Northrop Grumman, builder of the stealthy B-2 and tailless X-47B Unmanned Combat Air System (UCAS), is also opting for higher-end survivability, according to industry sources.

By contrast, General Atomics and Boeing are expected to de-emphasize stealth in favor of more endurance and payload. “What is not clear yet is how many provisions there need to be to go beyond a contested airspace [environment and] up to an A2AD environment,” says Bob Ruszkowski, Lockheed Martin’s Uclass program capture lead. “We believe that Uclass needs to be a fifth-generation capability,” he adds, referring to the company’s marketing term for a combination of stealthy shaping and avionics fusion found in the F-22 and F-35.

Lockheed’s design builds on lessons not only from those manned fighters but from previous work on the company’s Polecat unmanned aircraft demonstrator and the subsequently fielded RQ-170. This aircraft, the Sentinel, carries intelligence-collecting sensors inside a stealthy design; one of the aircraft, which is said to have little endurance, was lost over Iran last year while conducting a mission.

Stealth, however, is perceived to require higher development, production and maintenance costs. Ruszkowski says Lockheed’s experience with the F-35C is providing lessons on affordability; but that aircraft has yet to conduct ship trials.

Winter says the Navy expects to field the first Uclass air vehicle within three to six years of contract award; the service could be allowing for so much time so that the competition can be as inclusive as possible for bidders.

The Navy will likely select a cost-plus contract to minimize the amount of risk put on the contractor while developing the system, but it is unclear how the Navy will grade the bids, including prioritization of technology readiness for a set of basic, or threshold, requirements and objectives.