The U.S. Navy has asked the shipbuilding industry to pitch ideas for its planned fleet of corvette-sized unmanned surface vessels, according to a draft request for proposal (RFP) announced Wednesday.

Externally-controlled navigation and lengths of about 180 feet are key specifications for bidders to observe in the Large Unmanned Surface Vehicle (LUSV) program.

The RFP also specifies the LUSV will be a high-endurance, multi-role reconfigurable ship with a large-payload capacity to augment the Navy’s surface force.

The draft RFP for the program starts the work of transitioning the effort from the Pentagon’s Strategic Capabilities Office two-hull Ghost Fleet into a full-fledged shipbuilding program, according to USNI News. The draft precedes a final RFP due out later this year.

A summary of the program sets out the future for LUSV navigation in U.S. Navy service:

The LUSV will be a high-endurance, reconfigurable ship able to accommodate various payloads for unmanned missions to augment the Navy’s manned surface force. With a large payload capacity, the LUSV will be designed to conduct a variety of warfare operations independently or in conjunction with manned surface combatants. The LUSV will be capable of semi-autonomous or fully autonomous operation, with operators in-the-loop (controlling remotely) or on-the-loop (enabled through autonomy).

These prototype design contracts will integrate common government furnished equipment warfare systems with commercially derived platforms in order to mature specifications and cost estimates to inform the next stage in the program, which will be the detail design and construction request for proposals.

Large unmanned surface vessels of this configuration will be procured starting in fiscal 2021 with competitive detail design and construction. Their planned usage is expected to, “affordably expand afloat strike and anti-surface warfare capacity in support of manned surface combatants.”

The service expects the LUSV to be capable of autonomous navigation, International Regulations for Preventing Collisions at Sea compliant maneuvering, and machinery operation with operators in the loop (controlling remotely) or on the loop (prompted action).

All weapons employment would be commanded remotely by manned warships or control stations.

The U.S. Navy intends to develop three versions of the unmanned vehicle — the LUSV, a medium unmanned surface vehicle and the extra-large unmanned undersea vehicle [XLUUV] — and requested $628.8 million in its 2020 budget for the programs.

Boeing Co. is already at work on the XLUUV program.