The Navy released the final air system engineering manufacturing and development request for proposals earlier this month for the MQ-25 unmanned tanker.
The service intends to award an EMD contract to a single air system vendor in late fiscal year 2018, according to Navy spokeswoman Jamie Cosgrove. The RFP was released Oct. 4.
Four vendors can compete in the competition: Boeing, General Atomics, Lockheed Martin and Northrop Grumman.
"The purpose of the EMD effort is to design, develop, deliver and test the air system, and to integrate it with the overall MQ-25 system," Cosgrove wrote in an Oct. 11 statement to Inside Defense.
The Navy plans to spend $2.3 billion through FY-22, but a recent Government Accountability Office report estimates the service will instead spend $2.5 billion for MQ-25 development.
The MQ-25 will be a UAS that operates from an aircraft carrier and provides refueling capabilities, and limited intelligence, surveillance and reconnaissance capabilities.