Raytheon and Northrop Grumman are developing new systems and concepts for close air support using an unmanned version of the twin-engine A-10 Thunderbolt II. The companies received contracts worth $7 million each in April 2011 under phase one of the U.S. Defense Advanced Research Projects Agency (Darpa) Persistent Close Air Support (PCAS) program.

The goal of the PCAS program is to demonstrate the capability for a joint terminal attack controller (JTAC) on the ground “to visualize, select and employ weapons at the time of his choosing from an optionally manned/unmanned A-10 platform,” according to a Darpa broad agency announcement issued in September 2010. The program will develop a “standard architecture for interoperability” between a JTAC and the aircraft, with the necessary equipment contained in a man-portable kit. An aircraft that is within 30 nm of a target is expected to deliver a weapon on that target within six minutes of a JTAC request. A live-fire demonstration is planned for 2015.

Raytheon and Northrop Grumman were also required to develop conceptual designs and system requirements for an operational PCAS system. Darpa is expected to choose one of the two companies for a 12-month second phase, scheduled to begin this spring. This phase will focus on the design of the A-10 platform and JTAC kit, culminating in a critical design review next year.

The companies declined to comment on the current status of the PCAS program, and Darpa did not immediately respond to a query from AIN. Raytheon announced last April that it is working with Rockwell Collins and GE Aviation on the PCAS program. More recently, on February 16, unmanned aircraft manufacturer Aurora Flight Sciences, of Manassas, Va., said it has been selected by Raytheon to develop the air vehicle technology. Aurora replaces Raytheon’s originally announced choice of Proxy Aviation Systems.

While the 1970s-vintage Fairchild Republic A-10 Warthog is the designated PCAS demonstration platform, Darpa said the intention is to develop a standard interface that can be used for a variety of manned and unmanned aircraft.