The US Air Force has no firm plans to replace a wide area surveillance capability if Congress later this year approves a proposal to retire the Northrop Grumman E-8C JSTARS in 2025, the head of the US Air Force’s Air Combat Command says.

The core of the wide area surveillance capability is the Northrop APY-7 radar, a 7.32m (22ft)-long sensor that can characterise and track moving targets in any weather across thousands of square miles.

Due to limitations of aperture size and power supply, any current or future sensors flown onboard a General Atomics Aeronautical Systems Inc MQ-9 or Northrop RQ-4 Global Hawk would be unable to match the search area and resolution of the JSTARS radar.

The ACC chief, Gen Mike Holmes, acknowledges the inability of unmanned platforms to match the JSTARS’ sensor capability.

“That’s part of what we’ll figure out with our advanced battle management system analysis of alternatives that we’re going to start this summer,” Holmes says.

The analysis is being launched after the USAF decided in the Fiscal 2019 budget submission to Congress to cancel a planned competition for a contract to develop a JSTARS replacement, using a business jet-sized aircraft.

The USAF decided such a platform would be unusable in combat scenarios after 2025, as Russia and China develop capabilities to defend airspace beyond the 155-mile detection range of the JSTARS radar.

But Air Force leaders know the proposed JSTARS replacement isn’t final.

“It’s entirely possible that the Congress could say, ‘No, we want you to build JSTARS,” Secretary of the Air Force Heather Wilson told reporters. “They need to understand that we don’t believe JSTARS will survive and be able to be deployed and used in a highly contested environment — China or Russia — post-2025.”

Meanwhile, the Air Force is continuing to fund development by Northrop of a wide area surveillance radar to replace the APY-7, Holmes says. Northrop had declined to describe the radar in any detail, but Holmes described it in a press conference as a modular system, with small modules of arrays that can be stacked together to form larger systems.

“We think there’s still an opportunity to use that technology in the Air Force and the other services for programmes,” Holmes says.

The only equivalent capability exists in the US Navy. The existence of the Navy’s littoral surveillance radar system (LSRS) emerged in 2006, as a radar with ground moving target indication capability for the Lockheed P-3C Orion fleet. The navy also funded Raytheon to develop a follow-on sensor — the Active Array Sensor (AAS) — for the Boeing P-8A, but its status and capabilities are kept secret.