The U.S. Department of Defense is reportedly moving ahead with allowing the Air Force to take the next step in its recapitalization of the JSTARS program.

JSTARS, or the Joint Surveillance Target Attack Radar System, is a Northrop Grumman-built ground surveillance command and control aircraft. Defense industry and government officials have been in the process of modernizing the fleet of E-8 aircraft, however budget concerns have delayed the process.

Defense News reports Kendall on Thursday signed an acquisition-decision memorandum approving the decision to move JSTARS into the next phase of the acquisition cycle.

The Pentagon's approval follows a meeting between Pentagon acquisition head Frank Kendall with Rep. Tom Graves, R-Ga., a member of the House Committee on Appropriations. Graves, who expressed concern on the delays, penned a letter to Defense Secretary Ash Carter in November, urging the Defense Department to move forward with the program.

"As an already high-demand, low-density military asset, we cannot afford to lose the JSTARS's BMC2/ISR unparalleled capability," Graves wrote. "However, the legacy fleet is rapidly approaching the end of its service life. Even now, on average, only half of the remaining fleet of 16 are operational at any given time due to the required maintenance on aging aircraft."

The Air Force began the effort to replace the aging E-8 aircraft in August, awarding pre-engineering contracts to Northrop Grumman, Lockheed Martin, L-3, and others.

The Air Force was expected to declare operational capacity for JSTARS in 2022, however the latest budget proposal has delayed the date until 2023.