The U.S. Navy’s fleet of E-6B Mercury aircraft allows the President, Secretary of Defense, and U.S. Strategic Command to communicate with the nation’s nuclear forces during a crisis. However, those planes are getting old, prompting the Navy to begin pursuing a replacement called the E-XX Take Charge and Move Out (TACAMO) aircraft.

The Navy made its E-XX request for proposals (RFP) available to potential bidders starting on September 21, and submissions are due on Jan. 22, 2024. The service intends to award an engineering and manufacturing development contract to the winning offeror in October 2024.

The E-XX prime contractor will “integrate mature, government-defined TACAMO mission systems, including the Collins Aerospace Very Low Frequency (VLF) subsystem, into a government-furnished,” Lockheed Martin-built C-130J-30 Super Hercules aircraft, the Navy said. The Navy did not release delivery dates for the nine planned E-XX aircraft, saying the information is classified.


The E-6B is based on the Boeing 707 commercial airliner, which first flew in the 1950s. “The E-6B has been in service for more than three decades and continues to meet mission requirements, but is an aging airframe and, to ensure mission coverage, must be replaced,” the Navy said.

The mission is “critical in the deterrence and management of a nuclear conflict,” the Navy wrote in its fiscal year 2024 budget request, which is pending in Congress. The planes that perform that role “feature the ability to communicate on virtually every radio frequency band from very low frequency (VLF) up through advanced extremely high frequency (AEHF) using a variety of modulations, encryptions and networks, minimizing the likelihood of an emergency message being jammed by an enemy.”


Northrop Grumman announced in March that it intends to compete for the E-XX contract. It revealed the following month that its team includes Lockheed Martin Skunk Works; Raytheon Intelligence & Space, which has since merged with Raytheon Missiles & Defense to form RTX’s Raytheon business; and small businesses Crescent Systems Inc. and Long Wave Inc.

“Northrop Grumman has extensive weapons system integration and battle management expertise to compete for the U.S. Navy’s E-XX TACAMO weapon system alongside our industry team partners,” the company said.

Northrop Grumman is familiar with the existing fleet, having received a $111 million contract in February 2022 to improve the E-6B’s command, control and communications functions. The company delivered the first upgraded E-6B to the Navy in June 2023.


Collins Aerospace, an RTX business, indicated in a Sept. 26 statement that it is working with Sierra Nevada Corporation (SNC) “in support of” the E-XX TACAMO program, as well as the US Air Force’s counterpart, the Survivable Airborne Operations Center (SAOC), which will replace the aging E-4B Nightwatch National Airborne Operations Center (NAOC) aircraft. Collins declined to elaborate.

An L3Harris Technologies spokesperson said the company is “tracking the [E-XX] competition and evaluating how we can best support our Navy customer.”

As for SAOC, the Air Force said in a Sept. 26 statement that it “has concluded market research, finalized requirements, developed its acquisition strategy, and will execute a competitive source selection in calendar year 2023 to develop and field this critical system.”

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Marc Selinger is a journalist based in the Washington, D.C., area. He can be reached at Follow him on Twitter at @marcselinger.