The plane that transmitted the order to launch the US nuclear counterattack

The E-6 Mercury is considered a key element in ensuring America's nuclear retaliation capability when ground command posts are wiped out.

Compared to other fighter jets loaded with weapons, the E-6 Mercury looks harmless because it is not equipped with any weapons. However, this is one of the most important aircraft in the US military, acting as a mobile command post, tasked with ordering the launch of the country's nuclear missile arsenal, according to the National Interest.

Military expert Sebastien Roblin said that the basic mission of the E-6 is to maintain uninterrupted communication between the counterattack decision maker and the US strategic nuclear weapons deployment systems (TACAMO), especially when ground command centers are destroyed in the enemy's first nuclear strike.

Before the US developed the E-6, the TACAMO mission was handled by ground relay stations and the EC-130G/Q Hercules variant. However, the weakness of the TACAMO system is that they are placed in fixed positions on the ground, making them vulnerable to destruction in a preemptive nuclear strike, leaving the US without the ability to retaliate.

The first batch of six E-6A Mercurys entered service between 1989 and 1992. They were the last military variants of the Boeing 707 airliner. Equipped with 31 communications antennas, the E-6A's original mission was to communicate with US Navy submarines. With the installation of CFM-56 engines and larger fuel tanks, the E-6A could stay airborne for up to 15 hours or 72 hours when refueled.

To use the Very Low Frequency (VLF) communication channel, the E-6 must fly continuously in a circular orbit at high altitude, dragging a 2-8 km long antenna wire. The order to launch a nuclear retaliation from the US president will be transmitted by VLF signal through this aircraft to Ohio-class ballistic missile submarines hidden thousands of kilometers away.

An E-6B Mercury on TACAMO duty. Photo: Wikipedia.

The bandwidth of VLF transmitters is very limited, they can only send raw data at 35 characters per second, much slower than the 14K Internet modems of the 1990s. However, this transmission speed is still enough to send the Emergency Action Message (EAM), ordering the submarine to carry out a planned nuclear attack. The electronic systems on the E-6 are also hardened to withstand the electromagnetic pulse emitted by a nuclear explosion.

Between 1997 and 2006, the Pentagon upgraded the entire E-6A fleet to the E-6B version, allowing it to serve as a dual role as a communications station and an independent counterattack command center. They are a backup to the large E-4 Nightwatch airborne command post.

The E-6B version has a super high-frequency radio communication suite, capable of firing ballistic missiles in remote silos. This task was previously performed by the US Air Force EC-135 Looking Glass aircraft. The E-6B crew increased from 14 to 22 in airborne command missions, with an admiral or general in attendance.

The E-6B can access the MILSTAR satellite communications network, while the cockpit is upgraded with new electronics and equipment from the Boeing 737NG airliner. The highlight of the E-6B variant is that they have additional equipment pods mounted on the wings.

The E-6 Mercury's multi-purpose communications suite enables it to perform non-nuclear Command and Control (C3) missions. It has been deployed to Europe and the Middle East several times as an airborne C3 hub. The U.S. Navy has two squadrons that operate the E-6, VQ-3 "Ironman" and VQ-4 "Ghost," both of which are part of the Naval Strategic Communications Wing 1.

The US military maintains at least one E-6 on constant alert at all times. They often circle the ocean at low speed for up to 10 hours. The E-6s that serve as nuclear command posts are often on standby near an air base in Nebraska.

The US Navy is responsible for operating the E-6B fleet. Photo: Wikipedia.

The E-6 is a key element in the US nuclear deterrent force, ensuring the ability to respond nuclearally in the event of a first attack on the US, preventing potential opponents from acting recklessly, expert Roblin emphasized.

According to VNE