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Around the same period, another development began attracting attention among people following military aircraft through publicly available flight-tracking services. Multiple Boeing E-6B Mercury aircraft were reported operating over parts of the United States. Because the aircraft are associated with America’s strategic nuclear command and communications infrastructure, their appearance immediately generated dramatic descriptions on social media.
The E-6B is sometimes informally called a “doomsday plane,” although that nickname can create a misleading impression about what the aircraft actually does. The Mercury is fundamentally a highly specialized communications relay and airborne strategic command-post aircraft. Its mission is designed to ensure that senior U.S. leadership can maintain communications with strategic forces even during an extreme national emergency in which ordinary communications infrastructure might be disrupted.
According to the U.S. Navy, the E-6B provides survivable and reliable airborne Nuclear Command, Control and Communications connectivity involving the president, secretary of defense and U.S. Strategic Command. One of its primary responsibilities is maintaining communications with U.S. Navy ballistic-missile submarines. These submarines form the sea-based component of the American nuclear triad and are designed to remain difficult for an adversary to locate.
The aircraft performs a mission commonly known as TACAMO, an acronym derived from “Take Charge and Move Out.” The mission predates the E-6 itself and exists to maintain communications between national command authorities and naval ballistic-missile forces during crises. The E-6 uses specialized communications equipment, including very-low-frequency systems and trailing-wire antennas, to perform that role.
The E-6B has another important strategic responsibility. It can function as an airborne command post for U.S. strategic forces and carries an Airborne Launch Control System. The Navy states that this capability can support the launch of U.S. land-based intercontinental ballistic missiles under appropriate authorized circumstances. This dual mission explains why the aircraft occupies such an important position within the broader American nuclear command-and-control architecture.