The United States Navy is upgrading its sixteen E-6B Mercury aircraft so that they can receive real-time video and other data requiring high capacity communications. Originally costing $142 million each, the E-6s were designed to provide secure communications for the Navy's force of ballistic missile subs (SSBNs). The last major upgrade (from E-6A to E-6B) was nine years ago.
The E-6Bs are modified 707s that, in the late 1990s, replaced the older EC-130 TACAMO aircraft. E-6Bs have a top speed of 981 kilometers per hour and can loiter for six hours after flying 12,144 kilometers. These aircraft have a crew of 14 and average about 95 hours of flight time a month. Like the E-4B airborne command center aircraft (based on the 747), the E-6B can be refueled in the air. These aircraft carry an Airborne Command Post (ABNCP) and a large amount of communications gear, including SATCOM, MILSTAR, and VLF systems. The E-6Bs are usually from bases on the east coast (Maryland), the Mid-West (Nebraska), and west coast (California), while the main operating base is also in the Mid-West (Oklahoma).
The E-6Bs are one of several ways to communicate with submerged SSBNs. There are also satellite communications but the E-6Bs are back-up in case serious damage is done to the satellite communications network or the land based headquarters that will issue orders to launch ballistic missiles.
The SSBNs are the ultimate deterrent to nuclear attack. While it is theoretically possible to strike first and destroy the underground silos containing American nuclear weapons, there are always some SSBNs at sea. While out there the SSBNs concentrate on hiding and only occasionally coming close to the surface to receive messages (broadcasting anything could reveal the subs location). Thus when an SSBN gets the encrypted orders to fire its missiles, it means the United States has been blasted and the SSBNs must now punish the attackers for destroying life as we knew it.
