In the United States military's strategic nuclear weapon

nuclear command and control Nuclear command and control (NC2) is the command and control of nuclear weapons. The U. S. military's ''Nuclear Matters Handbook 2015'' defined it as the "activities, processes, and procedures performed by appropriate military commanders and su ...

(NC2) system, an Emergency Action Message (EAM) is a preformatted message that directs nuclear-capable forces to execute specific Major Attack Options (MAOs) or Limited Attack Options (LAOs) in a

nuclear war Nuclear warfare, also known as atomic warfare, is a War, military conflict or prepared Policy, political strategy that deploys nuclear weaponry. Nuclear weapons are Weapon of mass destruction, weapons of mass destruction; in contrast to conven ...

. They are the military commands that the US military chain of command would use to launch a nuclear strike. Individual countries or specific regions may be included or withheld in the EAM, as specified in the Single Integrated Operational Plan (SIOP). The SIOP was updated annually until February 2003, when it was replaced by Operations Plan (OPLAN) 8044. Since July 2012, the US nuclear war plan has been OPLAN 8010-12, ''Strategic Deterrence and Force Employment''.

Overview

EAMs use

cryptographic protocol A cryptographic protocol is an abstract or concrete Communications protocol, protocol that performs a information security, security-related function and applies cryptographic methods, often as sequences of cryptographic primitives. A protocol desc ...

s (including such methods as digital signatures) to authenticate the messages, thereby ensuring that they cannot be forged or altered. In the United States, the EAM will be issued from the

National Military Command Center The National Military Command Center (NMCC) is a The Pentagon, Pentagon command and communications center for the National Command Authority (United States), National Command Authority (i.e., the President of the United States and the United Sta ...

(NMCC) at

the Pentagon The Pentagon is the headquarters building of the United States Department of Defense, in Arlington County, Virginia, across the Potomac River from Washington, D.C. The building was constructed on an accelerated schedule during World War II. As ...

or, if it has been destroyed by an enemy first strike, by the Alternate National Military Command Center - Site R at Raven Rock, Pennsylvania or by the U.S. Air Force E-4B Nightwatch aircraft/ U.S. Navy E-6A Mercury aircraft (TACAMO). The messages are sent in digital format to nuclear-capable major commands. The messages are then relayed to aircraft that are on alert by the U.S. Strategic Command at Offutt Air Force Base in

Omaha, Nebraska Omaha ( ) is the List of cities in Nebraska, most populous city in the U.S. state of Nebraska. It is located in the Midwestern United States along the Missouri River, about north of the mouth of the Platte River. The nation's List of United S ...

, via

single-sideband modulation In radio communications, single-sideband modulation (SSB) or single-sideband suppressed-carrier modulation (SSB-SC) is a type of signal modulation used to transmit information, such as an audio signal, by radio waves. A refinement of amplitu ...

radio transmitters of the High Frequency Global Communications System (formerly known as the Global High Frequency System). The EAM is relayed to missile-firing nuclear submarines via special transmitters designed for communication with submarines. The transmitters include those designed to operate at

Very Low Frequency Very low frequency or VLF is the ITU designation for radio frequencies (RF) in the range of 3–30 kHz, corresponding to wavelengths from 100 to 10 km, respectively. The band is also known as the myriameter band or myriameter wave ...

(VLF). The submarines pick up the message via special antennas. Nuclear-capable forces will then be expected to carry out an EAM without fail. Crewed bombers may be recalled, but missiles fired from land-based silos or from submarines cannot be recalled.

Skyking messages

Skyking messages, also known as "Foxtrot Broadcasts", are also read on the same network as EAMs. These messages will interrupt an EAM if needed to be read. They contain a higher priority and time-sensitive code for orders that need immediate attention.

In popular culture

The EAM system was featured extensively and used as one of the primary plot devices in the feature film '' Crimson Tide''. The start of a Sky King headed EAM message is briefly heard on the cockpit radio when the bomber crew are scrambled in the feature film '' By Dawn's Early Light''.

Overview

Skyking messages

In popular culture

See also

References

Further reading