The U. S. military's Nuclear Matters Handbook 2015 defined it as the "activities, processes, and procedures performed by appropriate military commanders and support personnel that, through the chain of command, allow for senior-level decisions on nuclear weapons employment.
The NCCS provides the President of the United States with the means to authorize the use of nuclear weapons in a crisis and to prevent unauthorized or accidental use.
It is an essential element to ensure crisis stability, deter attack against the United States and its allies, and maintain the safety, security, and effectiveness of the U.S. nuclear deterrent.
NCCS facilities include the fixed National Military Command Center (NMCC), the Global Operation Center (GOC), the airborne E-4B National Airborne Operations Center (NAOC), and the E-6B Take Charge and Move Out (TACAMO)/Airborne Command Post (Looking Glass)[3] The current Nuclear Matters Handbook 2020 [Revised] states: "The President bases this decision [to employ nuclear weapons] on many factors and will consider the advice and recommendations of senior advisors, to include the Secretary of Defense, the CJCS, and CCDRs.
"[4][5] The Ground Based Strategic Deterrent (GBSD) is entering the design review phase, as of 22 September 2021.