Defense Primer: Nuclear Command, Control, and Communications (NC3)

Updated June 26, 2026

Defense Primer: Nuclear Command, Control, and

Communications (NC3)

The Department of Defense (DOD), which is “using a

secondary Department of War designation,” under

Executive Order 14347 dated September 5, 2025, is

replacing many elements of the U.S. nuclear command,

control, and communications (NC3) architecture as part of

the United States’ ongoing efforts to recapitalize its nuclear

forces. This architecture—composed of what some estimate

as more than 250 individual ground, space, and airborne

systems across military services, combatant commands, and

DOD components—supports the President’s exercise of

nuclear employment authority. (See CRS In Focus IF10521,

Authority to Launch Nuclear Forces.) Some of this

architecture, such as missile warning and tracking, may

overlap with existing or planned missile defense systems.

U.S. NC3 systems must operate at all times, including

during and after an attack on the United States, to sense and

assess the operational environment; facilitate planning and

decisionmaker conferencing; and transmit orders from the

President to U.S. nuclear forces: bombers in the air, ballistic

missile submarines (SSBNs) underwater, and

intercontinental ballistic missiles (ICBMs) deployed in silos

across the Midwest.

According to DOD, “U.S. [NC3] is necessary to

ensure the authorized employment and/or termination

of nuclear weapons operations, to secure against

accidental, inadvertent, or unauthorized access, and to

prevent the loss of control, theft, or unauthorized use

of U.S. nuclear weapons.”

The 2010, 2018, and 2022 Nuclear Posture Reviews

(NPRs)—periodic executive branch assessments of U.S.

nuclear weapons policy—highlighted the importance of

modernizing NC3. The Congressional Budget Office

(CBO) estimated in 2025 that DOD efforts to sustain and

modernize NC3 would cost $154 billion from 2025 through

2034. Through defense authorization and appropriation

legislation and hearings, Congress provides funding for and

oversight of NC3 sustainment and modernization.

Selected NC3 System Elements

Early Warning Radars

The Space Force operates a number of missile warning

radars to detect and track potential incoming ICBMs and

submarine-launched ballistic missiles. These radars include

capabilities like the Precision Acquisition Vehicle Entry

Phased Array Warning System (PAVE PAWS), the

Perimeter Acquisition Radar Attack Characterization

System (PARCS), and the COBRA DANE radar system.

These missile warning radars are periodically upgraded.

Missile Warning and Tracking

In 2011, the Space Force began deploying the Space-Based

Infrared System (SBIRS), a series of satellites and ground

systems to detect and track the launch of adversary missiles.

SBIRS satellites operate in geosynchronous (GEO) and

highly elliptical (HEO) orbits to observe missile launches

worldwide. SBIRS is DOD’s replacement for the 1970s

Defense Support Program satellites. The Space Force is

implementing the Next Generation Overhead Persistent

Infrared (Next-Gen OPIR) program to eventually replace

SBIRS. Next-Gen OPIR is composed of several GEO

satellites and a ground system. The Space Force is seeking

to terminate two polar-orbiting satellites and is building a

proliferated medium earth orbit constellation of missile

warning and tracking satellites. The FY2027 DOD budget

request included $6.9 billion in discretionary funding for

missile warning and tracking.

Hardened Satellite Communications

The Advanced Extremely High Frequency (AEHF)

constellation is a group of hardened communications

satellites operated by the Space Force. AEHF, first

launched in August 2010, replaced the Milstar constellation

from the 1980s. Paired with the Family of Beyond Line-OfSight Terminals (FAB-T) command post terminals, AEHF

aims to provide assured communications for nuclear and

conventional forces. The Space Force is developing a series

of satellites under the Evolved Strategic SATCOM (ESS)

program to eventually replace AEHF. The FY2027 budget

request included $2 billion for ESS.

Integrated Tactical Warning/Attack Assessment

The goal of the Integrated Tactical Warning/Attack

Assessment (ITW/AA) system is to integrate and collate

warning data from terrestrial and space-based sensors,

including ones detecting nuclear detonations, to assess

“whether an attack is occurring against North America or

U.S. assets or allies.” ITW/AA utilizes “dual

phenomenology”—a process that draws on data from “two

independent information sources using different physical

principles, such as radar and infrared satellite sensors” to

render and communicate its assessment to the President and

U.S. military leaders. This system is periodically upgraded.

E-4B National Airborne Operations Center

The E-4B National Airborne Operations Center (NAOC) is

designed to be a survivable command center for the

President and Secretary of Defense in the event of a

“national emergency or destruction of ground command

and control centers,” according to the Air Force. Based at

Offutt Air Force Base, NE, the E-4B is a modified Boeing

747 based on the E-4A originally delivered to the Air Force

in the 1970s. The Air Force is recapitalizing the system

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Defense Primer: Nuclear Command, Control, and Communications (NC3)

under the E-4C Survivable Airborne Operations Center

(SAOC) program. In April 2024, DOD announced that it

awarded the SAOC contract to Sierra Nevada Corp. DOD’s

FY2027 budget request included $2.2 billion for SAOC.

E-6B Mercury

The E-6B Mercury serves as a command relay to SSBNs

under Navy’s “Take Charge and Move Out” (TACAMO)

mission. Since 1998, it has also served as an airborne

launch control system under U.S. Strategic Command’s

(STRATCOM) Airborne Command Post (Looking Glass)

mission. Operating primarily out of Tinker Air Force Base,

OK, the E-6B is a modified Boeing 707 aircraft originally

delivered to the Navy as E-6A in 1989 and updated to the

E-6B in 1998. The Navy is upgrading the E-6B to extend its

operational life until FY2038. DOD requested $1.7 billion

for TACAMO modernization in FY2027. The E-130J

Phoenix II, a modified version of a C-130J-30 aircraft, will

execute only the TACAMO mission.

Looking Glass-Next

In December 2025, the Air Force announced an industry

day for the Looking Glass-Next program “aimed at

recapitalizing missions currently executed on the E-6B.” In

Section 154 of the National Defense Authorization Act for

Fiscal Year 2026 (NDAA; P.L. 119-60), Congress limited

the availability of certain Air Force funds until the Air

Force submitted a report to Congress on an acquisition

strategy for the Airborne Command Post capability. The

Air Force requested $65.3 million for Looking Glass-Next

in FY2027.

Issues for Congress

Congress has provided and may continue to consider

funding for and oversight of DOD efforts to modernize and

sustain the NC3 architecture. Areas of recent congressional

focus have included the following:

NC3 Governance and Prioritization

Some Members of Congress have expressed concern about

DOD’s ability to prioritize NC3 modernization. In Section

1052 of the FY2014 NDAA (P.L. 113-66), Congress

established the Council on Oversight of the National

Leadership Command, Control, and Communications

System (10 U.S.C. §171a). Following a 2018 DOD NC3

governance review, then-Secretary of Defense Jim Mattis

designated STRATCOM as the single operational

commander for NC3. The FY2019 NDAA conference

report (H.Rept. 115-874) stated that “conferees expect[ed]

to see clear improvements in lines of authority and

decision-making” after this change. In Section 1631 of the

FY2024 NDAA (P.L. 118-31), Congress established a

“unified major force program” for NC3 and required an

annual budget assessment of NC3 sustainment and

modernization. In March 2026 testimony, STRATCOM

Commander Admiral Richard Correll discussed the NC3

Enterprise Center (NEC) and its role in NC3 sustainment

and modernization.

Oversight of Costs and Schedule

Congress has tracked the development of NC3 systems.

Government Accountability Office (GAO) reports have

recommended that DOD provide Congress with additional

cost and schedule information on some systems to improve

congressional oversight. GAO’s June 2025 Weapons

Systems Annual Assessment report suggests potential cost

and schedule challenges for some NC3 systems. A January

2026 GAO report highlighted potential risks to delivering

missile warning and tracking satellites.

NC3 Vulnerability to Adversarial Attacks

Some Members of Congress have expressed concerns about

NC3 resilience to adversarial kinetic and other attacks.

DOD officials have discussed integration between nuclear

and conventional military command, control, and

communications systems. DOD has also sought to leverage

commercial systems for future NC3 improvements. U.S.

intelligence community assessments have described

Russia’s and China’s development of counterspace systems

that could disrupt or destroy U.S. satellites. DOD officials

have stated that an adversarial attack on U.S. NC3 assets

would be highly escalatory in a conflict, pointing in

particular to U.S. government concerns about Russia’s

development of a space-based nuclear capability.

Some Members of Congress have expressed concerns about

NC3 ability to operate while under cyberattack. Title 10,

Section 499, of the U.S. Code directs DOD to conduct an

annual assessment of NC3 cyber resiliency. Section 1512 of

the FY2024 NDAA (P.L. 118-31) added a requirement for

DOD to develop and implement a “threat-driven cyber

defense construct” for NC3. Section 1644 of the FY2022

NDAA (P.L. 117-81) directed DOD to conduct “an

independent review of the safety, security, and reliability”

of nuclear weapons, NC3, and ITW/AA to, among other

things, “prevent cyber-related and other risks that could

lead to the unauthorized or inadvertent use of nuclear

weapons.” The 2022 NPR endorsed this “Failsafe Review.”

“Human in the Loop”

Some Members of Congress have expressed concern about

the potential for autonomous systems to authorize a nuclear

weapons launch. The 2022 NPR stated that the United

States will maintain a human “in the loop … for all actions

critical to informing and executing decisions by the

President to initiate and terminate” nuclear weapon

employment. The Biden Administration also discussed the

need for a “human in the loop” with China and other

nuclear weapons states. Section 1638 of the FY2025

NDAA (P.L. 118-159) included a policy statement that the

use of artificial intelligence (AI) “should not compromise

the integrity of nuclear safeguards, whether through the

functionality of weapons systems, the validation of

communication from command authorities, or the principle

requiring positive human actions in execution” of a

presidential employment decision. In March 2026

testimony, Admiral Correll stated that, while STRATCOM

will “leverage AI and [machine learning] to expand

decision space for senior leaders,” it will “also remain

committed to ensuring that these capabilities will not

replace the human decisionmaking critical to advising and

executing Presidential directives regarding the use of

nuclear weapons.”

Anya L. Fink, Analyst in U.S. Defense Policy

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IF11697

Defense Primer: Nuclear Command, Control, and Communications (NC3)

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