Nuclear bombs of the United States

Nuclear bombs of the United States
Name	United States nuclear weapons
Type	Thermonuclear, fission, boosted fission
Origin	United States
In service	1945–present
Used by	United States Armed Forces
Wars	Atomic bombings of Hiroshima and Nagasaki

Nuclear bombs of the United States are a class of explosive devices developed, tested, and fielded by the United States from 1945 onward that derive destructive energy from nuclear fission and fusion. They have shaped World War II aftermath politics, Cold War deterrence, and contemporary national security strategy through programs administered by the Manhattan Project, Los Alamos National Laboratory, and the Department of Energy. United States nuclear weapons influenced major treaties and crises involving the Soviet Union, United Kingdom, France, China, North Korea, and Iran.

History

The program began under the Manhattan Project during World War II with scientific leadership from J. Robert Oppenheimer, Enrico Fermi, Richard Feynman, and administration by the United States Army Air Forces. The first weapons, Little Boy and Fat Man, were used in the bombings of Hiroshima and Nagasaki in August 1945, producing immediate operational effects and triggering postwar debates in the Truman administration, the United Nations, and the emerging Cold War with the Soviet Union. The early Cold War era saw rapid expansion under presidents from Harry S. Truman to Dwight D. Eisenhower, guided by reports from the Acheson–Lilienthal Report and policies like NSC-68; competition with the Soviet atomic bomb project and events such as the Berlin Blockade accelerated weapons development. Later milestones included the era of thermonuclear weapons inaugurated by tests at Enewetak Atoll and political episodes like the Cuban Missile Crisis during the John F. Kennedy administration, détente under Richard Nixon, arms control with Jimmy Carter and Ronald Reagan culminating in agreements such as the SALT and INF Treaty, and post–Cold War adjustments during the Bill Clinton and George W. Bush presidencies.

Design and Types

United States designs evolved from gun-type fission devices like Little Boy to implosion-type bombs exemplified by Fat Man, then to boosted fission and staged thermonuclear designs such as the Teller–Ulam configuration developed at Los Alamos National Laboratory and tested at sites like Nevada Test Site and Bikini Atoll. Major categories include strategic gravity bombs (e.g., B83), tactical gravity bombs (e.g., B61), submarine-launched warheads on missiles like the Trident (e.g., W76), air-launched cruise missile warheads for platforms tied to USAF and US Navy delivery, and artillery or missile warheads used in earlier systems like the W48 and W88. Designers and institutions such as Edward Teller, Stanislaw Ulam, Los Alamos National Laboratory, and the Lawrence Livermore National Laboratory advanced physics, materials, and safety interlocks that differentiated early, mid-century, and modern arsenals.

Development and Testing

Testing programs involved the Manhattan Project era tests at Trinity and extensive atmospheric and underground programs at Nevada Test Site, Operation Crossroads at Bikini Atoll, and series like Operation Ivy and Operation Castle. These tests engaged personnel from Sandia National Laboratories, Lawrence Berkeley National Laboratory, and the Armed Forces Special Weapons Project, and produced environmental and health controversies prompting legislation debated in the United States Congress and adjudicated by courts influenced by plaintiffs tied to downwinders. International reactions spurred arms control diplomacy with the United Kingdom, Soviet Union, and France leading to treaties such as the Partial Test Ban Treaty and the Comprehensive Nuclear-Test-Ban Treaty. The end of atmospheric testing followed public concerns exemplified by advocacy from figures like Linus Pauling and organizations including the Natural Resources Defense Council.

Deployment and Delivery Systems

The United States pursued a nuclear triad of strategic forces comprising strategic bombers like the B-52 Stratofortress and B-2 Spirit, intercontinental ballistic missiles such as the Minuteman III and historical Titan II (rocket), and submarine-launched ballistic missiles deployed on Ohio-class submarines carrying the Trident family. Tactical deployment used aircraft like the F-15E Strike Eagle and F-16 Fighting Falcon, cruise missiles like the Tomahawk (conventional variants) and air-launched cruise missile programs, as well as early delivery systems such as the SM-65 Atlas and Thor in allied deployments (e.g., Project E). Command and control chains involved the NORAD, United States Strategic Command, and executive authorization procedures under presidential control, with contingency planning reflected in doctrines like Mutual Assured Destruction and targeting strategies debated in the Pentagon and among strategic analysts at institutions including the Rand Corporation.

Safety, Security, and Stewardship

Nuclear stewardship is managed by agencies including the National Nuclear Security Administration and the Department of Energy in partnership with Department of Defense components and national laboratories. Safety systems incorporate permissive action links, insensitive high explosives, and insensitive munitions standards developed with inputs from Sandia National Laboratories and Los Alamos National Laboratory. Security measures include physical security at bases like Nellis Air Force Base and Naval Base Kitsap, cybersecurity oversight from the National Security Agency, and intelligence cooperation with allies such as the United Kingdom and Canada. Stewardship activities—maintenance, life-extension programs, and stockpile surveillance—address aging warheads like the W80 and W87 without full-scale testing, guided by congressional oversight committees and independent reviews from bodies such as the JASON advisory group.

Effects and Casualties

Effects observed in wartime, testing, and hypothetical scenarios span blast, thermal radiation, prompt and residual ionizing radiation, and electromagnetic pulse; historical consequences include the immediate civilian casualties at Hiroshima and Nagasaki and long-term health impacts documented among survivors studied at institutions like the Radiation Effects Research Foundation. Testing produced environmental contamination at sites including Marshall Islands atolls and the Nevada Test Site, affecting indigenous populations and military personnel and prompting litigation involving agencies such as the Department of Justice. Scientific assessments by organizations like the National Academies of Sciences, Engineering, and Medicine and advocacy by groups such as Physicians for Social Responsibility have informed damage estimates, epidemiological studies, and public policy.

Policy, Strategy, and Arms Control

United States policy on nuclear weapons has balanced deterrence, nonproliferation, and arms control through presidencies and negotiations with counterparts in the Soviet Union/Russia, United Kingdom, and other nuclear states. Key agreements include the START, New START, the NPT, and ad hoc arrangements like the Nuclear Posture Review. Debates in the United States Congress, analyses from think tanks such as the Carnegie Endowment for International Peace and the Council on Foreign Relations, and rulings from the International Court of Justice and discussions at the United Nations have shaped modernization plans, declaratory policies on first use, no-first-use proposals, and initiatives addressing proliferation risks posed by actors like Pakistan, India, and North Korea.

Category:Nuclear weapons of the United States