B-2 Spirit

The B-2 Spirit, a subsonic strategic bomber built by Northrop (later Northrop Grumman), is the only aircraft publicly acknowledged to deliver large, air-launched standoff weapons while remaining stealthy. Operated exclusively by the U.S. Air Force, this nuclear-capable flying wing—with its lambda wing shape, four engines, and a crew of two or three—uses stealth technology to slip through advanced air defenses. It can carry either conventional or thermonuclear ordnance, including up to eighty 500-pound Mk 82 JDAM GPS-guided bombs or sixteen 400-kiloton B61 nuclear bombs.

Development started in 1979 under the Carter administration as a black project called the Advanced Technology Bomber (ATB). The promise of this stealth bomber helped cancel the Mach 2-capable B-1A, but technical hurdles and rising costs slowed progress. By 1996, the program had built 21 B-2s at a total cost of $44.7 billion (roughly $91.8 billion in 2025), averaging $2.13 billion per aircraft (about $4.37 billion in 2025). The project’s enormous price tag—both to develop and operate—sparked controversy in Congress, especially after the Cold War ended and the need for a deep-penetration stealth bomber against the Soviet Union faded. Lawmakers cut the planned fleet from 132 to just 21.

The B-2 can reach an estimated ceiling of 50,000 feet (15 km), fly more than 6,900 miles (11,000 km) without refueling, and exceed 12,000 miles (19,000 km) with one midair refueling. It entered service in 1997 as the second stealth aircraft, following the Lockheed F-117 Nighthawk. Though designed primarily as a nuclear bomber, its first combat use came in 1999 during the Kosovo War, where it dropped conventional bombs. It later saw action in Iraq, Afghanistan, Libya, Yemen, the 2025 strikes on Iran, and the 2026 Iran war. The fleet is based at Whiteman Air Force Base in Missouri, with climate-controlled hangars that allow forward deployments to NSF Diego Garcia in the Indian Ocean, Andersen AFB on Guam, and RAF Fairford in the United Kingdom.

As of 2024, the Air Force operates 19 B-2s. One was lost in a 2008 crash, and another was likely retired after damage from a 2022 crash. The service plans to keep the B-2 in service until 2032, gradually replacing it with the Northrop Grumman B-21 Raider.

**Development**

**Origins** By the mid-1970s, aircraft designers had discovered a new way to evade missiles and interceptors: stealth. The idea was to build an airframe that deflected or absorbed radar signals, reflecting so little that the aircraft would be nearly invisible to radar. Without radar, enemies would have to rely on other detection methods—human eyes, infrared scanners, or acoustic locators—but these had short ranges or were poorly developed, allowing most aircraft to fly undetected, especially at night.

In 1974, DARPA asked U.S. aviation firms what the largest radar cross-section could be for an aircraft to remain effectively invisible. Northrop and McDonnell Douglas were chosen for further work. Lockheed already had stealth experience from the A-12 and SR-71, which featured canted vertical stabilizers, composite materials in key spots, and radar-absorbing paint. A major advance came from computer models that predicted radar reflections off flat surfaces, driving the design of faceted aircraft. The first such designs began in 1975 with Lockheed’s Have Blue test model.

By summer 1975, DARPA had launched the Experimental Survivability Testbed project. Northrop and Lockheed won initial contracts; Lockheed alone got the second round in April 1976, leading to Have Blue and eventually the F-117. Northrop also worked on a classified demonstrator, Tacit Blue, at Area 51 starting in 1979. That program developed stealth (low observables), fly-by-wire, curved surfaces, composite materials, electronic intelligence, and battlefield surveillance. The stealth technology from Tacit Blue later influenced other operational aircraft, including the B-2.

**Advanced Technology Bomber Program** By 1976, these efforts had shown that a long-range strategic stealth bomber was feasible. President Jimmy Carter learned of this in 1977, and it likely played a major role in canceling the B-1. Further studies were ordered in early 1978, after Have Blue had flown and proven the concepts. During the 1980 presidential campaign, Ronald Reagan repeatedly accused Carter of being weak on defense, using the B-1 as an example. In response, on August 22, 1980, Carter’s administration publicly revealed that the Department of Defense was developing stealth aircraft, including a bomber.

The Advanced Technology Bomber program officially began in 1979. Full development followed as a black project under the code name “Aurora.” After evaluation...