The program was canceled in 1977 due to its high cost, the introduction of the AGM-86 cruise missile that flew the same basic speed and distance, and early work on the B-2 stealth bomber.

Dubbed the B-1B, deliveries of the new variant began in 1985; the plane formally entered service with Strategic Air Command (SAC) as a nuclear bomber the following year.

[6] In 1955, the USAF issued requirements for a new bomber combining the payload and range of the Boeing B-52 Stratofortress with the Mach 2 maximum speed of the Convair B-58 Hustler.

[7] In December 1957, the USAF selected North American Aviation's B-70 Valkyrie for this role, a six-engine bomber that could cruise at Mach 3 at high altitude (70,000 ft or 21,000 m).

[14] Additionally, radars of the era were subject to "clutter" from stray returns from the ground and other objects, which meant a minimum angle existed above the horizon where they could detect a target.

In August 1963, the similar Low-Altitude Manned Penetrator design was completed, which called for an aircraft with a 20,000-pound (9,100 kg) bomb load and somewhat shorter range of 8,230 miles (13,240 km).

[24][25] In mid-1964, the USAF had revised its requirements and retitled the project as Advanced Manned Strategic Aircraft (AMSA), which differed from AMPSS primarily in that it also demanded a high-speed high-altitude capability, similar to that of the existing Mach 2-class F-111.

However, the introduction of the SLBM made moot the mobility and survivability argument, and a newer generation of ICBMs, such as the Minuteman III, had the accuracy and speed needed to attack point targets.

[32] President Richard Nixon reestablished the AMSA program after taking office, keeping with his administration's flexible response strategy that required a broad range of options short of general nuclear war.

[34] Nixon's Secretary of Defense, Melvin Laird, reviewed the programs and decided to lower the numbers of FB-111s, since they lacked the desired range, and recommended that the AMSA design studies be accelerated.

Additionally, the design featured large variable-sweep wings in order to provide both more lift during takeoff and landing, and lower drag during a high-speed dash phase.

[37] A pair of small vanes mounted near the nose are part of an active vibration damping system that smooths out the otherwise bumpy low-altitude ride.

[43] The B-1A mockup review occurred in late October 1971; this resulted in 297 requests for alteration to the design due to failures to meet specifications and desired improvements for ease of maintenance and operation.

During the 1976 federal election campaign, Jimmy Carter made it one of the Democratic Party's platforms, saying "The B-1 bomber is an example of a proposed system which should not be funded and would be wasteful of taxpayers' dollars.

Pentagon officials also stated that the AGM-86 Air-Launched Cruise Missile (ALCM) launched from the existing B-52 fleet would give the USAF equal capability of penetrating Soviet airspace.

No mention of the stealth work was made public with the program being top secret, but it is now known that in early 1978 he authorized the Advanced Technology Bomber (ATB) project, which eventually led to the B-2 Spirit.

[59][verification needed] On taking office, Reagan was faced with the same decision as Carter before: whether to continue with the B-1 for the short term, or to wait for the development of the ATB, a much more advanced aircraft.

[60] After 1985, the introduction of the SA-10 missile, the MiG-31 interceptor and the first effective Soviet Airborne Early Warning and Control (AWACS) systems would make the B-52 increasingly vulnerable.

[65] To deal with the introduction of the MiG-31 equipped with the new Zaslon radar system, and other aircraft with look-down capability, the B-1B's electronic warfare suite was significantly upgraded.

[67] The primary argument in favor of the B-1 was its large conventional weapon payload, and that its takeoff performance allowed it to operate with a credible bomb load from a much wider variety of airfields.

[97][98] In November 1993, three B-1Bs set a long-distance record for the aircraft, which demonstrated its ability to conduct extended mission lengths to strike anywhere in the world and return to base without any stops.

Expanding the internal bay to make use of the Common Strategic Rotary Launcher (CSRL), as well as utilizing six of the eight external hardpoints that had been previously out of use to keep in line with the New START Treaty, would increase the B-1B's weapon load from 24 to 40.

However, the bomber has been commonly called the "Bone"; a nickname that appears to stem from an early newspaper article on the aircraft wherein its name was phonetically spelled out as "B-ONE" with the hyphen inadvertently omitted.

The collapse of the Soviet Union had brought the B-1's nuclear role into question, leading to President George H. W. Bush ordering a $3 billion conventional refit.

[72] In 2003, accompanied by the removal of B-1Bs from the two bomb wings in the Air National Guard, the USAF decided to retire 33 aircraft to concentrate its budget on maintaining availability of remaining B-1Bs.

[133] On 14 July 2007, the Associated Press reported on the growing USAF presence in Iraq, including reintroduction of B-1Bs as a close-at-hand platform to support Coalition ground forces.

[134] Beginning in 2008, B-1s were used in Iraq and Afghanistan in an "armed overwatch" role, loitering for surveillance purposes while ready to deliver guided bombs in support of ground troops as required.

The aim was to detect and engage several small craft using existing weapons and tactics developed from conventional warfare against ground targets; the B-1 is seen as a useful asset for maritime duties such as patrolling shipping lanes.

[149] The 9th Bomb Squadron was deployed to Qatar in July 2014 to support missions in Afghanistan, but when the air campaign against IS began on 8 August, the aircraft were employed in Iraq.

[159][160] On 2 February 2024, the U.S. deployed two B-1Bs to strike 85 terrorist targets in seven locations in Iraq and Syria as part of a multi-tiered response to the killing of three U.S. troops in a drone attack in Jordan.