Here's What You Need to Know: From nuclear bomber to missile carrier, the supersonic bomber has been flexible enough to adapt to a changing strategic environment.

Like many warplanes since the end of the Cold War, the B-1B bomber’s role in American airpower has changed to embrace new missions. Unlike other planes, the B-1’s mission changed even before the first aircraft took off. What started as a high-altitude, high-speed nuclear-penetration bomber has evolved into today’s all-purpose nonnuclear attack aircraft, a jack-of-all-trades with a huge carrying capacity for bombs and air-to-ground missiles.

After the cancellation of the supersonic XB-70 Valkyrie bomber, the U.S. Air Force struggled with the best approach to penetrating Soviet missile defenses with a manned bomber. The advent of surface-to-air missiles had made the airspace of the USSR particularly deadly and a tough nut to crack, and air-warfare strategists were unsure whether a high-altitude, high-speed dash or a low-altitude sneak was the best approach. After no fewer than four bomber studies, the B-1A bomber first flew in January 1974. High altitude and high speed had won out—the B-1A was capable of Mach 2.22 at a height of fifty thousand feet.

Unfortunately for the B-1A, it flew directly into unfavorable political winds. Presidential candidate Jimmy Carter considered the bomber wasteful and refused to back it, and the bomber stayed in limbo for the duration of his presidency. President Ronald Reagan, however, elected on a promise to rebuild America’s military, seized upon the optics of a sleek new bomber replacing older, 1960s-era B-52 bombers. The B-1 program was back on.

The intervening years, which had introduced new Soviet weapons including the MiG-25 Foxbat supersonic interceptor and the S-300 surface-to-air missile system (known as the SA-10 “Grumble” to NATO), made it clear that a high speed dash into Soviet airspace was no longer viable. In order to remain relevant, the B-1A would have to be redesigned into a stealthy, low-altitude penetrator. The B-1A morphed into the B-1B, which included, among other things, an 85 percent reduction in radar cross-section, an increase in defensive avionics and a one-third increase in maximum takeoff weight, to 477,000 pounds. The bomber could travel 7,455 miles unrefueled. As a consequence of abandoning the high-speed mission and embracing stealth, maximum speed fell to Mach 1.25.

The B-1B’s large fuselage could conceal a huge amount of weaponry, up to seventy-five thousand pounds of ordnance tucked within three weapons bays. In its original role as a long-range strategic nuclear bomber, the B-1B could carry eight B61 bombs, B83 bombs, or AGM-69A Short Range Attack Missiles per weapon bay. The bomber could also carry another fifty thousand pounds of weapons externally, and external hardpoints were designed to accommodate the AGM-86B Air Launched Cruise Missile. External stores ruined the B-1B’s carefully shaped radar cross-section, however, and were never actually used.

The United States withdrew the B-1B from the nuclear mission in 1991, and in 1995 Russian observers were allowed access to certify that all B-1Bs had been effectively denuclearized. Starting in 1997, the Conventional Munition Upgrade Program has converted B-1Bs to carry conventional weapons only. The Conventional Weapons Module, fitted into each of the B-1B’s three internal bomb bays, can carry up to twenty-eight Mk.82 high-explosive five-hundred-pound bombs or eight Mk. 84 two-thousand-pound bombs. The B-1B was also capable of carrying a wide variety of submunition-based weapons, such as the CBU-87 Combined Effects Munition, Gator mine system, or CBU-97 Sensor Fuzed Weapon, but those have been withdrawn from U.S. inventories due to international concerns about unexploded cluster munitions on the battlefield.

The B-1B may have lost its cluster-munitions capability, but it still has plenty of other weapons at its disposal. The B-1B can now carry up to twenty-four two-thousand-pound Joint Directed Attack Munition satellite-guided bombs at a time, giving it the capability to strike up to twenty-four separate enemy targets with an accuracy of up to forty-five feet with GPS guidance, or a hundred feet relying on the bomber’s internal navigation system. The B-1B’s combination of speed, range, a bellyful of precision bombs and a Sniper Advanced Targeting Pod made it an unusual but logical choice for loitering high over friendly U.S. forces in Iraq and Afghanistan. The B-1B could linger for hours over a battlefield, providing close air support to troops in contact or in situations where contact was imminent.

The B-1B’s newest and most interesting weapon is the AGM-158 Joint Air-to-Surface Standoff Missile, or JASSM, and the JASSM-ER (Extended Range). JASSM is a 2,250-pound cruise missile with a thousand-pound warhead and a two-hundred-mile range. JASSM-ER reportedly has double the range of the original version. The two missiles fit eight per weapons bay, for a total of twenty-four cruise missiles per aircraft. Outfitted with JASSM-ER missiles and in concert with B-52 bombers, Virginia-class attack submarines and Ohio-class guided-missile submarines, a force of B-1Bs could contribute to a single, overwhelming mass attack of precision-guided cruise missiles numbering in the many hundreds.

Even now, the Pentagon’s Third Offset strategy may provide yet another role for the B-1B. One outgrowth of the strategy is the concept of the Arsenal Plane, a flying missile carrier based on an existing aircraft. While several contenders for the Arsenal Plane have been proposed, including the B-52H bomber and the C-17 transport, the B-1B should also fall under consideration. The B-1B, already known to carry a large number of missiles, could carry even more on external hardpoints.

The B-1B’s role in America’s military arsenal has been more of an odyssey than others. From nuclear bomber to missile carrier, the supersonic bomber has been flexible enough to adapt to a changing strategic environment, embracing new roles as necessary. The B-1B is a bomber for a complex world, one that can bomb the Taliban one day and unleash two dozen cruise missiles against hardened, heavily defended targets in North Korea the next.

Kyle Mizokami is a defense and national-security writer based in San Francisco who has appeared in the Diplomat, Foreign Policy, War is Boring and the Daily Beast. In 2009 he cofounded the defense and security blog Japan Security Watch. You can follow him on Twitter: @KyleMizokami.

This article first appeared several years ago.

Image: Flickr