The B-1B is a multi-role, long-range bomber, capable of flying intercontinental missions without refueling, then penetrating present and predicted sophisticated enemy defenses. It can perform a variety of missions, including that of a conventional weapons carrier for theater operations.
  The variable geometry B-1 bomber was designed as the successor for the elderly B-52. The B1-A was canceled, partly because the high-flying bomber was obsolete, and partly for political reasons. The B-1B differs from the B1-A with revisions in offensive avionics, defensive avionics, weapon payload, range, and speed. Major changes include improved avionics and systems, strengthened landing gear, optional weapons bay fuel tanks, external under-fuselage hardpoints for fuel and weapons, ejection seats rather than a crew escape capsule, fixed, rather than variable air inlets (limiting top speed to Mach 1.25 rather than the B1-A's Mach 2.3) with ducting masking the engines from radar.The B-1B uses radar and inertial navigation equipment enabling aircrews to globally navigate, update mission profiles and target coordinates in-flight, and precision bomb without the need for 		 ground-based navigation aids. The B1-B's stealthy shape, combined with electronic jamming equipment, infrared countermeasures, radar location, radar-absorbent material, and warning systems, form an integrated defense system for the aircraft. The craft's comprehensive electronic countermeasures package detects enemy radar and missiles attacking from the rear. It defends the aircraft by applying the appropriate countermeasures, such as electronic jamming or expendable chaff and flares.
  The B-1B represents a major upgrade in US long-range capabilities over the B-52, the previous mainstay of the bomber fleet. The aircraft has a overall payload of 134,000 lbs., including air launched cruise missiles, carried in three internal weapon bays and on six external hardpoints under the fuselage. The maximum internal weapons payload is 75,000 lbs. and maximum external weapons payload is 59,000 lbs.
  The USA's most numerically important strategic bomber, the B-1 has had to endure criticisms of its high cost, cancellation, a 20 year gestation period and operational serviceability problems. The B-1 resulted from the USAF's Advanced Manned Strategic Aircraft program of 1965 to find a low altitude penetration nuclear bomber to replace the B-52. A North American Rockwell design was eventually selected for further development in 1970 from competing designs from Boeing and General Dynamics. The first of four B1-A 		 prototypes first flew on December 23, 1974. However, in 1977 US President Jimmy Carter canceled planned B1-A production, but test flying continued. The B-1 was resurrected in 1981 when Ronald Reagan was installed as US President and 100 improved production B-1 s, designated B1-B, were ordered. North American Aircraft (now part of Boeing), produced 100 B-1B aircraft for the US Air Force in the 1980's.
  The B1-B first flew on October 18, 1984 and was delivered to the Air Force at Edwards AFB, California later that month, just 33 months after contract go-ahead. The first operational B1-B,The Star of Abilene, was delivered to the Strategic Air Command in June 1985 at Dyess AFB, Texas. On October 1, 1986 the B-1B achieved Initial Operational Capability and by November 1986 B1-B's were coming off the production line at a rate of four per month. The final B-1B was delivered May 2, 1988.
  During the Cold War, heavy bombers were used primarily for nuclear deterrence. With the collapse of the Soviet Union, the B1-B's main role changed to a focus on more conventional warfare. The $2.7 billion CMUP program is intended to convert the B-1B from a primarily nuclear weapons carrier to a conventional weapons carrier as well as improve its mission capable rate. The B-1B currently holds 36 world records for speed, payload and distance...