B-2 Spirit

The Northrop Grumman B-2 Spirit is a multi-role stealth heavy bomber, capable of deploying both conventional and nuclear weapons. It is operated exclusively by the United States Air Force. Its development was a milestone in the modernization program of the U.S. Department of Defense. The B-2's stealth technology is intended to aid the aircraft's penetration role in order to survive extremely dense anti-aircraft defenses otherwise considered impenetrable by combat aircraft.

Development

The B-2 started life as a black project known as the High Altitude Penetrating Bomber (HAPB), then became the Advanced Technology Bomber (ATB), which became the B-2 Spirit. The bomber's design was changed in the mid-1980s when its mission profile was changed from high-altitude to low-altitude, terrain following. The redesign delayed the B-2's first flight by two years and added about $1 billion to the program's cost.[4] An estimated US$23 billion was secretly spent for research and development on the B-2 in the 1980s.[citation needed] At the program's peak, 13000 people were employed at a dedicated plant in Pico Rivera, California for the plane's engineering and some manufacturing.[5]

The first B-2 was publicly displayed on 22 November 1988, when it was rolled out of its hangar at Air Force Plant 42, Palmdale, California, where it was built. Its first public flight was on 17 July 1989. The B-2 Combined Test Force, Air Force Flight Test Center, Edwards Air Force Base, California, is responsible for flight testing the engineering, manufacturing and development aircraft.

The original procurement of 132 aircraft was later reduced to 75 in the late 1980s. In his 1992 State of the Union Address, President George H.W. Bush announced total B-2 production would be limited to 20 aircraft, with a total inventory of 21 by upgrading the first test aircraft to B-2A Block 30 standard.[6] This reduction was largely a result of the disintegration of the Soviet Union, which effectively rendered void the Spirit's primary mission.

The cost of the B-2 program in 1994 dollars was reported at $737 million per plane; however, the total cost of the program with development, spares, and facilities averaged over $2.1 billion per plane as of 1997 according to the B-2 program office.[3]

Northrop made a proposal to the USAF in the late 1990s to build additional aircraft for ~$550M each. This more accurately reflects the per aircraft cost if the full order had been manufactured. The high development costs included: another stealth prototype (now at the USAF museum), security costs which included inefficiencies of separating design teams, the development of a computer aided design system which requires no paper (it was the first aircraft so designed), a totally computerized manufacturing control system (the first of its kind), and a computerized maintenance system to help crew chiefs with the most complex aircraft yet made

Design

As with the B-52 Stratofortress and B-1 Lancer, the B-2 provides the versatility inherent in manned bombers. Like other bombers, its assigned targets can be canceled or changed while in flight, the particular weapon assigned to a target can be changed, and the timing of attack, or the route to the target can be changed while in flight. In addition, its low-observable, or "stealth," characteristics give it the ability to penetrate an enemy's most sophisticated defenses and attack its most heavily defended targets.
A close-up of a B-2
A close-up of a B-2

The blending of low-observable technologies with high aerodynamic efficiency and large payload gives the B-2 significant advantages over previous bombers. Its range is approximately 6,000 nautical miles (11,100 km) without refueling. Also, its low-observation ability provides the B-2 greater freedom of action at high altitudes, thus increasing its range and giving a better field of view for the aircraft's sensors. It combines GPS Aided Targeting System (GATS) with GPS-aided bombs such as Joint Direct Attack Munition (JDAM). This uses its passive electronically scanned array APQ-181 radar to correct GPS errors of targets and gain much better than laser-guided weapon accuracy when "dumb" gravity bombs are equipped with a GPS-aided "smart" guidance tail kit. It can bomb 16 targets in a single pass when equipped with 1,000 or 2,000-pound bombs, or as many as 80 when carrying 500-lb bombs.

The B-2's stealth comes from a combination of reduced acoustic, infrared, visual and radar signatures, making it difficult for defenses to detect, track and engage. Many aspects of the low-observability process remain classified; however, the B-2's composite materials, special coatings and flying wing design (which cuts down on the number of leading edges) contribute to its stealth abilities. The B-2 uses radar absorbent material and coatings that require climate-controlled hangars for maintenance.[7]
B-2 during aerial refueling over the Pacific Ocean. In-flight refueling capability gives the B-2 a range limited only by maintenance and crew endurance.
B-2 during aerial refueling over the Pacific Ocean. In-flight refueling capability gives the B-2 a range limited only by maintenance and crew endurance.

The B-2 has a crew of two; a pilot in the left seat and mission commander in the right.[8] The B-2 has a provision for a third crew member if required in the future.[9] For comparison, the B-1B has a crew of four and the B-52 has a crew of five.[8] B-2 crews have been used to pioneer sleep cycle research to improve crew performance on long flights. The B-2 is highly automated, and unlike single-seat fighters, one crew member can sleep, use a flush toilet or prepare a hot meal while the other monitors the aircraft.

Operational history

The first operational aircraft, christened Spirit of Missouri, was delivered on December 17, 1993. The B-2 fleet is based at Whiteman Air Force Base in Missouri. Depot maintenance for the B-2 is accomplished by United States Air Force contractor support and managed at the Oklahoma City Air Logistics Center, Tinker Air Force Base, Oklahoma.[8] Originally designed to deliver nuclear weapons, modern usage has shifted towards a flexible role with conventional and nuclear capability.

The prime contractor, responsible for overall system design and integration, is Northrop Grumman Integrated Systems Sector. Boeing Integrated Defense Systems, Hughes Aircraft (now Raytheon), General Electric Aircraft Engines and Vought Aircraft Industries, are members of the aircraft contractor team. Another contractor, responsible for aircrew training devices (weapon system trainer and mission trainer) is Link Simulation & Training, a division of L-3 Communications formerly Hughes Training Inc. (HTI).[11] Link Division, formerly known as CAE - Link Flight Simulation Corp. Link Simulation & Training is responsible for developing and integrating all aircrew and maintenance training programs.

Combat

The B-2 has seen service in three separate campaigns. Its debut was during the Kosovo War in 1999. The B-2 first introduced the satellite guided JDAM in combat use. Since then, the aircraft has operated over Afghanistan in Operation Enduring Freedom and Iraq in Operation Iraqi Freedom. During the Iraq campaign, B-2s were temporarily operated from Diego Garcia. Later missions to Iraq launched from Whiteman Air Force Base in Missouri. This resulted in missions lasting over 30 hours and one mission of over 50 hours.

The Pentagon's Operational Test and Evaluation 2003 Annual Report noted that the B-2's serviceability for FY03 was still inadequate, mainly due to maintenance on the B-2's Low Observable materials. The evaluation also noted that the Defensive Avionics suite also had shortcomings with pop-up threats.[12] Despite these problems the B-2 reached full operational capability in December 2003.[8] The B-2 maintained high mission capable rates for Operation Iraqi Freedom, dropping 583 JDAMs during the campaign.

Specifications (B-2A Block 30)

Data from Global Security[30]

General characteristics

* Crew: 2
* Length: 69 ft (21 m)
* Wingspan: 172 ft (52.4 m)
* Height: 17 ft (5.2 m)
* Wing area: 5,000 ft² (460 m²
* Empty weight: 158,000 lb (71.7 t)
* Loaded weight: 336,500 lb (152.6 t)
* Max takeoff weight: 376,000 lb (171.0 t)
* Powerplant: 4× General Electric F118-GE-100 turbofans, 17,300 lbf (77 kN) each

Performance

* Maximum speed: 410 knots (760 km/h, 470 mph)
* Range: 5,600 nm (10,400 km, 6,400 mi)
* Service ceiling 50,000 ft (15,000 m)
* Wing loading: 67.3 lb/ft² (329 kg/m²
* Thrust/weight: 0.205

Armament

* 2 internal bays for 50,000 lb (22,700 kg) of ordnance.[31]
o 80× 500 lb class bombs (Mk-82) mounted on Bomb Rack Assembly (BRA)
o 36× 750 lb CBU class bombs on BRA
o 16× 2000 lb class weapons (Mk-84, JDAM-84, JDAM-102) mounted on Rotary Launcher Assembly (RLA)
o 16× B61 or B83 nuclear weapons on RLA

Later avionics and equipment improvements allow B-2A to carry JSOW and GBU-28s as well. The Spirit is also designated as a delivery aircraft for the AGM-158 JASSM when the missile enters service.