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2016-05-01

B-2 Spirit Stealth Bomber: Centrepiece of Long Range Strike

The US Air Force’s B-2 stealth bomber is a key component of the nation’s long-range strike arsenal, and is one of the most survivable aircraft in the world. Its unique capabilities, including its stealth characteristics, allow it to penetrate the most sophisticated enemy defences. The B-2 has demonstrated its capabilities in several combat scenarios, including Operation Allied Force in Kosovo; Operation Enduring Freedom in Afghanistan, Operation Iraqi Freedom, and most recently, in Libya, during Operation Odyssey Dawn.

The B-2 is a low-observable, strategic, long-range, heavy bomber capable of penetrating complex and dense air-defence shields. It can fly 6,000 nautical miles unrefuelled and 10,000 nautical miles with just one aerial refuelling giving it the ability to fly to any point in the world within hours. With its ability to carry more than 20 tonnes of conventional and nuclear ordnance and deliver it precisely under any weather conditions, the B-2 also has the ability to change the outcome of a conflict with a single mission.

The prime contractor, responsible for the overall system design and integration, is Northrop Grumman Integrated Systems Sector. Boeing Military Airplanes Co., Hughes Radar Systems Group, General Electric Aircraft Engine Group and Vought Aircraft Industries, Inc., are key members of the aircraft contractor team.

The first B-2 was publicly displayed on November 22, 1988, when it was rolled out of its hangar at Air Force Plant 42, Palmdale, California. Its first flight was on July 17, 1989. Twenty-one aircraft were built in the original B-2 fleet. Today, the fleet consists of 20 aircraft, following the loss, in February 2008, of the Spirit of Kansas, which crashed while taking off from Andersen Air Force Base, Guam.

A USAF investigation released an accident report in June 2008, which concluded that the crash was caused by moisture in the port transducer units. These sensors sent distorted information to the air data system.

Nineteen B-2s are currently based at Whiteman Air Force Base, Missouri, home of the 509th Bomb Wing, while one aircraft is assigned to flight testing at Edwards AFB, California, to validate software and weapon systems upgrades.

Distinctive Design

The B-2’s distinctive profile comes from the unique ‘flying wing’ construction. The leading edges of the wings are angled at 33° and the trailing edge has a double-W shape. It is manufactured at the Northrop Grumman facilities in Pico Rivera and Palmdale in California.

After 10 years of service, the B-2 finally achieved full operational capability in December 2003. In the first three years of service, the operational B-2s achieved a sortie reliability rate of 90 per cent. An assessment published by the USAF showed that two B-2s armed with precision weaponry can do the job of 75 conventional aircraft.

AHFM Stealth Coating

Northrop Grumman has developed a new radar-absorbent coating to preserve the B-2’s stealth characteristics while drastically reducing maintenance time. The new material is known as alternate high-frequency material (AHFM). Four independently controlled robots spray it on. In November 2011, the USAF awarded a US$109m contract to Northrop Grumman for producing a redesigned aft deck for the B-2 stealth bomber.

B-2 Upgrade Programme

Northrop Grumman, B-2’s prime contractor, leads an industry team that is working on modernising the B-2. This is done to ensure that the aircraft remains fully mission capable against evolving worldwide threats. A range of upgrade programmes are working on improving the B-2’s lethality; its ability to receive updated target information during a mission, and its ability to collect, process and disseminate battlefield information with joint force commanders or other local first responders worldwide.

Northrop Grumman has successfully demonstrated to the US Air Force that its plans to upgrade key weapons management software for the B-2 stealth bomber are on track and ready to proceed to the next level of development.

The company successfully completed the critical design review (CDR) of the service’s Flexible Strike Phase 1 programme on February 3. CDR is a key review point in a three-year, US$102 million contract awarded to Northrop Grumman in August 2014. The contract covers the engineering and manufacturing development (EMD) portion of the Flexible Strike Phase 1 programme.

The B-2 currently uses the software called operational flight programme (OFP) to manage the communication between the jet and the hardware that holds and dispenses its weapons. Under its EMD contract, Northrop Grumman is replacing several mission-specific OFPs with a single OFP that can manage all of the B-2’s weapons carriage devices.

Weapons

The aircraft carries all its weapons internally and is fitted with two separate weapons bays in the centre of the aircraft. The B-2 has the capacity to carry up to 40,000lb of weapons, including conventional and nuclear weapons, precision-guided munitions, gravity bombs and a range of maritime weapons.

Each weapons bay is equipped with a rotary launcher and two bomb-rack assemblies. In tests, the B-2 successfully released B-61 and B-83 nuclear and mk84 conventional bombs from the rotary rocket launcher, and mk82 and CBU-87 conventional weapons from the bomb racks. The B61-11 is an earth-penetrating nuclear bomb for use against deeply buried and hardened targets. The B83 is a strategic free-fall nuclear bomb.

The B-2 can also carry the AGM-129 advanced cruise missile, which is a strategic cruise missile with a range estimated at up to 1,500 miles.

16 satellite-guided JDAM (joint direct attack munition) missiles can be carried. Northrop Grumman is converting the B-2 bomb rack assembly to a new ‘smart’ configuration, which will increase the number of JDAMs, which can be carried to a maximum of 80.

The aircraft will also be fitted with the joint standoff weapon (JSOW), joint air-to-surface standoff missiles (JASSM) and the wind-compensated munitions dispenser (WCMD) and will be able to carry up to 80 115kg small diameter bombs (SDB).

In June 2007, Northrop Grumman was awarded a contract to integrate the Boeing massive ordnance penetrator (MOP) weapon on the B-2. The MOP is GPS-guided, contains 2,400kg of explosives and is designed to penetrate hardened, deeply buried targets. B-2 is capable of carrying two MOP weapons, one in each weapons bay.

A generic weapons interface system (GWIS) has been fitted as part of the block 30 upgrade. The GWIS is an integrated digital software package, which allows the B-2 to carry different mixes of stand-off weapons and direct attack munitions on a single sortie, enabling the aircraft to attack up to four different types of targets on a single mission.

Under a contract awarded to Northrop Grumman in February 2008, the USAF has begun a programme to give the B-2 the capability to attack moving targets, using precision-guided weapons such as the small diameter bomb II. The contract involves the upgrade of displays and radar modes.

Radar and Engine

The B-2 carries a Lockheed Martin radar-warning receiver; a Northrop Grumman defensive aids system and the Lockheed Martin AN/APR-50 defensive management system (DMS).

The Raytheon AN/APQ-181 covert strike radar, operating at J band (Ku band), is a multi-purpose radar with terrain following and terrain avoidance modes. Testing at Edwards Air Force Base has demonstrated reliable terrain following at altitudes down to 200ft.

In April 2009, Northrop Grumman delivered to the US Air Force the first operational B-2 Spirit stealth bomber to be equipped with newly modernised radar. The updated aircraft will be used by air force to conduct additional field-testing of the radar, and the data gathered from these decisions will support future fielding decisions.

In November 2002, Raytheon was awarded a contract to develop a new Ku-band AESA (active electronically scanned array) antenna for the B-2 radar to avoid interference with commercial satellite systems after 2007. Flight tests with new radar began in October 2007 and continued until 2008. Installation of the new antenna on the B-2 fleet was completed by 2012.

Four General Electric F118-GE-100 turbofan engines, internally mounted in the body of the wings, power the aircraft. The engines have an exhaust temperature control system to minimise thermal signature.

Navigation and Communications

The B-2’s navigation suite includes a Rockwell Collins TCN-250 tactical air navigation system (TACAN) and a VIR-130A instrument landing system. Rockwell Collins supplies the communications equipment. A Milstar military strategic and tactical relay satellite communications system is installed in block 30 aircraft. The aircraft have been upgraded with Link 16 communications link.

Missions

From 1999 to 2003, the B-2 flew combat missions in three very different campaigns in distinct regions of the world with varied air threats. For Afghanistan, the B-2 opened the campaign soon dubbed Operation Enduring Freedom. It flew several missions, then pulled back to let other bombers and fighters continue the work, since the airspace held no threats.

At the beginning of Operation Iraqi Freedom in 2003, the B-2 again took on the most dangerous targets in areas where the remnants of Iraq’s air defences were most active. The B-2s logged 22 sorties from a forward base and 27 from Whiteman AFB, primarily during the first 10 days of Operation Iraqi Freedom. The B-2 targeted equipment in Republican Guard strongholds and struck fixed targets.

Innovation on the B-2 has not stopped, and its lineage within Northrop Grumman and the aerospace industry is still producing payoffs. Through constant innovation, the Northrop and Air Force team have improved on many of the most vexing compromises made for the sake of the breakthrough design.

Reference text/photos:

www.northropgrumman.com

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