* During the late 1940s and early 1950s, Jack Northrop of the Northrop company worked on a series of flying-wing bombers, none of which actually reached production. However, they did attract a great deal of public attention, being seen as futuristic, and were even featured in science-fiction movies such as THE WAR OF THE WORLDS.
A few decades later the notion that the future belonged to the flying wing seemed laughable, but Northrop had the last laugh. There were tales that radar had trouble picking up the uncluttered lines of a flying wing, and as the US Air Force turned towards "stealthy" aircraft in the 1970s and 1980s, the flying wing bomber was revived in the form of the Northrop Grumman "B-2 Spirit" -- the first flying wing to enter full operational service, the biggest stealth aircraft built to date, and one of the most expensive aircraft ever made. A list of illustration credits is provided at the end.
* Formal work on the development of "low-observable" or "stealth' aircraft in the US began in late 1974, when the Defense Advanced Research Projects Agency (DARPA), a Pentagon organization that works on "blue sky" advanced technologies, began Project HARVEY, an effort to build a stealthy aircraft. The project was named after a famous comedy about a giant invisible rabbit named, of course, Harvey.
Project HARVEY was not actually the first time the US had incorporated stealth features into aircraft. In the early 1960s, Firebee target drones had been modified for the reconnaissance role as "Lightning Bugs" or "Fireflies". They had been given stealth enhancements, including pads of radar-absorbing material (RAM) on the sides of the fuselage; and a wire mesh over the air intake to mask the blades of the engine compressor, which tends to sparkle or "glint" on radar as it spins, like a spinning disco ball in a lights show. The high-flying Lockheed SR-71 Blackbird reconnaissance aircraft was designed to be stealthy as well, though it also used high altitude and speed for protection.
The goals of Project HARVEY were much more ambitious: to create an aircraft that could survive on stealth alone. DARPA awarded study contracts to McDonnell Douglas and Northrop in January 1975. Lockheed officials found out about HARVEY through the grapevine and insisted on participating, paying for their design effort out of company funds. That was a gamble, but it paid off: Northrop and Lockheed were selected by DARPA to design a stealth demonstrator, the "Experimental Survivable Testbed (XST)", while McDonnell Douglas was eliminated from the competition. The XST program's goals did not include building a flight demonstrator; Northrop and Lockheed were to build large-scale mockups, which would then be mounted on a pole at Holloman AFB in New Mexico and subjected to tests to determine their "radar cross-section (RCS)".
Work on the Northrop demonstrator was conducted by a team under John Cashen, a pushy sort who had come to Northrop after working at Hughes on how targets appeared to radar and infrared sensors, and Irv Waaland, a designer who had come over to Northrop from Grumman. Although the Lockheed team used a computer program to come up with their design for the XST, Cashen said later that Northrop didn't have such a luxury, and worked up their design using a combination of theoretical analysis and cut-and-try experiments.
The Lockheed team won the XST competition in March 1976, and went on to build two HAVE BLUE stealth demonstrator aircraft, which paved the way to the larger Lockheed F-117 stealth fighter. Northrop lost because one of the team's initial design assumptions was that a stealthy aircraft should be hardest to pick up from the front and below, but the DARPA requirement, rightly or wrongly, insisted on measuring stealthiness from four quadrants. The Lockheed design proved better able to meet the all-round stealth requirement. Lockheed also had an advantage in possessing a good knowledge of RAM technology, which that company had developed for the SR-71.
However, in December 1976, DARPA officials called up Northrop to discuss a stealth aircraft as part of the Pentagon's ASSAULT BREAKER effort. ASSAULT BREAKER was a wide-ranging program that envisioned use of new "smart" munitions, deep-penetrating strike platforms, and advanced sensors to smash numerically-superior Soviet armor forces in the case of a European war. DARPA wanted Northrop to study a stealthy "Battlefield Surveillance Aircraft -- Experimental (BSAX)" that would spot targets for ASSAULT BREAKER weapons.
Since BSAX was supposed to loiter around a battlefield instead of performing an attack and leaving, it would present all angles to an enemy, and so required all-round stealth. An initial model of BSAX was tested in the summer of 1977, with results that Waaland later described as "disastrous". One of the design team members, Fred Oshira, did some rethinking of the design and came up with a solution, a new airframe design that gave very little for a radar beam to grab on to. In April 1978, DARPA awarded Northrop a contract for a single flying prototype of the design, which was given the codename TACIT BLUE.
TACIT BLUE performed its initial flight in February 1982, followed by 134 more flights over a three-year evaluation. It was unarguably one of the ugliest aircraft ever built, unflatteringly known as the "Whale". It featured a fuselage resembling a stretched upside-down bathtub with:
TACIT BLUE was highly unstable -- a wind-tunnel model flipped around -- and required a fly-by-wire control system to keep it in the air. TACIT BLUE was powered by twin Garrett ATF3 turbofan engines, used on some business jets, with a take-off thrust of 24.3 kN (2,465 kgp / 5,440 pounds) each. It had a wingspan of 14.7 meters (48 feet 2 inches), a length of 17 meters (55 feet 10 inches), and a weight of 13,605 kilograms (30,000 pounds).
The Hughes surveillance radar carried by TACIT BLUE featured "low probability of intercept (LPI)" operation, with the radar dancing over frequencies and changing pulse patterns so that its signals couldn't be easily picked out of background noise. Apparently the TACIT BLUE program did much to advance LPI radar technology; it would have made absolutely no sense to design a stealthy battlefield surveillance aircraft, and then have it announce its presence by blasting out strong and easily detected radar signals. An LPI radar was also harder to jam or spoof. During test flights, other aircraft never sensed the radar. The radar data was sent to a ground station through a one-way datalink.
Tests with a pole model to check the RCS of TACIT BLUE gave wildly high results, until the test crew discovered an owl had landed on the model. An F-15 fighter tried to track TACIT BLUE on radar and couldn't do it, except if it was within visual range anyway. It was also quiet, the turbofan engines not making much noise.
In 1984, the Army and Air Force decided to collaborate on a non-stealthy battlefield surveillance platform, which would emerge as the E-8 Joint Stars, based on the Boeing 707 airliner. TACIT BLUE was retired and put into storage. It was finally announced to the public in 1996, and put on display in the USAF Museum at Wright Patterson Air Force Base in Ohio a decade later.
* While Northrop was beginning work on TACIT BLUE, back at the Pentagon the top brass were becoming very interested in stealth. In 1977, William "Bill" Perry, Secretary of Defense for the Carter Administration, formed a group to perform studies on the military potential of stealth. The group's conclusion was that improvements in adversary air defenses were threatening to make the current "non-stealthy" US bomber force obsolete. In addition, stealth would allow a single aircraft to make a precision attack on a target, instead of requiring a full "strike package" of multiple bombers, with fighter escorts, jamming platforms, and defense-suppression ("Wild Weasel") aircraft.
The group recommended that two stealthy strike aircraft should be built, an "A Airplane", a fast-track development of the Lockheed HAVE BLUE demonstrator, which would emerge as the F-117; and a "B Airplane" that would be bigger and more capable, but would take more time to roll out.
The B Airplane concept grew over time into a full-blown, long-range heavy bomber. Lockheed had proposals, one apparently being a machine something like a scaled-up F-117 and codenamed SENIOR PEG, but the Pentagon also asked Northrop to investigate. Northrop officials were uneasy about working on a heavy bomber, since the company's last effort along such lines, the XB-35 / YB-49 flying wings of three decades earlier, had come close to financially wrecking the company. They did agree, however, and responded with two proposals -- one of which, cooked up by designer Hal Markarian, took its inspiration from the YB-49. Incidentally, there is a story, possibly true, that the YB-49 had shown a surprising ability to disappear from radar at certain viewing angles.
The proposals were duly submitted in August 1979, and Bill Perry came back with a study contract, asking Northrop to refine the flying wing concept. Waaland joined up with Markarian, and the team also acquired aerodynamicist Hans Grellman, as well as Dick Scherrer, a designer who had recently come over from Lockheed. At the outset, the Northrop "Advanced Strategic Penetration Aircraft (ASPA)", as it was known, was seen strictly as an insurance policy, since Lockheed was regarded by the brass as the front-runner.
However, by the time the Air Force issued a request for an "Advanced Technology Bomber" in September 1980, formalizing the ASPA studies into a program to develop an operational aircraft, Northrop's design was looking much more attractive, and company officials felt they had a shot at winning the contract. Lockheed was partnering with Raytheon on their ATB proposal, and so Northrop approached Boeing to sign up as a partner. Northrop's chairman, Tom Jones, had a meeting with his counterpart at Boeing, Thornton Wilson. Wilson, to his embarrassment, was almost completely ignorant of the ATB program -- but Jones filled him in, and Wilson agreed to join immediately. Witnesses claim that Wilson then turned to one of his people and said: "Don't ever let me be caught in this position again!"
The Northrop concept, codenamed SENIOR ICE, was judged superior to the Lockheed SENIOR PEG proposal, and Northrop won the ATB contract in October 1981. The contract covered delivery of two static-test airframes, one flying prototype, and five evaluation machines. While the Carter Administration had pushed stealth, there had been some ambivalence about production, but the new, hawkish Reagan Administration wanted to go full speed ahead on the ATB. The initial plan envisioned production of 127 ATBs, in addition to the five evaluation machines, which would be brought up to operational specification.
The Pentagon wanted to keep the contract a secret, but Tom Jones pointed out that Northrop had to publicly declare large company contracts in order to be in compliance with securities laws. Government officials, caught by their own regulations, issued the shortest and least informative statement possible about the contract. It would be the last public mention of the program until 1988.
* There was much more work to be done to get such a complicated machine into the air, all the more so because the ATB requirements had expanded over time. Aircraft size and munitions load had grown, and although the ATB was originally seen as a high-altitude penetration machine, the Air Force decided that a low altitude capability would be nice as well -- there was no saying that the Soviets might eventually develop more powerful and smarter radars that could pick up a high-flying stealthy aircraft.
In any case, the work went forward, and the first "B-2" prototype, "Air Vehicle One (AV-1)", was rolled out at the Northrop plant in Palmdale, California, on 22 November 1988. The rollout was public, but observers were restricted to stands that kept them well away from the aircraft and limited their view of it to the front. Although the F-117 had been kept secret for years after its first flight, its test flights had been restricted to night, and that wasn't regarded as acceptable for the B-2. Since it would have been quickly spotted during daylight flights, there was no sense in keeping it a complete secret, and nobody tried.
However, the security restrictions at the rollout weren't completely "airtight", in a highly literal sense of the word. Michael A. Dornheim, a reporter from AVIATION WEEK magazine, flew a light aircraft over the B-2 and had a photographer take pictures, obtaining one of the magazine's biggest scoops of all time, and justifying its nickname of AVIATION LEAK. It was all perfectly legal. The damage, if any, had been done, and the program went forward.
AV-1 performed its first flight on 17 July 1989, flying from Palmdale to Edwards AFB in California. Northrop Test pilot Bruce Hinds and USAF Colonel Richard Couch were at the controls. AV-2, the first of the five evaluation machines, performed its initial flight on 19 October 1990. The first production B-2A was accepted by the US Air Force Air Combat Command (USAF ACC) at Whiteman AFB in Missouri on 17 December 1993. Due to the merger of Northrop and Grumman in the 1990s, the aircraft is now the "Northrop Grumman B-2".
BACK_TO_TOP* As it emerged, the B-2 was "organic" in appearance, a simple flying wing, with absolutely no vertical control surfaces. It had very smooth contours, with few features that could "catch" radar waves and reflect them. It featured a sweepback of 55 degrees, and a zigzag trailing edge. The aircraft was aerodynamically unstable, kept in the air with a quadruple-redundant fly-by-wire (FBW) system, under the control of a General Electric Flight Control Computer (FCC).
The B-2 was designed to be survivable, not merely in penetrating enemy airspace and performing attacks, but in riding out enemy nuclear attacks or counterstrikes. It was thoroughly radiation hardened; Waaland commented that about all that wasn't radiation hardened was the antiskid braking system. It could also operate from dispersed bases, one of the design criteria being the capability to use any airstrip capable of supporting a Boeing 727 airliner. The aerodynamic efficiency of a flying wing allowed use of relatively short runways.
The B-2 made heavy use of titanium for structural elements, with much of the rest of the aircraft built of carbon-reinforced plastic (CRP) material. Large CRP skin assemblies were used to make the aircraft as "seamless" as possible, reducing radar reflections. The principle of seamlessness also meant that the number of access panels was minimized, reversing the trend of the past decades to provide maximum maintenance access. Maintenance access was mostly provided through absolutely essential apertures, such as the bomb bays and crew boarding hatch. There were also no drain holes, with drainage flowing into collectors that were emptied by ground crew.
Designing the CRP assemblies, tooling up for their production, and fitting them in place in aircraft manufacture was a major engineering challenge. Special heat-resistant CRP formulations were used around engine exhausts and other hot spots, where carbon-reinforced epoxy simply wouldn't do. The aircraft was initially coated with a conductive elastomer material to ensure that it had uniform electrical conductivity. This material was not actually RAM, but RAM was used selectively where needed. The B-2 was painted in a bluish-gray anti-reflective paint to reduce its visual signature; it was not painted black, as was the F-117, since the B-2 was expected to perform both daylight and night attacks, and black is a high-visibility color for daylight flight operations.
The leading edge of the wing had an internal structure that helped it absorb radar energy. The outermost wing segment featured a "rudderon" or "deceleron" -- a vertically-split airbrake / rudder that simultaneously opened up and down. To act as an airbrake, both the decelerons were opened, while to act as a rudder, only one was. This clever gimmick went back to the original Northrop flying wings. There was an "elevon" (elevator-aileron) inboard of the deceleron on the outermost segment of each wing, and then two elevons further inboard, on the next segment. Finally, there was a single control surface for pitch control on the "beavertail" at the center end of the aircraft, giving a total of nine control surfaces.
The decelerons had to be opened about five degrees before they were effective, and in normal cruising flight they were left slightly open. However, this undermined stealth, so when the bomber was in hostile airspace, it used differential engine thrust for yaw control.
* The B-2's four General Electric F118-GE-100 non-afterburning bypass turbojets, providing 84.56 kN (8,620 kgp / 19,000 lbf) of thrust each, were derived from the popular GE F110 engine. The F118s were buried in the wings, with two engines clustered together inboard on each wing. An AlliedSignal auxiliary power unit was fitted on the forward end of the left engine assembly for engine starting and ground power. The B-2 also featured a built-in halon engine fire extinguishing system.
The engine intakes and exhausts were on the top of the wings for concealment. The intakes had a zigzag lip to scatter radar reflections, and there was a zigzag slot just before each intake to act as a "boundary layer splitter" -- breaking up the stagnant turbulent airflow that tends to collect on the surface of an aircraft. The inlet ducts were built as an S-curve, and lined with RAM to keep radar reflections off the compressor blades.
The exhaust was mixed with airflow obtained through the boundary layer splitter slot to reduce the infrared signature. The aircraft was also designed to eliminate its contrail, with a tank outboard of the main landing gear to store a chemical that would be mixed with the exhaust flow to suppress the formation of a contrail. This scheme wasn't actually used in practice, with a "lidar" (laser radar) system instead eventually developed to detect formation of a contrail, and alert the pilot to descend to lower altitude. That left an empty bay in each wing, which apparently would never be used.
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NORTHROP GRUMMAN B-2A:
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wingspan:
52.43 meters (172 feet)
wing area:
490.05 sq_meters (5,275 sq_feet)
length:
21.03 meters (69 feet)
height:
5.18 meters (17 feet)
empty weight:
45,400 kilograms (100,000 pounds)
max loaded weight:
181,400 kilograms (400,000 pounds)
maximum speed:
764 KPH (475 MPH / 416 KT)
service ceiling:
+15,240 meters (+50,000 feet)
range:
11,675 kilometers (7,255 MI / 6,310 NMI)
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The B-2 had tricycle landing gear, with twin-wheel nose gear and four-wheel bogey systems for the main gear. The main gear was built by Boeing, being derived from that used on the Boeing 767 airliner. The landing gear doors had stealthy zigzag leading and trailing edges. Since it was difficult to find a place on the smoothly-contoured airframe to paint such "display" items as the aircraft name or serial number, they were painted on the main gear outer doors, making them visible to onlookers when the aircraft was on the ground, or during take-off and landing. There was a boom-refueling port in the center of the back, which was normally covered by doors and popped up when needed.
* The B-2 was fitted with two side-by-side weapons bays that could accommodate a total of 22,680 kilograms (50,000 pounds) of stores. The leading and trailing edges of the weapons bay doors had the classic stealthy zigzag pattern. When the doors were open, twin grilles popped out into the airstream at the front of each weapons bay to ensure proper stores separation. Each of the two weapons bays could be fitted with a Boeing Advanced Rotary Launcher (ARL), capable of carrying eight 1,000-kilogram (2,200-pound) class munitions, or a Bomb Rack Assembly (BRA) for carriage of smaller munitions.
Since the B-2 was originally designed for the strategic bombing role, it was qualified initially for nuclear stores such as the B83 strategic nuclear bomb, with selectable yield in the megaton range, and the smaller B61 "Silver Bullet" nuclear bomb, with selectable yield in the range of hundreds of kilotons. The bomber was later qualified for the penetrating B61-11 penetrating nuclear weapon. A B-2 could carry 16 nuclear stores.
The B-2 was also qualified for use with "dumb" bombs, such as sixteen 900-kilogram (2,000-pound) bombs, or eighty 225-kilogram (500-pound) bombs or cluster munitions based on the Tactical Munitions Dispenser (TMD). However, such stores were likely better carried by other platforms such as the B-52 or B-1B, and so the emphasis with the B-2 was on precision-guided weapons. Some sources have stated it could also carry the AGM-84 Harpoon antiship missile for maritime strike, but it seems more likely that the Harpoon was simply listed as a potential store as a political expedient to emphasize additional roles for the B-2. It is unclear if a B-2 has ever fired a Harpoon.
A Global Positioning System (GPS) guided bomb, the "GPS Aided Munition (GAM)", was developed on a fast-track basis for the B-2, but GAM was strictly an interim fix until the real solution, the "Joint Direct Attack Munition (JDAM)", was introduced in the late 1990s. JDAM was initially a 900-kilogram bomb fitted with gliding strakes and GPS guidance; kits were later introduced for 225-kilogram bombs as well. The B-2 could also carry the AGM-154 Joint Stand-Off Weapon (JSOW) glide bomb, and the AGM-158 Joint Air to Surface Standoff Missile (JASSM).
* The B-2 was highly automated and only required two crew. A centerbody provided crew accommodation, with crew access through a hatch in the belly. The cockpit had large windows -- so large in fact that they tended to make the B-2 look smaller than it really is, though the downward view is poor. Fighter pilots taking the controls of the B-2 say it made them feel like they were "flying in a dumpster". A fine wire mesh was embedded in the windows to block radar signals.
The two crew sat side-by-side on ACES II zero-zero (zero speed, zero altitude) ejection seats, which blasted through frangible roof panels. The "mission commander", who handled navigation and weapons delivery, sat on the left, while the pilot sat on the right. The mission commander was also a rated pilot, and could fly the aircraft if need be. They controlled the aircraft via a "glass cockpit", with each crew using a dashboard featuring four 15-centimeter (6-inch) color CRT multifunction displays (MFDs) and a fighter-style control stick. There was provision for a third seat in case the crew workload proved too high, but a third crewperson proved unnecessary. A chemical toilet and rollup mattress could be carried for long missions. It is unclear if other conveniences were provided, such as a small refrigerator or microwave oven.
The B-2's original "Navigation Sub-System (NSS)" included a Kearfott Inertial Management Unit and a Northrop NAS-26 "Astro-Inertial Unit (AIU)", which obtained position fixes using a telescope to lock on to star positions, using a noticeable port on top of the wing off to the left side of the cockpit. It even worked in daylight when the bomber was at high altitude; it was a descendant of an AIU developed for the SR-71.
The B-2 was fitted with AN/APQ-181 radar, with some similarities to the AN/APG-70 used on the F-15E Strike Eagle fighter. The AN/APQ-181 was a Ku-band (high microwave, from 12 GHz / 3 centimeters to 18 GHz / 2 centimeters) radar, with an electronically steered antenna in the lower leading edge of each wing. The Ku band suffers from greater atmospheric attenuation than lower frequency bands, but it also provides very high resolution for navigation and targeting. The AN/APQ-181 provided LPI operation and 20 modes, including:
Finally, the B-2 included a countermeasures suite, the "Defensive Management System (DMS)", the details of which were generally secret. All the avionics systems were controlled by a total of 13 radiation-hardened "Avionics Control Units (ACUs)" -- run by sophisticated software to help reduce flight load and provide cockpit data display to enhance the crew's "situational awareness".
* After getting up to speed on the B-2, aircrew found the big bomber a very pleasant ride and easy to fly. Its FBW system offloaded a good deal of the work -- and, again, a flying wing is about as aerodynamically clean an aircraft design as could be conceived. The B-2 was an aircraft that wanted to get into the air but didn't want to come back down, and so pilots had to use steep carrier-style landings. Apparently this caused some problems when they went back to more conventional aircraft, and ended up making excessively hard landings.
The aerodynamic cleanliness of the B-2 also made it very responsive to throttle changes. Midair refueling took a little practice, since once the B-2 got into the slipstream of the tanker, the bomber tended to slide forward a bit. The B-2 was very stable, and by the other side of the same coin not particularly maneuverable. B-52 aircrew moving up to the B-2 found ind it more agile than the "Buff", but B-1B aircrew felt the "Bone" was superior in this respect, like a very big fighter, and with its higher wing loading, the B-1B also provided a smoother low-level ride than the B-2. The B-2s systems were complicated and required extensive training to master, but aircrew who grew up on computer games found the systems aspect fun, and no monster to deal with.
Although the official name assigned to the B-2 was "Spirit", the aircrews didn't call it that; apparently it never acquired any particular nickname. However, all the operational B-2s were given SPIRIT OF names, such as SPIRIT OF TEXAS, SPIRIT OF KANSAS, SPIRIT OF CALIFORNIA, and so on. Only one wasn't given a US state in the name: number 82-1066 was, appropriately, named SPIRIT OF HASTINGS. All were based at Whiteman AFB with the USAF 509th Bomb Wing, where they remain today.
BACK_TO_TOP* As mentioned, the Air Force originally planned a total of 132 B-2 bombers as the airborne leg of the nuclear "triad" of bombers, land-based missiles, and submarine-launch missiles that comprise America's nuclear deterrent. In reality, the end of the Cold War meant that the need for new strategic weapons systems had greatly diminished. In addition, the B-2 was a highly advanced aircraft, leading to program glitches, cost escalations, schedule stretchouts, furious political controversies, and repeated cuts in production numbers.
Although the Air Force had accepted the first B-2 in late 1993, the B-2 remained in service test for several more years, not reaching formal initial operational capability until 1997. The USAF only obtained a total of 20 production aircraft. The small production buy meant that the high development costs were spread over a handful of aircraft, and since the program costs were about $48 billion USD, that came to about $2.4 billion USD per aircraft. Had more B-2s been built, of course their incremental cost would have been much less, though still clearly in the hundreds of millions of dollars.
The first ten B-2s delivered to the Air Force, from December 1993 to late 1995, were "Block 10" machines, intended for service evaluation and training. They couldn't fly at full flight loads, lacked precision weapons guidance and terrain following capability, and had a limited DMS. Eight "Block 20" machines were delivered in 1996 and 1997, which were up to operational specification, along with some improvements such as a Global Positioning System (GPS) satellite navigation receiver. The GPS receiver system was integrated into a "GPS-Aided Targeting System (GATS)" to support the GAM GPS-guided bomb, and later the JDAM and other GPS-guided weapons. The ten Block 10s were brought up to Block 20 specification.
The Block 20s were followed by two final new-build "Block 30" aircraft, with the older service machines brought up to the same specification; the AV/1 prototype was also later brought up to Block 30 spec, for a fleet of 21 machines. The Block 30s had avionics improvements, including a satellite communications (SATCOM) link; the lidar contrail-detection system; support for new GPS-guided weapons; and in particular, substantial modifications to improve their stealthiness.
Adding the new stealth features required stripping off all the aircraft's paint and RAM and performing some airframe changes. Stripping off the aircraft's surface layers was tricky, since it had to be done without damaging the composite skin, or resulting in massive amounts of toxic solvents that would be a pain to dispose of properly. Northrop Grumman came up with a scheme in which the aircraft was air-blasted with crystallized wheat starch, a substance that resembles granulated sugar. The starch proved able to remove coatings without damaging the composite skin. Not only was disposal of the starch relatively straightforward, it could be re-used about ten times; in fact, it became more effective after three or four cycles.
* The B-2 went into combat for the first time on the night of 24 March 1999, at the very start of Operation ALLIED FORCE, the NATO air campaign against Serbia. The B-2 dropped JDAM GPS-guided bombs in the opening phases of the campaign to cripple Serbian air defenses so that conventional strike aircraft could operate with greater safety. The B-2 continued to fly strikes against well-defended targets during the rest of the campaign, unfortunately acquiring a bit of notoriety on 7 May 1999 when a B-2 dropped JDAMs on the Chinese embassy in Belgrade. The Chinese government protested loudly and angrily. The blunder was due to bad intelligence and mission planning, not a technical failure or crew error.
Six B-2s were committed to Operation ENDURING FREEDOM, the American intervention in Afghanistan in 2001:2002, performing strikes in the early phases of the conflict. One mission lasted 44 hours, the longest combat sortie in the history of air warfare, with B-2s flying out of Whiteman to Afghanistan, dropping their loads, and then landing on Diego Garcia island in the Indian Ocean to refuel, rearm, and take on new crews while the engines remained on idle. This done, the B-2s went back to Afghanistan to drop their loads, and finally returned to Whiteman. Four B-2s were also committed to Operation IRAQI FREEDOM, the American invasion of Iraq in the spring of 2003.
The first B-2 to be lost was the SPIRIT OF KANSAS, which suffered a take-off accident at Andersen AFB on Guam on 23 February 2008. The two crew were able to eject safely. The particular aircraft had been built in 1989 and had almost 5,200 flight hours on it.
In the meantime, the bomber has continued to be refined. An improved coating scheme, which provided an overall coating of RAM, was developed after the introduction of the Block 30. The new coating scheme not only reduced RCS, but reduced maintenance time per flight hour from 20.8 hours to 9.2 hours. The old scheme used caulk and tape to seal off the radar-reflective edges of access panels. That was not only labor-intensive, but the tape tended to strip off in flight. The improved scheme did not seal off the edges; the RAM coating absorbed RF energy that penetrated into cracks. There has been work on further improved coatings.
Along with the improved coatings, the B-2 has also received new bomb racks that allow it to carry up to 80 GPS-guided weapons of up to 225 kilograms (500 pounds) each -- with a follow-on effort permitting carriage of 40 such munitions, plus four 2,250-kilogram (5,000-pound) GBU-28 "bunker-buster" munitions.
In a particularly significant upgrade, in the summer of 2004, the Air Force awarded a contract under the "Radar Modernization Program (RMP)" for the development of a modernized radar system for the B-2, based on "active electronically scanned array (AESA)" technology. An AESA features an antenna made up of a grid of smart transmit-receive elements that can cooperate to perform functions or perform multiple functions in parallel. There were delays in the program, but the first upgraded B-2 with the new radar went back into service in 2009, with the program completed in 2012.
The new B-2 radar resolved conflicts that existed between the bomber's radar and commercial systems, and allowed the bomber to communicate and exchange target data with other platforms. Maintenance was reduced as well, partly because of the elimination of moving parts. The B-2's defensive management system and radar transponder were also updated as part of the effort.
New stores have been qualified, particularly the little 125-kilogram (250-pound) winged "Small Diameter Bomb II (SDB II)", and the huge 13,100-kilogram (28,900-pound) "Massive Ordnance Penetrator (MOP)" GPS-guided bunker-buster, with the B-2 to carry two MOPs. Other improvements that have been performed, are being implemented, or are planned include:
Of the 20 B-2s currently in service, one is dedicated to tests and trials; typically, about a dozen machines are available for operations. On 18 January 2016, the B-2 returned to war, with two B-2s flying from Whiteman AFB to bomb Islamic State terrorist training camps in Libya, plastering them with 108 225-kilogram JDAMs. The mission took 34 hours, and involved at least five mid-air refuelings. The operating cost of the B-2 is definitely high, so there was some puzzlement as to why the USAF didn't use less expensive bombers like the B-52. There were speculations that the use of the B-2 was as a show of force capability to impress other players, though there were replies that the B-2 could have really been the best aircraft for the mission -- for example, being able to carry far more JDAMs than a B-52.
The Air Force is working on a replacement, the "B-21 Raider", originally the "Long Range Strike Bomber (LRS-B)", to be built by Northrop Grumman. It was first unveiled to the public in late 2022, revealing an aircraft very similar to the B-2, but clearly differing in details -- most significantly, the rear being in a simpler "W" configuration. It will be somewhat smaller, more reconfigurable, and cheaper to buy and fly. It will leverage off operational experience with the B-2, a Northrop Grumman official saying: "What we've learned on B-2 are finding themselves baselined in the design for B-21 for supportability, sustainability, [and] mission capable rate."
The B-21 will go into service no earlier than 2026, with at least 100 to be obtained, and possibly twice that many. The B-2 is currently scheduled to be out of service by 2032, though that date is obviously subject to change.
BACK_TO_TOP* In 1994, the Planes of Fame air museum in Chino, California, restored to flight status the N-9M, one of Jack Northrop's single-seat experimental flying wing prototypes. In February 1995, it flew to Edwards AFB to commemorate the 50th anniversary of its first flight in 1945 by being photographed next to a B-2. B-2 test pilot Bruce Hinds used the opportunity to take the N-9M out for a spin.
I saw a B-2 in flight for the first time at an airshow in Denver in the spring of 2007. That fall, I was on a road trip from Colorado to Florida and made a stop at a zoo near Salina, Kansas. While I was going into the zoo, I saw a sci-fi-looking aircraft near the horizon. I got a zoom shot of it with my camera to confirm that it was a B-2. I was a bit surprised to see it there, but as I drove into Missouri, I went past Whiteman AFB and made the connection.
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v1.0.0 / 01 dec 03 v1.0.1 / 01 oct 05 / Review & polish. v1.0.2 / 01 sep 07 / Review & polish. v1.0.3 / 01 apr 08 / Added crash of SPIRIT OF KANSAS. v1.0.4 / 01 mar 10 / Review & polish. v1.0.5 / 01 feb 12 / Review & polish. v1.0.6 / 01 jan 14 / Review & polish. v1.0.7 / 01 dec 15 / Review & polish. v1.0.8 / 01 nov 17 / Review & polish. v1.0.9 / 01 oct 19 / Review, update, & polish. v1.1.0 / 01 aug 21 / Review, update, & polish. v1.1.1 / 01 aug 23 / Review, update, & polish. (*)BACK_TO_TOP
