View source for Northrop B-2 Spirit

{{short description|American strategic stealth bomber}}
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{{redirect-several|B2}}
{{Use American English|date=July 2019}}
{{Use dmy dates|date=November 2022}}
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{{Infobox aircraft
 |name= B-2 Spirit
 |image= File:B-2 Spirits on Deployment to Indo-Asia-Pacific.jpg
 |image_caption= A U.S. Air Force B-2 Spirit flying over the Pacific Ocean in 2016
 |aircraft_type= [[stealth aircraft|Stealth]] [[Strategic bomber|strategic]] [[heavy bomber]]
 |national_origin= United States
 |manufacturer= [[Northrop Corporation]] <br />[[Northrop Grumman]]
 |first_flight= {{Start date and age|1989|07|17|df=yes}}
 |introduction= 1 January 1997<!--Date the aircraft entered or will enter military or revenue service -->
 |produced= 1987–2000
 |primary_user= [[United States Air Force]]
 |more_users=
 |number_built= 21<ref name=Nat_Museum_B-2_factsheet1>[http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2757 "Northrop B-2A Spirit fact sheet."] {{webarchive|url=https://web.archive.org/web/20080228171308/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2757 |date=28 February 2008}} ''National Museum of the United States Air Force''. Retrieved 13 September 2009.</ref><ref name=USAF_Almanac>Mehuron, Tamar A., Assoc. Editor. [http://www.airforce-magazine.com/MagazineArchive/Magazine%20Documents/2009/May%202009/0509facts_fig.pdf "2009 USAF Almanac, Fact and Figures."] {{Webarchive|url=https://web.archive.org/web/20130113101605/http://www.airforce-magazine.com/MagazineArchive/Magazine%20Documents/2009/May%202009/0509facts_fig.pdf |date=13 January 2013}} ''Air Force Magazine'', May 2009. Retrieved 13 September 2009.</ref>
 |status= In service
 |developed_from=
 |variants=
}}

The '''Northrop B-2 Spirit''', also known as the '''Stealth Bomber''', is an American [[Heavy bomber|heavy]] [[strategic bomber]], featuring low-observable [[stealth aircraft|stealth]] technology designed to [[penetrator (aircraft)|penetrate]] dense [[anti-aircraft warfare|anti-aircraft defenses]]. A [[Subsonic aircraft|subsonic]] [[flying wing]] with a crew of two, the plane was designed by [[Northrop Corporation|Northrop]] (later [[Northrop Grumman]]) as the prime contractor, with [[Boeing]], [[Hughes Aircraft Company|Hughes]], and [[Vought]] as principal subcontractors, and was produced from 1987 to 2000.<ref name="Nat_Museum_B-2_factsheet1" /><ref>Thornborough, A.M.; ''Stealth'', Aircraft Illustrated special, Ian Allan (1991).</ref> The bomber can drop [[conventional weapon|conventional]] and [[thermonuclear weapon]]s,<ref name="Thess">{{Cite web |title=B-2 Spirit |author= |work=[[United States Air Force]] |date= |access-date=14 July 2023 |url=https://www.af.mil/About-Us/Fact-Sheets/Display/Article/104482/b-2-spirit/ |archive-date=25 June 2023 |archive-url=https://web.archive.org/web/20230625025242/https://www.af.mil/About-Us/Fact-Sheets/Display/Article/104482/b-2-spirit/ |url-status=live}}</ref> such as up to eighty {{convert|500|lb|kg|adj=mid| class}} [[Mark 82 bomb|Mk 82]] [[Joint Direct Attack Munition|JDAM]] [[Global Positioning System|GPS]]-guided bombs, or sixteen {{convert|2400|lb|kg|adj=on}} [[B83 nuclear bomb]]s. The B-2 is the only acknowledged in-service aircraft that can carry large [[air-to-surface missile|air-to-surface]] [[Standoff missile|standoff weapon]]s in a stealth configuration.

Development began under the Advanced Technology Bomber (ATB) project during the [[Presidency of Jimmy Carter|Carter administration]], which cancelled the Mach 2-capable [[Rockwell B-1 Lancer#B-1A program|B-1A bomber]] in part because the ATB showed such promise. But development difficulties delayed progress and drove up costs. Ultimately, the program produced 21 B-2s at an average cost of $2.13&nbsp;billion (~${{Inflation|US|2.13|1997|r=2}}&nbsp;billion in {{Inflation/year|US}}), including development, engineering, testing, production, and procurement.<ref name="Gao" /> Building each aircraft cost an average of US$737&nbsp;million,<ref name=Gao>[https://www.gpo.gov/fdsys/pkg/GAOREPORTS-NSIAD-97-181/pdf/GAOREPORTS-NSIAD-97-181.pdf "B-2 Bomber: Cost and Operational Issues Letter Report, GAO/NSIAD-97-181."] {{Webarchive|url=https://web.archive.org/web/20170322100929/https://www.gpo.gov/fdsys/pkg/GAOREPORTS-NSIAD-97-181/pdf/GAOREPORTS-NSIAD-97-181.pdf |date=22 March 2017}} ''United States General Accounting Office'' (GAO), 14 August 1997. Retrieved 13 December 2018.</ref> while total [[procurement]] costs (including production, [[spare part]]s, equipment, [[retrofitting]], and software support) averaged $929&nbsp;million (~${{Format price|{{Inflation|index=US-GDP|value=929000000|start_year=2018}}}} in {{Inflation/year|US-GDP}}) per plane.<ref name=Gao/> The [[megaproject|project]]'s considerable [[Capital cost|capital]] and [[operating cost]]s made it controversial in the [[United States Congress|U.S. Congress]] even before the winding down of the [[Cold War]] dramatically reduced the desire for a stealth aircraft designed to strike deep in Soviet territory. Consequently, in the late 1980s and 1990s lawmakers shrank the planned purchase of 132 bombers to 21.

The B-2 can perform attack missions at altitudes of up to {{convert|50000|ft|m}}; it has an unrefueled range of more than {{convert|6000|nmi|mi km}} and can fly more than {{convert|10000|nmi|mi km}} with one [[aerial refueling|midair refueling]]. It entered service in 1997 as the second aircraft designed with advanced stealth technology, after the [[Lockheed F-117 Nighthawk]] attack aircraft. Primarily designed as a nuclear bomber, the B-2 was first used in combat to drop conventional, non-nuclear [[aircraft ordnance|ordnance]] in the [[Kosovo War]] in 1999. It was later used in [[Iraq War|Iraq]], [[War in Afghanistan (2001–2021)|Afghanistan]], [[Libyan Civil War (2011)|Libya]] and [[Operation Prosperity Guardian|Yemen]].<ref name="B-2_AF_fact_sheet" /><ref name=":0" />

The [[United States Air Force]] has nineteen B-2s in service as of 2024;<ref name="airforcemag13may24">[https://www.airandspaceforces.com/damaged-b-2-retire-not-repair/ "USAF Will Retire, Not Repair, Damaged B-2; Fleet Shrinking to 19 Aircraft"]. ''Air & Space Forces Magazine''. 13 May 2024.</ref> one was destroyed in [[2008 Andersen Air Force Base B-2 accident|a 2008 crash]]<ref>Rolfsen, Bruce. [http://www.airforcetimes.com/news/2008/06/airforce_b2_crashreport_060508w/ "Moisture confused sensors in B-2 crash."] ''Air Force Times'', 9 June 2008. Retrieved 13 September 2009.</ref> and another one damaged in a crash in 2022 was retired from service likely on account of the cost and duration of a potential repair.<ref name="airforcemag13may24"/> The Air Force plans to operate the B-2s until 2032, when the [[Northrop Grumman B-21 Raider]] is to replace them.<ref name="airforcetimes11feb18">{{Cite web |last=admin |date=2018-02-09 |title=USAF to Retire B-1, B-2 in Early 2030s as B-21 Comes On-Line |url=https://www.airandspaceforces.com/usaf-to-retire-b-1-b-2-in-early-2030s-as-b-21-comes-on-line/ |access-date=2022-12-17 |website=Air & Space Forces Magazine |language=en-US |archive-date=17 December 2022 |archive-url=https://web.archive.org/web/20221217052514/https://www.airandspaceforces.com/usaf-to-retire-b-1-b-2-in-early-2030s-as-b-21-comes-on-line/ |url-status=live}}</ref>

==Development==

===Origins===
By the mid-1970s, military aircraft designers had learned of a new method to avoid missiles and interceptors, known today as "[[Stealth aircraft|stealth]]". The concept was to build an aircraft with an [[airframe]] that deflected or absorbed [[radar]] signals so that little was reflected back to the radar unit. An aircraft having radar stealth characteristics would be able to fly nearly undetected and could be attacked only by weapons and systems not relying on radar. Although other detection measures existed, such as human observation, [[Infrared search and track|infrared scanners]], and [[Acoustic location|acoustic locators]], their relatively short detection range or poorly developed technology allowed most aircraft to fly undetected, or at least untracked, especially at night.<ref>Rao, G.A. and S.P. Mahulikar. "Integrated review of stealth technology and its role in airpower". ''Aeronautical Journal'', v. 106 (1066), 2002, pp. 629–641.</ref>

In 1974, [[DARPA]] requested information from U.S. aviation firms about the largest [[radar cross-section]] of an aircraft that would remain effectively invisible to radars.<ref>Crickmore and Crickmore 2003, p. 9.</ref> Initially, [[Northrop Corporation|Northrop]] and [[McDonnell Douglas]] were selected for further development. [[Lockheed Corporation|Lockheed]] had experience in this field with the development of the [[Lockheed A-12]] and [[Lockheed SR-71 Blackbird|SR-71]], which included several stealthy features, notably its canted vertical stabilizers, the use of composite materials in key locations, and the overall surface finish in [[Radiation-absorbent material|radar-absorbing paint]]. A key improvement was the introduction of computer models used to predict the radar reflections from flat surfaces where collected data drove the design of a "faceted" aircraft. Development of the first such designs started in 1975 with the ''[[Lockheed Have Blue|Have Blue]]'', a model Lockheed built to test the concept.<ref>[http://www.centennialofflight.gov/essay/Evolution_of_Technology/Stealth_aircraft/Tech31.htm "Stealth Aircraft."] {{webarchive|url=https://web.archive.org/web/20110721035221/http://www.centennialofflight.gov/essay/Evolution_of_Technology/Stealth_aircraft/Tech31.htm |date=21 July 2011}} ''U.S. Centennial of Flight Commission'', 2003. Retrieved 5 November 2012.</ref>

Plans were well advanced by the summer of 1975, when [[DARPA]] started the Experimental Survivability Testbed project. Northrop and Lockheed were awarded contracts in the first round of testing. Lockheed received the sole award for the second test round in April 1976 leading to the ''Have Blue'' program and eventually the [[F-117]] stealth attack aircraft.<ref>{{harvnb|Griffin|Kinnu|2007|pp=14–15}}</ref> Northrop also had a classified technology demonstration aircraft, the [[Northrop Tacit Blue|Tacit Blue]] in development in 1979 at [[Area 51]]. It developed stealth technology, LO (low observables), [[fly-by-wire]], curved surfaces, composite materials, [[Signals intelligence|electronic intelligence]], and Battlefield Surveillance Aircraft Experimental. The stealth technology developed from the program was later incorporated into other operational aircraft designs, including the B-2 stealth bomber.<ref>''The integrator'', Northrop Grumman (newspaper), Vol. 8, No. 12; 30 June 2006, p. 8. author: Carol Ilten.</ref>

===ATB program===
By 1976, these programs had progressed to a position in which a long-range strategic stealth bomber appeared viable. President [[Jimmy Carter]] became aware of these developments during 1977, and it appears to have been one of the major reasons the B-1 was canceled.<ref>{{harvnb|Withington|2006|p=7}}</ref> Further studies were ordered in early 1978, by which point the ''Have Blue'' platform had flown and proven the concepts. During the [[1980 United States presidential election|1980 presidential election]] campaign in 1979, [[Ronald Reagan]] repeatedly stated that Carter was weak on defense and used the B-1 as a prime example. In response, on 22 August 1980 the [[Carter administration]] publicly disclosed that the [[United States Department of Defense]] was working to develop stealth aircraft, including a bomber.<ref name=goodall>Goodall 1992, {{page needed|date=August 2012}}</ref>

[[File:B2 bomber initial rollout ceremony 1988.jpg|thumb|left|The B-2's first public display in 1988 at Palmdale, California: in front of the B-2 is a star shape formed with five B-2 silhouettes|alt=Front view of tailless aircraft parked in front of building. On the building face is a blue and red rectangular flag. A star-shaped artwork is on the taxiway in front of aircraft.]]
The Advanced Technology Bomber (ATB) program began in 1979.<ref name=Pace_p20-27>{{harvnb|Pace|1999|pp=20–27}}</ref> Full development of the [[black project]] followed, funded under the code name "[[Aurora (aircraft)|Aurora]]".<ref name=Rich/> After the evaluations of the companies' proposals, the ATB competition was narrowed to the Northrop/[[Boeing]] and Lockheed/[[Rockwell International|Rockwell]] teams with each receiving a study contract for further work.<ref name="Pace_p20-27" /> Both teams used [[flying wing]] designs.<ref name="Rich" /> The Northrop proposal was code named "Senior Ice", and the Lockheed proposal code named "[[Lockheed Senior Peg|Senior Peg]]".<ref>{{cite web|url=http://www.joebaugher.com/usaf_bombers/newb2_1.html|title=Northrop B-2A Spirit|website=joebaugher.com|access-date=12 January 2015|archive-date=20 January 2018|archive-url=https://web.archive.org/web/20180120041317/http://www.joebaugher.com/usaf_bombers/newb2_1.html|url-status=live}}</ref> Northrop had prior experience developing the [[Northrop YB-35|YB-35]] and [[Northrop YB-49|YB-49]] flying wing aircraft.<ref>{{harvnb|Donald|2003|p=13}}</ref> The Northrop design was larger while the Lockheed design included a small tail.<ref name=Rich>{{harvnb|Rich|Janos|1996}}{{page needed|date=August 2012}}</ref> In 1979, designer [[Hal Markarian]] produced a sketch of the aircraft that bore considerable similarities to the final design.<ref>Sweetman 1991, pp. 21, 30.</ref> The USAF originally planned to procure 165 ATB bombers.<ref name="Nat_Museum_B-2_factsheet1"/>

The Northrop team's ATB design was selected over the Lockheed/Rockwell design on 20 October 1981.<ref name=Pace_p20-27/><ref name=Spick_p339>{{harvnb|Spick|2000|p=339}}</ref> The Northrop design received the designation B-2 and the name "Spirit". The bomber's design was changed in the mid-1980s when the 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 US$1&nbsp;billion to the program's cost.<ref name=goodall/> An estimated US$23&nbsp;billion was secretly spent for [[research and development]] on the B-2 by 1989.<ref>Van Voorst, Bruce. [https://web.archive.org/web/20090821005144/http://www.time.com/time/magazine/article/0,9171,958256,00.html?promoid=googlep "The Stealth Takes Wing."] ''Time'', 31 July 1989. Retrieved 13 September 2009.</ref> [[Massachusetts Institute of Technology|MIT]] engineers and scientists helped assess the mission effectiveness of the aircraft under a five-year [[Classified information|classified]] contract during the 1980s.<ref>{{harvnb|Griffin|Kinnu|2007|pp=ii–v}}</ref> Northrop was the B-2's prime contractor; major subcontractors included [[Boeing Integrated Defense Systems|Boeing]], [[Hughes Aircraft]] (now [[Raytheon]]), [[GE Aviation|GE]], and [[Vought Aircraft Industries|Vought Aircraft]].<ref name="B-2_AF_fact_sheet" />

===Secrecy and espionage===
[[File:B-2 first flight 071201-F-9999J-034.jpg|thumb|right|The B-2's first public flight in 1989|alt=Top view of triangular aircraft, with sawtooth trailing edge, in flight over desert]]

During its design and development, the Northrop B-2 program was a [[black project]]; all program personnel needed a secret clearance.<ref>{{cite AV media|url=https://www.youtube.com/watch?v=mzQPIlXe2H0|title=YouTube|via=YouTube|access-date=5 February 2015|archive-url=https://web.archive.org/web/20150712052753/https://www.youtube.com/watch?v=mzQPIlXe2H0|archive-date=12 July 2015|url-status=dead}}</ref> Still, it was less closely held than the Lockheed F-117 program; more people in the federal government knew about the B-2, and more information about the project was available. Both during development and in service, considerable effort has been devoted to maintaining the security of the B-2's design and technologies. Staff working on the B-2 in most, if not all, capacities need a level of special-access clearance and undergo extensive background checks carried out by a special branch of the USAF.<ref>Vartaebedian, Ralph. [https://pqasb.pqarchiver.com/latimes/access/6359225.html?dids=6359225:6359225&FMT=ABS&FMTS=ABS:FT&type=current&date=Feb+16%2C+1993&author=Vartaebedian%2C+Ralph&pub=Los+Angeles+Times&desc=Defense+worker+loses+job+over+his+ties+to+India&pqatl=google "Defense worker loses job over his ties to India".] {{Webarchive|url=https://web.archive.org/web/20121107225049/http://pqasb.pqarchiver.com/latimes/access/6359225.html?dids=6359225:6359225&FMT=ABS&FMTS=ABS:FT&type=current&date=Feb+16%2C+1993&author=Vartaebedian%2C+Ralph&pub=Los+Angeles+Times&desc=Defense+worker+loses+job+over+his+ties+to+India&pqatl=google |date=7 November 2012}} ''Los Angeles Times'', 16 February 1993.</ref>

A former Ford automobile assembly plant in [[Pico Rivera, California]], was acquired and heavily rebuilt; the plant's employees were sworn to secrecy. To avoid suspicion, components were typically purchased through [[front company|front companies]], military officials would visit out of uniform, and staff members were routinely subjected to [[polygraph]] examinations. Nearly all information on the program was kept from the [[Government Accountability Office]] (GAO) and members of Congress until the mid-1980s.<ref>Atkinson, Rick. [https://web.archive.org/web/20130516030051/http://www.highbeam.com/doc/1P2-1216253.html "Unraveling Stealth's 'Black World';Questions of Cost and Mission Arise Amid Debate Over Secrecy Series: Project Senior C.J.; The Story Behind The B-2 Bomber Series Number: 2/3."] ''The Washington Post'', 9 October 1989.</ref>

The B-2 was first publicly displayed on 22 November 1988 at [[United States Air Force Plant 42]] in [[Palmdale, California]], where it was assembled. This viewing was heavily restricted, and guests were not allowed to see the rear of the B-2. However, ''[[Aviation Week & Space Technology|Aviation Week]]'' editors found that there were no airspace restrictions above the presentation area and took aerial photographs of the aircraft's secret rear section<ref name="Pace_p29-36" /> with suppressed engine exhausts.<ref>{{Cite web |last=Norris |first=Guy |date=2022-12-02 |title=The Story Behind Aviation Week's B-2 Rollout Photo Scoop |url=https://aviationweek.com/defense-space/aircraft-propulsion/story-behind-aviation-weeks-b-2-rollout-photo-scoop |access-date= |website=aviationweek.com}}</ref> The B-2's (s/n {{USAF serial|82|1066}} / AV-1) first public flight was on 17 July 1989 from Palmdale to [[Edwards Air Force Base]].<ref name="Pace_p29-36">Pace 1999, pp. 29–36.</ref>

In 1984, Northrop employee [[Thomas Patrick Cavanagh]] was arrested for attempting to sell classified information from the Pico Rivera factory to the [[Soviet Union]].<ref>AP. [https://query.nytimes.com/gst/fullpage.html?res=9B0DE1DB1231F937A15755C0A961948260 "Stealth bomber classified documents missing."] {{Webarchive|url=https://web.archive.org/web/20220815025039/https://www.nytimes.com/1987/06/24/us/no-headline-844687.html |date=15 August 2022}} ''The New York Times'', 24 June 1987. Retrieved 13 September 2009.</ref> Cavanagh was sentenced to life in prison in 1985 but released on parole in 2001.<ref>{{cite web|url=https://www.bop.gov/inmateloc/|title=Thomas Patrick Cavanaugh|work=Locate a Federal Inmate|publisher=Federal Bureau of Prisons|access-date=5 September 2023|archive-date=29 January 2014|archive-url=https://web.archive.org/web/20140129150019/https://www.bop.gov/inmateloc/|url-status=live}}</ref> In October 2005, [[Noshir Gowadia]], a design engineer who worked on the B-2's propulsion system, was arrested for selling classified information to China.<ref>[https://web.archive.org/web/20070222093416/http://honolulu.fbi.gov/pressrel/2005/goodwin102605.htm "Press Release."] ''FBI Honolulu''. Retrieved:: 1 December 2010.</ref> Gowadia was convicted and sentenced to 32 years in prison.<ref>Foster, Peter. [https://www.telegraph.co.uk/news/worldnews/northamerica/usa/8280233/Engineer-jailed-for-selling-US-stealth-bomber-technology-to-China.html "Engineer jailed for selling US stealth bomber technology to China."] {{Webarchive|url=https://web.archive.org/web/20170703142231/http://www.telegraph.co.uk/news/worldnews/northamerica/usa/8280233/Engineer-jailed-for-selling-US-stealth-bomber-technology-to-China.html |date=3 July 2017}} ''The Telegram'', 24 January 2011.</ref>

===Program costs and procurement===
A procurement of 132 aircraft was planned in the mid-1980s but was later reduced to 75.<ref name=Pace_p75-76>{{harvnb|Pace|1999|pp=75–76}}</ref> By the early 1990s the [[Dissolution of the Soviet Union|Soviet Union dissolved]], effectively eliminating the Spirit's primary [[Cold War]] mission. Under budgetary pressures and Congressional opposition, in his 1992 [[State of the Union]] address, President [[George H. W. Bush]] announced B-2 production would be limited to 20 aircraft.<ref>[http://www.c-span.org/executive/transcript.asp?cat=current_event&code=bush_admin&year=1992 "President George H. Bush's State of the Union Address."] ''c-span.org'', 28 January 1992. Retrieved 13 September 2009. {{webarchive |url=https://web.archive.org/web/20100824040054/http://www.c-span.org/executive/transcript.asp?cat=current_event&code=bush_admin&year=1992 |date=24 August 2010}}</ref> In 1996, however, the [[Presidency of Bill Clinton|Clinton administration]], though originally committed to ending production of the bombers at 20 aircraft, authorized the conversion of a 21st bomber, a [[prototype]] test model, to Block 30 fully operational status at a cost of nearly $500&nbsp;million (~${{Format price|{{Inflation|index=US-GDP|value=500000000|start_year=1996}}}} in {{Inflation/year|US-GDP}}).<ref>Graham, Bradley. "US to add one B-2 plane to 20 plane fleet." ''The Washington Post'', 22 March 1996, p. A20.</ref> In 1995, Northrop made a proposal to the USAF to build 20 additional aircraft with a [[flyaway cost]] of $566&nbsp;million each.<ref name=Ency_Mod_Mil>Eden 2004, pp. 350–353.</ref>

The program was the subject of public controversy for its cost to American taxpayers. In 1996, the GAO disclosed that the USAF's B-2 bombers "will be, by far, the costliest bombers to operate on a per aircraft basis", costing over three times as much as the [[Rockwell B-1 Lancer|B-1B]] (US$9.6&nbsp;million annually) and over four times as much as the B-52H (US$6.8&nbsp;million annually). In September 1997, each hour of B-2 flight necessitated 119 hours of maintenance. Comparable maintenance needs for the B-52 and the B-1B are 53 and 60 hours, respectively, for each hour of flight. A key reason for this cost is the provision of air-conditioned hangars large enough for the bomber's {{convert|172|ft|m|abbr=on}} wingspan, which are needed to maintain the aircraft's stealth properties, particularly its "low-observable" stealth skins.<ref>Capaccio, Tony. "The B-2's Stealthy Skins Need Tender, Lengthy Care." ''Defense Week'', 27 May 1997, p. 1.</ref><ref>''US General Accounting Office'' September 1996, pp. 53, 56.</ref> Maintenance costs are about $3.4&nbsp;million per month for each aircraft.<ref>[http://www.strategypage.com/htmw/htairfo/articles/20100614.aspx "The Gold Plated Hangar Queen Survives."] {{Webarchive|url=https://web.archive.org/web/20100617041312/http://www.strategypage.com/htmw/htairfo/articles/20100614.aspx |date=17 June 2010}} ''Strategyworld.com'', 14 June 2010. Retrieved 8 April 2011.</ref> An August 1995 GAO report disclosed that the B-2 had trouble operating in heavy rain, as rain could damage the aircraft's stealth coating, causing procurement delays until an adequate protective coating could be found. In addition, the B-2's terrain-following/terrain-avoidance radar had difficulty distinguishing rain from other obstacles, rendering the subsystem inoperable during rain.<ref>Murphy, Robert D., Michael J. Hazard, Jeffrey T. Hunter, and James F. Dinwiddie. ''B-2 Bomber: Status of Cost, Development, and Production''. No. GAO/NSIAD-95-164. General Accounting Office Washington, DC. National Security and International Affairs Division. August 1995, pp. 16, 20</ref> However a subsequent report in October 1996 noted that the USAF had made some progress in resolving the issues with the radar via software fixes and hoped to have these fixes undergoing tests by the spring of 1997.<ref>''US General Accounting Office'', October 1996, pp. 4, 23</ref>

The total "military construction" cost related to the program was projected to be US$553.6&nbsp;million in 1997 dollars. The cost to procure each B-2 was US$737&nbsp;million in 1997 dollars (equivalent to US${{inflation|US-GDP|0.737|1997|r=3}}&nbsp;billion in 2021{{Inflation/fn|US-GDP}}), based only on a fleet cost of US$15.48&nbsp;billion.<ref name=Gao/> The procurement cost per aircraft, as detailed in GAO reports, which include spare parts and software support, was $929&nbsp;million per aircraft in 1997 dollars.<ref name=Gao/>

The total program cost projected through 2004 was US$44.75&nbsp;billion in 1997 dollars (equivalent to US${{inflation|US-GDP|44.75|1997}}&nbsp;billion in 2021{{Inflation/fn|US-GDP}}). This includes development, procurement, facilities, construction, and spare parts. The total program cost averaged US$2.13&nbsp;billion per aircraft.<ref name=Gao/> The B-2 may cost up to $135,000 per flight hour to operate in 2010, which is about twice that of the B-52 and B-1.<ref name="axe20120326">Axe, David. [https://www.theatlantic.com/national/archive/2012/03/why-cant-the-air-force-build-an-affordable-plane/254998/ "Why Can't the Air Force Build an Affordable Plane?"] {{Webarchive|url=https://web.archive.org/web/20170423153606/https://www.theatlantic.com/national/archive/2012/03/why-cant-the-air-force-build-an-affordable-plane/254998/ |date=23 April 2017}} ''The Atlantic'', 26 March 2012. Retrieved 30 June 2012.</ref><ref name="FlightglobalUSAirForceCombatFleetsTrueOperationalCostsRevealed">{{cite news|last1=Trimble|first1=Stephen|title=US Air Force combat fleet's true operational costs revealed|url=http://www.flightglobal.com/blogs/the-dewline/2011/08/exclusive-us-air-force-combat.html|url-status=dead|access-date=1 July 2012|work=The DEW Line|date=26 August 2011|archive-url=https://web.archive.org/web/20121020092809/http://www.flightglobal.com/blogs/the-dewline/2011/08/exclusive-us-air-force-combat.html|archive-date=20 October 2012}}</ref>

===Opposition===
In its consideration of the fiscal year 1990 defense budget, the House Armed Services Committee trimmed $800&nbsp;million from the B-2 research and development budget, while at the same time staving off a motion to end the project. Opposition in committee and in Congress was mostly broad and bipartisan, with Congressmen [[Ron Dellums]] (D-CA), [[John Kasich]] (R-OH), and [[John G. Rowland]] (R-CT) authorizing the motion to end the project—as well as others in the Senate, including [[Jim Exon]] (D-NE) and [[John McCain]] (R-AZ) also opposing the project.<ref name=Schmitt>Schmitt, Eric. [https://www.nytimes.com/1991/09/14/us/key-senate-backer-of-stealth-bomber-sees-it-in-jeopardy.html?pagewanted=1 "Key Senate Backer of Stealth Bomber Sees It in Jeopardy."] {{Webarchive|url=https://web.archive.org/web/20160306122801/http://www.nytimes.com/1991/09/14/us/key-senate-backer-of-stealth-bomber-sees-it-in-jeopardy.html?pagewanted=1 |date=6 March 2016}} ''The New York Times'', 14 September 1991. Retrieved 23 July 2009.</ref> Dellums and Kasich, in particular, worked together from 1989 through the early 1990s to limit production to 21 aircraft and were ultimately successful.<ref>{{cite web |last1=Torry |first1=Jack |last2=Wehrman |first2=Jessica |title=Kasich still touts opposition to stealth bomber |url=https://www.dispatch.com/article/20150706/NEWS/307069768 |work=Columbus Dispatch |access-date=13 April 2020 |date=6 July 2015 |archive-date=25 October 2020 |archive-url=https://web.archive.org/web/20201025031202/https://www.dispatch.com/article/20150706/NEWS/307069768 |url-status=live}}</ref>

The escalating cost of the B-2 program and evidence of flaws in the aircraft's ability to elude detection by radar<ref name=Schmitt/> were among factors that drove opposition to continue the program. At the peak production period specified in 1989, the schedule called for spending US$7&nbsp;billion to $8&nbsp;billion per year in 1989 dollars, something Committee Chair [[Les Aspin]] (D-WI) said "won't fly financially".<ref name=Sorenson_p168>{{harvnb|Sorenson|1995|p=168}}</ref> In 1990, the Department of Defense accused Northrop of using faulty components in the [[Aircraft flight control system|flight control system]]; it was also found that redesign work was required to reduce the risk of damage to engine fan blades by bird ingestion.<ref>"Moisture in sensors led to stealth bomber crash, Air Force report says." ''Kansas City Star'', 5 June 2008.</ref>

In time, several prominent members of Congress began to oppose the program's expansion, including Senator [[John Kerry]] (D-MA), who cast votes against the B-2 in 1989, 1991, and 1992. By 1992, Bush had called for the cancellation of the B-2 and promised to cut military spending by 30% in the wake of the collapse of the Soviet Union.<ref>[http://www.factcheck.org/zell_millers_attack_on_kerry_a_little.html "Zell Miller's Attack on Kerry: A Little Out Of Date."] {{webarchive|url=https://web.archive.org/web/20070714102157/http://www.factcheck.org/zell_millers_attack_on_kerry_a_little.html |date=14 July 2007}} ''FactCheck.org'', 4 October 2004. Retrieved 26 October 2004.</ref> In October 1995, former [[Chief of Staff of the United States Air Force]], [[Michael E. Ryan|General Mike Ryan]], and former chairman of the Joint Chiefs of Staff, General [[John Shalikashvili]], strongly recommended against Congressional action to fund the purchase of any additional B-2s, arguing that to do so would require unacceptable cuts in existing conventional and nuclear-capable aircraft,<ref>Bender, Brian and John Robinson. "More Stealth Bombers Mean Less Combat Power". ''Defense Daily'', 5 August 1997, p. 206.</ref> and that the military had greater priorities in spending a limited budget.<ref>''US General Accounting Office'' September 1996, p. 70.</ref>

Some B-2 advocates argued that procuring twenty additional aircraft would save money because B-2s would be able to deeply penetrate anti-aircraft defenses and use low-cost, short-range attack weapons rather than expensive standoff weapons. However, in 1995, the [[Congressional Budget Office]] (CBO) and its Director of National Security Analysis found that additional B-2s would reduce the cost of expended munitions by less than US$2&nbsp;billion in 1995 dollars during the first two weeks of a conflict, in which the USAF predicted bombers would make their greatest contribution; this was a small fraction of the US$26.8&nbsp;billion (in 1995 dollars) life cycle cost that the CBO projected for an additional 20 B-2s.<ref>''US General Accounting Office'' September 1996, p. 72.</ref>

In 1997, as [[Ranking Member]] of the [[U.S. House Committee on Armed Services|House Armed Services Committee]] and National Security Committee, Congressman [[Ron Dellums]] (D-CA), a long-time opponent of the bomber, cited five independent studies and offered an amendment to that year's defense authorization bill to cap production of the bombers to the existing 21 aircraft; the amendment was narrowly defeated.<ref name=Amendment>[https://fas.org/nuke/guide/usa/bomber/970623-b2.htm "Debate on Dellums Amendment to 1998 Defense Authorization Act."] {{Webarchive|url=https://web.archive.org/web/20150409000713/https://fas.org/nuke/guide/usa/bomber/970623-b2.htm |date=9 April 2015}} ''fas.org'', 23 June 1997.</ref> Nonetheless, Congress did not approve funding for additional B-2s.

===Further developments===
Several upgrade packages have been applied to the B-2. In July 2008, the B-2's onboard computing architecture was extensively redesigned; it now incorporates a new integrated [[Processor (computing)|processing unit]] that communicates with systems throughout the aircraft via a newly installed [[fiber optic]] network; a new version of the operational flight program software was also developed, with [[legacy code]] converted from the [[JOVIAL]] programming language to standard [[C (programming language)|C]].<ref>McKinney, Brooks. [http://www.irconnect.com/noc/press/pages/news_releases.html?d=145810 "Air Force Completes Preliminary Design Review of New B-2 Bomber Computer Architecture."] {{webarchive|url=https://web.archive.org/web/20100521002050/http://www.irconnect.com/noc/press/pages/news_releases.html?d=145810 |date=21 May 2010}} ''Northrop Grumman'', 7 July 2008. Retrieved 8 June 2011.</ref><ref>[http://www.semanticdesigns.com/Products/Services/NorthropGrummanB2.html "Semantic Designs Aligns with Northrop Grumman to Modernize B-2 Spirit Bomber Software Systems"] {{Webarchive|url=https://web.archive.org/web/20180909005707/http://www.semanticdesigns.com/Products/Services/NorthropGrummanB2.html |date=9 September 2018}}. ''Semantic Designs''. Retrieved 8 June 2011.</ref> Updates were also made to the weapon control systems to enable strikes upon moving targets, such as ground vehicles.<ref>McKinney, Brooks. [http://www.defense-aerospace.com/articles-view/release/3/90827/b_2-upgrade-adds-mobile-target-engagement.html "Northrop Grumman Adding Mobile Targets to B-2 Bomber Capabilities."] {{Webarchive|url=https://web.archive.org/web/20180812052653/http://www.defense-aerospace.com/articles-view/release/3/90827/b_2-upgrade-adds-mobile-target-engagement.html |date=12 August 2018}} ''Northrop Grumman'', 7 February 2008. Retrieved 29 October 2009.</ref>

[[File:B2 silhouette.JPG|thumb|B-2 from below]]
On 29 December 2008, USAF officials awarded a US$468&nbsp;million contract to Northrop Grumman to modernize the B-2 fleet's radars.<ref>[https://web.archive.org/web/20081231215947/http://www.af.mil/news/story.asp?id=123129776 "B-2 radar modernization program contract awarded."] ''US Air Force'', 30 December 2008. Retrieved 13 September 2009.</ref> Changing the radar's frequency was required as the [[United States Department of Commerce]] had sold that radio spectrum to another operator.<ref>Warwick, Graham. [http://www.aviationweek.com/aw/generic/story.jsp?id=news/UPGR12308.xml&headline=USAF%20Awards%20B-2%20Radar%20Upgrade%20Production&channel=defense "USAF Awards B-2 Radar Upgrade Production."]{{Dead link|date=September 2023 |bot=InternetArchiveBot |fix-attempted=yes}} ''Aviation Week'', 30 December 2008. Retrieved 13 September 2009.</ref> In July 2009, it was reported that the B-2 had successfully passed a major USAF audit.<ref>Jennings, Gareth. [http://www.janes.com/news/defence/jdw/jdw090724_2_n.shtml "B-2 passes modernisation milestones."] {{Webarchive|url=https://web.archive.org/web/20090731232154/http://www.janes.com/news/defence/jdw/jdw090724_2_n.shtml |date=31 July 2009}} ''Janes'', 24 July 2009. Retrieved 13 September 2009.</ref> In 2010, it was made public that the [[Air Force Research Laboratory]] had developed a new material to be used on the part of the wing trailing edge subject to engine exhaust, replacing existing material that quickly degraded.<ref>[http://defense-update.com/wp/20101119_b2_hte.html "New Composite to Improve B-2 Durability."] ''Defense-Update'', 19 November 2010. {{webarchive |url=https://web.archive.org/web/20101128213955/http://defense-update.com/wp/20101119_b2_hte.html |date=28 November 2010}}</ref>

In July 2010, political analyst Rebecca Grant speculated that when the B-2 becomes unable to reliably penetrate enemy defenses, the [[Lockheed Martin F-35 Lightning II]] may take on its strike/[[Air interdiction|interdiction]] mission, carrying [[B61 nuclear bomb]]s as a tactical bomber.<ref>Grant, Rebecca. [http://www.airforce-magazine.com/MagazineArchive/Pages/2010/July%202010/0710nato.aspx "Nukes for NATO."] {{Webarchive|url=https://web.archive.org/web/20101207023456/http://www.airforce-magazine.com/MagazineArchive/Pages/2010/July%202010/0710nato.aspx |date=7 December 2010}} ''Air Force Magazine'', July 2010.</ref> However, in March 2012, [[The Pentagon]] announced that a $2&nbsp;billion, 10-year-long modernization of the B-2 fleet was to begin. The main area of improvement would be replacement of outdated avionics and equipment.<ref name="kelley insider">Kelley, Michael. [http://articles.businessinsider.com/2012-03-28/news/31247799_1_b-2s-whiteman-air-force-base-stealth-bombers "The Air Force Announced It's Upgrading The One Plane It Needs To Bomb Iran."] {{webarchive|url=https://web.archive.org/web/20121212050635/http://articles.businessinsider.com/2012-03-28/news/31247799_1_b-2s-whiteman-air-force-base-stealth-bombers |date=12 December 2012}} ''Business Insider'', 28 March 2012.</ref> Continued modernization efforts likely have continued in secret, as alluded to by a B-2 commander from [[Whiteman Air Force Base]] in April 2021, possibly indicating offensive weapons capability against threatening air defenses and aircraft. He stated: {{blockquote |text=without getting into specifics, and without getting into things that we frankly just don't discuss in open channels, I will tell you that our current bomber fleet, and this is all of them, we use some pretty innovative ways to integrate modern weapons capabilities to have us both maintain and increase our survivability. And for the B-2 specifically, the expansion of some of our strike capabilities allow us to increase our survivability beyond the fighter escort realm. Now the B-2 fleet is continuing to do that technological advancement, and that's enabled us to expand our strike capabilities, as well. Although we've been around for over 30 years there's a lot of life left in this platform and up until the B-21 as well on the scene and doing its job, this aircraft will continue to be at the forefront of our country and our nation's defense... and with these, and continued innovative upgrades, and weapons system capabilities we will continue to do that until the last jet flies off the ramp into retirement.<ref>Mitchell Institute Aerospace Advantage Podcast [https://mitchellaerospacepower.org/episode-18-flying-and-fighting-in-the-b-2-americas-stealth-bomber/ "Flying and Fighting in the B-2: America’s Stealth Bomber"] {{Webarchive|url=https://web.archive.org/web/20210804180843/https://mitchellaerospacepower.org/episode-18-flying-and-fighting-in-the-b-2-americas-stealth-bomber/ |date=4 August 2021}} ''Mitchell Institute'', 11 April 2021. Retrieved 12 April 2021.</ref>}}

It was reported in 2011 that The Pentagon was evaluating an unmanned stealth bomber, characterized as a "mini-B-2", as a potential replacement in the near future.<ref>[http://www.uasvision.com/2011/05/24/pentagon-wants-unmanned-stealth-bomber-to-replace-b-2/ "Pentagon Wants Unmanned Stealth Bomber to Replace B-2."] {{Webarchive|url=https://web.archive.org/web/20120114162040/http://www.uasvision.com/2011/05/24/pentagon-wants-unmanned-stealth-bomber-to-replace-b-2/ |date=14 January 2012}} ''Los Angeles Times'' via ''uasvision.com'', 24 March 2011.</ref> In 2012, USAF Chief of Staff General [[Norton Schwartz]] stated the B-2's 1980s-era stealth technologies would make it less survivable in future contested airspaces, so the USAF is to proceed with the [[Next-Generation Bomber]] despite overall budget cuts.<ref>Schogol, Jeff. [https://archive.today/20130121151525/http://www.defensenews.com/article/20120229/DEFREG02/302290005/Schwartz-Defends-Cost-USAF-8217-s-Next-Gen-Bomber?odyssey=tab |topnews|text|FRONTPAGE "Schwartz Defends Cost of USAF's Next-Gen Bomber"] . ''Defense News''. 29 February 2012.</ref> In 2012 projections, it was estimated that the Next-Generation Bomber would have an overall cost of $55&nbsp;billion.<ref>Less, Eloise. [http://www.businessinsider.com/next-generation-b2-bomber-2012-3 "Questions about whether the US needs another $55 billion worth of bombers."] {{Webarchive|url=https://web.archive.org/web/20121212053548/http://www.businessinsider.com/next-generation-b2-bomber-2012-3 |date=12 December 2012}} ''Business Insider'', 27 March 2012.</ref>

In 2013, the USAF contracted for the Defensive Management System Modernization (DMS-M) program to replace the antenna system and other electronics to increase the B-2's frequency awareness.<ref>{{cite web|url=http://www.afgsc.af.mil/news/story.asp?id=123356798|title=Bolstering Spirits in the Year of the B-2|work=af.mil|url-status=dead|archive-url=https://web.archive.org/web/20131101052224/http://www.afgsc.af.mil/news/story.asp?id=123356798|archive-date=1 November 2013}}</ref> The Common Very Low Frequency Receiver upgrade allows the B-2s to use the same [[very low frequency]] transmissions as the [[Ohio-class submarine|''Ohio''-class submarine]]s so as to continue in the nuclear mission until the [[Mobile User Objective System]] is fielded.{{citation needed|date=December 2022}} In 2014, the USAF outlined a series of upgrades including nuclear warfighting, a new integrated processing unit, the ability to carry cruise missiles, and threat warning improvements.<ref>{{cite news |url=http://www.dodbuzz.com/2014/06/25/b-2-bomber-set-to-receive-massive-upgrade/ |title=B-2 Bomber Set to Receive Massive Upgrade |last1=Osborn |first1=Kris |date=25 June 2014 |website=dodbuzz.com |publisher=Monster |access-date=25 June 2014 |archive-url=https://web.archive.org/web/20170223212937/https://www.dodbuzz.com/2014/06/25/b-2-bomber-set-to-receive-massive-upgrade/ |archive-date=23 February 2017 |url-status=dead}}</ref> Due to ongoing software challenges, DMS-M was canceled by 2020, and the existing work was repurposed for cockpit upgrades.<ref>{{cite web |last=Wolfe |first=Frank |url=https://www.defensedaily.com/air-force-looks-increase-b-2-mission-readiness-cockpit-display-upgrade/air-force/ |title= Air Force Looks to Increase B-2 Mission Readiness with Cockpit Display Upgrade |work=Defense Industry Daily |date=23 October 2020}}</ref>

In 1998, a Congressional panel advised the USAF to refocus resources away from continued B-2 production and instead begin development of a new bomber, either a new build or a variant of the B-2. In its 1999 bomber roadmap the USAF eschewed the panel's recommendations, believing its current bomber fleet could be maintained until the 2030s. The service believed that development could begin in 2013, in time to replace aging B-2s, B-1s and B-52s around 2037.<ref>Tirpak, John A. [http://www.airforcemag.com/MagazineArchive/Pages/1999/June%201999/0699bomber.aspx "The Bomber Roadmap"] {{Webarchive|url=https://web.archive.org/web/20160229023812/http://www.airforcemag.com/MagazineArchive/Pages/1999/June%201999/0699bomber.aspx |date=29 February 2016}}. Air Force Magazine, June 1999. Retrieved 30 December 2015 ([http://www.airforcemag.com/MagazineArchive/Documents/1999/June%201999/0699bomber.pdf PDF version] {{Webarchive|url=https://web.archive.org/web/20160304141259/http://www.airforcemag.com/MagazineArchive/Documents/1999/June%201999/0699bomber.pdf |date=4 March 2016}})</ref><ref>Grant, Rebecca. [https://web.archive.org/web/20141103010442/http://www.dtic.mil/get-tr-doc/pdf?AD=ADA465958 "Return of the Bomber, The Future of Long-Range Strike"], pp. 11, 17, 29. Air Force Association, February 2007.</ref>

Although the USAF previously planned to operate the B-2 until 2058, the FY 2019 budget moved up its retirement to "no later than 2032". It also moved the retirement of the B-1 to 2036 while extending the B-52's service life into the 2050s, because the B-52 has lower maintenance costs, versatile conventional payload, and the ability to carry nuclear [[cruise missile]]s (which the B-1 is treaty-prohibited from doing). The decision to retire the B-2 early was made because the small fleet of 20 is considered too expensive per plane to retain, with its position as a stealth bomber being taken over with the introduction of the [[Northrop Grumman B-21 Raider|B-21 Raider]] starting in the mid-2020s.<ref name="airforcetimes11feb18"/>

==Design==
[[File:US Air Force B-2 Spirit.jpg|thumb|left|Side view of a B-2 Spirit]]

===Overview===
The B-2 Spirit was developed to take over the USAF's vital penetration missions, allowing it to travel deep into enemy territory to deploy [[aircraft ordnance|ordnance]], which could include [[nuclear weapon]]s.<ref name= "croddy 341-2">Croddy and Wirtz 2005, pp. 341–342.</ref> The B-2 is a [[flying wing]] aircraft, meaning that it has no fuselage or tail.<ref name= "croddy 341-2"/> It has significant advantages over previous bombers due to its blend of low-observable technologies with high aerodynamic efficiency and a large payload. Low observability provides greater freedom of action at high altitudes, thus increasing both range and field of view for onboard sensors. The USAF reports its range as approximately {{convert|6000|nmi|mi km|lk=in}}.<ref name=B-2_AF_fact_sheet/><ref name=Spick_p340-1>{{harvnb|Spick|2000|pp= 340–341}}</ref> At cruising altitude, the B-2 [[aerial refueling|refuels]] every six hours, taking on up to {{convert|50|ST|kg}} of fuel at a time.<ref name="chiles201309" />

The development and construction of the B-2 required pioneering use of [[computer-aided design]] and [[computer-aided manufacturing|manufacturing]] technologies due to its complex flight characteristics and design requirements to maintain very low visibility to multiple means of detection.<ref name= "croddy 341-2"/><ref>{{harvnb|Sweetman|2005|pp=73–74}}</ref> The B-2 bears a resemblance to earlier Northrop aircraft; the [[Northrop YB-35|YB-35]] and [[Northrop YB-49|YB-49]] were both flying wing bombers that had been canceled in development in the early 1950s,<ref name= "boyne 466">{{harvnb|Boyne|2002|p=466}}</ref> allegedly for political reasons.<ref>{{harvnb|Fitzsimons|1978|p=2282}}</ref> The resemblance goes as far as B-2 and YB-49 having the same wingspan.<ref>Noland, David. "[http://www.infoplease.com/spot/northropb2.html Bombers: Northrop B-2] {{Webarchive|url=https://web.archive.org/web/20140425004938/http://www.infoplease.com/spot/northropb2.html |date=25 April 2014}}" ''Infoplease'', 2007. Retrieved 24 April 2014.</ref><ref>"[http://www.military-heat.com/42/b2-spirit-stealth-bomber/ The B-2 Spirit stealth bomber] {{Webarchive|url=https://web.archive.org/web/20140425004903/http://www.military-heat.com/42/b2-spirit-stealth-bomber/ |date=25 April 2014}}" ''Military Heat'', 2007. Retrieved 24 April 2014.</ref> The YB-49 also had a small [[radar cross-section]].<ref>{{Cite web|url=https://fas.org/nuke/guide/usa/bomber/b-49.htm|title=B-49 – United States Nuclear Forces|access-date=29 July 2018|archive-date=26 March 2019|archive-url=https://web.archive.org/web/20190326095032/https://fas.org/nuke/guide/usa/bomber/b-49.htm|url-status=live}}</ref><ref>{{Cite magazine |last=Heppenheimer |first=T. A. |date=September 1986 |title=Stalth – First glimpses of the invisible aircraft now under construction |url=https://books.google.com/books?id=NUzwukoJzGIC&q=YB-49+radar&pg=PA76 |magazine=Popular Science |page=76 |access-date=27 October 2020 |archive-date=5 February 2021 |archive-url=https://web.archive.org/web/20210205101204/https://books.google.com/books?id=NUzwukoJzGIC&q=YB-49+radar&pg=PA76 |url-status=live}}</ref>

Approximately 80 pilots fly the B-2.<ref name="chiles201309" /> Each aircraft has a crew of two, a pilot in the left seat and mission commander in the right,<ref name=B-2_AF_fact_sheet/> and has provisions for a third crew member if needed.<ref>{{cite web|title=B-2 Spirit Stealth Bomber Facts|url=http://www.northropgrumman.com/Capabilities/B2SpiritBomber/Documents/pageDocuments/B2-Fact-Sheet.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.northropgrumman.com/Capabilities/B2SpiritBomber/Documents/pageDocuments/B2-Fact-Sheet.pdf |archive-date=9 October 2022 |url-status=live|publisher=[[Northrop Grumman]]|date=14 March 2007|access-date=15 June 2016}}</ref> For comparison, the B-1B has a crew of four and the B-52 has a crew of five.<ref name=B-2_AF_fact_sheet/> The B-2 is highly automated, and one crew member can sleep in a [[camp bed]], use a toilet, or prepare a hot meal while the other monitors the aircraft, unlike most two-seat aircraft. Extensive [[sleep cycle]] and [[fatigue (safety)|fatigue]] research was conducted to improve crew performance on long sorties.<ref name="chiles201309" /><ref name="tirpak199604">{{cite journal |url=http://www.airforcemag.com/MagazineArchive/Pages/1996/April%201996/0496bomber.aspx |archive-url=https://web.archive.org/web/20131112190523/http://www.airforcemag.com/MagazineArchive/Pages/1996/April%201996/0496bomber.aspx |archive-date=12 November 2013 |title=With the First B-2 Squadron |author=Tirpak, John A. |journal=Air Force Magazine |date=April 1996 |volume=79 |issue=4}}</ref><ref>Kenagy, David N., Christopher T. Bird, Christopher M. Webber and Joseph R. Fischer. [http://www.ingentaconnect.com/content/asma/asem/2004/00000075/00000005/art00001 "Dextroamphetamine Use During B-2 Combat Mission."] {{Webarchive|url=https://web.archive.org/web/20131112181039/http://www.ingentaconnect.com/content/asma/asem/2004/00000075/00000005/art00001 |date=12 November 2013}} ''Aviation, Space, and Environmental Medicine'', Volume 75, Number 5, May 2004, pp. 381–386.</ref> Advanced training is conducted at the [[USAF Weapons School]].<ref name="isis">{{cite magazine |magazine=[[The Atlantic]] |title=An Extraordinarily Expensive Way to Fight ISIS |archive-url=https://web.archive.org/web/20180627111647/https://www.theatlantic.com/magazine/archive/2018/07/william-langewiesche-b-2-stealth-bomber/561719/ |archive-date=27 June 2018 |url=https://www.theatlantic.com/magazine/archive/2018/07/william-langewiesche-b-2-stealth-bomber/561719/ |first=William |last=Langewiesche |date=July 2018}}</ref>

===Armaments and equipment===
[[File:B-2 bomb bay 050411-F-1740G-005.jpg|thumb|right|A {{convert|2000|lb|kg|abbr=on}} BDU-56 bomb being loaded onto a bomb bay's rotary launcher, 2004]]

In the envisaged Cold War scenario, the B-2 was to perform deep-penetrating nuclear strike missions, making use of its stealthy capabilities to avoid detection and interception throughout the missions.<ref name="tucker 39">{{harvnb|Tucker|2010|p=39}}</ref> There are two internal bomb bays in which munitions are stored either on a rotary launcher or two bomb-racks; the carriage of the weapons loadouts internally results in less radar visibility than external mounting of munitions.<ref>{{harvnb|Moir|Seabridge|2008|p=398}}</ref><ref name="tucker 177" /> The B-2 is capable of carrying {{convert|40000|lb|kg|abbr=on}} of ordnance.<ref name=B-2_AF_fact_sheet/> Nuclear ordnance includes the [[B61 nuclear bomb|B61]] and [[B83 nuclear bomb]]s; the [[AGM-129 ACM]] cruise missile was also intended for use on the B-2 platform.<ref name="tucker 177" /><ref>{{harvnb|Richardson|2001|pp=120–121}}</ref>

In light of the dissolution of the Soviet Union, it was decided to equip the B-2 for conventional precision attacks as well as for the strategic role of nuclear-strike.<ref name="tucker 39" /><ref>{{harvnb|Rip|Hasik|2002|p=201}}</ref> The B-2 features a sophisticated GPS-Aided Targeting System (GATS) that uses the aircraft's [[APQ-181 radar|APQ-181]] [[synthetic aperture radar]] to map out targets prior to the deployment of [[Global Positioning System|GPS]]-aided bombs ([[GBU-37|GAMs]]), later superseded by the [[Joint Direct Attack Munition]] (JDAM). In the B-2's original configuration, up to 16 GAMs or JDAMs could be deployed;<ref>{{harvnb|Rip|Hasik|2002|pp=242–246}}</ref> An upgrade program in 2004 raised the maximum carrier capacity to 80 JDAMs.<ref name=POGO />

The B-2 has various conventional weapons in its arsenal, including [[Mark 82 bomb|Mark 82]] and [[Mark 84 bomb]]s, [[CBU-87 Combined Effects Munition]]s, [[GATOR mine system|GATOR mine]]s, and the [[CBU-97 Sensor Fuzed Weapon]].<ref>{{harvnb|Evans|2004|p=13}}</ref> In July 2009, Northrop Grumman reported the B-2 was compatible with the equipment necessary to deploy the {{convert|30000|lb|kg|abbr=on|adj=on}} [[Massive Ordnance Penetrator]] (MOP), which is intended to attack reinforced [[bunker]]s; up to two MOPs could be equipped in the B-2's bomb bays with one per bay,<ref>Mayer, Daryl. [http://www.defpro.com/news/details/8738/ "Northrop Grumman and USAF Verify Proper Fit of 30,000 lb Penetrator Weapon on B-2 Bomber."] {{webarchive|url=https://web.archive.org/web/20090821060646/http://www.defpro.com/news/details/8738/ |date=21 August 2009}} defpro.com, 22 July 2009. Retrieved 13 September 2009.</ref> the B-2 is the only platform compatible with the MOP as of 2012.<ref name="kelley insider" /> As of 2011, the [[AGM-158 JASSM]] [[cruise missile]] is an upcoming standoff munition to be deployed on the B-2 and other platforms.<ref>[http://www.defenseindustrydaily.com/AGM-158-JASSM-Cruise-Missiles-FY-2011-Orders-06895/ "AGM-158 JASSM Cruise Missiles: FY 2011 Orders."] {{Webarchive|url=https://web.archive.org/web/20120602080654/http://www.defenseindustrydaily.com/AGM-158-JASSM-Cruise-Missiles-FY-2011-Orders-06895/ |date=2 June 2012}} ''Defense Industry Daily'', 14 May 2011.</ref> This is to be followed by the [[Long Range Standoff Weapon]], which may give the B-2 standoff nuclear capability for the first time.<ref>{{cite web |url=http://blogs.fas.org/security/2013/04/b-2bomber/ |title=B-2 Stealth Bomber To Carry New Nuclear Cruise Missile |last1=Kristensen |first1=Hans M. |date=22 April 2013 |work=FAS Strategic Security Blog |publisher=Federation of American Scientists |access-date=22 April 2013 |url-status=dead |archive-url=https://web.archive.org/web/20140422075113/http://blogs.fas.org/security/2013/04/b-2bomber/ |archive-date=22 April 2014}}</ref>

===Avionics and systems===
To make the B-2 more effective than previous bombers, many advanced and modern avionics systems were integrated into its design; these have been modified and improved following a switch to conventional warfare missions. One system is the [[low probability of intercept]] [[AN/APQ-181]] multi-mode radar, a fully digital navigation system that is integrated with [[terrain-following radar]] and [[Global Positioning System]] (GPS) guidance, NAS-26 [[astro-inertial navigation system]] (first such system tested on the Northrop [[SM-62 Snark]] cruise missile)<ref>{{cite book|last=Sweetman|first=Bill|title=Inside the Stealth Bomber|year=1999|url=https://books.google.com/books?id=Q_wyJ_pKcqoC&pg=PA55|publisher=Zenith Imprint|page=57|isbn=978-1-61060-689-9|access-date=19 October 2016|archive-date=15 February 2020|archive-url=https://web.archive.org/web/20200215143146/https://books.google.com/books?id=Q_wyJ_pKcqoC&pg=PA55|url-status=live}}</ref> and a Defensive Management System (DMS) to inform the flight crew of possible threats.<ref name= POGO/> The onboard DMS is capable of automatically assessing the detection capabilities of identified threats and indicated targets.<ref name= "sweetman 73">{{harvnb|Sweetman|2005|p=73}}</ref> The DMS will be upgraded by 2021 to detect radar emissions from air defenses to allow changes to the auto-router's mission planning information while in-flight so it can receive new data quickly to plan a route that minimizes exposure to dangers.<ref name="military24april15">[http://www.military.com/daily-news/2015/04/24/air-force-upgrades-b2-stealth-bomber-as-air-defenses-advance.html?ESRC=todayinmil.sm Air Force Upgrades B-2 Stealth Bomber as Modern Air Defenses Advance] {{Webarchive|url=https://web.archive.org/web/20161126200312/http://www.military.com/daily-news/2015/04/24/air-force-upgrades-b2-stealth-bomber-as-air-defenses-advance.html?ESRC=todayinmil.sm |date=26 November 2016}} – Military.com, 24 April 2015</ref>

[[File:B-2 Spirit 050413-F-1740G-001a.jpg|thumb|upright=1.35|left|A maintenance crew servicing a B-2 at [[Andersen Air Force Base|Andersen AFB]], [[Guam]], 2004]]
For safety and fault-detection purposes, an on-board test system is linked with the majority of avionics on the B-2 to continuously monitor the performance and status of thousands of components and consumables; it also provides post-mission servicing instructions for ground crews.<ref>{{harvnb|Siuru|1993|p=118}}</ref> In 2008, many of the 136<ref>{{cite book|title=Air Warfare|url=https://books.google.com/books?id=FW_50wm8VnMC&pg=PA466|publisher=ABC-CLIO|isbn=978-1-57607-345-2|page=466|year=2002|access-date=19 October 2016|archive-date=5 February 2021|archive-url=https://web.archive.org/web/20210205101206/https://books.google.com/books?id=FW_50wm8VnMC&pg=PA466|url-status=live}}</ref> standalone distributed computers on board the B-2, including the primary flight management computer, were being replaced by a single integrated system.<ref>Page, Lewis. [https://www.theregister.co.uk/2008/07/11/stealth_bomber_upgrades/ "Upgrade drags Stealth Bomber IT systems into the 90s."] {{Webarchive|url=https://web.archive.org/web/20170810141519/https://www.theregister.co.uk/2008/07/11/stealth_bomber_upgrades/ |date=10 August 2017}} ''The Register'', 11 July 2008.</ref> The avionics are controlled by 13 [[Electromagnetic pulse|EMP]]-resistant [[MIL-STD-1750A]] computers, which are interconnected through 26 [[MIL-STD-1553]]B-[[bus (computing)|busses]]; other system elements are connected via [[optical fiber]].<ref name="janes" />

In addition to periodic software upgrades and the introduction of new radar-absorbent materials across the fleet, the B-2 has had several major upgrades to its avionics and combat systems. For battlefield communications, both [[Link-16]] and a high frequency satellite link have been installed, compatibility with various new munitions has been undertaken, and the AN/APQ-181 radar's operational frequency was shifted to avoid interference with other operators' equipment.<ref name= POGO/> The arrays of the upgraded radar features were entirely replaced to make the AN/APQ-181 into an [[active electronically scanned array]] (AESA) radar.<ref>[http://www.raytheon.com/capabilities/products/apq181/ "AN/APQ-181 Radar System."] {{webarchive|url=https://web.archive.org/web/20120824004350/http://www.raytheon.com/capabilities/products/apq181/ |date=24 August 2012}} ''Raytheon''. Retrieved 11 August 2012.</ref> Due to the B-2's composite structure, it is required to stay {{convert|40|mi|km|abbr=out|sigfig=|sp=us}} away from [[thunderstorms]], to avoid [[static discharge]] and [[lightning strike]]s.<ref name="isis"/>

===Flight controls===
[[File:Vice President Dick Cheney talking inside cockpit at a rally for the B-2 Bomber Forces.jpg|thumb|Vice President [[Dick Cheney]] inside a B-2 cockpit with pilot Capt. Luke Jayne during a visit to [[Whiteman AFB]], 2006]]

To address the inherent flight instability of a [[flying wing]] aircraft, the B-2 uses a complex quadruplex computer-controlled [[fly-by-wire]] flight control system that can automatically manipulate flight surfaces and settings without direct pilot inputs to maintain aircraft stability.<ref>{{harvnb|Moir|Seabridge|2008|p=397}}</ref> The flight computer receives information on external conditions such as the aircraft's current air speed and angle of attack via [[pitot tube|pitot]]-static sensing plates, as opposed to traditional [[pitot tube]]s which would impair the aircraft's stealth capabilities.<ref>{{harvnb|Moir|Seabridge|2008|pp=256–258}}</ref> The flight actuation system incorporates both hydraulic and electrical servoactuated components, and it was designed with a high level of redundancy and fault-diagnostic capabilities.<ref>[http://www.moog.com/markets/aircraft/military-aircraft/special-mission/flight-control-actuation-system-integrator-for-the-b-2-spirit/ "Flight Control Actuation System Integrator for the B-2 Spirit."] {{Webarchive|url=https://web.archive.org/web/20120922075806/http://www.moog.com/markets/aircraft/military-aircraft/special-mission/flight-control-actuation-system-integrator-for-the-b-2-spirit/ |date=22 September 2012}} ''Moog''. Retrieved 11 August 2012.</ref>

Northrop had investigated several means of applying directional control that would infringe on the aircraft's radar profile as little as possible, eventually settling on a combination of split brake-rudders and differential thrust.<ref name= "sweetman 73"/> Engine thrust became a key element of the B-2's aerodynamic design process early on; thrust not only affects drag and lift but pitching and rolling motions as well.<ref>{{harvnb|Chudoba|2001|p=76}}</ref> Four pairs of control surfaces are located along the wing's trailing edge; while most surfaces are used throughout the aircraft's flight envelope, the inner elevons are normally only in use at slow speeds, such as landing.<ref name= "chudoba 201-2">{{harvnb|Chudoba|2001|pp=201–202}}</ref> To avoid potential contact damage during takeoff and to provide a nose-down pitching attitude, all of the elevons remain drooped during takeoff until a high enough airspeed has been attained.<ref name= "chudoba 201-2"/>

===Stealth===
[[File:B2 Spirit closeup.JPEG|thumb|The B-2's engines are buried within its wing to conceal the engines' fans and minimize their exhaust signature.]]

The B-2's low-observable, or "[[stealth technology|stealth]]", characteristics enable the undetected penetration of sophisticated anti-aircraft defenses and to attack even heavily defended targets. This stealth comes from a combination of reduced [[Acoustic signature|acoustic]], [[Infrared signature|infrared]], [[Aircraft camouflage|visual]] and [[Radar cross-section|radar signature]]s ([[multi-spectral camouflage]]) to evade the various detection systems that could be used to detect and be used to direct attacks against an aircraft. The B-2's stealth enables the reduction of supporting aircraft that are required to provide air cover, [[Suppression of Enemy Air Defenses]] and [[electronic countermeasure]]s, making the bomber a "[[force multiplier]]". {{As of|2013|09}}, there have been no instances of a missile being launched at a B-2.<ref name="chiles201309" />

To reduce optical visibility during daylight flights, the B-2 is painted in an [[aircraft camouflage|anti-reflective paint]].<ref name= "tucker 177">{{harvnb|Tucker|2010|p=177}}</ref> The undersides are dark because it flies at high altitudes ({{convert|50000|ft|m|abbr=on|disp=}}), and at that altitude a dark grey painting blends well into the sky. It is speculated to have an upward-facing [[Photodetector|light sensor]] which alerts the pilot to increase or reduce altitude to match the changing illuminance of the sky.<ref>{{cite book|last=Sweetman|first=Bill|title=Inside the Stealth Bomber|year=1999|url=https://books.google.com/books?id=Q_wyJ_pKcqoC&pg=PA55|publisher=Zenith Imprint|page=55|isbn=978-1-61060-689-9|access-date=19 October 2016|archive-date=15 February 2020|archive-url=https://web.archive.org/web/20200215143146/https://books.google.com/books?id=Q_wyJ_pKcqoC&pg=PA55|url-status=live}}</ref> The original design had tanks for a [[contrail]]-inhibiting chemical, but this was replaced in production aircraft by a contrail sensor that alerts the crew when they should change altitude.<ref>Gosnell, Mariana. [http://www.airspacemag.com/flight-today/Flight_Lines.html "Why contrails hang around."] {{Webarchive|url=https://web.archive.org/web/20131112175852/http://www.airspacemag.com/flight-today/Flight_Lines.html |date=12 November 2013}} ''Air & Space magazine'', 1 July 2007. Retrieved 13 September 2009.</ref> The B-2 is vulnerable to visual interception at ranges of {{convert|20|nmi|mi km|abbr=on}} or less.<ref name="chiles201309" /> The B-2 is stored in a $5&nbsp;million specialised air-conditioned hangar to maintain its stealth coating. Every seven years, this coating is carefully washed away with crystallised wheat starch so that the B-2's surfaces can be inspected for any dents or scratches.<ref>{{Cite web|url=https://nationalinterest.org/blog/buzz/why-air-force-only-has-20-b-2-spirit-stealth-bombers-35802|title=Why the Air Force Only Has 20 B-2 Spirit Stealth Bombers|author=Sebastien Roblin|date=11 November 2018|website=National Interest|access-date=5 November 2020|archive-date=18 September 2020|archive-url=https://web.archive.org/web/20200918112631/https://nationalinterest.org/blog/buzz/why-air-force-only-has-20-b-2-spirit-stealth-bombers-35802|url-status=live}}</ref>

====Radar====
The B-2's clean, low-drag [[flying wing]] configuration not only provides exceptional range but is also beneficial to reducing its radar profile.<ref name="croddy 341-2" /><ref>{{harvnb|Siuru|1993|pages=114–115}}</ref> Reportedly, the B-2 has a [[radar cross-section]] (RCS) of about {{convert|0.1|m2|ft2|abbr=on}}.<ref>{{harvnb|Richardson|2001|p=57}}</ref> The bomber does not always fly stealthily; when nearing air defenses pilots "stealth up" the B-2, a maneuver whose details are secret. The aircraft is stealthy, except briefly when the bomb bay opens.  The flying wing design most closely resembles a so-called infinite flat plate (as vertical control surfaces dramatically increase RCS), the perfect stealth shape, as it would lack angles to reflect back radar waves (initially, the shape of the Northrop ATB concept was flatter; it gradually increased in volume according to specific military requirements).<ref name="SpiritofInnovation">{{cite web |url=https://www.northropgrumman.com/wp-content/uploads/B-2-Spirit-of-Innovation.pdf |title=B-2: The Spirit of Innovation |website=Northrop Grumman Corporation |access-date=15 October 2023 |archive-date=8 April 2023 |archive-url=https://web.archive.org/web/20230408033411/https://www.northropgrumman.com/wp-content/uploads/B-2-Spirit-of-Innovation.pdf |url-status=live}}</ref> Without vertical surfaces to reflect radar laterally, side aspect radar cross section is also reduced.<ref>{{cite web|url=https://nationalinterest.org/blog/buzz/americas-new-b-21-stealth-bomber-vs-russias-s-300-or-s-400-who-wins-36137|title=America's New B-21 Stealth Bomber vs. Russia's S-300 or S-400: Who Wins?|first=Kris|last=Osborn|date=15 November 2018|website=nationalinterest.org|access-date=16 November 2018|archive-date=15 November 2018|archive-url=https://web.archive.org/web/20181115195225/https://nationalinterest.org/blog/buzz/americas-new-b-21-stealth-bomber-vs-russias-s-300-or-s-400-who-wins-36137|url-status=live}}</ref> Radars operating at a lower frequency band (S or L band) are able to detect and track certain stealth aircraft that have multiple control surfaces, like canards or vertical stabilizers, where the frequency wavelength can exceed a certain threshold and cause a resonant effect.<ref>{{cite web|url=https://nationalinterest.org/blog/buzz/how-russia-could-someday-shootdown-f-22-f-35-or-b-2-stealth-bomber-35512|title=How Russia Could Someday Shootdown an F-22, F-35 or B-2 Stealth Bomber|first=Dave|last=Majumdar|date=8 November 2018|website=nationalinterest.org|access-date=21 November 2018|archive-date=20 November 2018|archive-url=https://web.archive.org/web/20181120221212/https://nationalinterest.org/blog/buzz/how-russia-could-someday-shootdown-f-22-f-35-or-b-2-stealth-bomber-35512|url-status=live}}</ref>

[[File:B-2 radar reflection.jpg|thumb|left|upright=1.35|Illustration of the B-2's basic radar reflection angles]]
RCS reduction as a result of shape had already been observed on the [[Royal Air Force]]'s [[Avro Vulcan]] strategic bomber,<ref>Dawson 1957, p. 3.</ref> and the USAF's [[Lockheed F-117 Nighthawk|F-117 Nighthawk]]. The F-117 used flat surfaces ([[faceting]] technique) for controlling radar returns as during its development (see [[Lockheed Have Blue]]) in the early 1970s, technology only allowed for the simulation of radar reflections on simple, flat surfaces; computing advances in the 1980s made it possible to simulate radar returns on more complex curved surfaces.<ref name="rich4">{{harvnb|Rich|1994|p=21}}</ref> The B-2 is composed of many curved and rounded surfaces across its exposed airframe to deflect radar beams. This technique, known as ''continuous curvature'', was made possible by advances in [[computational fluid dynamics]], and first tested on the [[Northrop Tacit Blue]].<ref>{{cite book|author=Christopher Lavers|title=Reeds Vol 14: Stealth Warship Technology|url=https://books.google.com/books?id=wMB3Pg3vtbsC&pg=PA13|year=2012|publisher=Bloomsbury Publishing|isbn=978-1-4081-7553-8|page=13|access-date=19 October 2016|archive-date=5 February 2021|archive-url=https://web.archive.org/web/20210205102939/https://books.google.com/books?id=wMB3Pg3vtbsC&pg=PA13|url-status=live}}</ref><ref name="SpiritofInnovation"/>

====Infrared====
[[File:B-2 inlet.jpg|thumb|The gap below the air intake has the purpose of keeping the [[boundary layer]] out of the jet engine.]]

Some analysts claim [[infra-red search and track]] systems (IRSTs) can be deployed against stealth aircraft, because any aircraft surface heats up due to air friction and with a two channel IRST is a {{CO2}} (4.3&nbsp;μm absorption maxima) detection possible, through difference comparing between the low and high channel.<ref>{{cite web |last=Radar |first=Cordless |url=http://www.flightglobal.com/blogs/the-dewline/2008/10/infamous-jsf-report-precedes-a.html |title=RAND Report Page 37 |work=Flight International |access-date=16 December 2010 |archive-date=10 May 2013 |archive-url=https://web.archive.org/web/20130510192736/http://www.flightglobal.com/blogs/the-dewline/2008/10/infamous-jsf-report-precedes-a.html |url-status=live}}</ref><ref name="fas_stealth">{{Cite web |title=VI – STEALTH AIRCRAFT: EAGLES AMONG SPARROWS? |publisher=Federation of American Scientist |url=https://fas.org/spp/aircraft/part06.htm |access-date=21 February 2008 |journal= |archive-date=13 February 2008 |archive-url=https://web.archive.org/web/20080213001551/http://www.fas.org/spp/aircraft/part06.htm |url-status=dead}}</ref>

Burying engines deep inside the fuselage also minimizes the thermal visibility or [[infrared signature]] of the exhaust.<ref name= "tucker 177"/><ref>Croddy and Wirtz 2005, p. 342.</ref> At the engine intake, cold air from the [[boundary layer]] below the main inlet enters the fuselage ([[boundary layer suction]], first tested on the [[Northrop X-21]]) and is mixed with hot exhaust air just before the [[nozzle]]s (similar to the [[Ryan AQM-91 Firefly]]). According to the [[Stefan–Boltzmann law]], this results in less energy ([[thermal radiation]] in the infrared spectrum) being released and thus a reduced heat signature. The resulting cooler air is conducted over a surface composed of heat resistant [[carbon-fiber-reinforced polymer]] and [[titanium alloy]] elements, which disperse the air laterally, to accelerate its cooling.<ref name="janes">Jane's Aircraft Upgrades 2003, p. 1711f</ref> The B-2 lacks [[afterburner]]s as the hot exhaust would increase the infrared signature; breaking the [[sound barrier]] would produce an obvious [[sonic boom]] as well as [[aerodynamic heating]] of the [[aircraft skin]] which would also increase the infrared signature.

====Materials====
According to the [[Huygens–Fresnel principle]], even a very flat plate would still reflect radar waves, though much less than when a signal is bouncing at a right angle. Additional reduction in its radar signature was achieved by the use of various [[radar-absorbent material]]s (RAM) to absorb and neutralize radar beams. The majority of the B-2 is made out of a [[carbon]]-[[graphite]] [[composite material]] that is stronger than steel, lighter than aluminum, and absorbs a significant amount of radar energy.<ref name= "boyne 466"/>

The B-2 is assembled with unusually tight [[engineering tolerance]]s to avoid leaks as they could increase its radar signature.<ref name="tirpak199604" /> Innovations such as alternate [[high frequency]] material (AHFM) and automated material application methods were also incorporated to improve the aircraft's radar-absorbent properties and reduce maintenance requirements.<ref name= "tucker 177"/><ref>Lewis, Paul. [http://www.flightglobal.com/news/articles/b-2-to-receive-maintenance-boost-144086/ "B-2 to receive maintenance boost."] {{Webarchive |url=https://web.archive.org/web/20130516141406/http://www.flightglobal.com/news/articles/b-2-to-receive-maintenance-boost-144086/ |date=16 May 2013}} ''Flight International'', 5 March 2002.</ref> In early 2004, Northrop Grumman began applying a newly developed AHFM to operational B-2s.<ref>Hart, Jim. [http://www.irconnect.com/noc/press/pages/news_releases.html?d=56001 "Northrop Grumman Applies New Coating to Operational B-2."] {{Webarchive |url=https://web.archive.org/web/20111209000416/http://www.irconnect.com/noc/press/pages/news_releases.html?d=56001 |date=9 December 2011}} "Northrop Grumman Integrated Systems", 19 April 2004.</ref> To protect the operational integrity of its sophisticated radar absorbent material and coatings, each B-2 is kept inside a climate-controlled hangar (Extra Large Deployable Aircraft Hangar System) large enough to accommodate its {{convert|172|ft|m|adj=on}} wingspan.<ref name=AW_20070107_Away>Fulghum, D.A. [https://archive.today/20130117150011/http://www.aviationnow.com/search/AvnowSearchResult.do?reference=xml/awst_xml/2007/01/08/AW_01_08_2007_p50-51-01.xml "First F-22 large-scale, air combat exercise wins praise and triggers surprise" (online title), "Away Game".] ''[[Aviation Week & Space Technology]]'', 8 January 2007. Retrieved 13 September 2009.</ref>

====Shelter system====
B-2s are supported by portable, environmentally-controlled hangars called B-2 Shelter Systems (B2SS).<ref name="stripes">{{cite news |url=https://www.stripes.com/news/portable-b-2-bomber-shelters-are-built-in-parts-officially-unknown-1.1054 |title=Portable B-2 bomber shelters are built ... in parts (officially) unknown |newspaper=[[Stars and Stripes (newspaper)|Stars and Stripes]] |first=Wayne |last=Specht |date=16 January 2003 |access-date=24 June 2018 |archive-date=25 June 2018 |archive-url=https://web.archive.org/web/20180625022005/https://www.stripes.com/news/portable-b-2-bomber-shelters-are-built-in-parts-officially-unknown-1.1054 |url-status=live}}</ref> The hangars are built by American Spaceframe Fabricators Inc. and cost approximately US$5&nbsp;million apiece.<ref name="stripes"/> The need for specialized hangars arose in 1998 when it was found that B-2s passing through [[Andersen Air Force Base]] did not have the climate-controlled environment maintenance operations required.<ref name="stripes"/> In 2003, the B2SS program was managed by the Combat Support System Program Office at [[Eglin Air Force Base]].<ref name="stripes" /> B2SS hangars are known to have been deployed to [[Naval Support Facility Diego Garcia]] and [[RAF Fairford]].<ref name="stripes"/>

==Operational history==
[[File:B-2 Spirit 050404-F-1740G-001.jpg|thumb|A B-2 during [[aerial refueling]], which extends its range past {{convert|6000|nmi|mi km}} for intercontinental sorties]]

===1990s===
The first operational aircraft, christened ''Spirit of Missouri'', was delivered to [[Whiteman Air Force Base]], [[Missouri]], where the fleet is based, on 17 December 1993.<ref name=Pace_p66>{{harvnb|Pace|1999|p=66}}</ref> The B-2 reached initial operational capability (IOC) on 1 January 1997.<ref name=Pace_p73>{{harvnb|Pace|1999|p=73}}</ref> Depot maintenance for the B-2 is accomplished by USAF contractor support and managed at [[Oklahoma City Air Logistics Center]] at [[Tinker Air Force Base]].<ref name=B-2_AF_fact_sheet>[http://www.af.mil/AboutUs/FactSheets/Display/tabid/224/Article/104482/b-2-spirit.aspx "B-2 Spirit Fact Sheet."] {{Webarchive|url=https://web.archive.org/web/20170126095146/http://www.af.mil/AboutUs/FactSheets/Display/tabid/224/Article/104482/b-2-spirit.aspx |date=26 January 2017}} ''U.S. Air Force''. Retrieved 8 January 2015.</ref> Originally designed to deliver nuclear weapons, modern usage has shifted towards a flexible role with conventional and nuclear capability.<ref name= "tucker 177"/>

The B-2's combat debut was in 1999, during the [[Kosovo War]]. It was responsible for destroying 33% of selected Serbian bombing [[Bullseye (target)|targets]] in the first eight weeks of U.S. involvement in the war.<ref name=B-2_AF_fact_sheet/> During this war, six B-2s flew non-stop to [[Yugoslavia]] from their home base in Missouri and back, totaling 30 hours. Although the bombers accounted 50 sorties out of a total of 34,000 NATO sorties, they dropped 11 percent of all bombs.<ref>{{Cite news|last=Ho|first=David|url=http://www.highbeam.com/doc/1P1-23222353.html|archive-url=https://web.archive.org/web/20150924180425/http://www.highbeam.com/doc/1P1-23222353.html|url-status=dead|archive-date=24 September 2015|title=Air Force Says Bomber Performed Well|agency=Associated Press|date=30 June 1999|access-date=12 June 2015}}</ref> The B-2 was the first aircraft to deploy GPS satellite-guided [[Joint Direct Attack Munition|JDAM "smart bombs"]] in combat use in Kosovo.<ref>Hansen, Staff Sgt. Ryan. [https://web.archive.org/web/20060322232426/http://www.af.mil/news/story.asp?id=123017613 "JDAM continues to be warfighter's weapon of choice."] ''US Air Force'', 17 March 2006. Retrieved 13 September 2009.</ref> The use of JDAMs and precision-guided munitions effectively replaced the controversial tactic of [[Carpet bombing|carpet-bombing]], which had been harshly criticized due to it causing indiscriminate civilian casualties in prior conflicts, such as the 1991 [[Gulf War]].<ref>{{harvnb|Tucker|2010|pp= 177–178}}</ref> On 7 May 1999, a B-2 [[U.S. bombing of the Chinese embassy in Belgrade|dropped five JDAMs on the Chinese Embassy]], killing several staff.<ref>{{harvnb|Rip|Hasik|2002|p=398}}</ref> By then, the B-2 had dropped 500 bombs in Yugoslavia.<ref>{{Cite news|last=Diamond|first=John|url=http://www.highbeam.com/doc/1P1-23143398.html|archive-url=https://web.archive.org/web/20150924180409/http://www.highbeam.com/doc/1P1-23143398.html|url-status=dead|archive-date=24 September 2015|title=B-2s Turn Out Not To Be Solo Flyers|agency=Associated Press|date=7 May 1999|access-date=14 June 2015}}</ref>

===2000s===
The B-2 saw service in [[Afghanistan]], striking ground targets in support of [[War in Afghanistan (2001–2021)|Operation Enduring Freedom]]. With aerial refueling support, the B-2 flew one of its longest missions to date from Whiteman Air Force Base in Missouri to Afghanistan and back.<ref name=B-2_AF_fact_sheet/> B-2s would be stationed in the Middle East as a part of a US military buildup in the region from 2003.<ref>"Pressure mounts as stealth bombers deployed". ''The Age'', 28 February 2003.</ref>

The B-2's combat use preceded a USAF declaration of "full operational capability" in December 2003.<ref name=B-2_AF_fact_sheet/> The Pentagon's Operational Test and Evaluation 2003 Annual Report noted that the B-2's serviceability for Fiscal Year 2003 was still inadequate, mainly due to the maintainability of the B-2's low observable coatings. The evaluation also noted that the Defensive Avionics suite had shortcomings with "pop-up threats".<ref name=B-2_AF_fact_sheet/><ref name= "tucker 178">{{harvnb|Tucker|2010|p=178}}</ref>

During the [[Iraq War]], B-2s operated from [[Diego Garcia]] and an undisclosed "forward operating location". Other [[sortie]]s in Iraq have launched from Whiteman AFB.<ref name=B-2_AF_fact_sheet/> {{as of|2013|09}} the longest combat mission has been 44.3 hours.<ref name="chiles201309">{{cite news | url=http://www.airspacemag.com/military-aviation/The-Stealth-Bomber-Elite-220257381.html?c=y&story=fullstory | title=The Stealth Bomber Elite | work=Air & Space | date=September 2013 | access-date=9 September 2013 | author=Chiles, James R. | archive-date=12 November 2013 | archive-url=https://web.archive.org/web/20131112175855/http://www.airspacemag.com/military-aviation/The-Stealth-Bomber-Elite-220257381.html?c=y&story=fullstory | url-status=live}}</ref> "Forward operating locations" have been previously designated as [[Andersen Air Force Base]] in [[Guam]] and [[RAF Fairford]] in the United Kingdom, where new climate controlled hangars have been constructed. B-2s have conducted 27 sorties from Whiteman AFB and 22 sorties from a forward operating location, releasing more than {{convert|1500000|lb|kg}} of munitions,<ref name=B-2_AF_fact_sheet/> including 583 JDAM "smart bombs" in 2003.<ref name= POGO>[http://pogoarchives.org/m/dp/dp-2003-B2.pdf "Air Force programs: B-2."] {{Webarchive|url=https://web.archive.org/web/20110727182239/http://pogoarchives.org/m/dp/dp-2003-B2.pdf |date=27 July 2011}} ''Project On Government Oversight'' (POGO), 16 April 2004. Retrieved 13 September 2009.</ref>

===2010s===
[[File:B-2 Spirit Dyess AFB Air Show 2018.jpg|thumb|The ''Spirit of Missouri'' at the [[Dyess AFB]] air show in 2018. This view depicts the body's two dimensional and seamless design, a distinct feature for evading radar detection.]]

In response to organizational issues and high-profile mistakes made within the USAF,<ref>McNeil, Kirsten. [http://www.armscontrol.org/act/2008_12/nuclear_roadmap "Air Force Reorganizes Nuclear Commands."] {{Webarchive|url=https://web.archive.org/web/20120202203600/http://www.armscontrol.org/act/2008_12/nuclear_roadmap |date=2 February 2012}} ''armscontrol.org'', December 2012.</ref><ref>[http://news.bbc.co.uk/2/hi/americas/7690447.stm "US plans separate nuclear command."] {{Webarchive|url=https://web.archive.org/web/20081026020951/http://news.bbc.co.uk/2/hi/americas/7690447.stm |date=26 October 2008}} ''BBC News'', 25 October 2008. Retrieved 13 September 2009.</ref> all of the B-2s, along with the nuclear-capable B-52s and the USAF's [[intercontinental ballistic missile]]s (ICBMs), were transferred to the newly formed [[Air Force Global Strike Command]] on 1 February 2010.<ref>[https://web.archive.org/web/20100615133637/http://www.af.mil/news/story.asp?id=123188338 "Air Force Global Strike Command officials assume B-52, B-2 mission."] United States Air Force, 2 February 2010.</ref><ref>Chavanne, Bettina H. [http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=defense&id=news/GSC102408.xml&headline=USAF%20Creates%20Global%20Strike%20Command "USAF Creates Global Strike Command."] {{Webarchive|url=https://web.archive.org/web/20120111032006/http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=defense&id=news%2FGSC102408.xml&headline=USAF%20Creates%20Global%20Strike%20Command |date=11 January 2012}} ''Aviation Week'', 24 October 2008. Retrieved 13 September 2009.</ref>

In March 2011, B-2s were the first U.S. aircraft into action in [[Operation Odyssey Dawn]], the UN mandated enforcement of the [[Libyan no-fly zone]]. Three B-2s dropped 40 bombs on a Libyan airfield in support of the UN no-fly zone.<ref name="Crisis">Martin, David. [https://www.cbsnews.com/news/crisis-in-libya-us-bombs-qaddafis-airfields/ "Crisis in Libya: U.S. bombs Qaddafi's airfields."]  CBS News, 20 March 2011.</ref> The B-2s flew directly from the U.S. mainland across the Atlantic Ocean to Libya; a B-2 was refueled by allied tanker aircraft four times during each round trip mission.<ref>Tirpak, John A. [http://www.airforce-magazine.com/MagazineArchive/Pages/2011/July%202011/0711libya.aspx "Bombers Over Libya."] {{Webarchive|url=https://web.archive.org/web/20120730193442/http://www.airforce-magazine.com/MagazineArchive/Pages/2011/July%202011/0711libya.aspx |date=30 July 2012}} ''Air Force Magazine'', July 2011.</ref><ref>Marcus, Jonathan. [https://www.bbc.co.uk/news/world-africa-12813168 "Libya military operation: Who should command?"] {{Webarchive|url=https://web.archive.org/web/20180929215912/https://www.bbc.co.uk/news/world-africa-12813168 |date=29 September 2018}} ''BBC News'', 21 March 2011.</ref>

In August 2011, ''[[The New Yorker]]'' reported that prior to the May 2011 U.S. Special Operations raid into [[Abbottabad]], [[Pakistan]] that resulted in the [[death of Osama bin Laden]], U.S. officials had considered an airstrike by one or more B-2s as an alternative; the use of a [[bunker buster|bunker busting]] bomb was rejected due to potential damage to nearby civilian buildings.<ref>Schmidle, Nicholas. [http://www.newyorker.com/reporting/2011/08/08/110808fa_fact_schmidle?currentPage=all "Getting Bin Laden."] {{Webarchive|url=https://web.archive.org/web/20150513115000/http://www.newyorker.com/reporting/2011/08/08/110808fa_fact_schmidle?currentPage=all |date=13 May 2015}} ''The New Yorker'', 8 August 2011.</ref> There were also concerns an airstrike would make it difficult to positively identify Bin Laden's remains, making it hard to confirm his death.<ref>{{cite web |url=http://indiatoday.intoday.in/story/us-had-planned-air-strike-to-level-osama-abbottabad-hideout/1/216617.html |title=US had planned air strike to level Osama's Abbottabad hideout: Americas, News |work=India Today |date=9 September 2012 |access-date=21 December 2013 |archive-date=15 August 2022 |archive-url=https://web.archive.org/web/20220815025035/https://www.indiatoday.in/world/americas/story/us-had-planned-air-strike-to-level-osama-abbottabad-hideout-115557-2012-09-09 |url-status=live}}</ref>

On 28 March 2013, two B-2s flew a round trip of {{convert|13000|mi|km|abbr=out}} from Whiteman Air Force base in Missouri to South Korea, dropping dummy ordnance on the Jik Do target range. The mission, part of the annual South Korean–U.S. military exercises, was the first time that B-2s overflew the Korean Peninsula. Tensions between the Koreas were high; North Korea protested against the B-2's participation and made threats of retaliatory nuclear strikes against South Korea and the United States.<ref>[http://www.globalpost.com/dispatch/news/afp/130328/us-flies-stealth-bombers-over-south-korea US flies stealth bombers over South Korea] {{webarchive|url=https://web.archive.org/web/20130403212710/http://www.globalpost.com/dispatch/news/afp/130328/us-flies-stealth-bombers-over-south-korea |date= 3 April 2013}} Agence France-Presse, 28 April 2013.</ref><ref>[https://www.cbsnews.com/news/us-flies-b-2-stealth-bombers-to-s-korea-in-extended-deterrence-mission-aimed-at-north/ U.S. flies B-2 stealth bombers to S. Korea in "extended deterrence mission" aimed at North]  CBS News, 28 March 2013.</ref>

On 18 January 2017, two B-2s attacked an ISIS training camp {{convert|30|km|mi|order=flip}} southwest of [[Sirte, Libya]], killing around 85 militants. The B-2s together dropped 108 {{convert|500|lb|kg|adj=on}} precision-guided [[Joint Direct Attack Munition]] (JDAM) bombs. These strikes were followed by an [[General Atomics MQ-9 Reaper|MQ-9 Reaper]] unmanned aerial vehicle firing Hellfire missiles. Each B-2 flew a 33-hour, round-trip mission from Whiteman Air Force Base, Missouri with four or five (accounts differ) refuelings during the trip.<ref>{{cite web |url=http://www.foxnews.com/world/2017/01/19/b-2-bombers-kill-nearly-100-isis-terrorists-in-libya.html |title=B-2 bombers kill nearly 100 ISIS terrorists in Libya |first=Lucas |last=Tomlinson |date=19 January 2017 |publisher=Fox News |access-date=2 July 2018 |archive-date=2 July 2018 |archive-url=https://web.archive.org/web/20180702122101/http://www.foxnews.com/world/2017/01/19/b-2-bombers-kill-nearly-100-isis-terrorists-in-libya.html |url-status=live}}</ref><ref>{{cite magazine |last1=Langewiesche |first1=William |title=An Extraordinarily Expensive Way to Fight ISIS |url=https://www.theatlantic.com/magazine/archive/2018/07/william-langewiesche-b-2-stealth-bomber/561719/ |magazine=The Atlantic |date=July–August 2018 |access-date=2 July 2018 |archive-date=27 June 2018 |archive-url=https://web.archive.org/web/20180627111647/https://www.theatlantic.com/magazine/archive/2018/07/william-langewiesche-b-2-stealth-bomber/561719/ |url-status=live}}</ref>

=== 2020s ===
On 16 October 2024, B-2As carried out strikes on weapons storage facilities in [[Yemen]], including underground facilities owned by the [[Houthi movement|Houthis]].<ref name=":0">{{Cite web |last=Liebermann |first=Oren |last2=Bertrand |first2=Natasha |last3=Britzky |first3=Haley |date=2024-10-16 |title=US B-2 bombers strike Iran-backed Houthis in Yemen |url=https://www.cnn.com/2024/10/16/politics/us-strikes-iran-backed-houthis-yemen/index.html |access-date=2024-10-17 |website= CNN Politics |language=en}}</ref> Five hardened underground weapons storage locations were struck as part of the campaign against the Houthis for attacking international shipping during the [[Red Sea crisis]]. It was believed the strikes also served as a warning to Iran, demonstrating the stealth bomber's ability to destroy targets buried underground.<ref>[https://abcnews.go.com/International/wireStory/us-long-range-2-stealth-bombers-target-underground-114880390 US long-range B-2 stealth bombers target underground bunkers of Yemen's Houthi rebels]. ''[[ABC News (United States)|ABC News]]''. 16 October 2024.</ref><ref>[https://www.twz.com/air/b-2-spirits-just-sent-a-very-ominous-message-to-iran-that-only-they-can B-2 Spirits Just Sent A Very Ominous Message To Iran]. ''The War Zone''. 17 October 2024.</ref> [[RAAF Base Tindal]] in the [[Northern Territory]], Australia was used as a staging ground for the strikes.<ref>{{Cite news |date=2024-10-18 |title=Australian air base used as staging ground for US strike on Houthi weapon stores |url=https://www.abc.net.au/news/2024-10-18/australian-airbase-used-in-us-strike-on-houthi-stores-yemen/104490578 |access-date=2024-10-18 |work=ABC News |language=en-AU}}</ref>

==Operators==
[[File:B-2 Spirit bombing, 1994.jpg|thumb|upright|In a 1994 [[live fire exercise]] near [[Point Mugu]], California, a B-2 drops 47 individual {{convert|500|lb|kg|abbr=on}} [[Mark 82 bomb|Mark 82]] bombs, which is more than half of a B-2's total ordnance payload.]]

'''[[United States Air Force]]''' (19 aircraft in active inventory)
:'''[[Air Force Global Strike Command]]'''
* [[509th Bomb Wing]] – [[Whiteman Air Force Base]], [[Missouri]] (18 B-2s)
::[[13th Bomb Squadron]] 2005–present
::325th Bomb Squadron 1998–2005
::[[393rd Bomb Squadron]] 1993–present
::[[394th Combat Training Squadron]] 1996–2018
:'''[[Air Combat Command]]'''
* [[53rd Wing]] – [[Eglin Air Force Base]], Florida
::[[72nd Test and Evaluation Squadron]] (Whiteman AFB, Missouri) 1998–present
* [[57th Wing]] – [[Nellis AFB]], [[Nevada]]
::[[325th Weapons Squadron]] – Whiteman AFB, Missouri 2005–present
::[[715th Weapons Squadron]] 2003–2005
:'''[[Air National Guard]]'''
* [[131st Bomb Wing]] (Associate) – Whiteman AFB, Missouri 2009–present
::[[110th Bomb Squadron]]
:'''[[Air Force Materiel Command]]'''
* [[412th Test Wing]] – [[Edwards Air Force Base]], California (has one B-2)
::[[419th Flight Test Squadron]] 1997–present
::[[420th Flight Test Squadron]] 1992–1997
:'''[[Air Force Systems Command]]'''
* 6510th Test Wing – Edwards AFB, California 1989–1992
::6520th Flight Test Squadron

==Accidents and incidents==
{{main|2008 Andersen Air Force Base B-2 accident}}
[[File:Crashed B-2.jpg|thumb|Wreckage of the [[2008 Andersen Air Force Base B-2 accident|2008 B-2 crash]]|upright=1.2]]

On 23 February 2008, B-2 "AV-12" ''Spirit of Kansas'' [[2008 Andersen Air Force Base B-2 accident|crashed on the runway]] shortly after takeoff from [[Andersen Air Force Base]] in [[Guam]].<ref name=Av_Week_crash>[https://archive.today/20130117211217/http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=defense&id=news/b2crsh02238.xml "B-2 Crashes on Takeoff From Guam."] ''Aviation Week'', 23 February 2008. Retrieved 13 September 2009.</ref> ''Spirit of Kansas'' had been operated by the [[393rd Bomb Squadron]], [[509th Bomb Wing]], [[Whiteman Air Force Base]], Missouri, and had logged 5,176 flight hours. The two-person crew ejected safely from the aircraft. The aircraft was destroyed, a [[hull loss]] valued at US$1.4&nbsp;billion.<ref>[https://www.usatoday.com/news/nation/2008-06-05-371843035_x.htm "Air Force: Sensor moisture caused 1st B-2 crash."] {{Webarchive|url=https://web.archive.org/web/20110604131825/http://www.usatoday.com/news/nation/2008-06-05-371843035_x.htm |date=4 June 2011}} ''USA Today'', 5 June 2008. Retrieved 16 February 2009.</ref><ref>[https://www.youtube.com/watch?v=8ZB-iziY2Bw "B-2 crash video."] {{Webarchive|url=https://web.archive.org/web/20170204000528/https://www.youtube.com/watch?v=8ZB-iziY2Bw&feature=related |date=4 February 2017}} YouTube. Retrieved 23 July 2009.</ref> After the accident, the USAF took the B-2 fleet off operational status for 53 days, returning on 15 April 2008.<ref>Linch, Airman 1st Class Stephen. [https://web.archive.org/web/20080422143614/http://www.af.mil/news/story.asp?id=123095213 "B-2s return to flight after safety pause."] ''US Air Force'', 21 April 2008. Retrieved 1 December 2010.</ref> The cause of the crash was later determined to be moisture in the aircraft's Port Transducer Units during air data calibration, which distorted the information being sent to the bomber's air data system. As a result, the flight control computers calculated an inaccurate airspeed, and a negative angle of attack, causing the aircraft to pitch upward 30 degrees during takeoff.<ref>[http://www.acc.af.mil/media/archives/story.asp?id=123101589 "B-2 accident report released."] {{webarchive|url=https://web.archive.org/web/20131005025858/http://www.acc.af.mil/media/archives/story.asp?id=123101589 |date=5 October 2013}} ''US Air Force'', 6 June 2008. Retrieved 20 March 2011.</ref> This was the first crash and loss of a B-2.

In February 2010, a serious incident involving a B-2 occurred at Andersen Air Force Base in Guam. The aircraft involved was AV-11 ''Spirit of Washington''. The aircraft was severely damaged by fire while on the ground and underwent 18 months of repairs to enable it to fly back to the mainland U.S. for more comprehensive repairs.<ref name="pacificnewscenter.com">jeremigio. [https://www.pncguam.com/wright-patterseon/ "B-2 Fire at AAFB Back in February of 2010 Was 'Horrific,' Not 'Minor'."] {{Webarchive|url=https://web.archive.org/web/20201022174614/https://www.pncguam.com/wright-patterseon/ |date=22 October 2020}} ''pncguam.com'', 31 August 2011. Retrieved 8 May 2020.</ref><ref>Mayer, Daryl. [http://www.wpafb.af.mil/news/story.asp?id=123269146 "Program office brings home 'wounded warrior'."] {{webarchive|url=https://web.archive.org/web/20141220041802/http://www.wpafb.af.mil/news/story.asp?id=123269146 |date=20 December 2014}} ''wpafb.af.mil.'' Retrieved: 5 January 2012.</ref> ''Spirit of Washington'' was repaired and returned to service in December 2013.<ref name="whitemanmil">{{cite web |author=Candy Knight |url=http://www.whiteman.af.mil/news/story.asp?id=123375147 |title="Spirit of Washington" rises from the ashes |publisher=Whiteman.af.mil |access-date=21 December 2013 |url-status=dead |archive-url=https://web.archive.org/web/20131224114456/http://www.whiteman.af.mil/news/story.asp?id=123375147 |archive-date=24 December 2013}}</ref><ref>Hennigan, W. J., "The $105M resurrection of a B-2 stealth bomber", ''[[Los Angeles Times]]'', 22 March 2014</ref> At the time of the accident, the USAF had no training to deal with tailpipe fires on the B-2s.<ref>{{cite web |url=http://www.flightglobal.com/news/articles/usaf-updates-firefighter-training-and-equipment-following-b-2-tailpipe-397472/ |title=USAF updates firefighter training and equipment following B-2 tailpipe fire |last1=Hemmerdinger |first1=Jon |date=27 March 2014 |website=FlightGlobal |access-date=27 March 2014 |archive-date=14 December 2014 |archive-url=https://web.archive.org/web/20141214154655/http://www.flightglobal.com/news/articles/usaf-updates-firefighter-training-and-equipment-following-b-2-tailpipe-397472/ |url-status=live}}</ref>

On the night of 13–14 September 2021, B-2 ''Spirit of Georgia'' made an emergency landing at Whiteman AFB. The aircraft landed and [[runway excursion|went off the runway]] into the grass and came to rest on its left side.<ref name="crash2021">{{cite web |last= |first= |date=September 2021 |title=B-2 Spirit sitting wing down after landing mishap |url=https://www.thedrive.com/the-war-zone/42392/damaged-b-2-spirit-is-sitting-wing-down-off-the-runway-after-landing-mishap |archive-url=https://web.archive.org/web/20220814204852/https://www.thedrive.com/the-war-zone/42392/damaged-b-2-spirit-is-sitting-wing-down-off-the-runway-after-landing-mishap |archive-date=14 August 2022 |publisher=The War Zone}}</ref> The cause was later determined to be faulty landing gear springs and "microcracking" in hydraulic connections on the aircraft. The lock link springs in the left landing gear had likely not been replaced in at least a decade, and produced about 11% less tension than specified. The "microcracking" reduced hydraulic support to the landing gear. These problems allowed the landing gear to fold upon landing. The accident resulted in a minimum of $10.1&nbsp;million in repair damages, but the final repair cost was still being determined in March 2022.<ref>{{Cite web |last=RIEDEL |first=ALEXANDER |date=March 18, 2022 |title=Faulty landing gear springs led to B-2 bomber crash last year, report finds |url=https://www.stripes.com/branches/air_force/2022-03-18/decade-old-landing-gear-springs-led-to-b2-crash-landing-5386748.html |access-date=2022-12-13 |website=Stars and Stripes |language=en |archive-date=12 December 2022 |archive-url=https://web.archive.org/web/20221212075639/https://www.stripes.com/branches/air_force/2022-03-18/decade-old-landing-gear-springs-led-to-b2-crash-landing-5386748.html |url-status=live}}</ref><ref>{{Cite web |last=Cocke |first=Robert P.M. |date=January 12, 2022 |title=United States Air Force / Abbreviated Aircraft Accident Investigation / B-2A, T/N 89-0129 / Whiteman Air Force Base, Missouri / 14 September 2021 |url=https://www.afjag.af.mil/Portals/77/AIB-Reports/2021/AAIB%20Report%20-%20B-2%20Mishap%20TN%2089-0129%20-%20FINAL.pdf |archive-url=https://web.archive.org/web/20220317215755/https://www.afjag.af.mil/Portals/77/AIB-Reports/2021/AAIB%20Report%20-%20B-2%20Mishap%20TN%2089-0129%20-%20FINAL.pdf |archive-date=March 17, 2022 |access-date=2022-12-13 |website=United States Air Force Judge Advocate General's Corps}}</ref>

On 10 December 2022, an in-flight malfunction aboard a B-2 forced an emergency landing at Whiteman AFB.<ref>{{Cite web |last=Helfrich |first=Emma |date=2022-12-12 |title=Runway At Whiteman AFB Remains Closed After B-2 Bomber Accident |url=https://www.thedrive.com/the-war-zone/runway-at-whiteman-afb-remains-closed-after-b-2-bomber-accident |access-date=2022-12-13 |website=The Drive |language=en |archive-date=13 December 2022 |archive-url=https://web.archive.org/web/20221213025316/https://www.thedrive.com/the-war-zone/runway-at-whiteman-afb-remains-closed-after-b-2-bomber-accident |url-status=live}}</ref> No personnel, including the flight crew, sustained injuries during the incident; there was a post-crash fire that was quickly put out.<ref>{{Cite web |last=Epstein |first=Jake |title=A B-2 stealth bomber's emergency landing sparked a fire and damaged the plane, but the crew walked away unharmed |url=https://www.businessinsider.com/b-2-stealth-bomber-damaged-emergency-landing-fire-crew-unharmed-2022-12 |access-date=2022-12-17 |website=Business Insider |language=en-US |archive-date=17 December 2022 |archive-url=https://web.archive.org/web/20221217042846/https://www.businessinsider.com/b-2-stealth-bomber-damaged-emergency-landing-fire-crew-unharmed-2022-12 |url-status=live}}</ref> Subsequently, all B-2s were grounded.<ref>{{cite web | url=https://www.cnn.com/2022/12/21/politics/air-force-b2-bomber-grounded/index.html | title=B-2 nuke bomber fleet is temporarily grounded due to safety issue &#124; CNN Politics | website=[[CNN]] | date=21 December 2022 | access-date=22 December 2022 | archive-date=22 December 2022 | archive-url=https://web.archive.org/web/20221222053248/https://www.cnn.com/2022/12/21/politics/air-force-b2-bomber-grounded/index.html | url-status=live}}</ref> On 18 May 2023, Air Force officials lifted the grounding without disclosing any details about what caused the incident, or what steps had been taken return the aircraft to operation.<ref>{{Cite web |last=Gordon |first=Chris |date=2023-05-18 |title=B-2 Safety Pause Lifted, Flights Set to Resume Within Days |url=https://www.airandspaceforces.com/b-2-safety-pause-lifted-flights-resume/ |access-date=2023-05-22 |website=Air And Space Forces Magazine |language=en-US |archive-date=23 May 2023 |archive-url=https://web.archive.org/web/20230523023257/https://www.airandspaceforces.com/b-2-safety-pause-lifted-flights-resume/ |url-status=live}}</ref> In May 2024, the Air Force announced the B-2 would be divested, as it had been deemed to be "uneconomical to repair." Although no cost estimate was provided, the decision was likely influenced by the coming introduction of the B-21 bomber; after the B-2 crash in 2010, it took almost four years and over $100 million to return the aircraft to service because not losing one of the few penetrating bombers in the inventory was considered necessary to justify the effort. However, the impending arrival of the B-21 and coming retirement of the B-2 sometime after 2029 likely made USAF leaders decide it wouldn't be worth the expense to repair it, only for it to soon be retired.<ref name="airforcemag13may24"/><ref>[https://www.defenseone.com/technology/2024/05/b-2-crashed-2022-wont-be-fixed-air-force-confirms/396519/ B-2 that caught fire in 2022 won’t be fixed, Air Force confirms]. ''Defense One''. 13 May 2024.</ref>{{failed verification|date=May 2024}}

==Aircraft on display==
[[File:B-2.jpg|thumb|Restored B-2 Spirit full-scale test unit on display at the [[National Museum of the United States Air Force]] ]]
No operational B-2s have been retired by the Air Force to be put on display. B-2s have made occasional appearances on ground display at various [[air show]]s.

B-2 test article (s/n AT-1000), the second of two built without engines or instruments and used for static testing, was placed on display in 2004 at the [[National Museum of the United States Air Force]] near [[Dayton, Ohio]].<ref name="nationalmuseum.af.mil">[http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=422 "Factsheet: Northrop B-2 Spirit."] {{webarchive|url=https://web.archive.org/web/20110929072204/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=422 |date=29 September 2011}} ''National Museum of the United States Air Force.'' Retrieved: 24 August 2011.</ref> The test article passed all structural testing requirements before the airframe failed.<ref name="nationalmuseum.af.mil"/> The museum's restoration team spent over a year reassembling the fractured airframe. The display airframe is marked to resemble ''Spirit of Ohio'' (S/N 82-1070), the B-2 used to test the design's ability to withstand extreme heat and cold.<ref name="nationalmuseum.af.mil"/> The exhibit features ''Spirit of Ohio''{{'}}s nose wheel door, with its ''Fire and Ice'' artwork, which was painted and signed by the technicians who performed the temperature testing.<ref name="nationalmuseum.af.mil"/> The restored test aircraft is on display in the museum's "Cold War Gallery".<ref>[http://www.nationalmuseum.af.mil/exhibits/coldwar/index.asp "Cold War Gallery."] {{webarchive|url=https://web.archive.org/web/20110815041028/http://www.nationalmuseum.af.mil/exhibits/coldwar/index.asp |date=15 August 2011}} ''National Museum of the United States Air Force.'' Retrieved: 24 August 2011.</ref>

==Specifications (B-2A Block 30)==
[[File:NORTHROP B-2.png|400px|right|Orthographically projected diagram of the B-2 Spirit]]
[[File:Valiant Shield - B2 Stealth bomber from Missouri leads ariel formation.jpg|thumb|A B-2 in formation flight with eight U.S. Navy [[McDonnell Douglas F/A-18 Hornet|F/A-18 Hornet]]s and [[Boeing F/A-18E/F Super Hornet|Super Hornets]]]]

{{Aircraft specs
|ref= USAF Fact Sheet,<ref name=B-2_AF_fact_sheet /> Pace,<ref name=Pace_appA>{{harvnb|Pace|1999|loc=Appendix A}}</ref> Spick,<ref name=Spick_p340-1 /> Northrop Grumman<ref group=notes>Maximum takeoff weight is classified; listed figure is based on statement from manufacturer that aircraft's payload capacity is at least 40,000 lb.</ref><ref>{{Cite web |title=B-2 Technical Details |url=https://www.northropgrumman.com/what-we-do/air/b-2-stealth-bomber/b-2-technical-details |access-date=2023-10-27 |website=Northrop Grumman |language=en}}</ref>
|prime units?= imp
<!--  General characteristics
-->
|genhide=

|crew= 2: pilot (left seat) and mission commander (right seat)
|capacity=
|length m= 21.0
|length ft= 69
|length in=
|length note=
|span m= 52.4
|span ft= 172
|span in=
|span note=
|height m= 5.18
|height ft= 17
|height in=
|height note=
|wing area sqm= 478
|wing area sqft= 5,140
|wing area note=
|airfoil=
|empty weight kg= 71,700
|empty weight lb= 158,000
|empty weight note=
|gross weight kg= 152,200
|gross weight lb= 336,500
|gross weight note=
|max takeoff weight kg= 170,600
|max takeoff weight lb= 376,000
|max takeoff weight note=
|fuel capacity= 167,000 pounds (75,750&nbsp;kg)
|more general=
<!--  Powerplant
-->
|eng1 number= 4
|eng1 name= [[General Electric F118]]-GE-100
|eng1 type= non-afterburning [[turbofan]]s
|eng1 kn= 77
|eng1 lbf= 17,300
|eng1 note=
|power original=
|thrust original=
<!--  Performance
-->
|perfhide=

|max speed kmh= 1,010
|max speed mph= 630
|max speed kts= 550
|max speed note= at {{cvt|40,000|ft|m}} altitude / Mach 0.95 at sea level<ref name=Pace_appA />
|cruise speed kmh= 900
|cruise speed mph= 560
|cruise speed kts= 487
|cruise speed note= at {{cvt|40,000|ft|m}} altitude
|stall speed kmh=
|stall speed mph=
|stall speed kts=
|stall speed note=
|never exceed speed kmh=
|never exceed speed mph=
|never exceed speed kts=
|never exceed speed note=
|minimum control speed kmh=
|minimum control speed mph=
|minimum control speed kts=
|minimum control speed note=
|range km=
|range miles=
|range nmi= 6,000
|range note=
|combat range km=
|combat range miles=
|combat range nmi=
|combat range note=
|ferry range km=
|ferry range miles=
|ferry range nmi=
|ferry range note=
|endurance=<!-- if range unknown -->
|ceiling m= 15,200
|ceiling ft= 50,000
|ceiling note=
|climb rate ms=
|climb rate ftmin=
|climb rate note=
|time to altitude=
|sink rate note=
|lift to drag=
|wing loading kg/m2= 329
|wing loading lb/sqft= 67.3
|wing loading note=
|disk loading kg/m2=
|disk loading lb/sqft=
|disk loading note=
|fuel consumption kg/km=
|fuel consumption lb/mi=
|power/mass=
|thrust/weight= 0.205

|more performance=
<!--  Armament
-->
|armament=* 2 internal bays for ordnance and payload with an official limit of {{convert|40000|lb|kg|abbr=on}}; maximum estimated limit is {{convert|50000|lb|kg|abbr=on}}<ref name=Spick_p340-1 />
** 80× {{cvt|500|lb|kg}} class bombs ([[Mark 82 bomb|Mk-82]], [[Joint Direct Attack Munition|GBU-38]]) mounted on Bomb Rack Assembly (BRA)
** 36× {{cvt|750|lb|kg}} CBU class bombs on BRA
** 16× {{cvt|2,000|lb|kg}} class bombs ([[Mark 84 bomb|Mk-84]], [[Joint Direct Attack Munition|GBU-31]]) mounted on Rotary Launcher Assembly (RLA)
** 16× [[B61 nuclear bomb|B61]] or [[B83 nuclear bomb|B83]] nuclear bombs on RLA (strategic mission)
** Standoff weapon: [[AGM-154]] Joint Standoff Weapon (JSOW) and [[AGM-158]] Joint Air-to-Surface Standoff Missile (JASSM)<ref name=JSOW>{{cite web|url=http://www.navy.mil/navydata/fact_display.asp?cid=2100&tid=300&ct=2|title=The US Navy – Fact File: AGM-154 Joint Standoff Weapon (JSOW) |author=Dan Petty|access-date=7 April 2016 |archive-date=2 April 2018|archive-url=https://web.archive.org/web/20180402225505/http://www.navy.mil/navydata/fact_display.asp?cid=2100&tid=300&ct=2|url-status=live}}</ref><ref name=JASSM>{{cite web|url=http://www.lockheedmartin.com/us/products/jassm.html|title=JASSM|access-date=7 April 2016|archive-date=4 June 2012|archive-url=https://web.archive.org/web/20120604195507/http://www.lockheedmartin.com/us/products/jassm.html|url-status=live}}</ref>
** 2× [[GBU-57]] Massive Ordnance Penetrator<ref name="MOP_capability">{{cite web |url=https://www.thedrive.com/the-war-zone/28076/new-video-of-b-2-bomber-dropping-mother-of-all-bunker-busters-sends-ominous-message |title=New Video Of B-2 Bomber Dropping Mother Of All Bunker Busters Sends Ominous Message |publisher=The War Zone |date=17 May 2019 |access-date=11 June 2020 |archive-date=29 May 2020 |archive-url=https://web.archive.org/web/20200529213910/https://www.thedrive.com/the-war-zone/28076/new-video-of-b-2-bomber-dropping-mother-of-all-bunker-busters-sends-ominous-message |url-status=live}}</ref>

|avionics=
}}

==Individual aircraft==
[[File:B2PlanView.jpg|thumb|''Spirit of Indiana'' sits on the [[Airport ramp|ramp]] at [[Andersen AFB]] in Guam on 23 June 2006]]
[[File:82-1068-B-2-Spirit-0349.jpg|thumb|right|''Spirit of New York'']]
[[File:B-2 Spirit 060810-F-6701P-004.jpg|thumb|B-2 in flight over the [[Mississippi River]] ([[St. Louis, Missouri|St. Louis]], Missouri) with the [[Gateway Arch]], [[Basilica of St. Louis, King of France|St. Louis Basilica]], and [[Busch Stadium]] in the background]]

{| class="wikitable"
|+Individual aircraft <br />Sources: B-2 Spirit (Pace),<ref>{{harvnb|Pace|1999|loc=Appendix}}</ref> Fas.org<ref>[https://fas.org/nuke/guide/usa/bomber/b-2.htm "B-2."] {{Webarchive|url=https://web.archive.org/web/20150409004120/https://fas.org/nuke/guide/usa/bomber/b-2.htm |date=9 April 2015}} ''fas.org''. Retrieved 16 June 2010.</ref>
|-
!style=width:50px; | Air Vehicle No.
!style=width:50px; | Block No.<ref>All 21 copies brought to Block 30 standard.</ref>
!style=width:55px; | USAF s/n
!style=width:150px; | Formal name
!Time in service, status
|-
| AV-1 || align=center|Test/30 ||{{USAF serial|82|1066}} || ''Spirit of America'' || 14 July 2000 – Active<ref>[https://fas.org/nuke/guide/usa/bomber/man-ac-b2-000714.htm "Air Force names final B-2 bomber 'Spirit of America"] {{Webarchive|url=https://web.archive.org/web/20150409015830/https://fas.org/nuke/guide/usa/bomber/man-ac-b2-000714.htm |date=9 April 2015}}. ''fas.org'', 14 July 2000. Retrieved 16 June 2010.</ref>
|-
| AV-2 || align=center|Test/30 ||{{USAF serial|82|1067}} || ''Spirit of Arizona'' || 4 December 1997 – Active
|-
| AV-3 || align=center|Test/30 ||{{USAF serial|82|1068}} || ''Spirit of New York'' || 10 October 1997 – Active
|-
| AV-4 || align=center|Test/30||{{USAF serial|82|1069}} || ''Spirit of Indiana'' || 22 May 1999 – Active
|-
| AV-5 || align=center|Test/20 ||{{USAF serial|82|1070}} || ''Spirit of Ohio'' || 18 July 1997 – Active
|-
| AV-6 || align=center|Test/30 ||{{USAF serial|82|1071}} || ''Spirit of Mississippi'' || 23 May 1997 – Active
|-
| AV-7 || align=center|10 ||{{USAF serial|88|0328}} || ''Spirit of Texas'' || 21 August 1994 – Active
|-
| AV-8 || align=center|10 ||{{USAF serial|88|0329}} || ''Spirit of Missouri'' || 31 March 1994 – Active
|-
| AV-9 || align=center|10 ||{{USAF serial|88|0330}} || ''Spirit of California'' || 17 August 1994 – Active
|-
| AV-10 || align=center|10 ||{{USAF serial|88|0331}} || ''Spirit of South Carolina'' || 30 December 1994 – Active
|-
| AV-11 || align=center|10 ||{{USAF serial|88|0332}} || ''Spirit of Washington'' || 29 October 1994 – Severely damaged by fire in February 2010,<ref name="pacificnewscenter.com"/> repaired<ref name="whitemanmil"/>
|-
| AV-12 || align=center|10 ||{{USAF serial|89|0127}} || ''Spirit of Kansas'' || 17 February 1995 – 23 February 2008, [[Andersen Air Force Base B-2 accident|crashed]]<ref name=Av_Week_crash/>
|-
| AV-13 || align=center|10 ||{{USAF serial|89|0128}} || ''Spirit of Nebraska'' || 28 June 1995 – Active
|-
| AV-14 || align=center|10 ||{{USAF serial|89|0129}} || ''Spirit of Georgia'' || 14 November 1995 – Suffered damage to the wing following a landing gear collapse in September 2021.<ref>{{cite news |last1=Losey |first1=Stephen |title=Old, weak landing gear springs led to a B-2's $10M skid off the runway |url=https://www.defensenews.com/news/your-air-force/2022/03/17/old-weak-landing-gear-springs-led-to-a-b-2s-10m-skid-off-the-runway/ |access-date=7 October 2022 |agency=Defense News |publisher=Sightline Media Group |date=17 March 2022 |archive-date=16 October 2023 |archive-url=https://web.archive.org/web/20231016213635/https://www.defensenews.com/news/your-air-force/2022/03/17/old-weak-landing-gear-springs-led-to-a-b-2s-10m-skid-off-the-runway/ |url-status=live}}</ref> Undergoing repairs at [[United States Air Force Plant 42|Plant 42]]<ref>{{cite news |last1=Trevithick |first1=Joseph |title=Damaged B-2 Returns To Palmdale For Repairs A Year After Landing Mishap |url=https://www.thedrive.com/the-war-zone/bandaged-b-2-bomber-returns-to-its-birth-place-for-major-repairs |access-date=7 October 2022 |agency=The War Zone |date=22 September 2022 |archive-date=7 October 2022 |archive-url=https://web.archive.org/web/20221007170956/https://www.thedrive.com/the-war-zone/bandaged-b-2-bomber-returns-to-its-birth-place-for-major-repairs |url-status=live}}</ref>
|-
| AV-15 || align=center|10 ||{{USAF serial|90|0040}} || ''Spirit of Alaska'' || 24 January 1996 – Active
|-
| AV-16 || align=center|10 ||{{USAF serial|90|0041}} || ''Spirit of Hawaii'' || 10 January 1996 – 10 December 2022,<ref>{{Cite web |last=Cohen |first=Rachel |date=2022-12-12 |title=B-2 stealth bomber damaged in Missouri emergency landing |url=https://www.airforcetimes.com/news/your-air-force/2022/12/12/b-2-stealth-bomber-damaged-in-emergency-landing-at-whiteman/ |access-date=2022-12-15 |website=Air Force Times |language=en |archive-date=16 October 2023 |archive-url=https://web.archive.org/web/20231016213636/https://www.airforcetimes.com/news/your-air-force/2022/12/12/b-2-stealth-bomber-damaged-in-emergency-landing-at-whiteman/ |url-status=live}}</ref> crashed<ref name="airforcemag13may24"/>
|-
| AV-17 || align=center|20 ||{{USAF serial|92|0700}} || ''Spirit of Florida'' || 3 July 1996 – Active
|-
| AV-18 || align=center|20 ||{{USAF serial|93|1085}} || ''Spirit of Oklahoma'' || 15 May 1996 – Active, Flight Test
|-
| AV-19 || align=center|20 ||{{USAF serial|93|1086}} || ''Spirit of Kitty Hawk'' || 30 August 1996 – Active
|-
| AV-20 || align=center|30 ||{{USAF serial|93|1087}} || ''Spirit of Pennsylvania'' || 5 August 1997 – Active
|-
| AV-21 || align=center|30 ||{{USAF serial|93|1088}} || ''Spirit of Louisiana'' || 11 November 1997 – Active
|-
|colspan="4"|AV-22 through AV-165 || Cancelled
|}

==Notable appearances in media==
<!-- ===============({{NoMoreCruft}})===============-->
<!-- Please READ [[Wikipedia:WikiProject Aircraft/page content#Popular culture]] and [[Wikipedia:WikiProject Military history/Style guide#Popular culture]] before adding any "Popular culture" items.

Please do not add the many minor appearances of the aircraft. This section is only for major cultural appearances where the aircraft plays a MAJOR part in the story line, or has an "especially notable" role in what is listed. A verifiable source proving the appearance's notability may be required. Random cruft, including ALL Ace Combat, Video Game appearances, Transformers toyline appearances, Battlefield, and Metal Gear Solid appearances, and ALL anime/fiction lookalike speculation, WILL BE removed.

If your item has been removed, please discuss it on the talk page FIRST. A verifiable source proving the appearance's notability may be required. If a consensus is reached to include your item, a regular editor of this page will add it back. Thank you for your cooperation.-->
<!-- ===============({{NoMoreCruft}})=============== -->
<!--
Read note at top about notability; take any potentially contentious submissions to the talk page, including HULK, IRON MAN. -->
{{Main|Aircraft in fiction#B-2 Spirit}}

==See also==
{{Portal|Aviation}}
{{aircontent
|see also=<!-- other related articles that have not already linked: -->
* [[Northrop YB-49]]
* [[Northrop Grumman B-21 Raider]]
|related=<!-- designs which were developed into or from this aircraft: -->
|similar aircraft=<!-- aircraft that are of similar role, era, and capability this design: -->
|lists=<!-- relevant lists that this aircraft appears in: -->
* [[List of active United States military aircraft]]
* [[List of bomber aircraft]]
* [[List of flying wing aircraft]]
* [[List of megaprojects#Aerospace projects|List of aerospace megaprojects]]
* [[List of military electronics of the United States]]
}}

===Notes===
{{reflist|group=notes}}

==References==
{{Reflist|30em}}

===Bibliography===
* [https://archive.today/20120802081022/http://www.gao.gov/cgi-bin/getrpt?NSIAD-96-192 "Air Force, Options to Retire or Restructure the Force Would Reduce Planned Spending, NSIAD-96-192."] ''US General Accounting Office'', September 1996.
* {{citation |last=Boyne |first= Walter J. |title=Air Warfare: an International Encyclopedia: A-L |location= Santa Barbara, California |publisher= ABC-CLIO |year= 2002 |isbn= 978-1-57607-345-2}}
* {{citation |last=Chudoba |first= Bernd |title=Stability and Control of Conventional and Unconventional Aircraft Configurations: A Generic Approach |location= Stoughton, Wisconsin |publisher= Books on Demand |year= 2001 |isbn=978-3-83112-982-9}}
* Crickmore, Paul and Alison J. Crickmore, "Nighthawk F-117 Stealth Fighter". North Branch, Minnesota: Zenith Imprint, 2003. {{ISBN|0-76031-512-4}}.
* Croddy, Eric and James J. Wirtz. ''Weapons of Mass Destruction: An Encyclopedia of Worldwide Policy, Technology, and History, Volume 2''. Santa Barbara, California: ABC-CLIO, 2005. {{ISBN|1-85109-490-3}}.
* Dawson, T.W.G., G.F. Kitchen and G.B. Glider. [http://www.nationalarchives.gov.uk/catalogue/displaycataloguedetails.asp?CATLN=6&CATID=4943225&SearchInit=4&SearchType=6&CATREF=AVIA+6%2F20895 ''Measurements of the Radar Echoing Area of the Vulcan by the Optical Simulation Method.''] Farnborough, Hants, UK: Royal Aircraft Establishment, September 1957 National Archive Catalogue file, AVIA 6/20895
* {{citation |editor-last=Donald |editor-first=David |title=Black Jets: The Development and Operation of America's Most Secret Warplanes |location= Norwalk, Connecticut |publisher=AIRtime |year= 2003 |isbn= 978-1-880588-67-3}}
* {{citation |last=Donald |first=David |title=The Pocket Guide to Military Aircraft: And the World's Airforces |location= London |publisher=Octopus Publishing Group |year=2004 |isbn= 978-0-681-03185-2}}
* Eden, Paul. "Northrop Grumman B-2 Spirit". ''Encyclopedia of Modern Military Aircraft''. New York: Amber Books, 2004. {{ISBN|1-904687-84-9}}.
* {{citation |last=Evans |first=Nicholas D. |title=Military Gadgets: How Advanced Technology is Transforming Today's Battlefield – and Tomorrow's |location=Upper Saddle River, New Jersey |publisher=FT Press |year=2004 |isbn=978-0-1314-4021-0 |url=https://archive.org/details/militarygadgetsh0000evan}}
* {{citation |editor-last=Fitzsimons |editor-first= Bernard |title=Illustrated Encyclopedia of 20th Century Weapons and Warfare |volume=21 |location= London |publisher= Phoebus |year= 1978 |isbn= 978-0-8393-6175-6}}
* Goodall, James C. "The Northrop B-2A Stealth Bomber." ''America's Stealth Fighters and Bombers: B-2, F-117, YF-22, and YF-23''. St. Paul, Minnesota: MBI Publishing Company, 1992. {{ISBN|0-87938-609-6}}.
* {{citation |last1=Griffin |first1=John |last2=Kinnu |first2=James |url=http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA464771&Location=U2&doc=GetTRDoc.pdf |archive-url=https://web.archive.org/web/20090822023730/http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA464771&Location=U2&doc=GetTRDoc.pdf |url-status=dead |archive-date=22 August 2009 |title=B-2 Systems Engineering Case Study |location=Dayton, Ohio |publisher= Air Force Center for Systems Engineering, Air Force Institute of Technology, Wright Patterson Air Force Base |year=2007}}
* {{citation |last1=Moir |first1= Ian |last2= Seabridge |first2=Allan G. |title=Aircraft Systems: Mechanical, Electrical and Avionics Subsystems Integration |location=Hoboken, New Jersey |publisher= John Wiley & Sons |year= 2008 |isbn=978-0-4700-5996-8}}
* {{citation |last=Pace |first=Steve |title=B-2 Spirit: The Most Capable War Machine on the Planet |location= New York |publisher=McGraw-Hill |year=1999 |isbn= 978-0-07-134433-3}}
* Pelletier, Alain J. "Towards the Ideal Aircraft: The Life and Times of the Flying Wing, Part Two". ''[[Air Enthusiast]]'', No. 65, September–October 1996, pp.&nbsp;8–19. {{ISSN|0143-5450}}.
* {{citation |last=Richardson |first=Doug |title=Stealth Warplanes |location=London |publisher=Salamander Books Ltd |year= 2001 |isbn= 978-0-7603-1051-9}}
* {{citation |last1=Rich |first1=Ben R. |last2=Janos |first2=Leo |title=Skunk Works: A Personal Memoir of My Years of Lockheed |location=Boston |publisher=Little, Brown & Company |year=1996 |isbn=978-0-3167-4300-6 |url-access=registration |url=https://archive.org/details/skunkworks00benr}}
* {{Citation |last=Rich |first=Ben |title=Skunk Works |location=New York |publisher=Back Bay Books |year=1994 |isbn=978-0-316-74330-3 |url=https://archive.org/details/skunkworks00benr}}
* {{citation |last1=Rip |first1=Michael Russell |last2=Hasik |first2=James M. |title=The Precision Revolution: Gps and the Future of Aerial Warfare |location= Annapolis, Maryland |publisher=Naval Institute Press |year= 2002 |isbn= 978-1-5575-0973-4}}
* {{citation |last=Siuru |first= William D. |title=Future Flight: The Next Generation of Aircraft Technology |location= New York |publisher=McGraw-Hill Professional |year= 1993 |isbn= 978-0-8306-4376-9}}
* {{citation |last=Sorenson |first=David, S. |title=The Politics of Strategic Aircraft Modernization |location= New York |publisher=Greenwood |year= 1995 |isbn=978-0-275-95258-7}}
* {{citation |last=Spick |first= Mike |title=B-2 Spirit, The Great Book of Modern Warplanes |location=St. Paul, Minnesota |publisher= MBI |year= 2000 |isbn= 978-0-7603-0893-6}}
* {{citation |last=Sweetman |first=Bill |title=Lockheed Stealth |location= North Branch, Minnesota |publisher= Zenith Imprint |year= 2005 |isbn= 978-0-7603-1940-6}}
* Sweetman, Bill. "Inside the stealth bomber". Zenith Imprint, 1999. {{ISBN|1610606892}}.
* {{citation |last= Tucker |first= Spencer C |title=The Encyclopedia of Middle East Wars: The United States in the Persian Gulf, Afghanistan, and Iraq Conflicts, Volume 1 |location= Santa Barbara, California |publisher=ABC-CLIO |year= 2010 |isbn= 978-1-8510-9947-4}}
* {{citation |last=Withington |first=Thomas |title=B-1B Lancer Units in Combat |location= Botley Oxford, UK |publisher=Osprey |year= 2006 |isbn= 978-1-8417-6992-9}}

==Further reading==
* Richardson, Doug. ''Northrop B-2 Spirit'' (Classic Warplanes). New York: Smithmark Publishers Inc., 1991. {{ISBN|0-8317-1404-2}}.
* [[Bill Sweetman|Sweetman, Bill]]. ''Inside the Stealth Bomber''. St. Paul, Minnesota: MBI Publishing, 1999. {{ISBN|0-7603-0627-3}}.
* Winchester, Jim, ed. "Northrop B-2 Spirit". ''Modern Military Aircraft'' (Aviation Factfile). Rochester, Kent, UK: Grange Books plc, 2004. {{ISBN|1-84013-640-5}}.
* ''The World's Great Stealth and Reconnaissance Aircraft''. New York: Smithmark, 1991. {{ISBN|0-8317-9558-1}}.

==External links==
{{Commons|Northrop Grumman B-2 Spirit}}
* [https://www.af.mil/About-Us/Fact-Sheets/Display/Article/104482/b-2-spirit/ B-2 Spirit fact sheet] and [https://web.archive.org/web/20090726182224/http://www.af.mil/photos/mediagallery.asp?galleryID=14 gallery on U.S. Air Force site]
* [http://www.as.northropgrumman.com/products/b2spirit/index.html B-2 Spirit page on Northrop Grumman site] {{Webarchive|url=https://web.archive.org/web/20121103155129/http://www.as.northropgrumman.com/products/b2spirit/index.html |date=3 November 2012}}
* [https://www.howitworksdaily.com/b-2-stealth-bomber/ B-2 Stealth Bomber article on How It Works Daily]
* [https://theaviationgeekclub.com/?s=b-2+spirit B-2 Spirit News Articles]

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