View source for Northrop Grumman X-47B

{{Distinguish|Boeing F-47}}
{{short description|Unmanned combat air vehicle demonstrator built by Northrop Grumman}}
{{Use dmy dates|date=October 2019}}
<!-- This article is a part of [[Wikipedia:WikiProject Aircraft]]. Please see [[Wikipedia:WikiProject Aircraft/page content]] for recommended layout. -->
{{Infobox aircraft
 |name = X-47B UCAS-D
 |image = File:X-47B operating in the Atlantic Test Range (modified).jpg
 |caption = An X-47B demonstrator over the [[U.S. Navy]]'s [[Atlantic Test Range]] 
 |type = {{plainlist|
*[[Unmanned combat aerial vehicle]]
*[[Technology demonstrator]]}}
 |national_origin = [[United States]]
 |manufacturer = [[Northrop Grumman]]
 |designer = <!--only appropriate for single designers, not project leaders-->
 |first_flight = 4 February 2011
 |introduction = <!--date the aircraft entered or will enter military or revenue service-->
 |retired = <!--date the aircraft left military or revenue service. If vague or multiples, it probably should be skipped-->
 |status = Active<!--in most cases, this field is redundant; use it sparingly -->
 |primary_user = [[United States Navy]]
 |more_users = <!--limited to three "more users" total; please list with {{plainlist}}-->
 |produced = 
 |number_built = 2
 |program cost= US$813 million (2012 estimate)<ref name=MoneyMoney/>
 |unit cost = <!-- incremental or flyaway cost for military aircraft or retail price for commercial aircraft. -->
 |developed_from = [[Northrop Grumman X-47A Pegasus]] <!-- the aircraft which formed the basis for the topic type -->
 |variants = <!-- variants OF the topic type -->
 |developed_into = 
}}

The '''Northrop Grumman X-47B''' is a [[technology demonstration|demonstration]] [[unmanned combat aerial vehicle]] (UCAV) designed for [[aircraft carrier]]-based operations. Developed by the American defense technology company [[Northrop Grumman]], the X-47 project began as part of [[Defense Advanced Research Project Agency|DARPA]]'s [[Joint Unmanned Combat Air Systems|J-UCAS]] program, and subsequently became part of the [[United States Navy]]'s [[Unmanned Combat Air System Demonstrator program|Unmanned Combat Air System Demonstration]] (UCAS-D) program. The X-47B is a tailless [[jet engine|jet]]-powered [[blended wing body|blended-wing-body]] aircraft capable of semi-autonomous operation and [[aerial refueling]].<ref name=EatFuel>{{cite web|url=http://www.popsci.com/look-autonomous-drone-eat-fuel-sky|title=Watch this autonomous drone eat fuel|work=[[Popular Science]]|date=17 April 2015|access-date=18 April 2015}}</ref>

The X-47B first flew in 2011, and {{as of|2015|lc=on}}, its two active demonstrators had undergone extensive flight and operational integration testing, having successfully performed a series of land- and carrier-based demonstrations.<ref name="carrier">{{cite web | url=https://abcnews.go.com/m/story?id=19173706&sid=81 | title=U.S. Launches Drone From Aircraft Carrier | publisher=ABC|date=15 May 2013|access-date=15 May 2013}}</ref><ref name=BBC11July2013/> In August 2014, the US Navy announced that it had integrated the X-47B into carrier operations alongside manned aircraft,<ref>{{cite web|url=http://foxtrotalpha.jalopnik.com/navy-makes-history-with-integrated-unmanned-manned-carr-1622988833/+ballaban|publisher=Jalopnik|date=17 August 2014|title=Navy Makes history with integrated unmanned manned carrier operations|access-date=17 August 2014}}</ref> and by May 2015 the primary test program was declared complete.<ref name=TestsDone>{{cite web|url=http://news.usni.org/2015/05/01/forbes-calls-on-secnav-mabus-to-extend-x-47b-testing|title=Forbes Calls on SECNAV Mabus to Extend X-47B Testing|publisher=[[United States Naval Institute]]|date=1 May 2015|access-date=8 September 2015}}</ref><ref>{{cite magazine|url=https://www.wired.com/dangerroom/2012/07/x47b/|title=Exclusive Pics: The Navy's Unmanned, Autonomous 'UFO'|magazine=Wired|date=31 July 2012|access-date=7 July 2013}}</ref><ref name=2023Perhaps>{{cite web|url=https://www.engadget.com/2015/02/05/drone-project-pushed-back-to-2016/|title=The Navy's unmanned drone project gets pushed back a year|publisher=[[Engadget]]|date=5 February 2015|access-date=10 February 2015}}</ref> The X-47B demonstrators themselves were intended to become museum exhibits after completing flight testing, but the Navy later decided to maintain them in flying condition pending further development.<ref name=Museum>{{cite web|url=http://www.huffingtonpost.co.uk/2015/04/17/the-us-navy-ufo-drone-might-be-amazing-but-its-heading-to-a-museum_n_7084990.html|title=The US Navy's 'UFO' Drone Might Be Impressive But It's Heading to a Museum|work=[[Huffington Post UK]]|date=17 April 2015|access-date=18 April 2015}}</ref><ref name="Lifeline2015">{{cite web |date=8 July 2015 |title=Northrop Grumman's Naval Combat Drones Get Lifeline (UPDATED) |url=https://www.nationaldefensemagazine.org/articles/2015/7/7/northrop-grummans-naval-combat-drones-get-lifeline-updated |url-status=live |archive-url=https://web.archive.org/web/20230601184427/https://www.nationaldefensemagazine.org/articles/2015/7/7/northrop-grummans-naval-combat-drones-get-lifeline-updated |archive-date=1 June 2023 |access-date=23 October 2023 |work=National Defense Magazine}}</ref>

==Design and development==
===Origins===
[[File:X-47B First to Complete Autonomous Aerial Refueling.webm|thumb|Video of aerial refueling of an X-47B in April 2015]]

The US Navy did not commit to practical UCAS efforts until 2000, when it awarded contracts of US$2 million each to [[Boeing]] and Northrop Grumman for a 15-month concept-exploration program.<ref>[http://www.defenselink.mil/releases/release.aspx?releaseid=2527 "DARPA And Navy Select Naval UCAV Contractors"]. US Department of Defense. 20 June 2000. Retrieved 30 November 2012.</ref> Design considerations for a naval UCAV included dealing with the corrosive [[seawater|saltwater]] environment, deck handling for launch and recovery, command and control system integration, and operation in an aircraft carrier's high-[[electromagnetic]]-interference environment. The Navy was interested in using UCAVs for reconnaissance, to penetrate protected airspace and identify targets for follow-on attacks.<ref>''[[Aviation Week & Space Technology]]''. "Tailless Tailhooker: Autonomous U.S. Navy X-plane flight marks sea change toward unmanned carrier aviation". 14 February 2011. p. 28.</ref>
Northrop Grumman's proof-of-concept [[X-47A Pegasus]], which provided the basis for the X-47B, first flew in 2003.<ref>{{Cite web |title=Unmanned Aircraft Systems Roadmap, 2005–2030 |url=https://apps.dtic.mil/sti/tr/pdf/ADA445081.pdf |access-date=18 August 2024 |website=[[Defense Technical Information Center]] (DTIC) |publisher=Office of the Secretary of Defense |page=11 |publication-date=2005}}</ref> The J-UCAS program was terminated in February 2006 following the [[Quadrennial Defense Review]]. The US Air Force and Navy proceeded with their own UAV programs. The Navy selected Northrop Grumman's X-47B as its unmanned combat air system demonstrator (UCAS-D) program.<ref name="AW0111"/> To provide realistic testing, the demonstrator was built to be the same size and weight as the projected operational craft, with a full-sized weapons bay capable of carrying existing missiles.<ref>[https://www.theregister.co.uk/2008/12/18/x47b_rollout_ceremony/ "US Navy's robot stealth carrier plane unveiled"]. ''The Register''. 18 December 2008. Retrieved 3 February 2013.</ref><ref>[http://www.is.northropgrumman.com/systems/nucasx47b.html "Northrop Grumman Integrated Systems X-47B UCAS overview"] {{webarchive|url=https://web.archive.org/web/20090514184353/http://www.is.northropgrumman.com/systems/nucasx47b.html |date=14 May 2009 }}. Northrop Grumman Integrated Systems. Retrieved 17 June 2013.</ref><ref>[http://www.irconnect.com/noc/press/pages/news_releases.html?d=156493 "Photo Release -- Northrop Grumman Reveals First Navy Unmanned Combat Aircraft"] {{webarchive|url=https://web.archive.org/web/20100328043325/http://www.irconnect.com/noc/press/pages/news_releases.html?d=156493 |date=28 March 2010 }}. Northrop Grumman. 16 December 2008. Retrieved 3 February 2013.</ref> The X-47B industry team included subcontractors [[Lockheed Martin]], [[Pratt & Whitney]], [[GKN|GKN Aerospace]], [[Eaton Corporation|Eaton]], [[General Electric]], [[UTC Aerospace Systems]], [[Dell]], [[Honeywell Aerospace Technologies|Honeywell]], [[Moog Inc.|Moog]], [[Wind River Systems|Wind River]], [[Parker Hannifin|Parker Aerospace]], [[Dover Corporation|Sargent Aerospace & Defense]], and [[Rockwell Collins]]. The X-47B prototype rolled out from [[Air Force Plant 42]] in [[Palmdale, California]], on 16 December 2008. Its first flight was planned for November 2009, but the project fell behind schedule. On 29 December 2009, Northrop Grumman oversaw towed taxi tests of the aircraft at the Palmdale facility, with it taxiing under its own power for the first time in January 2010.<ref name="AW0111">{{cite journal |last=Morring |first=Frank |date=11 January 2010 |title=Taxi Tests for UCAS-D |journal=Aviation Week |publisher=McGraw-Hill |page=15}}</ref>

===Flight testing===
[[File:X-47B 110204-F-1162D-119.jpg|thumb|right|The X-47B's first takeoff at [[Edwards Air Force Base]], [[California]], on 4 February 2011]]
[[File:U.S. Sailors move a U.S. Navy X-47B Unmanned Combat Air System demonstrator aircraft onto an aircraft elevator aboard the aircraft carrier USS George H.W. Bush (CVN 77) May 14, 2013, in the Atlantic Ocean 130514-N-FU443-025.jpg|thumb|right|An X-47B with folded wings on the aircraft elevator of [[USS George H.W. Bush|''George H.W. Bush'']] on 14 May 2013]]
[[File:An X-47B Unmanned Combat Air System demonstrator launches from the aircraft carrier USS George H.W. Bush (CVN 77) May 14, 2013, in the Atlantic Ocean 130514-N-UZ648-182.jpg|thumb|right|An X-47B launches from ''George H.W. Bush'' on 14 May 2013]]
[[File:A U.S. Navy X-47B Unmanned Combat Air System makes an arrested landing aboard the aircraft carrier USS George H.W. Bush (CVN 77) as the ship conducts flight operations in the Atlantic Ocean off the coast of Vir 130710-N-LE576-002.jpg|thumbnail|right|An X-47B makes a successful arrested landing on ''George H.W. Bush'' on 10 July 2013]]

The first flight of the X-47B demonstrator, designated Air Vehicle 1 (AV-1), took place at [[Edwards Air Force Base|Edwards Air Force Base, California]], on 4 February 2011.<ref>[http://www.aviationweek.com/aw/generic/story.jsp?id=news/awx/2011/02/04/awx_02_04_2011_p0-287709.xml&headline=Northrop%20UCAS-D%20Completes%20First%20Flight&channel=defense "Northrop UCAS-D Completes First Flight"]{{dead link|date=February 2018 |bot=InternetArchiveBot |fix-attempted=yes }}. ''Aviation Week''. 4 February 2011. Retrieved 11 July 2013.</ref><ref>[https://www.af.mil/News/story/id/123241594/ "Edwards flight engineers perform first X-47B flight"]. US Air Force. 7 February 2011. Retrieved 11 July 2013.</ref>
It first flew in cruise configuration with its landing gear retracted on 30 September 2011.<ref name=msn20111012>{{cite news |last=Roach |first=John |title=UFO-like drone hits cruise mode |url=http://futureoftech.msnbc.msn.com/_news/2011/10/10/8253784-ufo-like-drone-hits-cruise-mode |date=11 October 2011 |access-date=5 January 2013 |publisher=MSNBC |url-status=dead |archive-url=https://web.archive.org/web/20120118182615/http://futureoftech.msnbc.msn.com/_news/2011/10/10/8253784-ufo-like-drone-hits-cruise-mode |archive-date=18 January 2012 |df=dmy-all }}</ref> A second X-47B demonstrator, designated AV-2, conducted its maiden flight at Edwards Air Force Base on 22 November 2011.<ref name=DefenseTechNov2011>{{usurped|1=[https://web.archive.org/web/20111130221037/http://defensetech.org/2011/11/28/second-x-47b-uav-flies/#more-15485 "Navy's Second Stealthy X-47B Drone Flies"]}}. DefenseTech.org. 28 November 2011. Retrieved 5 December 2011.</ref>

The two X-47Bs were initially planned to have a three-year test program with 50 tests at Edwards AFB and [[Naval Air Station Patuxent River|NAS Patuxent River, Maryland]], culminating in sea trials in 2013.<ref name=DefenseTechNov2011/><ref>[http://www.as.northropgrumman.com/products/nucasx47b/index.html "X-47B UCAS"] {{webarchive|url=https://web.archive.org/web/20090904091637/http://www.as.northropgrumman.com/products/nucasx47b/index.html |date=4 September 2009 }}. [[Northrop Grumman]]. Retrieved 2 February 2012.</ref> However, they performed so consistently that preliminary tests ended after 16 flights.<ref name=dill>Dillow, Clay. [http://www.popsci.com/technology/article/2012-07/i-am-warplane?page=2 "I Am Warplane"]. ''[[Popular Science]]''. 5 July 2012. Retrieved 1 August 2012.</ref> The Navy decided to have them demonstrate carrier launches and recoveries, as well as autonomous [[Aerial refueling|inflight refueling]] with a [[probe and drogue]]. In November 2011, the Navy announced that aerial refuelling equipment and software would be added to one X-47B in 2014 for testing;<ref>[http://defensesystems.com/articles/2011/11/07/agg-navy-x47b-refueling-capability.aspx?admgarea=DS "Navy to outfit an X-47B prototype with refueling gear".] {{Webarchive|url=https://web.archive.org/web/20160825202258/https://defensesystems.com/articles/2011/11/07/agg-navy-x47b-refueling-capability.aspx?admgarea=DS |date=25 August 2016 }} Defense Systems. 7 November 2011. Retrieved 9 November 2011.</ref> they also affirmed that the demonstrators would never be armed.<ref name=dill/> In 2012, Northrop Grumman tested a wearable [[remote control system]], designed to allow ground crews to steer the X-47B while on the carrier deck.<ref>[http://www.navytimes.com/news/2012/04/navy-next-step-directing-drones-hand-signals-040112w/ "The next step in directing drones: hand signals"]. ''Navy Times''. 1 April 2012. Retrieved 17 April 2012.</ref>

In May 2012, AV-1 began high-intensity [[electromagnetic interference]] testing at Patuxent River, to test compatibility with planned [[electronic warfare]] systems.<ref>[http://www.aviationweek.com/Blogs.aspx?plckBlogId=Blog:27ec4a53-dcc8-42d0-bd3a-01329aef79a7&plckPostId=Blog%3A27ec4a53-dcc8-42d0-bd3a-01329aef79a7Post%3A6f9b3752-2f93-4ba5-9e89-de12fae81857 "Electronic Blast Slated for Unmanned Attack Aircraft"] {{webarchive|url=https://web.archive.org/web/20131220092603/http://www.aviationweek.com/Blogs.aspx?plckBlogId=Blog:27ec4a53-dcc8-42d0-bd3a-01329aef79a7&plckPostId=Blog%3A27ec4a53-dcc8-42d0-bd3a-01329aef79a7Post%3A6f9b3752-2f93-4ba5-9e89-de12fae81857 |date=20 December 2013 }}. ''[[Aviation Week]]''. 3 May 2012. Retrieved 7 May 2012.</ref> In June 2012, AV-2 arrived at Patuxent River to begin a series of tests, including arrested landings and catapult launches, to validate its ability to conduct precision approaches to an aircraft carrier.<ref>[http://www.nbcwashington.com/news/local/Beltway-UFO-has-DC-Talking-159006435.html ""Beltway UFO" has DC Talking"]. NBC Washington. 14 June 2012. Retrieved 14 June 2012.</ref> Its first land-based catapult launch was conducted successfully on 29 November 2012.<ref>{{cite magazine|url=https://www.wired.com/dangerroom/2012/11/navy-killer-drone/|title=Navy Preps Killer Drone for First Carrier Launch|magazine=[[Wired (magazine)|Wired]]|date=30 November 2012|access-date=1 December 2012}}</ref><ref>"X-47B Drone Meets the Fleet". ''Aviation History''. March 2013 issue. p. 10.</ref>

On 26 November 2012, the X-47B began its carrier-based evaluation aboard the {{USS|Harry S. Truman|CVN-75}} at [[Naval Station Norfolk]], Virginia.<ref>{{cite web | author= Taylor DiMartino | title= Truman Hosts X-47B Unmanned Aircraft Demonstrator For Carrier-Based Testing | url= http://www.navy.mil/submit/display.asp?story_id=70457 | work= NNS121126-07 | publisher= USS Harry S. Truman Public Affairs | date= 26 November 2012 | access-date= 7 December 2012 | archive-date= 30 July 2017 | archive-url= https://web.archive.org/web/20170730004741/http://www.navy.mil/submit/display.asp?story_id=70457 | url-status= dead }}</ref> On 18 December 2012, the X-47B completed its first at-sea test phase; it was remarked to have performed "outstandingly", having proved compatible with the [[flight deck]], hangar bays, and communication systems of an aircraft carrier. With deck testing completed, the X-47B returned to NAS Patuxent River for further tests.<ref>[http://www.defense-aerospace.com/article-view/release/141179/x_47b-drone-completes-first-at_sea-tests.html "X-47B Unmanned Combat Air System Completes First At-Sea Tests"] {{Webarchive|url=https://web.archive.org/web/20180411174237/http://www.defense-aerospace.com/article-view/release/141179/x_47b-drone-completes-first-at_sea-tests.html |date=11 April 2018 }}. Defense-Aerospace.com. 18 December 2012. Retrieved 20 December 2012.</ref> On 4 May 2013, it successfully performed an arrested landing on a simulated carrier deck at Patuxent River.<ref>{{cite web |url=http://killerapps.foreignpolicy.com/posts/2013/05/06/video_the_navys_stealth_drone_makes_its_first_arrested_landing |title=Video: The Navy's stealth drone makes its first arrested landing|work=[[Foreign Policy]] |date=6 May 2013 |url-status=dead |archive-url=https://web.archive.org/web/20130509214531/http://killerapps.foreignpolicy.com/posts/2013/05/06/video_the_navys_stealth_drone_makes_its_first_arrested_landing |archive-date=9 May 2013 |df=dmy-all}}</ref> The X-47B launched from the {{USS|George H.W. Bush|CVN-77}} on 14 May 2013 in the [[Atlantic Ocean]], marking the first time that a UAV was [[Steam catapult#Steam catapult|catapulted]] off an aircraft carrier.<ref>{{cite news | title = Navy launches unmanned aircraft from deck of aircraft carrier for 1st time | url = https://www.washingtonpost.com/local/navy-to-attempt-launching-unmanned-aircraft-from-deck-of-aircraft-carrier-for-first-time/2013/05/14/b9387ad2-bc66-11e2-b537-ab47f0325f7c_story.html | newspaper = [[Washington Post]] | agency = [[Associated Press]] | date = 14 May 2013 | access-date = 15 May 2013}}{{dead link|date=June 2021|bot=medic}}{{cbignore|bot=medic}}</ref><ref>{{cite news | title = US launches drone from aircraft carrier for first time | url = https://www.bbc.co.uk/news/world-us-canada-22542663 | work   = [[BBC News Online]] | format = video | date = 15 May 2013 | access-date = 15 May 2013}}</ref> On 17 May 2013, another first was achieved when it performed touch-and-go landings and take-offs from ''George H.W. Bush'' while underway.<ref>{{cite web | author= Mass Communication Specialist 3rd Class Brandon Vinson, USN | title= X-47B Accomplishes First Ever Carrier Touch and Go aboard CVN 77 | url= http://www.navy.mil/submit/display.asp?story_id=74225 | work= NNS130517-15 | publisher= USS George H.W. Bush (CVN-77) Public Affairs | date= 17 May 2013 | access-date= 17 May 2013 | quote= "The Navy's X-47B Unmanned Combat Air System Demonstrator (UCAS-D) has begun touch and go landing operations aboard the aircraft carrier USS ''[[USS George H.W. Bush|George H. W. Bush]]'' (CVN 77) May 17." | archive-date= 4 June 2013 | archive-url= https://web.archive.org/web/20130604155050/http://www.navy.mil/submit/display.asp?story_id=74225 | url-status= dead }}</ref>

On 10 July 2013, the X-47B launched from Patuxent River and landed on the deck of ''George H.W. Bush'', conducting the first ever arrested landing of a UAV on a carrier at sea.<ref name=BBC11July2013>{{cite web |url=https://www.bbc.co.uk/news/23276968|title=US drone lands on aircraft carrier |publisher=BBC New |date=11 July 2013}}</ref> It subsequently completed a second successful arrested landing on ''George H.W. Bush'', but a third attempt was diverted to the [[Wallops Flight Facility]] in Virginia due to a technical issue.<ref>{{cite news |work=[[The Virginian-Pilot]] |title=Glitch forces Navy drone to abort carrier landing |date=12 July 2012 |url=http://hamptonroads.com/2013/07/navy-drone-fails-third-aircraft-carrier-landing-attempt |access-date=12 July 2013 |archive-date=13 July 2013 |archive-url=https://web.archive.org/web/20130713045635/http://hamptonroads.com/2013/07/navy-drone-fails-third-aircraft-carrier-landing-attempt |url-status=dead }}</ref> One of the UAV's three navigational sub-systems failed, which was identified by the other two sub-systems and indicated to the operator, who followed procedures to abort the landing. The Navy stated that the problem's detection demonstrated the X-47B's reliability and ability to operate autonomously.<ref>{{cite news |publisher=National Defense |title=Navy: Glitch in X-47B Test Only Proves Unmanned Aircraft's Reliability |date=11 July 2013 |url=http://www.nationaldefensemagazine.org/blog/Lists/Posts/Post.aspx?ID=1199 |url-status=dead |archive-url=https://web.archive.org/web/20160207020659/http://www.nationaldefensemagazine.org/blog/Lists/Posts/Post.aspx?ID=1199 |archive-date=7 February 2016 |df=dmy-all}}</ref>

On 15 July 2013, the second X-47B, designated 501, was forced to abort another planned landing on ''George H.W. Bush'' due to technical issues.<ref>{{cite web | author= Christopher P. Cavas | title= X-47B Fails Fourth Landing Attempt | url=http://www.navytimes.com/article/20130716/NEWS04/307160019/X-47B-fails-fourth-landing-attempt| work= [[Navy Times]] | publisher= [[Gannett Company]] | date=16 July 2013 | access-date=16 July 2013 |quote="The aircraft developed technical issues while in flight from Naval Air Station Patuxent River, Md., to the ship and officials decided to abort the attempt before the X-47B reached the vicinity of the carrier, steaming off the U.S. east coast."}}</ref><ref name=SoLongFunding/> Officials asserted that the program only required one successful at-sea landing, though testers were aiming for three, while two out of four were achieved.<ref name=SoLongFunding/> The Navy continued flying the two X-47Bs through 2014, after it was criticised for prematurely retiring them.<ref>[http://www.flightglobal.com/news/articles/us-navy-hopes-to-fly-x-47b-demonstrators-into-2014-389216/ "US Navy hopes to fly X-47B demonstrators into 2014"]. Flightglobal.com. 6 August 2013. Retrieved 15 November 2014.</ref> The Navy subsequently deployed the X-47Bs to carriers for three further test phases between 2013 and 2015, with the intent of demonstrating that UAVs could seamlessly work with a 70-plane carrier air wing.<ref>[https://spectrum.ieee.org/x47b-gets-two-more-years-of-tests-to-prep-navy-for-robot-warplanes "X-47B Gets Two More Years of Tests to Prep Navy for Robot Warplanes"]. IEEE Spectrum. 8 August 2013. Retrieved 15 November 2014.</ref>

On 18 September 2013, the X-47B flew the 100th flight for the UCAS-D program. The program objectives were completed in July, which included a total of 16 precision approaches to the carrier flight deck, including five tests of wave-off functions, nine touch-and-go landings, two arrested landings, and three catapult launches.<ref>[http://www.thebaynet.com/news/index.cfm/fa/viewstory/story_ID/33735 "X-47B conducts centennial flight"] {{webarchive|url=https://web.archive.org/web/20130921055608/http://www.thebaynet.com/news/index.cfm/fa/viewstory/story_ID/33735 |date=21 September 2013 }}. Thebaynet.com. 20 September 2013. Retrieved 15 November 2014.</ref> On 10 November 2013, testing continued on board the {{USS|Theodore Roosevelt|CVN-71}}. During this phase, the X-47B's digitized carrier-controlled environment was tested, such as between the UAV and carrier personnel during launching, recovering, and flight operations.<ref>{{cite web | title= X-47B Operates Aboard ''Theodore Roosevelt'' | url= http://www.navy.mil/submit/display.asp?story_id=77580 | work= NNS131110-02 | publisher= USS Theodore Roosevelt Public Affairs | date= 10 November 2013 | access-date= 14 November 2013 | quote= "The X-47B Unmanned Combat Air System Demonstrator (UCAS-D) conducted flight operations aboard the aircraft carrier USS ''Theodore Roosevelt'' (CVN 71), Nov. 10." | archive-date= 15 November 2013 | archive-url= https://web.archive.org/web/20131115005319/http://www.navy.mil/submit/display.asp?story_id=77580 | url-status= dead }}</ref> Trials on ''Theodore Roosevelt'' in 2014 were intended to test the UAV's ability to swiftly take off, land, and hold in a pattern among manned aircraft without disrupting carrier operations. It also used a [[jet-blast deflector]] on deck for the first time, enabling takeoff without impacting operations behind it.<ref>[http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_04_07_2014_p38-676684.xml&p=1 "New X-47B Ship Goal: Clear Deck In 90 Sec."] {{Webarchive|url=https://web.archive.org/web/20140413151538/http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_04_07_2014_p38-676684.xml&p=1 |date=13 April 2014 }}. ''Aviation Week''. 7 April 2014. Retrieved 15 November 2014.</ref>

On 10 April 2014, the X-47B performed its first night flight.<ref>[http://www.flightglobal.com/news/articles/x-47b-conducts-night-flight-named-collier-trophy-winner-398256/ "X-47B conducts night flight, named Collier Trophy winner"]. Flightglobal.com. 15 April 2014. Retrieved 15 November 2014.</ref> On 17 August 2014, it took off and landed on ''Theodore Roosevelt'' alongside an [[F/A-18 Hornet]], marking the first time a UAV operated in conjunction with manned aircraft aboard an aircraft carrier. The Hornet launched from the carrier, followed by the X-47B. After a brief flight, the X-47B touched down and immediately took off again to verify system behavior. After 24 minutes, the X-47B landed on the flight deck and taxied away to give the Hornet room to land. The demonstration met all test objectives, and marked the X-47B's fifth test period at sea, having completed eight catapult launches from a carrier, 30 touch-and-goes, and seven arrested landings aboard ''George H.W. Bush'' and ''Theodore Roosevelt''.<ref>[https://www.dailypress.com/2014/08/17/historic-day-carrier-based-drone-flies-with-manned-aircraft/ "Historic day: Carrier-based drone flies with manned aircraft"]. Dailypress.com. 17 August 2014. Retrieved 15 November 2014.</ref> Testing was successfully completed on 24 August 2014, with the X-47B completing five catapult launches, four arrestments, and nine touch-and-go landings; nighttime taxi and deckhandling operations were also performed for the first time. It met its objective of performing launches and recoveries at 90-second intervals with manned Hornets.<ref>[http://www.navytimes.com/article/20140907/NEWS04/309070024/Unmanned-jet-completes-successful-week-sea "Unmanned jet completes successful week at sea"]. ''Navy Times''. 7 September 2014. Retrieved 15 November 2014.</ref> In April 2015, the X-47B successfully conducted the world's first fully autonomous aerial refuelling with an [[Omega Aerial Refueling Services|Omega Air]] [[KC-707]] tanker over the coast of [[Maryland]].<ref name=EatFuel/><ref>{{cite web|url=http://foxtrotalpha.jalopnik.com/x-47b-demonstrates-unmanned-aerial-refueling-for-the-fi-1698310343|title=X-47B Demonstrates Unmanned Aerial Refueling for the First Time|publisher=Jalopnik.com|date=16 April 2015|access-date=18 April 2015}}</ref> This marked the completion of all primary demonstration tasks required of it.<ref name=Museum/>

In February 2016, the Navy decided to repurpose the X-47B from a surveillance and strike aircraft into a reconnaissance and aerial refuelling drone with "limited strike capability". The change followed a top-level review and restructuring of the now-defunct unmanned carrier-launched airborne surveillance and strike (UCLASS) project, with later budgets instead funding the [[MQ-25 Stingray]] carrier-based aerial refuelling system (CBARS).<ref>{{cite web|url=http://airsoc.com/articles/view/id/56bcf99631394482168b4567/uclass-reborn-as-us-navy-spy-tanker |title=UCLASS REBORN AS US NAVY SPY-TANKER |publisher=airsoc.com. |date= 11 February 2016}}</ref>

===Costs===
The project was initially funded under a US$635.8 million contract awarded by the Navy in 2007. By January 2012, the X-47B's total program cost had grown to an estimated $813 million.<ref name=MoneyMoney>[http://www.latimes.com/business/la-fi-auto-drone-20120126,0,740306.story "New drone has no pilot anywhere, so who's accountable?"] ''[[Los Angeles Times]]''. 26 January 2012. Retrieved 29 January 2012.</ref> Government funding for the X-47B UCAS-D program was to run out at the end of September 2013, with the close of the [[fiscal year]].<ref name=SoLongFunding>{{cite web|url=http://www.militarytimes.com/article/20130716/NEWS04/307160019/X-47B-fails-landing-attempt-again|title=X-47B fails landing attempt - again|work=Military Times|date=16 July 2013|access-date=17 July 2013|archive-date=3 August 2013|archive-url=https://web.archive.org/web/20130803051703/http://www.militarytimes.com/article/20130716/NEWS04/307160019/X-47B-fails-landing-attempt-again|url-status=dead}}</ref> However, in June 2014 the Navy provided an additional $63 million for "post-demonstration" development of the X-47B.<ref>{{cite web|url=http://www.flightglobal.com/news/articles/us-navy-funds-additional-x-47b-development-400840/|title=US Navy funds additional X-47B development|publisher=Flightglobal.com|date=27 June 2014|access-date=15 November 2014}}</ref>

===End of program===
In February 2015, the Navy stated that the competition for private tenders for constructing the UCLASS fleet would begin in 2016, with the aircraft expected to enter service in the early 2020s.<ref name=2023Perhaps/> Reportedly, despite the X-47B's success in test flights, officials were concerned that it would be too costly and insufficiently stealthy for the needs of the UCLASS project.<ref name=2023Perhaps/> In April 2015, it was reported that the X-47B demonstrators would become museum exhibits upon completing flight testing.<ref name=Museum/><ref>{{cite web|url=http://hamptonroads.com/2015/04/scharre-protect-x47b-safeguard-innovation|title=Scharre: Protect the X-47B to safeguard innovation|publisher=HamptonRoads.com|date=25 April 2015|access-date=28 April 2015|archive-date=28 April 2015|archive-url=https://web.archive.org/web/20150428184845/http://hamptonroads.com/2015/04/scharre-protect-x47b-safeguard-innovation|url-status=dead}}</ref> In June 2015, [[United States Secretary of the Navy]] [[Ray Mabus]] stated that the X-47B program should continue but that Northrop-Grumman should not gain an unfair advantage in the competition for the UCLASS contract.<ref>{{cite news|url=http://news.usni.org/2015/06/02/secnav-mabus-x-47b-tests-should-continue-without-giving-uclass-advantage-to-northrop-grumman|title=SECNAV Mabus: X-47B Tests Should Continue Without Giving UCLASS Advantage to Northrop Grumman|newspaper=USNI News|date=2 June 2015|access-date=25 August 2015}}</ref> In July 2015, the Navy stated that the X-47Bs would remain in flying condition rather than being converted to museum exhibits, allowing for a variety of follow-on evaluations.<ref name=Lifeline2015/>

In January 2017, the first X-47B departed NAS Patuxent River, Md. for Northrop Grumman's manufacturing plant in Palmdale, Calif.<ref>{{cite web|url=http://www.navair.navy.mil/index.cfm?fuseaction=home.NAVAIRNewsStory&id=6472|title=NAVAIR News|access-date=15 December 2017|archive-date=15 December 2017|archive-url=https://web.archive.org/web/20171215163744/http://www.navair.navy.mil/index.cfm?fuseaction=home.NAVAIRNewsStory&id=6472|url-status=dead}}</ref> In August 2017, Aviation Week published photos of a modified X-47B as a testbed for Northrop Grumman's [[Boeing MQ-25 Stingray|MQ-25]] bid.
<ref>{{cite web|url=http://aviationweek.com/defense/modified-x-47b-breaks-cover-testbed-mq-25-bid|title = Modified X-47B Breaks Cover as Testbed for MQ-25 Bid &#124; Aviation Week Network}}</ref> On 25 October 2017, the company announced its withdrawal from the MQ-25 competition, saying it would be unable to operate under the terms of the service's request for proposals.<ref>{{cite news|url=https://www.flightglobal.com/news/articles/northrop-grumman-pulls-out-of-mq-25-competition-442510/|title=Northrop Grumman pulls out of MQ-25 competition|work=FlightGlobal|date=25 October 2017|access-date=26 October 2017}}</ref> A modified Deck Handling System demonstration was planned, but efforts were suspended. One X-47B performed a required upkeep static engine run in spring 2019. The other remained stored in a hangar. The older X-47A Pegasus Air Vehicle was also kept in a covered open air hangar at the Palmdale plant, which the general public cannot enter.

==Awards==
In March 2014, the X-47B won the 57th Annual Laureate Award for "extraordinary achievements" in aeronautics and propulsion hosted by ''[[Aviation Week]]''.<ref>[http://www.seapowermagazine.org/stories/20140307-x47b.html "X-47B Program Honored with Laureate Award"]. ''Seapower Magazine''. 7 March 2014. Retrieved 14 November 2014.</ref> On 9 April 2014, the [[National Aeronautic Association]] selected Northrop Grumman, the United States Navy, and the X-47B's development team as the joint recipients of the 2013 [[Collier Trophy]] for excellence in aeronautic technology.<ref>{{cite web|url=http://www.navair.navy.mil/index.cfm?fuseaction=home.PrintNewsStory&id=5596|title=Navy's X-47B program receives aviation honor|publisher=NAVAIR|date=10 April 2014|access-date=15 November 2014|archive-date=26 November 2014|archive-url=https://web.archive.org/web/20141126170647/http://www.navair.navy.mil/index.cfm?fuseaction=home.PrintNewsStory&id=5596|url-status=dead}}</ref>

==Derivative development==
The Navy used software from the X-47B to demonstrate unmanned aerial refueling capabilities. On 28 August 2013, a Calspan-flown [[Learjet 25]] refueled from a [[Boeing 707]] tanker while flying autonomously as a surrogate aircraft uploaded with the X-47B's technology.<ref name=707AutoRe/> The test was to demonstrate that unmanned and optionally manned aircraft can have an automated aerial refueling capability, significantly increasing their range, persistence, and flexibility.<ref name=707AutoRe>{{cite web|url=http://www.flightglobal.com/news/articles/us-navy-begins-unmanned-refuelling-trials-390454/|title=US Navy begins unmanned refuelling trials|publisher=Flightglobal.com|date= 12 September 2013|access-date= 15 November 2014}}</ref> Plans to further demonstrate autonomous aerial refueling were reportedly cut in the Navy's fiscal 2014 budget,<ref>{{cite web|url=http://www.aviationweek.com/Article.aspx?id=/article-xml/asd_04_15_2013_p03-01-568738.xml|title=X-47B Unmanned Aerial Refueling Demo Victim of Cuts|work=Aviation Week|date=15 April 2013|access-date=15 November 2014|archive-date=1 April 2014|archive-url=https://web.archive.org/web/20140401080807/http://www.aviationweek.com/Article.aspx?id=/article-xml/asd_04_15_2013_p03-01-568738.xml|url-status=dead}}</ref> but the X-47B nonetheless conducted a successful autonomous refuelling demonstration in April 2015.<ref name=EatFuel/>

After the USAF made plans for a next generation bomber following the 2006 Quadrennial Defense Review, Northrop Grumman proposed a variety of derivatives based on the X-47B, informally called "X-47C" by the company. One iteration was a bomber to have a [[payload]] of {{convert|10000|lb}} of bombs, significantly exceeding that of the X-47A.<ref>https://www.secretprojects.co.uk/threads/northrop-grumman-rq-180.20900/post-367179 {{Self-published inline|date=July 2024}}</ref><ref name="av">{{Cite web|url=http://aviationweek.com/defense/secret-new-uas-shows-stealth-efficiency-advances|title = Secret New UAS Shows Stealth, Efficiency Advances &#124; Aviation Week Network}}{{clarify|date=May 2023|reason=Paywalled source. Please quote the passage which identifies the subject as the 'X-47C'}}</ref><ref name=":0">{{Cite web |date=2012-03-07 |title=Ultra Stealth {{!}} AVIATION WEEK |url=http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=dti&id=news/DTI-Bomber.xml |access-date=2024-01-06 |archive-url=https://web.archive.org/web/20120307151915/http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=dti&id=news/DTI-Bomber.xml |archive-date=2012-03-07 }}</ref> Although Northrop Grumman estimated that the X-47C could enter service in 2018, the NGB program was shelved in 2010.<ref name="av"/><ref name=":0" />

==Variants==
;[[Northrop Grumman X-47A Pegasus|X-47A]]
Original proof-of-concept prototype with a {{convert|27.8|ft|m|adj=on}} wingspan, first flown in 2003.

;X-47B 
Demonstrator aircraft with a {{convert|62|ft|m|adj=on}} wingspan, first flown in 2011.

;X-47C
Proposed larger version intended for the Navy's [[UCLASS]] project or as an Air Force strategic bomber.

==Specifications (X-47B)==
[[File:Northrop Grumman X-47B 3-view.svg|thumb|200px|Plan diagram of the Northrop Grumman X-47B, with a human to scale]]
{{Aircraft specs
|prime units? = imp
|ref=<ref name="NAVAIR Presentation">{{cite web|url=https://www.slideserve.com/conroy/navy-unmanned-combat-air-system-advanced-development-program-office-navy-ucas-adpo|title=Navy Unmanned Combat Air System Advanced Development Program Office (Navy UCAS ADPO) Program Brief to AUVSI Seafarer Chapter|work=Capt. Rich Brasel|date=23 October 2007|access-date=17 June 2023|archive-date=20 April 2017|archive-url=https://web.archive.org/web/20170420235706/https://www.slideserve.com/conroy/navy-unmanned-combat-air-system-advanced-development-program-office-navy-ucas-adpo}}</ref><ref name="span">{{cite web|url=http://www.theatlanticwire.com/technology/2013/02/future-drone-warfare-is-frightening/61884/|title=The Future of Drone Warfare Is Scary|work=The Atlantic Wire|date=6 February 2013|access-date=7 February 2013|archive-date=11 November 2013|archive-url=https://web.archive.org/web/20131111073443/http://www.theatlanticwire.com/technology/2013/02/future-drone-warfare-is-frightening/61884/|url-status=dead}}</ref><ref name="factsheet">{{cite web | url=http://www.as.northropgrumman.com/products/nucasx47b/assets/UCAS-D_DataSheet_final.pdf | title=X-47 UCAS-D | publisher=Northrop Grumman | date=5 April 2011 |access-date=29 January 2017 | archive-url=https://web.archive.org/web/20100331204427/http://www.as.northropgrumman.com/products/nucasx47b/assets/UCAS-D_DataSheet_final.pdf | archive-date=31 March 2010}}</ref>
|crew=None aboard (semi-autonomous operation)
|length ft= 38.2 
|length m= 11.63 
|span ft= 62.1
|span note= extended; {{cvt|30.9|ft|m}} folded <ref name="span"/>
|height ft= 10.4 
|height m= 3.10 
|wing area sqft= 953.6  
|wing area sqm= 88.59 
|empty weight lb= 28,837 
|empty weight kg= 13,080
|max takeoff weight lb= 44,501 
|max takeoff weight kg= 20,185
|eng1 name= [[Pratt & Whitney F100|Pratt & Whitney F100-220U]]
|eng1 type= turbofan
|eng1 number= 1
|more performance= *'''Cruise speed:''' Mach 0.9+ / 690 mph (high subsonic)<ref>{{cite web|url=http://www.northropgrumman.com/Capabilities/X47BUCAS/Documents/X-47B_Navy_UCAS_FactSheet.pdf|title=Northrop Grumman UCAS-D Datasheet|publisher=Northrop Grumman|date=6 February 2013|access-date=7 February 2013|archive-date=3 February 2019|archive-url=https://web.archive.org/web/20190203103034/http://www.northropgrumman.com/Capabilities/X47BUCAS/Documents/X-47B_Navy_UCAS_FactSheet.pdf|url-status=dead}}</ref><ref>{{cite web|url=http://www.northropgrumman.com/Capabilities/X47BUCAS/Documents/UCAS-D_Data_Sheet.pdf|title=Northrop Grumman UCAS-D Datasheet|publisher=Northrop Grumman|date=6 February 2013|access-date=7 February 2013|archive-date=26 May 2019|archive-url=https://web.archive.org/web/20190526020454/http://www.northropgrumman.com/Capabilities/X47BUCAS/Documents/UCAS-D_Data_Sheet.pdf|url-status=dead}}</ref>
|range nmi= 2,100
|ceiling ft= 42,000 
|ceiling m= 12,800 
|wing loading main= <!-- lb/ft<sup>2</sup> -->
|wing loading alt= <!-- kg/m<sup>2</sup> -->
|armament= *2 weapon bays, providing for up to {{convert|4500|lb|kg|abbr=on}} of ordnance<ref name="factsheet" />
|avionics= *Provisions for EO/IR/SAR/ISAR/GMTI/MMTI/ESM<ref name="factsheet" />
|empty weight note=zero fuel weight <ref name="NAVAIR Presentation" />|max takeoff weight note=<ref name="NAVAIR Presentation" />}}

==See also==
{{aircontent
|related=
* [[Northrop Grumman X-47A Pegasus]]
|similar aircraft=
* [[BAE Taranis]]
* [[Boeing MQ-25 Stingray]]
* [[Boeing X-45]]
* [[CASC CH-7]]
* [[Dassault nEUROn]]
* [[EADS Barracuda]]
* [[General Atomics Avenger]]
* [[Lockheed Martin Polecat]]
* [[McDonnell Douglas X-36]]
* [[Northrop Grumman RQ-180]]
* [[Mikoyan Skat]]
* [[Sukhoi Okhotnik]]
|lists= 
* [[List of experimental aircraft]]
* [[List of tailless aircraft]]
* [[List of UAVs]]
}}

==References==
{{reflist|30em}}

==External links==
{{Commons category|Northrop Grumman X-47B}}
{{ external media
| float=right
| video1 =[https://www.youtube.com/watch?v=HTiRY2ieDN0 Video] of X-47B land [[Aircraft catapult|catapult launch]]
| video2 =[https://www.youtube.com/watch?v=taW3XsZiN2I Video] of X-47B carrier [[Aircraft catapult|catapult launch]]
}}
*[http://www.northropgrumman.com/Capabilities/X47BUCAS/Pages/default.aspx X-47B UCAS page] {{Webarchive|url=https://web.archive.org/web/20150928012156/http://www.northropgrumman.com/Capabilities/x47bucas/Pages/default.aspx |date=28 September 2015 }} and [http://www.northropgrumman.com/MediaResources/Pages/MediaGallery.aspx?ProductId=UC-10028 media gallery on NorthropGrumman.com] {{Webarchive|url=https://web.archive.org/web/20150102164006/http://www.northropgrumman.com/MediaResources/Pages/MediaGallery.aspx?ProductId=UC-10028 |date=2 January 2015 }}
*[https://web.archive.org/web/20090122221737/http://thefutureofthings.com/pod/6239/x-47b-first-navy-stealth-uav-ready.html "X-47B – First Navy Stealth UAV Ready"]. [[The Future of Things]]. 20 January 2009.
*[https://www.wsj.com/articles/SB10001424052702303448404577410032825529656 "Could we trust killer robots?"]. ''[[Wall Street Journal]]''. 19 May 2012.
*[http://www.popsci.com/technology/article/2012-07/i-am-warplane?page=4 "I Am Warplane: How the first autonomous strike plane will land on aircraft carriers, navigate hostile airspace and change the future of flight"]. ''[[Popular Science]]''. 5 July 2012.
*[http://www.bbc.com/future/story/20121218-stealth-drone-targets-life-at-sea "X-47B stealth drone targets new frontiers"]. BBC Future. 19 December 2012.

{{Grumman aircraft}}
{{X-planes}}
{{Stealth aircraft}}

[[Category:Stealth aircraft]]
[[Category:Northrop Grumman aircraft|X-047B]]
[[Category:2010s United States experimental aircraft]]
[[Category:Unmanned military aircraft of the United States]]
[[Category:Single-engined jet aircraft]]
[[Category:Blended wing body]]
[[Category:Tailless aircraft]]
[[Category:Carrier-based aircraft]]
[[Category:Unmanned stealth aircraft]]
[[Category:Scaled Composites]]
[[Category:DARPA]]
[[Category:Edwards Air Force Base]]
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[[Category:Aircraft first flown in 2011]]
[[Category:Aircraft with retractable tricycle landing gear]]