Editing Lockheed S-3 Viking

{{Short description|Carrier-based anti-submarine and aerial refueling aircraft}}
{{Use dmy dates|date=March 2020}}
{{Use American English|date=July 2023}}
{{Infobox aircraft
 |name = S-3 Viking
 |image = File:S-3A (cropped).jpg
 |image_caption = An S-3A Viking from ASW squadron [[VS-37|VS-37 ''Sawbucks'']]
 |aircraft_type= [[Carrier-based aircraft|Carrier-based]] [[maritime patrol aircraft|anti-submarine aircraft]]
 |national_origin= United States
 |manufacturer= [[Lockheed Corporation]]
 |first_flight= 21 January 1972
 |introduction= 20 February 1974
 |retired= 2016 (Navy) <br /> 2021 (NASA)
 |primary_user= [[United States Navy]]
 |more_users= [[NASA]]
 |produced= 1974–1978
 |number_built= 188
 |variants=
}}

The '''Lockheed S-3 Viking''' is a four-crew, [[Twinjet|twin-engine]] [[turbofan]]-powered [[jet aircraft]] designed and produced by the American aerospace manufacturer [[Lockheed Corporation]]. Because of its characteristic sound, it was nicknamed the "War Hoover" after [[The Hoover Company |the vacuum cleaner brand]].

The S-3 was developed in response to the '''VSX''' program conducted by the [[U.S. Navy]] (USN) to procure a successor [[anti-submarine warfare]] (ASW) aircraft to the [[Grumman S-2 Tracker]]. It was designed, with assistance from [[Vought|Ling-Temco-Vought]] (LTV), to be a [[carrier-based aircraft|carrier-based]], subsonic, all-weather, long-range, multi-mission aircraft.

On 21 January 1972, the prototype ''YS-3A'' performed the type's [[maiden flight]]. Upon entering regular service during February 1974, it proved to be a reliable workhorse. In the ASW role, the S-3 carried automated weapons and [[in-flight refueling]] gear. Further variants, such as the ''ES-3A Shadow'' carrier-based [[ELINT|electronic intelligence]] (ELINT) platform, and the ''US-3A'' carrier-based utility and cargo transport, arrived during the 1980s and 1990s. In the late 1990s, the S-3B's mission focus shifted to surface warfare and [[aerial refueling]] a [[carrier battle group]]. It saw combat during the [[Gulf War]] of the early 1990s, the [[Yugoslav Wars]] of the mid-to-late 1990s, and the [[War in Afghanistan]] during the 2000s.

The S-3 was removed from front-line fleet service aboard aircraft carriers in January 2009, its missions having been taken over by the [[Lockheed P-3 Orion|P-3C Orion]], [[Boeing P-8 Poseidon|P-8 Poseidon]], [[Sikorsky SH-60 Seahawk|SH-60 Seahawk]], and [[Boeing F/A-18E/F Super Hornet|F/A-18E/F Super Hornet]]. For more than a decade after that, some S-3s were flown by [[VX-30|Air Test and Evaluation Squadron Thirty]] ([[VX-30]]) at [[Naval Base Ventura County]] / [[NAS Point Mugu]], California, for range clearance and surveillance operations at the NAVAIR Point Mugu Range. These final examples in U.S. Navy service were retired in early 2016. The last operational S-3 was used by the National Aeronautics and Space Administration ([[NASA]]) at its [[Glenn Research Center]] until NASA retired it in mid-2021. Most retired S-3s were placed into storage while options for their future were investigated. During the 2010s, Lockheed Martin proposed to refurbish them for [[carrier onboard delivery]]. The [[Republic of Korea Navy]] also had plans to operate revived S-3s for ASW; these plans were cancelled in 2017.

==Development==
[[File:YS-3A Viking prototype.jpg|alt=|thumb|YS-3A prototype]]
[[File:S-3A escape sys China Lake NAN1-72jpg.jpg|thumb|S-3 escape system testing]]

In the mid-1960s, the [[United States Navy]] (USN) formulated the ''VSX'' (Heavier-than-air, Anti-submarine, Experimental) requirement, which sought a dedicated anti-submarine aircraft capable of flying off of its aircraft carriers as a replacement for its existing inventory of piston-engined [[Grumman S-2 Tracker]]s. The service issued a request for proposals to industry. During August 1968, a team led by Lockheed, as well as a rival team comprising [[Convair]] and [[Grumman]], were requested to further develop their proposals to meet this requirement.<ref name="Frnc Lock p455-6">Francillon 1982, pp. 455–456.</ref>

At this stage, Lockheed recognised that it had little experience in designing carrier based aircraft, thus the company reached out to the industrial conglomerate [[Vought|Ling-Temco-Vought]] (LTV), which joined the team. LTV assumed responsibility for the design of various elements of the airframe, such as the folding wings and tail, the engine nacelles, and the landing gear, some of which had been derived from the earlier [[LTV A-7 Corsair II]] and [[Vought F-8 Crusader]]. [[UNIVAC|Sperry Univac]] Federal Systems was assigned the task of developing the aircraft's onboard computers which integrated input from sensors and [[sonobuoy]]s.<ref name="Fixer p6">Godfrey 1974, p. 6.</ref><ref name="gvg">Goebel, Greg. {{usurped|1=[https://web.archive.org/web/20041231024042/http://www.vectorsite.net/avs3.html "The Lockheed S-3 Viking."]}} ''Air Vectors'', 1 May 2005. Retrieved: 21 April 2010.</ref>

On 4 August 1969, Lockheed's design was selected as the winner of the VSX contest; an order for eight prototypes, designated ''YS-3A'', was promptly received by the company.<ref name="Frnc Lock p457">Francillon 1982, p. 457.</ref><ref name = "desertwarrior 2009"/> On 21 January 1972, the first prototype performed its [[maiden flight]] in the hands of military test pilot [[John Christiansen]].<ref>Francillon 1987, p. 467.</ref><ref name="Fixer p6"/> Flight testing proceeded quickly with no major issues; two years later, the S-3 entered operational service with the U.S. Navy. During the type's production run, which ran from 1974 to 1978, a total of 186 S-3As were constructed.<ref name = "desertwarrior 2009"/> The majority of the surviving S-3As were later upgraded to the improved ''S-3B'' variant, while 16 aircraft were also converted into ''ES-3A Shadow'' [[electronic intelligence]] (ELINT) collection aircraft.

==Design==
The Lockheed S-3 Viking is a conventional [[monoplane]] with a [[cantilever wing|cantilever]] [[shoulder wing]],<ref>Taylor, John W. R.: ''Jane's All The World's Aircraft, 1977–78''. Jane's Yearbooks, London 1977, p. 329.</ref> very slightly swept with a leading edge angle of 15° and an almost straight trailing edge. Its twin [[General Electric TF34/CF34|GE TF-34]] high-bypass [[turbofan]] engines mounted in [[nacelle]]s under the wings provide excellent fuel efficiency, providing the Viking with the required long range and endurance,<ref name="WAPJ34p54-5">Elward 1998, pp. 54–55.</ref> while also maintaining relatively docile engine-out characteristics.<ref name="WAPJ34p69">Elward 1998, p. 69.</ref>

[[File:S-3A MAD DN-SC-87-05743.JPEG|thumb|S-3A with extended MAD-sensor]]
The aircraft can seat four crew members (three officers and one enlisted) with pilot and copilot/tactical coordinator (COTAC) in the front of the cockpit and the tactical coordinator (TACCO) and sensor operator (SENSO) in the back.<ref name = "desertwarrior 2009"/> Entry is via a hatch/ladder folding down out of the lower starboard side of the fuselage behind the cockpit, in between the rear and front seats on the starboard side.<ref name="WAPJ34p54-5"/> When the aircraft's anti-submarine warfare (ASW) role ended in the late 1990s, the enlisted SENSOs were removed from the crew. In tanker crew configuration, the S-3B typically flew with a pilot and co-pilot/COTAC.<ref name=":0">{{cite book |author1 = Petrescu, Dr. Relly Victoria |author2 = Petrescu, Dr. Florian Ion |title = Lockheed Martin |date = 23 December 2012 |publisher=Books on Demand GmbH |location = Norderstedt, Germany |isbn = 978-1481826884 |page = 101}}</ref>{{self-published inline|certain=y|date=May 2023}} The wing is fitted with leading edge and [[Flap (aircraft)|Fowler flaps]]. [[Spoiler (aeronautics)|Spoilers]] are fitted to both the upper and the lower surfaces of the wings. All control surfaces are actuated by dual hydraulically boosted irreversible systems. In the event of dual hydraulic failures, an Emergency Flight Control System (EFCS) permits manual control with greatly increased stick forces and reduced control authority.<ref name="JAWA76p315-6">Taylor 1976, pp. 315–316.</ref>

Unlike many tactical jets which required ground service equipment, the S-3 was equipped with an [[auxiliary power unit]] (APU) and capable of unassisted starts. The aircraft's original APU could provide only minimal electric power and pressurized air for both aircraft cooling and for the engines' pneumatic starters. A newer, more powerful APU could provide full electrical service to the aircraft. The APU itself was started from a hydraulic accumulator by pulling a handle in the cockpit. The APU accumulator was fed from the primary hydraulic system, but could also be pumped up manually (with much effort) from the cockpit.<ref name=":0" />{{self-published inline|certain=y|date=May 2023}}

All crew members sit on forward-facing, upward-firing Douglas Escapac [[zero-zero ejection seat]]s. In "group eject" mode, initiating ejection from either of the front seats ejects the entire crew in sequence, with the back seats ejecting 0.5 seconds before the front in order to provide safe separation (this was to prevent the pilots, who were more aware of what was happening outside the aircraft from ejecting without the rest of the crew, or being forced to delay ejection to order the crew to eject in an emergency; ejection from either rear seat would not eject the pilots, who had to initiate their own ejections, to prevent loss of the aircraft if a rear crewmember ejected prematurely. If a pilot ejected prematurely, the plane was lost anyway, and automatic ejection prevented the crew from crashing with a pilot-less aircraft before they were aware of what had happened). The rear seats are capable of self ejection and the ejection sequence includes a pyrotechnic charge that stows the rear keyboard trays out of the occupants' way immediately before ejection. Safe ejection requires the seats to be weighted in pairs, and when flying with a single crewman in the back the unoccupied seat is fitted with ballast.<ref name=":0" />{{self-published inline|certain=y|date=May 2023}}

At the time it entered the fleet, the S-3 introduced an unprecedented level of systems integration. Previous ASW aircraft like the [[Lockheed P-3 Orion]] and S-3's predecessor, the [[Grumman S-2 Tracker]], featured separate instrumentation and controls for each sensor system. Sensor operators often monitored paper traces, using mechanical calipers to make precise measurements and annotating data by writing on the scrolling paper. Beginning with the S-3, all sensor systems were integrated through a single General Purpose Digital Computer (GPDC). Each crew station had its own display, the co-pilot/COTAC, TACCO and SENSO displays were Multi-Purpose Displays (MPD) capable of displaying data from any of a number of systems. This new level of integration allowed the crew to consult with each other by examining the same data at multiple stations simultaneously, to manage workload by assigning responsibility for a given sensor from one station to another and to easily combine clues from each sensor to classify faint targets. As a consequence of this integration, the four-crew S-3 was considered roughly equivalent in terms of capability to the much larger P-3, operated by a crew of 12.{{Citation needed|date=May 2022}}

The aircraft has two underwing hardpoints that can be used to carry fuel tanks, general purpose and cluster bombs, missiles, rockets, and storage pods.<ref name = "desertwarrior 2009"/> It also has four internal bomb bay stations that can be used to carry general-purpose bombs, [[aerial torpedo]]es, and special stores (B57 and B61 nuclear weapons). Fifty-nine [[sonobuoy]]s are carried, as well as a dedicated Search and Rescue (SAR) chute. The S-3 is fitted with the ALE-39 countermeasure system and can carry up to 90 rounds of [[Chaff (radar countermeasure)|chaff]], [[flare]]s, and expendable jammers (or a combination of all) in three dispensers. A retractable [[magnetic anomaly detector]] (MAD) Boom is fitted in the tail.<ref name = "desertwarrior 2009"/>

In the late 1990s, the S-3B's role was changed from anti-submarine warfare (ASW) to anti-surface warfare (ASuW). As a consequence of this role change, the MAD Boom was removed, along with several hundred pounds of submarine detection electronics. As there was no remaining sonobuoy processing capability, most of the sonobuoy chutes were faired over with a blanking plate.{{Citation needed|date=May 2022}}

==Operational history==
[[File:S-2G and S-3A in flight 1976.jpg|thumb|S-3A replaced the outdated [[S-2 Tracker]] in 1975]]

On 20 February 1974, the S-3A officially became operational with the [[VS-41|Air Antisubmarine Squadron FORTY-ONE (VS-41)]], the "Shamrocks," at [[NAS North Island]], California, which served as the initial S-3 Fleet Replacement Squadron (FRS) for both the Atlantic and Pacific Fleets until a separate Atlantic Fleet FRS, VS-27, was established in the 1980s. The first operational cruise of the S-3A took place in 1975 with the [[Sea Control Squadron 21|VS-21]] "Fighting Redtails" aboard {{USS|John F. Kennedy|CV-67|6}}.<ref name=":0" />{{self-published inline|certain=y|date=May 2023}}

Initial operations of the Viking were somewhat troubled in the carrier environment, its sophisticated mission systems were largely dependent on the mission computer, which would often "dump" during the stress of a catapult-assisted take-off, requiring the crew to restart it and reload the software.<ref name = "desertwarrior 2009"/> The U.S. Navy had also purchased an insufficient number of spare parts, which negatively impacted the aircraft's mission readiness. Performance improved considerably once an ample supply of spares was provisioned, allowing the S-3 to become a valuable ASW asset as well as a good surface-surveillance platform.<ref name = "desertwarrior 2009">{{cite web |url = https://www.thefreelibrary.com/S-3+Viking%3A+from+sub+hunter+to+desert+warrior.-a0230156116 |title = S-3 Viking: from sub hunter to desert warrior |publisher = Naval Aviation News |first = Rick |last = Burgess |date = 1 November 2009}}</ref>

Starting in 1987, the majority of S-3As were progressively upgraded to the improved ''S-3B'' standard; this involved the addition of several new sensors, avionics, and weapons systems, which included the capability to launch the [[AGM-84 Harpoon]] [[anti-ship missile]].<ref name = "nasaretire ain"/><ref name = "desertwarrior 2009"/> The S-3B could also be fitted with "[[buddy store]]s", external fuel tanks that allowed the Viking to refuel other aircraft. During July 1988, VS-30 became the first fleet squadron to receive the enhanced capability Harpoon/ISAR equipped S-3B, based at [[Naval Air Station Cecil Field|NAS Cecil Field]] in [[Jacksonville, Florida]].

Additional, often more specialised variants, were also produced. 16 S-3As were converted to ''ES-3A Shadow''s for carrier-based [[ELINT|electronic intelligence]] (ELINT) duties. Six aircraft, designated ''US-3A'', were converted for a specialized utility and limited cargo [[Carrier onboard delivery]] (COD) requirement.<ref name = "nasaretire ain"/> This model played a key role in US military efforts to relieve the [[Iran hostage crisis]] of 1979–1981.<ref name = "desertwarrior 2009"/> Plans were also made to develop the ''KS-3A'' carrier-based [[Tanker (aircraft)|tanker]] aircraft, but this program was ultimately cancelled after the conversion of just one early development S-3A.<ref name="ai786 p44-5">''Air International'' July 1986, pp. 44–45.</ref>

As a consequence of the collapse of the [[Soviet Union]] and the breakup of the [[Warsaw Pact]] in the early 1990s, the Soviet-Russian submarine threat was perceived as much reduced, and the Vikings had the majority of their [[antisubmarine warfare]] equipment removed. The aircraft's mission subsequently changed to sea surface search, sea and ground attack, over-the-horizon targeting, and aircraft refueling.<ref name="gvg" /><ref name = "nasaretire ain"/> As a result, the S-3B after 1997 was typically crewed by a single pilot along with a copilot [NFO]; the additional seats remained in place in the S-3B and could be used by additional crew members for certain missions. To reflect these new missions, the Viking squadrons were redesignated from "Air Antisubmarine Warfare Squadrons" to "Sea Control Squadrons".<ref name = "desertwarrior 2009"/>

[[File:S-3A VS-32 1982.JPEG|thumb|VS-32 S-3A: During the [[Cold War]], the S-3's main task was [[anti-submarine warfare]]]]
Prior to the aircraft's retirement from front-line fleet use aboard US aircraft carriers, a number of upgrade programs were implemented. These include the Carrier Airborne Inertial Navigation System II (CAINS II) upgrade, which replaced older [[inertial navigation]] hardware with [[ring laser gyroscope]]s with a Honeywell EGI (Enhanced [[GPS]] Inertial Navigation System) and added digital electronic flight instruments (EFI). The Maverick Plus System (MPS) added the capability to employ the [[AGM-65 Maverick|AGM-65E]] laser-guided or AGM-65F infrared-guided air-to-surface missile, and the [[Standoff Land Attack Missile|AGM-84H/K Stand-off Land Attack Missile Expanded Response]] (SLAM/ER). The SLAM/ER is a GPS/inertial/infrared guided cruise missile derived from the AGM-84 Harpoon that can be controlled by the aircrew in the terminal phase of flight if an AWW-13 data link pod is carried by the aircraft.<ref name="gvg" />

The S-3B saw extensive service during the 1991 [[Gulf War]], performing attack, tanker, and ELINT duties, and launching [[ADM-141 TALD]] decoys. One such aircraft, launched from the aircraft carrier {{USS|Theodore Roosevelt|CVN-71}}, was responsible for the destruction of an Iraqi [[Silkworm missile|Silkworm]] anti-ship missile site, having fired AGM-84 SLAM missiles at it.<ref name = "national 2020">{{cite web |url = https://nationalinterest.org/blog/reboot/submarine-killer-why-did-us-navy-retire-its-vaunted-s-3-viking-planes-172905 |title = Submarine Killer: Why Did the U.S. Navy Retire Its Vaunted S-3 Viking Planes? |publisher = nationalinterest.org |first = Sebastien |last = Roblin |date = 19 November 2020}}</ref> It was commonly deployed to hunt for [[Scud missile]] launcher. The Vikings also identified and targeted numerous Iraqi naval vessels, and even destroyed anti-aircraft gun emplacements and coastal radars.<ref name = "national 2020"/><ref name = "desertwarrior 2009"/> The Gulf War was the first event in which the type had been employed overland in offensive air strike capacity.{{Citation needed|date=May 2022}}

The Viking also participated in the [[Yugoslav wars]] in the 1990s, and in [[Operation Enduring Freedom]] in the 2000s. For the latter, the opening phase of the [[War in Afghanistan (2001–2021)|War in Afghanistan]] in October 2001, many Vikings were deployed as tankers to continuously undertake refueling sorties to support various fighters stationed aboard U.S. carriers, giving them the necessary endurance to fly to and from the conflict zone.<ref name = "national 2020"/><ref name = "desertwarrior 2009"/>

===Electronic surveillance===
The first ES-3A was delivered during 1991 and entered front-line service after two years of testing. The U.S. Navy established two squadrons, each equipped with eight ES-3As, stationed in both the Atlantic and Pacific Fleets to provide detachments of typically two aircraft, ten officers, and 55 enlisted aircrew, maintenance and support personnel (which comprised/supported four complete aircrews) to deploying carrier air wings. The Pacific Fleet squadron, [[VQ-5|Fleet Air Reconnaissance Squadron FIVE (VQ-5)]], the "Sea Shadows," was originally based at the former [[Antonio B. Won Pat International Airport|NAS Agana]], Guam but later relocated to [[Naval Air Station North Island|NAS North Island]] in [[San Diego, California]], with the Pacific Fleet S-3 Viking squadrons when NAS Agana closed in 1995 as a result of a 1993 [[Base Realignment and Closure]] (BRAC) decision. The Atlantic Fleet squadron, the [[VQ-6|VQ-6 "Black Ravens]]," were originally based with all Atlantic Fleet S-3 Vikings at the former NAS Cecil Field in Jacksonville, Florida, but later moved to [[Naval Air Station Jacksonville|NAS Jacksonville]], approximately {{convert|10|mi|km}} to the east, when NAS Cecil Field was closed in 1999 as a result of the same 1993 BRAC decision that closed NAS Agana.{{Citation needed|date=May 2022}}

[[File:S-3 Viking in-flight refueling.jpg|thumb|After the [[Grumman A-6 Intruder#KA-6D|KA-6D]] retirement the S-3B became the main aerial refueling aircraft]]
The ES-3A operated primarily with [[carrier battle group]]s, providing organic 'Indications and Warning' support to the group and joint theater commanders. In addition to their warning and reconnaissance roles, and their extraordinarily stable handling characteristics and range, Shadows were a preferred recovery tanker (aircraft that provide refueling for returning aircraft). They were also deployed to active combat zones, seeing use over [[Yugoslavia]] to identify targets, as well as to enforce the [[no-fly zone]] over Iraq.<ref name = "national 2020"/> The Shadows reportedly averaged over 100 flight hours per month while deployed. Excessive utilization caused earlier than expected equipment replacement when Naval aviation funds were limited, making them an easy target for budget-driven decision makers. The type was also deemed by some officials to be too costly to continue operating.<ref name = "desertwarrior 2009"/> In 1999, both ES-3A squadrons and all 16 aircraft were decommissioned and the ES-3A inventory placed in [[Aerospace Maintenance and Regeneration Group]] (AMARG) storage at [[Davis-Monthan AFB]], Arizona.{{Citation needed|date=May 2022}}

===Iraq War===
The S-3 was an active participant in [[Operation Iraqi Freedom]], the US invasion of Iraq; it largely performed intelligence and reconnaissance missions in support of other coalition assets.<ref name = "desertwarrior 2009"/> On one occasion, in March 2003 a single S-3B Viking from Sea Control Squadron 38 (The "Red Griffins"), piloted by Richard McGrath Jr., from the aircraft carrier {{USS|Constellation|CV-64}} successfully executed a time-sensitive strike, firing a laser-guided Maverick missile that neutralized a significant Iraqi naval and leadership target in the port city of [[Basra]], [[Iraq]].<ref name = "national 2020"/> This was the first time an S-3 launched a laser-guided [[Maverick missile]] in combat.<ref name = "desertwarrior 2009"/> As the conflict progressed, S-3s were regularly used as surveillance aircraft, often to identify [[improvised explosive device]]s (IEDs) and the insurgents who planted them.<ref name = "desertwarrior 2009"/>

[[File:Navy One.jpg|thumb|S-3B Viking "Navy One" on {{USS|Abraham Lincoln|CVN-72|6}}, May 2003]]
On 1 May 2003, US President [[George W. Bush]] flew in the co-pilot seat of a [[VS-35 (1990-2005)|VS-35]] Viking from [[NAS North Island]], California, to the aircraft carrier {{USS|Abraham Lincoln|CVN-72|6}} off the California coast; while the carrier was well within range of helicopters, it is believed that the S-3 was used as a means of setting a desired tone.<ref name = "national 2020"/> Aboard the carrier, he delivered his "[[Mission Accomplished speech|Mission Accomplished]]" speech announcing the end of major combat in the [[2003 invasion of Iraq]].<ref name = "national 2020"/> During the flight, the aircraft used the presidential [[callsign]] of "[[Navy One]]". The aircraft that President Bush flew in was retired shortly thereafter and on 15 July 2003 was accepted as an exhibit at the [[National Museum of Naval Aviation]] at [[NAS Pensacola]], Florida.

Between July and December 2008, the [[VS-22]] Checkmates, the last sea control squadron, operated a detachment of four S-3Bs from the [[Al Asad Airbase]] in [[Al Anbar Governorate|Al Anbar Province]], {{convert|180|mi|km}} west of Baghdad. The planes were fitted with [[LANTIRN]] pods and they performed non-traditional intelligence, surveillance, and reconnaissance.<ref name = "national 2020"/> After more than 350 missions, the Checkmates returned to NAS Jacksonville, Florida, on 15 December 2008. The squadron was disestablished on 29 January 2009.<ref name=DID>{{cite news |title = The Final Boat: End of the USN's S-3B Vikings |url = http://www.defenseindustrydaily.com/89m-for-fy-2007-support-of-the-usns-s3b-vikings-02777/ |work = Defense Industry Daily |date = 2 February 2009 |access-date = 3 February 2009 }}</ref>

===Final years and retirement===
[[File:S-3B VX-30 at NAS Jax 2010.jpg|thumb|[[VX-30]]'s S-3B, callsign "Bloodhound 700", in 2010.]]
[[File:NASA Glenn Research Center S-3B.jpg|thumb|S-3B N601NA was operated by [[NASA]] from 2009 to 2021.]]

A proposed airframe known as the [[Common Support Aircraft]] was advanced as a successor to the S-3, [[Northrop Grumman E-2 Hawkeye|E-2]], and [[Grumman C-2 Greyhound|C-2]], but this initiative failed to materialize. In 1998, the U.S. Navy awarded a $40 million contract for Lockheed Martin to perform a full-scale [[Fatigue testing]] of the existing S-3s; these tests, which commenced in June 2001, were aimed at extending the viable service life of each remaining aircraft, which had originally been certified for a structural life of 13,000 flight-hours. It was hoped that this could be extended to as much as 17,750 hours.<ref>{{cite web |url = https://news.lockheedmartin.com/2001-06-28-Lockheed-Martin-Aeronautics-Begins-S-3-Viking-Full-Scale-Fatigue-Testing |title = Lockheed Martin Aeronautics Begins S-3 Viking Full Scale Fatigue Testing |publisher = Lockheed Martins |date = 28 June 2001}}</ref>

The final carrier-based S-3B squadron, VS-22, was decommissioned at NAS Jacksonville on 29 January 2009. Sea Control Wing Atlantic was decommissioned the following day, along with the last S-3s in frontline fleet service.<ref name="Navy Retires S-3B">{{cite web |url = http://www.lockheedmartin.com/news/press_releases/2009/090130ae_s3b-viking-retirement.html |title = U.S. Navy retires last Lockheed Martin S-3B Viking from fleet service |publisher = Lockheed Martin |date = 30 January 2009 |access-date = 21 April 2010 |archive-date = 2 June 2009 |archive-url = https://web.archive.org/web/20090602055342/http://www.lockheedmartin.com/news/press_releases/2009/090130ae_s3b-viking-retirement.html |url-status = dead }} {{Cite web |url=http://www.lockheedmartin.com/news/press_releases/2009/090130ae_s3b-viking-retirement.html |title=U.S. Navy Retires Last Lockheed Martin S-3B Viking from Fleet Service; Carrier-Based Multi-Mission Aircraft Completes 35-Year Career &#124; Lockheed Martin |access-date=5 February 2009 |archive-date=2 June 2009 |archive-url=https://web.archive.org/web/20090602055342/http://www.lockheedmartin.com/news/press_releases/2009/090130ae_s3b-viking-retirement.html |url-status=dead }}</ref><ref name = "desertwarrior 2009"/>

In June 2010, the first of three S-3s to patrol the [[Pacific Missile Test Center]]'s range areas off of California was reactivated and delivered. The jet aircraft's higher speed, ten-hour endurance, modern radar, and a LANTIRN targeting pod allowed it to quickly confirm the test range being clear of wayward ships and aircraft before tests commence.<ref name="S-3B re-enters service at test range">{{cite web |url = http://www.janes.com/news/defence/idr/idr100603_1_n.shtml |title = S-3B Viking re-enters USN service in test range surveillance role |publisher = IHS Jane's |date = 3 June 2010 |access-date = 8 June 2010}}</ref> These S-3Bs are flown by Air Test and Evaluation Squadron Thirty ([[VX-30]]) based out of [[NAS Point Mugu]], California.<ref>{{cite web |url = http://www.navair.navy.mil/index.cfm?fuseaction=home.NAVAIRNewsStory&id=4604 |title = Last S-3B Viking overhauled at FRCSE heads for California-based test squadron |publisher = Naval Air Systems Command (United States Navy) |date = 3 June 2011 |access-date = 23 April 2013 |archive-date = 26 September 2012 |archive-url = https://web.archive.org/web/20120926080000/http://www.navair.navy.mil/index.cfm?fuseaction=home.NAVAIRNewsStory&id=4604 |url-status = dead }}</ref><ref>{{cite web |url = http://www.janes.com/news/defence/idr/idr100603_1_n.shtml |title = S-3B Viking re-enters USN service in test range surveillance role |publisher = Janes.com |access-date = 13 March 2015}}</ref> By late 2015, the U.S. Navy were operating a total of three Vikings in support roles. One was relocated to [[Davis–Monthan Air Force Base|The Boneyard]] in November 2015, while the final two were retired, one being stored and the other transferred to [[NASA]], on 11 January 2016, officially retiring the S-3 from Navy service.<ref name="flightglobal14jan16">{{cite web |url = https://www.flightglobal.com/news/articles/us-navy-retires-its-last-s-3b-vikings-420816/ |title = US Navy retires its last S-3B Vikings |publisher = Flightglobal.com |date = 14 January 2016}}</ref><ref name=Navy_retire>{{cite web |url = http://theaviationist.com/2016/01/14/u-s-navy-bids-farewell-to-the-s-3-viking/ |title = U.S. Navy bids farewell to the S-3 Viking |publisher = theaviationist.com |date = 14 January 2016}}</ref>

During 2004, NASA acquired four of the withdrawn S-3Bs for use at its [[Glenn Research Center]].<ref name = "nasaretire ain">{{cite web |url = https://www.ainonline.com/aviation-news/defense/2021-07-15/nasa-retires-last-flying-s-3-viking |title = NASA Retires Last Flying S-3 Viking |publisher = [[AINonline]] |first = David |last = Donald |date = 14 July 2021}}</ref> In 2009, one of these aircraft (USN BuNo 160607) was given the civil registration ''N601NA'', it was involved in numerous tests conducted by the agency. For over a decade, this aircraft was flying almost every day in support for various research programs;<ref name = "nasaretire ain"/> one such initiative was the definition of new [[Federal Aviation Administration]] communication standards for [[unmanned aerial vehicle]]s operating in US airspace.<ref>{{cite web |url = https://www.ainonline.com/aviation-news/2013-07-05/nasa-tests-prototype-uas-datalink-radio |title = NASA Tests Prototype UAS Datalink Radio |publisher = AINonline |first = Bill |last = Carey |date = 5 July 2013}}</ref> However, a lack of spare parts and increasing difficulty supporting the type meant their use could not continue in the long term. The last of the NASA's S-3Bs, which were the final working members of the type in existence with any operator at that point, were retired on 13 July 2021.<ref>{{cite web |url = https://www.nasa.gov/feature/glenn/2021/NASA-retires-S-3B-Viking-research-aircraft-from-its-fleet/ |title = NASA Retires a Research Workhorse |publisher = NASA |date = 8 July 2021 |access-date = 12 July 2021}}</ref><ref name = "nasaretire ain"/>

Naval analysts have suggested that the U.S. Navy return to service an unspecified quantity of the stored S-3s in order to fill gaps that were left in the carrier air wing when it was retired. This move was promoted as a response to the realization that the [[People's Liberation Army Navy|Chinese navy]] is producing increasingly capable weapons that can threaten carriers beyond the range their aircraft can strike them. Against the [[DF-21#DF-21D (CSS-5 Mod-4) Anti-ship ballistic missile|DF-21D]] [[anti-ship ballistic missile]], carrier-based [[F/A-18 Super Hornet]]s and [[F-35C Lightning II]]s have about half the unrefueled strike range, so bringing the S-3 back to aerial tanking duties would extend their range against it, as well as free up Super Hornets forced into tanking. Against submarines armed with anti-ship cruise missiles like the [[Klub missile|Klub]] and [[YJ-18]], the S-3 would restore area coverage for ASW duties. Bringing the S-3 out of retirement could at least be a stop-gap measure to increase the survivability and capabilities of aircraft carriers until new aircraft can be developed for such purposes.<ref>{{cite web |url = https://thediplomat.com/2015/11/u-s-navy-time-to-bring-back-the-s-3-viking/ |title = U.S. Navy: Time to Bring Back the S-3 Viking? |publisher = Thediplomat.com |date = 9 November 2015}}</ref>

===Potential revival and proposals===
In October 2013, the [[Republic of Korea Navy]] expressed its interest in acquiring up to 18 ex-USN S-3s to augment their fleet of 16 Lockheed P-3 Orion aircraft.<ref>Sung-Ki, Jung [http://archive.defensenews.com/article/20131026/DEFREG03/310260005/S-Korea-Envisions-Light-Aircraft-Carrier "S. Korea envisions light aircraft carrier."] {{webarchive|url=https://archive.today/20150315034643/http://archive.defensenews.com/article/20131026/DEFREG03/310260005/S-Korea-Envisions-Light-Aircraft-Carrier |date=15 March 2015 }} ''Defense News'', 26 October 2013. Retrieved: 13 March 2015.</ref> In August 2015, a military program review group approved a proposal to incorporate 12 mothballed S-3s to perform ASW duties; the Viking plan was sent onto the [[Defense Acquisition Program Administration]] for further assessment before final approval decision by the national defense system committee. Although the planes are relatively old, being in storage has supposedly kept them serviceable, and using them is an affordable means of fulfilling short-range airborne ASW capabilities that were vacated by the retirement of the S-2 Tracker.<ref>{{cite web |url = http://english.yonhapnews.co.kr/national/2015/09/06/0301000000AEN20150906002600320.html |title = S. Korea moving ahead to introduce Viking anti-submarine planes into service |publisher = Yonhapnews.co.kr |date = 9 September 2015}}</ref> Refurbished S-3s could have been returned to use by 2019.<ref name="flightglobal14jan16"/> In 2017, the Republic of Korea Navy canceled plans to purchase refurbished and upgraded Lockheed S-3 Viking aircraft for maritime patrol and anti-submarine duties, leaving offers by Airbus, Boeing, Lockheed Martin, and Saab on the table.<ref>{{cite web |last1 = Perrett |first1 = Bradley |last2 = Kim |first2 = Minseok |title = S. Korea Eyeing P-8, Swordfish As S-3 Upgrade Dropped|url=http://aviationweek.com/awindefense/s-korea-eyeing-p-8-swordfish-s-3-upgrade-dropped |website = Aviation Week |access-date = 19 October 2017 |archive-url = https://archive.today/20171019084626/http://aviationweek.com/awindefense/s-korea-eyeing-p-8-swordfish-s-3-upgrade-dropped |archive-date = 19 October 2017 |location = Melbourne, Australia and Seoul |date = 16 March 2017 |url-status = dead}}</ref><ref>{{cite web |last1 = Waldron |first1 = Greg |title = ADEX: Big MPAs hunt for Seoul maritime requirement |url = https://www.flightglobal.com/news/articles/adex-big-mpas-hunt-for-seoul-maritime-requirement-442267/ |website = FlightGlobal |access-date = 19 October 2017 |archive-url = https://archive.today/20171019084538/https://www.flightglobal.com/news/articles/adex-big-mpas-hunt-for-seoul-maritime-requirement-442267/ |archive-date = 19 October 2017 |location = Seoul |date = 18 October 2017 |url-status = dead}}</ref>

During April 2014, Lockheed Martin announced that they would offer refurbished and remanufactured S-3s, dubbed the ''C-3'', as a replacement for the Northrop [[Grumman C-2A Greyhound]] for [[carrier onboard delivery]]. The requirement for 35 aircraft would be met from the 91 S-3s currently in storage.<ref>{{cite web |last = Cavas |first = Christopher P. |url = http://www.defensenews.com/article/20140409/DEFREG02/304090028/ |title = Lockheed revives an old idea for new carrier cargo plane |publisher = Defense News |date = 9 April 2014 |archive-url=https://archive.today/20150209193642/http://www.defensenews.com/article/20140409/DEFREG02/304090028/ |archive-date=9 February 2015 |url-status=dead}}</ref> In February 2015, the Navy announced that the [[Bell Boeing V-22 Osprey]] had been selected to replace the C-2 for the COD mission.<ref>{{cite web |last = Kreisher |first = Otto |url = http://breakingdefense.com/2015/02/navy-2016-budget-funds-v-22-cod-buy-carrier-refuel/ |title = Navy 2016 budget funds V-22 COD buy, carrier refuel |publisher = Breaking Defense |date = 2 February 2015}}</ref><ref>{{Cite web |url = http://news.usni.org/2015/01/13/navy-selects-bell-boeing-osprey-next-carrier-delivery-aircraft |title = Navy and Marines Sign MOU for Bell-Boeing Osprey to be Next Carrier Delivery Aircraft |publisher = News.USNI.org |date = 13 January 2015}} {{Cite web |url=http://news.usni.org/2015/01/13/navy-selects-bell-boeing-osprey-next-carrier-delivery-aircraft |title=Updated: Navy and Marines Sign MOU for Bell-Boeing Osprey to be Next Carrier Delivery Aircraft |date=13 January 2015 |access-date=23 May 2022 |archive-date=18 January 2015 |archive-url=https://web.archive.org/web/20150118201328/http://news.usni.org/2015/01/13/navy-selects-bell-boeing-osprey-next-carrier-delivery-aircraft |url-status=live}}</ref> A SV-22 was a proposed [[anti-submarine warfare]] variant the U.S. Navy studied in the 1980s to replace S-3 Viking and late model [[Kaman SH-2 Seasprite|SH-2 Seasprite]] ASW helicopters.<ref name="Norton_p28_48">Norton 2004, pp. 28–30, 35, 48.</ref>

==Variants==
[[File:US-3A DN-SC-87-06468.JPEG|thumb|US-3A of [[VRC-50]] in 1987]]
[[File:ES-3As in flight.jpg|thumb|ES-3As of VQ-5]]
[[File:Lockheed S-3B Viking of VS-35 in flight on 23 January 1995 (6655041).jpg|thumb|S-3B with D-704 [[buddy store]]]]
[[File:ES-3A Shadow VQ-6 in flight off Florida.jpg|thumb|ES-3A Shadow of [[VQ-6]]]]

;S-3A
:First production version, 187 built.<ref name="JanesUp94 p334-5">Michell 1994, pp. 334–335.</ref><ref name="WAPJ34p53">Elward 1998, p. 53.</ref>
;S-3B
:Upgraded avionics, AN/APS-137 [[inverse synthetic aperture radar]], [[Joint Tactical Information Distribution System]], [[AGM-84 Harpoon]] launch capability, first flight 13 September 1984, 119 converted from S-3As.
;ES-3A Shadow
:Designed as a carrier-based, subsonic, all-weather, long-range, electronic reconnaissance ([[ELINT]]) aircraft. 16 aircraft were modified to replace the [[Douglas A-3 Skywarrior|EA-3B Skywarrior]], entering fleet service in 1993. The ES-3A carried an extensive suite of electronic sensors and communications gear, replacing the S-3's [[magnetic anomaly detector|submarine detection]], armament, and maritime surveillance equipment with avionics racks accommodating the ES-3A's sensors. These modifications had minor impact on [[airspeed]], reducing its top rated speed from {{convert|450|to|405|kn|km/h}} but had no noticeable impact on the aircraft's [[range (aircraft)|range]] and actually increased its rated loiter time. Because these aircraft were standoff indications and warnings platforms and were never intended to be part of an ingress strike package, this new speed limitation was considered insignificant.{{Citation needed|date=May 2022}}
;KS-3A
:Proposed dedicated air tanker with fuel capacity of 4,382&nbsp;US gal (16,600&nbsp;L), one converted from YS-3A, later converted to US-3A.<ref name="ai786 p44-5"/>
;KS-3B
:Proposed air tanker based on S-3B and utilizing the buddy refueling system, not built.
;US-3A
:S-3A modified for [[carrier onboard delivery]], capacity for six passengers or {{convert|4,680|lb|kg}} of cargo, retired in 1998.
;Aladdin Viking
:Conversion of six aircraft for overland surveillance and Elint missions. May have dropped ground sensors in the [[Bosnian War]].
;Beartrap Viking
:S-3Bs fitted with still-classified modifications.
;Calypso Viking
:Proposed anti-[[smuggling]] variant, not built.
;Gray Wolf Viking
:One aircraft fitted with [[AN/APG-76 radar]] in a modified cargo pod under the wing. Also dubbed '''SeaSTARS''' in reference to [[E-8 Joint STARS]].
;Orca Viking
:Avionics testbed.
;Outlaw Viking
:One S-3B fitted with [[Over-the-horizon Airborne Sensor Information System]] (OASIS III), returned to regular S-3B in 1998. This particular Viking is now on display at the [[USS Midway Museum|USS ''Midway'' Museum]], located on the decommissioned {{USS|Midway|CV-41}}.{{citation needed|date=December 2022}}[[File:Lockheed S-3 Viking Variants.png|alt=Variants of the S-3 Viking.|thumb|363x363px|Main Variants of the S-3 Viking.]]
;NASA Viking
:One aircraft was extensively rebuilt into a state-of-the-art NASA research aircraft. The Navy's Fleet Readiness Center Southeast and a Boeing facility in Florida modified it, adding commercial satellite communications, global positioning navigation, and weather radar systems. They also installed research equipment racks in what was once the plane's bomb bay. NASA's S-3B Viking was equipped to conduct science and aeronautics missions, such as environmental monitoring, satellite communications testing, and aviation safety research.<ref>{{cite web |last = Wittry |first = Jan |url = http://www.nasa.gov/topics/aeronautics/features/s3_viking.html |title = Military Aircraft to Perform Aviation Safety Research |publisher = NASA's Glenn Research Center |date = 2 August 2008 |access-date = 21 April 2010 |archive-date = 24 November 2010 |archive-url = https://web.archive.org/web/20101124135604/http://www.nasa.gov/topics/aeronautics/features/s3_viking.html |url-status = dead }}</ref>

==Operators==
;{{USA}}
* [[United States Navy]] (former)
** [[Sea Control Squadron 21|VS-21 Red Tails]] (1975-2005)<ref>{{Cite web |title=VS-21 |url=http://gonavy.jp/navy/sqn/VS21.html |access-date=2022-09-02 |website=gonavy.jp}}</ref>{{unreliable source?|date=September 2022}}
** [[VS-22|VS-22 Checkmates]] (1976-2009)<ref>{{Cite web |title=VS-22(1960-2009) |url=http://gonavy.jp/navy/sqn/VS22b.html |access-date=2022-09-02 |website=gonavy.jp}}</ref>{{unreliable source?|date=September 2022}}
** [[VS-24|VS-24 Scouts]] (1977-2007)<ref>{{Cite web |title=VS-24(1960-2007) |url=http://gonavy.jp/navy/sqn/VS24b.html |access-date=2022-09-02 |website=gonavy.jp}}</ref>{{unreliable source?|date=September 2022}}
** VS-27 Seawolves/Grim Watchdogs (1987-1994)<ref>{{Cite web |title=VS-27 |url=http://www.wings-aviation.ch/25-Navy-Sqn/VS-Squadrons/27/VS-27-second.htm |access-date=2022-09-02 |website=www.wings-aviation.ch}}</ref><ref>{{Cite web |title=VS-27(2) |url=http://gonavy.jp/navy/sqn/VS27b.html |access-date=2022-09-02 |website=gonavy.jp}}</ref>{{unreliable source?|date=September 2022}}
** VS-28 Hukkers/Gamblers (1976-1992)<ref>{{Cite web |title=VS-28 (1960-1992) |url=http://gonavy.jp/navy/sqn/VS28.html |access-date=2022-09-02 |website=gonavy.jp}}</ref>{{unreliable source?|date=September 2022}}
** [[VS-29|VS-29 Dragonfires]] (1976-2004)<ref>{{Cite web |title=VS-29 |url=http://gonavy.jp/navy/sqn/VS29.html |access-date=2022-09-02 |website=gonavy.jp}}</ref>{{unreliable source?|date=September 2022}}
** VS-30 Diamond Cutters (1977-2007)<ref name="VS-30">{{Cite web |title=VS-30 |url=http://gonavy.jp/navy/sqn/VS30.html |access-date=2022-09-02 |website=gonavy.jp}}</ref>{{unreliable source?|date=September 2022}}
** [[VS-31|VS-31 Topcats]] (1977-2008)<ref name="VS-30"/>{{unreliable source?|date=September 2022}}
** [[VS-32|VS-32 Maulers]] (1976-2008)<ref>{{Cite web |title=VS-32 |url=http://gonavy.jp/navy/sqn/VS32.html |access-date=2022-09-02 |website=gonavy.jp}}</ref>{{unreliable source?|date=September 2022}}
** [[VS-33|VS-33 Screwbirds]] (1977-2006)<ref>{{Cite web |title=VS-33 |url=http://gonavy.jp/navy/sqn/VS33.html |access-date=2022-09-02 |website=gonavy.jp}}</ref>{{unreliable source?|date=September 2022}}
** [[VS-35 (1986–1988)|VS-35 Boomerangers]]/[[VS-35 (1990–2005)|Blue Wolves]] (1986-88/1991-2005)<ref>{{Cite web |title=VS-35 (1987-1988) |url=http://gonavy.jp/navy/sqn/VS35b.html |access-date=2022-09-02 |website=gonavy.jp}}</ref>{{unreliable source?|date=September 2022}}<ref>{{Cite web |title=VS-35(1991-2005) |url=http://gonavy.jp/navy/sqn/VS35c.html |access-date=2022-09-02 |website=gonavy.jp}}</ref>{{unreliable source?|date=September 2022}}
** [[VS-37|VS-37 Sawbucks]] (1978-1995)<ref>{{Cite web |title=VS-37 |url=http://gonavy.jp/navy/sqn/VS37.html |access-date=2022-09-02 |website=gonavy.jp}}</ref>{{unreliable source?|date=September 2022}}
** [[VS-38|VS-38 Red Griffins]] (1978-2004)<ref>{{Cite web |title=VS-38 |url=http://gonavy.jp/navy/sqn/VS38.html |access-date=2022-09-02 |website=gonavy.jp}}</ref>{{unreliable source?|date=May 2023}}
** [[VS-41|VS-41 Shamrocks]] (1974-2006)<ref>{{Cite web |title=VS-41 |url=http://gonavy.jp/navy/sqn/VS41.html |access-date=2022-09-02 |website=gonavy.jp}}</ref>{{unreliable source?|date=September 2022}}<ref>{{Cite web |title=VS-41 Sea Control Squadron FORTY ONE |url=https://www.globalsecurity.org/military/agency/navy/vs-41.htm |access-date=2022-09-02 |website=www.globalsecurity.org}}</ref>
** [[VQ-5|VQ-5 Sea Shadows]] (1991-1999)<ref>{{Cite web |title=VQ-5 |url=http://gonavy.jp/navy/sqn/VQ05.html |access-date=2022-09-02 |website=gonavy.jp}}</ref>{{unreliable source?|date=September 2022}}
** [[VQ-6|VQ-6 Black Ravens]] (1991-1999)<ref>{{Cite web |title=VQ-6 |url=http://gonavy.jp/navy/sqn/VQ06.html |access-date=2022-09-02 |website=gonavy.jp}}</ref>{{unreliable source?|date=September 2022}}
** [[VX-1|VX-1 Pioneers]] (Unknown)<ref>{{Cite web |title=VX-1 Air Test and Evaluation Squadron ONE [AIRTEVRON ONE] |url=https://www.globalsecurity.org/military/agency/navy/vx-1.htm |access-date=2022-09-02 |website=www.globalsecurity.org}}</ref>
* [[NASA]] (former)

==Aircraft on display==
[[File:Air Zoo December 2019 119 (Lockheed S-3 Viking).jpg|thumb|S-3 on display at the [[Air Zoo]]]]
;YS-3A
* 157993 – NAS Jacksonville Aircraft Heritage Park, [[NAS Jacksonville]], [[Jacksonville, Florida]].<ref>{{Cite web |title=Aircraft Heritage Park |url=https://cnrse.cnic.navy.mil/Installations/NAS-Jacksonville/About/History/Aircraft-Heritage-Park/ |access-date=2024-12-11 |website=cnrse.cnic.navy.mil}}</ref>
;S-3A
* 159417 – Celebrity Row, [[Davis-Monthan AFB]] (North Side), [[Tucson, Arizona]].{{Cn|date=October 2024}}
;ES-3A
* 159404 – Celebrity Row, Davis-Monthan AFB (North Side), Tucson, Arizona.{{Cn|date=October 2024}}
;S-3B
[[File:S-3 Viking PRNAM-2.jpg|thumb|S-3B on display at the Patuxent River Naval Air Museum]]
* 159387 – ''Navy One'' [[National Naval Aviation Museum]], [[NAS Pensacola]], [[Pensacola, Florida]].<ref>{{cite web |url = http://www.navalaviationmuseum.org/attractions/aircraft-exhibits/item/?item=s-3_navyone |title = S-3 Viking/159387 |publisher = National Naval Aviation Museum |access-date = 8 July 2015 |archive-date = 9 July 2015 |archive-url = https://web.archive.org/web/20150709162854/http://www.navalaviationmuseum.org/attractions/aircraft-exhibits/item/?item=s-3_navyone |url-status = dead }}</ref>
* 159412 – [[NAS North Island]], [[San Diego, California]].{{Cn|date=October 2024}}
* 159731 – {{USS|Yorktown|CV-10}} at the [[Patriot's Point]] Naval and Maritime Museum, [[Charleston, South Carolina]].<ref>{{cite web |url = http://www.patriotspoint.org/pdf/aircraft/s-3b_viking.pdf |title = S-3 Viking/159731 |publisher = USS Yorktown Museum |access-date = 8 July 2015}}</ref>
* 159743 – [[Aviation History & Technology Center]], [[Dobbins ARB]] (formerly Atlanta NAS), [[Atlanta, Georgia]].<ref>{{cite web |url = http://www.mariettahistory.org/aviation-wing |title = S-3 Viking/159743 |publisher = Aviation Wing of the Marietta Museum of History |access-date = 8 July 2015 |archive-date = 11 July 2015 |archive-url = https://web.archive.org/web/20150711004502/http://www.mariettahistory.org/aviation-wing |url-status = dead }}</ref>
* 159755 – NAS Pensacola, Pensacola, Florida.{{Cn|date=October 2024}}
* 159766 – {{USS|Midway|CV-41}} at [[San Diego, California]].<ref>{{cite web |url = http://www.midway.org/exhibits-and-activities?q=Aircraft-Museum |title = S-3 Viking/159766 |publisher = USS Midway Museum |access-date = 8 July 2015 |archive-date = 9 July 2015 |archive-url = https://web.archive.org/web/20150709163600if_/http://www.midway.org/exhibits-and-activities?q=Aircraft-Museum |url-status = dead}} {{Cite web |url=http://www.midway.org/exhibits-and-activities?q=Aircraft-Museum |title=Museum Aircraft Inventory Collection Spans WWII and Desert Storm &#124; USS Midway Aircraft Carrier Museum San Diego |access-date=8 July 2015 |archive-date=9 July 2015 |archive-url=https://web.archive.org/web/20150709163600if_/http://www.midway.org/exhibits-and-activities?q=Aircraft-Museum |url-status=live}}</ref>
* 159770 – [[Patuxent River Naval Air Museum]], [[Lexington Park, Maryland]].{{Cn|date=October 2024}}
* 160123 – [[Air Zoo]] at [[Kalamazoo, Michigan]].{{Cn|date=October 2024}}
* 160599 – {{USS|Hornet|CVS-12}} at the former [[NAS Alameda]], [[Alameda, California]].<ref>{{cite web |url = http://www.uss-hornet.org/exhibits/aircraft/jet/viking.shtml |title = S-3 Viking/160599 |publisher = USS Hornet Museum |access-date = 8 July 2015}}</ref>
* 160604 –  [[Pima Air and Space Museum]] (adjacent to Davis-Monthan AFB), Tucson, Arizona.<ref>{{cite web |url = http://www.pimaair.org/aircraft-by-name/item/lockheed-s-3b-viking |title = S-3 Viking/160604 |publisher = Pima Air and Space Museum |access-date = 8 July 2015 |archive-date = 27 June 2015 |archive-url = https://web.archive.org/web/20150627024335/http://www.pimaair.org/aircraft-by-name/item/lockheed-s-3b-viking |url-status = dead }}</ref>
* N601NA (160607) - ''NASA Viking'' [[San Diego Air & Space Museum]], [[San Diego]], [[California]].<ref name = "nasaretire ain"/>

==Specifications (S-3A)==
[[File:Lockheed S-3A Viking 0017.jpg|right|frameless|upright=1.35]]
{{Aircraft specs
|ref= ''Standard Aircraft Characteristics''<ref name=Navairs-3a>{{cite book |title = NAVAIR 00-110AS3-1 : Standard Aircraft Characteristics Model S-3A Aircraft |date = January 1973 |publisher = Naval Air Systems command |location = Washington D.C.}}</ref>
|prime units?= kts
<!--
        General characteristics
-->
|crew= 4 (pilot, co-pilot, [[Tactical coordinator|TACCO]], [[Airborne Sensor Operator|sensor operator]])
|length ft= 53
|length in= 4
|length note=
|span ft= 68
|span in= 8
|span note=
|width ft= 29
|width in= 6
|width note= folded
|height ft= 22
|height in= 9
|height note=
* '''Height tail folded:''' {{cvt|15|ft|3|in|0}}
|wing area sqft= 598
|wing area note=
|aspect ratio= 7.73
|airfoil= '''root:''' [[NACA airfoil|NACA 0016.3-1.03 32.7/100 mod]]; '''tip:''' [[NACA airfoil|NACA 0012-1.10 40/1.00 mod]]<ref name="Selig">{{cite web |last1 = Lednicer |first1 = David |title = The Incomplete Guide to Airfoil Usage |url = https://m-selig.ae.illinois.edu/ads/aircraft.html |website = m-selig.ae.illinois.edu |access-date = 16 April 2019}}</ref>
|empty weight lb= 26,581
|empty weight note=
|gross weight lb= 38,192
|gross weight note=
|max takeoff weight lb= 52,539
|max takeoff weight note=
|fuel capacity=
* '''Internal fuel capacity:''' {{cvt|1933|USgal|impgal L}} of [[JP-5]] fuel
* '''External fuel capacity:''' 2 × {{cvt|300|USgal|impgal L}} drop tanks
|more general=
<!--
        Powerplant
-->
|eng1 number= 2
|eng1 name= [[General Electric TF34-GE-2]]
|eng1 type= [[turbofan]] engines
|eng1 lbf= 9,275
|eng1 note=
<!--
        Performance
-->
|max speed kts= 429
|max speed note= at sea level
|max speed mach= 0.79
|cruise speed kts= 350
|cruise speed note=
|stall speed kts= 97
|stall speed note=
|never exceed speed kts=
|never exceed speed note=
|minimum control speed kts=
|minimum control speed note=
|range nmi= 2,765
|range note=
|combat range nmi= 460.5
|combat range note= <ref name="miltod">{{cite web |title = Lockheed S-3 Viking - Carrier-based anti-submarine and littoral warfare aircraft |url = http://www.military-today.com/aircraft/lockheed_s3_viking.htm |archive-url = https://web.archive.org/web/20070515232302if_/http://www.military-today.com/aircraft/lockheed_s3_viking.htm |url-status = usurped |archive-date = 15 May 2007 |access-date = 13 January 2020}}</ref>
|ferry range nmi= 3,368
|ferry range note=
|endurance=<!-- if range unknown -->
|ceiling ft= 40,900
|ceiling note=
|g limits=<!-- aerobatic -->
|roll rate=<!-- aerobatic -->
|climb rate ftmin= 5,120
|climb rate note=
|time to altitude=
|wing loading lb/sqft= 68.5
|wing loading note=
|fuel consumption lb/mi=
|thrust/weight= 0.353

|more performance=
<!--
        Armament
-->
|armament=
* Up to {{convert|4,900|lb|kg}} on 4 internal and 2 external hardpoints, including:
** 10 × {{convert|500|lb|kg}} [[Mark 82 bomb]]s
** 2 × {{convert|1000|lb|kg}} [[Mark 83 bomb]]s
** 2 × {{convert|2000|lb|kg}} [[Mark 84 bomb]]s
** 6 × [[CBU-100]] cluster bombs
** 2 × [[Mark 50 torpedo]]es
** 4 × [[Mark 46 torpedo]]es
** 6 × mines or depth charges
** 2 × [[B57 nuclear bomb]]s (depth charges)
** 2 × [[AGM-65]]E/F Maverick missiles
** 2 × [[AGM-84]]D Harpoon missiles
** 1 × AGM-84H/K [[SLAM-ER]] missile
* The underwing hardpoints can also be fitted with unguided rocket pods or 300&nbsp;US&nbsp;gal (1,136&nbsp;L) fuel tanks.
|avionics=
* AN/APS-116 sea search radar, maximum range {{convert|150|nmi|mi km|abbr=on}}
** Upgraded on S-3B to AN/APS-137 [[inverse synthetic aperture radar]] (ISAR)
* OR-89 [[forward looking infrared]] (FLIR) camera with 3× zoom
* AN/ARS-2 sonobuoy receiver with 13 blade antennas on the airframe for precise buoy location (sonobuoy reference system)
* AN/ASQ-81 [[magnetic anomaly detector]] (MAD)
* AN/ALR-47 electronic support measures (ESM) emitter-location system, with boxy receiver pods fitted to the wingtips, to locate adversary communications and radar transmitters
* AN/ASN-92 [[inertial navigation system]] (INS) with [[Doppler radar]] navigation and [[tactical air navigation system|TACAN]]
* Up to 60 sonobuoys (59 tactical, 1 search and rescue)
}}

==See also==
{{Portal|Aviation}}
{{aircontent
|related=
|similar aircraft=
* [[S-2 Tracker]]
* [[Fairey Gannet]]
* [[Bréguet 1050 Alizé]]
|lists=
* [[List of Lockheed aircraft]]
* [[List of military aircraft of the United States]]
|see also=
* [[CP-140 Aurora]]
}}

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

===Bibliography===
{{Refbegin}}
* Elward, Brad E."Lockheed S-3 Viking and ES-3A Shadow." ''World Air Power Journal'', Volume 34, Autumn–Fall 1998. {{ISBN|1-86184-019-5}}, pp.&nbsp;48–97.
* Francillon, René J. ''Lockheed Aircraft since 1913''. London: Putnam, 1982. {{ISBN|0-370-30329-6}}.
* Francillon, René J. ''Lockheed Aircraft Since 1913''. Naval Institute Press, 1987. {{ISBN|9780870218972}}.
* Godfrey, David W. H. "Fixer, Finder, Striker: The S-3A Viking." ''[[Air International]]'', Volume 7, Issue 1, July 1974, pp.&nbsp;5–13.
* Michell, Simon. ''Jane's Civil and Military Upgrades 1994–95''. Coulsdon, UK: Jane's Information Group, 1994. {{ISBN|0-7106-1208-7}}.
* [[John W. R. Taylor|Taylor, John W. R.]] ''Jane's All The World's Aircraft 1976–77''. London: Jane's Yearbooks, 1976. {{ISBN|0-354-00538-3}}.
* Winchester, Jim, ed. ''Military Aircraft of the Cold War'' (The Aviation Factfile). London: Grange Books plc, 2006. {{ISBN|1-84013-929-3}}.
* "Viking Variations". ''Air International'', Volume 31, Number 1, July 1986. pp.&nbsp;41–45.
* Norton, Bill. ''Bell Boeing V-22 Osprey, Tiltrotor Tactical Transport''. Earl Shilton, Leicester, UK: Midland Publishing, 2004. {{ISBN|1-85780-165-2}}.
{{Refend}}

==External links==
{{Commons category|Lockheed S-3 Viking}}
* [http://www.navy.mil/navydata/fact_display.asp?cid=1100&tid=1500&ct=1 S-3B Viking fact file] {{Webarchive|url=https://web.archive.org/web/20080928130041/http://www.navy.mil/navydata/fact_display.asp?cid=1100&tid=1500&ct=1 |date=28 September 2008 }} and [http://www.history.navy.mil/planes/s3.htm S-3 Viking history page on Navy.mil] {{Webarchive|url=https://web.archive.org/web/20090620232410/http://www.history.navy.mil/planes/s3.htm |date=20 June 2009 }}
* [http://www.thefreelibrary.com/S-3B+Viking%3A+war+hoover.-a0120703749 S-3 Viking: War Hoover] – ''Naval Aviation News'' (July–August 2004)

{{Lockheed Martin aircraft}}
{{US ASW aircraft}}
{{Authority control}}

[[Category:Aircraft first flown in 1972]]
[[Category:Lockheed aircraft|S-003]]
[[Category:1970s United States anti-submarine aircraft]]
[[Category:Twinjets]]
[[Category:Shoulder-wing aircraft]]
[[Category:Carrier-based aircraft]]
[[Category:Aircraft with retractable tricycle landing gear]]