View source for Boeing YAL-1

{{short description|Airborne laser demonstrator aircraft by Boeing}}
{{Use mdy dates|date=January 2015}}
<!-- This article is a part of [[Wikipedia:WikiProject Aircraft]]. Please see [[Wikipedia:WikiProject Aircraft/page content]] for recommended layout, and guidelines. -->
{{Infobox aircraft
 |name = YAL-1 Airborne Laser
 |image = File:YAL-1A Airborne Laser unstowed crop.jpg
 |caption = ABL aircraft during flight
 |type = [[Airborne Laser]] (ABL) [[anti-ballistic missile]] weapons system
 |manufacturer = [[Boeing]]
 |primary_user = [[United States Air Force]]
 |more_users = 
 |designer = 
 |first_flight = July 18, 2002
 |introduction = 
 |retired = September 25, 2014
 |status = Canceled
 |produced = 
 |number_built = 1
 |developed_from = [[Boeing 747-400F]]
 |variants = 
 |military_serial = 00-0001
 |fate = Scrapped
}}

The '''Boeing YAL-1''' [[Airborne Laser|airborne laser]] testbed was a modified [[Boeing 747-400F]] with a megawatt-class [[chemical oxygen iodine laser]] (COIL) mounted inside. It was primarily designed to test its feasibility as a [[missile defense]] system to destroy [[tactical ballistic missile]]s (TBMs) while in [[boost phase]]. The aircraft was designated '''YAL-1A''' in 2004 by the [[United States Department of Defense|U.S. Department of Defense]].<ref>{{cite web |url=http://www.dtic.mil/whs/directives/corres/pdf/412015l.pdf |archive-url=https://web.archive.org/web/20070930200603/http://www.dtic.mil/whs/directives/corres/pdf/412015l.pdf |url-status=dead |archive-date=September 30, 2007 |title=DoD 4120.15-L, Model Designation of Military Aerospace Vehicles |publisher= U.S. Department of Defense |date=May 12, 2004}}</ref>

The YAL-1 with a low-power laser was test-fired in flight at an airborne target in 2007.<ref>{{cite web |url=https://www.afmc.af.mil/news/story?id=123038913 |title=Airborne Laser returns for more testing |publisher=Air Force |url-status=live |archive-url=https://web.archive.org/web/20070308070103/http://www.afmc.af.mil/news/story.asp?id=123038913 |archive-date=March 8, 2007 |df=mdy }}</ref>  A high-energy laser was used to intercept a test target in January 2010,<ref name=ABL_2010_test /> and the following month, successfully destroyed two test missiles.<ref name="reuters">{{cite news |url=https://www.reuters.com/article/idUSN1111660620100212?type=marketsNews |title=U.S. successfully tests airborne laser on missile |publisher=[[Reuters]] | work = reuters.com | first1=Jim |last1=Wolf | first2=David | last2=Alexander |date=February 12, 2010}}</ref> Funding for the program was cut in 2010 and the program was canceled in December 2011.<ref>{{cite web | url = http://www.flightglobal.com/blogs/aircraft-pictures/boeing-yal-1-airborne-laser/ | title = Boeing YAL-1 Airborne Laser impacted by Pentagon spending priorities | work=Flight Image of the Day |url-status=dead |archiveurl=https://web.archive.org/web/20131020012544/http://www.flightglobal.com/blogs/aircraft-pictures/boeing-yal-1-airborne-laser/ |archive-date=October 20, 2013 }}</ref> It made its final flight on February 14, 2012, to [[Davis–Monthan Air Force Base]] near [[Tucson, Arizona]], to be kept in storage at the "boneyard" operated by the [[309th Aerospace Maintenance and Regeneration Group]]. It was ultimately scrapped in September 2014 after all usable parts were removed.

== Development ==

=== Origins ===
[[File:Yal1-edw-041103-wp-01.jpg|thumb|YAL-1 undergoing modification in November 2004, at [[Edwards AFB]] ]]
[[File:Dismantling the System Integration Laboratory.jpg|thumb|Contractors dismantle the Boeing 747 fuselage portion of the System Integration Laboratory at the Birk Flight Test Center.]]

The Airborne Laser Laboratory was a less-powerful prototype installed in a [[Boeing NC-135|Boeing NKC-135A]].  It shot down several missiles in tests conducted in the 1980s.<ref>{{cite web |url=http://www.globalsecurity.org/space/systems/all.htm|title= Airborne Laser Laboratory |publisher=globalsecurity.org}}</ref>

The Airborne Laser program was initiated by the [[United States Air Force|US Air Force]] in 1996 with the awarding of a product definition risk reduction contract to Boeing's ABL team.<ref>
{{Cite web |url=http://www.boeing.com/special/abl/news/ |title=Airborne Laser:News |access-date=June 20, 2006 |archive-url=https://web.archive.org/web/20100722004407/http://www.boeing.com/special/abl/news/ |archive-date=July 22, 2010 |url-status=dead |df=mdy-all }} 
</ref><ref name="overview">{{cite web |url=http://www.boeing.com/defense-space/military/abl/doc_src/ABL_overview.pdf |title=Airborne Laser Background presentation |publisher=boeing.com |url-status=dead |archiveurl=https://web.archive.org/web/20070224135448/http://www.boeing.com/defense-space/military/abl/doc_src/ABL_overview.pdf |archive-date=February 24, 2007 |df=mdy }}</ref> In 2001, the program was transferred to the U.S. [[Missile Defense Agency]] (MDA) and converted to an acquisition program.<ref name="overview" />

The development of the system was being accomplished by a team of contractors. [[Boeing Defense, Space & Security]] provides the aircraft, the management team, and the systems integration processes. [[Northrop Grumman]] was supplying the COIL, and [[Lockheed Martin]] was supplying the nose turret and the fire control system.<ref name="overview" /><ref name="atn1" />

In 2001, a retired [[Air India]] 747-200 was acquired by the Air Force and trucked without its wings from the [[Mojave Spaceport|Mojave Airport]] to [[Edwards Air Force Base]] where the airframe was incorporated into the System Integration Laboratory (SIL) building at Edwards' Birk Flight Test Center, to be used to fit check and test the various components.<ref>{{cite book |last=Radecki |first=Alan K. |title=A Mojave Scrapbook |publisher=Mojave Books |year=2005}}</ref><ref name="aerotech070406">{{cite web |last=Hernandez |first=Jason |url=https://www.edwards.af.mil/News/story/id/123046780/ |title=Testers end high-energy laser tests, dismantle Airborne Laser SIL facility |publisher=USAF press release |date=March 29, 2007 |url-status=live |archive-url=https://web.archive.org/web/20080107124906/http://www.edwards.af.mil/news/story.asp?id=123046780 |archive-date=January 7, 2008 |df=mdy }}</ref> The SIL was built primarily to test the COIL at a simulated operational altitude, and during that phase of the program, the laser was operated over 50 times, achieving lasing durations representative of actual operational engagements. These tests fully qualified the system so that it could be integrated into the actual aircraft. Following the completion of the tests, the laboratory was dismantled, and the 747-200 fuselage was removed.<ref name="aerotech070406" />

The aircraft was built as a [[Boeing 747-400F]] freighter at the [[Boeing Everett Factory]] with [[manufacturer's serial number]] 30201 and fuselage line number 1238. The aircraft took its first flight on 6 January 2000.{{Citation needed|date=September 2024}} It was shortly thereafter delivered to [[Boeing Defense, Space & Security]] in Wichita, Kansas for initial conversion for military use. The aircraft took to the skies again on 18 July 2002.{{Citation needed|date=February 2024}} Ground testing of the [[chemical oxygen iodine laser]] (COIL) resulted in its successful firing in 2004. The YAL-1 was assigned to the 417th Flight Test Squadron Airborne Laser Combined Test Force at Edwards AFB.{{Citation needed|date=August 2011}}

=== Testing ===
Besides the COIL, the system also included two kilowatt-class Target Illuminator Lasers for target tracking. On March 15, 2007, the YAL-1 successfully fired this laser in flight, hitting its target. The target was an [[Boeing NC-135|NC-135E]] ''Big Crow'' test aircraft that has been specially modified with a "signboard" target on its fuselage. The test validated the system's ability to track an airborne target and measure and compensate for atmospheric distortion.<ref name="atn1" />

The next phase in the test program involved the "surrogate high-energy laser" (SHEL), a stand-in for the COIL, and demonstrated the transition from target illumination to simulated weapons firing.  The COIL system was installed in the aircraft and was undergoing ground testing by July 2008.<ref name="bbc1">{{cite news|url=https://news.bbc.co.uk/1/hi/sci/tech/7531046.stm|publisher=[[BBC News]] | title = 'Laser jumbo' testing moves ahead|work=bbc.co.uk|date=July 29, 2008 | access-date = June 17, 2019 | archive-date = April 14, 2019 | archive-url = https://web.archive.org/web/20190414094816/http://news.bbc.co.uk/2/hi/science/nature/7531046.stm | url-status = live}}</ref>

In an April 6, 2009 press conference, the [[United States Secretary of Defense|Secretary of Defense]] [[Robert Gates]] recommended the cancellation of the planned second ABL aircraft and said that the program should return to a Research and Development effort. "The ABL program has significant affordability and technology problems and the program's proposed operational role is highly questionable," Gates said in making the recommendation.<ref>{{cite web |url=http://seattletimes.nwsource.com/html/localnews/2008997361_defensecuts07.html |title=Local News – Boeing "hit harder" than rivals by defense budget cuts – Seattle Times Newspaper |work=nwsource.com |url-status=dead |archiveurl=https://web.archive.org/web/20090410052937/http://seattletimes.nwsource.com/html/localnews/2008997361_defensecuts07.html |archive-date=April 10, 2009 |df=mdy }}</ref>

There was a test launch off the California coast on June 6, 2009.<ref>{{cite web|url=http://www.globalsecuritynewswire.org/gsn/nw_20090609_8318.php|title=Home Security Systems : My Home Security|work=globalsecuritynewswire.org|date=January 7, 2023 }}</ref> At that time it was anticipated that the new Airborne Laser Aircraft could be ready for operation by 2013 after a successful test. On August 13, 2009, the first in-flight test of the YAL-1 culminated with a successful firing of the SHEL at an instrumented test missile.<ref>{{cite press release|url=http://boeing.mediaroom.com/index.php?s=43&item=796|title=Boeing Airborne Laser Team Completes 1st Airborne Test Against Instrumented Target Missile|work=mediaroom.com|date=August 13, 2009|location=[[Edwards Air Force Base]], California|access-date=June 17, 2019|publisher=[[The Boeing Company]]}}</ref>

On August 18, 2009 the high-energy laser aboard the aircraft successfully fired in flight for the first time. The YAL-1 took off from Edwards Air Force Base and fired its high-energy laser while flying over the California High Desert. The laser was fired into an onboard calorimeter, which captured the beam and measured its power.<ref>{{cite press release | url = http://boeing.mediaroom.com/index.php?s=43&item=803 | title = Boeing: Boeing Airborne Laser Team Fires High-Energy Laser in Flight | work = mediaroom.com | publisher = [[The Boeing Company]] | date = August 20, 2009 | location = [[Edwards Air Force Base]], California | access-date = June 17, 2019}}</ref>

In January 2010, the high-energy laser was used in-flight to intercept, although not destroy, a test ''Missile Alternative Range Target Instrument'' (MARTI) in the boost phase of flight.<ref name="ABL_2010_test">{{cite web | url = https://www.mda.mil/news/gallery_altb.html | title = Airborne Laser Test Bed Media Gallery | website = www.mda.mil}}</ref>  On February 11, 2010, in a test at Point Mugu Naval Air Warfare Center-Weapons Division Sea Range off the central California coast, the system successfully destroyed a liquid-fuel boosting ballistic missile. Less than an hour after that first missile had been destroyed, a second missile—a solid-fuel design—had, as announced by the MDA, been "successfully engaged", but not destroyed, and that all test criteria had been met. The MDA announcement also noted that ABL had destroyed an identical solid-fuel missile in flight eight days earlier.<ref>{{cite web |url=http://www.mda.mil/news/10news0002.html |title=Airborne Laser Testbed Successful in Lethal Intercept Experiment |publisher=U.S. Department of Defense Missile Defense Agency |date=February 11, 2010 |url-status=dead |archiveurl=https://web.archive.org/web/20100215081702/http://www.mda.mil/news/10news0002.html |archive-date=February 15, 2010 |df=mdy-all }}</ref> This test was the first time that a [[directed-energy weapon|directed-energy]] system destroyed a ballistic missile in any phase of flight.  It was later reported that the first February 11 engagement required 50% less dwell time than expected to destroy the missile, the second engagement on the solid-fuel missile, less than an hour later, had to be cut short before it could be destroyed because of a "beam misalignment" problem.<ref>{{Cite news | url = https://aviationweek.com/awin/next-abl-test-require-twice-much-range-0 | title = Next ABL Test To Require Twice as Much Range | date = March 19, 2010 | first = Amy | last = Butler | work = Aviation Week Intelligence Network | via = aviationweek.com | publisher = [[Aviation Week & Space Technology]] | access-date = June 17, 2019 | url-access = subscription | archive-date = December 30, 2022 | archive-url = https://web.archive.org/web/20221230145952/https://aviationweek.com/awin/next-abl-test-require-twice-much-range-0 | url-status = dead }}</ref><ref>''Aviation Week & Space Technology'', February 22, 2010, p. 26.</ref>

=== Cancellation ===
[[File:YAL-1 AMARG.JPG|thumb|In storage with engines removed. Ultimately broken up on 25 September 2014.]]
Secretary of Defense Gates summarized fundamental concerns with the practicality of the program concept:
<blockquote>
I don't know anybody at the Department of Defense, Mr. Tiahrt, who thinks that this program should, or would, ever be operationally deployed. The reality is that you would need a laser something like 20 to 30 times more powerful than the chemical laser in the plane right now to be able to get any distance from the launch site to fire&nbsp;... So, right now the ABL would have to orbit inside the borders of Iran in order to be able to try and use its laser to shoot down that missile in the boost phase. And if you were to operationalize this you would be looking at 10 to 20 747s, at a billion and a half dollars apiece, and $100 million a year to operate. And there's nobody in uniform that I know who believes that this is a workable concept.<ref>{{cite web|url=http://csis.org/blog/missile-defense-umbrella |title=Missile Defense Umbrella? |publisher=[[Center for Strategic and International Studies]] |url-status=dead |archiveurl=https://web.archive.org/web/20110111093235/http://csis.org/blog/missile-defense-umbrella |archive-date=January 11, 2011 |df=mdy }}</ref>
</blockquote>

The Air Force did not request further funds for the Airborne Laser for 2010; Air Force Chief of Staff Schwartz has said that the system "does not reflect something that is operationally viable".<ref>{{cite web |url=http://www.airforcetimes.com/news/2010/02/airforce_budget_022610w/ |archive-url=https://archive.today/20120722014125/http://www.airforcetimes.com/news/2010/02/airforce_budget_022610w/ |url-status=dead |archive-date=2012-07-22 |title=Schwartz: Get those AF boots off the ground |publisher=airforcetimes.com}}</ref><ref>{{cite news | last = Hodge | first = Nathan | url = https://www.wsj.com/articles/SB10001424052748704570104576124173372065568 | title = Pentagon Loses War To Zap Airborne Laser From Budget | newspaper=[[The Wall Street Journal]] | date= 11 February 2011 | url-access = subscription}}</ref>

In December 2011, it was reported that the project was to be ended after 16 years of development and a cost of over US$5 billion.<ref>{{cite web | url = http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=defense&id=news%2Fasd%2F2011%2F12%2F21%2F02.xml&headline=Lights+Out+For+The+Airborne+Laser|archive-url=https://archive.today/20120728205518/http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=defense&id=news/asd/2011/12/21/02.xml&headline=Lights+Out+For+The+Airborne+Laser | url-status = dead | archive-date = 28 July 2012 | title = Lights Out For The Airborne Laser | first = Amy | last = Butler| work = Aerospace Daily & Defense Report | publisher = [[Aviation Week & Space Technology]] | via = aviationweek.com | date = 21 December 2011 | url-access = registration}}</ref><ref>{{cite web | url = https://aviationweek.com/awin/lights-out-airborne-laser-0 | title = Lights Out For The Airborne Laser | first = Amy | last = Butler | work = Aerospace Daily & Defense Report | publisher = [[Aviation Week & Space Technology]] | via = aviationweek.com | date = 20 December 2011 | url-access = subscription | access-date = June 17, 2019 }}{{Dead link|date=October 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> While in its current form, a relatively low power laser mounted on an unprotected airliner may not be a practical or defensible weapon, the YAL-1 testbed is considered to have proven that air mounted energy weapons with increased range and power could be another viable way of destroying otherwise very difficult to intercept sub-orbital ballistic missiles and rockets. On 12 February 2012, the YAL-1 flew its final flight and landed at [[Davis-Monthan AFB]], Arizona, where it was placed in storage at the "boneyard" operated by the [[AMARG|309th Aerospace Maintenance and Regeneration Group]] until it was ultimately scrapped in September 2014 after all usable parts were removed.<ref>{{cite web|url=http://www.strategies-u.com/articles/2014/05/the-death-of-a-giant-laser.html | title = The Death of A Giant Laser | website = www.strategies-u.com | publisher = Strategies Unlimited | date = May 6, 2014 | first = Allen | last = Nogee | access-date = June 17, 2019}}</ref><ref>{{cite web|url=https://www.google.com/maps/@32.1547999,-110.8419426,93m/data=!3m1!1e3?hl=en|title=Google Maps}}</ref>

As of 2013, studies were underway to apply the lessons of the YAL-1 by mounting laser anti-missile defenses on [[unmanned combat aerial vehicle]]s that could fly above the altitude limits of the converted jetliner.<ref>{{cite web|url=http://www.aviationweek.com/Article/PrintArticle.aspx?id=/article-xml/asd_08_16_2013_p01-01-607382.xml&p=1&printView=true|title=MDA Eyes UAVs For Discrimination, Boost-Phase Kill|work=aviationweek.com}}</ref>

By 2015, the [[Missile Defense Agency]] had started efforts to deploy a laser on a high-altitude UAV.  Rather than a manned jetliner containing chemical fuels flying at {{convert|40000|ft|km}}, firing a megawatt laser from a range of "tens of kilometers" at a boost-phase missile, the new concept envisioned an unmanned aircraft carrying an electric laser flying at {{convert|65000|ft|km}}, firing the same power level at targets potentially up to "hundreds of kilometers" away for survivability against air defenses.  While the ABL's laser required {{convert|55|kg|lb|abbr=on}} to generate one kW, the MDA wanted to reduce that to {{convert|2|-|5|kg|lb|abbr=on}} per kW, totaling {{convert|5,000|lb|kg|abbr=on}} for a megawatt.  Unlike the ABL, which required its crew to rest and chemical fuel to be reloaded, an electric laser would need only power generating from fuel to fire, so a UAV with in-flight refueling could have near-inexhaustible endurance and armament.  A "low-power demonstrator" was planned to fly sometime in or around 2021.<ref>[http://breakingdefense.com/2015/08/return-of-the-abl-missile-defense-agency-works-on-laser-drone/ Return Of The ABL? Missile Defense Agency Works On Laser Drone] - Breakingdefense.com, 17 August 2015.</ref> Challenges in reaching required power levels on a platform with sufficient performance led to the MDA choosing not to pursue the concept.<ref>[https://www.twz.com/news-features/u-s-military-laser-weapon-programs-are-facing-a-reality-check U.S. Military Laser Weapon Programs Are Facing A Reality Check]. ''The War Zone''. 21 May 2024.</ref>

== Design ==
[[File:USAF Airborne laser.jpg|thumb|Artist impression of two YAL-1As shooting down ballistic missiles. The laser beams are highlighted red for visibility. (In reality, they would be invisible to the naked eye.)]]

=== COIL ===
The heart of the system was the COIL, comprising six interconnected modules, each as large as an [[SUV]].  Each module weighed about 6,500 pounds (3,000&nbsp;kg).  When fired, the laser used enough energy in a five-second burst to power a typical American household for more than an hour.<ref name="atn1">{{cite web|author=Grill, Tech. Sgt. Eric M. |url=https://www.af.mil/News/story/id/123045745/ |title=Airborne Laser fires tracking laser, hits target |publisher=Air Force |date=March 21, 2007 |url-status=live |archive-url=https://web.archive.org/web/20081211212241/http://www.af.mil/news/story.asp?id=123045745 |archive-date=December 11, 2008 |df=mdy }}</ref>

=== Use against ICBMs vs TBMs ===
[[File:Airbornelaserturret.jpg|thumb|upright|Laser Turret, said by the US Air Force to be the world's largest.]]

The ABL was designed for use against [[tactical ballistic missile]]s (TBMs). These have a shorter range and fly more slowly than [[ICBM]]s.  The MDA had suggested the ABL might be used against ICBMs during their boost phase. This could require much longer flights to get in position, and might not be possible without flying over hostile territory.  Liquid-fueled ICBMs, which have thinner skins, and remain in boost phase longer than TBMs, might be easier to destroy.{{Citation needed|date=August 2011}}

If the ABL had achieved its design goals, it could have destroyed liquid-fueled ICBMs up to 600&nbsp;km away.  Tougher solid-fueled ICBM destruction range would likely have been limited to 300&nbsp;km, too short to be useful in many scenarios, according to a 2003 report by the [[American Physical Society]] on [[National Missile Defense]].<ref>{{cite web |url=http://www.aps.org/about/pressreleases/boosts2.cfm |title=APS Study |publisher=aps.org |url-status=dead |archiveurl=https://web.archive.org/web/20070213231108/http://www.aps.org/about/pressreleases/boosts2.cfm |archive-date=February 13, 2007 |df=mdy }}</ref>

=== Intercept sequence ===
The ABL system used infrared sensors for initial missile detection.  After initial detection, three low-power tracking lasers calculated missile course, speed, aimpoint, and air turbulence.  Air turbulence deflects and distorts lasers.  The ABL [[adaptive optics]] use the turbulence measurement to compensate for atmospheric errors.  The main [[laser]], located in a turret on the aircraft nose, could be fired for 3 to 5 seconds, causing the missile to break up in flight near the launch area.  The ABL was not designed to intercept TBMs in the terminal or descending flight phase.  Thus, the ABL would have had to be within a few hundred kilometers of the missile launch point.  All of this would have occurred in approximately 8 to 12 seconds.<ref>{{cite web|url=http://www.airborne-laser.com/how_does_it_work.php|title=How Does it work - Airborne Laser|website=www.airborne-laser.com|access-date=March 18, 2018|archive-date=March 23, 2016|archive-url=https://web.archive.org/web/20160323025610/http://www.airborne-laser.com/how_does_it_work.php|url-status=usurped}}</ref>

=== Operational considerations ===
[[File:Lasertests.jpg|thumb|upright|A technician evaluates the interaction of multiple lasers for use aboard the Airborne Laser.]]

The ABL did not burn through or disintegrate its target. It heated the missile skin, weakening it, causing failure from high-speed flight stress. The laser used chemical fuel similar to rocket propellant to generate the high laser power. Plans called for each 747 to carry enough laser fuel for about 20 shots, or perhaps as many as 40 low-power shots against fragile TBMs. To refuel the laser, YAL-1 would have to land. The aircraft itself could have been refueled in flight, which would have enabled it to stay aloft for long periods. Preliminary operational plans called for the ABL to be escorted by fighters and possibly [[electronic warfare]] aircraft. The ABL aircraft would likely have had to orbit near potential launch sites (located in hostile countries) for long periods, flying a figure-eight pattern that allows the aircraft to keep the laser aimed toward the missiles.<ref>{{cite book| author = Congress| title = Congressional Record| url = https://books.google.com/books?id=oj5jAMspUfAC&pg=PA11290| year = 2011| publisher = Government Printing Office | isbn = 9780160924286}}</ref>

=== Use against other targets ===
In theory, an airborne laser could be used against hostile fighter aircraft, cruise missiles, or even low-Earth-orbit satellites (see [[anti-satellite weapon]]). However, the YAL-1 infrared target acquisition system was designed to detect the hot exhaust of TBMs in boost phase. Satellites and other aircraft have a much lower heat signature, making them more difficult to detect. Aside from the difficulty of acquiring and tracking a different kind of target, ground targets such as armored vehicles and possibly even aircraft are not fragile enough to be damaged by a megawatt-class laser.

An analysis by the [[Union of Concerned Scientists]] discusses potential airborne laser use against low Earth orbit satellites.<ref>{{cite web 
 | url = http://www.ucsusa.org/global_security/space_weapons/asat-capabilities-of-us-missile-defense-systems.html | title = Anti-Satellite Capabilities of Planned US Missile Defense Systems | work = ucsusa.org | publisher = [[Union of Concerned Scientists]] | date = December 9, 2002 | first1 = David | last1 = Wright | first2 = Laura | last2 = Grego | author2-link = Laura Grego | url-status = dead | archive-url = https://web.archive.org/web/20051211090828/http://www.ucsusa.org/global_security/space_weapons/asat-capabilities-of-us-missile-defense-systems.html | archive-date = December 11, 2005 |df=mdy }}</ref> Another program, the [[Advanced Tactical Laser]], envisions air-to-ground use of a megawatt-class laser mounted on an aircraft better suited for low altitude flight.<ref>http://goliath.ecnext.com/coms2/product-compint-0000806204-page.html {{Dead link|date=September 2022}}</ref>

==Operator==
;{{USA}}
* [[United States Air Force]]
** [[417th Flight Test Squadron]] - [[Edwards Air Force Base|Edwards AFB]], [[California]]

== Specifications ==
{{Aircraft specs
|ref={{citation needed|date=May 2019}}
|prime units?=kts
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|eng1 name=[[General Electric CF6-80C2B5F]]
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|eng1 kn=276
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|max speed kts=547.5
|max speed note=at {{cvt|35000|ft}}
|max speed mach=<!-- supersonic aircraft -->
|cruise speed kts=499.5
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|more performance=
<!--
        Armament
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|armament=
* 1 × [[Chemical oxygen iodine laser|COIL]] (Chemical oxygen iodine laser)
|avionics=
* 1 × ABL infrared detector system
* 2 × Target Illuminator lasers
}}

== See also ==
{{aircontent
|see also=
* [[Advanced Tactical Laser]]
* [[High Energy Liquid Laser Area Defense System]]
* [[Tactical High Energy Laser]]
|related=
* [[Boeing 747]]
* [[Boeing 747-400]]
|similar aircraft=
* [[Beriev A-60]]
* [[Boeing NC-135|Boeing NKC-135A]]
|lists=
* [[List of laser articles]]
* [[List of military aircraft of the United States]]
}}

== References ==
{{Reflist|2}}

== External links ==
{{Commons category}}
* [http://educatedearth.net/video.php?id=4526 Laser test – video footage]{{Dead link|date=September 2025 |bot=InternetArchiveBot }}
* [http://www.airforce-technology.com/projects/abl/ YAL-1 ABL page]
* {{usurped|1=[https://web.archive.org/web/20081217072943/http://www.airborne-laser.com/ Site dedicated to the Airborne laser]}}
* [https://web.archive.org/web/20060208105508/http://www.triplehelix.com/missileintercept.avi An animation depicting the laser interception of a ballistic missile. (AVI format)]
* [http://phys.org/news/2015-08-boeing-weapon-drones-laser-welding.html Boeing's Compact Laser Weapon System]

{{Boeing military aircraft}}
{{lone designation|system=US tri-service Airborne Laser aircraft|designation=L-1}}
{{USAF transports}}
{{747 military variants}}
{{Boeing model numbers}}

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[[Category:Military lasers]]
[[Category:Missile defense]]
[[Category:Boeing 747]]
[[Category:Boeing aircraft|YAL-1]]
[[Category:2000s United States experimental aircraft]]
[[Category:Quadjets]]
[[Category:Directed-energy weapons of the United States]]
[[Category:Air Force Research Laboratory projects]]
[[Category:Low-wing aircraft]]
[[Category:Aircraft first flown in 2002]]
[[Category:Aircraft with retractable tricycle landing gear]]