Boeing YAL-1

Last updated

YAL-1 Airborne Laser
YAL-1A Airborne Laser unstowed crop.jpg
ABL aircraft during flight
Role Airborne Laser (ABL) anti-ballistic missile weapons system
Manufacturer Boeing
First flightJuly 18, 2002
RetiredSeptember 25, 2014
StatusCanceled
Primary user United States Air Force
Number built1
Developed from Boeing 747-400F
Career
Serial00-0001
FateScrapped

The Boeing YAL-1 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 missiles (TBMs) while in boost phase. The aircraft was designated YAL-1A in 2004 by the U.S. Department of Defense. [1]

Contents

The YAL-1 with a low-power laser was test-fired in flight at an airborne target in 2007. [2] A high-energy laser was used to intercept a test target in January 2010, [3] and the following month, successfully destroyed two test missiles. [4] Funding for the program was cut in 2010 and the program was canceled in December 2011. [5] 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

YAL-1 undergoing modification in November 2004, at Edwards AFB Yal1-edw-041103-wp-01.jpg
YAL-1 undergoing modification in November 2004, at Edwards AFB
Contractors dismantle the Boeing 747 fuselage portion of the System Integration Laboratory at the Birk Flight Test Center. Dismantling the System Integration Laboratory.jpg
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 NKC-135A. It shot down several missiles in tests conducted in the 1980s. [6]

The Airborne Laser program was initiated by the US Air Force in 1996 with the awarding of a product definition risk reduction contract to Boeing's ABL team. [7] [8] In 2001, the program was transferred to the U.S. Missile Defense Agency (MDA) and converted to an acquisition program. [8]

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. [8] [9]

In 2001, a retired Air India 747-200 was acquired by the Air Force and trucked without its wings from the 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. [10] [11] 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. [11]

The aircraft was built as a 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. [12] 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 ] 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 ]

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 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. [9]

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. [13]

In an April 6, 2009 press conference, the 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. [14]

There was a test launch off the California coast on June 6, 2009. [15] 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. [16]

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. [17]

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. [3] 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. [18] This test was the first time that a 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. [19] [20]

Cancellation

In storage with engines removed. Ultimately broken up on 25 September 2014. YAL-1 AMARG.JPG
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:

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 ... 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. [21]

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". [22] [23]

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. [24] [25] 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 309th Aerospace Maintenance and Regeneration Group until it was ultimately scrapped in September 2014 after all usable parts were removed. [26] [27]

As of 2013, studies were underway to apply the lessons of the YAL-1 by mounting laser anti-missile defenses on unmanned combat aerial vehicles that could fly above the altitude limits of the converted jetliner. [28]

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 40,000 feet (12 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 65,000 feet (20 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 55 kg (121 lb) to generate one kW, the MDA wanted to reduce that to 2–5 kg (4.4–11.0 lb) per kW, totaling 5,000 lb (2,300 kg) 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. [29]

Design

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.) USAF Airborne laser.jpg
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 kg). When fired, the laser used enough energy in a five-second burst to power a typical American household for more than an hour. [9]

Use against ICBMs vs TBMs

Laser Turret, said by the US Air Force to be the world's largest. Airbornelaserturret.jpg
Laser Turret, said by the US Air Force to be the world's largest.

The ABL was designed for use against tactical ballistic missiles (TBMs). These have a shorter range and fly more slowly than ICBMs. 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 ]

If the ABL had achieved its design goals, it could have destroyed liquid-fueled ICBMs up to 600 km away. Tougher solid-fueled ICBM destruction range would likely have been limited to 300 km, too short to be useful in many scenarios, according to a 2003 report by the American Physical Society on National Missile Defense. [30]

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. [31]

Operational considerations

A technician evaluates the interaction of multiple lasers for use aboard the Airborne Laser. Lasertests.jpg
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. [32]

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. [33] 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. [34]

Operator

Flag of the United States (23px).png  United States

Specifications

Data from[ citation needed ]

General characteristics

Performance

Armament

Avionics

See also

Related development

Aircraft of comparable role, configuration, and era

Related lists

Related Research Articles

<span class="mw-page-title-main">Anti-ballistic missile</span> Surface-to-air missile designed to counter ballistic missiles

An anti-ballistic missile (ABM) is a surface-to-air missile designed to counter ballistic missiles. Ballistic missiles are used to deliver nuclear, chemical, biological, or conventional warheads in a ballistic flight trajectory. The term "anti-ballistic missile" is a generic term conveying a system designed to intercept and destroy any type of ballistic threat; however, it is commonly used for systems specifically designed to counter intercontinental ballistic missiles (ICBMs).

<span class="mw-page-title-main">CIM-10 Bomarc</span> Long-range surface-to-air missile

The Boeing CIM-10 Bomarc was a supersonic ramjet powered long-range surface-to-air missile (SAM) used during the Cold War for the air defense of North America. In addition to being the first operational long-range SAM and the first operational pulse doppler aviation radar, it was the only SAM deployed by the United States Air Force.

<span class="mw-page-title-main">Missile</span> Self-propelled guided weapon system

A missile is an airborne ranged weapon capable of self-propelled flight aided usually by a propellant, jet engine or rocket motor.

<span class="mw-page-title-main">Aegis Ballistic Missile Defense System</span> United States Navy and Missile Defense Agency anti-ballistic missile program

The Aegis ballistic missile defense system, also known as Sea-Based Midcourse, is a Missile Defense Agency program under the United States Department of Defense developed to provide missile defense against short and intermediate-range ballistic missiles. The program is part of the United States national missile defense strategy and European NATO missile defense system.

<span class="mw-page-title-main">United States national missile defense</span> Nationwide missile defense program of the United States

National missile defense (NMD) refers to the nationwide antimissile program the United States has had in development since the 1990s. After the renaming in 2002, the term now refers to the entire program, not just the ground-based interceptors and associated facilities.

<span class="mw-page-title-main">Kirtland Air Force Base</span> US Air Force base at Albuquerque, NM, US

Kirtland Air Force Base is a United States Air Force base. It is located in the southeast quadrant of the Albuquerque, New Mexico, urban area, adjacent to the Albuquerque International Sunport. The base was named for the early Army aviator Col. Roy C. Kirtland. The military and the international airport share the same runways, making ABQ a joint civil-military airport.

<span class="mw-page-title-main">Ground-Based Midcourse Defense</span> United States anti-ballistic missile defense for intercepting warheads in space

Ground-Based Midcourse Defense (GMD) is the United States' anti-ballistic missile system for intercepting incoming warheads in space, during the midcourse phase of ballistic trajectory flight. It is a major component of the American missile defense strategy to counter ballistic missiles, including intercontinental ballistic missiles (ICBMs) carrying nuclear, chemical, biological or conventional warheads. The system is deployed in military bases in the states of Alaska and California; in 2018 comprising 44 interceptors and spanning 15 time zones with sensors on land, at sea, and in orbit. In 2019, a missile defense review requested that 20 additional ground-based interceptors be based in Alaska.

<span class="mw-page-title-main">Missile Defense Agency</span> Agency of the US Defense Department

The Missile Defense Agency (MDA) is a component of the United States government's Department of Defense responsible for developing a comprehensive defense against ballistic missiles. It had its origins in the Strategic Defense Initiative (SDI) which was established in 1983 by Ronald Reagan and which was headed by Lt. General James Alan Abrahamson. Under the Strategic Defense Initiative's Innovative Sciences and Technology Office headed by physicist and engineer Dr. James Ionson, the investment was predominantly made in basic research at national laboratories, universities, and in industry. These programs have continued to be key sources of funding for top research scientists in the fields of high-energy physics, advanced materials, nuclear research, supercomputing/computation, and many other critical science and engineering disciplines—funding which indirectly supports other research work by top scientists, and which was most politically viable to fund from appropriations for national defense. It was renamed the Ballistic Missile Defense Organization in 1993, and then renamed the Missile Defense Agency in 2002. The current director is U.S. Navy Vice Admiral Jon A. Hill.

<span class="mw-page-title-main">Advanced Tactical Laser</span> Experimental U.S. military program

The Advanced Tactical Laser (ATL) program was a US military program to mount a high energy laser weapon on an aircraft, initially the AC-130 gunship, for use against ground targets in urban or other areas where minimizing collateral damage is important. The laser was a 100 kilowatt-class chemical oxygen iodine laser (COIL). It was expected to have a tactical range of approximately twenty kilometres and weigh about 5,000–7,000 kg. This program is distinct from the Airborne Laser, which was a much larger system designed to destroy enemy missiles in the boost phase.

<span class="mw-page-title-main">Chemical oxygen iodine laser</span> US near-infrared chemical laser

A chemical oxygen iodine laser (COIL) is a near–infrared chemical laser. As the beam is infrared, it cannot be seen with the naked eye. It is capable of output power scaling up to megawatts in continuous mode. Its output wavelength is 1315 nm, a transition wavelength of atomic iodine.

An airborne laser (ABL) is a laser system operated from a flying platform, as in the:

<span class="mw-page-title-main">Laser weapon</span> Directed-energy weapon using lasers

A laser weapon is a type of directed-energy weapon that uses lasers to inflict damage. Despite decades of research and development, as of 2023, directed-energy weapons, including lasers, remain at the experimental stage. Whether they will be deployed as practical, high-performance military weapons remains to be seen. One of the major issues with laser weapons is atmospheric thermal blooming, which is still largely unsolved. This issue is exacerbated when there is fog, smoke, dust, rain, snow, smog, foam, or purposely dispersed obscurant chemicals present. In essence, a laser generates a beam of light that requires clear air or a vacuum to operate.

<span class="mw-page-title-main">Boeing NC-135</span> Type of aircraft

The Boeing NC-135 and NKC-135 are special versions of the Boeing C-135 Stratolifter and Boeing KC-135 Stratotanker modified to operate on several different programs.

<span class="mw-page-title-main">Beriev A-60</span> Soviet plane

The Beriev A-60 is a Russian airborne laser laboratory aircraft based on the Ilyushin Il-76MD transport— it was originally developed in the former Soviet Union for its airborne forces.

<span class="mw-page-title-main">Hypersonic flight</span> Flight at altitudes lower than 90km and at speeds above Mach 5

Hypersonic flight is flight through the atmosphere below altitudes of about 90 km at speeds greater than Mach 5, a speed where dissociation of air begins to become significant and high heat loads exist. Speeds over Mach 25 have been achieved below the thermosphere as of 2020.

The Space Tracking and Surveillance System was a pair of satellites developed by the United States Missile Defense Agency (MDA) to research the space-based detection and tracking of ballistic missiles. Data from STSS satellites could allow interceptors to engage incoming missiles earlier in flight than would be possible with other missile detection systems. The STSS program began in 2001, when the "SBIRS Low" program was transferred to MDA from the United States Air Force. In December 2002, SBIRS Low Research & Development was renamed Space Tracking and Surveillance System (STSS).

<span class="mw-page-title-main">417th Flight Test Squadron</span> Military unit

The 417th Flight Test Squadron is an active United States Air Force squadron. It is assigned to the 96th Operations Group at Eglin Air Force Base, Florida, where it was reactivated on 17 April 2019.

<span class="mw-page-title-main">452nd Flight Test Squadron</span> US Air Force unit

The 452d Flight Test Squadron is a United States Air Force squadron. It is assigned to the 412th Operations Group, Air Force Materiel Command, stationed at Edwards Air Force Base, California.

<span class="mw-page-title-main">Boeing Phantom Eye</span> Proposed unmanned aerial vehicle

The Boeing Phantom Eye was a high altitude, long endurance (HALE) liquid hydrogen-powered unmanned aerial vehicle developed by Boeing Phantom Works. The aircraft was Boeing's proposal to meet the demand from the US military for unmanned drones designed to provide advanced intelligence and reconnaissance work, driven by the combat conditions in Afghanistan in particular. In August 2016, the Phantom Eye demonstrator was disassembled for display at the Air Force Flight Test Museum.

In air and missile defense (AMD), the Integrated Air-and-Missile Defense system (IAMD) is an SMDC research program to augment the aging surface-to-air missile defense systems and to provide the United States Army with a low-cost, but effective complement to kinetic energy solutions to take out air threats. Brigade level higher energy lasers are used in truck mounted systems called HELMTT. At lower levels, the Army needs to develop interceptors that don't cost more than small, unmanned aircraft systems. In early research they have successfully used 5-kilowatt lasers on a Stryker combat vehicle. The Mobile Expeditionary High-Energy Laser (MEHEL) was used at MFIX at Fort Sill, Oklahoma, in the first half of April, 2017.

References

  1. "DoD 4120.15-L, Model Designation of Military Aerospace Vehicles" (PDF). U.S. Department of Defense. May 12, 2004. Archived from the original (PDF) on September 30, 2007.
  2. "Airborne Laser returns for more testing". Air Force. Archived from the original on March 8, 2007.
  3. 1 2 "Airborne Laser Test Bed Media Gallery". www.mda.mil.
  4. Wolf, Jim; Alexander, David (February 12, 2010). "U.S. successfully tests airborne laser on missile". reuters.com. Reuters.
  5. "Boeing YAL-1 Airborne Laser impacted by Pentagon spending priorities". Flight Image of the Day. Archived from the original on October 20, 2013.
  6. "Airborne Laser Laboratory". globalsecurity.org.
  7. "Airborne Laser:News". Archived from the original on July 22, 2010. Retrieved June 20, 2006.
  8. 1 2 3 "Airborne Laser Background presentation" (PDF). boeing.com. Archived from the original (PDF) on February 24, 2007.
  9. 1 2 3 Grill, Tech. Sgt. Eric M. (March 21, 2007). "Airborne Laser fires tracking laser, hits target". Air Force. Archived from the original on December 11, 2008.
  10. Radecki, Alan K. (2005). A Mojave Scrapbook. Mojave Books.
  11. 1 2 Hernandez, Jason (March 29, 2007). "Testers end high-energy laser tests, dismantle Airborne Laser SIL facility". USAF press release. Archived from the original on January 7, 2008.
  12. "00-0001 United States Air Force Boeing YAL-1A". www.planespotters.net. March 25, 2023. Retrieved February 25, 2024.
  13. "'Laser jumbo' testing moves ahead". bbc.co.uk. BBC News. July 29, 2008. Archived from the original on April 14, 2019. Retrieved June 17, 2019.
  14. "Local News – Boeing "hit harder" than rivals by defense budget cuts – Seattle Times Newspaper". nwsource.com. Archived from the original on April 10, 2009.
  15. "Home Security Systems : My Home Security". globalsecuritynewswire.org.
  16. "Boeing Airborne Laser Team Completes 1st Airborne Test Against Instrumented Target Missile". mediaroom.com (Press release). Edwards Air Force Base, California: The Boeing Company. August 13, 2009. Retrieved June 17, 2019.
  17. "Boeing: Boeing Airborne Laser Team Fires High-Energy Laser in Flight". mediaroom.com (Press release). Edwards Air Force Base, California: The Boeing Company. August 20, 2009. Retrieved June 17, 2019.
  18. "Airborne Laser Testbed Successful in Lethal Intercept Experiment". U.S. Department of Defense Missile Defense Agency. February 11, 2010. Archived from the original on February 15, 2010.
  19. Butler, Amy (March 19, 2010). "Next ABL Test To Require Twice as Much Range". Aviation Week Intelligence Network. Aviation Week & Space Technology. Archived from the original on December 30, 2022. Retrieved June 17, 2019 via aviationweek.com.
  20. Aviation Week & Space Technology, February 22, 2010, p. 26.
  21. "Missile Defense Umbrella?". Center for Strategic and International Studies. Archived from the original on January 11, 2011.
  22. "Schwartz: Get those AF boots off the ground". airforcetimes.com. Archived from the original on July 22, 2012.
  23. Hodge, Nathan (February 11, 2011). "Pentagon Loses War To Zap Airborne Laser From Budget" . The Wall Street Journal .
  24. Butler, Amy (December 21, 2011). "Lights Out For The Airborne Laser". Aerospace Daily & Defense Report. Aviation Week & Space Technology. Archived from the original on July 28, 2012 via aviationweek.com.
  25. Butler, Amy (December 20, 2011). "Lights Out For The Airborne Laser" . Aerospace Daily & Defense Report. Aviation Week & Space Technology . Retrieved June 17, 2019 via aviationweek.com.[ permanent dead link ]
  26. Nogee, Allen (May 6, 2014). "The Death of A Giant Laser". www.strategies-u.com. Strategies Unlimited. Retrieved June 17, 2019.
  27. "Google Maps".
  28. "MDA Eyes UAVs For Discrimination, Boost-Phase Kill". aviationweek.com.
  29. Return Of The ABL? Missile Defense Agency Works On Laser Drone - Breakingdefense.com, 17 August 2015.
  30. "APS Study". aps.org. Archived from the original on February 13, 2007.
  31. "How Does it work - Airborne Laser". www.airborne-laser.com.
  32. Congress (2011). Congressional Record. Government Printing Office. ISBN   9780160924286.
  33. Wright, David; Grego, Laura (December 9, 2002). "Anti-Satellite Capabilities of Planned US Missile Defense Systems". ucsusa.org. Union of Concerned Scientists. Archived from the original on December 11, 2005.
  34. http://goliath.ecnext.com/coms2/product-compint-0000806204-page.html [ dead link ]
  35. Lednicer, David. "The Incomplete Guide to Airfoil Usage". m-selig.ae.illinois.edu. Retrieved April 16, 2019.

32°9′17.4″N110°50′31″W / 32.154833°N 110.84194°W / 32.154833; -110.84194