[6][7] This modularity allowed for the introduction of newer seekers and rocket motors, including the AIM-9C variant, which used semi-active radar homing and served as the basis of the AGM-122 Sidearm anti-radar missile.

This led to all-aspect capability in the L (Lima) version, which proved an effective weapon during the 1982 Falklands War and Operation Mole Cricket 19 in Lebanon.

Older variants such as the AIM-9B with uncooled seeker heads could only track the high temperatures of engine exhaust, making them strictly rear aspect.

Later variants, however, featured liquid nitrogen coolant bottles in the launchers, allowing the missile to track any part of the aircraft heated by air resistance due to high speed flight, giving modern Sidewinders all-aspect capabilities.

Instead, it uses rollerons, small metal discs protruding out of the aft end of the tips of the tail fins which spin as the missile flies through the air, providing gyroscopic stabilization.

Newer models of the AIM-9 sought to increase the range that the seeker head's gimbal can turn, allowing the missile to track aircraft at greater angles from its direct line of sight, or boresight.

The reticle spun at a fixed speed, causing the output of the photocell to be interrupted in a pattern, and the precise timing of the resulting signal indicated the bearing of the target.

Although Hamburg and similar devices like Madrid were essentially complete, the work of mating them to a missile had not been carried out by the time the war ended.

Several lengthy reports on the various systems were produced and disseminated among the Western aircraft firms, while a number of the engineers joined these companies to work on various missile projects.

[15][16] It did not receive official funding until 1951 when the effort was mature enough to show to Admiral William "Deak" Parsons, the Deputy Chief of the Bureau of Ordnance (BuOrd).

[17] The viewing angle of the AIM-9B's sensor was a minuscule 4 degrees, so at launch, the pilot had to accurately aim the aircraft's sight over or above the target (to account for drag).

It was famously the first Sidewinder variant to be fired in anger as on 24 September 1958, it achieved the world's first successful kill with an air-to-air missiles, when Taiwanese F-86Fs shot down Communist Chinese MiG-15s using AIM-9Bs supplied and fitted by the U.S. Navy (USN).

K-13R/R-3R (Object 320) (AA-2B/C Atoll): While the R-3S was being introduced in 1961, work started on a semi-active radar homing (SARH) version for high-altitude use, with 8 km range, similar to the little-used US Navy AIM-9C Sidewinder.

Finally, a new Mk 48 continuous-rod warhead was fitted to the missile for increased damage; this also meant infrared or a radio proximity fuze could be used.

A magnesium fluoride seeker dome was introduced, along with a more compact optical assembly, an improved guidance control system, new electronics, and significant changes to the internal wiring harnesses.

AIM-9E-2: Some "E" models are equipped with reduced-smoke rocket motors and have the designation AIM-9E-2 As the Sidewinder was being acquired by NATO forces, licensed production was given to West Germany and they would produce around 15,000 units.

Unnoticed improvements include solid state electronics (instead of vacuum tubes), carbon dioxide seeker cooling, a new nose dome and superior optical filtering.

When the engineers redesigned these electronics, they essentially kept the AIM-9G's optical system, but the tracking rate increased further, from the original 12˚ to 20˚ degrees per second, this complementing the more powerful 120 lb.ft actuators that had been installed.

On 8 June 1972, the AIM-9J was authorized for introduction into Southeast Asia under Phase IIA of its evaluation program, and approval to employ it in combat was received on 31 July 1972.

[27] The AIM-9X entered service in November 2003 with the USAF (the lead platform was the F-15C) and the USN (the lead platform was the F/A-18C) and is a substantial upgrade to the Sidewinder family featuring an imaging infrared focal-plane array (FPA) seeker with claimed 90° off-boresight capability, compatibility with helmet-mounted displays such as the new U.S. Joint Helmet Mounted Cueing System (JHMCS), and a totally new two-axis thrust-vectoring control (TVC) system providing increased turn capability over traditional control surfaces (60 g).

The USN projected that the new missile would have a 60 percent longer range, modern components to replace old ones, and an insensitive munitions warhead, which is more stable and less likely to detonate by accident, making it safer for ground crews.

The need for the AIM-9 to have an increased range was caused by digital radio frequency memory (DRFM) jammers that can blind the onboard radar of an AIM-120D AMRAAM, so the Sidewinder Block III's passive imaging infrared homing guidance system was seen as a useful alternative.

The Block III was scheduled to achieve initial operational capability (IOC) in 2022, following the increased number of F-35 Lightning II Joint Strike Fighters to enter service.

[44] However, the Navy's FY 2016 budget canceled the AIM-9X Block III as they cut down buys of the F-35C, as it was primarily intended to permit the fighter to carry six BVR missiles; the insensitive munition warhead will be retained for the AIM-9X program.

At the time, ROCAF North American F-86 Sabres were routinely engaged in air battles with the People's Republic of China over the Taiwan Strait.

In similar fashion to Korean War encounters between the F-86 and earlier MiG-15, high-flying PRC MiG-17s cruised above the ROC Sabres, immune to their .50-cal guns and only fighting when conditions favoured them.

[57] The fact that heat seeking Sidewinders were targeting hot jet exhausts against a cold background of the South Atlantic in winter resulted in a lethality rate of over 80 percent.

[51] On 4 February 2023, an F-22 Raptor operated by the United States Air Force used a single AIM-9X missile to shoot down a suspected Chinese spy balloon off the coast of Surfside Beach, South Carolina at an altitude between 60,000 to 65,000 feet (18,000 to 20,000 m).

[66] On 28 February 2018, the Iranian Islamic Revolutionary Guard Corps unveiled an anti-tank derivative of the Sidewinder missile named "Azarakhsh" intended for use by Bell AH-1J SeaCobra attack helicopters.

[71] In May 2019, the AIM-9X Block II was test fired from the National Advanced Surface to Air Missile System (NASAMS) at the Andøya Space Center in Norway.