A US Air Force F-22 Raptor popped a Chinese “spy balloon” on February 4 using an AIM-9X Sidewinder missile, marking the first kill for the mighty Raptor. Interestingly, this wasn’t the first time the Sidewinder had destroyed a Chinese target.
The Sidewinder is the world’s first heat-seeking missile and is the most widely used missile in the West, with at least 27 nations operating the missile, other than the United States.
It is undoubtedly one of the most significant innovations in guided missile technology in the last 60 years, revolutionizing air warfare.
It all began in 1946 at the Naval Ordnance Test Station (NOTS), Inyokern, California, which has now become the Naval Air Weapons Station China Lake, where the US Navy physicist William B McLean came up with a novel idea during his work with the lead-sulfide proximity fuzes that were sensitive to infrared radiation.
Maclean reasoned that if a proximity fuze could read infrared signatures to initiate detonation, they should also be able to track infrared signatures, based on which he envisioned a missile that would adjust its course mid-flight to keep the target’s heat signature reflected onto a sensitive photocell.
Thus, making the missile seek heat.
Maclean began working on his concept independently with a small team of volunteers and laboratory funding, designating the effort as ‘Local Fuze Project 602.’
His concept entailed a gyroscopically spinning magnet that would reflect the emissions from a heat source onto a sensitive photocell. When the source moves away from the gyro’s axis, the photocell generates a signal in a coil surrounding the magnet, prompting it to turn its axis toward the mobile heat source.
By 1950, Maclean came up with a name for his missile, ‘the Sidewinder,’ inspired by a snake that can detect its prey by sensing its body heat. Interestingly, the missile’s movement in the air also resembled that of a serpent.
Maclean’s developmental work did not receive official funding until 1951 when it was mature enough to show to Admiral ‘Deak’ Parsons, the Deputy Chief of the Bureau of Ordnance (BUORD). It subsequently received designation as a program in 1952.
Just one year later, in 1953, McLean’s Sidewinder missile successfully shot down its first target drone in a training environment, demonstrating the effectiveness of his concept.
The AIM-9 Sidewinder finally entered service in 1956. The nine-foot-long missile, with a glass nose containing its internal guidance system, had no means of pilot control after it was launched.
