The Kaliningrad K-5 (NATO reporting name AA-1 'Alkali'), also known as RS-1U, was the first Soviet air-to-air missile.

History

The development of the K-5 began in 1951. The first test firings were in 1955. It was tested (but not operationally carried) by the Yakovlev Yak-25. The weapon entered service as the RS-2U in 1957. The initial version was matched to the RP-2U (Izumrud-2) radar used on the MiG-17PFU, MiG-19PM. An improved variant, K-5M or RS-2US in PVO service, entered production in 1959, matched to the RP-9/RP-9U Safir radar of the Sukhoi Su-9. The People's Republic of China developed a copy under the designation PL-1.

The difficulties associated with beam-riding guidance, particularly in a single-seat fighter aircraft, were substantial, making the 'Alkali' primarily a short-range anti-bomber missile. Around 1967 the K-5 was replaced by the K-55 (R-55 in service), which replaced the beam-riding seeker with the semi-active radar homing or infrared seekers of the K-13 (AA-2 'Atoll'). The weapon was 7.8 kg (17.2 lb) heavier than the K-5, but had a smaller 9.1 kg (20.1 lb) warhead. The K-55 remained in service through about 1977, probably being retired with the last of the front-line Sukhoi Su-9 interceptors.

Specifications (RS-2US / K-5M)

• Length: 2500 mm (8 ft 2 in)
• Wingspan: 654 mm (2 ft 2 in)
• Diameter: 180 mm (7.1 in)
• Launch weight: 83.2 kg (183.4 lb)
• Speed: 2,320 km/h(1,440 mph)
• Range: 2-6 km (1.25-3.75 mi)
• Guidance: beam riding
• Warhead: 15.2 kg (33.5 lb)