Defense Express reported the information.Designed for advanced fighter jets like the Su-35 and Su-57, this missile is a heavily modernized version of the Soviet-era R-77.Ukrainian sources have confirmed the use of the R-77M by Russian forces, publishing images of missile fragments recovered from recent incidents.From R-77 to R-77MThe original R-77 (also known by its export name RVV-AE, internal designation Izdelie 170, or K-77) was developed in the 1980s by the Vympel Design Bureau as a Soviet counterpart to the U.S. AIM-120 AMRAAM. It was one of the first Russian missiles to feature an active radar homing seeker, a major technological leap at the time. The R-77 became operational in the 1990s with a maximum range of around 70–80 km and was visually distinctive due to its lattice control fins.However, those lattice fins proved problematic. While intended to deploy mid-flight, they often increased aerodynamic drag and radar visibility, reducing the effectiveness of both the missile and the launching aircraft.In 2003, work began on an improved version — the R-77-1 (also known as RVV-SD, Izdelie 170-1, or K-77-1). Completed in the early 2010s, the R-77-1 featured a more powerful radar seeker, a secondary passive guidance channel for use in jamming environments, and improved aerodynamics.Arrival of Izdelie 180 (K-77M)Development of the latest variant, Izdelie 180 (K-77M/R-77M), began in the 2010s as part of the armament for Russia’s fifth-generation Su-57 fighter. This version eliminated the problematic lattice fins in favor of a more conventional design. Although the K-77M is theoretically sized to fit within the Su-57’s internal weapons bay, photos published by Russian sources show it carried externally on underwing pylons.According to Russian claims, the K-77M boasts a range of up to 190 km, thanks to a new dual-pulse solid-fuel engine. However, such figures typically apply only when engaging targets at high altitudes and in optimal conditions. The missile is also said to feature an active electronically scanned array (AESA) radar seeker, enhancing its target tracking and lock-on reliability.While Russian media have reported for several years that the missile was nearing operational readiness, it appears to have only recently been deployed in combat. In addition to the Su-57, the Su-35 is now confirmed to carry the R-77M, as shown in recently released Russian media images.New threat to Ukrainian aircraftThe introduction of the K-77M increases the threat posed by Russian high-altitude patrol tactics, long dominated by the R-37 air-to-air missile. Although the R-37 has a claimed range of 400 km, its real-world performance falls far short of that. The K-77M, with a more realistic range and advanced seeker, represents a more credible danger to Ukrainian aircraft.It's important to note that the actual effective range of any missile depends heavily on conditions, including the speed, altitude, and direction of both the launching jet and the target. Russian sources tend to present these figures under ideal circumstances.Nevertheless, the deployment of a longer-range missile with an advanced seeker presents new challenges. It may require Ukraine to upgrade its aircraft electronic warfare (EW) systems to defend against the missile’s improved radar guidance and tracking capabilities.