been sold widely, with China and India placing significant orders for the munition, as was the case for the R-73. The baseline R-77 was designed in the 1980s, with development complete by around 1994. India was the first export customer for the export variant, known as the RVV-AE, with the final batch delivered in 2002. There are other variants under development. One has an upgraded motor to extend a range at high altitudes to as much as 120–160 km; it is known as the RVV-AE-PD (Povyshenoy Dalnosti—improved range). This variant has been test-fired and uses a solid-fuel ramjet engine. Its range puts it in the long-range class and is equivalent in range to the AIM-54 Phoenix. In another version of the R-77, a terminal infrared homing seeker is offered. This is in line with the Russian practice of attacking targets by firing pairs of missiles with different homing systems. This complicates end-game defensive actions for the target aircraft, as it needs to successfully defeat two homing systems. If a radar-guided medium-range missile is fired at an enemy jet aircraft outside the non-escape attack zone, the target aircraft may be able to escape through emergency maneuver. But at this moment, in fact, the infrared guidance has an advantage: once the jet aircraft turns to escape, the engine nozzle is exposed, and the infrared characteristics are exposed. This method of attack may not always be available as IR seekers typically have less range and less resistance to poor weather than radar seekers, which may limit the successful use of mixed seeker attacks unless the IR missile is initially directed by radar or some other means. Another improvement program was designated the R-77M, which made the missile longer and heavier, making use of a two-stage motor as well as an improved seeker. A further product-improvement of the R-77, designated the R-77M1 and then the R-77-PD, was to feature a ramjet propulsion device. This missile was destined for the MiG 1.44 that for the MFI program. The munition has a laser fuse and an expanding rod warhead that can destroy the variable sized targets. However, due to funding shortage and eventual cancellation of the MiG 1.44, development of this model may have stopped by 1999; no information or announcement regarding the R-77M and R-77-PD has appeared since. Further development Tactical Missile Weapons Corporation, also known as TRV (Takticheskoe Raketnoe Vooruzhenie – Тактическое Ракетное Вооружение),