MiG-31 Fighter Force To Get Upgrade.

Russia's Defence Ministry has signed a 30 billion rouble ($630 million) contract with a major state-owned aircraft manufacturer to modernize over 50 of its high-speed MiG-31 interceptor jets, the RIA Novosti news agency reported.

MiG-31 Fighter Force To Get Upgrade.

The move comes amid a 20 trillion rouble ($500 billion) ongoing state rearmament program and rising tensions over Ukraine that have seen Russian jets repeatedly test the boundaries of NATO airspace in recent months.

"The armed forces will receive over 50 modernized MiG-31s by the end of 2018," RIA quoted Deputy Defense Minister saying. The modernization will be carried out by Russia's largest aircraft manufacturer, United Aircraft Corporation.

The MiG-31 is a classic Soviet aircraft. Designed in the 1970s as a follow on to the MiG-25 supersonic interceptor jet, the plane is a supersonic bomber killer.

Around 120 of the fighters remain in service today, RIA reported.

The MiG-31 is capable of intercepting and destroying any target from low-flying satellites to cruise missiles. A group of interceptors can control a large portion of air space, by directing fighters to any target, as well as ground-based anti-aircraft missiles.

This aircraft was called the “flying radar” by the pilots, for its unique avionics capabilities. This complex has at its basis the ‘Barrier’ control system, equipped with the world’s first phased-array antenna. This PAA differs from the classic radar as it allows to move the beam at a fixed antenna, as well as to create the necessary number of rays, tracking multiple targets simultaneously.

Modernized MiG-31s are outfitted with new avionics and fire control systems, and can simultaneously fire on six targets within a 280-kilometre radius.

The U.S. and most other Western air forces phased out dedicated bomber interceptors by the time the MiG-31 entered service in 1975, as the focus of Soviet nuclear strategy focused on ballistic missiles. However, the Soviets saw continued need to operate fighters capable of dealing with the comparatively massive U.S. strategic bomber fleet in the event of nuclear conflict.

Russia has already modernized around 20 MiG-31s, according to media reports. A separate contract to modernize 60 of the aircraft by 2020 was signed with United Aircraft Corporation in 2011.