Photo for representational purposes only.

The Russian invasion of Ukraine has given rise to the possibility of the conflict spreading regionally is forcing Finland to think more seriously about its defense. To this end Helsinki aims to improve its air defense capabilities and has liked Israel’s mobile air defense systems which uses Python 5 and Derby missiles.

Spider Air Defense System

Spider ADS is an Israeli mobile anti-aircraft missile system developed by two Israeli companies, IAI and Rafael Advanced Defense systems. The company’s product line has four possible air defense systems including Spyder MFU-SR, Spyder MFU-ER, Spyder MFU-MR / LR, and Spyder MFU-AIO SR / ER.

The primary difference between the four is mostly in the extent of the defeat. So far it is not clear which of the four systems Finland is interested in. If one were to hazard a guess, it would be the medium-range air defense system.

The system consists of a truck-mounted command and control unit, along with a radar, missiles and a built-in EC sensor. The number of missiles will depend on the modification. The system is based on an open architecture allowing the integration of external components, including hardware or software.

Its average range is up to 20 km and its characteristic is that of dual-use: air-to-air or surface-to-air missiles. It can fire both Python-5 and Derby missiles.


All four air defense systems can fire both missiles. The difference is that in the medium and long-range variations, the missiles use an additional booster assembly.

Military experts consider the Python-5 to be a modern air-to-air missile. The missile has a dual-band infrared [IIR] and CCD Seeker, and the ability to “lock-on after launch” (LOAL) when the target is out of sight.

The missile was first used in 2006 by a F-16 Fighting Falcon in the Lebanese war. It brought down two Iranian Ababil UAVs.

The Python-5 missile is a little over 3 meters long with a diameter of 16 cm and weighs around 105 kilograms; the warhead integrated into the missile weighs 11 kg. It can fly at speeds above Mach 4.

Derby missile

The Derby is a Beyond Visual Range (BVR) missile with experts saying it is a continuation of the Phyton missile. With 3.5 meters in length, it weighs 118 kg. Its warhead weighs 23 kg. It has a range of nearly 40 km and can fly at Mach 4.

It appears Finland is interested in an air defense system that uses the latest version of this missile – the I-Derby ER. Until 2015, Israel denied the existence of this missile. This variant has an extended range and can hit targets at up to 100 km.

The I-Derby ER is the preferred missile for many fighter jets, including Su-30MKI and India’s Tejas. For years, India has been trying to negotiate a purchase of these missiles.