Weapon Stats:

Cactus (Crotale) SAM

In July 1964, South Africa placed a development contract with the French company, Thomson-Houston (later Thomson-CSF) for a mobile, all-weather, low-altitude surface-to-air missile system. The Electronic Systems Division of Thomson-CSF was prime contractor for the complete system including the radar and electronics and Matra was responsible for the missile. The South African government paid 85 per cent of the development costs of the system, which it calls the Cactus, and the remaining 15 per cent was paid by France. The first firing was in 1967. After trials in 1971 the first of seven platoons was delivered to South Africa with the final one delivered in 1973.

In February 1971, the French Air Force placed its first order in February 1971, naming it Crotale, with several other countries following later.

The basic Crotale has an all-weather capability. A typical platoon consists of one Acquisition and Co-ordination Unit (ACU) and two to three firing units, with a battery having two platoons. All the operators, have one ACU vehicle to two firing units.

The ACU carries out target surveillance, identification and designation. Mounted on the top of the vehicle is a Thomson-CSF pulse Doppler radar with fixed-echo suppression which rotates at 60 rpm and has a maximum detection range of 18.5 km against low-level targets with speeds of between 35 and 440 m/s and altitude limits between zero and 4,500 m. The system also has an IFF interrogator-decoder. The computer, which is the same as that installed in the firing unit, is used to generate accurate data for confirmation of threat evaluation. Once the target has been detected, the computer triggers the IFF interrogator and the final threat information is displayed. The target is then allocated to one of the firing units and target designation data and operational orders are transmitted by the datalink which also supplies information from the firing unit on operational status, for example, the number of missiles available.

The firing unit has a J-band monopulse 17 km range single target tracking radar mounted concentrically with the launcher turret, which carries four ready to launch missiles, two each side. The system also has an I-band 10° antenna beamwidth command transmitter, differential angle-error measurement infrared tracking and gathering system with a +-5° wide field of view, an integrated TV tracking mode as a low-elevation back-up, an optical designation tripod-mounted binocular device (which is controlled manually by a handlebar arrangement and used primarily in a heavy ECM environment or whenever passive operation is required), computer, operating console and datalink. All the vehicles are fitted with an inter-vehicle link network to transmit data and orders by cable and for radio communication by a VHF radio link. The radar can track one target and guide one or two missiles simultaneously. The missiles, fired 2.5 seconds apart, are acquired immediately after launch by the 1.1° tracking beam of the radar with the help of infrared detection and radar transponders during the gathering phase. Initially the transponder was the 8,000 m range Thomson-CSF Stresa. Guidance signals are transmitted to the missiles by a remote-control system.

No spare missiles are carried on the vehicle and fresh missiles are brought up by a truck and loaded with a light crane. A well-trained crew of three can load four missiles in about two minutes. The missile is designated the R440 and weighs 84 kg, has an overall length of 2.89 m, span of 0.54 m and a diameter of 0.15 m. The missile complete with its transport/launch container weighs 100 kg. The HE high-energy focused fragmentation warhead in the centre of the missile weighs 15 kg, has a lethal radius of 8 m for the 2,300 m/s velocity fragments and is activated in the original R440 missiles by either the infrared proximity fuze (the fuze is commanded to activate 350 m before interception) or back-up contact fuze. The missile has an SNPE Lens III rocket motor with 25.45 kg of solid propellant powder. The missile reaches a maximum speed of 750 m/s in 2.8 seconds.

ADS have over the years upgraded the Cactus. The Acquisition Radar and missile Firing Unit (FU) mobile vehicles have been shelterised and the outdated computer systems have been replace. Using the new object-oriented software, the FU is able to fuse tracking data from the optical and radar sensors to achieve better quality tracking. Interfacing to Command and Control structures is also achieved.

120 Squadron operated several upgraded launchers and a fire-control post prior to the retirement of the Cactus sytem.

SPECIFICATIONS :

R440 Missile
Length: 2.89 m
Diameter: 0.15 m
Wing span: 0.54 m
Launch weight: 84 kg
Propulsion: solid propellant rocket motor
Guidance: command control
Warhead: 15 kg HE fragmentation with contact and proximity fuzing Max speed: 750 m/s
Max effective range: see text
Min effective range: see text
Max effective altitude: 5,000-5,500 m (depending upon target velocity)
Min effective altitude: 15 m
Reload time: 2 min (full 4-round load)