The missile

The complete missile weighed over two tonnes composed of two stages joined by pyrotechnic fasteners (designed to separate the two stages when the propellant in the first had been exhausted). The missile had a range of 55 km (34 mi) and possessed a large, for an anti-aircraft weapon, 100 kg (220 lb) high explosive (HE) blast fragmentation warhead. This was perhaps to overcome shortcomings in accuracy as, coupled with a proximity fuse, any aircraft the missile failed to hit could still be caught in its blast.

The booster was designed to expend all its fuel in about 5 seconds, accelerating the missile to a velocity of 800 m/s (2,600 ft/s) on separation. After separation of the two stages, and the missile was heading towards the target at a terminal velocity of Mach 3, the terminal radar guidance system was initiated.

This mode of operation meant that the missile had a minimum intercept altitude of 30 metres (98 ft) which in theory left it unable to intercept sea skimming anti-ship missiles and low flying aircraft. However even blind the 100 kg (220 lb) warhead meant that some result would have been achieved.

MASURCA was manufactured in three versions:

• The Mark 1: this was a basic version, it was used during all qualification tests but also for a time aboard the Suffren.
• The Mark 2 Mod 2: this was the first operational version. This relatively primitive version was retired in 1975.
• The Mark 2 Mod 3: this was the last operational version.

The weapon system

Laymen tend to think of a weapon system as consisting only of the weapon itself, in this case the missile, however with MASURCA (and for that matter most missile systems) this is far from the truth.

Suffren seen from aft port, to the stern is the twin armed MASURCA launcher, forward of which (in two tiers) are the fire control radars, the large radome conceals the DRBI-23 three-dimensional radar.

The MASURCA weapon system consisted of:

• A twin arm launcher of 40 t (39 long tons; 44 short tons), 4 m (4.4 yd) high and 4.45 m (4.87 yd) wide, trainable in elevation and azimuth. Providing the initial direction of the missile to the target, it could launch missiles at elevations from +6° to +70°.
• A working chamber located to the rear of the launch arms and pedestal. This chamber permitted the mounting and unfolding of the rear tail control services and facilitated the loading of the missiles onto the launch arms.
• A magazine consisting of two horizontal silos for the storage of 17 ready to fire missiles and space for a single missile to undergo verification for proper operation
• A magazine for the storage of unassembled missiles.
• A missile assembly cradle. It was difficult to assemble more than 12 missiles in a day's work, in particular ceramic components within the missiles were very susceptible to shock damage during assembly.
• Two DRBR-51 tracking radars with two associated illuminators
• Fire control Computer
• A single DRBI-23 three-dimensional radar
• A single SENIT 2 automatic tactical information processor
• Target designators for weapon assignment

Whereas the weight of 48 missiles is 96 t (94 long tons; 106 short tons), counting the entire weapon system as a whole, the weight was closer to 450 t (440 long tons; 500 short tons). This great weight imposed a limit on the minimum hull size that could deploy the system, and was one reason why MASURCA was limited to only three ships of the French Navy.

Operation of the mod 2 and 3, and constraints

MASURCA utilised semi-active radar homing for terminal guidance requiring radar illumination of the target by its parent warship. This was provided by two groups of DRBR-51 tracking and illumination radars, allowing MASURCA equipped ships to simultaneously engage two targets.

Once a target had been identified by the DRBI-23 three-dimensional radar and prioritised, the two DRBR-51 radars would be locked onto the two most dangerous targets and once they have come into range the missiles would be fired.

Missiles could be launched before targets come into range, anticipating their future position. It was also possible for more than two missiles to be launched simultaneously. Although only two could be actively controlled, the launch arms would send the following missiles in the right direction. If the first two missiles were destroyed or had missed, the following missiles could be immediately gathered in to re-attack the same target or, if the first target had been destroyed, allocated to attack another. However, at two tonnes, the MASURCA missile was not the easiest of missiles to handle, and reloading of the launch arms was relatively long, leading to a delay between the first and any subsequent salvo of missiles.

This mode of operation was common to both the service variants of the MASURCA, the mod 2 and the mod 3. The mod 2 was relatively primitive, the missile had no way of perceiving the target other than through the proximity fuse, the missile operating in effect as a command guided one, the accuracy of the missile dependent on the tracking systems ability to maintain a lock on the target which could become indistinct with increasing range, altitude and speed of the target.

The final service version, the mod 3, was a true semi-active radar homing (SARH) missile with a continuous-wave radar receiver built into the missile, which homed in on the CW radar return of the illumination radar. This CW return, reflected from the target, would be scattered in all directions however the closer the missile came to the target, the "brighter" the target would appear increasing the chance of a hit. In addition the reaction time of the missile reduced as the range to the target decreased, which was not true of the radio controlled mod 2.