Technical Specifications

Combat weight: 28.3ton 
Length: 10.21m 
Width: 3.00m 
Height: 3.15m 
Chassis Length: 6.60m 
Chassis Width: 2.80m 
Ground Clearance: 0.45m 
Ground Pressure: 180kPa 
Calibre: 155mm, 39 
Calibre Max. Range: 30km with ER projectile 
Max. Rate: 6 rds / min 
Burst Rate: 3 rds / 20 secs 
Sustained Rate: 2 rds / min for 30 mins 
Secondary Weapon: 7.62 mm 
GPMG Operating Range: 350 km Top Speed: 50 km/h 
Transmission: GDDS-HMPT-500-3EC 
Engine: 550HP Detroit 
Diesel Emplacement Time: < 1 min 
Displacement Time: 1 min Crew: 4 men

The SSPH 1 Primus

The SSPH 1 Primus is a 155mm, 39 calibre track-based, self-propelled howitzer developed jointly by the Singapore Armed Forces (SAF), Defence Science & Technology Agency (DSTA) and Singapore Technologies Kinetics (ST Kinetics), to meet the operational requirements of the SAF.

A fusion of the range and firepower of the artillery, with the protection, speed and maneuverability of armoured vehicles, the Primus is a highly accurate, mobile artillery platform that will bolster the fighting capabilities of our Combined Arms Division armoured forces with its ‘hide, shoot and scoot’ capability.

Arguably the lightest and most responsive self-propelled howitzer in its class, the Primus packs a big punch to any target within its range. Onboard, the ingenious integration of technologies allows a crew of four to effectively operate the system autonomously; affirming the Primus not only as a formidable force in the modern battlefield, but also as an invaluable asset to our technologically advanced army.

Designed developed and produced in Singapore, the Primus is a clear testament of our innovation and industry. An achievement that Singapore can be proud of.


The realisation of six years of development, the Primus is the latest in a line of projects that the three organisations have collaborated on. Others include the Artillery’s Field Howitzer 88 (FH88), the Field Howitzer 2000 (FH2000), the BRONCO All-Terrain Tracked Carrier, the BIONIX Armoured Fighting Vehicle, and the SAR21 Assault Rifle.

The experience garnered from these past successes has proven beneficial in the development of this new system. The Primus is our most technologically complex product designed to date, as it includes sophisticated on-board computers and innovative automation. It is also the lightest and most responsive, fully autonomous self-propelled howitzer in its class, setting it apart from its towed predecessors and other self-propelled howitzers alike.

The genesis of a self-propelled howitzer within the SAF was conceived in the early 1990s, with the aim of replacing the self-propelled mortars and providing better fire support to the armour brigades in the Combined Arms Division. This new weapon system would require the ability to keep pace with the high tempo of armoured operations, while providing the range, firepower and accuracy that the artillery is renowned for. The 155mm, self-propelled Howitzer was seen as the obvious choice.

Several commercial-off-the-shelf (COTS) systems such as the M109A6 paladin (USA), Type 75 (Japan), 2S3M1 (Ex-Soviet) and the AS90 Braveheart (UK) that fulfilled the prerequisites of possessing firepower with the high mobility and battlefield survivability were considered. However, none could cater to our unique requirements in terms of lightweight mobility; hence the decision was made by DSTA to develop a completely new SPH with ST Kinetics.

With that, in May 1996, the Primus development began.

From the onset, the major challenge the team encountered was in designing a platform that could satisfy all the required specifications. DSTA and ST Kinetics had to deliver an SPH that not only matched the performance of other SPHs available in the market, but one that would suit the SAF’s unique operational needs.

Some of these specifications included the ability to navigate and move on paved and soft soil terrain, common in our area of operations, as well as the capability to ‘come into action’ rapidly. Being lightweight would provide our SPH with this unprecedented mobility, thus emphasis was placed on limiting its weight. As a result, most of the system and its sub-components were customised to suit the SAF, and a large portion of the design work went into enhancing the weapon system performance through automation, increasing its efficiency and effectiveness.

The result is a closed loop Automated Fire Control System consisting of five main subsystems, ranging from the patented Ammunition Handling System to the Laser Ring Gyroscopic Navigation & Positioning System. In developing the Primus, DSTA was involved in assessing and reviewing the various design proposals by ST Kinetics and subsequently integrating the various components and subsystems into what it is today. ST Kinetics, meanwhile, worked on the system, bringing its technical expertise and production know-how on artillery systems, leveraging on the experience it has gained through other large calibre weapon systems previously developed such as FH88 and FH2000.

Both agencies conducted extensive and intensive trials to test design reliability and safety as well as to prove that the SPH could deliver the desired operational performance. During the rollout phase, they looked into quality assurance issues and conducted acceptance tests on each SPH before delivery. Long-term equipment maintenance, promulgation and retention of knowledge were other areas of focus.

Finally in April 2000, the first working prototype of the Primus was rolled-out by ST Kinetics. The next two years saw the system undergo a series of comprehensive tests to ensure that the Primus was able to withstand the rigours that were required of it. In September 2002, the Primus was officially certified to have met the SAF’s stringent criteria, bringing to a close the successful evolution of an idea realised.

SPH Development Timeline

May 96 Contract Signed 
Sep – Dec 96 Preliminary Design Review 
Jul – Dec 99 Critical Design Review 
Apr 00 Prototype Roll-Out 
Apr 00 – Dec 01 Developmental Tests & Evaluation 
Jan – Jun 02 User Trial 
Jul – Sep 02 Final Design Review 
Sep 02 Production

The evolution of the Primus, from drawing board to final product, is proof of Singapore’s capabilities to not only operate state-of-the-art equipment but also the capacity to produce them indigenously. This speaks volumes of our homegrown industry in developing world-class systems that are on par, if not better than systems currently available in the global market. The SAF, together with its partners, DSTA and ST Kinetics, have once again proven, with the development of the SSPH1 Primus, that we need only look within our borders for solutions to our needs.

The fact sheet above was issued to the media by Mindef Public Affairs.