Development history of the M35A2 Cataphract Main Battle Tank

Background and origins

The genesis of the M35A2 Cataphract Main Battle Tank can be traced to a series of design studies conducted by the Etoile Arcture Defence Research Agency (EADRA) from 1977-1983. The purpose had been to investigate possible replacements for the then-current in-service M18 Currasier main battle tank of the Etoile Arcture Ground Forces viewed as being too lightly protected and armed (with a 105 mm main gun) to meet threats postulated to exist by the 1990s. From these studies emerged the three-crew 'Sports Model' tank concept that owed much of its inspiration to the Swedish S-tank and the Israeli Merkava. Among its features was a long wedge-shaped hull, a centre hull fighting compartment accessable by a rear crew hatch, front-mounted powerpack and transmission providing added protection to the crew, and a low profile unmanned turret mounting an autoloading main gun with ammunition stored in a compartmentalised turret bustle. In 1986 the General Secretariat authorised the Directorate-General for Defence (aka Defence Directorate) of Etoile Arcture to initiate the definition phase of the XM35 Future Main Battle Tank (FMBT) program, also known as Project Byzantium, using the 'Sports Model' as its starting point. The next phase of development focused on subsystems including propulsion, drive trains, sensors and armament. The project in fact mirrored work also also being performed across the world at this time e.g., Component Advanced Technology Testbed (CATTB) or M1 Abrams Block III (United States), Experimentalwanne Gesamtschutz (EGS) (Germany), Neuer Kampfpanzer (Switzerland) and Strv 2000 (Sweden). By 1992 the state of the XM35 FMBT/Project Byzantium had become as follows:

• Target gross vehicle weight of Military Load Class 60 (MLC 60) or approximately 55.4 tons all up at the highest protection level;

• High survivability by combination of low radar, acoustic, visual and thermal signatures and multi-layer protection consisting a suite of modified rolled homogenous armour (MHRA) base armour with V-shaped blast deflecting belly plate, appliqué modular replaceable composite armour, explosive reactive armour and soft- and hard-kill active protection systems;

• Modular design of the chassis, subsystem components and armament systems adaptable for technology insertion and future upgrades;

• A three person crew protected under armour in a chemical, biological, radiological and nuclear CBRN) protected centre hull fighting compartment;

• Manpower and Personnel Integration (MANPRINT) digital crew stations and indirect vision systems for superior under armour all-weather day/night situational awareness
  situational awareness;

• Digital full solution fire control system for high hit probability of all weapons using high-speed computers networked by digital multiplex databus;

• Low profile turret or turretless external gun mount for a low recoil force gun: either a dual calibre 140/120 mm high-velocity gun or a 120 mm electro-thermal chemical (ETC) gun, depending on which matured the soonest, with the backup option of a conventional 140 mm or 120 mm smoothbore gun;

• Development of new ammunition including a APFSDS round with a minimum muzzle velocity of 18 MJ and capable of 50% greater range and penetration than current ammunition, a gun-launched long-range laser beam riding top-attack and anti-helicopter round, and obstacle removal and less lethal munitions;

• 40 mm coaxial autocannon or under armour 50-60 mm spigot mortar as secondary armament, and a remote-operated 12.7 mm self-defence/anti aircraft machine gun;

• High mobility over all terrain provided by adjustable external in-arm hydrogas hydropneumatic suspension, electric transmission and final drives using a series-parallel hybrid-electric power train with the power source based on a compact 1,500-2,000 hp high fuel economy diesel engine or advanced gas turbine engine.

Cancellation

XM35 Future Main Battle Tank prototype as rolled out in 1996. This example
is in the test mobility configuration with a dummy non-traversing turret fitted.

Many aspects of the XM35 FMBT design configuration represented a high order of risk, with most of the planned technology at low technology readiness levels. Nonetheless, the possible high rewards if successfuly developed convinced the Defence Directorate to grant authority to proceed unilaterally. Work begun in 1990 with Marine Steel Works (later to become part of Sequoia Defence Systems and eventually Sequoia Dynamics) selected as the prime contractor. Marine Steel Works had overall responsibility for the hull, turret and integration of the final product, with subsystems including weapons, sensors and propulsion spun out to various industrial partners and a select number of foreign component suppliers. Twenty sets of XM35 FMBT prototype tanks had been produced by 1993: eight based on an experimental (and therefore high-risk) hybrid-electric drive train, and the remainder using conventional engines and transmissions derived those used by the in-service M18A3 Currasier. Both prototype classes unfortunately
fell short of expectations with neither demonstrating any superior performance or reliability compared to third-generation threats like the M1 Abrams, Challenger II, Leopard 2 and AMX-56 Leclerc that were being fielded at this time.
Much of the blame for this was placed on an ever changing set of requirements from the customer resulting in schedule slippages and budget overruns. As a result the Assembly of Representatives, with oversight over the program, had lost confidence in its management and goals and voted to withdraw funding during the 1997 financial year, in effect cancelling the program. To fill the operational gap this left, with the Defence Directorate still needing to find a replacement for their aging M18A3 Currasier tank fleet, they were directed to begin the XM22 Interim Main Battle Tank (IMBT) program to find a suitable stopgap replacement from a foreign supplier. Following an open competition the decision was made to procure the M8 Lariat main battle tank designed and built by the Allis-Chalmers Corporation of Coorsota, which when modified to Etoilian specifications was type classified as the M22 Jackal, with 58,000 units being eventually produced from 1998-2007. To support the industrial base of the new tank fleet Sequoia Defence Systems and Allis-Chalmers formed a joint venture known as Sequoia-Allis Defence Services to develop versions for both the Coorsota Defence Forces (CDF) and Etoile Arcture Ground Forces (EAGF). This partnership resulted in the M8 Lariat 1A1L 'Long Arm' turret version and M8 Lariat 1A2 upgrade for the CDF, and the M22A2HA or 'Heavy Armour' variant for the EAGF. The final production version of the M22A2HA would sport an armour suite, MANPRINT digital crew stations, vehicle electronics (vetronics) suite, third-generation thermal sights, lidar weapon sight and improved fire control and battle management system originally slated for the FMBT program but now ironically developed under the banner of the IMBT program and rolled into its design as upgrades to create an advanced fourth-generation tank.

Rebirth and renewal of the 'forgotten tank'

The operational service of the M22A2 Jackal, which saw extensive combat service during the Alestran Civil War against the Leopard 2A4 and the first Fegosian civil war against the M1A4 Wolfhound proved highly exemplary. But the mid-2000s onwards witnessed a trend towards heavier armoured and armed designs among foreign tank fleets being typified by the Sumerian MCA-7 Ubara Tirak, Lyran LY4 Wolfhound and increasingly ubiquitous Macabean Nakil series, that were all in the Military Load Class (MLC) 70-80 (63.5-71.43 ton) range and sporting advanced 120-140 mm main guns. With these so-called fifth-generation tanks beginning to proliferate within Nova too the M22A2HA Jackal itself received a new 140 mm main gun and its armour protection increased until reaching a total curb weight of 68 tons. Nonetheless, it was quickly recognised that Etoile Arcture would need its own fifth-generation tank to counter the emerging threat, and faced with protracted lead times in developing any new tank from a clean sheet design, the Defence Directorate successfully lobbied that the existing XM35 FMBT modular chassis design could be used as a basis for newly developed 'drop in' technology to dramatically reduce the development effort and cost. Consequently, in 2001 the General Secretariat reinstated Project Byzantium as a Phase 2 program and type-classified the tank in preparation for its service entry as the M35A2-2000 Cataphract. Responsibility for the design was transferred from Marine Steel Works to its parent company Sequoia Defence Systems who could use the experience they had gained on the IMBT program. The fact that the XM35 FMBT had been designed from the outset with a modular upgradeable architecture now paid dividends as engineers could insert mature technologies into the chassis that had been either unavailable or technologically immature at the time of the original development effort. Many of these were integrated into the existing chassis as production cut-ins, including the Ramcyclone high fuel efficient supersonic combustion engine (ASCE) simple-cycle gas turbine recently developed by Synergy Electrodynamics, permanent magnet (PM) generators and traction motors developed by Genista Electrosystems, and third-generation hydrogas variable spring rate in-arm suspension developed by Colibri Automotive Works. A new developmental item was a low profile turret to mount the primary armament which would be a 120 mm solid propellant electro-thermal chemical gun (SPECTER) based on direct electrical ignition (plasma injection) technology and robot ammunition handling system (RAILS). Both systems had already reached full maturity having been in development since the mid-1990s to replace the Sumerian AGS.250B 120 mm regenerative liquid propellant gun (RLPG) and Flashboard Large Area Emitter (FLARE) ignition system used on early models of the M22A2 Jackal which had to be imported from Coorsota as no Etoilian company held a license to produce it, a situation unhappy at the best of times and thoroughly miserable at the worst i.e., a time of war if supplies could not be guaranteed.

Finally ordered into servce

M35A2-2020 Catphract Main Battle Tank with A-kit armour in 2018.

In 2004 new XM35 test rigs and pre-production M35A1 Cataphract hulls were produced by Sequoia Defence Systems, fabricated in extra-low interstitial (ELI) titanium armour as opposed to the all-welded steel or modified rolled homogeneous armour (MHRA) used on the original XM35 test articles. This decision would have major ramifications on protection and performance, saving approximately five tons in gross weight that allowed a heavier (and better protected) appliqué armour suite to be fitted to the hull and an enhanced protection suite to the turret. Recent advances in superscalar processing technology also had far-reaching impacts on the implementation of drive-by-wire systems, electronic engine management, digital fire control systems and sensor suites but most of all in shared datalinks and networking through the Battlefield Information Collection and Distribution System (BICDS) and JEWEL Waveband software-defined radio multi-band communication system that had already been introduced on the M22A2HA Jackal, M65CA7 Talon+ and M344 Wolverine combat vehicles. These electronic systems featured robust rad-hardened processors and would represent more than 50% of the total cost of each weapon system.
The program quickly progressed to a number of pre-production M35A2-2000 Block I Cataphract tanks, with delivery of the first production models occurring in mid-2007. Following months of trials, the type was accepted into service by the Etoile Arcture Ground Forces in the early part of 2008, almost 12 years to the day of the first rollout of the original XM35 prototype. By the time of the Cyncia Civil War of 2009 the production standard had been finalised on the M35A2-2000 Block II Cataphract which had received a number of updates, most notably the addition of an elevated sensor mast inspired by that used by Coorsota on the M8 Lariat 1A2. The M35A2-2000 Block II proved decisive in tank-on-tank battles in Cyncia and later in the same year in Thive, and in urban combat operations in Alfegos during the second Fegosian civil war. This combat experience fed into the upgrade of the platform to the current M35A2-2020 Cataphract production standard that saw significant updates including a new 2,000 hp powerpack, full-spectrum warfare B-kit modular armour, the new Cornerstone battlefield management system (CBMS), updated sensors and digital fire control system, increased computing power and storage, new see-through-armour helmet displays, and an electronic countermeasure self-protection jammer to counter radio controlled improvised explosive devices (RCIED).