Challenger 2 LEP bidders downselected; tank to get new turret and new gun?

Two bidders for the life extension programme (LEP) of the British Challenger 2 main battle tank (MBT) have been shortlisted by the UK ministry of defence (MoD). The shortlisted companies will be contracted in the next few weeks for the production of two prototypes worth €25.8 million each. After a 24 month long assessment phase, the final production contract will be made with one of the downselected contenders. In case of unforseen issues, a further €7.8 million can be allocated by the British MoD. Originally the contracts were expected to be signed in October, but the project was apparently delayed, so that currently contracts are expected to be signed in December of 2016. The Challenger 2 LEP is part of the Armour (MBT) 2025 project, which is meant to ensure the Challenger 2 remaining competitive in the timeframe from 2025 to 2035.

After General Dynamics decided to join the Team Challenger 2 lead by BAE Systems, the original predictions from our overview -  suggesting that both BAE Systems and General Dynamics would be awarded separate contracts due to their ties and involvment with the British MoD and industry - were rendered obsolete. While the British MoD shortlisted Team Challenger 2, it also shortlisted the German defence company Rheinmetall. Rheinmetall has teamed up with Supacat, Thales UK and BMT; it is also cooperating with Supacat as part of the LAND 400 phase 2 proposal of the Boxer CRV for the Australian Army.

The British MoD choice effectively eliminated all other biding companies, which were the Belgian CMI Defence (in a team with Ricardo), the German company KMW (teamed up with Pearson Engineering), the Swiss company RUAG and Lockheed-Martin UK, which teamed with the Israeli company Elbit Systems for a last minute offer.

An important new detail about Rheinmetall's offer has been made public by the defence and industry news agency Jane's IHS. The upgrade concept offered by Rheinmetall includes the replacement of the old commander's sight with the Seoss stabilized electro-optical sighting system, which features a third-generation thermal imager, an eyesafe laser rangefinder and a daysight CCD camera. The Seoss is also used on the Boxer CRV and on the MBT Advanced Technology Demonstrator. The SAS 360° situational awareness system is installed on the turret roof, enabling the crew to better observe the tank's surroundings. In case of the renderings from Rheinmetall's Challenger 2 LEP proposal it includes an additional module to work as a laser warning system (LWS).

Rheinmetall's Challenger 2 LEP proposal

Not entierely sure is the status of the gunner's sight and the Pilkington Optronics TOGS-2 thermal imager. The renderings from Rheinmetall still include the armored box of the TOGS-2, which is located ontop of the gun mantlet. If the gunner's sight is replaced, why would the old box ontop of the gun mantlet be kept? On the other hand Rheinmetall's renderings show no opening at the front of the mantlet-mounted box, which makes it impossible to house any sort of optics inside of it. Also the original news article on Rheinmetall's proposal from Jane's IHS spoke of "optronics" (plural), which might imply that the TOGS-2 and gunner's sight will also be replaced. The Challenger 2 LEP proposal also includes the installation of a new fire control system with a modern electronic architecture. It seems very likely that new fully electric gun and turret drives are also part of the upgrade.

The base armor of the the Challenger 2 is not known to have received any upgrades since the tank originally entered service with the British Army in 1998. The canceled Challenger 2 Lethality Improvement Programme (CLIP) included planned upgrades to firepower, observation devices and survivability. It also included the installation and testing of the Rheinmetall L/55 smoothbore gun under the 120 mm Smoothbore Option Technical Demonstrator Programme (SO TDP). This lead to the creation of the Challenger 2 Hybrid Ordnance (CHORD), a gun combining parts of the L30A1 gun and Rheinmetall's L/55, which was meant to reduce logisitics and costs. Aside of the SO TDP, the gun and turret drives should be replaced, the optronics would have been upgraded and the survivability would be enhanced by either installing an active protection system (APS) or by upgrading the tank's armor. The CLIP however was canceled and became part of the Challenger 2 Capability Sustainment Programme (C2 CSP), which itself ended up being canceled due to a lack of funds.

The British Army even considered buying a completely new tank in response to the questionable lethality of the rifled 120 mm L30A1 tank gun against newer Russian tanks such as the T-14 Armata. The L/55 firing the German DM53 round with tungsten penetrator proved to be superior in penetrating different armor targets compared to the L27 CHARM-3 APFSDS of the Challenger 2's L30A1 gun, despite the latter featuring a depleted uranium penetrator. This is a strong advantage speaking together with the larger array of available ammunition - including the latest 120 mm DM11 programmable HE-ABM (high-explosive, air-burst mode) round - for choosing to adopt the L/55 gun without modifications or as CHORD variant.

CHORD smoothbore gun in Germany, 2005, used for static firing tests

Aside of the option to replace the L30A1 rifled gun with it's current 120 mm L/55 smoothbore gun, the German company also offers to remodel or replace the Challenger 2 turret structure. If chosen by the British MoD, this option will also include a new modular armor system, which allows easier replacement of damaged armor modules and faster upgrading of the tank's armor composition and thickness. This step might be required to mount the L/55 smoothbore gun, as the old CLIP prototype was only able to hold six rounds of the larger 120 x 570 mm unitary ammunition used by the German smoothbore gun. The British Army considered remodelling the turret interior as part of the CLIP to be too expensive.
 

Challenger 2 turret structure being manufactured at the Vickers tank plant

What type of armor would be used on the Challenger 2, if the British MoD was willing to pay for the new turret structure from Rheinmetall, is not known. A subsidiary of the German company known as Rheinmetall Chempro is however manufacturing the AMAP composite armor designed by IBD Deisenroth. The AMAP brand includes a wide variety of armor designs, some of which have been used to upgrade the Leopard 2 tanks of Indonesia, Poland and Singapore. It is also used to protect light and medium weight vehicles, such as the Iveco LMV, the Puma IFV and Boxer.

The AMAP armor is offered either as modernization for existing platfroms or as protection for new vehicle designs. It consists of a wider variety of sub-variants, making use of nano-metric steel, nano-ceramics, composite fibre materials and is used as laminated, spaced and non-energetic/explosive reactive armor (NERA or NxRA), depending on application. It seems most likely that Rheinmetall will offer an upgrade of the Challenger 2 featuring AMAP armor.

The weight of the Challenger 2 TES(H) is about 74.95 metric tons

The Challenger 2 was fitted with a comprehensive applique armor kit as urgent operational requirement (UOR) for meeting the protection levels required for the assymetrical combat in Iraq. Being adopted as part of an UOR, the new armor kit was rushed in service. It was an already existing off-the-shelf product, which was available on the market (probably even already tested by the British MoD). The Challenger 2 did not receive a new proper, purpose-made armor kit, which might have been better adopted to the Challenger 2's design, while possibly being lighter and more efficient. As a result of the theater entry standard (TES) armor kits adopted as UOR, the weight of the Challenger 2 up-armored to the latest configuration, known as TES (Herrick) or TES(H), has grown to nearly 75 metric tons - this makes the Challenger 2 probably the heaviest tank currently in service! The Challenger 2 however still features only a 1,200 hp Perkins Condor CV12 engine. 

By using AMAP armor, it might be possible to reduce the weight of the Challenger 2 MBT to less than 70 or even less than 68 tons, while retaining a similar protection level. Nano-ceramics as featured in AMAP provide a weight reduction of more than 40% compared to conventional ceramic armor. The weight savings from nano-metric steel are not as drastic, but reducing the steel mass by 17% (when using nano-metric steel in combination with composite fibre spall liners) can also be impactful. The weight of a Leopard 2 Evolution tank - i.e. a Leopard 2A4 fitted with new AMAP modules - is about 60 metric tons, or about five metric tons more than the Leopard 2A4. The Leopard 2 Evolution upgrade includes a mine-protection kit, additional side armor modules and roof armor, while also featuring the option of using the ADS system to defeat incoming tank and anti-tank ammunition.

Side armor module of the Leopard 2 Evolution defeating a PG-7VLT with tandem warhead

In case of the Leopard 2 Evolution, the side armor of the tank was capable of resisting the PG-7VLT ammunition with tandem warhead, which can penetrate more than 500 mm of steel armor after defeating explosive reactive armor (ERA). In static tests, a similar thick array of AMAP was also capable of protecting against the PG-7VR round (fitted with the same warhead as used by the RPG-29 ammunition), which is capable of penetrating up to 750 mm steel armor (600 mm after ERA). It is not known if the Challenger 2's side-armor - consisting of ERA manufactured by the Israeli company Rafael mounted ontop of a thinner layer of passive armor - is capable of protecting against ammunition with tandem shaped charge warhead arrangements. However even if it is capable of doing so, the advantage of a passive/non-explosive system is a much greater multi-hit capability, leaving less exposed area after protecting against a RPG or an ATGM.

The integration of the German MUSS softkill active protection system (APS) into British combat vehicles is being tested by QinetiQ on behalf of the British MoD.

Given that the Rheinmetall L/55 gun was already adopted in 2001 and the MUSS APS was already successfully tested on the Leopard 2A5 in 2006 - the rather late adoption of the MUSS APS in the actual army service was the result of the delays in the Puma's development, most of which resulted in changed requirements - one has again to wonder about the sense in the Challenger 2 modernization. In the end the tank is meant to remain in service until at least 2035, while the original Challenger 2 configuration was meant to stay active until 2025. The series production of the Challenger 2 LEP is expected to not start before 2020, at this time the L/55 gun will be 19 years old... and it isn't even secured, that Rheinmetall's optional offer will be purchased by the UK MoD. The Team Challenger 2 has more ties to the British industry and government, a factor which never should be overlooked.

France has already decided to upgrade the Leclerc tank. Germany is about to adopt an upgraded version of the Leopard 2A7, which as announced by Rheinmetall will be the first tank to feature the upgraded L/55A1 tank gun, which will increase the performance (range/armor penetration) by 20%. This gun is not known to be offered as part of the Challenger 2 LEP proposal, but it would be a clear and rather simple upgrade path for the future. Both  Germany and France are currently co-developing a next generation tank armed with a 130 mm smoothbore gun called the Main Ground Combat System (MGCS). According to the German defence magazine ESUT, the British MoD has not yet shown any interest in this project.

General Dyamics reveals Griffin technology demonstrator

At the Annual Symposium of the US Army (AUSA) 2016, the US company General Dynamics has presented it's new Griffin light tank technology demonstrator. The Griffin is meant to demonstrate the abilities of General Dynamics to create a modern light/medium tank with technologies that could be utilized on upgrades for existing vehicles. It is apparently aimed at the US Army, but also at the British military, which originally planned to buy a direct-fire support version of the Scout-SV (ASCOD 2).

The Griffin is based on combined technology from the development of the Ajax version of the ASCOD 2, the Engineering Change Proposal (ECP) upgrade suggestion for the M1 Abrams tank and leftover technology from the Future Combat Systems (FCS) program. It is designed to fit two Griffins into a single C-17; the weight of a single vehicle is less than 30 metric tons.

The Griffin uses a tracked chassis, which seems to be based on a composite fibre construction, a technology already tested during the 1980s and 1990s. It has been utilized in certain places on a few combat vehicles such as the K21 infantry fighting vehicle (IFV). The roadwheels and tracks are covered by a rubber flap, which reduces dust creation and can positively affect the thermal signature. The composite construction should reduce the noise generation and provide improved stealth characteristics. Alternatively the Griffin hull might still utilize a steel or aluminium construction and is only covered by some glass-reinforced fibre material for better stealth characteristics. The Griffin's chassis seems to be a modified ASCOD 2 (Ajax) chassis.

The Griffin is armed with either a 105 mm or 120 mm gun. It seems that the prototype might be fitted with a version of the XM360 tank gun. A coaxial machine gun is also fitted, based on the available ammunition it should be either a 5.56 or 7.62 mm machine gun. The Griffin is fitted with "world-class fire control" according to General Dynamics, but it appears to lack an independent commander's sight in it's current iteration. Instead it is only fitted with a gunner's sight apparently based on the M1 Abrams' Gunner Primary Sight (GPS).

An interesting fact of the prototype is, that it has been presented with two types of multipurpose rounds (HEAT and HE), but not with APFSDS ammunition. This might imply that the muzzle break affects the ability to fire APFSDS rounds, but it might just as well be a coincidence.  The APFSDS ammunition was located at the other side of the vehicle and is clearly visible on this and other photographs. The gun can fire anti-tank guided missiles, although the US Army currently has no gun-launched guided missiles in it's inventory.

The Griffin is manned by a crew of four. This means it is not fitted with an autoloader and instead a soldier loads the gun. The commander is provided with a large cupola for better situational awareness. Currently there is no remote weapon station (RWS) and no pintle-mounted machine gun for use against infantry and aircrafts.

As for protection and mobility, General Dynamics' information is currently very limited. The Griffin is capable of adopting an active protection system (APS). Most likely the Griffin is fitted with a MTU engine, Renk transmission and DST tracks (formerly Diehl tracks, but KMW bought the responsible subsidiary from Diehl), which have been used on all other ASCOD chassis designs. 

The ASCOD 2 Direct Fire variant

Given the relatively low weight, the passive armor protection might be limited. The ASCOD 2 Direct Fire version proposed by General Dynamics European Land Systems (GDELS) was fitted with Cockerill CT-CV 105HP turret with 105 mm gun and was expected to weigh some 30 metric tons. While there is a possibility that the steel hull of the ASCOD 2 might have been less weight efficient than the Griffin hull (which might  made from glass-reinforced plastic fibres), the turret (with an autoloader and only STANAG 4569 level 3 or 4 protection) should most likely be more weight-efficient than the Griffin's three-men turret. The ASCOD 2 DF's hull was fitted with composite applique armor for protection against 30 mm APDS/APFSDS from 1,000 metres along the frontal arc (which is actually slightly below STANAG 4569 level 6, which calls for protection from 500 metres distance) and 14.5 mm AP ammunition at the sides. It seems unlikely that the Griffin will exceed this protection level.

Post Scriptum:

CAV via ThinkDefence

The Composite Armoured Vehicle (CAV) and the Composite Armoured Vehicle Platform (ACAVP) of the UK utilized a hull made of glass-reinforced plastic and shows why the Griffin is believed to feature such a hull design. At 24 metric tons it provided all-round protection against 14.5 mm AP and frontal protection against 30 mm AP ammunition.

LAND 400 updates and thoughts

Early in August, Australia announced that the DoD had chosen to shortlist the Boxer CRV and the AMV 35 CRV for the LAND 400 Phase 2 project to replace the outdated ASLAV wheeled fighting vehicle as "Combat Reconnaissance Vehicle" (CRV) of the Australian Army. This effectively eliminated the LAV (CRV) and Sentinel II (Terrex 3 with Elbit MT-30 turret) from the tender. 225 Combat Reconnaissance Vehicles are expected to be purchased by Australia.

The Boxer CRV from Rheinmetall/ARTEC is the high-end solution. It supports the largest gross vehicle weight and is the only vehicle meeting the higher protection level demanded by the Australian Army (STANAG 4569 level 6/6+). It was one of only two candidates offered with an anti-tank guided missile (ATGM) launcher and an active protection system (APS). Compared to the Sentinel II, it's missile launcher is dampened, so that a long-term storage of the missile inside the launcher is possible. It is also the only vehicle that has been fitted with an remote weapon station (RWS) ontop of the turret. The Boxer's Lance turret can be equipped with either a 30 mm or 35 mm autocannon, offering a greater versatility than all other offerings.

The US company Northrop Grumman is responsible for integrating their C4ISR equipment into the Boxer CRV. C4ISR stands for command, control, communications, computers, intelligence, surveillance and reconnaissance. The British Supacat will assure that the Boxer CRV meets the AIC requirements and will help Rheinmetall set up the corresponding facilities in Australia. The Australian industry capability (AIC) requirements for LAND 400 demand local facilities for development, manufacturing and support of the vehicles with a long-term impact on the capabilities of Australia's industry.

The Patria AMV 35 CRV is offered by Patria in cooperation with BAE System. It mounts the E35 turret (from the CV9035) ontop of a Patria AMV chassis. Compared to all offerings it is the most proven solution, combining a combat proven chassis with a combat proven turret. On the downside however the currently known prototypes of the AMV 35 CRV happen to have the least amount of advanced features compared to all other original contenders for LAND 400 Phase 2. It currently has no APS, albeit Rheinmetall's ADS has been fitted to some AMVs for international defence exhibitions. The Ukranian Zaslon APS was proposed in a special lightweight version for the Polish Rosomak (a version of the Patria AMV with the HITFIST turret from Oto Melara). Currently there is not a single type of ATGM launcher available for the E35 turret, the development of such a launcher has to be funded by the Australian Army. The current prototypes seem to lack an remote weapon station. Bofors Lemur RWS was offered on the CV9035 for the Canadian Close Combat Vehicle (CCV) project, but this combination has not been adopted by another country. While different versions of the Combat Vehicle 90 have been fitted with Kongsberg's Protector RWS, this has not been installed on a CV9035 with E35 turret yet.

The biggest benefit of the Patria AMV is that it is supposedly a lot cheaper than the Boxer. Polish-made AMVs have been sold for as low as $1.1 million per vehicle to Slovakia. Meanwhile the Lithuanian Boxer IFVs costs more than €4.4 milion per piece (although the contract probably includes development and support costs).

The Patria AMV 35 CRVshould be considered a cheap, but less capable option compared to the Boxer. The Boxer CRV is the "we put everything possible in the vehicle" solution, while the AMV 35 CRV seems to be based on a more reasonable cost-to-benefit ratio. However, aside of lower armor and lack of advanced features, there are a few more aspects about the proposal from Patria and BAE that are not so ideal. Not offering the latest configuration of the AMV^XP, but an older chassis with only 30 metric tons of payload (still three more than the original 8x8 AMV could handle) is sub-optimal for a vehicle meant to stay in service for several decades to come. The commander's indepent optronics are integrated into the cupola, making hunter-killer options possible, but more cumbersome than utilizing a proper panoramic sight like the Boxer CRV or the Sentinel II. 

Some people are wondering why General Dynamics didn't offer the newer Piranha 5 vehicle instead of the LAV (CRV), which is based on the LAV 6.0 upgrade for the Canadian Army. The LAV 6.0 is based on the old LAV-III fitted with current upgrades including a new suspension.

However supposedly one of the main points of criticism of General Dynamics LAV (CRV) was the unmanned turret: the LAV (CRV) was fitted with the Kongsberg's Protector Medium Calibre Turret 30 (MCT-30), the only pure unmanned turret offered for the LAND 400 Phase 2. An unmanned turret offers reduced situational awareness and lower ergonomics compared to a manned two-men turret. This is very important, because the Protector MCT-30 is the same turret used on most Piranha 5 infantry fighting/scout vehicle prototypes to this day.

In so far there is reason to assume that a hypothetical Piranha 5 CRV also would have been fitted with the MCT-30, when offered to Australia for the LAND 400 Phase 2. So it would have been disliked by the Australian Army aswell. The MCT-30 turret can only be armored up to STANAG 4569 level 4, thus this most likely Piranha 5 CRV configuration still fails to meet the protection level required for the LAND 400 Phase 2.

In general the MCT-30 turret also provides less features than the options offered by Rheinmetall and Elbit/ST Kinetics. While the unmanned turret has been presented on a number of different defence expositions fitted with a single Javelin ATGM without dedicated launcher unit, this is understood to be a mere mock-up and no ready-for-production feature. Furthermore the SAAB LEDS hardkill active protection system has been fitted on soome Piranha 5 prototypes with MCT-30 turret. This APS provides some advantages over the Iron Fist LC system fitted to the Sentinel II (in particular it has three times as much countermeasures in the launchers ready-to-fire), but also comes with it's own unique disadvantages. The launchers are very tall which impacts the ability to travel under bridges and in tunnels, while they also reduce situational awareness by blocking parts of the field of view of turret-mounted sights.

The only manned turret that has been fitted to the Piranha 5 is Rheinmetall's LANCE modular turret system on a prototype for the Canadian Close Combat Vehicle program. This program penultimately resulted in the creation of the LAV 6.0, after the budget for purchasing new vehicles was cut. While there is no actual proof for this, it seems possible to assume that Rheinmetall won't be interested in cooperating with General Dynamics and won't let GD use the Lance turret.

The Steyr SP-30 turret

General Dynamics itself is not producing many turrets suited for the Piranha. While there is the old Delco turret (developed by GM Defence, a company acquired by General Dynamics) used on existing vehicles of the LAV family, this turret is outdated, undergunned and barely protected compared to the Australian requirements. Hence this turret is not suited for LAND 400. Aside of the Declo turret, GM Defence developed a number of other turrets before being acquired by General Dynamics, but none of them ended up being used on a series vehicle.

The only medium calibre manned turret that General Dynamics currently has on offer is the Steyr SP-30 turret of the ASCOD infantry fighting vehicle (IFV). This turret is armed with a 30 mm autocannon (just like the Kongsberg MCT-30 turret) and can be fitted with ceramic armor for protection against 30 mm AP(FS)DS from 1,000 metres (essentially STANAG 4569 level 6 protection, however this standard didn't exist at the time of the SP-30's development). The base turret offers only protection against 14.5 mm API ammunition. However there is a major problem within GD's decision making that rendered this option pretty much impossible: by favoring marketing the existing Piranha family - even the older models - instead of also pushing the slightly more modern Pandur II family of vehicles, together with General Dynamics strategy to encourage local licence-production of the Pandur II (probably done in order to evade the higher wages and taxes in Austria), General Dynamics started the downfall of the Vienna-based Steyr-Daimler-Puch company. With little to no design and manufacturing capabilities for Steyr turrets left (the adoption of the Lance turret for the Scout-SV Ajax says a lot), General Dynamics seems to have pretty much lost capabilities to produce an IFV or CRV based on military-off-the-shelf (MOTS) components on it's own. 

Even if a version of SP-30 was an option for LAND 400, General Dynamics still would suffer from a prominent lack of certain key technologies: the turret has only been fitted with Rheinmetall's MK 30-2 autocannon, which is a gas-powered weapon system - unlike the electrical-driven Mk. 44 Bushmaster II chain gun from Aliant Techsystems. Thus if Rheinmetall decided to not cooperate with General Dynamics, there would be issues as the externally-powered Bushmaster II will require more internal volume. Also the fire control system of the Ulan (the Austrian ASCOD version) relied on thermal imagers supplied by the Israeli company Elbit, which teamed up with ST Kinetics to offer the Sentinel II to Australia. Another blocking options for the competition.

Depending on source the Piranha 5 has a maximum gross vehicle weight of 32 or 33 metric tons, although the original press release from the reveal of this vehicle speaks only of a maximum 30 metric tons. It seems that the higher maximum weight is the result of further improvments to drivetrain and suspension. Back when the Piranha 5 was chosen as the winning bid for the wheeled plattform of the British Future Rapid Effect System (FRES) project, the Piranha 5 version with the IOC (inital operational capability) demanded by the British Army was expected to have a combat weight of 26 metric tons. As the protection requirements of the British Army were less strict and their Piranha 5 version was expected to have a machine-gun-armed RWS instead of a medium calibre turret, it seems overall unlikely that the Piranha 5 chassis can accept STANAG 4569 level 6 armor with a manned turret. The heavier (and newer) Sentinel II wasn't able to meet the demanded STANAG 4569 level 6 protection at a gross vehicle weight of 35 metric tons.

In so far, even if General Dynamics had offered the Piranha 5 chassis and this was considered to be compatible with the MOTS requirements of the Australian Army, it most likely still wouldn't have been chosen. It offers less than the Boxer CRV (protection, firepower, payload, features), but is more expensive and less proven than the AMV 35 CRV. The main difference between a Combat Reconnaissance Vehicle (emphasis on the combat) and a normal scout vehicle is being able to combat enemy units and arm or. Thisrequires protection and a turret armed with a gun capable of punching through opposing forces' armor. If the turret doesn't work as intended or does it's job badly - which apparently was the result of the Australian evaluation of the LAV (CRV)'s MCT-30 turret - the CRV concept will fail.

If a CRV is a concept of sense and reason is another topic, that won't be discussed here yet.

The Sentinel II was also rejected, despite being the second heaviest option after the Boxer CRV. It consisted of a MT30 turret mounted ontop of a Terrex 3, which itself is a Terrex 2 with increased payload. The Terrex 3 chassis  from ST Kinetics and the MT30 turret from Elbit Systems have revealed a number of unique and common shortcomings. Most importantly they are completely unproven at the time of the Australian down-selection, but it also suffers from relatively low protection (not being better armored than the five tonnes lighter Patria AMV with 35 mm gun turret). While the hull's armor can be improved by converting the turret into an unmanned configuration (with reduced protection), it still fails to meet the original LAND 400 Phase 2 requirements for protection. The supposedly poor reception of the Kongsberg MCT-30 unmanned turret also might imply a general dislike of unmanned turrets. This would mean that the Sentinel II was restricted to STANAG 4569 level 4 protection at best. The huge physical size of the Sentinel II, a result of it's Terrex-2 ancesty, meant that more surface needs to be armored, hence the gained protection per added is a bit smaller than on some of the other contenders.

The Sentinel II was meant to be an high-end offering, just like the Boxer CRV. The LAV (CRV) and AMV 35 CRV appear to be more budget oriented offerings, lacking some of the more advanced components for a lower price. Australia's choice of the AMV and Boxer seems to combine the better high-end vehicle with the better budget oriented vehicle, so that the changes to the budget still while deliver a good vehicle; if only the two bidders with the more expensive vehicles had been shortlisted, budget cuts could result in the end of the LAND 400 Phase 2 program. This way however, the most capable vehicle options remain open.

Aside of the aforementioned protection, the Sentinel II suffers from a number of minor and major drawbacks compared to the Boxer CRV, which is why it shouldn't be considerred the better high-end offer. The Sentinel II has no RWS options integrated into the vehicle. It also has only a non-dampened launcher for the Spike ATGMs. A non-dampened launcher does not stop the vibrations of the vehicle from being transported onto the missiles. Such vibrations can damage the the internal guidance electronics and thus prevent longer storage of the missiles in the launcher. Instead the missiles can only be loaden before a mission or during a mission. 

A further issue might be the Iron Fist LC's launcher configuration. The Iron Fist Light Configuration (LC) active protection system is located ontop of the turret and hence increases overall vehicle height, reducing the ability to travel through tunnels and under bridges. This apparently has been a concern for the LAND 400 program, at least Rheinmetall made sure that the commander's sight could be retracted and the RWS folded down, so that the vehicle height when traveling is barely affected by these components. A bigger drawback of Iron Fist LC is however the amount of ready-to-fire countermeasures and launchers. The system has only two launchers, each having two barrels for countermeasures. This means the APS can engage at most two threats at the same time (a simple solution for insurgents and soldiers would be to overpower the APS by attacking with three RPGs or ATGMs at the same time) and has to be reloaden after four engaged RPGs/ATGMs. While at least some versions of Rheinmetall's ADS can defeat EFPs, Iron Fist LC is incapable of doing so.

As reported by Jane's IHS, the Australian Department of Defence (DoD) is giving the two remaining bidders the flexibility to modify their proposals and utilize technology from further companies. The marketing manager of Rafael's land systems division, Yiftach Kleinman, claimed that the DoD might select sub-systems not chosen by any bidder and is confident about Rafael's products having a good chance of being accepted: in particular the Samson Mk. 2 remotely operated turret, the Trophy active protection system and the Spike ATGM would be of Australia's interest.

The Spike ATGM is understood to be favoured by the Australian Army and has already been integrated on both of the CRV prototypes fitted with ATGMs. However it seems extremely unlikely that the other systems from Rafael will be adopted. Trophy does not offer any performance advantages over Rheinmetall's ADS, SAAB's LEDS or the Iron Fist LC system from IMI - in fact the nature of Trophy's countermeasures (using multi-EFP warheads) and the launcher design (one single-countermeasure launcher per vehicle side; a launcher can only rotate by ~200° in the horizontal plane) make it appear considerable worse than all other menionted active protection systems.

The Samson Mark 2 RWS has been chosen by the Lithuanian Army for integration into their future Boxers. With Samson Mk 2 RWS the vehicle is called "Vilkas", Lithuanian for "wolf". However aside of having the same "unmanned" issues as found by the Australians on the LAV (CRV) with the Kongsberg Protector MCT-30 turret, the Samson Mark 2 RWS also suffers from poor armor protection and lower features compared to pretty much all other mentioned products. It is understood that the Lithuanian choice of the Samson Mk.2 RWS was the result of reducing the price of the vehicle, as they previously had tested the more expensive (and more capable) Boxer IFV with Puma turret. The Samson Mk. 2 turret can be at most armored up to STANAG 4569 level 4 and thus fails to meet the Australian requirements. It has the same type of non-dampened launcher as installed in Elbit's MT30 turret, but lacks it's laser warning system. There are no smoke grenade dischargers and there is no option for a MG armed RWS ontop of the turret. No APS has been integrated on the Samson Mark 2 turret.

Challenger 2 upgrade proposals have been submitted

As reported by Jane's IHS, MilTechMag and DefenseNews.com, the offers for the Challenger 2 Life Extension Programme (LEP) have been submitted by the industry to the British Army. The Challenger 2 LEP aims at upgrading the Challenger 2 main battle tank (MBT) to a more modern standard, so that it is competitive in the year 2025 and beyond (currently the CR2 is expected to remain in service until at least 2035). The official name for this project is "Armour (MBT) 2025". Meanwhile Germany and France are developing a next generation tank with a 130 mm tank gun and keep upgrading their existing Leopard 2 and Leclerc MBTs.

Originally a total of seven major American and European defence companies have answered the British request for upgrade proposals for the CR2. However the US-based General Dynamics (the manufacturer of the current M1 Abrams MBT) has decided to join the Team Challenger 2 lead by BAE Systems. BAE Systems acquired Vickers Defence Systems, the manufacturer of the Challenger 2 tank. The British MoD is planning to shortlist two bidders in 2016. On request of one unnamed bidder, the deadline for submitting the proposal has been moved by one month and the program was thus delayed. With the delay, the tender response date was moved the 11th August, after this the two most promising bids will be selected in the next weeks. Two contracts of £19 million (€22 million) are expected to be signed with the favoured bidders by end of October. In total the contract for upgrading of up to 227 CR2 tanks is expected to have a worth of up to £624 million (currently €722 million).

In a different contract the UK Ministry of Defence (MoD) has decided to let QinetiQ evaluate the German MUSS softkill active protection system (APS) for integration into the Challenger 2 tank and other British fighting vehicles. A decision to adopt a softkill APS on the Challenger 2 is scheduled for April 2018.

The German company Rheinmetall has made a few aspects of their initial upgrade proposal known in a press release. The company suggest not only replacing outdated components, but also enhance the tank's capabilities further. Upgrades to mobility and protection are further options. Rheinmetall has partnered with the British companies Supacat, Thales UK and BMT.

Seoss sight of the MBT Advanced Technology Demonstrator

The press release included a rendering of an upgraded Challenger 2 tank. The commander's main sight has been replaced by the Seoss stabilized electro-optical sighting system from Rheinmetall. This stabilized optronics include a dual-axis stabilized sensor head with a third generation SAPHIR thermal imager, a laser-rangefinder and a high resolution CCD camera. It is also fitted with an integrated fire control system. The Seoss sight enables a high accuracy even when the tank is moving against static and moving targets. The same sight system has been used on the MBT Revolution/Advanced Technology Demonstrator and on the Boxer CRV. It can be fitted with the Main Sensor Slaved Armament (MSSA) remote weapon station.

It is not clear if the gunner's primary sight has also been replaced with a version of the Seoss sight or the original Gunner's Primary Sight (GPS) from Pilkington Optronics (nowadays part of Thales UK) has been kept. The rendering still shows a distinctive box ontop of the gun mantlet, which used to house the Thermal Observation and Gunnery Sight 2 (TOGS-2) on the original Challenger 2. This might imply that the TOGS-2 thermal sight was kept or upgraded, instead of being replaced by a single sight unit with integrated thermal imager. The rendering however does not show a flap in the armored box; it is not known wether this is result of the 3D model being poor or the TOGS-2 was actually replaced. 

A SAS module below a ROSY smoke grenade discharger

One single unit of Rheinmetall's Situational Awareness System (SAS) can be seen ontop of the turret. Most likely there are two or more SAS units, enough to provide a full 360° sensor coverage. Each unit contains three high definition sights (either day sight CCD cameras or uncooled thermal imagers), each set at 45° angle apart of eachother. Two SAS modules are required to provide a full 360° coverage of the surroundings either at day or night, four for a 360° sensor coverage with cameras and thermal imagers at the same time. The system is designed for easy integration in existing system thanks to an open architecture. It also features an automated warning system, which can be triggered by moving objects when enabled. Optional features of the SAS include automated mission recording, tracking and tracing, a sniper warning system (not installed in the rendering), laser warners (apparently installed) and the integration of SAS into existing fire control and battlefield management systems.  

Rheinmetall also offers the replacement of the outdated rifled Royal Ordnance L30 gun with it's current L/55 smoothbore gun with enhanced armor penetration. This gun would also enable the tank to fire programmable ammunition. 

Elbit Systems' COAPS commander's sight

Lockheed Martin UK has partnered with the Israeli company Elbit Systems for the Challenger 2 LEP. According to DefenseNews, this partnership was established just 24 hours before the deadline for the industry proposals. This is probably the result of Lockheed Martin's partner for upgrading the Warrior MICV, Thales UK, partnering with Rheinmetall. Given that Lockheed Martin's own technological portfolio, as previously noted, is the smallest of all bidding companies, they were forced to find a new partner.

Most likely the proposal from LM and Elbit will include the replacement of the sights with new models made by Elbit Systems. Most likely the commander's sight will be replaced by the Commander Open Architecture Panoramic Sight (COAPS) sight used on the Sentinel II and the TAM upgrade. This dual-axis stabilized sight includes a day sight CCD camera, a laser rangefinder and a latest generation thermal imager. The Pilkington Optronics Gunner's Primary Sight might be replaced with a similar device from Elbit Systems, possibly incorporating a thermal imager and thus allowing the removal of the gun-mounted TOGS-2 sight. Possible upgrade options include the Knight FCS (Elbit's FCS developed for the Merkava tanks) aswell as the Thermal Imaging Fire Control System (TIFCS), which Elbit developed as an upgrade option for existing vehicles.

Laser warning system from Elbit

Given that the last two international land vehicle projects from Elbit Systems included the adoption of a laser warning system, the Challenger 2 LEP proposal from Lockheed Martin UK and Elbit might aswell include the adoption of this system.

Earlier already CMI Defence announced their cooperation with the British company Ricardo UK. While CMI has experience with the manufacturing and upgrading of turret systems, Ricardo is one of the leading British companies in automotive and systems engineering. It is understood that this results in a separation of tasks: CMI Defence is responsible for upgrading the turret, while the hull is being upgraded by Ricardo UK. The latter company has been working with the Defence Science and Technology Laboratory (DSTL) of the British Ministry of Defence on optimizing the drive- and powertrain of the Challenger 2 as part of obsolecence management studies. Ricardo has developed a tool set for accessing the effectiveness and costs of upgrades.

Not much details about CMI Defence's and Ricardo's proposal are known. It might include the adoption of the RUAG-designed Compact Tank Gun (CTG), for which CMI Defence has acquired a licence; however exact details on this licence are unkown and RUAG may be the only company offering said gun for the CR2 upgrade. CMI press releases for earlier products speak of a 120 mm smoothbore Cockerill high-pressure gun; if this is the name for the licence-made CTG or refering to another product has to be clarified.

Most likely the two companies will suggest replacing the sights and electronics, while also adding a new APU or upgrading the powerpack or drivetrain of the tank. CMI Defence has used optronics from different companies for their medium and large calibre turrets, but some of their latest products utilize sights from French manufacturer Safran. However Safran is cooperating with BAE Systems.

General Dynamics and BAE Systems have formed Team Challenger 2, while RUAG announced to cooperate with a group of UK-based industrial partners. The German company Krauss-Maffei Wegmann (KMW), the Leopard 2 manufacturer, has released no details of their upgrade proposal to the public yet, but it appears likely that KMW will rely on optronics supplied by Airbus Defence and Space (formerly Cassidian), which were also used on the current iterations of the Leopard 2 MBT and the Puma infantry fighting vehicle (IFV).

Pound Sterling loosing worth, image by Stratfor

Given the BREXIT, there still should be a big question mark wether the Challenger 2 Life Extension Programme will be futile. The negative impact on the UK economy is currently undeniable, despite the actual BREXIT still being a problem for the future. The British Army is already running other expensive modernization programs such as the procurement of the Scout SV (including the turreted AJAX variant), which is heavily relying on technology and components supplied by EU-based companies, and is also looking to acquire an 8x8 wheeled mechanized infantry vehicle (MIV). Pretty much all candidates rumored for the MIV are European products, which will be more likely affected by the BREXIT than other military procurements.

LAND 400 Phase 2 and 3 contenders update

The Australian Army is currently looking for replacements of the ASLAV and M113AS4 armored fighting vehicles (AFVs).

Phase 2 of the LAND 400 program seeks a replacment for the 13.2 tonnes ASLAV. The ASLAV is used by the Australian Army as scout vehicle, armored personnel carrier (APC), command vehicle, armored ambulance and also as support vehicle. It is either armed with a 25 mm Bushmaster chain gun (in case of the ASLAV-25 scout vehicle) or with a heavy machine gun on a pintle mount or on a Kongsberg remote weapon station (RWS). It transports up to either six or seven soldiers depending on version. Unlike current American and Canadian LAV versions, the ASLAV is only protected by thin steel armor providing protection according to STANAG standard 4569 level two or three.

Currently there are four contenders to replace the ASLAV: The AMV 35 CRV from Patria and BAE Systems, the LAV (CRV) from General Dynamics, the Sentinel II from Elbit and ST Kinetics and the Boxer CRV from Artec (a joint-venture between Rheinmetall and KMW). Originally more contenders including Raytheon and Nexter (offering the VBCI with French T40 turret) were looking for a LAND 400 Phase 2 contract; after considering their chances of meeting the Australian requirements - in particalur the military-off-the-shelf (MOTS) requirements - they withdrew.

While the offer from Patria and BAE Systems - consisting of a Patria AMV fitted with the E35 turret of the CV9035 - was known very well for the past weeks, a lot of new details have emerged on the other contenders. Supposedly Patria isn't offering the latest AMV^XP with increased payload and performance, but the a version of the original AMV hull with higher compliance with the MOTS requirements.

As far as the other contenders are concerned, first and foremost of there is the LAV (CRV), a version of the Canadian LAV 6.0 upgrade modified to meet the Australian requirements. The LAV 6.0 itself is a modified and upgraded version of the old LAV III infantry fighting and scout vehicle.

The LAV (CRV) has the lowest gross vehicle weight of all contenders, sitting at just 28,600 kg. It is fitted with the unmanned MCT-30 turret from the Norwegian company Kongsberg. It features 8 smoke grenade dischargers (in 4 banks of 2 each), the Mk 44 Bushmaster II gun chambered in the 30 x 173 mm caliber from Aliant Techsystems (ATK), a low-profile version of the CROWS RWS and a laser warning system. An interesting side note is that the MCT-30 turret is fitted with the WAO sight from Airbus Defence, which is also used on the German Puma IFV. The US Army prefered to use a different - supposedly cheaper - sight unit for their Stryker upgrade with the MCT-30 turret. The fully stabilized WAO includes a daylight camera, a thermal imager and an eyesafe laser rangefinder.

The LAV (CRV) is also fitted with a 360° surveillance system consisting of three cameras. One is mounted on a mast above the rear ramp, while the other two are located on the frontal hull section. It uses a double-V hull desgin (like the late generation Stryker ICVs of the US Army) for advanced protection against mines and IEDs. For ballsitic protection the LAV (CRV) is fitted with ceramic composite armor on top of it's steel hull. However the ballistic protection of the LAV (CRV) is not able to keep up with the competition, offering only protection according to STANAG 4569 level 4 (all-round protection against 14.5 mm armor-piercing ammunition from 200 metres distance) on the hull. The turret is even less armored, not able to meet the level 4 requirements. According to General Dynamics the vehicle can be fitted with special deployment kits for increased ballistic protections, but this is expected to negatively affect mobility and payload, thus taking away the plattforms growth potential.

The Sentinel II has been a mysterium for quite a while, but ST Kinetics and Israeli company Elbit Systems have showcased their vehicle solution to the public for the first time. It is based on the current Terrex 3 vehiclee from ST Kinetics, but numerous technologies and components from Elbit and it's partners have been utilized. Frankly, due to the Terrex 3 being originally designed for high performance on water during amphibious operation, which are not possible with the heavier Sentinel II. The Sentinel II is fitted with the MT 30 (Manned Turret 30) from Elbit. This turret can be used in either manned or unmanned configuration and is equipped with a 30 mm Bushmaster II chain gun, a co-axial machine gun and a pop-out dual-launcher for Spike ATGMs. Like all other candidates, the vehicle is fitted with a digitial fire control system and stabilized gun to enable accurate firing on the move. The commander is provided with Elbit's COAPS (Commander Open Architecture Panoramic Sight), which includes a thermal imager, a CCD camera and a laser rangefinder. The gunner is provided with a similar set of optronics.Two banks of four smoke grenade dischargers are mounted on either side of the main gun.

Ontop of the turret two launchers of the new Iron Fist LC (Light Configuration) from IMI. This active protection system (APS) was first presented at Eurosatory 2016 and is a scaled down version of IMI's already existing Iron Fist APS. It launches a high explosive (HE) grenade onto an incoming threat that has been spotted by the radar. While the original version of Iron Fist has some anti-APFSDS capability (when the HE warhead fuzes at the right time, it can cause the APFSDS to tilt), the light configuration uses smaller warheads that are most likely inable to affect APFSDS. With only four interceptors ready for defeating RPGs and ATGMs, the Iron Fist LC is not suited for longer engagements, but is a useful asset in assymetrical warfare.

At the front and the rear of the turret a total of four laser warners are installed. These can detect when the vehicle is lazed by a rangefinder or beam-riding missile and may be connected to the APS or the smoke grenade dischargers.

A camera system located at the hull provides 360° close-range vision of the near terrain. The implementation is quite reminiscent of Rheinmetall's SAS 360° system, which has been installed on the Boxer CRV and other vehicles such as the Advanced Technology Demonstrator tank. It consists of three sets of each three cameras, that are set at different angles. On the rear there are only two cameras, while a further camera is located at the frontal hull - these cameras are possibly meant for the driver only.

Like the LAV(CRV) the Sentinel II fails to meet the original Australian requirements for ballistic protection. It only reaches STANAG 4569 level 4, depsite being the second-heaviest candidate for the phase 2 of the LAND 400 program. This is the result of the huge overall dimensions of the Terrex 3 hull, on which the Sentinel II is based. In fact the Sentinel II is the widest and tallest

While it is possible to boost the protection level to the levels protect against 25 mm and 30 mm ammunitions, this is only possible at certain, limited areas and not along the whole frontal arc like required by STANAG 4569. Furthermore this requires to reconfigure the turret into an unmanned configurations and reduce it's armor protection to STANAG 4569 level 2 only - which means being vulnerable to 7.62 x 51 mm NATO AP ammunition or equivalent and larger calibers. A designated marksman rifle or battle rifle would be enought to penetrate the armor and potentially knocking out the Sentinel II's weapon systems by damaging the fire control system, ammunition feed system or turret drives. Due to being designed as a manned turret, the MT 30 is not optimized for unmanned operations and wastes a lot of space and thus valuable weight, that could have been used for increasing the protection.

Overall the Sentinel II has three major drawbacks. The lackluster armor protection does not manage to meet the Australian requirements. Also the missile launcher is not decoupled, so that vibrations will be passed onto the missiles. On the long term this will cause issues as the missile can be damaged or rendered completely used in a not decoupled launcher, so the Spike ATGMs in Eblit's MT 30 turret would need to be stored at other places and only be fitted into the launcher before going to battle/on a mission.

The biggest problem of the Sentinel II is that it seem to completely fail the military off the shelf of the Australian Army. It seems to be an agglomeration of unproven and new parts: the hull is taken from the new Terrex 3, which is still unproven and not in service with any nation. The turret is a new design that has yet to be used on a series produced vehicle. Even the large version of the Iron Fist APS has yet to be fielded on a tank or any other type of vehicle - the brand new Iron Fist LC version is even more of a risk. Arguably the only proven systems are the laser warners, the COAPS sights (which have been chosen for the Argentinian TAM upgrade), the smoke grenade launchers and the Bushmaster chain gun.

Previously some basic infromations on the Boxer CRV have been written here aswell, thus only the newest developments seem to be worth mentioning. Photographs of a Boxer CRV with new features have been published on the internet. The Boxer has been fitted with a version of the ADS (Active Defence System), formerly known as AMAP-ADS. In the configuration as used on the Boxer CRV it includes at least 26 sensor units (maybe even more if the rear is also protected by ADS). Unfortunately this version of ADS appears to be incorporated into the additional armor modules on the side of the vehicle, which doesn't allow accurate counting of the exact number of ADS countermeasures; usually there is at least one countermeasure per sensor unit, in some cases even two.
ADS is capable of intercepting RPGs and ATGMs in all known versions, while the heavier versions are also capable of defeating explosively formed penetrators (EFPs) and large caliber APFSDS ammunition. With an estimated 26 countermeasures, the ADS on the Boxer CRV is much better suited for longer combat operations than the Sentinel II with it's Iron Fist LC APS, however restocking the ADS might take longer.

The Boxer CRV also has been fitted with a dual launcher for Spike ATGMs, which is in contrast to the Sentinel II's launcher decoupled and allows long-time storage of the missiles directly in the launcher.

A new RWS fitted with a 12.7 mm M2 Browning heavy machine gun is located on top of the turret. Unlike most other types of RWS, this specific one does not have an own set of optics, but is rather slaved to the commander's periscope located on top of the turret. Such a weapon station design design was used on some other vehicles already, most noticable the Russian T-90MS main battle tank. Rheinmetall calls this a "killer-killer" functionality (in contrast to the hunter-killer functionality) and claims that this an unique feature of the Lance MTS among medium calibre turret thanks to the so called "Main Sensor Slaved Armament" (MSSA) technology. Most likely the RWS can be folded down, otherwise putting it on the Boxer CRV turret wouldn't make much sense, as the commander's sight was specifically modified to be retractable in order to reduce the overall height of the vehicle.

A rather curios move was made by Rheinmetall for the Phase 3 offering. The vehicle purchased under the phase 3 of the LAND 400 project is meant to be the replacement for the M113 variants in service with the Australian Army, most notably the  While it already is part of the PSM joint-venture offering the German Puma IFV for LAND 400 Phase 3, the German company has decided to make another offer with the Lynx. While Rheinmetall representatives and websites have tried their best to describe the vehicle as a new development and kept their lips sealed on the true nature of the Lynx, it is understood that this vehicle is just a heavily upgraded Marder IFV. A company now owned by Rheinmetall originally build the Marder, several hundred Marders were bought back by the industry and saved from scrapping.

The suggested APC version of the Lynx is fitted with a RWS and the ROSY smoke protection system

The Lynx is fitted with the same Lance MTS (modular turret system) turret as the Boxer CRV, however with slightly different armament. While it also includes a decoupled twin-launcher for Spike ATGMs, it was presented with a larger 35 mm autocannon as main gun and Rheinmetall's three-barreled RMG 7.62 machine gun. Unlike a gatling gun the latter weapon is fitted with three barrels to reduce barrel wear and it is possible to switch to another barrel within less than 5 seconds. Rheinmetall claims that this enables the user to switch to a cold barrel in the middle of combat, which leads to a higher accuracy and sustained rate of fire. The Lynx is fitted with Liebherr engine (depending on versio delivering either 750 hp or 1,050 hp), segmented rubber tracks from DST and a NBC protection. Iversionst's armor seems to be largely identical to the late version Marder IFV (1A3 and follow-up ), which utilized spaced steel armor for ballistic protection against up to 30 mm rounds. The side armor of the Lynx appears to be different, the spaced armor and storage boxes of the original Marder 1A3 were replaced by plates of steel or composite armor. The ADS has not been fitted, but according to Rheinmetall it is an option.

The armored recovery version of the Lynx vehicle is fitted with a crane

An interesting suggestion is creating two versions of the Lynx, one of them utilizing a stretched chassis. While as previously noted all existing offers for the Phase 3 have only a 3 + 7 configuration (assuming realistic amounts of internal storage space), the Lynx is offered as KF 31 and KF 41; the latter has a sligthly strechted hull (but the same number of roadwheels) to provide seating for a crew of three and up to eight dismounts, while the shorteer KF 31 has is designed for only six dismounts. Aside of the lower price compared to more expensive offerings such as the Puma IFV, this might be the main selling point of the Lynx IFV.

In general Rheinmetall claims that the Lynx armored vehicle family is making use of a modular approach - how modular this is exactly is not known yet. While the description from Rheinmetall - speaking of separate Base Vehicles and Mission Kits- is suggesting a concept similar to the Boxer, the Lynx doesn't appear to be compatible with Boxer mission modules. It also remains questionable if it is possible to change the mission kit of a Lynx during it's lifetime without major factory-based (re)work. The Lynx will be offered as turreted and non-turreted version for the different roles of the vehicles replaced under LAND 400 Phase 3.

Informations on LAND 400 Phase 3 candidates

The Australian Defence Technology Review has published an interesting article on the third phase of the LAND 400 program of the Australian Army. The LAND 400 program is the planned replacement of the currently outdated equipment of the Australian forces - such as the ASLAV and the M113 - with modern state-of-the-art vehicles.

Part of the phase 3 is the procurement of a planned 450 medium-weight tracked vehicles, of which 312 will be fitted with a turret in an infantry fighting vehicle (IFV) configuration.
As of today, three contenders for this contract are known: The German company PSM (a joint venture of Rheinmetall and KMW) will offer their Puma IFV, BAE Systems is reportedly offering the CV9035 and General Dynamics is supposedly offering a vehicle based on the ASCOD 2.
The Puma is one of the latest IFVs, with the first Puma entering service in June 2015. It's probably the heaviest armored IFV available on the market and is fitted with a number of advanced features like a decoupled running gear with hydropneumatic suspension, third generation thermals, a softkill active protection system (APS) and a modern fire control system (FCS) with independent commander's sight. The Puma will be armed with a 30 mm MK-30/2 ABM autocannon with athe ability to fire airburst ammunition, a coaxial machine gun, a dual-purpose Spike-LR ATGM launcher and an independent grenade launcher mounted on an elevatable mast. The Puma has not been fitted with an remote weapon station (RWS) yet.
It is powered by a 10 cylinders MTU MT892 engine which is fitted in combination with a version of the HSWL 256 transmission from Renk. It provides an output of 800 kW.

The Puma IFV is the newest vehicle competing for LAND 400

It seems to be rather clear that the Puma should be able to fullfill all armor and protection requirements, given it's weight, the German requirements and the extensive amounts of armor.
Problems for the Puma are at least the lack of a turretless version for the non-IFV version, the rather huge price tag and the lower troop carrying capacity.

The ASCOD 2 is based on the development of the Ulan (pictured) and Pizarro IFV

Which version of the ASCOD 2 might be offered to Australia is unkown yet. The latest vehicle based on the ASCOD 2 is the British Army's Ajax, which will utilize the CTAS (case telescoped armament system) 40 mm gun (but the Ajax is not an IFV and transports no dismounts). The CTAS gun offers more punch than the 30 and 35 mm autocannons of the  Puma and CV90, but suffers from lacking commonality with the planned 8x8 vehicle (for this GD offers the LAV 6.0 with 30 mm Kongsberg unmanned turret). Thus the ASCOD 2 version for the Australia is expected to be offered with a 30 mm Bushmaster II gun mounted in either a manned or unmanned turret. The early ASCOD 2 prototypes utilized the same SP-30 turret as the Ulan of Austria and the Pizarro of Spain, the original ASCOD 1 versions. This turret is manned by a crew of two and mounts a MK-30/2 autocannon from Rheinmetall, the previous version of the Puma's gun. While the Ulan and the Pizarro have been fitted with different fire control system, it seems that none of this is hunter-killer capable, despite both providing separated sights for the gunner and commander. These two FCS (made by Kollsman/Elbit and Indra respectively) are the only known to be fitted to the SP-30 turret. The ASCOD 2 utilizes the MTU V8 199T21 engine, which provides an output of 600 kW (about 800 hp). The engine is used in combination with the HSWL 256B transmission from German company Renk.

An ASCOD 2 APC presented on Eurosatory 2014

However the original ASCOD design is lackluster at a few other places. Except for the current Scout-SV vehicles, such as the Ajax revealed last year at DSEI 2015, the ASCOD lacks a high performance anti-mine kit and heavy armor solutions. The basic ASCOD 2 is protected against 14.5 mm AP ammunition in accordance with STANAG 4569 level 4, although even the old flyers from several years ago mention the possibility of up-armoring the ASCOD 2 to level 5 (protection against 25 mm ammunition allong the frontal arc). No version of the ASCOD 2 has been presented with an RWS ontop of the turret, but a special APC version with RWS has been produced. The ASCOD 2 might also have issues with the 8-men squad requirement from the Australian Army - while the Ulan can carry 8 soldiers, the Pizarro (due to different interior arrangement and troop equipment) transports only a 7-men squad. The ASCOD 2 utilizes most likely decoupled mine-safe seats (like the Puma) and proper decoupled equipment storage, which makes it rather improbable that without deeper modifications an 8-men squad can be transported. Unlike the Puma, the ASCOD 2 will probably not offer an integrated ATGM without extra costs.

A CV9035 of the Koninklijke Landmacht

The Combat Vehicle 90 Mark III (CV9035) is the most proven of the three vehicles, being in service in the Netherlands, Denmark and was recently ordered by Estonia. The CV9035 uses the E35 turret armed with a 35 mm Bushmaster III gun from ATK. The same turret is also offered for the Patria AMV35 and thus the CV9035 would offer a great benefit in terms of commonization of parts and spares, if the AMV35 is chosen over it's competitors.
The CV 90 Mk. III is powered by a Scania V8 engine with an output of 600 kW. The basic vehicle is constructed from steel, providing protection against 14.5 mm AP and 23 mm API along the frontal arc. However like the ASCOD 2, the CV9035 is pretty much always fitted with applique armor to boost the protection level to STANAG 4569 level 4 and/or level 5 at least. Further armor kits and mine-protection kits for the CV9030 and CV9040 have been developed, it seems reasonable to assume that those armor kits can be modified to CV9035 compatability. While BAE's brochures claim that the CV90 has hunter-killer capability, it seems that this is dependent on the exact FCS version fitted, which differs depending on user's configuration.

The Armadillo APC is a turretless CV90

A turretless version of the CV90 is already existing with the Armadillo APC. Unlike the ASCOD 2 and the Puma, there is at least a version of the CV9030 fitted with an RWS ontop of the turret; the possibility of adopting the same to the CV9035 seems to be given. 
The CV9035 however is also the oldest designs and suffers from more drawbacks. Like the ASCOD 2, the CV9035 lacks an ATGM armament for fighting heavier armored targets and/or helicopters. While the 35 x 228 mm caliber of the Bushmaster III gun packs about 50% more punch than a 30 x 173 mm round of the MK-30, it's much larger physical size has a very negative impact on ammunition stowage. While the Puma and ASCOD 2 (with SP-30 turret) both can carry 200 rounds loaden at the gun, the CV9035 has only 70 rounds available at the gun. The total ammunition stowage is also much lower. Furthermore the CV9035 is also not able to meet the 8-men dismount squad requirement of the Australian Army in it's current configuration deployed by the Dutch and Danish armies.
Lastly the ballistic and mine protection of the CV9035 seems to be relatively low compared to that of the Puma and ASCOD 2. While armor packages are available, these might need additional reconfiguration to the exact CV9035 layout and

It is interesting what currently seems to be happening in the SEA region. Australia is planning to acquire huge numbers of state-of-the-art wheeled and tracked vehicles, while many NATO countries including the US have to cut back most of their military procurment plans due to funding issues. There are a number of issues and unkown factors with the Austrlian LAND 400 program still: We don't know if other contenders will or already have responded to the tender for the tracked vehicle aswell. Currently we only know that the Puma - apparently most likely in the standard German Army configuration - the ASCOD 2 in an unkown configuration and the CV9035 in a somewhat unkown configuration will compete for the contract. All three of the previous mentioned vehicles might have trouble with the Australian Army's requirement for transporting a 8 men squad of dismounts and have other individual issues each. From my point of view the Puma might be the best bet, but also the most expensive. In terms of protection, technology and the armament concept (once the integration of the Spike-LR and the grenade launcher are finished) seems to be the most promising. The lack of ATGM armament on the other vehicles would be a no-go for me, but we don't know what GD and BAE will change for Australia. But who knows what the Aussies want, in the end they happen to have one of the most scatterbrained and odd mechanized infantry concept out there.
The LAND 400 phase 2 will probably already be a preliminary decision, it seems likely that the winner of one contract will have a huge benefit in the other due to the ability of keeping parts exchangeable and cutting costs down.

CR2 upgrade contenders

According to Jane's IHS, several contenders are in the run for the Challenger 2 LEP upgrade contract.

The contenders that send bids to the UK Defence Equipment and Support (DE&S) are:

• BAE Systems Combat Vehicles
• General Dynamics Land Systems UK
• Lockheed Martin UK
• Krauss-Maffei Wegmann
• Rheinmetall
• CMI Defence
• RUAG Defence

The Challenger 2 life extension programme (LEP) was announced some time after the reveal of the T-14 Armata tank in Russia during the Moscow Victory Day Parade 2015. At first the UK MoD also considered buying a completely new main battle tank (MBT) as replacement of the Challenger 2. In particular the lethality and the effectivity of the L30A1 tank gun has been questioned.
Unlike other tanks such as the M1 Abrams and the Leopard 2 MBTs, the Challenger 2 has not seen any major upgrades since it's introduction into British Army service in the 1990s. The British Army already investigated the replacement of the rifled L30 gun with a German Rh 120 L/55 smoothbore gun during the Challenger 2 lethality improvment programme (CLIP) beginning in 2001, but this project was terminated due to too high costs. The German gun together with the superior tungsten ammunition proved to be more effective during the British trials.
The follow-up to CLIP was the Challenger 2 capability sustainment programme (C2 CSP), which incorporated most parts of the CLIP and some new upgrade ideas. However the C2 CSP also ended up being too expensive and was thus terminated in 2008.
The Challenger 2 LEP was announced in July 2013 and started one year later. The reveal of the T-14 Armata however triggered however the UK's interest in owning a tank strong enough to cope with the T-14.

The Challenger 2E is the most advanced version of the CR2 to be developed by Vickers/BAE yet.

The list of contenders is rather interesting. BAE as owner of Vickers has the in-house advantage, but has not gathered any experience in modern tank design/building since the Challenger 2. Even worse BAE had to rely on the purchased Hägglunds for any sort of the success on the AFV export market in the recent history. In theory BAE might fall back to the old Vickers Challenger 2E tank designed for export, which failed to perform equally well as the Leopard 2, Leclerc and M1 Abrams in the Greek trials in the early-2000s. The Challenger 2E offers a number of considerable upgrades over the current CR2: a EuroPowerPack (MTU MT883 engine together with Renk HSWL 295TM transmission) and a new, superior fire control system with the SAGEM MVS 580 periscope and SAGEM SAVAN 15 gunner's sight. However BAE announced in 2005 that the development of the CR2E was stopped following lack of success on the export market.

General Dynamics is having the Abrams as up-to-date modernized MBT. While the upgrades might not be as deep as the ones offered by other companies on the market, this seems to be largely related to the lack of funding from the US and the low interest in upgrading foreign M1 Abrams tanks (due to the fact that most Abrams user's like Egypt, Iraq and Australia do not have the money for any tank upgrades).
For the Scout-SV programme General Dynamics European Land Systems however had to rely quite a bit on other companies from this list: the turret for the Ajax is based on Rheinmetall's Lance Modular Turret System and at least partly manufactured in Germany, whereas Lockheed Martin UK has developed the fire control and reconnaissance systems for the Ajax.

The upgraded Warrior using Rheinmetall's turret design as base is the best reference that LM can offer.

Lockheed Martin plays a major in the Warrior capability sustainment programme (WCSP) and in the Ajax variant of the Scout-SV, but lacks any own vehicle designs. Instead LM mostly upgrades electronics and other sub-components of AFVs mostly. For the Scout-SV and the WCSP Lockheed Martin relied on turret technology supplied by Rheinmetall and technology/components supplied by other sub-contractors.

Krauss-Maffei Wegmann (KMW) is currently the world market leader when it comes to tanks and thus should be considered a very safe bet. While on pure numbers the M1 Abrams and the T-90 have sold more units, this is often the case by allowing the local assembly of cheap, downgraded and subsidized versions (such as the M1A1 tanks for Egypt or Iraq and the T-90S tanks for India). KMW has shown the willingness to create local versions of the Leopard 2 and to allow local assembly. They also have shown intention to upgrade designs made by other companies (such as their bid to upgrade the Brazilian M113s). During the 1980s and early 1990s KMW developed a special tank based on the Leopard 2 tank for the Spanish Army. KMW could just as well "leopardize" the Challenger 2 by fitting the Challenger 2 with as many proven sub-system of  the Leopard 2 as possible.

Rheinmetall has seen increased success on the tank market, after starting to compete against KMW for Leopard 2 upgrades in 2010. They just recently managed to win a contract for the modernization of the Polish Leopard 2A4 tanks to a new Leopard 2PL standard. Rheinmetall has a wider variety of subsidaries and can probably, unlike pretty much any other contender, provide most technologies and components by themselves, without the need to hire a subcontractor.
With the MBT Revolution upgrade, Rheinmetall does already offer a modular upgrade which in theory is designed to fit (with some adaption) to any tank. So maybe we can see some type of Challenger 2 Revolution?

Leopard 2 Revolution prototype - will the CR2 soon look similar to this?

CMI Defence is probably the least expected candidate for the Challenger 2 LEP tender. It never has produced or designed a complete AFV or even a major AFV upgrade. Instead CMI Defence is specialized on light-weight medium/large caliber guns (such as the series of Cockerill 90 mm guns or the Cockerill CV 105 gun) and making ammunition for these. However in the past years CMI has extended it's portfolio into the market of turrets and weapon stations.

CMI's biggest turret on a CV90

RUAG Defence of Switzerland has experience with the modernization of medium and heavy combat vehicles for the Swiss Army and several other export costumers. The Panzer 87WE upgrade for the Swiss Army was developed in cooperation with KMW, previously RUAG also upgraded the Swiss fleet of M109 howitzer. Other tank modernizations from RUAG include upgrades for the older Panzer 68 and cooperation with Jordan on the M60 Phoenix MBT prototype. In 2015 RUAG has managed to win a contract for upgrading Austrian and Belgian Pandur APCs.

Currently RUAG is offering a Leopard 2A4 upgrade - does it work for CR2 aswell?

In general it is unkown how the UK MoD wants the CR2 to be upgraded. It is understood that the scope of the upgrade is rather limited, as the budget is very tight. Replacing the gun is expensive, because the interior of the Challenger 2 MBT is not configured for storing long 120 mm unitary rounds. In case of the CR2 fitted with the German L/55 gun as prototype during the CLIP, there was only proper stowage space for a total of 6 rounds (!) of main gun ammunition.

This 6 round compartment stores all the ammunition of the CLIP prototype...

In theory only Rheinmetall and RUAG/CMI can offer a main gun replacement with their own technology. Rheinmetall has developed the Rh 120 L/44 and L/55 guns of the Leopard 2 MBT, aswell as a 105 mm smoothbore gun and the 120 mm L/47 LLR (lightweight, low-recoil) gun.
RUAG has developed the 120 mm CTG (compact tank gun), which was designed with reduced recoil as a low-cost/low-modifcation upgrade option for various existing tanks. Jordan has tested this gun on a Challenger 1 tank, the M60 Phoenix upgrade prototype and on the Falcon-2 turret system, BAE used this gun for the CV-90/120 light tank and the Swiss Army trialed it on their Panzer 68 upgrade.
Depending on required maximum recoil and muzzle break, the CTG has a length of 47 to 51 calibres.

Will CMI or RUAG offer the CTG to the UK?

However it is unclear wether RUAG or CMI could offer this gun to the British Army (even if they could afford major modifcations to the CR2 interior) - CMI has bought at least some rights of marketing the CTG to at least some markets. Maybe CMI bought the full rights, or RUAG and CMI agreed on both having full rights for this design. 

Another interesting concept, that however might as well be too expensive for the British Army, just as fitting a smoothbore, is the idea of mounting a new turret on a Challenger 2 hull. The turrets of the M1 Abrams and of the Leopard 2 can fit onto the turret ring of a Challemger 2 hull, but require some deeper modifications, which again could be too expensive for the British military. The M1 Abrams turret does not include most of the gun and turret drives, which are located in the tank's hull and are also hydraulic in the M1 Abrams. This is an important difference to the CR2 turret, which includes electric gun and turret drives. US trials have also revealed that upgunning the M1 Abrams with the longer L/55 gun of the Leopard 2A6 requires deeper modifications, which is why it was judged as being to expensive for the US Army. The big advantage of a M1 Abrams turret would be the rather large ammunition load of 34 or 36 rounds (depending on which racks are installed).
The Leopard 2 turret has electrical drives housed in the turret, so that it would be easier to integrate onto a CR2 hull - however the Leopard 2 stores only 15 round main gun ammunition in the turret buslte, so that the CR2 hull would require modifications for storing further ammo.
CMI is specialized on guns and turrets, so they could offer a version of their Cockerill XC-8 105-120HP turret fitted with a 120 mm smoothbore gun, if the turret rings are compatible. Problematic is in this case the different level of protection (CMI's turret is lacking thick composite armor) and the fact that the British Army might not like being forced to utilize an autoloader.

According to Jane's IHS only two contenders will be shortlisted. I'd bet that this will be BAE and either General Dynamics or Lockheed Martin - simply because they have the best position in British politics and they have manufacturing facilities in the UK. The UK government was willing to increase the price tag for their Scout-SV programme by several millions, just to move the manufacturing site from Spain to Wales.
In terms of technology, I'd choose Rheinmetall, General Dynamics or KMW however. Unlike BAE these companies have state-of-the-art products available and do not make most of their living from old 1980s designs such as the Warrior or Bradley. Compared to CMI and Lockheed Martin, all of these companies do have manufacturing capabilities for deeper modifications and upgrades. RUAG is probably comparable, but lacks a wider portfolio and as many successfull contracts as Rheinmetall/KMW/GD.

Probably the Challenger 2 LEP will end up being only a minor improvment due to budget cuts. Some new ammunition maybe, an improved fire control system, a new APU and maybe some other digital stuff.