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Katana: Nexter moving towards precision fire


Eagerly awaited by the French artillerymen, the Katana shell designed by Nexter passed the first test firing milestone last month. This is a major step for this first « Made in France » precision ammunition, the initial increment of which could be marketed in 2023.

It took Nexter less than two years to transition from the concept model exhibited at the Eurosatory 2018 show in Paris to its first successful evaluation in an operational environment. The campaign, which was postponed due to the health crisis, took place at the Bofors Test Center (BTC) in southern Sweden.

« All the CAS (Canard Actuation Systems) were deployed in accordance with the simulations. Thus, the shell could be fired along a trajectory that increased the firing range compared to a purely ballistic trajectory, » Nexter said in an official release.

The final validation of the piloting algorithms, the aerobalistics and all the electronic and mechanical functions depended on the firing trials. In addition, the terminal phase of shell control allowed to set the system’s range at 40 km, right in line with the Nexter Munitions products’ range and the capabilities of the current 52-caliber/155 mm guns. The Katana shell will be compatible from the get go with the CAESAR, the PzH 2000 and the RCH 155. The data collected will be used to adjust the digital model and to complete the wind tunnel tests carried out in September 2020 at the ONERA facilities.

Two decades of maturation

This test campaign is also the culmination of twenty years of dialogue with The French Directorate General of Armaments (DGA) and the end-user. A number of key technologies were outlined during several upstream study plans carried out between 2000 and 2012.

Nexter then decided to fine tune its model using its own resources, while maintaining close and ongoing ties with the DGA and the army staffs. « This means that we were allowed to present the project to them, ask technical questions and benefit from very valuable expertise« . When it first appeared in public in June 2018, the Katana shell reached a TRL 5 level of maturity, i.e. validation of the system in a simulated environment. The project was then sufficiently advanced to move into the actual product development phase, with the blessing of KNDS.

A mock-up showcased during Eurosatory 2018 (Nexter image)

The development of this shell has from the outset been carried out according to a new iterative approach, which is considered to be faster than the old one. « In reality, Katana is much more than just a product. It is a project that is the vector for transforming the ammunition department because we are applying a development and qualification process that we call ‘agile’, » Nexter explains.

The program now has 30 employees in an integrated platform at Nexter Munitions’ Bourges site. Several successive levels of performance were built in this platform, reminiscent to « Skunk Works ». The specification of these performance levels is not fixed, but evolves with the product, with each iteration loop being accompanied by validation tests, like the one carried out in December.

Accuracy is the key issue

Land forces express a growing need for precision ammunition. On the French side, the military’s attraction for this solution has only increased feedback from campaigns in Afghanistan and the Levant. The French Ministry of the Armed Forces has been thinking about 155 mm ammunition for a long time, and Nexter can finally respond to this issue thanks to Katana.

« What we are being asked to do today is to finally complete the family of operational applications with a product that can deliver precision at the first shot« . Indeed, the Katana shell is synonymous with an upgrade for gunners, who will now have a wider choice of solutions to conduct their mission.

The Katana shell will be the first French artillery ammunition which accuracy is based on the coupling of a GNSS receiver and an inertial unit. Déjà vu, notably with the Excalibur ammunition produced for a decade by Raytheon? Not quite, because the French concept is based on a GNSS receiver, capable of coupling with the American GPS in particular, but also with the European satellite constellation Galileo, which offers worldwide coverage and is more accurate than the American GPS. This is a major seeling point for Nexter, which states that « Katana will immediately benefit from the higher degree of precision provided by Galileo« .

CAESAR SPHs from the French Army 3rd Marine Artillery Regiment (3e RAMa image)

However, these new guidance solutions must also be proof to jamming, a major concern and an operational need that is beginning to become clearer. The first increment of Katana will thus have a limited capacity to resist interference from the GNSS receiver. The next increments will add further hardening in the face of various countermeasures, including electromagnetic interference. They will also refine the degree of accuracy by adding a semi-active laser seeker, a technology developed with Thales over a long period of time. This laser module, which will be integrated in a future increment, should eventually provide metric accuracy.

While customer expectations are mainly focused on this feature, Nexter is working in parallel on the issues of range and payload. Set at about 40 km following the latest trials, the range may increase according to user requirements. Nexter is already anticipating this additional requirement. Most subsequent launches are currently carried out using a modular warhead. For « tomorrow », Nexter intends to offer a monolithic propellant charge that will make it possible to increase the quantity of powder, with a positive effect on range.

The Katana shell will also be fitted with a new type of warhead. « We are making it more effective and able to carry more explosive than the Excalibur, » Nexter promises. While the shots are fired from inert shells, the future explosive charge has also been put to the test in static tests in a detonation chamber. This charge will allow the artilleryman to deal with several types of targets, including hardened ones, again in response to a need expressed by the French armed forces.

A modular and sovereign solution

If the process undertaken in France is proving to be longer and more complex than that of the competition, it is also because Nexter is giving priority to overcoming any « ITAR » type obstacles. « Our mission for defense is not only to provide operational superiority, but also the keys to its freedom of employment, » Nexter emphasizes. For Nexter, sovereignty is based on two challenges: having the capacity to produce on demand and without restriction, which means being able to rely on a European DTIB and controlled components without a « black box », and guaranteeing freedom of use for the armed forces, free of any restrictions vis-à-vis a foreign supplier.

Most of Katana’s components come from French companies, the main difficulty being the need to create certain components from scratch and to make others mature. This is a daring but time-consuming process, which explains Nexter’s late arrival in this segment. The drag reducer, for example, will be designed by Eurenco, a long-standing partner that already supplies this technology for some 105 and 155 mm shells. The approach is not limited to the French sector and includes a handful of European partners. For example, the steering actuators come from Switzerland, the inertial power plant from the United Kingdom. 

Nexter would like to be able to extend this sovereignty argument to any prospective customer. Thanks to its native modularity, the Katana shell can be adapted to the needs of a customer country on the basis of national solutions. « We are open to industrial cooperation and ready to engage in future increments with manufacturers in France and elsewhere, » Nexter comments. The first expressions of interest are already multiplying, mainly from customers engaged in consultation phases for ammunition supply over the next few years.

Towards a mass production in 2023

The sooner Nexter is able to demonstrate the above-mentioned capabilities, the sooner the DGA will be able to evaluate it under its own conditions to possibly find its interest. The incremental configuration of the program allows it to progress rapidly, so for the Katana team, the objective now is to be able to propose a first increment suitable for mass production in 2023.

The level of evaluation will be raised this year, with test firings on shells which this time will not only be piloted but also guided on coordinates. Previously recorded in the ammunition. Further adjustment phases should then lead to the evaluation of a fully functional system. In parallel, the Katana team will continue the development of new components, such as the drag reducer and the warhead.

Once maturity has been reached and the definition of the shell has been decided, Nexter will enter an industrial qualification phase in 2022, including tests « of various kinds that will validate the fact that the ammunition is robust, reliable and safe to use« . The first demonstrations for the benefit of the various prospects could take place in 2023 at the latest, or even earlier. With, why not, the first commercial successes in sight for the discreet Katana team.


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