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Air Force maintainer using a VR headset with a digital model on screen, illustrating XR applications for training and digital twin integration. / Photo by Molly Rhine / U.S. Navy via DVIDS (Photo ID 5283818)

Digital Twins and Extended Reality

Additive manufacturing ensures parts are available anywhere, but digital twins ensure military decision-makers know precisely when and why those parts are needed. Indeed, additive manufacturing redefines the supply chain, and digital twins transform how assets are managed. A digital twin is a virtual replica of a physical asset, continuously updated with real-time data. By mirroring the state of an aircraft, ship, or vehicle, digital twins allow engineers to test “what-if” scenarios, optimize operations, and foresee problems before they occur.

A landmark example is the collaboration between Gecko Robotics and L3Harris, which delivered an extended reality (XR) system for the U.S. Air Force. The XR system combines high-resolution scans with digital twins, allowing maintainers to see structural issues through immersive headsets, reducing inspection times and enabling remote collaboration.
European defence industries are equally engaged. The Franco-German Future Combat Air System (FCAS) program integrates digital twin technology into both aircraft and ground support, enabling seamless lifecycle management.

There is a price to pay for the power of digital twins, however: massive data integration requirements. Inputs from sensors, historical records, and simulations must be harmonized to build a useful twin. The defence sector—traditionally siloed—must shift toward data sharing across services and nations.

Despite these hurdles, digital twins offer unmatched advantages: lower costs, higher readiness, and the ability to rehearse maintenance actions in a zero-risk virtual environment.

Autonomous Systems and Robotics in Maintenance Support

While digital twins provide a virtual reflection of assets, autonomous systems carry this intelligence into the physical world, acting as robotic partners in inspection and repair. Digital twins create a virtual mirror of assets, allowing autonomous systems and robotics to be extended into the physical world. The Advanced Reconnaissance Vehicle (ARV) developed for the U.S. Marine

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Unmanned ground vehicle with robotic arm operated alongside troops, showing robotic assistance for inspection and repair tasks./ Photo by Molly Rhine / U.S. Navy via DVIDS (Photo ID 5283818)

Corps integrates modular robotics and AI tools to self-diagnose and facilitate servicing.

In naval operations, underwater robots now inspect hulls for cracks or corrosion without the need for divers. Gecko Robotics deploys wall-climbing machines to scan massive structures such as fuel tanks and submarine exteriors.

These technologies do not replace humans—they amplify their effectiveness. A single technician supported by inspection robots can do the work of a team, covering hazardous or confined spaces quickly and safely.

Robotics adoption also addresses a demographic challenge: many armed forces face shortages of skilled maintainers. By reducing repetitive manual work, autonomous systems free personnel for higher-value tasks. The obstacle lies in integration—robot-generated data must flow seamlessly into digital twin and logistics platforms. Achieving this requires open standards and interoperability, still a work in progress across NATO.

Connected Logistics and Cyber-Resilient Maintenance

Connectivity is the invisible backbone of modern defence maintenance. Once described as the Internet of Military Things (IoMT), the concept has matured into connected logistics: secure, decentralized systems resilient to cyber threats.

Every vehicle, aircraft, and weapon system now generates telemetry. These data flow into logistics platforms that anticipate spare part demand, schedule maintenance proactively, and even simulate fleet-wide readiness scenarios.

The U.S. Army’s Global Combat Support System (GCSS-Army) is one example, providing commanders with real-time insight into the health of their units. Similar initiatives in NATO allow multinational data exchanges so coalition forces can coordinate maintenance across borders.

But with connectivity comes vulnerability. Adversaries could corrupt maintenance data, trigger false alarms, or conceal critical faults. The authenticity of additive manufacturing files is another concern: a hacked blueprint could produce a defective part.

These worries make cybersecurity a core element of maintenance strategy, no less vital than protecting fuel convoys or ammunition depots.

Virtual Training and Augmented Reality for Maintainers

Even the most advanced tools require skilled personnel. Training maintainers has always been challenging, especially when access to complex systems is limited. This is where virtual maintenance training (VMT) and augmented reality (AR) are proving transformative.

VMT systems provide immersive 3D environments where technicians can practice disassembly and repair without touching real equipment. This is invaluable for nuclear submarines or stealth aircraft, where live training is restricted.

AR overlays digital guidance directly on the maintainer’s field of view, offering “X-ray” insights into hidden components or step-by-step instructions. The U.S. Air Force has deployed AR headsets for F-35 maintenance, and the German Bundeswehr is testing similar systems for Eurofighter support.

These technologies accelerate learning, standardize procedures, and reduce error rates. In multinational exercises, AR even bridges language barriers, with overlays delivering instructions in multiple languages simultaneously.

Challenges include the cost of XR hardware, connectivity in remote bases, and the need for constant updates of digital content. But the return on investment is clear: faster training, safer operations, and more resilient maintenance teams.

Performance-Based Logistics and S4000P

Technology alone does not deliver readiness. Contracting models and standards provide the structure that makes it work.
Performance-Based Logistics (PBL) has become the gold standard in defence contracting. Instead of paying suppliers for tasks or parts, militaries now pay for outcomes: availability, reliability, and cost efficiency. The U.S. Department of Defense reports PBL contracts can deliver 10–20% cost savings while improving readiness.

The S4000P standard, developed by European and U.S. aerospace associations, is the reference for preventive maintenance across defence programs. It provides a systematic method for defining tasks that ensure safety and readiness at minimal lifecycle cost.

Together, PBL and S4000P ensure cutting-edge technologies are anchored in a sustainable framework of accountability and best practice.

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Service member preparing a multirotor UAV for field operations, representing the role of drones in autonomous inspection and logistics. / Photo by Molly Rhine / U.S. Navy via DVIDS (Photo ID 5283818)

Challenges and Barriers

Despite the promise of these innovations, several cross-cutting challenges remain:

• Cybersecurity risks: Maintenance data and digital twins are prime targets for adversaries. Manipulating them could disable fleets without firing a shot.

• Certification and trust: 3D-printed parts, AI predictions, and autonomous robots must meet strict safety standards before full acceptance. Certification is often slower than innovation.

• Workforce transformation: Maintainers must now master data analytics, robotics, and cybersecurity alongside mechanics. This requires a major investment in training.

• Budgetary pressures: Initial investments in these technologies are high. Decision-makers must balance them against competing procurement priorities.

• Interoperability: NATO and coalition operations depend on shared standards. Without harmonization of data, certification, and AI models, joint maintenance risks fragmentation.

Beyond the technical and contractual hurdles, one of the greatest obstacles lies in cultural and organizational inertia. Armed forces, by nature, are conservative and risk-averse, and this is likely to slow the adoption of disruptive maintenance practices. Even when pilot projects prove successful, scaling them across entire fleets can take years due to rigid hierarchies, fragmented responsibilities, and reluctance to move away from established routines. Added to this are geopolitical supply chain dependencies, where reliance on rare materials or foreign suppliers undermines the very autonomy the right-to-repair and additive manufacturing aim to deliver. These cultural and geopolitical dimensions remind us that innovation in maintenance is not purely a technological challenge—it is also an institutional one. How these challenges are addressed will determine whether current pilot projects remain isolated or scale into the backbone of global defence maintenance.

Regional Perspectives

Although the trends toward innovation are global, the adoption of technology varies significantly across regions, reflecting different strategic priorities, industrial bases, and defence cultures.

• United States: The U.S. continues to lead in AI-enabled predictive maintenance and additive manufacturing, driven by strong investment in programs like ERM for naval fleets and 3D-printed parts for aircraft. Its emphasis is on deploying disruptive technologies quickly, even if certification frameworks are still evolving. The right-to-repair initiative also marks a major cultural shift, designed to reduce dependency on OEMs and speed up frontline readiness.

• Europe: European defence forces focus on standards and frameworks, such as S4000P for preventive maintenance and digital twin initiatives in multinational programs like FCAS. The EU’s collaborative approach emphasizes interoperability, sustainability, and lifecycle cost control. Robotics and AR-based training systems are being rolled out progressively, but adoption is often slowed by fragmented procurement and regulatory processes across EU member states.

• Asia-Pacific: Nations like Japan, South Korea, and Australia are prioritizing autonomy and resilience in maintenance. Japan has integrated AI into naval fleet diagnostics, South Korea is piloting predictive analytics for armoured vehicles, and Australia is at the forefront of deploying additive manufacturing in forward bases and submarines. In this region, where logistics chains may be stretched over vast maritime distances, self-sufficiency through AM and robotics is a strategic necessity.

While the technologies are universal, their application is shaped by local conditions. The U.S. favours rapid innovation, Europe emphasizes harmonization, and Asia-Pacific prioritizes resilience and autonomy. Together, they underline that maintenance has become a pillar of defence strategies worldwide.

The Bigger Picture: From Maintenance to Mission Assurance

The common thread across all these innovations is a transformation in mindset. Maintenance is no longer viewed as a cost centre or a back-office function. It is a strategic enabler of operational superiority.

• AI and digital twins create foresight.

• Additive manufacturing and right-to-repair create autonomy.

• Autonomous robots and XR tools create safety and efficiency.

• Connected logistics and cybersecurity create resilience.

• Standards and contracting frameworks create sustainability.

In military operations, downtime is vulnerability. The new maintenance arsenal ensures armed forces can deploy, fight, and return home with maximum effectiveness and minimum disruption.

Looking Ahead

As the defence sector looks toward 2030 and beyond, several questions remain open:

• How will cyber threats challenge predictive maintenance platforms?

• To what extent can autonomous systems replace human inspection and repair?

• Will right-to-repair and additive manufacturing reshape the relationship between militaries and OEMs?

• How will NATO harmonize digital twin frameworks across borders?

• Can training systems scale fast enough to close the skills gap in technical roles?

One thing is certain: the race for maintenance superiority is no less important than the race for hypersonic missiles or AI-driven command systems. Armed forces mastering these trends will enjoy both lower costs and a decisive operational edge.

Final Word

Maintenance in defence has moved to the forefront of innovation, blending data science, robotics, new manufacturing methods, immersive training, and smart contracting. For industry professionals, policymakers, and operators alike, the message is clear: maintenance is mission assurance.

Future wars may be won not just by who fires first, but by who keeps their equipment running longest, safest, and smartest.

Text: Prof. Diego Galar