Japan Picks Rheinmetall and Milrem UGVs for Autonomous Ground Trials

Japan’s Ministry of Defense has initiated a new phase in its exploration of unmanned ground vehicles (UGVs), selecting two leading European platforms—the Rheinmetall Mission Master SP and Milrem Robotics’ THeMIS—for upcoming autonomous mobility and mission trials. This move signals Tokyo’s growing interest in integrating robotic systems into the Japan Ground Self-Defense Force (JGSDF) to address manpower shortages and enhance operational flexibility.

Strategic Context: Japan’s Push Toward Robotic Ground Systems

Faced with demographic pressures and evolving regional threats, Japan has been steadily increasing its investment in defense automation. The selection of two mature European UGV platforms reflects a deliberate strategy to evaluate proven technologies before committing to indigenous development or broader acquisition programs.

The Japanese Ministry of Defense’s Acquisition, Technology & Logistics Agency (ATLA) is overseeing these trials as part of a broader effort to assess the viability of UGVs in logistics support, ISR (intelligence, surveillance, reconnaissance), casualty evacuation (CASEVAC), and potentially direct combat support roles. According to ATLA documents from 2023–2024 budget cycles, several R&D lines have been allocated for unmanned systems under the “Future Ground Combat System” initiative.

Rheinmetall Mission Master SP: Compact Versatility

The Mission Master SP (Silent Partner), developed by Rheinmetall Canada, is a compact 8×8 wheeled UGV designed primarily for dismounted infantry support. It features hybrid-electric propulsion for low acoustic signature operations and can be configured for multiple roles including cargo transport, armed escort missions with remote weapon stations (RWS), or ISR via mast-mounted sensors.

Dimensions: ~2.95 m long; 1.65 m wide
Payload capacity: up to 600 kg
Autonomy suite: GPS-denied navigation; leader-follower mode; obstacle avoidance
C2 integration: Compatible with NATO-standard BMS; supports manned-unmanned teaming (MUM-T)

The platform has already undergone extensive evaluation with NATO forces including Canada, the UK, Netherlands, and Germany. Notably, it was deployed during NATO’s Exercise Allied Spirit in 2020 where it demonstrated autonomous resupply under contested conditions.

THeMIS by Milrem Robotics: Modular Heavy-Lift Platform

The Estonian-developed THeMIS (Tracked Hybrid Modular Infantry System), now part of EDGE Group UAE since its acquisition in early 2023, is one of the most widely fielded modular tracked UGVs globally. Its open architecture allows rapid integration of third-party payloads such as EO/IR sensors, jammers, loitering munitions launchers or RWS like FN Herstal’s deFNder or Kongsberg Protector Lite.

Dimensions: ~2.4 m long; ~2 m wide
Payload capacity: up to 750 kg
Missions supported: CASEVAC; ISR; EW payload carriage; armed overwatch
Batteries + diesel genset hybrid drive: Quiet operation + extended range (~15+ hrs endurance)

THeMIS has been operationally deployed by Ukraine since mid-2022 in logistics and CASEVAC roles under NATO EDA-funded deliveries. It has also seen use by France’s SCORPION program and tested by the USMC under experimentation efforts like Project Convergence.

A Comparative Evaluation Approach by ATLA

The Japanese trials are structured as comparative evaluations rather than competitive downselects at this stage. According to sources familiar with ATLA’s procurement philosophy—including recent UAV evaluations involving AeroVironment Puma LE—Japan prefers side-by-side testing under domestic terrain conditions before defining requirements for future programs.

This approach allows Japanese engineers to study foreign system architectures while informing potential domestic development paths via Mitsubishi Heavy Industries or Komatsu Defense Systems—both of which have shown prototypes at DSEI Japan and other expos.

The trials will reportedly focus on:

Maneuverability across mixed terrain including urban rubble zones typical of disaster relief scenarios
Cognitive autonomy performance without GNSS reliance—key due to regional jamming threats from China/North Korea
C4ISR integration with existing JGSDF tactical networks (e.g., Fujitsu’s C4I backbone)
Sustainability metrics such as battery runtime vs payload weight vs terrain type

Implications for Future JGSDF Force Structure

If successful—and followed by a formal acquisition program—these trials could lead to doctrinal shifts within the JGSDF infantry battalions. Potential applications include pairing UGVs with dismounted squads during island defense operations or using them as forward sensors during amphibious landings led by Amphibious Rapid Deployment Brigades.

The emphasis on modularity also aligns with Japan’s need for dual-use capabilities that can serve both combat missions and humanitarian assistance/disaster relief (HA/DR). For instance, CASEVAC-capable THeMIS variants could be deployed post-earthquake alongside engineering units without violating Article 9 constraints on offensive military posture.

A Broader Trend Toward Robotic Integration Across Asia-Pacific Forces

This move places Japan alongside South Korea—which has fielded Hyundai Rotem HR-Sherpa variants—and Australia—which is experimenting with BAE Systems’ M113-based optionally crewed vehicles—as early adopters of tactical ground robotics in Asia-Pacific militaries.

The key differentiator remains doctrine: while others explore semi-autonomous fire support roles aggressively (e.g., South Korea’s armed HR-Sherpa), Japan appears focused on logistics autonomy first—a reflection both of policy constraints and demographic realities within its SDF recruitment base.

Conclusion: A Measured but Strategic Step Forward

The selection of Rheinmetall’s Mission Master SP and Milrem’s THeMIS represents more than just technical evaluation—it marks an inflection point in how Japan envisions future ground warfare amidst shrinking manpower pools and rising operational complexity. While no formal procurement decision is expected before FY2026–27 budgets are finalized, these trials will shape both capability planning and industrial policy around unmanned systems integration within one of Asia’s most technologically advanced militaries.